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Sample records for acid anhydride cured

  1. Method for production of dicarbonic acid anhydrides

    International Nuclear Information System (INIS)

    Mistr, A.; Necas, J.; Polak, V.

    1975-01-01

    A method is described of producing dicarboxylic acid anhydrides by the reaction of maleic acid anhydride with olefins. The synthesis is initiated by gamma radiation at a total dose of 10 4 to 10 6 rads in the presence of an organic solvent. The addition reactions of maleic acid anhydride to 1-hexadecene, 1-octene and cyclohexene with yields of 43%, 17% and 11%, respectively, are specified. (L.K.)

  2. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    International Nuclear Information System (INIS)

    Fan, Mengjin; Liu, Jialin; Li, Xiangyuan; Cheng, Jue; Zhang, Junying

    2013-01-01

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The T g and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar

  3. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Mengjin; Liu, Jialin; Li, Xiangyuan [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Cheng, Jue, E-mail: chengjue@mail.buct.edu.cn [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Junying, E-mail: zjybuct@gmail.com [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2013-02-20

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The T{sub g} and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar.

  4. Compatibility of anhydride cured epoxies with hexanitroazobenzene (HNAB) and hexanitrostilbene (HNS)

    International Nuclear Information System (INIS)

    Massis, T.M.; Wischmann, K.B.

    1985-01-01

    The explosives HNAB (hexanitroazobenzene) and HNS (hexanitrostilbene) have compatibility problems with amine-cured epoxy systems. A program was instituted to find compatible polymeric substitutes for use with these explosives. These polymeric materials must have rigid structures after curing for both adhesive and encapsulant applications. A promising class of epoxy materials using anhydride curing agents with various catalysts to trigger the cure reaction were developed. These polymeric systems have very good compatibility with HNS. Of those tested with HNAB, the anhydride epoxy system that used uranyl nitrate as the catalyst was found to be marginally compatible while the others were incompatible. These results indicated further studies are needed. The CRT (chemical reactivity test) was used to evaluate the compatibility of these materials. 6 references, 2 figures, 5 tables

  5. A self-crosslinking thermosetting monomer with both epoxy and anhydride groups derived from Tung oil fatty acids: Synthesis and properties

    Science.gov (United States)

    A self-crosslinking compound with epoxy groups and anhydride groups (GEMA) has been successfully synthesized from Tung oil fatty acid by reacting with maleic anhydride via the Diels-Alder reaction. GEMA has very good storage stability and can be cured with trace amounts of tertiary amine. This advan...

  6. Selective deoxygenation of stearic acid via an anhydride pathway

    NARCIS (Netherlands)

    Hollak, S.A.W.; Bitter, W.; Haveren, van J.; Es, van D.S.

    2012-01-01

    Stearic anhydride is proposed as reactive intermediate in the hydrogen free decarbonylation and ketonization of stearic acid over Pd/Al2O3 at 523 K. This information is crucial towards developing of a selective low temperature decarbonylation process of fatty acids towards olefins.

  7. Anhydrides-Cured Bimodal Rubber-Like Epoxy Asphalt Composites: From Thermosetting to Quasi-Thermosetting

    Directory of Open Access Journals (Sweden)

    Yang Kang

    2016-03-01

    Full Text Available The present engineering practices show the potential that epoxy asphalt composites (EACs would be a better choice to obtain long life for busy roads. To understand the service performance–related thermorheological properties of prepared bimodal anhydrides-cured rubber-like EACs (REACs, a direct tensile tester, dynamic shear rheometer and mathematical model were used. Tensile tests demonstrate that all the REACs reported here are more flexible than previously reported anhydrides-cured REACs at both 20 and 0 °C. The better flexibility is attributed to the change of bimodal networks, in which cross-linked short chains decreased and cross-linked long chains increased, relatively. Strain sweeps show that all the REACs have linear viscoelastic (LVE properties when their strains are smaller than 1.0% from −35 to 120 °C. Temperature sweeps illustrate that the thermorheological properties of REACs evolve from thermosetting to quasi-thermosetting with asphalt content, and all the REACs retain solid state and show elastic properties in the experimental temperature range. A Cole–Cole plot and Black diagram indicate that all the REACs are thermorheologically simple materials, and the master curves were constructed and well-fitted by the Generalized Logistic Sigmoidal models. This research provides a facile approach to tune the thermorheological properties of the REACs, and the cheaper quasi-thermosetting REAC facilitates their advanced applications.

  8. Indirect rapid prototyping of antibacterial acid anhydride copolymer microneedles

    International Nuclear Information System (INIS)

    Boehm, Ryan D; Miller, Philip R; Singh, Ritika; Narayan, Roger J; Shah, Akash; Stafslien, Shane; Daniels, Justin

    2012-01-01

    Microneedles are needle-like projections with microscale features that may be used for transdermal delivery of a variety of pharmacologic agents, including antibacterial agents. In the study described in this paper, an indirect rapid prototyping approach involving a combination of visible light dynamic mask micro-stereolithography and micromolding was used to prepare microneedle arrays out of a biodegradable acid anhydride copolymer, Gantrez® AN 169 BF. Fourier transform infrared spectroscopy, energy dispersive x-ray spectrometry and nanoindentation studies were performed to evaluate the chemical and mechanical properties of the Gantrez® AN 169 BF material. Agar plating studies were used to evaluate the in vitro antimicrobial performance of these arrays against Bacillus subtilis, Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Large zones of growth inhibition were noted for Escherichia coli, S. aureus, Enterococcus faecalis and B. subtilis. The performance of Gantrez® AN 169 BF against several bacteria suggests that biodegradable acid anhydride copolymer microneedle arrays prepared using visible light dynamic mask micro-stereolithography micromolding may be useful for treating a variety of skin infections. (communication)

  9. Modification of wheat starch with succinic acid/acetic anhydride and azelaic acid/acetic anhydride mixtures I. Thermophysical and pasting properties.

    Science.gov (United States)

    Subarić, Drago; Ačkar, Durđica; Babić, Jurislav; Sakač, Nikola; Jozinović, Antun

    2014-10-01

    The aim of this research was to investigate the influence of modification with succinic acid/acetic anhydride and azelaic acid/acetic anhydride mixtures on thermophysical and pasting properties of wheat starch. Starch was isolated from two wheat varieties and modified with mixtures of succinic acid and acetic anhydride, and azelaic acid and acetic anhydride in 4, 6 and 8 % (w/w). Thermophysical, pasting properties, swelling power, solubility and amylose content of modified starches were determined. The results showed that modifications with mixtures of afore mentioned dicarboxylic acids with acetic anhydride decreased gelatinisation and pasting temperatures. Gelatinisation enthalpy of Golubica starch increased, while of Srpanjka starch decreased by modifications. Retrogradation after 7 and 14 day-storage at 4 °C decreased after modifications of both starches. Maximum, hot and cold paste viscosity of both starches increased, while stability during shearing at high temperatures decreased. % setback of starches modified with azelaic acid/acetic anhydride mixture decreased. Swelling power and solubility of both starches increased by both modifications.

  10. Preparation of epoxy/zirconia hybrid materials via in situ polymerization using zirconium alkoxide coordinated with acid anhydride

    International Nuclear Information System (INIS)

    Ochi, Mitsukazu; Nii, Daisuke; Harada, Miyuki

    2011-01-01

    Highlights: → Novel epoxy/zirconia hybrid materials were synthesized via in situ polymerization using zirconium alkoxide coordinated with acid anhydride. → The half-ester compound of acid anhydride desorbed from zirconium played as curing agent of epoxy resin. → The zirconia was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale by synchronizing the epoxy curing and sol-gel reactions. → The refractive indices of the hybrid materials significantly improved with an increase in the zirconia content. - Abstract: Novel epoxy/zirconia hybrid materials were synthesized using a bisphenol A epoxy resin (diglycidyl ether of bisphenol A; DGEBA), zirconium(IV)-n-propoxide (ZTNP), and hexahydrophthalic anhydride (HHPA) via in situ polymerization. HHPA played two roles in this system: it acted as a modifier to control the hydrolysis and condensation reactions of zirconium alkoxide and also as a curing agent - the half-ester compound of HHPA desorbed from zirconium reacted with the epoxy resin to form the epoxy network. As a result, both the sol-gel reaction and epoxy curing occurred simultaneously in a homogeneous solution, and organic-inorganic hybrid materials were readily obtained. Further, the zirconia produced by the in situ polymerization was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale; thus, hybrid materials that exhibited excellent optical transparency were obtained. Furthermore, the heat resistance of the hybrid materials could be improved by hybridization with zirconia. And, the refractive indices of the hybrid materials significantly improved with an increase in the zirconia content.

  11. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana C.

    2010-01-01

    Full Text Available A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass. Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF and hexamethoxymethyl melamine resin (HMMMF. Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant

  12. The behaviour of tungsten electrodes in a mixture of acetic acid and acetic anhydride

    International Nuclear Information System (INIS)

    Pastor, T.J.; Vajgand, V.H.

    1976-01-01

    Tungsten electrodes have advantageously been used for potentiometric end-point detection in perchloric acid titration of bases in a mixture of acetic acid and acetic anhydride. They have also given good results in biamperometric detection of the equivalence point in continuous coulometric titration of small quantities of bases and acids in the same solvent. Tungsten electrodes in the presence of quinhydrone behave like platinum electrodes, but in biamperometric end-point determination in the absence of quinhydrone it is better to remove the oxide layer from their surface. Some other factors affecting their behaviour have also been studied. Errors in determination do not exceed +-2% even in titration of very small quantities of substances. (author)

  13. Partial oxidation of D-xylose to maleic anhydride and acrylic acid over vanadyl pyrophosphate

    International Nuclear Information System (INIS)

    Ghaznavi, Touraj; Neagoe, Cristian; Patience, Gregory S.

    2014-01-01

    Xylose is the second most abundant sugar after glucose. Despite its tremendous potential to serve as a renewable feedstock, few commercial processes exploit this resource. Here, we report a new technology in which a two-fluid nozzle atomizes a xylose-water solution into a capillary fluidized bed operating above 300 °C. Xylose-water droplets form at the tip of the injector, vaporize then react with a heterogeneous mixed oxide catalyst. A syringe pump metered the solution to the reactor charged with 1 g of catalyst. Product yield over vanadyl pyrophosphate was higher compared to molybdenum trioxide-cobalt oxide and iron molybdate; it reached 25% for maleic anhydride, 17% for acrylic acid and 11% for acrolein. Gas residence time was 0.2 s. The catalyst was free of coke even after operating for 4 h – based on a thermogravimetric analysis of catalyst withdrawn from the reactor. Below 300 °C, powder agglomerated at the tip of the injector at 300 °C; it also agglomerated with a xylose mass fraction of 7% in water. - Highlights: • D-xylose reacts to form maleic anhydride and acrylic acid above 250 °C. • Vanadyl pyrophosphate is both active and selective for maleic and acrylic acid. • Acid and acrolein yield approaches 50% for a xylose mass fraction of 3% in water. • Catalyst agglomerates at low temperatures and high xylose aqueous mass fraction. • Atomization quality is a determining factor to minimize agglomeration

  14. Anhydrous formic acid and acetic anhydride as solvent or additive in nonaqueous titrations.

    Science.gov (United States)

    Buvári-Barcza, A; Tóth, I; Barcza, L

    2005-09-01

    The use and importance of formic acid and acetic anhydride (Ac2O) is increasing in nonaqueous acid-base titrations, but their interaction with the solutes is poorly understood. This paper attempts to clarify the effect of the solvents; NMR and spectrophotometric investigations were done to reveal the interactions between some bases and the mentioned solvents. Anhydrous formic acid is a typical protogenic solvent but both the relative permittivity and acidity are higher than those of acetic acid (mostly used in assays of bases). These differences originate from the different chemical structures: liquid acetic acid contains basically cyclic dimers while formic acid forms linear associates. Ac2O is obviously not an acidic but an aprotic (very slightly protophilic) solvent, which supposedly dissociates slightly into acetyl (CH3CO+) and acetate (AcO-) ions. In fact, some bases react with Ac2O forming an associate: the Ac+ group is bound to the delta- charged atom of the reactant while AcO- is associated with the delta+ group at appropriate distance.

  15. Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

    International Nuclear Information System (INIS)

    Klinpituksa, P; Kongkalai, P; Kaesaman, A

    2014-01-01

    The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin

  16. EFFECT OF SUBSTITUTION POSITION OF HYDROXY GROUP AT BENZOIC ACID ON THE LUMINESCENT AND DEGRADATION PROPERTIES OF POLY[DI(CARBOXYPHENYL) SUCCINATE-co-SEBACIC ANHYDRIDE]S

    Institute of Scientific and Technical Information of China (English)

    Jun Fan; Hong-liang Jiang; Kang-jie Zhu

    2007-01-01

    In this work, two new diacids, di(m-carboxyphenyl) succinate (m-dCPS) and di(o-carboxyphenyl) succinate (o-dCPS), were synthesized by reaction of m-, o-hydroxy benzoic acid with succinic chloride, respectively. Their corresponding copolymers with sebacic acid (SA), P(m-dCPS:SA) and P(o-dCPS:SA), were prepared by melt copolycondensation and characterized by NMR, UV and DSC methods. Compared with inherently fluorescent poly[di(p-carboxyphenyl) succinateco-sebacic anhydride] (P(p-dCPS:SA)), P(m-dCPS:SA) and P(o-dCPS:SA) displayed different luminescent properties. P(m-dCPS:SA) could emit fluorescence under the excitation of both visible and UV light, while P(o-dCPS:SA) could only emit fluorescence when excited with UV light. Degradation rate of the two new copolyanhydrides increased with the increase of SA fraction in the copolymers. In addition, P(o-dCPS:SA) degraded more rapidly than P(m-dCPS:SA) with the same composition. Typical surface-degradation characteristics of these copolyanhydrides were observed.

  17. Tensile and morphology properties of PLA/LNR blends modified with maleic anhydride grafted-polylactic acid and -natural rubber

    Science.gov (United States)

    Ruf, Mohd Farid Hakim Mohd; Ahmad, Sahrim; Chen, Ruey Shan; Shahdan, Dalila; Zailan, Farrah Diyana

    2018-04-01

    This research was carried out to investigate the addition of grafted copolymers of maleic anhydride grafted-polylactic acid(PLA-g-MA) and maleic anhydride grafted-natural rubber (NR-g-MA) on the tensile and morphology properties of polylactic acid/ liquid natural rubber (PLA/LNR) blends. Prior to blend preparation, the PLA-g-MA and NR-g-MA was first self-synthesized using maleic anhydride (MA) and dicumyl peroxide (DCP) as initiator together with the PLA and NR respectively. The PLA/LNR, PLA/LNR/PLA-g-MA and PLA/LNR/NR-g-MA blends were prepared via melt-blending method. The loading of PLA-g-MA and NR-g-MA was varied by 5, 10 and 15 wt% respectively. The addition of PLA-g-MA led to increment in tensile strength with 5 and 10 wt% while NR-g-MA gives lower than controlled sample (PLA/LNR blend). Scanning electron microscope (SEM) showed the interaction of the components in the blends. The PLA/LNR compatibilized with PLA-g-MA and NR-g-MA shows greater dispersion and adhesion.

  18. Diastereoselective and one-pot synthesis of trans-isoquinolonic acids via three-component condensation of homophthalic anhydride, aldehydes, and ammonium acetate catalyzed by aspartic acid

    Czech Academy of Sciences Publication Activity Database

    Ghorbani-Choghamarani, A.; Hajjami, M.; Norouzi, M.; Abbasityula, Y.; Eigner, Václav; Dušek, Michal

    2013-01-01

    Roč. 69, č. 32 (2013), s. 6541-6544 ISSN 0040-4020 Grant - others:AVČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : isoquinolonic acid * diastereoselective * aldehyde * homophthalic anhydride * ammonium acetate Subject RIV: CC - Organic Chemistry Impact factor: 2.817, year: 2013

  19. The effects of reactive diluents on the mechanical behaviour of an anhydride-cured epoxy resin system

    International Nuclear Information System (INIS)

    Stevens, G.T.; Lupton, A.W.

    1976-10-01

    A study was made of the tensile behaviour at room temperature, 75 0 C and 100 0 C, of diglycidyl ether of bisphenol A resin systems modified by the introduction of (i) a linear mono-epoxide aliphatic glycidyl ether, (ii) a highly branched mono-epoxide glycidyl ester of a saturated tertiary mono-carboxylic acid, (iii) a mixture of the linear mono-glycidyl and diglycidyl ethers of butanediol and (iv) a low viscosity diepoxide and also an elastomer (Hycar CTBN). Resin systems showing relatively high elongation to failure without severe degradation of strength or stiffness at elevated temperatures were obtained. (author)

  20. Monosaccharide anhydrides, monocarboxylic acids and OC/EC in PM1 aerosols in urban areas in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Křůmal, Kamil; Mikuška, Pavel; Večeřa, Zbyněk

    2015-01-01

    Roč. 6, č. 6 (2015), s. 917-927 ISSN 1309-1042 R&D Projects: GA MŽP SP/1A3/148/08; GA ČR(CZ) GBP503/12/G147; GA ČR GA13-01438S; GA ČR(CZ) GA14-25558S Institutional support: RVO:68081715 Keywords : Monosaccharide anhydrides * carboxylic acids * fatty acids * organic carbon * biomass burning Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.401, year: 2015

  1. Preparations and applications in UV curing coatings of epoxy acrylates containing carboxyl

    International Nuclear Information System (INIS)

    Wu Yu Min

    1999-01-01

    This paper introduces preparations of epoxy acrylates containing carboxyl through the reactions of epoxy acrylates with butanedioic anhydride, pentanedioic anhydride, cis-butenedioic anhydride, phthalic anhydride, tetrabromophthalic anhydride and -tetrahydrophthalic anhydride. These epoxy acrylates containing carboxyl have been applied to UV-curing coatings and their effects on properties of UV-curing coatings have been studied

  2. Cellulose-polyhydroxylated fatty acid ester-based bioplastics with tuning properties: Acylation via a mixed anhydride system.

    Science.gov (United States)

    Heredia-Guerrero, José A; Goldoni, Luca; Benítez, José J; Davis, Alexander; Ceseracciu, Luca; Cingolani, Roberto; Bayer, Ilker S; Heinze, Thomas; Koschella, Andreas; Heredia, Antonio; Athanassiou, Athanassia

    2017-10-01

    The synthesis of microcrystalline cellulose (MCC) and 9,10,16-hydroxyhexadecanoic (aleuritic) acid ester-based bioplastics was investigated through acylation in a mixed anhydride (trifluoroacetic acid (TFA)/trifluoroacetic acid anhydride (TFAA)), chloroform co-solvent system. The effects of chemical interactions and the molar ratio of aleuritic acid to the anhydroglucose unit (AGU) of cellulose were investigated. The degree of substitution (DS) of new polymers were characterized by two-dimensional solution-state NMR and ranged from 0.51 to 2.60. The chemical analysis by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) confirmed the presence of aleuritate groups in the structure induces the formation of new H-bond networks. The tensile analysis and the contact angle measurement confirmed the ductile behavior and the hydrophobicity of the prepared bioplastics. By increasing the aleuritate amounts, the glass transition temperature decreased and the solubility of bioplastic films in most common solvents was improved. Furthermore, this new polymer exhibits similar properties compared to commercial cellulose derivatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. α-Costic anhydride

    Directory of Open Access Journals (Sweden)

    Moha Berraho

    2010-03-01

    Full Text Available The title compound [systematic name: 2-(4a,8-dimethyl-1,2,3,4,4a,5,6,8a-octahydronaphthalen-2-ylacrylic acid anhydride], C30H42O3, is a new isocostic anhydride which was synthesized from the aerial part of Inula Viscosa (L Aiton [or Dittrichia Viscosa (L Greuter]. The molecule adopts an essentially linear shape with two terminal fused-rings bridged by the anhydride group. The external rings have the same conformation (half-chair while each of the two inner rings has an almost ideal chair conformation. In the crystal, intermolecular C—H...O interactions link the molecules into a two-dimensional array in the bc plane.

  4. Preparation and structural characterisation of novel and versatile amphiphilic octenyl succinic anhydride-modified hyaluronic acid derivatives

    DEFF Research Database (Denmark)

    Eenschooten, Corinne Diane; Guillaumie, Fanny; Kontogeorgis, Georgios

    2010-01-01

    and structurally characterised by Fourier transform-infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (1H NMR). The influence of four reaction parameters on the DS of the derivatives was studied by means of an experimental design. The results showed that the OSA/HA molar ratio, the buffer......The purpose of the present study was to prepare amphiphilic hyaluronic acid (HA) derivatives and to study the influence of a selection of reaction parameters on the degree of substitution (DS) of the derivatives. Octenyl succinic anhydride (OSA)–modified HA (OSA–HA) derivatives were prepared...... (NaHCO3) concentration and their interaction had the largest influence while the HA concentration and the reaction time only had a negligible effect. According to 1H NMR the maximum DS achieved within the experimental conditions tested was 43% per disaccharide unit. Moreover optimal reaction...

  5. Two-step modification of poly(D, L-lactic acid) by ethylenediamine-maleic anhydride

    International Nuclear Information System (INIS)

    Cao Chengbo; Zhu Fanglian; Yu Xueli; Wang Qin; Wang Chuandong; Li Baolu; Lv Ronghui; Li Musen

    2008-01-01

    Poly(lactic acid) (PLA) was modified by maleic anhydride (MAH), then the resultant MAH modified PLA (MPLA) was acylated with ethylenediamine (EDA), so EDA-MAH modified PLA (EMPLA) was prepared. The results of DSC, FT-IR and NMR testified that MAH and EAD were successfully introduced into the original polymer. The hydrophilicity of EMPLA was considerably increased compared with that of PLA. The degradation experiment showed that the introduction of EDA into the original polymer could neutralize the carboxyl end groups of the degradation products. The results of SEM and MTT of rat osteoblasts cultured in vitro showed that the cytocompatibility and cell adhesion of the modified materials were significantly increased compared with the original polymer, especially EMPLA; the number of cells were obviously increased and cells attached firmly to the material; these were ascribed to the EDA neutralizing the carboxyl end groups of the degradation products

  6. Reaction of N-acetylneuraminic acid derivatives with perfluorinated anhydrides: a short access to N-perfluoracylated glycals with antiviral properties.

    Science.gov (United States)

    Rota, Paola; Allevi, Pietro; Mattina, Roberto; Anastasia, Mario

    2010-08-21

    An efficient short protocol for the preparation of N-perfluoroacylated glycals of neuraminic acid, by simple short treatment of differently protected N-acetylneuraminic acid with perfluorinated anhydrides in acetonitrile at 135 degrees C, is reported, together with a rationalitazion of the reaction that allows the alternative formation of N-perfluoroacylated 1,7-lactones to be previewed under the same reaction conditions.

  7. SureCure{sup (R)}-A new material to reduces curing time and improve curing reproducibility of lead-acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Boden, David P.; Loosemore, Daniel V.; Botts, G. Dean [Hammond Lead Products Division, Hammond Group Inc., 2323 165th Street, Hammond, IN 46320 (United States)

    2006-08-25

    This paper introduces a technology that considerably reduces the time to cure the positive plates of lead-acid batteries. In each of several full-scale trials at automotive and industrial battery manufacturers, the simple replacement of 1wt.% of leady oxide with finely-divided tetrabasic lead sulfate (SureCure(TM) by Hammond Group Inc.) is shown to accelerate significantly the conversion of tribasic lead sulfate (3BS) to tetrabasic lead sulfate (4BS) in the curing process while improving crystal structure and reproducibility. Shorter curing times result in reduced labour and energy costs, as well as reduced fixed (curing chambers and plant footprint) and working (plate inventory) capital investment. (author)

  8. Investigation of the ageing effects on phenol-urea-formaldehyde binder and alkanol amine-acid anhydride binder coated mineral fibres

    DEFF Research Database (Denmark)

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.

    2013-01-01

    -ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to identify the chemical changes occurring in the PUF binder coated mineral fibres and alkanol amine-acid anhydride binder coated mineral fibres during that ageing. The samples were aged in a climate......Phenol-Urea-Formaldehyde (PUF) binder coated mineral fibres' mechanical properties have been observed to degrade during ageing at elevated temperatures and humidity, while alkanol amine-acid anhydride binder based mineral fibres exhibited better ageing properties for same duration of ageing. X...... chamber for 7 days at 70 °C and 95% relative humidity. In the case of the PUF binder coated fibres, quantitative XPS measurements showed some significant changes in the atomic composition of the PUF binder coated mineral fibres after ageing, including decreased urea and carbonyl groups concentrations...

  9. Influence of Maleic Anhydride/Glycidyl Methacrylate Cografted Polylactic Acid on Properties of Wood Flour/PLA Composites

    Directory of Open Access Journals (Sweden)

    DU Jun

    2017-12-01

    Full Text Available Graft copolymers of PLA-g-MAH, PLA-g-GMA and PLA-co-MAH/GMA were prepared by means of melt grafting. The structure of the graft copolymers were characterized by FTIR.Wood flour/PLA composites were prepared by injection molding with three kinds of graft copolymers as compatibilizers, and the fractured morphology of composites was investigated by scanning electron microscope (SEM. Results show that there is no obvious phase interface between wood flour and PLA,which indicating the interfacial compatibility of wood flour/PLA composites is improved after adding different graft copolymers. The determination results of mechanical properties, processing flowability and dynamic rheological property of composites prepared with different graft copolymers reveal that, compared to the composite without compatibilizer, the tensile strength and impact strength of wood flour/PLA composites are increased by 9.54% and 7.23% respectively, and the equilibrium torque, shear heat, storage modulus and complex viscosity are all increased after adding maleic anhydride/glycidyl methacrylate cografted polylactic acid.

  10. Membrane polypeptide in rabbit erythrocytes associated with the inhibition of L-lactate transport by a synthetic anhydride of lactic acid

    International Nuclear Information System (INIS)

    Donovan, J.A.; Jennings, M.L.

    1985-01-01

    The synthetic lactyl anhydride isobutylcarbonyl lactyl anhydride (iBCLA), a selective and potent inhibitor of L-(+)-lactate transport in rabbit erythrocytes, reduces the chemical labeling of a 40-50-kdalton polypeptide by tritiated 4,4'-diisothiocyanato-2,2'-dihydrostilbenedisulfonate ([ 3 H]H 2 DIDS). iBCLA does so in a dose-dependent manner at concentrations that strongly inhibit lactate-lactate exchange but not chloride-phosphate exchange. These labeling experiments and inhibition reversal studies using iBCLA, p-(chloro-mercuri)benzenesulfonic acid (pCMBS), and dithiothreitol (DDT) suggest that iBCLA does not act at sulfhydryl groups but at or near an amino group that is near a disulfide linkage in the polypeptide which catalyzes lactate transport. These experiments support the association between specific monocarboxylate transport and a 40-50-kdalton membrane-bound polypeptide of the rabbit erythrocyte

  11. Acid curing and baking of bastnasite ore and concentrate

    International Nuclear Information System (INIS)

    Topkaya, Y.; Akkurt, S.

    1998-01-01

    Full text: In this study, the hydrometallurgical evaluation of a rare earth ore as well as a concentrate obtained from this was done at laboratory. For the mentioned study, a bastnasite type rare earth ore located in Beylikahir in Turkey was used. The total rare earth oxide (REO) content of the deposit was estimated to be 1 million tons with an average concentration of 3.42%REO. The rare earths were contained in bastnasite mineral. The other constituents of the ore were calcium fluoride (52.5%), barite (25.4%), calcite (2.8%) and minor amounts of thorium, iron, manganese, etc. The bastnasite mineral occurred either as cement material between fluoride and barite particles or as intimately associated with these minerals. The rare earth elements were enriched considerably in sub-sieve sizes. After extensive research about the physical concentration of this ore, two different metallurgical routes were followed for the extraction of REE from the ore itself or the preconcentrate obtained by attrition scrubbing and desliming by cyclones. In order to increase the grade of the concentrate, upgrading of the preconcentrate by multigravity was also tried. The two metallurgical routes tested were: Sulphuric acid curing and water leaching; Sulphuric acid baking and subsequent water leaching. The results of the leaching experiments were found to be quite promising. Leach recoveries up to 90% were easily obtainable. In the case of acid baking, hydrofluoric acid recover as a by-product was also possible

  12. Development and engineering application of rotating drum acid-curing equipment in uranium mills

    International Nuclear Information System (INIS)

    Liu Wenhua

    2006-01-01

    The development and engineering application of rotating drum acid-curing equipment for 'strong acid-curing and ferri-trickle leaching' process are introduced, including the design of main structure, problems appeared in the development and engineering application, and methods solved. (authors)

  13. Electron beam curing of dimer acid-based urethane acrylates for pressure sensitive adhesives

    International Nuclear Information System (INIS)

    Sasaki, Takashi; Takeda, Satoe; Shiraishi, Katsutoshi.

    1995-01-01

    Polyester urethane diacrylate prepolymers prepared from dimer acids (DUA) were cured with low energy electron beams to investigate adhesive properties of cured films. Among various type monomers added, monofunctional methacrylates such as isobornyl methacrylate (IBXMA) were effective for higher peel strength cured films although the dose-to-cure for the mixtures increased to 100 kGy or more. The increase in the molecular weight of prepolymers resulted in lower curing rates but higher peel strength. Aging tests up to 80degC for four weeks proved good stability in peel strength of the stored products. (author)

  14. Styrene-Assisted Maleic Anhydride Grafted Poly(lactic acid as an Effective Compatibilizer for Wood Flour/Poly(lactic acid Bio-Composites

    Directory of Open Access Journals (Sweden)

    Jun Du

    2017-11-01

    Full Text Available This study aimed to evaluate the effect of styrene-assisted maleic anhydride-grafted poly(lactic acid (PLA-g-St/MAH on the interfacial properties of wood flour/poly(lactic acid (PLA bio-composites. PLA-g-St/MAH was synthesized by free-radical melt grafting using styrene as a comonomer and dicumyl peroxide as an initiator. The structure of PLA-g-St/MAH was characterized by Fourier transform infrared spectroscopy. Wood flour/PLA composites were prepared by compression molding using PLA-g-St/MAH as a compatibilizer. The effects of PLA-g-St/MAH on the rheological and mechanical properties, as well as on the fractured surface morphology of the composites were investigated. Results indicated that storage modulus, complex viscosity, equilibrium torque, and shear heat were significantly increased. The mechanical properties of the wood flour/PLA composites were also significantly increased after the addition of PLA-g-St/MAH. The maximum values were achieved at the loading rate of 3 wt % because of the improved interfacial adhesion between the wood flour and the PLA matrix.

  15. The properties of poly(lactic acid)/starch blends with a functionalized plant oil: tung oil anhydride.

    Science.gov (United States)

    Xiong, Zhu; Li, Chao; Ma, Songqi; Feng, Jianxian; Yang, Yong; Zhang, Ruoyu; Zhu, Jin

    2013-06-05

    Bio-sourced polymers, polylactide (PLA) and starch, have been melt-blended by lab-scale co-extruder with tung oil anhydride (TOA) as the plasticizer. The ready reaction between the maleic anhydride on TOA and the hydroxyl on starch led TOA molecules to accumulate on starch and increased the compatibility of PLA/starch blends, which was confirmed by FT-IR analyses and SEM. The TOA could change the mechanical properties and physical behaviors of PLA/starch blends. DSC and DMA analysis show that the TOA layer on starch has an effect on the thermal behavior of PLA in the ternary blend. The enrichment of TOA on starch improves the toughness and impact strength of the PLA/starch blends. The adding amount of TOA in PLA/starch blends primarily determined the compatibility and mechanical properties of the resulted ternary blends. The tensile and impact fracture modes of the PLA/starch blend with or without TOA has also been investigated by SEM analysis. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  16. Preparation, characterization and thermal properties of styrene maleic anhydride copolymer (SMA)/fatty acid composites as form stable phase change materials

    International Nuclear Information System (INIS)

    Sari, Ahmet; Alkan, Cemil; Karaipekli, Ali; Onal, Adem

    2008-01-01

    Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the major drawback of them, limiting their utility area in thermal energy storage. The use of fatty acids as form stable PCMs will increase their feasibilities in practical applications due to the reduced cost of the LHTES system. In this regard, a series of styrene maleic anhydride copolymer (SMA)/fatty acid composites, SMA/SA, SMA/PA, SMA/MA, and SMA/LA, were prepared as form stable PCMs by encapsulation of fatty acids into the SMA, which acts as a supporting material. The encapsulation ratio of fatty acids was as much as 85 wt.% and no leakage of fatty acid was observed even when the temperature of the form stable PCM was over the melting point of the fatty acid in the composite. The prepared form stable composite PCMs were characterized using optic microscopy (OM), viscosimetry and Fourier transform infrared (FT-IR) spectroscopy methods, and the results showed that the SMA was physically and chemically compatible with the fatty acids. In addition, the thermal characteristics such as melting and freezing temperatures and latent heats of the form stable composite PCMs were measured by using the differential scanning calorimetry (DSC) technique, which indicated they had good thermal properties. On the basis of all the results, it was concluded that form stable SMA/fatty acid composite PCMs had important potential for practical LHTES applications such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard or floors impregnated with a form stable PCM due to their satisfying thermal properties, easy preparation in desired dimensions, direct usability without needing additional encapsulation thereby eliminating the thermal resistance caused by the shell and, thus, reducing the cost of

  17. Effect of curing modes of dual-curing core systems on microtensile bond strength to dentin and formation of an acid-base resistant zone.

    Science.gov (United States)

    Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Waidyasekera, Kanchana; Ikeda, Masaomi; Chen, Jihua; Nikaido, Toru; Tagami, Junji

    2011-12-01

    To evaluate the microtensile bond strength (μTBS) and acid-base resistant zone (ABRZ) of two dualcuring core systems to dentin using four curing modes. Sixty-four caries-free human molars were randomly divided into two groups according to two dual-curing resin core systems: (1) Clearfil DC Core Automix; (2) Estelite Core Quick. For each core system, four different curing modes were applied to the adhesive and core resin: (1) dual-cured and dual-cured (DD); (2) chemically cured and dual-cured (CD); (3) dual-cured and chemically cured (DC); (4) chemically cured and chemically cured (CC). The specimens were sectioned into sticks (n = 20 for each group) for the microtensile bond test. μTBS data were analyzed using two-way ANOVA and the Dunnett T3 test. Failure patterns were examined with scanning electron microscopy (SEM) to determine the proportion of each mode. Dentin sandwiches were produced and subjected to an acid-base challenge. After argon-ion etching, the ultrastructure of ABRZ was observed using SEM. For Clearfil DC Core Automix, the μTBS values in MPa were as follows: DD: 29.1 ± 5.4, CD: 21.6 ± 5.6, DC: 17.9 ± 2.8, CC: 11.5 ± 3.2. For Estelite Core Quick, they were: DD: 48.9 ±5.7, CD: 20.5 ± 4.7, DC: 41.4 ± 8.3, CC: 19.1 ± 6.0. The bond strength was affected by both material and curing mode, and the interaction of the two factors was significant (p < 0.001). Within both systems, there were significant differences among groups, and the DD group showed the highest μTBS (p < 0.05). ABRZ morphology was not affected by curing mode, but it was highly adhesive-material dependent. The curing mode of dual-curing core systems affects bond strength to dentin, but has no significant effect on the formation of ABRZ.

  18. Simultaneous efficient adsorption of Pb2+ and MnO4− ions by MCM-41 functionalized with amine and nitrilotriacetic acid anhydride

    International Nuclear Information System (INIS)

    Chen, Feiyun; Hong, Mingzhu; You, Weijie; Li, Chong; Yu, Yan

    2015-01-01

    Highlights: • MCM-41 was successfully modified with amine and nitrilotriacetic acid anhydride. • The adsorbent can simultaneously remove Pb 2+ and MnO 4 − by adjusting pH of the system. • The maximum adsorption capacities of Pb 2+ and MnO 4 − are 147 mg/g and 156 mg/g. • The absorbent exhibits good regeneration and reusability for 5 cycles use. - Abstract: A novel adsorbent NH 2 /MCM-41/NTAA, capable of simultaneous adsorption of cations and anions from aqueous solution, was prepared by immobilization of amine and nitrilotriacetic acid anhydride (NTAA) onto MCM-41. The structures and properties before and after surface modification were systematically investigated through X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM), nitrogen adsorption–desorption, and infrared spectroscopy (FTIR), thermogravimetry (TGA) and X-ray photoelectron spectroscopy (XPS). They together confirm that the amine and NTAA group were chemically bonded to the internal surface of the mesoporous. The NH 2 /MCM-41/NTAA were used to adsorb Pb 2+ and MnO 4 − in an aqueous solution in a batch system, and the maximum adsorption efficiency was found to occur at pH 5.0 and 3.0, respectively. NH 2 /MCM-41/NTAA exhibit preferable removal of Pb 2+ through electrostatic interactions and chelation, whereas it captures MnO 4 − by means of electrostatic interactions. The experimental data are fitted the Langmuir isotherm model reasonably well, with the maximum adsorption capacity of 147 mg/g for Pb 2+ and of 156 mg/g for MnO 4 − . The adsorption rates of both Pb 2+ and MnO 4 − are found to follow the pseudo-second order kinetics. Furthermore, the NH 2 /MCM-41/NTAA adsorbent performs good recyclability and reusability for 5 cycles use. This study indicates a potential applicability of NH 2 /MCM-41/NTAA as new absorbents for effective simultaneous adsorption of hazardous metal ions and anions from wastewater.

  19. Effects of electric fields in polymerization on enthalpy of PMAA anhydridization

    Energy Technology Data Exchange (ETDEWEB)

    Chang Zhenqi; Liu Gang; Zhang Zhicheng

    2004-02-19

    PMAA (polymethacrylic acid) polymerized by {gamma}-irradiation in electric field forms six-membered cyclic anhydride during heating process and the enthalpy of PMAA anhydridization was determined by DSC. Why the endothermic peak of PMAA anhydridization in DSC curve between 200 and 300 deg. C appears is particularly explained by calculation. The relations between applied electric field and the enthalpy of PMAA anhydridization are studied. The results show that, with the increases of the intensity of electric field in polymerization, the enthalpy of PMAA forming anhydrides nonlinearly increase, which might be related to orientation of carboxylic acid groups of the PMAA in an electric field.

  20. Blending of Low-Density Polyethylene and Poly-Lactic Acid with Maleic Anhydride as A Compatibilizer for Better Environmentally Food-Packaging Material

    Science.gov (United States)

    Setiawan, A. H.; Aulia, F.

    2017-05-01

    The common conventional food packaging materialsare using a thin layer plastic or film, which is made of a synthetic polymer, such as Low-Density Poly Ethylene (LDPE). However, the use of these polymers hasan adverse impact on the environment, because the synthetic polymersare difficult to degrade naturally. Poly-Lactic Acid (PLA) is a biodegradable polymer that can be substituted to synthetic polymers. Since LDPE and PLA have a difference in polarity, therefore the first step of research is to graft them with maleic anhydride (MAH) for increasing the properties of its miscibility. The interaction between them is confirmed by FTIR; whereas the environment issueis characterized by the water adsorption and biodegradability. The FTIR spectra indicated that there had been an interaction between LDPE and MAH and LDPE/LDPE-g-MAH/PLA blend. Increasing PLA content in the blend affected to the increasing in their water absorption and biodegradable. Poly-blend with 20% PLA content was the optimum composition for environmentally food packaging.

  1. EFFECTS.OF BORIC ACID ON THE CURE OF BORON-FILLED Y-3602 SILICONE GUM

    Energy Technology Data Exchange (ETDEWEB)

    Leichliter, G E

    1974-10-01

    The first two phases of a program designed to determine the effects of boric acid on the cure of Y-3602 silicone gum were conducted to evaluate extraction solvents and extraction time. The standard production formulation of B10-filled Y-3602 silicone gum was used in these evaluations. Results showed that the best solvent for reproducibility and high amine content was chloroform. The second phase indicated that extraction was essentially complete at the end of 4 hours.

  2. Dimethylthioarsinic anhydride: A standard for arsenic speciation

    International Nuclear Information System (INIS)

    Fricke, Michael; Zeller, Matthias; Cullen, William; Witkowski, Mark; Creed, John

    2007-01-01

    Dimethylthioarsinic acid (DMTA V ) has recently been identified in biological, dietary and environmental matrices. The relevance of this compound to the toxicity of arsenic in humans is unknown and further exposure assessment and metabolic studies are difficult to conduct because of the unavailability of a well characterized standard. The synthesis of DMTA V was accomplished by the reaction of dimethylarsinic acid (DMA V ) with hydrogen sulfide. The initial reaction product produced is DMTA V but multiple products over the course of the reaction are also observed. Therefore, a chromatographic separation was developed to monitor the reaction progress via LC-ICP-MS. In this synthesis, conversion of DMA V to DMTA V was not taken to completion to avoid the production of side products. The product was isolated from the starting material by standard organic techniques. Single crystal diffraction demonstrated that solid DMTA V is present in the form of the oxygen-bridged dimethylthioarsinic anhydride. Dissolution of the anhydride in water produces the acid form of DMTA V and the aqueous phase DMTA V provided a characteristic molecular ion of m/z 155 by LC-ESI-MS. The synthesis and isolation of dimethylthioarsinic anhydride provides a stable crystalline standard suitable for identification, toxicological study and exposure assessment of dimethylthioarsinic acid

  3. Dimethylthioarsinic anhydride: A standard for arsenic speciation

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Michael [United States Environmental Protection Agency, National Exposure Research Laboratory, Microbiological and Chemical Exposure Assessment Research Division, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Zeller, Matthias [STaRBURSTT-Cyberdiffraction Consortium, Department of Chemistry, Youngstown State University, One University Plaza, Youngstown, OH 44555-3663 (United States); Cullen, William [Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 (Canada); Witkowski, Mark [Food and Drug Administration, Forensic Chemistry Center, Vibrational Spectroscopy Laboratory, 6751 Steger Drive, Cincinnati, OH 45237 (United States); Creed, John [United States Environmental Protection Agency, National Exposure Research Laboratory, Microbiological and Chemical Exposure Assessment Research Division, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States)]. E-mail: creed.jack@epa.gov

    2007-01-30

    Dimethylthioarsinic acid (DMTA{sup V}) has recently been identified in biological, dietary and environmental matrices. The relevance of this compound to the toxicity of arsenic in humans is unknown and further exposure assessment and metabolic studies are difficult to conduct because of the unavailability of a well characterized standard. The synthesis of DMTA{sup V} was accomplished by the reaction of dimethylarsinic acid (DMA{sup V}) with hydrogen sulfide. The initial reaction product produced is DMTA{sup V} but multiple products over the course of the reaction are also observed. Therefore, a chromatographic separation was developed to monitor the reaction progress via LC-ICP-MS. In this synthesis, conversion of DMA{sup V} to DMTA{sup V} was not taken to completion to avoid the production of side products. The product was isolated from the starting material by standard organic techniques. Single crystal diffraction demonstrated that solid DMTA{sup V} is present in the form of the oxygen-bridged dimethylthioarsinic anhydride. Dissolution of the anhydride in water produces the acid form of DMTA{sup V} and the aqueous phase DMTA{sup V} provided a characteristic molecular ion of m/z 155 by LC-ESI-MS. The synthesis and isolation of dimethylthioarsinic anhydride provides a stable crystalline standard suitable for identification, toxicological study and exposure assessment of dimethylthioarsinic acid.

  4. Influence of different curing methods on the fatty acid composition in sausages prepared from red deer meat

    Directory of Open Access Journals (Sweden)

    Marek Šnirc

    2016-11-01

    Full Text Available These curing agents play a decisive role in obtaining the specific sensory properties, stability and hygienic safety of products such as fermented sausages, ham and, more recently, emulsion type of sausages. The effect of using two different curing agents (sodium chloride and nitrate on fatty acid compounds in dry-cured deer meat was investigated in our study. The concentration of free fatty acids in the fat depends on the hydrolytic activity of the lipases, the microbial metabolic processes, and the oxidative reactions that work on the free fatty acids released in the lipolysis. The main identified fatty acids in all different types of curing were palmitic acid (16 : 0, oleic acid (c18 : 1 cis-9, stearic acid (C18 : 0. The resulting n-6/n-3 PUFA ratio in the muscle samples of red deer showed no variation in different types of curing and was beneficially low within the range of 3.9 : 1 and 4.49 : 1. Total free fatty acids, whether saturated, monounsaturated or polyunsaturated fatty acids, did not increased (p >0.05 greatly through the processing of dry-cured deer meat. Also there was no effect of curing method on fatty acids composition in two different muscles Semitendinosus muscle (ANOVA, p >0.05, F - 0.003, F crit. - 3.041 and Triceps brachii muscle (ANOVA, p >0.05, F - 0.05, F crit. - 3.01. There were found no significant (p >0.05 differences between fatty acids content in sausages prepared by brining in NaCl and Nitrate salt. The present study revealed that game meat can function as a good source of bioactive compounds that are essential for human nutrition. 

  5. Poly(ester-anhydride):poly(beta-amino ester) micro- and nanospheres: DNA encapsulation and cellular transfection.

    Science.gov (United States)

    Pfeifer, Blaine A; Burdick, Jason A; Little, Steve R; Langer, Robert

    2005-11-04

    Poly(ester-anhydride) delivery devices allow flexibility regarding carrier dimensions (micro- versus nanospheres), degradation rate (anhydride versus ester hydrolysis), and surface labeling (through the anhydride functional unit), and were therefore tested for DNA encapsulation and transfection of a macrophage P388D1 cell line. Poly(l-lactic acid-co-sebacic anhydride) and poly(l-lactic acid-co-adipic anhydride) were synthesized through melt condensation, mixed with 25 wt.% poly(beta-amino ester), and formulated with plasmid DNA (encoding firefly luciferase) into micro- and nanospheres using a double emulsion/solvent evaporation technique. The micro- and nanospheres were then characterized (size, morphology, zeta potential, DNA release) and assayed for DNA encapsulation and cellular transfection over a range of poly(ester-anhydride) copolymer ratios. Poly(ester-anhydride):poly(beta-amino ester) composite microspheres (6-12 microm) and nanospheres (449-1031 nm), generated with copolymers containing between 0 and 25% total polyanhydride content, encapsulated plasmid DNA (>or=20% encapsulation efficiency). Within this polyanhydride range, poly(adipic anhydride) copolymers provided DNA encapsulation at an increased anhydride content (10%, microspheres; 10-25%, nanospheres) compared to poly(sebacic anhydride) copolymers (1%, microspheres and nanospheres) with cellular transfection correlating with the observed DNA encapsulation.

  6. Two Players Make a Formidable Combination: In Situ Generated Poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) Cross-Linking Gel Polymer Electrolyte toward 5 V High-Voltage Batteries.

    Science.gov (United States)

    Ma, Yue; Ma, Jun; Chai, Jingchao; Liu, Zhihong; Ding, Guoliang; Xu, Gaojie; Liu, Haisheng; Chen, Bingbing; Zhou, Xinhong; Cui, Guanglei; Chen, Liquan

    2017-11-29

    Electrochemical performance of high-voltage lithium batteries with high energy density is limited because of the electrolyte instability and the electrode/electrolyte interfacial reactivity. Hence, a cross-linking polymer network of poly(acrylic anhydride-2-methyl-acrylic acid-2-oxirane-ethyl ester-methyl methacrylate) (PAMM)-based electrolyte was introduced via in situ polymerization inspired by "shuangjian hebi", which is a statement in a traditional Chinese Kungfu story similar to the synergetic effect of 1 + 1 > 2. A poly(acrylic anhydride) and poly(methyl methacrylate)-based system is very promising as electrolyte materials for lithium-ion batteries, in which the anhydride and acrylate groups can provide high voltage resistance and fast ionic conductivity, respectively. As a result, the cross-linking PAMM-based electrolyte possesses a significant comprehensive enhancement, including electrochemical stability window exceeding 5 V vs Li + /Li, an ionic conductivity of 6.79 × 10 -4 S cm -1 at room temperature, high mechanical strength (27.5 MPa), good flame resistance, and excellent interface compatibility with Li metal. It is also demonstrated that this gel polymer electrolyte suppresses the negative effect resulting from dissolution of Mn 2+ ions at 25 and 55 °C. Thus, the LiNi 0.5 Mn 1.5 O 4 /Li and LiNi 0.5 Mn 1.5 O 4 /Li 4 Ti 5 O 12 cells using the optimized in situ polymerized cross-linking PAMM-based gel polymer electrolyte deliver stable charging/discharging profiles and excellent rate performance at room temperature and even at 55 °C. These findings suggest that the cross-linking PAMM is an intriguing candidate for 5 V class high-voltage gel polymer electrolyte toward high-energy lithium-on batteries.

  7. Method for curing alkyd resin compositions by applying ionizing radiation

    International Nuclear Information System (INIS)

    Watanabe, T.; Murata, K.; Maruyama, T.

    1975-01-01

    An alkyd resin composition is prepared by dissolving a polymerizable alkyd resin having from 10 to 50 percent of oil length into a vinyl monomer. The polymerizable alkyd resin is obtained by a half-esterification reaction of an acid anhydride having a polymerizable unsaturated group and an alkyd resin modified with conjugated unsaturated oil having at least one reactive hydroxyl group per one molecule. The alkyd resin composition thus obtained is coated on an article, and ionizing radiation is applied on the article to cure the coated film thereon. (U.S.)

  8. Inhibition of Listeria monocytogenes by propionic acid-based ingredients in cured deli-style Turkey.

    Science.gov (United States)

    Glass, Kathleen A; McDonnell, Lindsey M; Von Tayson, Roxanne; Wanless, Brandon; Badvela, Mani

    2013-12-01

    Listeria monocytogenes growth can be controlled on ready-to-eat meats through the incorporation of antimicrobial ingredients into the formulation or by postlethality kill steps. However, alternate approaches are needed to provide options that reduce sodium content but maintain protection against pathogen growth in meats after slicing. The objective of this study was to determine the inhibition of L. monocytogenes by propionic acid-based ingredients in high-moisture, cured turkey stored at 4 or 7°C. Six formulations of sliced, cured (120 ppm of NaNO2 ), deli-style turkey were tested, including control without antimicrobials, 3.2% lactate-diacetate blend (LD), 0.4% of a liquid propionate-benzoate-containing ingredient, or 0.3, 0.4, and 0.5% of a liquid propionate-containing ingredient. Products were inoculated with 5 log CFU L. monocytogenes per 100-g package (3 log CFU/ml rinsate), vacuum-sealed, and stored at 4 or 7°C for up to 12 weeks; and populations were enumerated by plating on modified Oxford agar. As expected, the control without antimicrobials supported rapid growth, with >2 log average per ml rinsate increase within 4 weeks of storage at 4°C, whereas growth was observed at 6 weeks for the LD treatment. For both replicate trials, all treatments that contained liquid propionate or propionate-benzoate limited L. monocytogenes growth to an increase of 1-log increase) was observed in individual samples for all propionate-containing treatments at weeks 10, 11, and 12. As expected, L. monocytogenes grew more rapidly when products were stored at 7°C, but trends in relative inhibition were similar to those observed at 4°C. These results verify that propionate-based ingredients inhibit growth of L. monocytogenes on sliced, high-moisture, cured turkey and can be considered as an alternative to reduce sodium-based salts while maintaining food safety.

  9. Eliminación del plomo por curado casero Lead elimination by traditional acidic curing

    Directory of Open Access Journals (Sweden)

    Luisa Torres-Sánchez

    1999-11-01

    Full Text Available Objetivo. Evaluar el curado ácido como medida preventiva para reducir el contenido de plomo en vasijas de barro vidriadas. Material y métodos. En 27 vasijas de barro procedentes de cuatro estados de México se determinó, mediante espectrofotometría de absorción atómica, el nivel de plomo residual, después de cuatro lavados con ácido acético al 3%. Resultados. El contenido de plomo en el ácido acético utilizado para lavar las vasijas disminuyó proporcionalmente con el número de lavados, aunque se conservó por arriba de los niveles permisibles (2.5-7.0 p.p.m.. Conclusiones. El curado ácido de piezas de barro no es una medida preventiva útil para reducir la exposición a plomo.Objective. To evaluate traditional acidic curing as a preventive method for reducing lead content of glazed ceramic ware. Material and methods. In 27 ceramic ware pieces from four states in Mexico, the level of residual lead was determined through atomic absorption spectrophotometry after four washings with acetic acid 3%. Results. The lead content of the vinegar washing diminished proportionally with the number of washings, although it remained highly above the permissible levels of this metal (2.5-7.0 p.p.m.. Conclusions. Traditional acidic curing of glazed ceramic ware is not a useful preventive measure for reducing lead exposure.

  10. Pt.3. Carbon-13 fractionation in the decomposition of formic acid initiated by phosphoric anhydride. 13C fractionation in the decomposition of HCOOH initiated by P2O5

    International Nuclear Information System (INIS)

    Zielinski, M.; Zielinska, A.

    1998-01-01

    13 C isotope effects in the decarbonylation of formic acid of natural isotopic composition initiated by phosphorus pentoxide have been studied in a large temperature range (-5 o C) - (+90 o C). The 13 C fractionation in the carbon monooxide production at -5 o C increased from a low value of 1.2% characteristic of the first fractions of consecutively controlled portions of carbon monooxide to higher values of 13 C KIE observed in the decarbonylation of pure formic acid at corresponding temperatures. The temperature and time dependences of the measured 13 C fractionation are functions of the relative number of milimoles of formic acid and the dehydrating phosphoric anhydride, P 2 O 5 . The addition of metaphosphoric acid reagent to unreacted formic acid containing H 3 PO 4 significantly increased the 13 C fractionation in subsequent decarbonylations at 70.4 o C but to a slightly less degree than expected ( 13 C KIE = 1.0503 instead 1.0535). The addition of metaphosphoric acid reagent to formic acid saturated with NaCl results in the experimental 13 C fractionation of the value of 1.0534 very close to the theoretical one. An explanation of the low values of 13 C KIE in the initial stages of HCOOH/P 2 O 5 decarbonylations has been presented. (author)

  11. Irradiation grafting of natural rubber latex with maleic anhydride and its compatibilization of poly(lactic acid)/natural rubber blends

    Science.gov (United States)

    Pongsathit, Siriwan; Pattamaprom, Cattaleeya

    2018-03-01

    Maleic anhydride (MA) is an interesting monomer to be grafted onto natural rubber(NR) due to its potential as a compatibilizer of hydrophobic rubbers and polymers with higher polarity. So far, radiation grafting of MA onto NR in latex state has not been reported. In this study, the grafting of NR with MA in latex state was investigated by exposing the latex to cobalt-60 gamma irradiation at a fixed MA content of 9% and a varied absorbed doses from 2 to 10 kGy. The FTIR spectrometer, 1H NMR spectrometer and gel content analysis have confirmed successful grafting of MA onto NR after irradiation. The grafted NRs were then used to increase the compatibility and the impact property of PLA/NR blends. It was found that the highest impact strength of the blends was achieved when the grafting was carried out at the absorbed dose of 4 kGy.

  12. Acid-curing and ferric-trickle leaching effluent used in closed circuit uranium extractive process

    International Nuclear Information System (INIS)

    Jin Suoqing; Xiang Qinfang; Guo Jianzheng; Lu Guizhu; Su Yanru

    1998-01-01

    The new uranium ore process consists of crushing ore, mixing crushed ore with strong acid in rotating drums and curing the mixture in piles, trickle-leaching the ore beds with ferric solution, extracting uranium from pregnant solution with tertiary amine, precipitating product and disposing residue tailings. All the process effluent is used in closed circuit. There will be no process water to be discharged in the flowsheet except the tailings carrying off 15% water because during leaching moisture content of the ore rises to 15%. Tailings produced by the process are moist and friable, and can be disposed of on a pile or returned to the mine. Main technical parameters of the process: (a) water consumption is 0.2∼0.3 m 3 /t ore, electric power consumption is 20∼30 kW·h/t ore; (b) ore crushing up to -5∼-7 mm, leaching period is 12∼45 d, U content of residue is 0.01%∼0.02%, producing pregnant solution is 0.3∼0.5 m 3 /t ore, which is 1/5∼1/8 that of conventional agitation leaching process; (c) organic agent consumption is 1/5∼1/8 that of the conventional agitation process. All the research results above are tested by the pilot-plant test and industrial test. The new process has been applied to recovery of uranium in the mine located at northeast of China

  13. Decoration of a Poly(methyl vinyl ether-co-maleic anhydride)-Shelled Selol Nanocapsule with Folic Acid Increases Its Activity Against Different Cancer Cell Lines In Vitro.

    Science.gov (United States)

    Ganassin, Rayane; Souza, Ludmilla Regina de; Py-Daniel, Karen Rapp; Longo, João Paulo Figueiró; Coelho, Janaína Moreira; Rodrigues, Mosar Correa; Jiang, Cheng-Shi; Gu, Jinsong; Morais, Paulo César de; Mosiniewicz-Szablewska, Ewa; Suchocki, Piotr; Báo, Sônia Nair; Azevedo, Ricardo Bentes; Muehlmann, Luis Alexandre

    2018-01-01

    Due to the low therapeutic index of different chemotherapeutic drugs used for cancer treatment, the development of new anticancer drugs remains an intense field of research. A recently developed mixture of selenitetriacylglycerides, selol, was shown to be active against different cancer cells in vitro. As this compound is highly hydrophobic, it was encapsulated, in a previous study, into poly(methyl vinyl ether-co-maleic anhydride)-shelled nanocapsules in order to improve its dispersibility in aqueous media. Following this line of research, the present report aimed at enhancing the In Vitro activity of the selol nanocapsules against cancerous cells by decorating their surface with folic acid. It is known that several cancer cells overexpress folate receptors. Stable folic acid-decorated selol nanocapsules (SNP-FA) were obtained, which showed to be spherical, with a hydro-dynamic diameter of 364 nm, and zeta potential of -24 mV. In comparison to non-decorated selol nanocapsules, SNP-FA presented higher activity against 4T1, MCF-7 and HeLa cells. Moreover, the decoration of the nanocapsules did not alter their toxicity towards fibroblasts, NIH-3T3 cells. These results show that the decoration with folic acid increased the toxicity of selol nanocapsules to cancer cells. These nanocapsules, besides enabling to disperse selol in an aqueous medium, increased the toxicity of this drug In Vitro, and may be useful to treat cancer in vivo, potentially increasing the specificity of selol towards cancer cells.

  14. Preparation of low viscosity epoxy acrylic acid photopolymer prepolymer in light curing system

    Science.gov (United States)

    Li, P.; Huang, J. Y.; Liu, G. Z.

    2018-01-01

    With the integration and development of materials engineering, applied mechanics, automatic control and bionics, light cured composite has become one of the most favourite research topics in the field of materials and engineering at home and abroad. In the UV curing system, the prepolymer and the reactive diluent form the backbone of the cured material together. And they account for more than 90% of the total mass. The basic properties of the cured product are mainly determined by the prepolymer. A low viscosity epoxy acrylate photosensitive prepolymer with a viscosity of 6800 mPa • s (25 °C ) was obtained by esterification of 5 hours with bisphenol A epoxy resin with high epoxy value and low viscosity.

  15. Identifying airway sensitizers: cytokine mRNA profiles induced by various anhydrides

    International Nuclear Information System (INIS)

    Plitnick, L.M.; Loveless, S.E.; Ladics, G.S.; Holsapple, M.P.; Smialowicz, R.J.; Woolhiser, M.R.; Anderson, P.K.; Smith, C.; Selgrade, M.J.K.

    2003-01-01

    Exposure to low molecular weight (LMW) chemicals in the workplace has been linked to a variety of respiratory effects. Within the LMW chemicals, one of the major classes involved in these effects are the acid anhydrides. The immunological basis of respiratory hypersensitivity involves CD4+ cells. By virtue of their induction of cytokines typical of CD4+ T-helper type 2 (Th2) cells--interleukin (IL)-4, 10, and 13--respiratory sensitizers may be identified and differentiated from contact sensitizers which induce Th1 cytokines (IL-2 and IFN-γ). Our previous work suggested that the ribonuclease protection assay (RPA) was useful in identifying the respiratory sensitizer, trimellitic anhydride (TMA), based on quantitative differences in Th2 cytokine mRNA as compared to the contact sensitizer dinitrochlorobenzene (DNCB). Therefore, the purpose of the studies described in this report was to expand the chemicals tested in the RPA. To this end, four acid anhydrides with known respiratory sensitization potential, TMA, maleic anhydride (MA), phthalic anhydride (PA) and hexahydrophthalic anhydride (HHPA), were tested. Although previously determined to induce immunologically equivalent responses in a local lymph node assay (LLNA), the initial dose chosen (2.5%) failed to induce Th2 cytokine mRNA expression. To determine if the lack of cytokine expression was related to dose, LLNAs were conducted at higher doses for each of the anhydrides. The highest doses evaluated (four- to six-fold higher than those used in the initial RPA) gave equivalent proliferative responses for the various anhydrides and were used for subsequent RPA testing. At these higher doses, significant increases in Th2 versus Th1 cytokine mRNA were observed for all anhydrides tested. These results suggest that the RPA has the potential to serve as a screen for the detection of LMW airway sensitizing chemicals. However, the basis for selecting immunologically equivalent doses may require some modification

  16. Sulfur amino acids in Cushing's disease: insight in homocysteine and taurine levels in patients with active and cured disease.

    Science.gov (United States)

    Faggiano, Antongiulio; Melis, Daniela; Alfieri, Raffaele; De Martino, MariaCristina; Filippella, Mariagiovanna; Milone, Francesco; Lombardi, Gaetano; Colao, Annamaria; Pivonello, Rosario

    2005-12-01

    Cushing's syndrome is associated with an increased cardiovascular risk. Although a series of cardiovascular risk factors have been identified, sulfur amino acids (SAAs), recently indicated as independent cardiovascular risk factors, have been poorly investigated in patients with Cushing's syndrome. The aim of this cross-sectional controlled study was to evaluate serum and urinary levels and urinary excretion rate (ER) of SAAs in patients with Cushing's disease (CD) during the active disease and after long-term disease remission. Forty patients with CD (20 with active disease and 20 with cured disease for at least 5 yr) and 40 controls entered the study. Serum and urinary concentrations and urinary ER of SAAs, namely methionine, cystine, homocysteine, and taurine, were measured by means of cationic exchange HPLC. Serum folic acid and vitamin B12 levels were also evaluated in patients and controls and correlated to SAA levels. CD patients with active disease had higher serum and urinary concentrations of cystine and homocysteine, and lower serum and higher urinary concentrations and ER of taurine than cured patients and controls. Vitamin B12 levels were significantly decreased in patients with active disease compared with cured patients and controls, whereas folic acid levels were slightly decreased in patients than in controls. In patients with active CD, urinary cortisol concentrations were significantly and inversely correlated to serum taurine and directly correlated to taurine urinary ER, and fasting serum glucose levels were significantly correlated to taurine urinary ER. At the multiple regression analysis, urinary cortisol concentrations were the best predictors of taurine ER. CD is associated with hyperhomocysteinemia and hypotaurinemia. Glucocorticoid excess, acting directly or indirectly, seems to be the most responsible for this imbalance in SAA levels. The long-term disease remission is accompanied by normalization of SAA levels. Hyperhomocysteinemia and

  17. Gastric ulcer treatment: cure of Helicobacter pylori infection without subsequent acid-suppressive therapy: is it effective?

    Science.gov (United States)

    van Zanten, Sander Veldhuyzen; van der Knoop, Bloeme

    2008-06-01

    Whether it is a requirement to continue with anti-secretory therapy following anti-Helicobacter therapy in H. pylori positive gastric ulcers is an important question. As gastric ulcers tend to heal more slowly than duodenal ulcers, may be asymptomatic or only causing mild symptoms and success at curing H. pylori with current fist line therapies is 80% at best, clinicians will likely err on the side of caution and continue acid suppressive therapy to ensure healing of gastric ulcers. This is certainly recommended when dealing with bleeding ulcers.

  18. Réaction du polyisobutène chloré sur l'anhydride maléique : mécanisme. Catalyse par l'anhydride dichloromaléique Reaction of Chlorinated Polyisobutene on Maleic Anhydride. Mechanism. Catalysis by Dichloromaleic Anhydride

    Directory of Open Access Journals (Sweden)

    Sillion B.

    2006-11-01

    Full Text Available Dans cet article le mécanisme de la réaction de condensation du polyisobutène chloré sur l'anhydride maléique, qui sert dans la synthèse d'additif pour lubrifiant, est étudié par une cinétique globale et par un travail sur composés modèles. Il est montré que, dans cette réaction, l'anhydride maléique joue un double rôle : de catalyseur de déshydrochloration par une réactivité de type acide de Lewis organique, de réactif comme diénophile. Grâce à ces résultats, il est proposé une catalyse par l'anhydride dichloromaléique, qui permet une amélioration sensible du procédé. This article examines the mechanism of the chlorinated-polyisobutene condensation reaction on maleic anhydride. The overall kinetics and model compounds are investigated for this reaction which is used in the synthesis of lubricant additives. Maleic anhydride is shown to play the dual role of a dehydrochlorination catalyst by having a reactivity of the organic Lewis acid type and of a reactant like dienophile. These results are used to propose a catalysis by dichloromaleic anhydride which appreciably improves the process.

  19. Extraction of uranium from coarse ore and acid-curing and ferric sulphate-trickle leaching process

    International Nuclear Information System (INIS)

    Jin Suoqing

    1994-01-01

    On the basis of analysis of the problems in the technology of the traditional uranium hydrometallurgy and the limitations of thin layer leaching process (TLL), a new leaching system-acid-curing and ferric sulphate-trickle leaching (AFL) process (NGJ in Chinese) has developed for extraction of uranium from the coarse ore. The ferric sulphate solution was used for trickling the acid-cured uranium ore and the residual leaching reaction incomplete in TLL process can be improved in this process. And the AFL process has a wide applicability to China's uranium ores, being in competition with the traditional agitation leaching process for treating coarse ores. The uranium ore processing technology based on the AFL process will become one of the new basic technologies of uranium hydrometallurgy. A series of difficulties will be basically overcome associated with fine grinding because of its elimination in the presented process. Moreover, the situation of the present uranium hydrometallurgy can be also changed owing to without technological effluent discharge

  20. Development of chitosan derivatives with anhydride maleic

    International Nuclear Information System (INIS)

    Silva, Solranny C.C.C.; Braz, Elton Marks de A.; Brito, Carla Adriana R. de S.; Silva, Durcilene A. da; Junior, Luiz de S.S.; Silva Filho, Edson C. da

    2015-01-01

    Chitosan was chemically modified with maleic anhydride in ratios of 1/2, 1/5 and 1/10 in the absence of solvents. The obtained derivatives were characterized by elemental analysis, FTIR, thermal analysis (TGA / DTG) and XRD where it was possible to prove the chemical modification. Elemental analysis showed an increase of the relation C / N with the increasing of the proportion of anhydrides. The FTIR showed the incorporation of the anhydride in the biopolymer structure. The thermal stability of the derivatives was lower in comparison to the polysaccharide and by XRD the modified materials were less crystalline. (author)

  1. Thermochemistry of sarcosine and sarcosine anhydride: Theoretical and experimental studies

    International Nuclear Information System (INIS)

    Amaral, Luísa M.P.F.; Santos, Ana Filipa L.O.M.; Ribeiro da Silva, Maria das Dores M.C.; Notario, Rafael

    2013-01-01

    Highlights: ► Study on the Energetics of the sarcosine and sarcosine anhydride. ► Experimental and computational thermochemistry of sarcosine and its anhydride. ► Ab initio calculations for two amino acid derivatives by G3(MP2)//B3LYP method. -- Abstract: The standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of sarcosine, −(388.0 ± 1.0) kJ · mol −1 , and sarcosine anhydride, −(334.5 ± 1.6) kJ · mol −1 , were calculated by combining, for each compound, the standard molar enthalpy of formation, in the crystalline phase, and the standard molar enthalpy of sublimation, derived from measurements of the standard massic energies of combustion by static bomb combustion calorimetry, and from measurements of vapour pressures by the Knudsen mass-loss effusion method, respectively. The standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs functions of sublimation, at T = 298.15 K, were also calculated. A theoretical study at the G3 and G4 levels has been carried out, and the calculated enthalpies of formation have been compared with the experimental ones

  2. Kaolinite Nanocomposite Platelets Synthesized by Intercalation and Imidization of Poly(styrene-co-maleic anhydride

    Directory of Open Access Journals (Sweden)

    Pieter Samyn

    2015-07-01

    Full Text Available A synthesis route is presented for the subsequent intercalation, exfoliation and surface modification of kaolinite (Kln by an imidization reaction of high-molecular weight poly(styrene-co-maleic anhydride or SMA in the presence of ammonium hydroxide. In a first step, the intercalation of ammonolyzed SMA by guest displacement of intercalated dimethylsulfoxide has been proven. In a second step, the imidization of ammonolyzed SMA at 160 °C results in exfoliation of the kaolinite layers and deposition of poly(styrene-co-maleimide or SMI nanoparticles onto the kaolinite surfaces. Compared with a physical mixture of Kln/SMI, the chemically reacted Kln/SMI provides more efficient exfoliation and hydrogen bonding between the nanoparticles and the kaolinite. The kaolinite nanocomposite particles are synthesized in aqueous dispersion with solid content of 65 wt %. The intercalation and exfoliation are optimized for a concentration ratio of Kln/SMI = 70:30, resulting in maximum intercalation and interlayer distance in combination with highest imide content. After thermal curing at 135 °C, the imidization proceeds towards a maximum conversion of the intermediate amic acid moieties. The changes in O–H stretching and kaolinite lattice vibrations have been illustrated by infrared and FT-Raman spectroscopy, which allow for a good quantification of concentration and imidization effects.

  3. A new process for the valorisation of a bio-alcohol. The oxidehydration of 1-butanol into maleic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Caldarelli, A.; Cavani, F.; Garone, O.; Pavarelli, G. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; Bologna Univ. (Italy). CIRCC, Research Unit; Dubois, J.L. [ARKEMA, Colombes (France); Mitsova, I.; Simeonova, L. [JSC, Russe (Bulgaria). Orgachim

    2012-07-01

    This paper deals with a study on the gas-phase transformation of 1-butanol into maleic anhydride, using different types of catalysts. Indeed, catalytic acid properties are needed to dehydrate 1-butanol into 1-butene, whereas redox-type properties are required for the oxidation of the olefin into maleic anhydride. The two types of active sites can be combined in bifunctional systems, showing both acid and redox-type properties. We found that vanadyl pyrophosphate catalyzes the one-pot reaction, giving a maximum selectivity to maleic anhydride of 28%. In fact, various side reactions contributed to the formation of by-products, eg, 1-butanol (oxidative) dehydrogenation into butyraldehyde, formation of light carboxylic acids and carbon oxides, and condensation of unsaturated C{sub 4} intermediates (butenes and butadiene) with the formed maleic anhydride to yield heavier compounds. (orig.)

  4. INTERRELATIONSHIP BETWEEN TEMPERATURE AND SODIUM CHLORIDE ON GROWTH OF LACTIC ACID BACTERIA ISOLATED FROM MEAT-CURING BRINES.

    Science.gov (United States)

    GOLDMAN, M; DEIBEL, R H; NIVEN, C F

    1963-05-01

    Goldman, Manuel (American Meat Institute Foundation, Chicago, Ill.), R. H. Deibel, and C. F. Niven, Jr. Interrelationship between temperature and sodium chloride on growth of lactic acid bacteria isolated from meat-curing brines. J. Bacteriol. 85:1017-1021. 1963.-An elevation of the temperature limit for growth of some Pediococcus homari (Gaffkya homari) and motile Lactobacillus strains could be effected by the addition of sodium chloride to the growth medium. At the optimal temperature for growth, sodium chloride was stimulatory, and as the temperature of incubation was increased a mandatory requirement for sodium chloride was manifested. At the optimal temperature for growth (30 C), the highest sodium chloride concentrations were tolerated; as the temperature was increased, this tolerance decreased, although the optimal sodium chloride concentration increased. No other substances were found that would replace the sodium chloride requirement at higher temperatures of incubation.

  5. Effect of processing variables on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted meat cured with sorbic acid and sodium nitrite.

    Science.gov (United States)

    Robach, M C

    1979-01-01

    The effects of the initial pH and a "short pump" on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted cured pork were studied. Fresh ground pork was cured with salt, sugar, phosphate, ascorbate, and varying amounts of sodium nitrite and sorbic acid. The product was comminuted and inoculated with 1,000 spores of C. sporogenes per g. The meat was stuffed into 1-ounce (ca. 28.4-g) aluminum tubes, cooked to 58.5 degrees C, cooled, and incubated at 27 degrees C to observe for swells. Product cured with 0.2% sorbic acid in combination with 40 ppm sodium nitrite (40 microgram/g) had better clostridium inhibition than did product cured with 120 ppm nitrite within a pH range of 5.0 to 6.7. The sorbic acid-40 ppm nitrite combination also gave better clostridial protection than did the 120 ppm nitrite alone when reduced amounts of curing ingredients were present. PMID:44445

  6. Effect of processing variables on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted meat cured with sorbic acid and sodium nitrite.

    Science.gov (United States)

    Robach, M C

    1979-11-01

    The effects of the initial pH and a "short pump" on the outgrowth of Clostridium sporogenes PA 3679 spores in comminuted cured pork were studied. Fresh ground pork was cured with salt, sugar, phosphate, ascorbate, and varying amounts of sodium nitrite and sorbic acid. The product was comminuted and inoculated with 1,000 spores of C. sporogenes per g. The meat was stuffed into 1-ounce (ca. 28.4-g) aluminum tubes, cooked to 58.5 degrees C, cooled, and incubated at 27 degrees C to observe for swells. Product cured with 0.2% sorbic acid in combination with 40 ppm sodium nitrite (40 microgram/g) had better clostridium inhibition than did product cured with 120 ppm nitrite within a pH range of 5.0 to 6.7. The sorbic acid-40 ppm nitrite combination also gave better clostridial protection than did the 120 ppm nitrite alone when reduced amounts of curing ingredients were present.

  7. Effect of expanded organoclay by stearic acid to curing, mechanical and swelling properties of natural rubber nanocomposites

    Science.gov (United States)

    Ramadhan, A.; Fathurrohman, M. Irfan; Falaah, A. F.; Setyawan, N.; Soegijono, B.

    2017-07-01

    The interlayer basal spacing of organoclay (OC) could be increased with stearic acid (SA) added, thus OC changed into expanded organoclay by SA (OCSA). The effect of various loadings of OCSA on the curing, mechanical and swelling properties of natural rubber (NR) nanocomposites were studied. The natural rubber/expanded organoclay (NR/OCSA) nanocomposites were prepared by melt intercalation using a laboratory open mill. The curing characteristics of NR compounds were determined using a Moving Die Rheometer (MDR). The X-ray Diffraction (XRD), Attenuated Total Reflectance Infrared (ATR-IR) Spectroscopy and Field Emission Scanning Electron Microscopy (FESEM) were used to study the dispersion of OCSA in the NR matrix. The mechanical properties of NR/OCSA nanocomposites such as tensile strength, elongation at break and hardness were determined using ISO standard and swelling of NR/OCSA nanocomposites in toluene were determined using ISO 1817. The results showed that the SA intercalated into the gallery of OC and reacted with the hydroxyl groups in OC. It was indicated with the shifting of the negative peak 1,700 to 1,723 cm-1 in the ATR-IR spectrum and increase the d-spacing of OC. The adding of various loadings of OCSA into NR could increase the torque and accelerate the curing of nanocomposites and it also could increase the mechanical and swelling properties of nanocomposites. The change in modulus at 100% elongation significantly increased with increasing the OCSA load until maximum loading at 10 phr. This trend was same with the hardness and modulus at 300% elongation. Meanwhile, the improvement of tensile strength and elongation at break was higher at 4 phr OCSA compared with the other loading. The increase of mechanical and swelling properties of NR/OCSA nanocomposites was due to intercalation/exfoliation of OCSA in NR matrix. It was revealed by appearing of the out-of-plane Si-O-(Al) stretch with peak value 1080 cm-1 in the ATR-IR spectrum and the peaks of OCSA

  8. Hydrolysis of Acetic Anhydride in a CSTR

    Directory of Open Access Journals (Sweden)

    Veronica N. Coraci

    2016-05-01

    Full Text Available To find the optimal reactor volume and temperature for the hydrolysis of acetic anhydride at the lowest possible cost with a 90% conversion of acetic anhydride, a formula for the total cost of the reaction was created. Then, the first derivative was taken to find a value for the temperature. This value was then inputted into the second derivative of the equation to find the sign of the value which would indicate whether that point was a minima or maxima value. The minima value would then be the lowest total cost for the optimum reaction to take place.

  9. Acceleration of curing period of pastrami manufactured from buffalo meat: II-Fatty acids, amino acids, nutritional value and sensory evaluation

    Directory of Open Access Journals (Sweden)

    Ibrahim, Hayam M.A.

    2001-04-01

    Full Text Available Upon accelerating the curing period of pastrami (dry cured meat prepared from buffalo lean round muscles using heat treatment (~71ºC internally, the results indicated that: the peroxide and thiobarbituric acid (TBA values increased with increasing the aging period. Percentage of the released free fatty acids was 1.21 after heat treatment and increased gradually to reach 1.47 after hanging in air at room temperature for drying and complete curing up to 6 days. The major saturated and unsaturated fatty acids in all of the pastrami samples were palmitic (16:0, oleic (18:1 and linoleic (18:2 fatty acids. The main three identified polyunsaturated fatty acids (linoleic, linolenic and arachidonic were of high percentages in the accelerated cured samples than in the control one. The ratio of the unsaturated: saturated fatty acids was similar in either the heat treated (1.28:1 and the control (1.27: 1 pastrami samples. Similar findings were found for the ratio of total essential amino acids (EAAS: total amino acids (AAS. The Essential Amino Acids Index (EAAI that possesses higher percentage for the heat treated sample than that for the control one proved the higher biological acceptance of the heat accelerated cured pastrami sample. The predicted protein efficiency ratio (PER of all the investigated samples reached more than 2.42 of casein. Sensory evaluation of the pastrami sample processed to an internal temperature of ~71ºC proved by the panelists to be of attractive color, more tasty, of good characteristic odor and more tender than the control samples which were prepared and cured for 3 weeks without using heat treatment.En relación a la aceleración del período de cura del pastrami (carne curada en seco preparada a partir de carne magra de búfalo usando un tratamiento térmico (~71ºC internamente, los resultados indicaron que los valores de peróxido y ácido tiobarbitúrico (TBA aumentaron con el envejecimiento. El porcentaje de

  10. Processing Pa-Lua Uranium ore by Mixing and Curing with Sulfuric Acid on a Scale of 500 kg/Batch to Recover Yellowcake

    International Nuclear Information System (INIS)

    Le Quang Thai; Cao Hung Thai; Le Thi Kim Dung; Phung Vu Phong; Tran Van Son

    2007-01-01

    Uranium ore in Pa-Lua area is sandstone with different levels of weathering. This kind of ore contains calcium and clay that may cause clogs during heap leaching. In this study, a technique of mixing and curing with strong acids is used and followed by washing to recover uranium. This study also focuses on study of ore processing issues such as crushing, regenerating particles in fine ores, mixing, curing and washing. The leach solution is treated by ion-exchange and precipitation of products by NH 4 OH. The experiment results show that regenerating a portion of fine ores, mixing and curing help washing residues in the column more effectively. Flow rate of the input solution can be controllable and stable. Columns do not clog even when washing takes place in the ore column of 5 meters high. Efficiency of uranium recovery can reach to 85-90%. Products of technical uranium are obtained with high quality. (author)

  11. Hydrolysis and stability of thin pulsed plasma polymerised maleic anhydride coatings

    DEFF Research Database (Denmark)

    Drews, Joanna Maria; Launay, Héléne; Hansen, Charles M.

    2008-01-01

    Abstract The stability of plasma polymerised layers has become important because of their widespread use. This study explored the hydrolysis and degradation stability of coatings of plasma polymerised maleic anhydride. Coatings made with different plasma parameters were exposed to aqueous media...... of different pH as a function of time. ATR-FTIR was used for structure analysis and a toluidine blue staining method allowed quantitative analysis of the hydrolysis of anhydride groups to acid groups. Coatings with constant thickness were obtained at different plasma powers and layers with varying thickness...

  12. Synthetic studies with Pinus elliottiis rosin derivatives. Oxidation of maleopimaric anhydride methyl ester and trimethyl fumaropimarate

    Directory of Open Access Journals (Sweden)

    Hess Sonia C.

    2000-01-01

    Full Text Available Ozonolysis of maleopimaric anhydride methyl ester in the presence of tetracyanoethylene led to an epoxide and an ozonide. Ozonolysis of the trimethyl fumaropimarate, followed by treatment with Me2S, led to an epoxide, a diene, a keto-acid and an allylic oxidation product. Some of the compounds obtained were active against Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus.

  13. Substituted Phthalic Anhydrides from Biobased Furanics : A New Approach to Renewable Aromatics

    NARCIS (Netherlands)

    Thiyagarajan, Shanmugam; Genuino, Homer C.|info:eu-repo/dai/nl/371571685; Sliwa, Michal; van der Waal, Jan C.; de Jong, Ed; van Haveren, Jacco; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397; Bruijnincx, Pieter C. A.|info:eu-repo/dai/nl/33799529X; van Es, Daan S.

    2015-01-01

    A novel route for the production of renewable aromatic chemicals, particularly substituted phthalic acid anhydrides, is presented. The classical two-step approach to furanics-derived aromatics via Diels-Alder (DA) aromatization has been modified into a three-step procedure to address the general

  14. Respiratory irritation by trimellitic anhydride in Brown Norway and Wistar rats

    NARCIS (Netherlands)

    Arts, J.H.E.; Koning, M.W.de; Bloksma, N.; Kuper, C.F.

    2001-01-01

    Several acid anhydrides are known for their sensitizing and irritative properties. Since both irritation and respiratory allergy can cause changes of lung function, proper testing of allergen-dependent effects on the respiratory tract requires knowledge of the respiratory irritant effects. To study

  15. Actinic-radiation curable polymers prepared from a reactive polymer, halogenated cyclic anhydride and glycidyl ester

    International Nuclear Information System (INIS)

    Pastor, S.D.

    1979-01-01

    A novel class of photosensitive polymers are disclosed which are prepared by the reaction, preferably in the presence of a catalyst, of a reactive polymer, a halogenated cyclic anhydride and glycidyl ester of an alpha, beta-unsaturated carboxylic acid. These polymers are capable of undergoing vinyl-type polymerization when exposed to actinic radiation

  16. Amino acid derivative-mediated detoxification and functionalization of dual cure dental restorative material for dental pulp cell mineralization.

    Science.gov (United States)

    Minamikawa, Hajime; Yamada, Masahiro; Iwasa, Fuminori; Ueno, Takeshi; Deyama, Yoshiaki; Suzuki, Kuniaki; Yawaka, Yasutaka; Ogawa, Takahiro

    2010-10-01

    Current dental restorative materials are only used to fill the defect of hard tissues, such as dentin and enamel, because of their cytotoxicity. Therefore, exposed dental pulp tissues in deep cavities must be first covered by a pulp capping material like calcium hydroxide to form a layer of mineralized tissue. However, this tissue mineralization is based on pathological reaction and triggers long-lasting inflammation, often causing clinical problems. This study tested the ability of N-acetyl cysteine (NAC), amino acid derivative, to reduce cytotoxicity and induce mineralized tissue conductivity in resin-modified glass ionomer (RMGI), a widely used dental restorative material having dual cure mechanism. Rat dental pulp cells were cultured on untreated or NAC-supplemented RMGI. NAC supplementation substantially increased the percentage of viable cells from 46.7 to 73.3% after 24-h incubation. Cell attachment, spreading, proliferative activity, and odontoblast-related gene and protein expressions increased significantly on NAC-supplemented RMGI. The mineralization capability of cells, which was nearly suppressed on untreated RMGI, was induced on NAC-supplemented RMGI. These improved behaviors and functions of dental pulp cells on NAC-supplemented RMGI were associated with a considerable reduction in the production of intracellular reactive oxygen species and with the increased level of intracellular glutathione reserves. These results demonstrated that NAC could detoxify and functionalize RMGIs via two different mechanisms involving in situ material detoxification and antioxidant cell protection. We believe that this study provides a new approach for developing dental restorative materials that enables mineralized tissue regeneration.

  17. Effect of the amount of chestnuts in the diet of Celta pigs on the fatty acid profile of dry-cured lacon

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, M.C. de; Dominguez, R.; Cantalapiedra, J.; Iglesias, A.; Lorenzo, J.M.

    2016-07-01

    The effect of including chestnuts in the formulation of the feed (0, 15 and 25% chestnut) on the fatty acids of dry-cured lacon from Celta pigs was studied. The inclusion of chestnuts decreases the saturated fatty acid content (SFA) and the monounsaturated fatty acid content (MUFA). With regards to the polyunsaturated fatty acids (PUFA), the lacon from animals fed with chestnuts presented higher values of total PUFA, n6 PUFAs and n3 PUFAs. This is related to the fact that chestnut diets had the highest amounts of essential fatty acids (C18:2n6 and C18:3n3), therefore the lacon from chestnut-fed animals also presented higher amounts of these fatty acids. According to nutritional ratios, lacon obtained from chestnut-fed pigs was healthier than the one obtained from pigs fed on commercial feed. The main conclusion is that including chestnuts in the diet allows us to obtain healthier dry-cured meat products. (Author)

  18. Increasing the electrical discharge endurance of acid anhydride cured DGEBA epoxy resin by dispersion of nanoparticle silica. High Perform. Polym. 11 (1999) pp 281-296 by IOP Publishing Ltd

    DEFF Research Database (Denmark)

    Henk, Peter O; Kortsen, T.W.; Kvarts, T.

    1999-01-01

    combinations were used: (a) fumed nanoparticle silicon dioxide referred to as Aerosil, (b) equal volumes of Aerosil and nanoparticle anatase, and (c) Aerosil plus anatase in combination with coarse-particle filler grade calcium-magnesium carbonate dolomite. A test for endurance using the CIGRE method II...... electrode arrangement was applied, the test comprising the establishment of partial discharges running perpendicularly onto one face of a plate specimen for a period measured until breakdown.Our results show that the endurance of the pure polymer is low. Increased loading with Aerosil increases...... the endurance by a factor of up to 20 as the Aerosil content goes from zero to 5.4 vol%. Aerosil mixed with anatase has a similar effect. The high level of endurance is maintained with an additional high-volume (35 vol.%) filling of coarse-particle dolomite to an epoxy system already containing Aerosil...

  19. Radiation curable coatings containing hydroxy functional polyethers and polyesters of monoethylenic acids or hydroxy esters thereof

    International Nuclear Information System (INIS)

    Kaufman, M.L.

    1978-01-01

    Relatively water insoluble hydroxy functional monoethylenic polyethers or polyesters of monoethylenic carboxylic acids or hydroxy alkyl esters thereof are formed by adducting the monoethylenic acid or its hydroxy ester with an anhydride selected from monoepoxides, lactones, or mixtures thereof in the presence of a Lewis acid catalyst, such as BF 3 etherate, at a temperature below that at which the unsaturation is consumed, typically about 30 to 70 0 C. These adducts are of low volatility and of low toxicity and can be radiation cured in admixture with polyacrylates to form coatings having improved resistance to elevated temperature exposure

  20. Effect of maleic anhydride on the physico-mechanical properties of NR/PE blends

    International Nuclear Information System (INIS)

    Yehia, A.A.; El Elnashar, D.

    2005-01-01

    Blending of two or more polymers is considered as a new technique to produce new materials with new properties at low production cost and investment. Rubber / Rubber blends are well known in tire industry. In the last decade rubber and plastic blending attract the interest of many researchers and technologists. In the present work NR and LLDPE was blended in presence of maleic anhydride (MA) on a Brabender premixed at different conditions and namely temperature and time. The obtained blends were cured with sulphur and peroxide curing systems. Peroxide can crosslink both NR and PE, but the sulphur system crosslinks only the rubber phase in the blend. The data showed also that the addition of MA greatly improved the physico-mechanical properties of NR/PE blends. The surface morphology of the blends under investigation was studied by SEM. The results will be presented and discussed in detail

  1. Accuracy of near infrared spectroscopy for prediction of chemical composition, salt content and free amino acids in dry-cured ham.

    Science.gov (United States)

    Prevolnik, Maja; Škrlep, Martin; Janeš, Lucija; Velikonja-Bolta, Spela; Škorjanc, Dejan; Čandek-Potokar, Marjeta

    2011-06-01

    The capability of near infrared (NIR) spectroscopy was examined for the purposes of quality control of the traditional Slovenian dry-cured ham "Kraški pršut." Predictive models were developed for moisture, salt, protein, non-protein nitrogen, intramuscular fat and free amino acids in biceps femoris muscle (n = 135). The models' quality was assessed using statistical parameters: coefficient of determination (R(2)) and standard error (se) of cross-validation (CV) and external validation (EV). Residual predictive deviation (RPD) was also assessed. Best results were obtained for salt content and salt percentage in moisture/dry matter (R(CV)(2)>0.90, RPD>3.0), it was satisfactory for moisture, non-protein nitrogen, intramuscular fat and total free amino acids (R(CV)(2) = 0.75-0.90, RPD = 2.0-3.0), while not so for protein content and proteolysis index (R(CV)(2) = 0.65-0.75, RPD<2.0). Calibrations for individual free amino acids yielded R(CV)(2) from 0.40 to 0.90 and RPD from 1.3 to 2.9. Additional external validation of models on independent samples yielded comparable results. Based on the results, NIR spectroscopy can replace chemical methods in quality control of dry-cured ham. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Radiation curing

    International Nuclear Information System (INIS)

    Wendrinsky, J.

    1987-04-01

    In the beginning of the seventies the two types of radiation sources applied in industrial processes, electron radiation and UV, had been given rather optimistic forecasts. While UV could succeed in the field of panel and film coating, electron radiation curing seems to gain success in quite new fields of manufacturing. The listing of the suggested applications of radiation curing and a comparison of both advantages and disadvantages of this technology are followed by a number of case studies emphasizing the features of these processes and giving some examplary calculations. The data used for the calculations should provide an easy calculation of individual manufacturing costs if special production parameters, investment or energy costs are employed. (Author)

  3. Maleic anhydride grafting on EPDM rubber in the melt

    NARCIS (Netherlands)

    Oostenbrink, A.J.; Oostenbrink, A.J.; Gaymans, R.J.

    1992-01-01

    The grafting of maleic anhydride on a EPDM rubber was studied with a twin screw extruder. The effect of barrel temperatures, throughput, maleic anhydride concentration and peroxide concentration [bis(t-butyl peroxy isopropyl)benzene] on the degree of grafting and melt viscosity was studied. The

  4. Urea- Hydrogen Peroxide (UHP Oxidation of Thiols to the Corresponding Disulfides Promoted by Maleic Anhydride as Mediator

    Directory of Open Access Journals (Sweden)

    M. H. Habibi

    2005-10-01

    Full Text Available Urea-hydrogen peroxide (UHP was used in the presence of maleic anhydride as mediator in a simple and convenient method for the oxidation in high yield of some thiols to the corresponding disulfides. Peroxymaleic acid formed in situ from the reaction of UHP with maleic anhydride has a key role in this oxidation. Performance of the reaction in various solvents showed that methanol was the solvent of choice at 0 oC. The products were isolated by simple filtration on silica gel.

  5. Synthesis and Characterization of Poly(maleic Anhydride)s Cross-linked Polyimide Aerogels

    Science.gov (United States)

    Guo, Haiquan; Meador, Mary Ann B.

    2015-01-01

    With the development of technology for aerospace applications, new thermal insulation materials are required to be flexible and capable of surviving high heat flux. For instance, flexible insulation is needed for inflatable aerodynamic decelerators which are used to slow spacecraft for entry, descent and landing (EDL) operations. Polyimide aerogels have low density, high porosity, high surface area, and better mechanical properties than silica aerogels and can be made into flexible thin films, thus they are potential candidates for aerospace needs. The previously reported cross-linkers such as octa(aminophenyl)silsesquioxane (OAPS) and 1,3,5-triaminophenoxybenzene (TAB) are either expensive or not commercially available. Here, we report the synthesis of a series of polyimide aerogels cross-linked using various commercially available poly(maleic anhydride)s, as seen in Figure 1. The amine end capped polyimide oligomers were made with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) and diamine combinations of dimethylbenzidine (DMBZ) and 4, 4-oxydianiline (ODA). The resulting aerogels have low density (0.12 gcm3 to 0.16 gcm3), high porosity (90) and high surface area (380-554 m2g). The effect of the different poly(maleic anhydride) cross-linkers and polyimide backbone structures on density, shrinkage, porosity, surface area, mechanical properties, moisture resistance and thermal properties will be discussed.

  6. Influence of cure of Helicobacter pylori infection on gastric acidity and gastroesophageal reflux: study by 24-h pH monitoring in patients with gastric or duodenal ulcer.

    Science.gov (United States)

    Fukuchi, Takumi; Ashida, Kiyoshi; Yamashita, Hiroshi; Kiyota, Naomi; Tsukamoto, Reiko; Takahashi, Hajime; Ito, Dai; Nagamatsu, Ryousuke

    2005-04-01

    Whether or not the eradication of Helicobacter pylori is a risk factor for reflux esophagitis (RE) is a question at issue. To find an answer, it is necessary to clarify the influence of H. pylori eradication on the mechanism of RE. The authors investigated the influence of H. pylori eradication on gastric acidity and gastroesophageal reflux in ten gastric ulcer (GU) patients and ten duodenal ulcer (DU) patients by 24-h simultaneous determination of pH in the stomach and esophagus. Though the results indicated enhanced gastric acidity in GU patients at night after H. pylori eradication, no such influence was observed in DU patients. No significant changes in gastroesophageal reflux occurred in GU or DU patients before and after H. pylori eradication. RE after H. pylori eradication occurred in only one patient, with GU. This patient had several risk factors for RE, such as obesity, male sex, and dietary habits to add to the increase in gastric acidity at night that occurred after H. pylori eradication. No increase in gastroesophageal reflux occurred in any DU patients or in the other GU patients that demonstrated enhanced gastric acidity at night after H. pylori eradication. The cure of H. pylori infection does not, by itself, cause RE in patients who have few other risk factors for RE.

  7. Effect of the amount of chestnuts in the diet of Celta pigs on the fatty acid profile of dry-cured lacon

    Directory of Open Access Journals (Sweden)

    de Jesús, M. C.

    2016-03-01

    Full Text Available The effect of including chestnuts in the formulation of the feed (0, 15 and 25% chestnut on the fatty acids of dry-cured lacon from Celta pigs was studied. The inclusion of chestnuts decreases the saturated fatty acid content (SFA and the monounsaturated fatty acid content (MUFA. With regards to the polyunsaturated fatty acids (PUFA, the lacon from animals fed with chestnuts presented higher values of total PUFA, n6 PUFAs and n3 PUFAs. This is related to the fact that chestnut diets had the highest amounts of essential fatty acids (C18:2n6 and C18:3n3, therefore the lacon from chestnut-fed animals also presented higher amounts of these fatty acids. According to nutritional ratios, lacon obtained from chestnut-fed pigs was healthier than the one obtained from pigs fed on commercial feed. The main conclusion is that including chestnuts in the diet allows us to obtain healthier dry-cured meat products.Se estudió el efecto de la inclusión de la castaña en la formulación del pienso (0, 15 y 25% de castaña sobre el perfil de ácidos grasos del lacón curado de cerdo Celta. La inclusión de castañas produjo una disminución del contenido de ácidos grasos saturados (SFA y monoinsaturados (MUFA. Con respecto a los ácidos grasos poliinsaturados (PUFA los lacones de animales alimentados por castaña presentaron valores más altos de PUFA totales, PUFA n6 y PUFA n3. Esto está relacionado con que las castañas tienen una mayor cantidad de ácidos grasos esenciales (C18:2n6 y C18:3n3, por tanto los lacones de cerdos alimentados con castaña también presentan mayores contenidos de estos ácidos grasos. De acuerdo con los índices nutricionales, los lacones obtenidos de cerdos alimentados con mayor proporción de castañas fueron más saludables. La inclusión de castañas en la dieta nos permite obtener productos cárnicos curados más saludables.

  8. Alternating copolymerization of epoxides with anhydrides initiated by organic bases

    Czech Academy of Sciences Publication Activity Database

    Hošťálek, Z.; Trhlíková, Olga; Walterová, Zuzana; Martinez, T.; Peruch, F.; Cramail, H.; Merna, J.

    2017-01-01

    Roč. 88, March (2017), s. 433-447 ISSN 0014-3057 Institutional support: RVO:61389013 Keywords : copolymerization * epoxides * anhydrides Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.531, year: 2016

  9. A novel reverse osmosis membrane modified by polyvinyl alcohol with maleic anhydride crosslinking

    Science.gov (United States)

    Samnani, Mohit; Rathod, Harshad; Raval, Hiren

    2018-03-01

    In the era of increasing energy crisis, it is inevitable to decrease process energy consumption to increase process viability and curtail green-house gas emission. The Reverse Osmosis plant requires significant energy to transfer water overcoming the osmotic pressure. This paper focuses on increasing the water flux for Thin Film Composite Reverse Osmosis (TFC RO) membrane without compromising salt rejection performance leading to the environmentally friendly and economically attractive process. The virgin TFC RO membrane was exposed to solution of sodium hypochlorite of concentration 2000 mg l-1 for 1 h to activate the surface of the membrane, followed by the treatment with the mixture of polyvinyl alcohol and maleic anhydride with varying concentrations for 1 h and curing in the oven at 80 °C temperature for 10 min. Out of all the treated membranes, the membrane treated with 2000 mg l-1 polyvinyl alcohol and 1000 mg l-1 maleic anhydride demonstrated the highest salt rejection of 96.83 % with 2% increase as compared to the virgin TFC RO membrane. The water flux of the membrane was around 44% higher than the virgin TFC RO membrane. The membrane samples were characterized by atomic force micrographs, ATR-FTIR, Nuclear magnetic resonance and Dynamic mechanical analysis.

  10. Air formaldehyde and solvent concentrations during surface coating with acid-curing lacquers and paints in the woodworking and furniture industry.

    Science.gov (United States)

    Thorud, Syvert; Gjolstad, Merete; Ellingsen, Dag G; Molander, Paal

    2005-06-01

    An investigation of contemporary exposure to formaldehyde and organic solvents has been carried out during surface coating with acid-curing lacquers and paints in the Norwegian woodworking and furniture industry over a period of 3 years. The investigation covered 27 factories of different sizes and with different types of production, and totally 557 parallel formaldehyde and solvent samples were collected. The formaldehyde concentration (geometric mean) was 0.15 ppm (range 0.01-1.48 ppm) with about 10% of the samples exceeding the Norwegian occupational exposure limit of 0.5 ppm. The solvent concentration as additive effect (geometric mean) was 0.13 (range 0.0004-5.08) and about 5% of the samples exceeded the Norwegian occupational exposure limit. The most frequently occurring solvents from acid-curing lacquers were n-butyl acetate, ethanol, ethyl acetate and 1-butanol, which were found in 88-98% of the samples. Toluene, n-butyl acetate and 1-butanol were the only solvents with maximum concentrations exceeding their respective occupational exposure limits. Curtain painting machine operators were exposed to the highest concentrations of both formaldehyde (geometric mean 0.51 ppm, range 0.08-1.48 ppm) and organic solvents (additive effect, geometric mean 1.18, range 0.02-5.08). Other painting application work tasks such as automatic and manual spray-painting, manual painting and dip painting, showed on average considerably lower concentrations of both formaldehyde (geometric means 0.07-0.16 ppm) and organic solvents (additive effect, geometric mean 0.02-0.18). Non-painting work tasks also displayed moderate concentrations of formaldehyde (geometric means 0.11-0.17 ppm) and organic solvents (additive effect, geometric mean 0.04-0.07).

  11. PDMS-modified poly(styrene-alt-maleic anhydride)s as water-borne coatings based on surfactant-free latexes

    NARCIS (Netherlands)

    Gunbas, I.D.; Wouters, M.E.L.; Benthem, R.A.T.M. van; Koning, C.E.; Noordover, B.A.J.

    2013-01-01

    In this work, two series of PDMS-modified poly(styrene-alt-maleic anhydride)s (PSMA) were prepared by the partial imidization of their anhydride groups with mono-functional, amine-terminated polydimethyl siloxanes (PDMS-NH2) with two different molecular weights. Subsequently, surfactant-free

  12. 3D Printing of Cytocompatible Water-Based Light-Cured Polyurethane with Hyaluronic Acid for Cartilage Tissue Engineering Applications

    Science.gov (United States)

    Shie, Ming-You; Chang, Wen-Ching; Wei, Li-Ju; Huang, Yu-Hsin; Chen, Chien-Han; Shih, Cheng-Ting; Chen, Yi-Wen; Shen, Yu-Fang

    2017-01-01

    Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is a limitation in the self-repair ability of the cartilage. Therefore, developing strategies for cartilage repair is very important. Here, we report on a new liquid resin preparation process of water-based polyurethane based photosensitive materials with hyaluronic acid with application of the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton’s jelly mesenchymal stem cells (hWJMSCs) and the cells in this case showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and also facilitate the development of cartilage tissue engineering. PMID:28772498

  13. 3D Printing of Cytocompatible Water-Based Light-Cured Polyurethane with Hyaluronic Acid for Cartilage Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Ming-You Shie

    2017-02-01

    Full Text Available Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is a limitation in the self-repair ability of the cartilage. Therefore, developing strategies for cartilage repair is very important. Here, we report on a new liquid resin preparation process of water-based polyurethane based photosensitive materials with hyaluronic acid with application of the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton’s jelly mesenchymal stem cells (hWJMSCs and the cells in this case showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and also facilitate the development of cartilage tissue engineering.

  14. One-pot synthesis of thermoplastic mixed paramylon esters using trifluoroacetic anhydride.

    Science.gov (United States)

    Shibakami, Motonari; Tsubouchi, Gen; Sohma, Mitsugu; Hayashi, Masahiro

    2015-03-30

    Mixed paramylon esters prepared from paramylon (a storage polysaccharide of Euglena), acetic acid, and a long-chain fatty acid by one-pot synthesis using trifluoroacetic anhydride as a promoter and solvent were shown to have thermoplasticity. Size exclusion chromatography indicated that the mixed paramylon esters had a weight average molecular weight of approximately 4.9-6.7×10(5). Thermal analysis showed that these esters were stable in terms of the glass transition temperature (>90°C) and 5% weight loss temperature (>320°C). The degree of substitution of the long alkyl chain group, a dominant factor determining thermoplasticity, was controlled by tuning the feed molar ratio of acetic acid and long-chain fatty acid to paramylon. These results implied that the one-pot synthesis is useful for preparing structurally-well defined thermoplastic mixed paramylon esters with high molecular weight. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Crystallo-chemistry of boric anhydride and of anhydrous borates

    International Nuclear Information System (INIS)

    Bernardin, Jacques

    1968-01-01

    After an overview of various aspects related to the atomic structure of boron and of its three-bind and four-bind compounds, this report briefly presents the different forms of boric anhydride (in solid, liquid, glassy and gaseous state), presents and comments the structure of these different forms, and addresses the molten boric anhydride which is used as oxide solvent. The next part addresses the structure of anhydrous borates. It presents some generalities on their structure, and describes examples of known structures: dimers, trimers, polymers with a degree higher than three like calcium metaborate, caesium tri-borate, lithium tetraborate, or potassium pentaborate

  16. Selective hydrogenation of maleic anhydride over Pd/Al2O3 ...

    Indian Academy of Sciences (India)

    Keywords. Pd/Al2O3 catalyst; maleic anhydride; selective hydrogenation; succinic anhydride. 1. Introduction ... attracted a significant amount of attention because the majority of its ... added, and the colour of the resulting mixture turned brown.

  17. 78 FR 76567 - Tall Oil, Polymer With Polyethylene Glycol and Succinic Anhydride Monopolyisobutylene Derivs...

    Science.gov (United States)

    2013-12-18

    ..., Polymer With Polyethylene Glycol and Succinic Anhydride Monopolyisobutylene Derivs.; Tolerance Exemption... an exemption from the requirement of a tolerance for residues of tall oil, polymer with polyethylene..., polymer with polyethylene glycol and succinic anhydride monopolyisobutylene derivs. on food or feed...

  18. Epoxy/anhydride thermosets modified with end-capped star polymers with poly(ethyleneimine cores of different molecular weight and poly(ε–caprolactone arms

    Directory of Open Access Journals (Sweden)

    C. Acebo

    2015-09-01

    Full Text Available Multiarm star polymers, with a hyperbranched poly(ethyleneimine (PEI core and poly(ε-caprolactone (PCL arms end-capped with acetyl groups were synthesized by ring-opening polymerization of ε-caprolactone from PEI cores of different molecular weight. These star polymers were used as toughening agents for epoxy/anhydride thermosets. The curing process was studied by calorimetry, thermomechanical analysis and infrared spectroscopy. The final properties of the resulting materials were determined by thermal and mechanical tests. The addition of the star polymers led to an improvement up to 130% on impact strength and a reduction in the thermal stresses up to 55%. The structure and molecular weight of the modifier used affected the morphology of the resulting materials. Electron microscopy showed phase-separated morphologies with nano-sized fine particles well adhered to the epoxy/anhydride matrix when the higher molecular weight modifier was used.

  19. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Styrene-maleic anhydride copolymers. 177.1820 Section 177.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use...

  20. Radiation curing of polymers

    International Nuclear Information System (INIS)

    Randell, D.R.

    1987-01-01

    The contents of this book are: Areas of Application of UV Curing; Areas of Application of EB Curing; Laser Curing of Acrylic Coatings; A User's View of the Application of Radiation Curable Materials; Radiation Curable Offset Inks: A Technical and Marketing Overview; and UV Curable Screen Printing Inks

  1. Effect of pasture on chestnut or acorn on fatty acid composition and aromatic profile of fat of Cinta Senese dry-cured ham

    Directory of Open Access Journals (Sweden)

    Franci, Oreste

    2009-07-01

    Full Text Available The objective of this study was to evaluate the effect of pasture on oak and chestnut grove on chemical and aromatic traits of Cinta Senese cured ham. Fifteen Cinta Senese barrows (124 kg of l.w. on average were allotted to three groups: one group (MI was reared outdoors in confined area and fed commercial feedstuff. The other two groups were raised under free-range conditions on acorn (AC or chestnut (CH woods. At slaughtering (148 kg of l.w. the right thighs were seasoned for 360 days, on average, to obtained cured hams. Results demonstrated that subcutaneous fat of ham of CH and AC groups, respect to CONC group, was the richest in MUFA (51.3 and 53.9 vs 49.5% respectively, because of the higher content of oleic acid (48.4 and 50.8 vs 46.2%, respectively. AC showed a lower percentage of PUFA than CH and CONC (13.8 vs 15.4 and 16.3%, respectively. As regard volatile compounds, AC, respect to CH and MI groups, showed the highest value of aldehydes (44.1 vs 30.3 and 33.5% respectively and ethers (4.04 vs 1.15 and 1.71% respectively.El objetivo de este estudio fue la evaluación de la composición de los ácidos grasos y de los compuestos volátiles del jamón curado Toscano obtenido de cerdos Cinta Senese alimentados con bellota, castaña o pienso. Quince cerdos de raza Cinta Senese fueron criados en extensivo: 5 fueron criados en bosque de bellota (AC, 5 en bosque de castaña (CH y 5 en un cercado y alimentados con pienso (MI. El día posterior al sacrificio se curaron los jamones. La composición de los ácidos grasos fue estadísticamente diferente entre los tipos de alimentación. La grasa de AC presentó el mayor porcentaje de AGMI total en comparación con CH y MI (51.3 y 53.9 vs 49.5% respectivamente gracias al mayor porcentaje de ácido oleico (48.4 y 50.8 vs 46.2%, respectivamente, y la menor de AGPI total (13.8 vs 15.4 y 16.3%, respectivamente. En relación a los compuestos volátiles, la grasa de AC, en comparación con CH y MI

  2. Highly Efficient Gas-Phase Oxidation of Renewable Furfural to Maleic Anhydride over Plate Vanadium Phosphorus Oxide Catalyst.

    Science.gov (United States)

    Li, Xiukai; Ko, Jogie; Zhang, Yugen

    2018-02-09

    Maleic anhydride (MAnh) and its acids are critical intermediates in chemical industry. The synthesis of maleic anhydride from renewable furfural is one of the most sought after processes in the field of sustainable chemistry. In this study, a plate vanadium phosphorus oxide (VPO) catalyst synthesized by a hydrothermal method with glucose as a green reducing agent catalyzes furfural oxidation to MAnh in the gas phase. The plate catalyst-denoted as VPO HT -has a preferentially exposed (200) crystal plane and exhibited dramatically enhanced activity, selectivity and stability as compared to conventional VPO catalysts and other state-of-the-art catalytic systems. At 360 °C reaction temperature with air as an oxidant, about 90 % yield of MAnh was obtained at 10 vol % of furfural in the feed, a furfural concentration value that is much higher than those (<2 vol %) reported for other catalytic systems. The catalyst showed good long-term stability and there was no decrease in activity or selectivity for MAnh during the time-on-stream of 25 h. The high efficiency and catalyst stability indicate the great potential of this system for the synthesis of maleic anhydride from renewable furfural. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Electron beam-cured coating

    International Nuclear Information System (INIS)

    Kishi, Naoyuki

    1976-01-01

    The method for hardening coatings by the irradiation with electron beams is reviewed. The report is divided into seven parts, namely 1) general description and characteristics of electron beam-cured coating, 2) radiation sources of curing, 3) hardening conditions and reaction behaviour, 4) uses and advantages, 5) latest trends of the industry, 6) practice in the field of construction materials, and 7) economy. The primary characteristics of the electron beam hardening is that graft reaction takes place between base resin and coating to produce strong adhesive coating without any pretreatment. A variety of base resins are developed. High class esters of acrylic acid monomers and methacrylic acid monomers are mainly used as dilutants recently. At present, scanning type accelerators are used, but the practical application of the system producing electron beam of curtain type is expected. The dose rate dependence, the repetitive irradiation and the irradiation atmosphere are briefly described. The filed patent applications on the electron beam hardening were analyzed by the officer of Japan Patent Agency. The production lines for coatings by the electron beam hardening in the world are listed. In the electron beam-cured coating, fifty percent of given energy is consumed effectively for the electron beam hardening, and the solvents discharged from ovens and polluting atmosphere are not used, because the paints of high solid type is used. The running costs of the electron beam process are one sixth of the thermal oven process. (Iwakiri, K.)

  4. Blends of nitrile butadiene rubber/poly (vinyl chloride: The use of maleated anhydride castor oil based plasticizer

    Directory of Open Access Journals (Sweden)

    Indiah Ratna Dewi

    2016-06-01

    Full Text Available Recently, much attention has been focused on research to replace petroleum-based plasticizers, with biodegradable materials, such as biopolymer which offers competitive mechanical properties. In this study, castor oil was modified with maleic anhydride (MAH to produce bioplasticizer named maleated anhydride castor oil (MACO, and used in nitrile butadiene rubber (NBR/poly vinyl chloride (PVC blend. The effect of MACO on its cure characteristics and mechanical properties of NBR/PVC blend has been determined. The reactions were carried out at different castor oil (CO/xylene ratios, i.e. 1:0 and 1:1 by weight, and fixed CO/MAH ratio, 1:3 by mole. DOP, CO, and MACO were added into each NBR/PVC blend according to the formula. It was found that the viscosity and safe process level of NBR/PVC blend is similar from all plasticizer, however, MACO (1:0 showed the highest cure rate index (CRI. MACO-based plasticizer gave a higher value of the mechanical properties of the NBR/PVC blend as compared to DOP based plasticizer. MACO (1:1 based plasticizer showed a rather significance performance compared to another type of plasticizers both before and after aging. The value of hardness, elongation at break, tensile strength, and tear strength were 96 Shore A, 155.91 %, 19.15 MPa, and 74.47 MPa, respectively. From this result, NBR/PVC blends based on MACO plasticizer can potentially replace the DOP, and therefore, making the rubber blends eco-friendly.

  5. Composite cements benefit from light-curing.

    Science.gov (United States)

    Lührs, Anne-Katrin; De Munck, Jan; Geurtsen, Werner; Van Meerbeek, Bart

    2014-03-01

    To investigate the effect of curing of composite cements and a new ceramic silanization pre-treatment on the micro-tensile bond strength (μTBS). Feldspathic ceramic blocks were luted onto dentin using either Optibond XTR/Nexus 3 (XTR/NX3; Kerr), the silane-incorporated 'universal' adhesive Scotchbond Universal/RelyX Ultimate (SBU/RXU; 3M ESPE), or ED Primer II/Panavia F2.0 (ED/PAF; Kuraray Noritake). Besides 'composite cement', experimental variables were 'curing mode' ('AA': complete auto-cure at 21°C; 'AA*': complete auto-cure at 37°C; 'LA': light-curing of adhesive and auto-cure of cement; 'LL': complete light-curing) and 'ceramic surface pre-treatment' ('HF/S/HB': hydrofluoric acid ('HF': IPS Ceramic Etching Gel, Ivoclar-Vivadent), silanization ('S': Monobond Plus, Ivoclar-Vivadent) and application of an adhesive resin ('HB': Heliobond, Ivoclar-Vivadent); 'HF/SBU': 'HF' and application of the 'universal' adhesive Scotchbond Universal ('SBU'; 3M ESPE, only for SBU/RXU)). After water storage (7 days at 37°C), ceramic-dentin sticks were subjected to μTBS testing. Regarding the 'composite cement', the significantly lowest μTBSs were measured for ED/PAF. Regarding 'curing mode', the significantly highest μTBS was recorded when at least the adhesive was light-cured ('LA' and 'LL'). Complete auto-cure ('AA') revealed the significantly lowest μTBS. The higher auto-curing temperature ('AA*') increased the μTBS only for ED/PAF. Regarding 'ceramic surface pre-treatment', only for 'LA' the μTBS was significantly higher for 'HF/S/HB' than for 'HF/SBU'. Complete auto-cure led to inferior μTBS than when either the adhesive (on dentin) or both adhesive and composite cement were light-cured. The use of a silane-incorporated adhesive did not decrease luting effectiveness when also the composite cement was light-cured. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Grafting and curing

    International Nuclear Information System (INIS)

    Garnett, J.L.; Loo-Teck Ng; Visay Viengkhou

    1998-01-01

    Progress in radiation grafting and curing is briefly reviewed. The two processes are shown to be mechanistically related. The parameters influencing yields are examined particularly for grafting. For ionising radiation grafting systems (EB and gamma ray) these include solvents, substrate and monomer structure, dose and dose-rate, temperature and more recently role of additives. In addition, for UV grafting, the significance of photoinitiators is discussed. Current applications of radiation grafting and curing are outlined. The recent development of photoinitiator free grafting and curing is examined as well as the potential for the new excimer laser sources. The future application of both grafting and curing is considered, especially the significance of the occurrence of concurrent grafting during cure and its relevance in environmental considerations

  7. Designing maleic anhydride-{alpha}-olifin copolymeric combs as wax crystal growth nucleators

    Energy Technology Data Exchange (ETDEWEB)

    Soni, Hemant P. [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390 002 (India); Kiranbala; Bharambe, D.P. [Department of Applied Chemistry, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara-390 001 (India); Agrawal, K.S. [Department of Petrochemical Technology, Polytechnic, The Maharaja Sayajirao University of Baroda, Vadodara-390 002 (India); Nagar, A. [MH ASSET, ONGC, Mumbai (India)

    2010-09-15

    Modification of the wax crystal habit is of great practical interest during transportation and processing of crude oil at low temperature. Various pour point depressant (PPD) additives can facilitate this modification by different mechanisms. Comb shaped polymer additives are known to depress the pour point of crude oil by providing different nucleation sites for the precipitation of wax. This paper describes performance based design, synthesis, characterization and evaluation of comb shaped polymeric diesters. Copolymers of maleic anhydride with different unsaturated C{sub 22} esters were synthesized and copolymers then reacted with two unsaturated fatty alcohols. All products were characterized by Fourier Transform Infra Red (FTIR) spectroscopy and Gel Permeation Chromatography (GPC). Rheological properties of crude (with and without additive) were studied by Advance Rheometer AR-500. In this study the additive based on oleic acid was evaluated as good PPD and rheology modifier. (author)

  8. Effect of Hops Beta Acids on the Survival of Unstressed- or Acid-Stress-Adapted-Listeria Monocytogenes and on the Quality and Sensory Attributes of Commercially Cured Ham Slices.

    Science.gov (United States)

    Wang, Li; McKeith, Amanda Gipe; Shen, Cangliang; Carter, Kelsey; Huff, Alyssa; McKeith, Russell; Zhang, Xinxia; Chen, Zhengxing

    2016-02-01

    This study evaluated the antilisterial activity of hops beta acids (HBA) and their impact on the quality and sensory attributes of ham. Commercially cured ham slices were inoculated with unstressed- and acid-stress-adapted (ASA)-L. monocytogenes (2.2 to 2.5 log CFU/cm(2) ), followed by no dipping (control), dipping in deionized (DI) water, or dipping in a 0.11% HBA solution. This was followed by vacuum or aerobic packaging and storage (7.2 °C, 35 or 20 d). Samples were taken periodically during storage to check for pH changes and analyze the microbial populations. Color measurements were obtained by dipping noninoculated ham slices in a 0.11% HBA solution, followed by vacuum packaging and storage (4.0 °C, 42 d). Sensory evaluations were performed on ham slices treated with 0.05% to 0.23% HBA solutions, followed by vacuum packaging and storage (4.0 °C, 30 d). HBA caused immediate reductions of 1.2 to 1.5 log CFU/cm(2) (P ham slices. During storage, the unstressed-L. monocytogenes populations on HBA-treated samples were 0.5 to 2.0 log CFU/cm(2) lower (P color or sensory attributes of the ham slices stored in vacuum packages. These results are useful for helping ready-to-eat meat processors develop operational procedures for applying HBA on ham slices. © 2016 Institute of Food Technologists®

  9. Poly(anhydride-co-imides): in vivo biocompatibility in a rat model.

    Science.gov (United States)

    Ibim, S M; Uhrich, K E; Bronson, R; El-Amin, S F; Langer, R S; Laurencin, C T

    1998-05-01

    The degradation and tissue compatibility characteristics of a novel class of biodegradable poly(anhydride-co-imide) polymers: poly[trimellitylimidoglycine-co-1,6-bis(carboxyphenoxy)hexan e] (TMA-gly: CPH) (in 10:90; 30:70 and 50: 50 molar ratios) and poly[pyromellitylimidoalanine-co-1,6-bis(carboxyphenoxy)hexa ne] (PMA-ala:CPH) (in 10:90 and 30:70 molar ratios) were investigated and compared with control poly(lactic acid/glycolic acid) (PLAGA in 50:50 molar ratio) matrices, a well-characterized biocompatible polymer, in rat subcutaneous tissues for 60 days. Polymers were compression-molded into circular discs of 14 mm x 1 mm in diameter. On post-operative days 7, 14, 28 and 60, histological tissue samples were removed, prepared by fixation and staining, and analyzed by light microscopy. PLAGA matrices produced mild inflammatory reactions and were completely degraded at the end of 60 days, leaving implant tissues that were similar to surgical wounds without implants. TMA-gly:CPH (10:90 and 30:70) matrices produced mild inflammatory reactions by the end of 60 days, similar to those seen with PLAGA. TMA-gly: CPH (50: 50) produced moderate inflammatory reactions characterized by macrophages and edema. PMA-ala:CPH matrices elicited minimal inflammatory reactions that were characterized by fibrous encapsulation by the end of 60 days. In vivo degradation rates of poly(anhydride-co-imides) were similar to PLAGA. Both PMA-ala:CPH and TMA-gly: CPH matrices maintained their shapes and degraded at a constant rate over the period of two months. These polymers, possessing good mechanical properties and tissue compatibility, may be useful in weight-bearing applications in bone.

  10. Rubber curing chemistry governing the orientation of layered silicate

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The effect of curing systems on the orientation and the dispersion of the layered silicates in acrylonitrile butadiene rubber nanocomposite is reported. Significant differences in X-ray diffraction pattern between peroxide curing and sulfur curing was observed. Intense X-ray scattering values in the XRD experiments from peroxide cured vulcanizates indicate an orientation of the layers in a preferred direction as evinced by transmission electron micrographs. However, sulfur cured vulcanizates show no preferential orientation of the silicate particles. Nevertheless, a closer inspection of transmission electron microscopy (TEM images of peroxide and sulfur cured samples shows exfoliated silicate layers in the acrylonitrile butadiene rubber (NBR matrix. It was revealed in the prevailing study that the use of an excess amount of stearic acid in the formulation of the sulfur curing package leads to almost exfoliated type X-ray scattering pattern.

  11. Chemical radiolabeling of carboxyatractyloside by [14C]acetic anhydride

    International Nuclear Information System (INIS)

    Block, M.R.; Pougeois, R.; Vignais, P.V.

    1980-01-01

    The authors report the synthesis and biological properties of a radiolabeled derivative of CAT obtained with acetylation of the primary alcohol of CAT with radiolabeled acetic anhydride. They also investigate the question of mutual exclusion of CAT and BA for binding to the mitochondrial ADP/ATP carrier in double labeling experiments based on the use of [ 3 H]BA and [ 14 C]Ac-CAT. The results are consistent with the view that the ADP/ATP carrier possesses two separate interacting binding sites for AT (or CAT) and for BA. (Auth.)

  12. C-CURE

    Data.gov (United States)

    US Agency for International Development — C-CURE system manages certain aspects of the access control system, including collecting employee and contractor names and photographs. The Office of Security uses...

  13. Efficient synthesis of zinc-containing mesoporous silicas by microwave irradiation method and their high activities in acetylation of 1,2-dimethoxybenzene with acetic anhydride

    Directory of Open Access Journals (Sweden)

    K. Bachari

    2016-09-01

    Full Text Available A series of acid zinc-containing mesoporous materials have been synthesized by microwave irradiation method with different Si/Zn ratios (Si/Zn = 100, 65, 15 and characterized by several spectroscopic techniques such as: N2 physical adsorption, ICP, XRD, TEM, FT-IR and a temperature-programmed-desorption (TPD of pyridine. The liquid phase of acetylation of 1,2-dimethoxybenzene with acetic anhydride has been investigated over this series of catalysts. In fact, the catalyst Zn-JLU-15 (15 showed bigger performance in the acid-catalyzed acetylation of 1,2-dimethoxybenzene employing acetic anhydride as an acylating agent. Furthermore, the kinetics of the acetylation of 1,2-dimethoxybenzene over these catalysts have also been investigated.

  14. Initiation precursors and initiators in laser-induced copolymerization of styrene and maleic anhydride in acetone

    Science.gov (United States)

    Miner, Gilda A.; Meador, Willard E.; Chang, C. Ken

    1990-01-01

    The initiation step of photopolymerized styrene/maleic anhydride copolymer was investigated at 365 nm. UV absorption measurements provide decisive evidence that the styrene/maleic anhydride charge transfer complex is the sole absorbing species; however, key laser experiments suggest intermediate reactions lead to a monoradical initiating species. A mechanism for the photoinitiation step of the copolymer is proposed.

  15. Additive effects in radiation grafting and curing

    International Nuclear Information System (INIS)

    Viengkhou, V.; Ng, L.

    1996-01-01

    Full text: Detailed studies on the accelerative effect of novel additives in radiation grafting and curing using acrylated monomer/oligomer systems have been performed in the presence of ionising radiation and UV as sources. Methyl methacrylate (MMA) is used as typical monomer for these grafting studies in the presence of the additives with model backbone polymers, cellulose and propropylene. Additives which have been found to accelerate these grafting processes are: mineral acid, occlusion compounds like urea, thermal initiators and photoinitiators as well as multifunctional monomers such as multifunctional acrylates. The results from irradiation with gamma rays have also been compared with irradiation from a 90W UV lamp. The role of the above additives in accelerating the analogous process of radiation curing has been investigated. Acrylated urethanes, epoxies and polyesters are used as oligomers together with acrylated monomers in this work with uv lamps of 300 watts/inch as radiation source. In the UV curing process bonding between film and substrate is usually due to physical forces. In the present work the presence of additives are shown to influence the occurrence of concurrent grafting during cure thus affecting the nature of the bonding of the cured film. The conditions under which concurrent grafting with UV can occur will be examined. A mechanism for accelerative effect of these additives in both grafting and curing processes has been proposed involving radiation effects and partitioning phenomena

  16. Radiation curing - a personal perspective

    International Nuclear Information System (INIS)

    Pappas, S.P.

    1992-01-01

    This chapter briefly introduces radiation curing from the personal perspective of the author. Topics covered in this chapter include characteristic features of radiation curing, photoinitiated polymerization -- ultraviolet (UV) curing, and general principles of electron beam (EB) curing. 57 refs., 2 tabs

  17. Radiation curing in the eighties

    International Nuclear Information System (INIS)

    Vrancken, A.

    1984-01-01

    The subject is discussed under the headings: introduction; what is radiation curing; history; radiation curable resins (with properties of products); ultraviolet and electron beam curing; photoinitiation and the ultraviolet light curing process; electron beam curing (initiation; electron beam accelerators); end uses (graphic arts; wood finishing; paper upgrading; adhesives; metal finishing; electronic chemical; floor coatings). (U.K.)

  18. Barrier and adhesion properties of anti-corrosion coatings based on surfactant-free latexes from anhydride-containing polymers

    NARCIS (Netherlands)

    Soer, W.J.; Ming, W.; Koning, C.E.; Benthem, van R.A.T.M.; Mol, J.M.C.; Terryn, H.

    2009-01-01

    We have successfully obtained surfactant-free latexes from anhydride-containing polymers, including poly(styrene-alt-maleic anhydride) (PSMA), maleinized polybutadiene (PBDMA), and poly(octadecene-alt-maleic anhydride) (POMA). Here we report barrier and adhesion properties of the coatings made from

  19. Preliminary in vivo report on the osteocompatibility of poly(anhydride-co-imides) evaluated in a tibial model.

    Science.gov (United States)

    Ibim, S E; Uhrich, K E; Attawia, M; Shastri, V R; El-Amin, S F; Bronson, R; Langer, R; Laurencin, C T

    1998-01-01

    A novel class of polymers with mechanical properties similar to cancellous bone are being investigated for their ability to be used in weight-bearing areas for orthopedic applications. The poly(anhydride-co-imide) polymers based on poly[trimellitylimidoglycine-co-1,6-bis(carboxyphenoxy)hexan e] (TMA-Gly:CPH) and poly[pyromellitylimidoalanine-co-1,6-bis(carboxyphenoxy)hexa ne] (PMA-Ala:CPH) in molar ratios of 30:70 were investigated for osteocompatibility, with effects on the healing of unicortical 3-mm defects in rat tibias examined over a 30-day period. Defects were made with surgical drill bits (3-mm diameter) and sites were filled with poly(anhydride-co-imide) matrices and compared to the control poly(lactic acid-glycolic acid) (PLAGA) (50:50), a well-characterized matrix frequently used in bone regeneration studies, and defects without polymeric implants. At predetermined time intervals (3, 6, 9, 12, 20, and 30 days), animals were sacrificed and tissue histology was examined for bone formation, polymer-tissue interaction, and local tissue response by light microscopy. The studies revealed that matrices of TMA-Gly:CPH and PMA-Ala:CPH produced responses similar to the control PLAGA with tissue compatibility characterized by a mild response involving neutrophils, macrophages, and giant cells throughout the experiment for all matrices studied. Matrices of PLAGA were nearly completely degraded by 21 days in contrast to matrices of TMA-Gly:CPH and PMA-Ala:CPH that displayed slow erosion characteristics and maintenance of shape. Defects in control rats without polymer healed by day 12, defects containing PLAGA healed after 20 days, and defects containing poly(anhydride-co-imide) matrices produced endosteal bone growth as early as day 3 and formed bridges of cortical bone around matrices by 30 days. In addition, there was marrow reconstitution at the defect site for all matrices studied along with matured bone-forming cells. This study suggests that novel poly(anhydride

  20. Synthesis and characterization of Trichloroisocyanouric acid ...

    Indian Academy of Sciences (India)

    Abstract. Trichloroisocyanouric acid (TCCA)-functionalized mesoporous silica nanocomposites (SBA/ .... 1 mmol of acetic anhydride and a suitable solvent were taken in a ..... washed with methanol, water and finally with acetone. The dried ...

  1. Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure

    Science.gov (United States)

    Liu, Y.; Bai, X.; Liu, Y.W.; Wang, Y.

    2015-01-01

    Light cure is a popular mode of curing for dental adhesives. However, it suffers from inadequate light delivery when the restoration site is less accessible, in which case a self-cure mechanism is desirable to salvage any compromised polymerization. We previously reported a novel self-cure system mediated by ethyl 4-(dimethylamino)-benzoate (4E) and hydroxyapatite (HAp). The present work aims to investigate if such self-cure phenomenon takes place in adhesives that underwent prior inadequate light cure and to elucidate if HAp released from the dental etching process is sufficient to trigger it. Model self-etch adhesives were formulated with various components, including bis[2-methacryloyloxy)ethyl]-phosphate (2MP) as acidic monomer and trimethylbenzoyl-diphenylphosphine oxide (TPO) as photoinitiator. In vitro evolution of degree of conversion (DC) of HAp-incorporated adhesives was monitored by infrared spectroscopy during light irradiation and dark storage. Selected adhesives were allowed to etch and extract HAp from enamel, light-cured in situ, and stored in the dark, after which Raman line mapping was used to obtain spatially resolved DC across the enamel-resin interface. Results showed that TPO+4E adhesives reached DC similar to TPO-only counterparts upon completion of light irradiation but underwent another round of initiation that boosted DC to ~100% regardless of HAp level or prior light exposure. When applied to enamel, TPO-only adhesives had ~80% DC in resin, which gradually descended to ~50% in enamel, whereas TPO+4E adhesives consistently scored ~80% DC across the enamel-resin interface. These observations suggest that polymerization of adhesives that underwent insufficient light cure is salvaged by the novel self-cure mechanism, and such salvaging effect can be triggered by HAp released from dental substrate during the etching process. PMID:26635279

  2. Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure.

    Science.gov (United States)

    Liu, Y; Bai, X; Liu, Y W; Wang, Y

    2016-03-01

    Light cure is a popular mode of curing for dental adhesives. However, it suffers from inadequate light delivery when the restoration site is less accessible, in which case a self-cure mechanism is desirable to salvage any compromised polymerization. We previously reported a novel self-cure system mediated by ethyl 4-(dimethylamino)-benzoate (4E) and hydroxyapatite (HAp). The present work aims to investigate if such self-cure phenomenon takes place in adhesives that underwent prior inadequate light cure and to elucidate if HAp released from the dental etching process is sufficient to trigger it. Model self-etch adhesives were formulated with various components, including bis[2-methacryloyloxy)ethyl]-phosphate (2MP) as acidic monomer and trimethylbenzoyl-diphenylphosphine oxide (TPO) as photoinitiator. In vitro evolution of degree of conversion (DC) of HAp-incorporated adhesives was monitored by infrared spectroscopy during light irradiation and dark storage. Selected adhesives were allowed to etch and extract HAp from enamel, light-cured in situ, and stored in the dark, after which Raman line mapping was used to obtain spatially resolved DC across the enamel-resin interface. Results showed that TPO+4E adhesives reached DC similar to TPO-only counterparts upon completion of light irradiation but underwent another round of initiation that boosted DC to ~100% regardless of HAp level or prior light exposure. When applied to enamel, TPO-only adhesives had ~80% DC in resin, which gradually descended to ~50% in enamel, whereas TPO+4E adhesives consistently scored ~80% DC across the enamel-resin interface. These observations suggest that polymerization of adhesives that underwent insufficient light cure is salvaged by the novel self-cure mechanism, and such salvaging effect can be triggered by HAp released from dental substrate during the etching process. © International & American Associations for Dental Research 2015.

  3. Beam in on curing

    International Nuclear Information System (INIS)

    Holl, Dr.

    1981-01-01

    Electron beam curing of paints and allied materials is discussed. Examples of applications are: silicone papers; painting of metal; bonding of flake adhesives; bonding of grinding media (binders); paints for external uses; painting shaped parts; bi-reactive painting systems. An example is given of the calculation of the cost of irradiation. (U.K.)

  4. Curing the queue

    NARCIS (Netherlands)

    Zonderland, Maartje Elisabeth

    2012-01-01

    In this dissertation we study several problems related to the management of healthcare and the cure of disease. In each chapter a hospital capacity distribution problem is analyzed using techniques from operations research, also known as mathematical decision theory. The problems considered are

  5. Development of chitosan derivatives with anhydride maleic; Desenvolvimento de derivados de quitosana com anidrido maleico

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Solranny C.C.C.; Braz, Elton Marks de A.; Brito, Carla Adriana R. de S.; Silva, Durcilene A. da; Junior, Luiz de S.S.; Silva Filho, Edson C. da, E-mail: solbiologa@hotmail.com [Universidade Federal do Piaui (UFPI), Teresina, PI (Brazil)

    2015-07-01

    Chitosan was chemically modified with maleic anhydride in ratios of 1/2, 1/5 and 1/10 in the absence of solvents. The obtained derivatives were characterized by elemental analysis, FTIR, thermal analysis (TGA / DTG) and XRD where it was possible to prove the chemical modification. Elemental analysis showed an increase of the relation C / N with the increasing of the proportion of anhydrides. The FTIR showed the incorporation of the anhydride in the biopolymer structure. The thermal stability of the derivatives was lower in comparison to the polysaccharide and by XRD the modified materials were less crystalline. (author)

  6. Cure of skin cancer. Surgical cure of skin cancer

    International Nuclear Information System (INIS)

    Zikiryakhodjaev, D.Z.; Sanginov, D.R.

    2001-01-01

    In this chapter authors studied the cure of skin cancer in particular the surgical cure of skin cancer. They noted that surgical cure of skin cancer is remain one of the primary and most important methods in treatment of skin cancer

  7. Controlled Release of Damascone from Poly(styrene-co-maleic anhydride-based Bioconjugates in Functional Perfumery

    Directory of Open Access Journals (Sweden)

    Andreas Herrmann

    2013-02-01

    Full Text Available Poly(styrene-co-maleic anhydrides were modified with poly(propylene oxide (PO-co-ethylene oxide (EO side chains (Jeffamine® with different EO/PO molar ratios, varying between 0.11 and 3.60. These copolymers were then further functionalized with a β-mercapto ketone of δ-damascone. The obtained poly(maleic acid monoamide-based β-mercapto ketones were then studied as delivery systems for the controlled release of δ-damascone by retro 1,4-addition. The release of δ-damascone, a volatile, bioactive molecule of the family of rose ketones, was studied by dynamic headspace analysis above a cotton surface after deposition of a cationic surfactant containing fabric softening formulation, as a function of the ethylene oxide (EO/propylene oxide (PO molar ratio of the grafted copolymer side chains. The polarity of the EO/PO side chain influenced the release efficiency of the damascone in a typical fabric softening application. PO-rich copolymers and the corresponding poly(styrene-co-maleic anhydride without Jeffamine® side chains were found to be less efficient for the desired fragrance release than the corresponding bioconjugate with a EO/PO ratio of 3.60 in the side chain. This copolymer conjugate seemed to represent a suitable balance between hydrophilicity and hydrophobicity to favor the release of the δ-damascone and to improve the deposition of the conjugate from an aqueous environment onto a cotton surface.

  8. What is radiation curing

    International Nuclear Information System (INIS)

    Kinstle, J.F.

    1975-01-01

    Radiation curing is a highly interdisciplinary and sophisticated field. Successful interplay between chemists and engineers of various disciplines is required. Throughout the research-development-applications cycle, two disciplines for which hybridization is extremely important are radiation chemistry and polymer chemistry. The molecular level effects caused by absorbed radiation depend strongly on the type and intensity of the radiation. Efficient utilization of the radiation to effect desired transformations in a monomer and/or polymer system, and maximization of final properties, depend on well-planned polymer synthesis and system formulation. The elementary basis of these two disciplines and the manner in which they necessarily coalesce in the field of radiation curing are reviewed

  9. Beam in on curing

    International Nuclear Information System (INIS)

    Holl, Dr.

    1981-01-01

    This third part of an article on the electron beam curing of paints covers the following aspects: inertising equipment; working without inert gas; increase in temperature when irradiating; irradiating plants; laboratory plants; plant operating from coil to coil; plant for shaped parts; possible applications; decorative films, paper, PVC; packaging material; metallisation of paper films; film bonding; strengthening of flock; coating; pressure sensitive adhesives. (U.K.)

  10. Distance to Cure

    OpenAIRE

    Capachi, Casey

    2013-01-01

    Distance to Cure A three-part television series by Casey Capachi www.distancetocure.com   Abstract   How far would you go for health care? This three-part television series, featuring two introductory segments between each piece, focuses on the physical, cultural, and political obstacles facing rural Native American patients and the potential of health technology to break down those barriers to care.   Part one,Telemedici...

  11. A fully coupled diffusion-reaction scheme for moisture sorption-desorption in an anhydride-cured epoxy resin

    KAUST Repository

    El Yagoubi, Jalal; Lubineau, Gilles; Roger, Frederic; Verdu, Jacques

    2012-01-01

    Thermoset materials frequently display non-classical moisture sorption behaviors. In this paper, we investigated this issue from an experimental point of view as well as in terms of modeling the water transport. We used the gravimetric technique to monitor water uptake by epoxy samples, with several thicknesses exposed to different levels of humidity during absorption and desorption tests. Our results revealed that the polymer displays a two-stage behavior with a residual amount of water that is desorbed progressively. We proposed a phenomenological reaction-diffusion scheme to describe this behavior. The model describes water transport as a competition between diffusion and the reaction, during which the local diffusivity and solubility depend on the local advancement of the reaction. We then implemented our model using COMSOL Multiphysics and identified it using a MATLAB-COMSOL optimization tool and the experimental data. We discussed the relation between the hydrophilicity of the product of the reaction and the diffusion behavior. We examined the reaction-induced modification of the water concentration field. It is worth noting that part of the phenomenology can be explained by the presence of hydrolyzable groups. © 2012 Elsevier Ltd. All rights reserved.

  12. A fully coupled diffusion-reaction scheme for moisture sorption-desorption in an anhydride-cured epoxy resin

    KAUST Repository

    El Yagoubi, Jalal

    2012-11-01

    Thermoset materials frequently display non-classical moisture sorption behaviors. In this paper, we investigated this issue from an experimental point of view as well as in terms of modeling the water transport. We used the gravimetric technique to monitor water uptake by epoxy samples, with several thicknesses exposed to different levels of humidity during absorption and desorption tests. Our results revealed that the polymer displays a two-stage behavior with a residual amount of water that is desorbed progressively. We proposed a phenomenological reaction-diffusion scheme to describe this behavior. The model describes water transport as a competition between diffusion and the reaction, during which the local diffusivity and solubility depend on the local advancement of the reaction. We then implemented our model using COMSOL Multiphysics and identified it using a MATLAB-COMSOL optimization tool and the experimental data. We discussed the relation between the hydrophilicity of the product of the reaction and the diffusion behavior. We examined the reaction-induced modification of the water concentration field. It is worth noting that part of the phenomenology can be explained by the presence of hydrolyzable groups. © 2012 Elsevier Ltd. All rights reserved.

  13. An efficient acetylation of dextran using in situ activated acetic anhydride with iodine

    Directory of Open Access Journals (Sweden)

    MUHAMMAD A. HUSSAIN

    2010-02-01

    Full Text Available A facile, efficient, cost-effective and solvent-free acetylation method has been developed for the acetylation of dextran. Dextran acetates were successfully synthesized using different molar ratios of acetic anhydride in the presence of iodine as a catalyst without the use of any solvent. The reactions were realized at 50 °C for 3 h under stirring and nitrogen. This efficient method yielded highly pure and organosoluble dextran esters. The reaction appears highly effective for obtaining higher degrees of substitution (DS with great efficiency. Under solvent-free conditions, dextran triacetates were efficiently synthesized. It was also observed that the molar ratio can easily control the DS of pendant groups onto the polymer backbone. Hence, a range of products with varying DS were successfully designed, purified and characterized. Covalent attachment of the pendant groups onto the polymer backbone was verified by spectroscopic techniques. Thermogravimetric analysis indicated that the obtained dextran esters were thermally as stable as dextran. The DS of the pendant groups onto the polymer backbone was calculated using standard acid base titration after saponification. Furthermore, all products were thoroughly characterized by thermal analysis (TG and DTG, and FTIR and 1H-NMR spectroscopic analysis.

  14. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride

    International Nuclear Information System (INIS)

    Li, Conghu; Tian, Zhenhua; Liu, Wentao; Li, Guoying

    2015-01-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen. - Highlights: • Acylated collagen retained the unique triple helix conformation. • Acylated collagen had stronger thermostability than native collagen. • Amide I was the most sensitive band to the temperature for acylated collagen. • Amide II was the most sensitive band to the temperature for native collagen. • Auto-peak at 1680 cm −1 for acylated collagen disappeared at higher temperature

  15. In vivo conjugation of nasal lavage proteins by hexahydrophthalic anhydride

    International Nuclear Information System (INIS)

    Johannesson, Gunvor; Lindh, Christian; Nielsen, Joern; Bjoerk, Birgitta; Rosqvist, Seema; Joensson, Bo A.G.

    2004-01-01

    Hexahydrophthalic anhydride (HHPA), an industrially important chemical, is a highly allergenic compound. The aim of this work was to identify proteins in nasal lavage fluid (NLF) that form adducts with HHPA. Such bindings may induce production of specific immunoglobulin E (IgE) or affect physiological mechanisms of the proteins. NLF was obtained from HHPA-exposed volunteers, workers and exposed guinea pigs. HHPA-binding proteins were visualized with immunoblotting using a polyclonal antiserum against HHPA. The proteins were excised from sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, digested with trypsin and identified by tandem mass spectrometry (MS/MS) and database searches. The antiserum was found to be specific for HHPA-bound proteins. In vivo formed HHPA-binding proteins in humans were identified as antileukoproteinase, immunoglobulin G (IgG), immunoglobulin A (IgA), serum albumin and lactoferrin. In addition, several proteins binding to HHPA were found in NLFs from guinea pigs but these could not be identified from database searches. Hypotheses for development of airways diseases by adduction of this allergenic compound to the NLF proteins in humans were established

  16. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    DEFF Research Database (Denmark)

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben

    2010-01-01

    Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...... acid has been derivatised with the anhydride form of phenyl succinic acid (PheSA). The fluorescence of PheSA was efficiently quenched by the HA matrix. HA also acted as a singlet oxygen scavenger. Fluorescence lifetime(s) of PheSA in solution and when attached to the HA matrix has been monitored...

  17. [Nonnius and the Spa cure].

    Science.gov (United States)

    Lecomte, J; Lemli, J; Marganne, M H; Melard, M

    1996-01-01

    The 12th of July 1635, Jan van Beverwyck wrote a letter from Dordrecht to his esteemed friend Luis Nunez, in Antwerp. He asked him for indications about the cure of kidney stones of which he was suffering. He had just passed two calculi very painfully. Nunez answered on July 31. His letter summarized his own experience with this disease. In such cases, temperate diuretics and emollients are well indicated: ingestion of light decoctions of Malva and Viola, Caerefolium and Parieteria as well as Marshmallow syrup. No purge and no 'chemicals'. However, the best remedy was drinking Spa water. Usually the best way to absorb it is to come to the springs, in the Ardennes, part of the independent Principality of Liège. However, considering the horrors of the war (the Thirty Years War) endangering the country, van Beverwyck would be wise to drink imported water during 40 or 50 days, while staying home quietly, in Dordrecht. The letter points out the importance of provoked diuresis in the treatment of kidney stones. On the other hand the letter is an illustration of the continuing contacts between the United Provinces and the Spanish territories and of the commercial traffic between Antwerp, Dordrecht and Spa. The exported water was bottled from many 'pouhons'. It was acid, ferruginous, sulfurous and saturated with carbon dioxide; no pathogen germs, at least at the spring. Nunez quoted the large number of his patients cured with Spa water in Antwerp. This is an illustration of its commercial expansion even during this critical period.

  18. [A case report: anomaly of the fourth branchial pouch with recurring cervical abscesses. Cauterization with trichloroacetic acid closed the fistula opening and cured the patient].

    Science.gov (United States)

    Stenquist, Monika; Juhlin, Claes; Aström, Gunnar; Friberg, Ulla

    2003-04-24

    A fourth branchial pouch sinus is a rare congenital anomaly, which in a 13-year-old girl presented clinically as recurrent deep cervical abscesses. The location of the majority of these anomalies is the left side of the neck (90%). Radiological and endoscopic investigations verified the diagnosis. The internal orifice located at the apex of the pyriform sinus could facilitate contamination by infectious pharyngeal secretions and lead to abscess recurrence. Traditionally, the recommended treatment is radical surgery. It can, however, be technically difficult to excise the whole fistula tract. In this patient we used a non-invasive treatment modality; chemocauterization with 40% trichloroacetic acid (TCA). After three treatments the fistula was closed. To date (month no. 15) there has been no abscess recurrence. TCA chemocauterization seems to be a safe first-line treatment for patients with pyriform sinus fistulas.

  19. Leprosy: eradication or cure?

    Science.gov (United States)

    Kakar, S

    1995-01-01

    The National Leprosy Eradication Program (NLEP), launched in 1986, has brought medicine for leprosy to more people than ever before, covering 200 of India's 455 districts. Since 1988, the number of leprosy patients discharged as cured each year has been greater than the number of newly detected, thus moving the country closer to its goal of eradicating leprosy from India. A substantial number of the 3 million people with leprosy in India are likely to come under the coverage of the NLEP. The author, however, argues that the fight against leprosy and the NLEP should be considered in their historical context. Leprosy is therefore used to illustrate how the perhaps interchangeable terms eradication and cure are charged with history and custom. Historically, the focus on eradicating leprosy has had terrible consequences for the patient. In England, perceptions about leprosy are relevant to the situation India, for colonial policy on leprosy was largely derivative. In the 1880s, especially, leprosy excited the public imagination. Asylums adopted segregation and confinement during this period for people with leprosy and the colonial government in India supported that approach from 1882. The author concludes that while the NLEP is laudable, the program must not focus upon eradicating leprosy. It should instead focus upon the leprosy patient, who has for so long been denied and discriminated against. The individual must be placed at the center of any program. Some steps in this direction have been taken.

  20. The effect of gamma radiation on the ageing of sulfur cured nr/csm and nbr/csm rubber blends reinforced by carbon black

    Directory of Open Access Journals (Sweden)

    Gordana Marković

    2009-10-01

    Full Text Available In this work the effect of the γ-radiation dose on ageing of carbon black reinforced elastomeric materials was studied. The compounds based on natural rubber/chlorosulfonated rubber blend (NR/CSM and butadiene acrylonitrile rubber/chlorosulfonated rubber blend (NBR/CSM (50:50, w/w with different loadings (0, 20, 40, 50, 60, 80 and 100 phr of the filler with the average particle size of 40 nm were cured by sulfur. The obtained elastomeric composites were subjected to radiation doses (100, 200, 300 and 400 kGy in the presence of oxygen. The changes of material mechanical properties were estimated after radiation accelerated ageing. By using Fourier transform infrared measurements (ATR-FTIR it was assessed that after exposure to doses of 100 kGy alcohols, ethers, lactones, anhydrides, esters and carboxylic acids are formed in materials. The formation of shorter polyene sequences and aromatic rings in aged samples are assumed on the basis of the obtained spectra.

  1. C-11 Acid and the Stereochemistry of Abietic Acid

    Indian Academy of Sciences (India)

    IAS Admin

    While many features, like the phenanthrene-type of fusion of the three ... thought to contain the original ring A of abietic acid, retaining the. 'nuclear methyl .... Thinking that the anhydride he had obtained by the action of heat on the C-11 acid ...

  2. Properties of radiation cured coatings

    International Nuclear Information System (INIS)

    Larson, E.G.; Spencer, D.S.; Boettcher, T.E.; Melbauer, M.A.; Skarjune, R.P.

    1987-01-01

    Coatings were prepared from acrylate or methacrylate functionalized resins to study the effect of end group functionality on the physical properties of u.v. and electron beam cured coatings. Cure response was measured by solid state NMR and gel extraction, as expected, methacrylate resins cured much slower. Thermal Gravimetric Analysis (TGA) revealed acrylate coatings have greater thermal stability. Properties such as tensile strength and hardness showed little effect of end group functionality or curing method. The O 2 and H 2 O permeabilities of the coating were correlated with the processing conditions. (author)

  3. The situation of radiation curing

    International Nuclear Information System (INIS)

    Chen Weixiu

    1988-01-01

    Radiation curing is a branch of radiation processing. It has developed significantly and its annual growth rate exceeds 10% in the nineteen eighties. Several products were manufactured by radiation curing, such as magnetic media, release coating, floor tile, printing flates, optical fiber, electronics, lithography and pressure sensitive adhesives etc. The chemistry of radiation curing is often considered ahead. The safe handling of UV/EB curable material, the regulation of industial and the patent protection for development in radiation curing were introduced. The equipment and processes of this field have got progress recently

  4. Syntheses of {gamma}-aminobutyric-1-{sup 14}C and of {alpha}-aminoadipic-6-{sup 14}C acid from methoxy-3 chloropropyl-magnesium and marked carbon dioxide; Syntheses de l'acide {gamma}-aminobutyrique{sup 14}C-1 et de l'acide {alpha}-aminoadipique {sup 14}C-6 a partir de methoxy-3 chloropropylmagnesium et d'anhydride carbonique marque

    Energy Technology Data Exchange (ETDEWEB)

    Liem, Phung Nhu [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires, Departement des radioelements, Service des molecules marquees

    1967-04-01

    Carbonation of {gamma}-methoxypropyl-magnesium chloride by CO{sub 2} gives {gamma}-methoxy-butyric carboxylic-{sup 14}C acid with a yield of about 95 per cent. When the latter is treated successively with anhydrous HBr and with diazomethane, methyl carboxylic {gamma}-bromobutyrate-{sup 14}C is formed. This in turn gives {gamma}-amino-butyric carboxylic-{sup 14}C acid with an overall yield of 66 per cent with respect to Ba{sup 14}CO{sub 3}, when it is condensed with potassium phthalimide and hydrolyzed by acid. By reacting methyl-{gamma}-bromobutyrate-{sup 14}C with the sodium derivative of ethyl cyanacetamido-acetate in ethanol, followed by an acid hydrolysis, {alpha}-aminoadipic-6-{sup 14}C acid is obtained with an overall yield of 46 per cent with respect to Ba{sup 14}CO{sub 3}. (author) [French] La carbonatation du chlorure de {gamma}-methoxypropylmagnesium par {sup 14}CO{sub 2} donne l'acide {gamma}-methoxybutyrique carboxyle {sup 14}C avec un rendement d'environ 95 pour cent. Ce dernier traite successivement par HBr anhydre et par le diazomethane conduit au {gamma}-bromobutyrate de methyle carboxyle {sup 14}C. Celui-ci condense avec le phtalimide de potassium suivi d'une hydrolyse acide fournit l'acide {gamma}-aminobutyrique carboxyle {sup 14}C avec un rendement global de 66 pour cent par rapport a Ba{sup 14}CO{sub 3}. L'action du {gamma}-bromobutyrate de methyle {sup 14}C sur le derive sode du cyanacetamidoacetate d'ethyle dans l'ethanol suivie d'hydrolyse acide donne l'acide {alpha}-aminoadipique {sup 14}C-6 avec un rendement global de 46 pour cent par rapport a Ba{sup 14}CO{sub 3}. (auteur)

  5. Trifluoromethanesulfonic Anhydride as a Low-Cost and Versatile Trifluoromethylation Reagent.

    Science.gov (United States)

    Ouyang, Yao; Xu, Xiu-Hua; Qing, Feng-Ling

    2018-04-19

    A large number of reagents have been developed for the synthesis of trifluoromethylated compounds. However, an ongoing challenge in trifluoromethylation reaction is the use of less expensive and practical trifluoromethyl sources. We report herein the unprecedented direct trifluoromethylation of (hetero)arenes using trifluoromethanesulfonic anhydride as a radical trifluoromethylation reagent by merging photoredox catalysis and pyridine activation. Furthermore, introduction of both the CF 3 and OTf groups of the trifluoromethanesulfonic anhydride into internal alkynes to access tetrasubstituted trifluoromethylated alkenes was achieved. Since trifluoromethanesulfonic anhydride is a low-cost and abundant chemical, this method provides a cost-efficient and practical route to trifluoromethylated compounds. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Highly Carboxylated Cellulose Nanofibers via Succinic Anhydride Esterification of Wheat Fibers and Facile Mechanical Disintegration.

    Science.gov (United States)

    Sehaqui, H; Kulasinski, K; Pfenninger, N; Zimmermann, T; Tingaut, P

    2017-01-09

    We report herein the preparation of 4-6 nm wide carboxyl-functionalized cellulose nanofibers (CNF) via the esterification of wheat fibers with cyclic anhydrides (maleic, phtalic, and succinic) followed by an energy-efficient mechanical disintegration process. Remarkable results were achieved via succinic anhydride esterification that enabled CNF isolation by a single pass through the microfluidizer yielding a transparent and thick gel. These CNF carry the highest content of carboxyl groups ever reported for native cellulose nanofibers (3.8 mmol g -1 ). Compared to conventional carboxylated cellulose nanofibers prepared via Tempo-mediated oxidation of wheat fibers, the present esterified CNF display a higher molar-mass and a better thermal stability. Moreover, highly carboxylated CNF from succinic anhydride esterification were effectively integrated into paper filters for the removal of lead from aqueous solution and are potentially of interest as carrier of active molecules or as transparent films for packaging, biomedical or electronic applications.

  7. Evaluation of the effect of the acetic anhydride concentration, temperature and time in the acetylation reaction for chemical modification of Calophyllum brasiliense and Enterolobium cyclocarpum

    International Nuclear Information System (INIS)

    Blanco Arias, Ernesto

    2013-01-01

    A treatment is performed to increase the life of wood in Costa Rica. The effect of acetic anhydride concentration, temperature and time have been studied in the reaction of acetylation for the chemical modification of tropical species Calophyllum brasiliense (Cedar Maria) and Enterolobium cyclocarpum (Guanacaste). Species have been characterized for quantifying the amount of OH groups available for the acetylation reaction. An important aspect is that the temperature conditions, the ratio of acetic anhydride with has dry wood mass and initial acetic acid concentration were assessed using a factorial design and have determined the conditions with which has obtained greater weight gain in the acetylation reaction. Furthermore, the acetylation reaction was conducted for times of 2 hours, 4,5 hours and 7 hours. The ATR infrared spectroscopy was used to verify the replacement of the OH group by acetyl groups and the increase in the different reaction time. The characteristics obtained from the OH groups have been 13,23 mmol and 13,85 mmol of OH per gram of wood of the Guanacaste species and Cedar Maria respectively. The temperature has been 90 degrees Celsius, one relationship acetic anhydride/dry wood 1,75 mL/g without the initial presence of acetic acid in the reaction medium. Also, percentages of profit of weight (WPG) have been obtained; maximums of 12,20% and 12,44% for Guanacaste for Cedar Maria in reaction time of 7 hours, 4,5 hours respectively. A decrease in the band has performed in the 3300 cm -1 characteristic of the OH group and the presence of bands at 1700 cm -1 characteristic of C=O. One of the main conclusions is that the acetylated wood has been an increase in resistance to biological degradation by white rot fungus Trametes versicolor of about 87% efficiency for both species [es

  8. Electron beam curing of coatings

    International Nuclear Information System (INIS)

    Schmidt, J.; Mai, H.

    1986-01-01

    Modern low-energy electron beam processors offer the possibility for high-speed curing of coatings on paper, plastics, wood and metal. Today the electron beam curing gets more importance due to the increasing environmental problems and the rising cost of energy. For an effective curing process low-energy electron beam processors as well as very reactive binders are necessary. Generally such binders consist of acrylic-modified unsaturated polyester resins, polyacrylates, urethane acrylates or epoxy acrylates and vinyl monomers, mostly multifunctional acrylates. First results on the production of EBC binders on the base of polyester resins and vinyl monomers are presented. The aim of our investigations is to obtain binders with curing doses ≤ 50 kGy. In order to reduce the curing dose we studied mixtures of resins and acrylates. (author)

  9. CURING EFFICIENCY OF DUAL-CURE RESIN CEMENT UNDER ZIRCONIA WITH TWO DIFFERENT LIGHT CURING UNITS

    Directory of Open Access Journals (Sweden)

    Pınar GÜLTEKİN

    2015-04-01

    Full Text Available Purpose: Adequate polymerization is a crucial factor in obtaining optimal physical properties and a satisfying clinical performance from composite resin materials. The aim of this study was to evaluate the polymerization efficiency of dual-cure resin cement cured with two different light curing units under zirconia structures having differing thicknesses. Materials and Methods: 4 zirconia discs framework in 4 mm diameter and in 0.5 mm, 1 mm and 1.5 mm thickness were prepared using computer-aided design system. One of the 0.5 mm-thick substructures was left as mono-layered whereas others were layered with feldspathic porcelain of same thickness and ceramic samples with 4 different thicknesses (0.5, 1, 1.5 and 2.0 mm were prepared. For each group (n=12 resin cement was light cured in polytetrafluoroethylene molds using Light Emitting Diode (LED or Quartz-Tungsten Halogen (QHT light curing units under each of 4 zirconia based discs (n=96. The values of depth of cure (in mm and the Vickers Hardness Number values (VHN were evaluated for each specimen. Results: The use of LED curing unit produced a greater depth of cure compared to QTH under ceramic discs with 0.5 and 1 mm thickness (p<0.05.At 100μm and 300 μm depth, the LED unit produced significantly greater VHN values compared to the QTH unit (p<0.05. At 500 μm depth, the difference between the VHN values of LED and QTH groups were not statistically significant. Conclusion: Light curing may not result in adequate resin cement polymerization under thick zirconia structures. LED light sources should be preferred over QTH for curing dual-cure resin cements, especially for those under thicker zirconia restorations.

  10. Modification of cellulose with succinic anhydride in TBAA/DMSO mixed solvent under catalyst-free conditions

    Science.gov (United States)

    Homogeneous modification of cellulose with succinic anhydride was performed in tetrabutylammonium acetate (TBAA)/dimethyl sulfoxide (DMSO) mixed solvent. The molar ratio of succinic anhydride (SA) to free hydroxyl groups in the anhydroglucose units (AGU) and TBAA dosage were investigated as paramete...

  11. Modification of cellulose with succinic anhydride in TBAA/DMSO mixed solvent under catalyst-free conditions

    Science.gov (United States)

    Ping-Ping Xin; Yao-Bing Huang; Chung-Yun Hse; Huai N. Cheng; Chaobo Huang; Hui. Pan

    2017-01-01

    Homogeneous modification of cellulose with succinic anhydride was performed using tetrabutylammonium acetate (TBAA)/dimethyl sulfoxide (DMSO) mixed solvent. The molar ratio of succinic anhydride (SA) to free hydroxyl groups in the anhydroglucose units (AGU), TBAA dosage, reaction temperature, and reaction time were investigated. The highest degree of substitution (DS)...

  12. Strain development in a filled epoxy resin curing under constrained and unconstrained conditions as assessed by Fibre Bragg Grating sensors

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available The influence of adhesion to the mould wall on the released strain of a highly filled anhydride cured epoxy resin (EP, which was hardened in an aluminium mould under constrained and unconstrained condition, was investigated. The shrinkage-induced strain was measured by fibre optical sensing technique. Fibre Bragg Grating (FBG sensors were embedded into the curing EP placed in a cylindrical mould cavity. The cure-induced strain signals were detected in both, vertical and horizontal directions, during isothermal curing at 75 °C for 1000 minutes. A huge difference in the strain signal of both directions could be detected for the different adhesion conditions. Under non-adhering condition the horizontal and vertical strain-time traces were practically identical resulting in a compressive strain at the end of about 3200 ppm, which is a proof of free or isotropic shrinking. However, under constrained condition the horizontal shrinkage in the EP was prevented due to its adhesion to the mould wall. So, the curing material shrunk preferably in vertical direction. This resulted in much higher released compressive strain signals in vertical (10430 ppm than in horizontal (2230 ppm direction. The constrained cured EP resins are under inner stresses. Qualitative information on the residual stress state in the molding was deduced by exploiting the birefringence of the EP.

  13. Performance of maleated castor oil based plasticizer on rubber: rheology and curing characteristic studies

    Science.gov (United States)

    Indrajati, I. N.; Dewi, I. R.

    2017-07-01

    The objective of this study was to evaluate the performance of maleated castor oil (MACO) as plasticizer on natural rubber (NR), ethylene propylene diene monomer (EPDM), and nitrile butadiene rubber (NBR). The parameter studied were involving rheological, curing and swelling properties. The MACOs were prepared by an esterification reaction between castor oil (CO) and maleic anhydride (MAH) with the help of xylene as water entrainer to improve water removal. Resulting oils then applied as a plasticizer in each of those rubbers within a fixed loading of 5 phr. Comparison has been made to evaluate the performance of MACO and conventional plasticizer (paraffinic oil for NR and EPDM, DOP for NBR) on each rubber. Rheology, curing characteristic and swelling of each rubber were studied. The results showed that rubber (NR/EPDM/NBR) plasticized with MACO had given similar flow characteristic to conventional plasticizers. MACO exhibited slow curing, confirmed by higher t90, but the scorch safety was of the same magnitude. MAH loading tended to decrease the flow properties and curing rate, while scorch time (ts2) was independent.

  14. Cure of incurable lymphoma

    International Nuclear Information System (INIS)

    De Nardo, Gerald L.; Sysko, Vladimir V.; De Nardo, Sally J.

    2006-01-01

    The most potent method for augmenting the cytocidal power of monoclonal antibody (MAb) treatment is to conjugate radionuclides to the MAb to deliver systemic radiotherapy (radioimmunotherapy; RIT). The antigen, MAb, and its epitope can make a difference in the performance of the drug. Additionally, the radionuclide, radiochemistry, chelator for radiometals and the linker between the MAb and chelator can have a major influence on the performance of drugs (radiopharmaceuticals) for RIT. Smaller radionuclide carriers, such as antibody fragments and mimics, and those used for pretargeting strategies, have been described and evaluated. All of these changes in the drugs and strategies for RIT have documented potential for improved performance and patient outcomes. RIT is a promising new therapy that should be incorporated into the management of patients with B-cell non-Hodgkin's lymphoma (NHL) soon after these patients have proven incurable. Predictable improvements using better drugs, strategies, and combinations with other drugs seem certain to make RIT integral to the management of patients with NHL, and likely lead to cure of currently incurable NHL

  15. Accelerated dry curing of hams.

    Science.gov (United States)

    Marriott, N G; Kelly, R F; Shaffer, C K; Graham, P P; Boling, J W

    1985-01-01

    Uncured pork legs from the right side of 18 carcasses were treated with a Ross Tenderizer and the left side were controls. All 36 samples were dry-cured for 40, 56 or 70 days and evaluated for appearance traits, cure penetration characteristics, microbial load, Kramer Shear force and taste attributes. The tenderization treatment had no effect (P > 0·05) on visual color or cure penetration rate, weight loss before curing, percentage moisture, nitrate level, nitrite level, total plate count, anaerobic counts, psychrotrophic counts, objective and subjective tenderness measurements or juiciness. However, the higher values of salt suggested a possible acceleration of the dry cure penetration process among the tenderized samples. Cure time had no effect (P > 0·05) on percentage moisture, percentage salt, nitrate content, nitrite content, shear force and juiciness. Results suggest a limited effect of the mechanical tenderization process on certain traits related to dry curing and that total process time should be at least 70 days if color stability during cooking is desired. Copyright © 1985. Published by Elsevier Ltd.

  16. Relaxed Poisson cure rate models.

    Science.gov (United States)

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Electron curing of surface coatings

    International Nuclear Information System (INIS)

    Nablo, S.V.

    1974-01-01

    The technical development of electron curing of surface coatings has received great impetus since 1970 from dramatic changes in the economics of the conventional thermal process. The most important of these changes are reviewed, including: the Clear Air Act, increasing cost and restrictive allocation of energy, decreased availability and increased costs of solvents, competitive pressure for higher line productivity. The principles of free-radical initiated curing as they pertain to industrial coatings are reviewed. Although such electron initiated processes have been under active development for at least two decades, high volume production applications on an industrial scale have only recently appeared. These installations are surveyed with emphasis on the developments in machinery and coatings which have made this possible. The most significant economic advantages of electron curing are presented. In particular, the ability of electron curing to eliminate substrate damage and to eliminate the curing station (oven) as the pacing element for most industrial surface coating curing applications is discussed. Examples of several new processes of particular interest in the textile industry are reviewed, including the curing of transfer cast urethane films, flock adhesives, and graftable surface finishes

  18. Excimer UV curing in printing

    International Nuclear Information System (INIS)

    Mehnert, R.

    1999-01-01

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  19. The irradiation curing of coatings

    International Nuclear Information System (INIS)

    Autio, T.

    1974-01-01

    The electron beam irradiation curing of coatings has been technically feasible for over a decade. A brief description of the process is presented. The progress in this field has been astonishingly slow in comparison with the use of UV lamps as radiation source. The primary reason for this has been the great advantage in terms of capital cost of the UV curing lines and their ready adaptability to low or high production rates. A literature survey is given concerning basic and applied research in the electron curing area, patents, economics and existing installations around the world. (author)

  20. Radiation cured polyester compositions containing metal-properties

    Science.gov (United States)

    Szalińska, H.; Pietrzak, M.; Gonerski, A.

    The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

  1. Radiation cured polyester compositions containing metal-properties

    International Nuclear Information System (INIS)

    Szalinska, H.; Pietrzak, M.; Gonerski, A.

    1987-01-01

    The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60 Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them. (author)

  2. A new approach to quantification of DTPA incorporation into monoclonal antibodies (MoAbs) labeled by the cyclic anhydride DTPA method

    International Nuclear Information System (INIS)

    Wang, T.S.T.; Ng, A.K.; Fawwaz, R.A.; Alsedairy, S.; Alderson, P.O.

    1985-01-01

    A method for determining the ratio of DTPA molecules attached per molecule of Ab was developed and used to examine the immunoreactivity of different Abs as a function of the amount of incorporated DTPA. The bicyclic anhydride of DTPA[2-C-14]acetic acid (BADTPA-C-14) was synthesized by reacting DTPA[2-C-14]acetic acid (1mCi/mmo1) and acetic anhydride. BADTPA-C-14 then was reacted with a MoAb to a melanoma associated antigen (MA) and to a MoAb to human HLA class II antigen (HLA) at 2mg/m1 of MoAb concentration, at MoAb to BADTPA-C-14 ratios (mmo1/mmo1) of l:1, 1:10, 1:00, l:200. The conjugate was dialyzed exhaustively against HEPES at pH 7.0. The MoAb concentration was measured at 280mm of uv; the DTPA/MoAb ratio was calculated based on the specific activity of BADTPA-C-14, and the immunoreactivity was assessed by direct cell-binding to melanoma, the HLA antigen and control (lymphoma) cells. Percent binding to the lymphoid cell line was less than 3%. The authors' results demonstrated a method for directly determining the number of DTPA molecules attached to a MOAb, and demonstrated variations in immunoreactivity as the number of DTPA groups per MoAb is altered

  3. Self-curing concrete with different self-curing agents

    Science.gov (United States)

    Gopala krishna sastry, K. V. S.; manoj kumar, Putturu

    2018-03-01

    Concrete is recognised as a versatile construction material globally. Properties of concrete depend upon, to a greater extent, the hydration of cement and microstructure of hydrated cement. Congenial atmosphere would aid the hydration of cement and hence curing of concrete becomes essential, till a major portion of the hydration process is completed. But in areas of water inadequacy and concreting works at considerable heights, curing is problematic. Self-Curing or Internal Curing technique overcomes these problems. It supplies redundant moisture, for more than sufficient hydration of cement and diminish self-desiccation. Self-Curing agents substantially help in the conservation of water in concrete, by bringing down the evaporation during the hydration of Concrete. The present study focuses on the impact of self-curing agents such as Poly Ethylene Glycol (PEG), Poly Vinyl Alcohol (PVA) and Super Absorbent Polymer (SAP) on the concrete mix of M25 grade (reference mix). The effect of these agents on strength properties of Concrete such as compressive strength, split tensile strength and flexural strength was observed on a comparative basis which revealed that PEG 4000 was the most effective among all the agents.

  4. Respiratory Allergy to Trimellitic Anhydride in Rats: Concentration-Response Relationships during Elicitation

    NARCIS (Netherlands)

    Arts, J.H.E.; Koning, M.W. de; Bloksma, N.; Kuper, C.F.

    2004-01-01

    The present study investigated whether airway responses of sensitized rats to trimellitic anhydride (TMA) were concentration dependent and whether these were related to irritation by TMA. Groups of BN and Wistar rats were sensitized by two dermal applications of TMA (50% w/v, followed by 25% w/v in

  5. Blends of Styrene-Butadiene-Styrene Triblock Copolymer with Random Styrene-Maleic Anhydride Copolymers

    NARCIS (Netherlands)

    Piccini, Maria Teresa; Ruggeri, Giacomo; Passaglia, Elisa; Picchioni, Francesco; Aglietto, Mauro

    2002-01-01

    Blends of styrene-butadiene-styrene triblock copolymer (SBS) with random styrene-maleic anhydride copolymers (PS-co-MA), having different MA content, were prepared in a Brabender Plastigraph mixer. The presence of polystyrene (PS) blocks in the SBS copolymer and the high styrene content (93 and 86

  6. Formation and stability of Vitamin E enriched nanoemulsions stabilized by Octenyl Succinic Anhydride modified starch

    Science.gov (United States)

    Vitamin E (VE) is highly susceptible to autoxidation; therefore, it requires systems to encapsulate and protect it from autoxidation.In this study,we developed VE delivery systems, which were stabilized by Capsul® (MS), a starch modified with octenyl succinic anhydride. Influences of interfacial ten...

  7. Maleic anhydride based copolymer dispersions for surface modification of polar substrates

    NARCIS (Netherlands)

    Gunbas, I.D.; Wouters, M.E.L.; Hendrix, M.M.R.M.; Benthem, R.A.T.M. van; Koning, C.E.; Noordover, B.A.J.

    2012-01-01

    In this article, we report the modification of poly(styrene-alt-maleic anhydride) (PSMA) with monofunctional amine-terminated poly(dimethyl siloxane) (PDMS-NH2) by thermal imidization, followed by the preparation and characterization of a surfactant-free artificial latex thereof and application of

  8. Maleic anhydride based copolymer dispersions for surface modification of polar substrates

    NARCIS (Netherlands)

    Gunbas, I.D.; Wouters, M.E.L.; Hendrix, M.M.R.M.; Benthem, van R.A.T.M.; Koning, C.E.; Noordover, B.A.J.

    2012-01-01

    In this article, we report the modification of poly(styrene-alt-maleic anhydride) (PSMA) with monofunctional amine-terminated poly(dimethyl siloxane) (PDMS–NH2) by thermal imidization, followed by the preparation and characterization of a surfactant-free artificial latex thereof and application of

  9. Synthesized cellulose/succinic anhydride as an ion exchanger. Calorimetry of divalent cations in aqueous suspension

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Julio C.P. [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP (Brazil); Silva Filho, Edson C. [LIMAV, Federal University of Piaui, 64049-550 Teresina, Piaui (Brazil); Santana, Sirlane A.A. [Departamento de Quimica/CCET, Universidade Federal do Maranhao, Av. dos Portugueses S/N, Campus do Bacanga, 65080-540 Sao Luiz, MA (Brazil); Airoldi, Claudio, E-mail: airoldi@iqm.unicamp.br [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP (Brazil)

    2011-09-20

    Highlights: {yields} Synthetic route based on anhydride melting point. {yields} Cellulosic biopolymer/anhydride as ion exchanger. {yields} Calorimetry of cation exchange at solid/liquid interface. {yields} Favorable thermodynamic data of exchanging process. - Abstract: A synthetic route to a biopolymer/anhydride ion exchanger adds cellulose directly to molten succinic anhydride in a quasi solvent-free procedure. An amount of 3.07 {+-} 0.05 mmol of pendant groups incorporated onto the polymeric structure, which was characterized by elemental analysis, solid state carbon NMR, infrared, X-ray and thermogravimetry. The new polysaccharide is able to exchange cations from aqueous solution through a batchwise methodology, to obtain 2.46 {+-} 0.09 mmol g{sup -1} for divalent cobalt and nickel cations. The net thermal effects obtained from calorimetric titrations gave endothermic values of 3.81 {+-} 0.02 and 2.35 {+-} 0.01 kJ mol{sup -1}. The spontaneity of this ion-exchange process reflected in negative Gibbs energies and also a positive entropic contribution. These thermodynamic data at the solid/liquid interface suggests a favorable ion exchange process for this anchored biopolymer, for cation removal from the environment.

  10. Controlled release from aspirin based linear biodegradable poly(anhydride esters) for anti-inflammatory activity.

    Science.gov (United States)

    Dasgupta, Queeny; Movva, Sahitya; Chatterjee, Kaushik; Madras, Giridhar

    2017-08-07

    This work reports the synthesis of a novel, aspirin-loaded, linear poly (anhydride ester) and provides mechanistic insights into the release of aspirin from this polymer for anti-inflammatory activity. As compared to conventional drug delivery systems that rely on diffusion based release, incorporation of bioactives in the polymer backbone is challenging and high loading is difficult to achieve. In the present study, we exploit the pentafunctional sugar alcohol (xylitol) to provide sites for drug (aspirin) attachment at its non-terminal OH groups. The terminal OH groups are polymerized with a diacid anhydride. The hydrolysis of the anhydride and ester bonds under physiological conditions release aspirin from the matrix. The resulting poly(anhydride ester) has high drug loading (53%) and displays controlled release kinetics of aspirin. The polymer releases 8.5 % and 20%, of the loaded drug in one and four weeks, respectively and has a release rate constant of 0.0035h -0.61 . The release rate is suitable for its use as an anti-inflammatory agent without being cytotoxic. The polymer exhibits good cytocompatibility and anti-inflammatory properties and may find applications as injectable or as an implantable bioactive material. The physical insights into the release mechanism can provide development of other drug loaded polymers. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. THE GRAFTING OF MALEIC-ANHYDRIDE ON HIGH-DENSITY POLYETHYLENE IN AN EXTRUDER

    NARCIS (Netherlands)

    GANZEVELD, KJ; JANSSEN, LPBM

    The grafting of maleic anhydride (MAH) on high density polyethylene in a counter-rotating twin screw extruder has been studied. As the reaction kinetics appear to be affected by mass transfer, good micro mixing in the extruder is important. Due to the competing mechanisms of increasing mixing and

  12. Catalytic ring-​opening copolymerization of limonene oxide and phthalic anhydride : toward partially renewable polyesters

    NARCIS (Netherlands)

    Hosseini Nejad, E.; Pionasari, A; Melis, van C.G.W.; Koning, C.E.; Duchateau, R.

    2013-01-01

    Catalytic ring-¿opening copolymn. of limonene oxide with phthalic anhydride was performed applying metal t-¿Bu-¿salophen complexes (t-¿Bu-¿salophen)¿MX; M = Cr, X = Cl (1)¿, M = Al, X = Cl (2)¿, M = Co, X = OAc (3)¿, M = Mn, X = Cl (4)¿, t-¿Bu-¿salophen =

  13. Towards anti-corrosion coatings from surfactant-free latexes based on maleic anhydride containing polymers

    NARCIS (Netherlands)

    Soer, W.J.; Ming, W.; Koning, C.E.; Benthem, van R.A.T.M.

    2008-01-01

    We report on the film formation of surfactant-free, artificial latexes based on copolymers containing maleic anhydride. Different metallic substrates, such as aluminum, steel and magnesium alloys, were coated with three different latexes. A commercial polyester based coating was used as a

  14. Modified Julia Olefination on Anhydrides: Extension and Limitations. Application to the Synthesis of Maculalactone B.

    Science.gov (United States)

    Dussart, Nicolas; Trinh, Huu Vinh; Gueyrard, David

    2016-10-07

    The preparation of exo-enol esters from cyclic anhydrides is reported using a modified Julia olefination. The reaction is highly stereoselective. The Smiles rearrangement can be performed in a one-pot process, giving a straightforward access to exo-enol lactones. Furthermore, the reaction was extended to semistabilized sulfones, and this methodology was applied to the synthesis of maculalactone B.

  15. Industrial application of radiation curing

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Takashi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1994-12-31

    The contents are advantages of radiation processes - a solvent-free system, less energy consumative, higher production rate, processability at ambient temperature; electron beams vs. ultraviolet curing; applications -broad spectrum of markets use radiation curable materials.

  16. Novel techniques for concrete curing

    DEFF Research Database (Denmark)

    Kovler, Konstantin; Jensen, Ole Mejlhede

    2005-01-01

    It is known that some high-strength/high-performance concretes (HSC/HPC) are prone to cracking at an early age unless special precautions are taken. The paper deals with the methods of curing as one of the main strategies to ensure good performance of concrete. Curing by both external (conventional......) and internal methods is reviewed and analyzed, among other methods of mitigating shrinkage and cracking of concrete. The focus is on the mitigation of autogenous shrinkage of low water to binder ratio (w/b) concrete by means of internal curing. The concepts of internal curing are based on using lightweight...... aggregate, superabsorbent polymers or water-soluble chemicals, which reduce water evaporation (so called "internal sealing"). These concepts have been intensively researched in the 90s, but still are not widespread among contractors and concrete suppliers. The differences between conventional methods...

  17. Radiation curing of polymers II

    International Nuclear Information System (INIS)

    Randell, D.R.

    1991-01-01

    During the last decade radiation cured polymers have continued to grow in importance not only by expansion within existing coatings applications but also by extension into new fields of application such as ceramics, ink-jet inks and fibres. To provide a further update on the rapidly growing science and technology of radiation curing the Third International Symposium was held. Apart from providing an update on the application, chemistry and control aspects of the radiation curing the aim of the meeting was also to provide the newcomer with a basic insight into radiation curing applications. Accordingly the proceedings contained in this special publication which follow closely the format of the meeting, has five sections covering the background/trends, applications, initiator chemistry, substrate chemistry and analytical, physical chemical and health and safety aspects. There are twenty-five papers all told, three of which are indexed separately. (Author)

  18. Industrial application of radiation curing

    International Nuclear Information System (INIS)

    Takashi Sasaki

    1993-01-01

    The contents are advantages of radiation processes - a solvent-free system, less energy consumative, higher production rate, processability at ambient temperature; electron beams vs. ultraviolet curing; applications -broad spectrum of markets use radiation curable materials

  19. Monitoring Prepregs As They Cure

    Science.gov (United States)

    Young, P. R.; Gleason, J. R.; Chang, A. C.

    1986-01-01

    Quality IR spectra obtained in dynamic heating environment. New technique obtains quality infrared spectra on graphite-fiber-reinforced, polymeric-matrix-resin prepregs as they cure. Technique resulted from modification of diffuse reflectance/Fourier transform infrared (DR/FTIR) technique previously used to analyze environmentally exposed cured graphite composites. Technique contribute to better understanding of prepreg chemistry/temperature relationships and development of more efficient processing cycles for advanced materials.

  20. Triflic Anhydride-Mediated Beckmann Rearrangement Reaction of β ...

    Indian Academy of Sciences (India)

    aSchool of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China. bKey Laboratory of Synthetic Rubber, Changchun Institute of Applied Chemistry, ... which meanwhile releases quite a lot of acidic wastes.1,3.

  1. Modified Method for Detection of Benzoylecgonine in Human Urine by GC-MS: Derivatization Using Pentafluoropropanol/Acetic Anhydride.

    Science.gov (United States)

    Serafin, Michelle C; Paulemon, Kasandra M; Fuller, Zachary J; Bronner, William E

    2017-05-01

    An existing GC-MS method for detecting benzoylecgonine (BZE) in urine was modified by changing derivatizing reagents. This method modification presents a cost-effective alternative derivatization procedure for the detection of BZE in urine by GC-MS. The combination of pentafluoropropanol and acetic anhydride was found to produce the same reaction product for BZE as pentafluoropropanol with pentafluoropropionic anhydride, while reducing reagent cost. With no anhydride present, derivatization of BZE by pentafluoropropanol did not occur. Published by Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  2. Cure Schedule for Stycast 2651/Catalyst 11.

    Energy Technology Data Exchange (ETDEWEB)

    Kropka, Jamie Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); McCoy, John D. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2017-11-01

    The Henkel technical data sheet (TDS) for Stycast 2651/Catalyst 11 lists three alternate cure schedules for the material, each of which would result in a different state of reaction and different material properties. Here, a cure schedule that attains full reaction of the material is defined. The use of this cure schedule will eliminate variance in material properties due to changes in the cure state of the material, and the cure schedule will serve as the method to make material prior to characterizing properties. The following recommendation was motivated by (1) a desire to cure at a single temperature for ease of manufacture and (2) a desire to keep the cure temperature low (to minimize residual stress build-up associated with the cooldown from the cure temperature to room temperature) without excessively limiting the cure reaction due to vitrification (i.e., material glass transition temperature, Tg, exceeding cure temperature).

  3. Color and oxidative stability of nitrite-free cured meat after gamma irradiation

    International Nuclear Information System (INIS)

    Shahidi, F.; Pegg, R.B.; Shamsuzzaman, K.

    1991-01-01

    The effects of 5 and 10 kGy irradiation on the color and oxidative stability of meats treated with nitrite or a nitrite-free curing system were investigated. The nitrite-free curing system consisted of the preformed cooked cured-meat pigment, sodium ascorbate and sodium tripolyphosphate with or without sodium acid pyrophosphate. Irradiation had no detrimental effects on the color or flavor of either cured samples. Polyphosphates had a beneficial effect on oxidative stability but had a slight detrimental effect on color stability of irradiated samples

  4. Mixture proportioning for internal curing

    DEFF Research Database (Denmark)

    Bentz, Dale P.; Pietro, Lura; Roberts, John W.

    2005-01-01

    of additional internal water that is not part of the mixing water.” The additional internal water is typically supplied by using relatively small amounts of saturated, lightweight, fine aggregates (LWA) or superabsorbent polymer (SAP) particles in the concrete. Benefits of internal curing include increased...... less than that of bulk water, a hydrating cement paste will imbibe water (about 0.07 g water/g cement) from an available source. While in higher w/c concretes, this water can be, and often is, supplied by external (surface) curing, in low w/c concretes, the permeability of the concrete quickly becomes...

  5. Preparation and Mechanical Properties of Chitosan-graft Maleic Anhydride Reinforced with Montmorillonite

    Science.gov (United States)

    Fajrin, A.; Sari, L. A.; Rahmawati, N.; Saputra, O. A.; Suryanti, V.

    2017-02-01

    The research aims to develop biodegradable composites as bio-based plastics from chitosan. The composites were prepared via solution casting method by introducing the maleic anhydride (MAH) as grafting agent and montmorillonite (MMt) as reinforcement. The grafting process of chitosan was conducted by varying concentrations of MAH which were 10, 20, and 30% w/w. It was observed that the chitosan-graft-maleic anhydride (Cs-g-MAH) containing 10% w/w of MAH increased its tensile strength by 70%. Reinforcement material was added to the Cs-g-MAH by varying MMt concentrations, e.g. 3, 6, 9 and 12% w/w. It was noted that the presence of 9% w/w of MMt in the Cs-g-MAH gave the best mechanical properties of the Cs-g-MAH/MMt composite.

  6. Synthesis and characterization of Cis-5-Norbornene-2, 3-dicarboxylic anhydride-chitosan

    International Nuclear Information System (INIS)

    Ku Marshilla Ku Ishak; Zulkifli Ahmad; Hazizan Mohd Akil

    2009-01-01

    Chitosan was chemically modified with bulky structure, cis-5-norbornene-2, 3-dicarboxylic anhydride and the characteristic of this modified chitosan was studied. The resulting material was analyzed by FTIR, TGA, DSC, XRD and SEM to study the effect of N-acylation to the polysaccharide structure. FTIR results show that the anhydride monomer was successfully bound to amine group of chitosan. Thermal analysis of the modified structure provides the chitosan fibers with thermal stability while XRD and SEM show the lost of crystallinity of modified chitosan. XRD of modified chitosan shows broader peak pattern and a considerable increase in a dimension while SEM of chitosan presented the single particle morphology while norbornene-chitosan shows aggromolarate behaviour due to the hydrophobic nature of norbornene pendant group which induced aggromolaration of the particles in modified structure.(author)

  7. Biomaterial properties evaluation of poly(vinyl acetate- alt-maleic anhydride)/chitosan nanocapsules

    Science.gov (United States)

    Raţă, Delia Mihaela; Popa, Marcel; Chailan, Jean-François; Zamfir, Carmen Lăcrămioara; Peptu, Cătălina Anişoara

    2014-08-01

    Nanocapsules with diameter around 100 nm based on a natural polymer (chitosan) and a synthetic polymer poly(vinyl acetate- alt-maleic anhydride) [poly(MAVA)] by interfacial condensation method were prepared. The present study proposes a new type of biocompatible nanocapsules based on poly(vinyl acetate- alt-maleic anhydride-chitosan) (MCS) able to become a reliable support for inclusion and release of drugs. The spherical shape of the nanocapsules was evidenced by scanning electron microscopy. Nanocapsules presented a good Norfloxacin loading and release capacity. Haemocompatibility tests have demonstrated that the nanocapsules present a low toxicity and a good compatibility with sanguine medium. The biocompatibility properties of the nanocapsules after their intraperitoneal administration in rats were evidenced by histopathological examination of different organs (brain, liver, kidney, and lung). The results are encouraging and the nanocapsules can be used as controlled drug delivery systems.

  8. Application of the photo-fenton process to the mineralization of phthalic anhydride in aqueous medium

    International Nuclear Information System (INIS)

    Trabelsi Souissi, Souhaila; Oturan, N.; Oturan, M. A; Bellakhal, N.

    2009-01-01

    A photochemical method for the oxidation of persistent organic pollutants (POPs) present in liquid effluents of plastic industry is described. This method, called p hoto-Fenton , involves the generation of hydroxyl radicals by coupling the Fenton reaction and photochemistry, .OH radicals thus formed react rapidly with organic pollutants leading to their oxidation until their total mineralization. In this study, we applied the photo-Fenton process for the removal of phthalic anhydride (plasticizer). In this way, an optimization of experimental parameters (namely the ratio R = [H 2 O 2 ]/[Fe 3+ ] and Fe 3+ initial concentration) was performed. Under optimal conditions, the kinetic of mineralization of phthalic anhydride by .OH has been studied. All results confirm the efficiency of photo-Fenton process for the decontamination of liquid effluents loaded with plasticizers.

  9. Perylene anhydride fused porphyrins as near-infrared sensitizers for dye-sensitized solar cells

    KAUST Repository

    Jiao, Chongjun

    2011-07-15

    Two perylene anhydride fused porphyrins 1 and 2 have been synthesized and employed successfully in dye-sensitized solar cells (DSCs). Both compounds showed broad incident monochromatic photon-to-current conversion efficiency spectra covering the entire visible spectral region and even extending into the near-infrared (NIR) region up to 1000 nm, which is impressive for ruthenium-free dyes in DSCs. © 2011 American Chemical Society.

  10. Novel Synthesis of Phytosterol Ester from Soybean Sterol and Acetic Anhydride.

    Science.gov (United States)

    Yang, Fuming; Oyeyinka, Samson A; Ma, Ying

    2016-07-01

    Phytosterols are important bioactive compounds which have several health benefits including reduction of serum cholesterol and preventing cardiovascular diseases. The most widely used method in the synthesis of its ester analogous form is the use of catalysts and solvents. These methods have been found to present some safety and health concern. In this paper, an alternative method of synthesizing phytosterol ester from soybean sterol and acetic anhydride was investigated. Process parameters such as mole ratio, temperature and time were optimized. The structure and physicochemical properties of phytosterol acetic ester were analyzed. By the use of gas chromatography, the mole ratio of soybean sterol and acetic anhydride needed for optimum esterification rate of 99.4% was 1:1 at 135 °C for 1.5 h. FTIR spectra confirmed the formation of phytosterol ester with strong absorption peaks at 1732 and 1250 cm(-1) , which corresponds to the stretching vibration of C=O and C-O-C, respectively. These peaks could be attributed to the formation of ester links which resulted from the reaction between the hydroxyl group of soybean sterol and the carbonyl group of acetic anhydride. This paper provides a better alternative to the synthesis of phytosterol ester without catalyst and solvent residues, which may have potential application in the food, health-care food, and pharmaceutical industries. © 2016 Institute of Food Technologists®

  11. Radiation grafting of styrene and maleic anhydride onto PTFE membranes and sequent sulfonation for applications of vanadium redox battery

    International Nuclear Information System (INIS)

    Qiu Jingyi; Ni Jiangfeng; Zhai Maolin; Peng Jing; Zhou Henghui; Li Jiuqiang; Wei Genshuan

    2007-01-01

    Using γ-radiation technique, poly(tetrafluoroethylene) (PTFE) membrane was grafted with styrene (St) (PTFE-graft-PS) or binary monomers of St and maleic anhydride (MAn) (PTFE-graft-PS-co-PMAn), respectively. Then grafted membranes were further sulfonated with chlorosulfonic acid into ion-exchange membranes (denoted as PTFE-graft-PSSA and PTFE-graft-PSSA-co-PMAc, respectively) for application of vanadium redox battery (VRB). Micro-FTIR analysis indicated that PTFE was successfully grafted and sulfonated at the above two different conditions. However, a higher degree of grafting (DOG) was obtained in St/MAn binary system at the same dose due to a synergistic effect. Comparing with PTFE-graft-PSSA, PTFE-graft-PSSA-co-PMAc membrane showed higher water uptake and ion-exchange capacity (IEC) and lower area resistance (AR) at the same DOG. In addition, PTFE-graft-PSSA-co-PMAc with 6% DOG also showed a higher IEC and higher conductivity compared to Nafion membrane. Radiation grafting of PTFE in St/MAn binary system and sequent sulfonation is an appropriate method for preparing ion-exchange membrane of VRB

  12. Extraction of Micro- and Nano-Fibrils from Nylon 6/Polypropylene Grafted with Maleic Anhydride/Polypropylene Blended Films

    Directory of Open Access Journals (Sweden)

    E. Bagheban Kochak

    2013-01-01

    Full Text Available Atechnical feasibility study has been conducted on production of nano- and micro-fibrils from nylon 6/polypropylene grafted with maleic anhydride/polypropylene blended films. Fibrils are prepared in four consecutive steps.In the first step the polymers melt blended in an extruder with and without compatibilizers to produce chips; in the second step films are extruded from polymer blends chips, in the third step films are cold drawn with different draw ratios at room temperature and in the forth step fibrils are extracted by Soxhlet extraction with formic acid as solvent for nylon 6.  The films and fibrils were examined by scanning electron microscope and FTIR spectroscopy. It is found that the polypropylene dispersed phase deforms and coalesces into elongated fibrils during drawing  operation. The  fibrils’ diameters in the blends containing compatibilizer are more uniform and are smaller than those from films without compatibilizers. The thinnest polypropylene fibril observed has a diameter around 300 nm with the aspect ratio above 150. The stress-elongation curves show three distinctive regions, elastic, yield and hardening-leading to breakage. The elastic region is short and follows by necking and yield, i.e., elongation without increase in load. The hardening region is accompanied by the increase in the slope. The deformations of the polypropylene particles are noticed during the last regions of the extension; the fibril deformations seem to be more severe during breakage.

  13. Controlled sulfonation of poly(ether sulfone using phthalic anhydride as catalyst and its membrane performance for fuel cell application

    Directory of Open Access Journals (Sweden)

    Seikh Jiyaur Rahaman

    2016-09-01

    Full Text Available Proton exchange membrane (PEM fuel cells are one of the most emerging alternative energy technologies under development. A novel proton exchange membrane sulfonated polyethersulfone (SPES was developed by homogeneous method using phthalic anhydride as catalyst and chlorosulfonic acid as sulfonating agent to control the sulfonation reaction. The method of sulfonation was optimized by varying the reaction time and concentration of the catalyst. The structure of the SPES was studied by 1H-Nuclear Magnetic Resonance, Fourier Transform Infra Red Spectroscopy and X-ray diffraction. The extent of sulfonation was determined by ion exchange capacity studies. The thermal and mechanical stabilities were studied using thermogravimetric analysis (TGA and Dynamic Mechanical Analysis (DMA respectively. DMA results show that the storage modulus increased with increase in degree of sulfonation (DS and water uptake of SPES increased with DS. The proton conductivity of SPES (34% DS measured by impedance spectroscopy was found to be 0.03S/cm at 80%RH and 100°C. Also, current-voltage polarization characteristics of SPES membranes offer a favourable alternative PEM due to the thermal stability and cost effective than perfluorinated ionomers.

  14. Carbon Nanotubes Reinforced Maleic Anhydride-Modified Xylan-g-Poly(N-isopropylacrylamide) Hydrogel with Multifunctional Properties

    Science.gov (United States)

    Liu, Xinxin; Song, Tao; Chang, Minmin; Meng, Ling; Wang, Xiaohui; Sun, Runcang; Ren, Junli

    2018-01-01

    Introducing multifunctional groups and inorganic material imparts xylan-based hydrogels with excellent properties, such as responsiveness to pH, temperature, light, and external magnetic field. In this work, a composite hydrogel was synthesized by introducing acid treated carbon nanotubes (AT-CNTs) into the maleic anhydride modified xylan grafted with poly(N-isopropylacrylamide) (MAX-g-PNIPAM) hydrogels network. It was found that the addition of AT-CNTs affected the MAX-g-PNIPAM hydrogel structure, the swelling ratio and mechanical properties, and imparted the hydrogel with new properties of electrical conductivity and near infrared region (NIR) photothermal conversion. AT-CNTs could reinforce the mechanical properties of MAX-g-PNIPAM hydrogels, being up to 83 kPa for the compressive strength when the amount was 11 wt %, which was eight times than that of PNIPAM hydrogel and four times than that of MAX-g-PNIPAM hydrogel. The electroconductibility was enhanced by the increase of AT-CNTs amounts. Meanwhile, the composite hydrogel also exhibited multiple shape memory and NIR photothermal conversion properties, and water temperature was increased from 26 °C to 56 °C within 8 min under the NIR irradiation. Thus, the AT-CNTs reinforced MAX-g-PNIPAM hydrogel possessed promising multifunctional properties, which offered many potential applications in the fields of biosensors, thermal-arrest technology, and drug-controlled release. PMID:29495611

  15. Electron beam curing of coating

    International Nuclear Information System (INIS)

    Fujioka, S.; Fujikawa, Z.

    1974-01-01

    Electron beam curing (EBC) method, by which hardened coating film is obtained by polymerizing and cross-linking paint with electron beam, has finally reached industrialized stage. While about seven items such as short curing time, high efficiency of energy consumption, and homogeneous curing are enumerated as the advantages of EBC method, it has limitations of the isolation requirement from air needing the injection of inert gas, and considerable amount of initial investment. In the electron accelerators employed in EBC method, the accelerating voltage is 250 to 750 kV, and the tube current is several tens of mA to 200 mA. As an example of EBC applications, EBC ''Erio'' steel sheet was developed by the cooperative research of Nippon Steel Corp., Dai-Nippon Printing Co. and Toray Industries, Inc. It is a high-class pre-coated metal product made from galvanized steel sheets, and the flat sheets with cured coating are sold, and final products are fabricated by being worked in various shapes in users. It seems necessary to develop the paint which enables to raise added value by adopting the EBC method. (Wakatsuki, Y.)

  16. Expert incentives: cure versus prevention

    NARCIS (Netherlands)

    de Jaegher, K.

    This paper distinguishes between two scenarios for the expert-client encounter. In the cure scenario, the client does not know whether a loss can be recovered. In the prevention scenario, the client faces a threat but does not know whether this threat is real enough to justify preventive action. The

  17. Advances in spot curing technology

    International Nuclear Information System (INIS)

    Burga, R.

    1999-01-01

    A brief review of spot curing technology was presented. The process which a spot of energy of a specific wavelength bandwidth and irradiance is used to cause a coating, encapsulant or adhesive to change from a liquid to a solid state

  18. Cure shrinkage in casting resins

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J. Brock [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    A method is described whereby the shrinkage of a casting resin can be determined. Values for the shrinkage of several resin systems in frequent use by Sandia have been measured. A discussion of possible methods for determining the stresses generated by cure shrinkage and thermal contraction is also included.

  19. Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements.

    Science.gov (United States)

    Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

    2014-04-01

    The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high

  20. Additives in UV and ionising radiation grafting and curing processes

    International Nuclear Information System (INIS)

    Garnett, J.L.; Ng, L.T.; Viengkhou, V.

    1998-01-01

    Full text: Curing of polymers induced by both UV and ionising radiation are now established technologies. Currently both systems are predominantly based on acrylate chemistry. UV processes use photoinitiators to achieve fast polymerisation. In the proposed paper the significance of the occurrence of concurrent grafting with cure will be examined. particularly with respect to the recycling of finished product. Basic studies on grafting initiated by UV and ionising radiation will be discussed. Polar methyl methacrylate (MMA) and non-polar styrene will be used as representative monomers with cellulose and propylene typifying the backbone polymers. The additives chosen for examination in this study are predominantly components used in radiation curing formulations since grafting and curing are known to be mechanically related. The additives used were mineral acid, photoinitiators, vinyl ethers, oligomers, polyfunctional monomers including multifunctional acrylates (MFAs) and methacrylates (MFMAs). For the first time the use of charge transfer complexes in the Mulliken sense as additives in radiation grafting will be discussed. The CT complexes themselves, being monomers, have also been grafted to the above polymers. Recent developments with excimer laser sources for initiating these processes will be discussed, especially the use of non-acrylate chemistry. Excimer laser sources are shown to complement conventional UV and ionising radiation and are photoinitiator free. Mechanisms for the above grafting and curing processes will be outlined

  1. Thermal curing of PBI membranes for high temperature PEM fuel cells

    DEFF Research Database (Denmark)

    Aili, David; Cleemann, Lars N.; Li, Qingfeng

    2012-01-01

    (MEAs) is currently hampering the commercial viability of the technology. In the present study, thermoset PBI membranes were prepared by curing the membranes under inert atmosphere at temperatures of up to 350 °C prior to the acid doping. The systematic membrane characterizations with respect...... to solubility, phosphoric acid doping, radical-oxidative resistance and mechanical strength indicated that the PBI membranes were irreversibly cured by the thermal treatment. After curing, the PBI membranes demonstrated features that are fundamental characteristics of a thermoset resin including complete...

  2. Radiation sources EB and UV curing machines

    International Nuclear Information System (INIS)

    Takashi Sasaki

    1993-01-01

    This paper describes electron beam processors and related technologies for curing applications to facilitate those industrial personals who are trying to understand and evaluate the applicability and benefits of radiation curing to their products. 4 tabs., 10 figs

  3. Radiation sources EB and UV curing machines

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Takashi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1994-12-31

    This paper describes electron beam processors and related technologies for curing applications to facilitate those industrial personals who are trying to understand and evaluate the applicability and benefits of radiation curing to their products. 4 tabs., 10 figs.

  4. Development situation of radiation curing materials

    International Nuclear Information System (INIS)

    He Songhua; Luo Junyi; Liu Zhen

    2010-01-01

    Due to fitting the '4E' principle, radiation curing technology, known as green technology, have shown its own superiority in many applications. It has been rapid developed in China and abroad in recent years, especially ultraviolet/electron beam (UV/EB) radiation curing technology. In order to let the researchers have a general understanding on the radiation curing materials and their development, in this paper a briefly introducing on the related radiation sources, chemical systems, curing mechanism, and the application, the common and difference of ultraviolet curing and electron beam curing has been made. A brief account of development of radiation-curable material in China and the outlook of the development of materials can be found in this paper. At last, we have proposed that the development of radiation curing technology will promote the development of the radiation curing material and benefit in the humanity. (authors)

  5. Techniques for internal water curing of concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Pietro, Lura

    2003-01-01

    This paper gives an overview of different techniques for incorporation of internal curing water in concrete. Internal curing can be used to mitigate self-desiccation and self-desiccation shrinkage. Some concretes may need 50 kg/m3 of internal curing water for this purpose. The price of the internal...

  6. Radiation curing: Science and technology

    International Nuclear Information System (INIS)

    Pappas, S.P.

    1992-01-01

    The science and technology of radiation curing have progressed substantially within the last 20 years. Nevertheless, radiation-curable compositions typically command relatively small shares in many of their competitive markets. This situation signifies that potential advantages of radiation curing are not generally perceived to overcome their limitations. An important objective of this book is to address this issue, within the scope of the subjects offered, by providing the present state of knowledge and by identifying the directions and challenges for future studies. The first chapter introduces radiation curing. Chapter 2 offers the first systematic presentation of inorganic and organometallic photoinitiators. Chapters 3 and 4 present the analytical techniques of photocalorimetry and real-time infrared spectroscopy, respectively. Recent advances in resin technology are offered in Chapters 5 and 6, which constitute the first comprehensive accounts of (meth)acrylated silicones and vinyl ethers, respectively. Radiation-curable coatings, printing inks, and adhesives are discussed in Chapters 7-9, respectively. Chapter 10 offers a discussion on photopolymer imaging systems

  7. UV-cured polymer optics

    Science.gov (United States)

    Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

    2017-10-01

    Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

  8. Behaviors of nitrite in cured meat

    International Nuclear Information System (INIS)

    Miwa, Misao

    1980-01-01

    The behaviors of nitrite in cured meat were studied by means of 15 N on the basis of the gaseous 15 N volume from the added nitric acid. The myoglobin, 15 N-nitrite and ascorbate model systems showed a 15 N recovery rate of approximately 100%, but actual meat samples, treated similarly, showed a recovery rate ranging from 66 to 90%, with formation of an unidentified 15 N agent. The largest amount of this unidentified agent was obtained by reaction of the 0.05 M NaCl-soluble dialyzable fraction of meat with 15 N-nitrite. When the reaction product was isolated by Sephadex column chromatography, 15 N in the fraction, which was thought to be the agent, contained approximately 26% of the added 15 N, possessed no UV absorption, and was negative for a ninhydrin reagent. Of the NaCl soluble fraction, reaction in the acidic fraction produced the largest quantity of the unidentified 15 N compound (31% of the added 15 N). This compound was strongly acidic and consisted of 30.7% C, 6.6% H and 4.9% N on element analysis. It showed no mutagenicity against Salmonella by Ames Test. (Chiba, N.)

  9. Cure Schedule for Stycast 2651/Catalyst 9.

    Energy Technology Data Exchange (ETDEWEB)

    Kropka, Jamie Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); McCoy, John D. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2017-11-01

    The Emerson & Cuming technical data sheet (TDS) for Stycast 2651/Catalyst 9 lists three alternate cure schedules for the material, each of which would result in a different state of reaction and different material properties. Here, a cure schedule that attains full reaction of the material is defined. The use of this cure schedule will eliminate variance in material properties due to changes in the cure state of the material, and the cure schedule will serve as the method to make material prior to characterizing properties. The following recommendation uses one of the schedules within the TDS and adds a “post cure” to obtain full reaction.

  10. Nickel/zinc-catalyzed decarbonylative addition of anhydrides to alkynes: a DFT study.

    Science.gov (United States)

    Meng, Qingxi; Li, Ming

    2013-10-01

    Density functional theory (DFT) was used to investigate the nickel- or nickel(0)/zinc- catalyzed decarbonylative addition of phthalic anhydrides to alkynes. All intermediates and transition states were optimized completely at the B3LYP/6-31+G(d,p) level. Calculated results indicated that the decarbonylative addition of phthalic anhydrides to alkynes was exergonic, and the total free energy released was -87.6 kJ mol(-1). In the five-coordinated complexes M4a and M4b, the insertion reaction of alkynes into the Ni-C bond occurred prior to that into the Ni-O bond. The nickel(0)/zinc-catalyzed decarbonylative addition was much more dominant than the nickel-catalyzed one in whole catalytic decarbonylative addition. The reaction channel CA→M1'→T1'→M2'→T2'→M3a'→M4a'→T3a1'→M5a1' →T4a1'→M6a'→P was the most favorable among all reaction pathways of the nickel- or nickel(0)/zinc- catalyzed decarbonylative addition of phthalic anhydrides to alkynes. And the alkyne insertion reaction was the rate-determining step for this channel. The additive ZnCl2 had a significant effect, and it might change greatly the electron and geometry structures of those intermediates and transition states. On the whole, the solvent effect decreased the free energy barriers.

  11. A sulfonic anhydride derivative from dibenzyl trisulphide with agro-chemical activities.

    Science.gov (United States)

    Williams, L A D; Vasquez, E; Klaiber, I; Kraus, W; Rosner, H

    2003-06-01

    In the present study, the biologically active natural product dibenzyl trisulphide (DTS) which was previously isolated from the sub-tropical shrub Petiveria alliacea was transformed to methyl benzyl sulphonic anhydride (MBSA) using a "one pot" transformation method. The anhydride was evaluated for anti-microbial activities on the bacteria, Bacillus subtilis and Pseudomonas fluorescens and found to be 2.5 fold more effective than the commercial agents isoniazid and ampicillin in inhibiting the growth of B. subtilis, while on P. fluorescens it was 2.5, 5.0 and 10.0 fold more inhibitory than isoniazid, ampicillin and dibenzyl trisulphide, respectively. DTS was inactive on B. subtillis. The MIC value (microgram/spot) found for DTS on the plant pathogenic fungus, Cladosporium cucumerinum was 5.0 microgram/spot, while MBSA gave a value of 0.1 microgram/spot, compared with 1.25 and 0.16 microgram/spot for the commercial agents ketoconazole and nystatin, respectively. On the larval nematode (Meloidogyne incognita) MBSA inflicted 97.72% and 57.47% Abbotts nematicidal activities at 125.0 and 62.5 ppm, respectively, while DTS had no effect at 125.0 ppm. Nematodes which were immobilized by the low concentrations of MBSA were unable to re-activate when exposed to 10.0 ppm picrotoxin, thus suggesting that the anhydride nematicidal activity is independent of the GABA-ergic neurophysiological pathway.MBSA demonstrated a strong dose dependent radicular suppression effect (r=0.984), on the radicles of Latuca sativa germinating seeds. DTS was weakly active.

  12. Dielectric Cure Monitoring of Thermosetting Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyoung Geun [Agency for Defense Development, Daejeon (Korea, Republic of); Lee, Dae Gil [KAIST, Daejeon (Korea, Republic of)

    2003-10-15

    Cure monitoring can be used to improve the quality and productivity of thermosetting resin matrix composite products during their manufacturing process. In this work, the sensitivity of dielectrometry was improved by adequate separation the efforts of sensor and externals on the measured signal. A new algorithm to obtain the degree of cure during dielectric cure monitoring of glass/polyester and glass/epoxy composites was developed by employing a function of both temperature and dissipation factor, in which five cure monitoring parameters were used to calculate the degree of cure. The decreasing pattern of dissipation factor was compared with the relationships between the degree of cure and the resin viscosity. The developed algorithm might be employed for the in situ cure monitoring of thermosetting resin composites

  13. Dielectric Cure Monitoring of Thermosetting Matrix Composites

    International Nuclear Information System (INIS)

    Kim, Hyoung Geun; Lee, Dae Gil

    2003-01-01

    Cure monitoring can be used to improve the quality and productivity of thermosetting resin matrix composite products during their manufacturing process. In this work, the sensitivity of dielectrometry was improved by adequate separation the efforts of sensor and externals on the measured signal. A new algorithm to obtain the degree of cure during dielectric cure monitoring of glass/polyester and glass/epoxy composites was developed by employing a function of both temperature and dissipation factor, in which five cure monitoring parameters were used to calculate the degree of cure. The decreasing pattern of dissipation factor was compared with the relationships between the degree of cure and the resin viscosity. The developed algorithm might be employed for the in situ cure monitoring of thermosetting resin composites

  14. MECHANICAL, ELECTRICAL, AND THERMAL PROPERTIES OF MALEIC ANHYDRIDE MODIFIED RICE HUSK FILLED PVC COMPOSITES

    OpenAIRE

    Navin Chand; Bhajan Das Jhod

    2008-01-01

    Unmodified and modified rice husk powder filled PVC composites were prepared having different amounts of rice husk powder. Mechanical, thermal, and electrical properties of these composites were determined. The tensile strength of rice husk powder PVC composites having 0, 10, 20, 30, and 40 weight percent of rice husk powder was found to be 33.9, 19.4, 18.1, 14.6, and 9.5 MPa, respectively. Adding of maleic anhydride- modified rice husk powder improved the tensile strength of rice husk powder...

  15. Purifying, concentrating and anhydriding bio-ethanol: Alternative process schemes and innovative separation methods

    International Nuclear Information System (INIS)

    Guerreri, G.; Lovati, A.

    1992-01-01

    Starting with the conventional process scheme for bio-ethanol production, this paper illustrates how the anhydriding section, which incorporates an azeotropic distillation process, can be conveniently substituted with a plate and frame pervaporation process which makes use of optimum heat exchange with the stripping section. This technical feasibility study, which proves the superior energy efficiency of the pervaporation scheme as compared with the conventional scheme, is followed by a cost benefit analysis which evidences the economic benefits also to be had with pervaporation

  16. Synthesis, Characterization and Curing Studies of Thermosetting Epoxy Resin with Amines

    International Nuclear Information System (INIS)

    Lakshmi, B.; Mahendra, K. N.; Shivananda, K. N.

    2010-01-01

    A new hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) is prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with Epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possesses both the oxirane ring and maleimide group. The curing reaction of these maleimidophenyl glycidylether epoxy compound (N-MPGE) with amines as curing agents such as ethylendiamine (EDA), diethylentriamine (DETA) and triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine, IPDA), are studied. Incorporation of maleimide groups in the epichlorohydrin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples exhibited good thermal stability, excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity net work of the cured systems

  17. Synthesis, Characterization and Curing Studies of Thermosetting Epoxy Resin with Amines

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmi, B.; Mahendra, K. N. [Bangalore University, Bangalore (India); Shivananda, K. N. [Technion - Israel Institute of Technology, Haifa (Israel)

    2010-08-15

    A new hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) is prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with Epichlorohydrin by using benzyltrimethylammonium chloride as a catalyst. The resulting compound possesses both the oxirane ring and maleimide group. The curing reaction of these maleimidophenyl glycidylether epoxy compound (N-MPGE) with amines as curing agents such as ethylendiamine (EDA), diethylentriamine (DETA) and triethylenetetramine (TETA), aminoethylpiperazine (AEP) and isophoronediamine, IPDA), are studied. Incorporation of maleimide groups in the epichlorohydrin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples exhibited good thermal stability, excellent chemical (acid/alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity net work of the cured systems.

  18. Comparative Study Of The Preparation Of Maleic Anhydride-g-Polypropylene By Two Grafting Processes Using Peroxide

    International Nuclear Information System (INIS)

    Sakahara, R.M.; Wang, S.H.

    2010-01-01

    The Polypropylene grafting with Maleic anhydride is a thoroughly known technique. Its wide application is due, mainly,to the controlled changing in the polarity of this polymer, which increases the interfacial adhesion in blends and compounds. In this study, two grafting processes were compared. In the first, the maleic anhydride was grafted on polypropylene in a solution batch process, carried out in a round-bottom vessel. The second approach was carried out by reactive extrusion of polypropylene in the presence of peroxide and maleic anhydride. The samples thus prepared were characterized by DSC, TGA, FTIR, WAXS, EDS e SEM. It was possible to conclude that the solution technique was more efficient than the reactive extrusion; however the later was easier to accomplish due to the high viscosity of PP. (author)

  19. Electron beam curing of EPDM

    International Nuclear Information System (INIS)

    Vroomen, G.L.M.; Visser, G.W.; Gehring, J.

    1991-01-01

    Normally EPDM rubbers are vulcanized by systems based on sulphur, resin or peroxide. The common feature of these systems is that they all require activator energy in the form of heat. The (extremely) high temperatures (approximately 180C) have the disadvantage that the final properties of the finished product may be affected in one way or another by a variety of uncontrolled side reactions which may occur. Radiation curing, on the other hand, is a process which differs from those mentioned above in that the final curing is carried out at about 20C under closely controlled conditions (such as radiation dose, penetration depth, etc.), and this form of curing ultimately results in a more well-defined end product. In the rubber industry, this technique is used by large rubber processors (for example, in roof sheeting and cable production). Its widespread use is, however, impeded by the high investment costs. One way of avoiding these high costs is to arrange for the products to be irradiated by contractors. The optimum radiation dose for EPDM is determined by the required pattern of properties. From this study it may be concluded that the network is primarily built up at a radiation dose of up to approximately 100 kGy. The degree to which it is built up depends partly on the coactivator used and the EPDM type used. In choosing the coactivator, allowance has to be made for its solubility in EPDM. The type of oil chosen and any stabilizer additions will affect the crosslinking efficiency. Contrary to studies published earlier, in this study it was found that when EDMA is used as a coactivator, no difference can be detected between a DCPD type (4%) and an ENB type (4%), provided both have an identical molecular weight distribution. Increasing the ENB content has less effect on the final crosslink density than using a type having a broader molecular weight distribution

  20. Use of alternative curing salts for processing salamis

    Directory of Open Access Journals (Sweden)

    Dong-Gyun Yim

    2018-01-01

    Full Text Available Objective This study was performed to determine effects of different curing salts on the quality of salamis and to assess feasibility of using NaCl-alternative salts. Methods Various types of curing salts (KCl or MgCl2 as well as NaCl (sun-dried or refined were incorporated for processing of salamis. The proximate composition, fatty acids, nucleotide-related compounds, and free amino acids of the salamis were analyzed during 40 days of ripening. Results The substitution of NaCl by KCl caused higher fat and ash content, but lower moisture content of the salami after 20 days of ripening (p<0.05. Compared with the sun-dried NaCl, use of KCl in salami also led to greater inosine 5′-monophosphate whereas refined NaCl had more inosine (p<0.05. KCl-added salami also had a higher C12:0, C17:1, and C20:0 than other types of salami (p<0.05. MgCl2-added salami had higher content of free amino acids compared to the other salamis (p<0.05. Conclusion Alternative curing salts such as KCl and MgCl2 could substitute NaCl in consideration of quality factor of a fermented meat product. Especially replacement of NaCl with KCl will be a suitable strategy for developing relatively low sodium salami products without compromising product quality.

  1. Removal of Copper ions from aqueous solutions using polymer derivations of poly (styrene-alt-maleic anhydride

    Directory of Open Access Journals (Sweden)

    Naser Samadi

    2017-06-01

    Full Text Available In this study chelating resins have been considered to be suitable materials for the recovery of Copper (II ions in water treatments. Furthermore, these modified resins were reacted with 1,2-diaminoethane in the presence of ultrasonic irradiation for the preparation of a tridimensional chelating resin on the Nano scale for the recovery of Copper (II ions from aqueous solutions. This method which is used for removing and determining Copper (II ions using copolymers derived resins of poly (styrene-alternative-maleic anhydride (SMA and atomic absorption spectroscopy. The method is simple, sensitive, inexpensive and fast. The various parameters such as pH, contact time, concentrations of metal ions, mass of resin, and agitation speed were investigated on adsorption effect. The adsorption behavior of Copper (II ions were investigated by the synthesis of chelating resins at various pHs. The prepared resins showed a good tendency for removing the selected metal ions from aqueous solution, even at an acidic pH. Also, the prepared resins were examined for the removal of Copper (II ions from real samples such as industrial wastewater and were shown to be very efficient at adsorption in the cases of Copper (II ions. The pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetics equations were used for modeling of adsorption data and it was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. The intra-particle diffusion study revealed that external diffusion might be involved in this case. The resins were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis.

  2. Effects of Different Types of Clays and Maleic Anhydride Modified Polystyrene on Polystyrene/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Mehrabzadeh

    2013-01-01

    Full Text Available Polymer/clay nanocomposites are considered as a new subject of research in Iran and the world. Addition of a minimum amount of clay (2-5wt% can improve the mechanical properties, enhance barrier properties and reduce flammability dramatically. Polystyrene (PS exhibits high strength, high modulus and excellent dimensional stability, but it has poor ductility, elongation, and flexural modulus. By incorporating clay into polystyrene these properties can be improved. In this study preparation of polystyrene/clay nanocomposite, effects of different types of clays (Cloisite 10A andNanomer I.30TC and maleic anhydride modified polystyrene on mechanical properties of the prepared polystyrene/clay nanocomposites were evaluated. Samples were prepared by a twin screw extruder. Transmission electron microscopy (TEM and X-ray diffraction (XRD techniques were employed to evaluate the extent of intercalation and exfoliation of silicate layers in the nanocomposites. Mechanical tests show that by addition of clay and maleic anhydride modified polystyrene the flexural modulus (~30% and elongation-at-break (~40% of prepared nanocomposites have been improved. XRD and TEM results show that nanocomposite have an intercalated structure with ability to change to further exfoliation structure.

  3. Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light emitting diodes

    Science.gov (United States)

    Rider, N. D.; Taha, Y. M.; Odame-Ankrah, C. A.; Huo, J. A.; Tokarek, T. W.; Cairns, E.; Moussa, S. G.; Liggio, J.; Osthoff, H. D.

    2015-01-01

    Photochemical sources of peroxycarboxylic nitric anhydrides (PANs) are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg) lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone) in the presence of a calibrated amount of nitric oxide (NO) and oxygen (O2). In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs) is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). Using acetone, diethyl ketone (DIEK), diisopropyl ketone (DIPK), or di-n-propyl ketone (DNPK), respectively, the source produces peroxyacetic (PAN), peroxypropionic (PPN), peroxyisobutanoic (PiBN), or peroxy-n-butanoic nitric anhydride (PnBN) from NO in high yield (> 90%). Box model simulations with a subset of the Master Chemical Mechanism (MCM) were carried out to rationalize products yields and to identify side products. The use of UV-LED arrays offers many advantages over conventional Hg lamp setups, including greater light output over a narrower wavelength range, lower power consumption, and minimal generation of heat.

  4. Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light-emitting diodes

    Science.gov (United States)

    Rider, N. D.; Taha, Y. M.; Odame-Ankrah, C. A.; Huo, J. A.; Tokarek, T. W.; Cairns, E.; Moussa, S. G.; Liggio, J.; Osthoff, H. D.

    2015-07-01

    Photochemical sources of peroxycarboxylic nitric anhydrides (PANs) are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg) lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone) in the presence of a calibrated amount of nitric oxide (NO) and oxygen (O2). In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs) is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC) and thermal dissociation cavity ring-down spectroscopy (TD-CRDS). Using acetone, diethyl ketone (DIEK), diisopropyl ketone (DIPK), or di-n-propyl ketone (DNPK), respectively, the source produces peroxyacetic (PAN), peroxypropionic (PPN), peroxyisobutanoic (PiBN), or peroxy-n-butanoic nitric anhydride (PnBN) from NO in high yield (> 90 %). Box model simulations with a subset of the Master Chemical Mechanism (MCM) were carried out to rationalize product yields and to identify side products. The present work demonstrates that UV-LED arrays are a viable alternative to current Hg lamp setups.

  5. Highly Efficient Fumed Silica Nanoparticles for Peptide Bond Formation: Converting Alanine to Alanine Anhydride.

    Science.gov (United States)

    Guo, Chengchen; Jordan, Jacob S; Yarger, Jeffery L; Holland, Gregory P

    2017-05-24

    In this work, thermal condensation of alanine adsorbed on fumed silica nanoparticles is investigated using thermal analysis and multiple spectroscopic techniques, including infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopies. Thermal analysis shows that adsorbed alanine can undergo thermal condensation, forming peptide bonds within a short time period and at a lower temperature (∼170 °C) on fumed silica nanoparticle surfaces than that in bulk (∼210 °C). Spectroscopic results further show that alanine is converted to alanine anhydride with a yield of 98.8% during thermal condensation. After comparing peptide formation on solution-derived colloidal silica nanoparticles, it is found that fumed silica nanoparticles show much better efficiency and selectivity than solution-derived colloidal silica nanoparticles for synthesizing alanine anhydride. Furthermore, Raman spectroscopy provides evidence that the high efficiency for fumed silica nanoparticles is likely related to their unique surface features: the intrinsic high population of strained ring structures present at the surface. This work indicates the great potential of fumed silica nanoparticles in synthesizing peptides with high efficiency and selectivity.

  6. Selective oxidation of n-butane to maleic anhydride under oxygen-deficient conditions over V-P-O mixed oxides

    NARCIS (Netherlands)

    Bosch, H.; Bruggink, A.A.; Ross, J.R.H.

    1987-01-01

    The selective oxidation of n-butane to maleic anhydride over V-P-O mixed oxides was studied under oxygen deficient conditions. The mixed oxides were prepared with P/V atomic ratios ranging from 0.7 to 1.0. Catalysts with P/V <1.0 did not show any selectivity to maleic anhydride formation, regardless

  7. Radiation cured silicone rubber articles

    International Nuclear Information System (INIS)

    DuPont, J.G.; Goodwin, P.A.

    1984-01-01

    A process for making radiation cured silicone rubber articles is disclosed wherein a hydroxyl-terminated polysilaxane having a molecular weight from about 50,000 to about 2,000,000, optionally modified by mixing with up to 85% of an end-stopped silicone rubber, is mixed with from about 10 to about 70 parts per hundred of rubber of a finely divided silica filler with a particle size in the reinforcing range and other inert fillers as determined by desired final properties; the composition so prepared is formed into the desired shape at room temperature; the article so formed is precured to improve the mechanical properties of the material with which it is made by exposure to ammonia gas, ammonium hydroxide, or to the vapors or solutions of a volatile amine at room temperature; and the precured article is irradiated with high energy electrons or gamma radiation to effect a permanent cure of the material from which the article is formed

  8. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites.

    Science.gov (United States)

    Invernizzi, Marta; Natale, Gabriele; Levi, Marinella; Turri, Stefano; Griffini, Gianmarco

    2016-07-16

    Glass (GFR) and carbon fiber-reinforced (CFR) dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D) printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C) thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride) as hardener and (2,4,6,-tris(dimethylaminomethyl)phenol) as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  9. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites

    Directory of Open Access Journals (Sweden)

    Marta Invernizzi

    2016-07-01

    Full Text Available Glass (GFR and carbon fiber-reinforced (CFR dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride as hardener and (2,4,6,-tris(dimethylaminomethylphenol as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  10. Ultrasound-assisted catalytic synthesis of acyclic imides in the presence of p-toluenesulfonic acid under solvent free conditions

    Directory of Open Access Journals (Sweden)

    Nasr-Esfahani Masoud

    2012-01-01

    Full Text Available A rapid and convenient preparation of acyclic imides by the reaction of aliphatic and aromatic nitriles with acyclic carboxylic anhydride in the presence of catalytic amounts of p-toluenesulfonic acid under thermal or ultrasonic conditions is reported. The advantages of this procedure are moderate reaction times, good to excellent yields, use of inexpensive and ecofriendly catalyst. The reaction of nitriles with aliphatic anhydrides proceeds in thermal conditions, while by the use of ultrasound irradiations these reactions get accelerated.

  11. UV/EB curing market in Indonesia

    International Nuclear Information System (INIS)

    Hilmy, N.; Danu, S.

    1999-01-01

    The most application of UV curing of surface coating in Indonesia are on fancy plywood, furniture and wood flooring industry. Other application are on papers, printing ink/labelling, printed circuit board/PCB and dental materials. At present, application of EB curing coating is still in a pilot plant scale due to the high cost of production. Limited number of application of EB curing by using low energy electron beam machine are on wood panels, ceramics and marbles. This paper describes the market and the problem faced by the largest user of radiation curing systems such as the secondary process plywood, furniture and paper industries

  12. Curing efficiency of three light emitting diode units at different curing profiles

    Directory of Open Access Journals (Sweden)

    Priyanka Verma

    2016-01-01

    Conclusions: Reduction of exposure time to 6 s with high-intensity curing light seemed to be clinically acceptable and should be recommended. Curing of metal brackets with single exposure from buccal side showed lower shear bond strength values.

  13. Pre-cure freezing affects proteolysis in dry-cured hams.

    Science.gov (United States)

    Bañón, S; Cayuela, J M; Granados, M V; Garrido, M D

    1999-01-01

    Several parameters (sodium chloride, moisture, intramuscular fat, total nitrogen, non-protein nitrogen, white precipitates, free tyrosine, L* a* b* values and acceptability) related with proteolysis during the curing were compared in dry-cured hams manufactured from refrigerated and frozen/thawed raw material. Pre-cure freezing increased the proteolysis levels significantly (pcured meat, although it does not significantly affect the sensory quality of the dry-cured ham.

  14. Prevention is better than cure

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    Throughout the year, members of the Safety Inspections Services section of HSE Unit devote themselves to ensuring the safety of all infrastructure and equipment that represent a specific hazard within the Organization. They regularly comb through all CERN's infrastructure to forestall any accidents and their potential impact, true to the adage that prevention is better than cure.   This site has a few (!) slight safety problems... Spot the mistakes! (Details of the game below.) Ensuring that an HV electrical installation is properly earthed, that a system under pressure has no weak points, that an item of lifting equipment can be used without risk, that safety valves operate at the right pressure threshold as well as checking that a heavy object that could inflict injury if it fell is not stored on top of a cupboard: such are the types of inspections performed by the Safety Inspection Service (DGS-SEE-SIS). "These checks reassure those in charge of equipment and infrastruct...

  15. Theoretical problems associated with the use of acetic anhydride as a co-solvent for the non-aqueous titration of hydrohalides of organic bases and quaternary ammonium salts.

    Science.gov (United States)

    Völgyi, Gergely; Béni, Szabolcs; Takács-Novák, Krisztina; Görög, Sándor

    2010-01-05

    A potentiometric titration study of organic base hydrohalides and quaternary ammonium salts using perchloric acid as the titrant and a mixture of acetic anhydride and acetic acid as the solvent was carried out and the titration mixture was analysed by NMR in order to clarify the chemistry of the reactions involved. It was found that in contrast to the general belief the formation of acetyl halides and titratable free acetate ion does not take place prior to the titration but NMR spectra proved the formation of acetyl halides in the course of the titration. This observation and the fact that the shape of the titration curves depends on the nature of the hydrohaloic acid bound to the base or of the anion in the quaternary ammonium salts led to the conclusion that the titrating agent is acetyl perchlorate formed in situ during the titration. Equations of the reactions involved in the titration process are shown in the paper.

  16. Influence of pre-cure freezing of Iberian ham on proteolytic changes throughout the ripening process.

    Science.gov (United States)

    Pérez-Palacios, Trinidad; Ruiz, Jorge; Barat, Jose Manuel; Aristoy, María Concepción; Antequera, Teresa

    2010-05-01

    This work aimed to investigate the effect of pre-cure freezing Iberian hams on proteolysis phenomena throughout the ripening process. Non-protein nitrogen (NPN), peptide nitrogen (PN) and amino acid nitrogen (AN) as well as amino acid and dipeptide evolution followed the same trend in both refrigerated (R) and pre-cure frozen (F) Iberian hams during processing. At the different stages of ripening, there were no differences in the content of NPN and AN while F dry-cured hams had higher levels of PN than R hams at the final step. This seemed to be more related to the salt content (lower in F than in R hams) than to the pre-cure freezing treatment. Most amino acids and dipeptides detected showed higher concentrations in F than in R Iberian hams at the green stage, being rather similar at the intermediate phases. At the final stage, the effects of pre-cure freezing of Iberian hams were not well defined, higher levels of some amino acids and dipeptides were found in R than in F Iberian hams whereas other amino acids were lower in R than in F hams. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  17. The use of maleic anhydride-modified polypropylene for performance enhancement in continuous glass fiber-reinforced polypropylene composites

    NARCIS (Netherlands)

    Rijsdijk, H.A.; Contant, M.; Peijs, A.A.J.M.; Miravete, A.

    1993-01-01

    The influence of maleic anhydride-modified polypropylene (m-PP) on static mech. properties of continuous glass fiber-reinforced polypropylene (PP) composites was studied. M-PP was added to the PP homopolymer to improve the adhesion between the matrix and the glass fiber. Three-point bending tests

  18. Kinetics of Hydrolysis of Acetic Anhydride by In-Situ FTIR Spectroscopy: An Experiment for the Undergraduate Laboratory

    Science.gov (United States)

    Haji, Shaker; Erkey, Can

    2005-01-01

    A reaction kinetics experiment for the chemical engineering undergraduate laboratory course was developed in which in-situ Fourier Transfer Infrared spectroscopy was used to measure reactant and product concentrations. The kinetics of the hydrolysis of acetic anhydride was determined by experiments carried out in a batch reactor. The results…

  19. Characterization of derivates of carbo-anhydride by NMR; Caracterizacao de derivados do anidrido carbico por RMN

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Marcos Pery Amaral [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Bergter, Lothar [Cia. Souza Cruz, Rio de Janeiro, RJ (Brazil); Seidl, Peter Rudolf [Centro de Tecnologia Mineral, Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The term molecular recognition may be applied to several phenomena of different complexities. The compounds which work as blockers or acceptors in this process are generally complexes with functional groups positioned in specific positions. This work presents the NMR characterization of carbo-anhydride derivates which are important in the preparation of synthetic acceptors 2 figs.

  20. RAFT copolymerization of itaconic anhydride and 2-methoxyethyl acrylate: a multifunctional scaffold for preparation of “clickable” gold nanoparticles

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Kasama, Takeshi; Jankova, Katja Atanasova

    2013-01-01

    RAFT copolymerization of 2-methoxyethyl acrylate and itaconic anhydride – a monomer derived from renewable resources – is carried out in a controlled fashion. The copolymer allows preparation of gold nanoparticles with abundant surficial carboxyl and alkyne functional groups that are dendronized...

  1. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amides, from ammonium hydroxide... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... subject to reporting. (1) The chemical substance identified as amides, from ammonium hydroxide - maleic...

  2. Seasonal variations of monosaccharide anhydrides in PM1 and PM2.5 aerosol in urban areas

    Czech Academy of Sciences Publication Activity Database

    Křůmal, Kamil; Mikuška, Pavel; Vojtěšek, Martin; Večeřa, Zbyněk

    2010-01-01

    Roč. 44, č. 39 (2010), s. 5148-5155 ISSN 1352-2310 R&D Projects: GA MŽP SP/1A3/148/08 Institutional research plan: CEZ:AV0Z40310501 Keywords : monosaccharide anhydrides * biomass burning * levoglucosan Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.226, year: 2010

  3. Accelerated Cure Project for Multiple Sclerosis

    Science.gov (United States)

    ... questions and enable an era of optimized MS treatment. Read more... The Accelerated Cure Project for MS is a non-profit, 501(c)(3) tax-exempt organization whose mission is to accelerate efforts toward a cure for multiple sclerosis by rapidly advancing research that determines its causes ...

  4. Radiation cured acrylonitrile--butadiene elastomers

    International Nuclear Information System (INIS)

    Eldred, R.J.

    1976-01-01

    In accordance with a preferred embodiment of this invention, the ultimate elongation of an electron beam radiation cured acrylonitrile-butadiene elastomer is significantly increased by the incorporation of a preferred noncrosslinking monomer, glycidyl methacrylate, in combination with the conventional crosslinking monomer, trimethylolpropanetrimethacrylate, prior to the radiation curing process

  5. Hard facts for radiation curing of elastomers

    International Nuclear Information System (INIS)

    Lyall, D.J.

    1984-01-01

    The subject is covered under the headings: introduction; outline of chemistry (differences between conventional and radiation curing); compounding; green strength; response of rubbers to electron beam treatment; electron beam cured applications:(a) wire and cable applications;(b) rubber tyre components;(c) heat shrinkable materials;(d) roofing materials. (U.K.)

  6. Translating Genomic Discoveries to Cure Ultrahypermutant ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Translating Genomic Discoveries to Cure Ultrahypermutant Mismatch Repair Deficient Brain Tumours. Malignant brain tumours are the most common cause of death among children with cancer, but there is no known cure. This project will advance research in this important field. Inherited mutations and childhood cancer.

  7. Oil recovery with sulfomethylated poly (lower alkyl vinyl ether/maleic anhydride)

    Energy Technology Data Exchange (ETDEWEB)

    Norton, C.J.; Falk, D.O.

    1973-05-22

    Lower alkyl vinyl ether e.g., methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, hexyl vinyl ether, is copolymerized conventionally with maleic anhydride, the resulting copolymer is treated with ammonia or ammonium hydroxide to form the partial amide-ammonium salt, and this salt is in turn treated with formaldehyde and thereafter or simultaneously with ammonium or alkali metal salt sulfite (including bisulfites, etc.) to form an at least partially sulfomethylated copolymer. Aqueous solutions of the sulfomethylated copolymer are useful in increasing the viscosity of drive fluids used in the supplemented recovery of petroleum from subterranean formations. In general, enhancing the polyionic character of mobility control agents used in supplemented recovery of petroleum provides enhanced recovery. Achieving this enhancement of polyionic character through use of sulfonate groups provides a mobility control agent with good ability to sustain viscosity in the presence of brine and lime, usually present in the connate waters of petroleum-bearing formations. (7 claims)

  8. Surface Functionalization of WO3 Thin Films with (3-Aminopropyl)triethoxysilane and Succinic Anhydride

    Science.gov (United States)

    Ta, Thi Kieu Hanh; Tran, Thi Nhu Hoa; Tran, Quang Minh Nhat; Pham, Duy Phong; Pham, Kim Ngoc; Cao, Thi Thanh; Kim, Yong Soo; Tran, Dai Lam; Ju, Heongkyu; Phan, Bach Thang

    2017-06-01

    We report effects of oxygen plasma treatment on the surface functionalization of WO3 thin films with (3-aminopropyl)triethoxysilane (APTES) and succinic anhydride (SA). X-ray diffraction and x-ray photoelectron spectroscopy results indicate the existence of the WO3 phase. Fourier transform infrared spectroscopy measurement shows clear bands at 1040 cm-1 (Si-O-Si), 1556 cm-1 (N-H), 1655 cm-1 (C=O), 2937 cm-1 (C-H) and 3298 cm-1 (N-H), confirming the surface functionalization efficiency enhanced by prior treatment of oxygen plasma. It thus follows that the prior oxygen plasma treatment activates hydroxylation with more -OH groups on the WO3 surface, which can pave a highly efficient way to the surface functionalization by APTES and SA.

  9. Physico-mechanical properties of silanized-montmorillonite reinforced chitosan-co-poly(maleic anhydride) composites

    Science.gov (United States)

    Saputra, O. A.; Fajrin, A.; Nauqinida, M.; Suryanti, V.; Pramono, E.

    2017-07-01

    To solve the problems of dependence on petroleum as starting material in the manufacturing of plastics in Indonesia, green plastic from biopolymer like chitosan to be one of promising options and alternative to replace the conventional plastics. However, to overcome the mechanical and physical properties of chitosan, the addition of reinforcement agent was introduced. In this study, silanized-montmorillonite (sMMt) has been prepared as a reinforcement agent in the chitosan-co-poly(maleic anhydride) (referred as Cs-MAH) matrix. Silanizing of montmorillonite is one of strategy to improve the interaction between montmorillonite and chitosan, consequently, the mechanical properties, tensile strength of composites contained 6 phr of sMMt improved 56.5% to chitosan. Moreover, the presence both MAH and sMMt on the comosites also reduced swelling degree and swelling area by 20.6% and 26.7%.

  10. Pulmonary hemorrhage and edema due to inhalation of resins containing tri-mellitic anhydride.

    Science.gov (United States)

    Herbert, F A; Orford, R

    1979-11-01

    Seven young men developed acute pulmonary hemorrhage and edema from the inhalation of powder or fumes of a bisphenol epoxy resin containing tri-mellitic anhydride (TMA) while working in a steel pipe-coating plant. The illness was characterized by cough, hemoptysis, dyspnea, fever, weakness and nausea or vomiting. Chest roentgenograms showed either a bilateral or unilateral pulmonary infiltrate. All patients had a normochromic type of anemia. Pulmonary function studies demonstrated a restrictive defect, hypoxemia, and increased A-a DO2 gradients. Light and electron microscopic studies of lung tissue revealed extensive bleeding into alveoli but no basement membrane deposits were seen and no antiglomerular basement membrane antibodies were detected. The patients improved quickly without treatment. Follow-up studies of six patients three weeks to one year after their illness revealed apparent recovery. A detailed medical survey carried out on all 29 workers currently employed in the plant revealed five additional men had experienced severe recurrent pulmonary problems.

  11. Vibrational, electronic and quantum chemical studies of 1,2,4-benzenetricarboxylic-1,2-anhydride.

    Science.gov (United States)

    Arjunan, V; Raj, Arushma; Subramanian, S; Mohan, S

    2013-06-01

    The FTIR and FT-Raman spectra of 1,2,4-benzenetricarboxylic-1,2-anhydride (BTCA) have been recorded in the range 4000-400 and 4000-100 cm(-1), respectively. The complete vibrational assignments and analysis of BTCA have been performed. More support on the experimental findings was added from the quantum chemical studies performed with DFT (B3LYP, MP2, B3PW91) method using 6-311++G(**), 6-31G(**) and cc-pVTZ basis sets. The structural parameters, energies, thermodynamic parameters, vibrational frequencies and the NBO charges of BTCA were determined by the DFT method. The (1)H and (13)C isotropic chemical shifts (δ ppm) of BTCA with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. The delocalization energies of different types of interactions were determined. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Study of maleic anhydride and styrene grafted onto polypropylene induced by UV irradiation

    International Nuclear Information System (INIS)

    Li Zhenzhong; He Wei; Guo Hongjun; Zhang Wenxiong; Ma Yalin

    2007-01-01

    Maleic anhydride (MAH) and styrene (St) grafted onto polypropylene (PP) were prepared by UV irradiation. Effects of the irradiation time, monomer and initiator content on the grafting rate and melt flow rate (MFR) were studied. The results show that the optimal duration of UV irradiation is 30s. The grafting rate increases with initiator content when initiator content less than 0.6 phr, the MFR value of grafted PP reaches the highest point when benzophenone (BP) content is 0.4 phr. The content of MAH and St have an effect on the grafting rate and MFR value of the grafted PP, and the optimal contents of monomer is 4 phr. The existence of St as a comonomer reduces apparently the MFR value of grafted PP greatly. Grafted PP present significant changes in crystallization and fusion peaks, indicating differences in crystal size and formation after grafting reaction. (authors)

  13. nanocomposites of PA6/ABS blends compatibilized with styrene-maleic anhydride copolymer

    International Nuclear Information System (INIS)

    Oliveira, Amanda D. de; Pessan, Luiz A.

    2009-01-01

    To achieve a balance between stiffness and toughness, ternary nanocomposites based on blends of polyamide 6 (PA6) and acrylonitrile-butadiene-styrene (ABS) were prepared by the melt intercalation using the organoclay Cloisite R 30B (OMMT) and the styrene-maleic anhydride copolymer (SMA) as compatibilizer. Four blending sequences were used to prepare studied systems and their mechanical properties studied through the Young's modulus and notched Izod impact. It was observed that the materials prepared by all blending sequences studied showed an increase in the Young's modulus compared to the neat PA6. However, a decrease in the toughness was observed for the systems with the addition of the organoclay. The DRX results showed an intercalated structure for the some systems that used ABS in their compositions. HDT measurements of the nanocomposites showed an increase in this property compared to the neat PA6. The use of nanoclay lead to a reinforcement of the polymeric matrix. (author)

  14. Maleic anhydride as an additive to γ-butyrolactone solutions for Li-ion batteries

    International Nuclear Information System (INIS)

    Ufheil, Joachim; Baertsch, Martin C.; Wuersig, Andreas; Novak, Petr

    2005-01-01

    The effect of maleic anhydride (MA) as a new film-forming additive in γ-butyrolactone (GBL)-based electrolytes for use in Li-ion batteries has been studied to advance the understanding of the solid electrolyte interphase (SEI) formation on graphite electrodes. Cyclic voltammetry measurements showed that even small amounts of MA (up to 4 wt.%) improved the lithium intercalation into graphite. The effect of MA was also verified by electrochemical impedance spectroscopy. In situ subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS) and differential electrochemical mass spectrometry (DEMS) allowed identification of gas formation and decomposition products during the SEI formation. GBL-based electrolytes with MA showed both, higher cycling efficiency and cycle life of graphite electrodes

  15. EB/UV curing market in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, Khairul Zaman; Nik Salleh, Nik Ghazali; Mahmood, Mohd Hilmi [Malaysian Inst. for Nuclear Technology Res. (MINT), Bangi (Malaysia)

    1999-07-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing ofprinting ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films.

  16. EB/UV curing market in Malaysia

    International Nuclear Information System (INIS)

    Khairul Zaman Dahlan; Nik Ghazali Nik Salleh; Mohd Hilmi Mahmood

    1999-01-01

    Radiation curing of coatings of wood based products is expanding and being used for curing of coatings of table tops, parquet, wood panel, furniture, curtain railing, etc. UV curing of over print varnish is still the main application of UV curing in printing industry. However, curing of printing ink has also been extended in the printing of CD and VCD in addition to other printing such as paper, magazine, label on bottles, metal-can, etc. In the electronic industry, the manufacturer of printed circuit board is still the main consumer of UV curable resins. On the other hand, low energy electron beam machine is used mainly for cross-linking of heat shrink films

  17. Curing agent for polyepoxides and epoxy resins and composites cured therewith. [preventing carbon fiber release

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D. (Inventor)

    1981-01-01

    A curing for a polyepoxide is described which contains a divalent aryl radical such as phenylene a tetravalent aryl radical such as a tetravalent benzene radical. An epoxide is cured by admixture with the curing agent. The cured epoxy product retains the usual properties of cured epoxides and, in addition, has a higher char residue after burning, on the order of 45% by weight. The higher char residue is of value in preventing release to the atmosphere of carbon fibers from carbon fiber-epoxy resin composites in the event of burning of the composite.

  18. Polymerization and curing kinetics of furan resins under conventional and microwave heating

    International Nuclear Information System (INIS)

    Lopez de Vergara, Unai; Sarrionandia, Mariasun; Gondra, Koldo; Aurrekoetxea, Jon

    2014-01-01

    Graphical abstract: - Highlights: • The furan resin structure was investigated using IR and RMN techniques. • The polymerization of furan resins was developed based on multistage kinetics. • Vyazovkin numerical analysis was found the most accurate kinetic method. • Microwave curing of furan resins was much faster than thermal curing. - Abstract: The challenge of this work is the microwave curing study of low free-furfuryl alcohol content furan resins. The chemical characterization of the furan resins has been made by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The chemical composition of the resin and its reactions with p-toluensulfonic acid are proposed, with the aim of understanding the mechanism responsible for the main reactions. The results show the presence of methyl and ether bridges between the furan rings, and the formation of ketone and conjugated structures. Furthermore, the curing kinetics of the furan resins has been characterized by differential scanning calorimetry. Different methods have been applied in order to obtain and compare the activation energy of the process. Vyazovkin numerical analysis was found the most accurate method. Finally, microwave and conventional curing processes has been compared. The analysis showed that microwave curing of furan resins was twice faster than thermal curing

  19. Polymerization and curing kinetics of furan resins under conventional and microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Lopez de Vergara, Unai, E-mail: bergara@gaiker.es [Plastics and Composites Department, Gaiker IK4 Research Centre, Parque Tecnológico, Ed. 202, 48170 Zamudio Spain (Spain); Mechanical Engineering and Industrial Manufacturing Department, Mondragón Unibertsitatea, Loramendi 4, 20500 Mondragón Spain (Spain); Sarrionandia, Mariasun [Mechanical Engineering and Industrial Manufacturing Department, Mondragón Unibertsitatea, Loramendi 4, 20500 Mondragón Spain (Spain); Gondra, Koldo [Plastics and Composites Department, Gaiker IK4 Research Centre, Parque Tecnológico, Ed. 202, 48170 Zamudio Spain (Spain); Aurrekoetxea, Jon [Mechanical Engineering and Industrial Manufacturing Department, Mondragón Unibertsitatea, Loramendi 4, 20500 Mondragón Spain (Spain)

    2014-04-01

    Graphical abstract: - Highlights: • The furan resin structure was investigated using IR and RMN techniques. • The polymerization of furan resins was developed based on multistage kinetics. • Vyazovkin numerical analysis was found the most accurate kinetic method. • Microwave curing of furan resins was much faster than thermal curing. - Abstract: The challenge of this work is the microwave curing study of low free-furfuryl alcohol content furan resins. The chemical characterization of the furan resins has been made by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The chemical composition of the resin and its reactions with p-toluensulfonic acid are proposed, with the aim of understanding the mechanism responsible for the main reactions. The results show the presence of methyl and ether bridges between the furan rings, and the formation of ketone and conjugated structures. Furthermore, the curing kinetics of the furan resins has been characterized by differential scanning calorimetry. Different methods have been applied in order to obtain and compare the activation energy of the process. Vyazovkin numerical analysis was found the most accurate method. Finally, microwave and conventional curing processes has been compared. The analysis showed that microwave curing of furan resins was twice faster than thermal curing.

  20. Lipolysis, lipid peroxidation, and color characteristics of Serrano Hams from Duroc and large white pigs during dry-curing.

    Science.gov (United States)

    del Olmo, Ana; Calzada, Javier; Nuñez, Manuel

    2013-11-01

    Lipolysis, lipid peroxidation, and colorimetric characteristics of Serrano hams from Duroc and Large White pigs along a 15-mo curing period were investigated. Physicochemical parameters of both types of hams evolved similarly during curing. Twelve of 13 free fatty acids (FFAs) increased during curing, eicosatrienoic acid being the only exception. Linoleic, stearic, and arachidonic acids and the minor heptadecanoic acid reached lower concentrations, and the rest of minor FFAs higher concentrations, in Duroc hams than in Large White hams. The index measuring the early stage of lipid peroxidation declined from month 5 onwards, indicating that the phenomenon had been completed by month 5, while the index of the secondary stage of lipid peroxidation increased with curing time. Higher values were found for the 1st index in Duroc hams. Curing affected color parameters. Lightness decreased and redness increased in both types of hams, while yellowness decreased only in Duroc hams. Lower redness values were found for Duroc hams. Major differences in color parameters were found between muscles. Principal components analysis of FFAs yielded 2 main principal components. The 1st factor, correlated with all FFAs excepting eicosatrienoic acid, allowed discrimination between curing times. The 2nd factor, correlated with eicosatrienoic acid, permitted discrimination between breeds. © 2013 Institute of Food Technologists®

  1. Preparation of unsaturated acrylic prepolymer and electron beam curing of its mixture with vinyl monomers

    International Nuclear Information System (INIS)

    Pyun, H.C.; Park, W.B.; Kim, K.Y.; Sung, K.Y.

    1980-01-01

    Electron beam curable prepolymers were prepared by the addition reaction of methyl methacrylate-glycidyl methacrylate copolymer with methacrylic acid, and electron beam curing was studied for the prepolymer and their mixtures of several kind of vinyl monomers. When the reaction was carried out in the presence of triethylbenzyl ammonium chloride in N,N-dimethyl formamide solution, the rate of addition reaction obeyed first-order kinetics. In the electron beam curing, the rate of gel formation of the prepolymer was slower than that of the mixtures of prepolymer and monomers. In the curing of mixtures of prepolymer with polyethyleneglycol dimethacrylates, the rate of gel formation increased with the increase in the degree of polymerization of polyethylene oxide fraction of polyethyleneglycol dimethacrylate, and decreased with the increase the polyethyleneglycol dimethacrylate content. The properties of cured coatings were also examined. (author)

  2. Effect of Fermented Spinach as Sources of Pre-Converted Nitrite on Color Development of Cured Pork Loin

    Science.gov (United States)

    Hwang, Ko-Eun

    2017-01-01

    The effect of fermented spinach extracts on color development in cured meats was investigated in this study. The pH values of raw cured meats without addition of fermented spinach extract or nitrite (negative control) were higher (pmeats in treatment groups were decreased with increasing addition levels of fermented spinach extract. The lightness and yellowness values of raw cured meats formulated with fermented spinach extract were higher (pmeats were increased with increasing fermented spinach extract levels, whereas the yellowness values of cooked cured meats were decreased with increasing levels of fermented spinach extract. The lowest volatile basic nitrogen (VBN) and thiobarbituric acid reactive substances (TBARS) values were observed in the positive control group with addition of nitrite. TBARS values of cured meats added with fermented spinach extract were decreased with increasing levels of fermented spinach extract and VBN values of curing meat with 30% fermented spinach extract was lower than the other treatments. Total viable bacterial counts in cured meats added with fermented spinach extract ranged from 0.34-1.01 Log CFU/g. E. coli and coliform bacteria were not observed in any of the cured meats treated with fermented spinach extracts or nitrite. Residual nitrite contents in treatment groups were increased with increasing levels of fermented spinach extract added. These results demonstrated that fermented spinach could be added to meat products to improve own curing characteristics. PMID:28316477

  3. Cure and mechanical properties of carboxylated nitrile rubber (XNBR) vulcanized by alkaline earth metal compounds

    Science.gov (United States)

    Tulyapitak, Tulyapong

    Compounds of carboxylated nitrile rubber (XNBR) with alkaline metal oxides and hydroxide were prepared, and their cure and mechanical properties were investigated. Magnesium oxide (MgO) with different specific surface areas (45, 65, and 140 m2/g) was used. Increased specific surface area and concentration of MgO resulted in higher cure rate. Optimum stiffness, tensile strength, and ultimate strain required an equimolar amount of acidity and MgO. The effect of specific surface area on tensile properties was not significant. Crosslink density of XNBR-MgO vulcanizates increased with increased amounts of MgO. ATR-IR spectroscopy showed that neutralization occurs in two steps: (1) During mixing and storage, MgO reacts with carboxyl groups (RCOOH) to give RCOOMgOH. (2) Upon curing, these react bimolecularly to form RCOOMgOOCR and Mg(OH)2. Dynamic mechanical thermal analysis revealed an ionic transition at higher temperature, in addition to the glass transition. The ionic transition shifts to higher temperature with increasing MgO concentration. Like MgO-XNBR systems, cure rates of XNBR-calcium hydroxide (Ca(OH)2) and XNBR-barium oxide (BaO) compounds increased with increased content of curing agents. Curing by these two agents resulted in ionic crosslinks. To ensure optimum tensile properties, equimolar amounts of carboxyl groups and curing agents were required. Dynamic mechanical analysis revealed the ionic transition in these two systems. It shifted to higher temperature with increased amounts of curing agents. In contrast to MgO, Ca(OH)2, and BaO, calcium oxide (CaO) gave results similar to those for thermally cured samples. No ionic transition was observed in XNBR-CaO systems. Tensile strength of XNBR depended on the strength of ionic crosslinks, which was dependent on the size of the alkaline metal ions.

  4. Overview of UV and EB curing

    International Nuclear Information System (INIS)

    Garnett, J.L.

    2000-01-01

    Full text: UV and EB are complementary techniques in radiation curing. In the proposed paper, a brief review of both fields will be given. This will include principles of the process, the chemistry of the systems including monomers/oligomers/polymers used, additives required where necessary such as photoinitiators for UV, flow aids, adhesion promoters and the like. The types of equipment used in such processes will also be discussed including low energy electron beam utilisation and excimer curing. The advantages and disadvantages of both techniques will be examined. Mechanistic aspects of both curing systems will be discussed. Applications of the technology including developments in the banknote printing field will be summarised

  5. Radiation curing - twenty five years on

    International Nuclear Information System (INIS)

    Garnett, J.L.

    1995-01-01

    Progress in UV/EB curing during the past twenty five years is briefly reviewed. During this time developments in unique polymer chemistry, novel equipment design and the introduction of relevant educational programmes has enabled radiation curing to become an established technology with specific strengths in certain industries. Possible reasons for the emergence of the technology in these niche markets are discussed. Despite the worldwide recession, radiation curing is shown to be expanding at 5% per annum with the prospect of higher growth with improving economic conditions. (Author)

  6. [Mineral water as a cure].

    Science.gov (United States)

    Nocco, Priska Binz

    2008-01-01

    The treatment of diseases with mineral spring water belongs to the oldest medical therapies. The "remedy" mineral water is therefore of importance also within the pharmacy. The present pharmacy historical work examines the impact of the use of mineral waters, as well as of their dried components, as therapeutic agents in the 19th and early 20th centuries, i.e. from approx. 1810 to 1930, as well as the contributions given by pharmacists in the development and analysis of mineral water springs. Beside these aspects, the aim here is also to describe the role played by pharmacists in the production of artificial mineral water as well as in the sale and wholesale of natural and artificial mineral water. In the first part of this work the situation in Switzerland and its surrounding countries, such as Germany, France, Italy and Austria, is discussed. The second part contains a case-study of the particular situation in the Canton Tessin. It is known from the scientific literature published at that time that information on mineral water was frequently reported. Starting from the beginning of the 19th century the number of such publications increased tremendously. The major part of them were publications in scientific journals or contributions to medical and pharmaceutical manuals and reference books. In particular the spa-related literature, such as spa-guides, was of growing interest to a broad public. The inclusion of monographs into the Swiss, the Cantonal as well the foreign pharmacopoeias granted a legal frame for the mineral waters and their dried components. These works are of major importance from a pharmacy historical standpoint and represent a unique proof of historical evidence of the old medicinal drug heritage. The most frequently used therapies based on mineral waters were drinking and bath cures. Several diseases, particularly those of a chronic character, were treated with mineral waters. The positive influence of these cures on the recovery of the patients

  7. Accelerated production of dry cured hams.

    Science.gov (United States)

    Marriott, N G; Graham, P P; Shaffer, C K; Phelps, S K

    1987-01-01

    Ten uncured legs from the right side of the sampled pork carcasses (Study A) were vacuum tumbled with the cure adjuncts for 30 min (T) and 10 counterparts from the left side were tumbled 30 min, rested 30 min and tumbled an additional 30 min (TRT). Evaluations were conducted at 40 and 70 days after cure application for color, taste attributes, percentage moisture, percentage salt and NO(3)(-) and NO(2)(-) content. Study B was the same except that 18 legs were boned, tumbled and cured for 40, 56 and 70 days. The TRT samples (Study A) at 40 days sustained less color fading (P 0.05) existed among the uncooked hams. Increased cure time enhanced moisture loss and salt content (Study A) and color retention during cookery (Study B). The TRT samples had increased moisture loss and salt content (Study A). Copyright © 1987. Published by Elsevier Ltd.

  8. Financing cures in the United States.

    Science.gov (United States)

    Basu, Anirban

    2015-02-01

    True cures in health care are rare but likely not for long. The high price tag that accompanies a cure along with its rapid uptake create challenges in the financing of cures by public and private payers. In the US, the disaggregated nature of health insurance system adds to this challenge as patients frequently churn across multiple health plans. This creates a 'free-rider' problem, where no one health plan has the incentive to invest in cure since the returns will be scattered over many health plans. Here, a new health currency is proposed as a generalized version of a social impact bond that has the potential to solve this free-rider problem, as it can be traded not only between public and private payers but also within the private sector. An ensuing debate as to whether and how to develop such a currency can serve the US health care system well.

  9. NONA Cure of Prepreg Structures, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — CRG's no-oven, no-autoclave (NONA) cure of OoA or autoclave prepreg materials allows the manufacture of large composite structures without the expensive and...

  10. Radtech Asia'95 radiation curing conference proceedings

    International Nuclear Information System (INIS)

    1995-01-01

    The Radtech Asia'95 Radiation Curing Conference was held in November, 20-24, 1995 in Guilin, China. The subjects include chemistry, application, Measurement and Equipment, and Material modification. Out of 86 titles, some 30 papers are in INIS scope

  11. Is There a Cure for Cushing's Syndrome?

    Science.gov (United States)

    ... Pinterest Email Print Is there a cure for Cushing syndrome? Untreated Cushing syndrome can be life-threatening—fortunately, most people with ... their previous strength. People who no longer have Cushing syndrome might be more likely to develop diabetes, high ...

  12. Effect of cure cycle on curing process and hardness for epoxy resin

    Directory of Open Access Journals (Sweden)

    2009-09-01

    Full Text Available A 3-dimensional finite element model is developed to simulate and analyze the temperature and degree of cure field of epoxy casting part during cure process. The present model based on general finite element software ABAQUS is verified by literature example and experimental data. The numerical results show good agreement with literature example and measured data, and are even more accurate than the simulation of literature. After modeling successfully, the influence of temperature cure cycle ramps have on the temperature and degree of cure gradient is investigated. Moreover, the effect of non-uniform temperature and degree of cure field within epoxy casting part on hardness is demonstrated. The present model provides an accurate and novel method that allows further insight into the process of cure for epoxy resin.

  13. EVALUATION OF DIELECTRIC CURING MONITORING INVESTIGATING LIGHT-CURING DENTAL FILLING COMPOSITES

    Directory of Open Access Journals (Sweden)

    Johannes Steinhaus

    2011-05-01

    Full Text Available The aim of this study is the evaluation of a dielectric analysis (DEA method monitoring the curing behaviour of a light curing dental filling material in real-time. The evaluation is to extract the influence of light intensity on the photo-curing process of dental composite filling materials. The intensity change is obtained by measuring the curing process at different sample depth. It could be shown that increasing sample thickness, and therefore exponentially decreasing light intensity, causes a proportional decrease in the initial curing rate. Nevertheless, the results give rise to the assumption that lower illumination intensities over a long period cause higher overall conversion, and thus better mechanical properties. This would allow for predictions of the impact of different curing-rates on the final mechanical properties.

  14. Year of progress for radiation curing

    International Nuclear Information System (INIS)

    Mesrobian, R.B.

    1975-01-01

    New developments in ultraviolet and electron beam curing of inks and coatings are reviewed. Current installations of radiation systems are noted. An assessment is presented on raw and intermediate materials availability. Current outlook on such problems as toxicity (FDA and OSHA), residual volatiles, materials cost, adhesion and flow-out of coatings is discussed. The future potential for radiation curing systems is contrasted with that of other systems, in view of EPA requirements

  15. Radiation cured coatings for high performance products

    International Nuclear Information System (INIS)

    Parkins, J.C.; Teesdale, D.H.

    1984-01-01

    Development over the past ten years of radiation curable coating and lacquer systems and the means of curing them has led to new products in the packaging, flooring, furniture and other industries. Solventless lacquer systems formulated with acrylates and other resins enable high levels of durability, scuff resistance and gloss to be achieved. Ultra violet and electron beam radiation curing are used, the choice depending on the nature of the coating, the product and the scale of the operation. (author)

  16. Cycloaliphatic epoxide resins for cationic UV - cure

    International Nuclear Information System (INIS)

    Verschueren, K.; Balwant Kaur

    1999-01-01

    This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

  17. Gamma and electron beam curing of polymers and composites

    International Nuclear Information System (INIS)

    Saunders, C.B.; Dickson, L.W.; Singh, A.

    1987-01-01

    Radiation polymerization has helped us understand polymer chemistry, and is also playing an increasing role in the field of practical applications. Radiation curing has a present market share of about 5% of the total market for curing of polymers and composites and the annual growth rate of the radiation curing market is ≥20% per year. Advantages of radiation curing over thermal or chemical curing methods include: improved control of the curing rate, reduced curing times, curing at ambient temperatures, curing without the need for chemical initiators, and complete (100%) curing with minimal toxic chemical emissions. Radiation treatment may also be used to effect crosslinking and grafting of polymer and composite materials. The major advantage in these cases is the ability to process products in their final shape. Cable insulation, automotive and aircraft components, and improved construction materials are some of the current and near-future industrial applications of radiation curing and crosslinking. 19 refs

  18. Grafting amino drugs to poly(styrene-alt-maleic anhydride) as a potential method for drug release

    Energy Technology Data Exchange (ETDEWEB)

    Khazaei, Ardeshir; Saednia, Shahnaz; Saien, Javad; Abbasi, Fatemeh, E-mail: Khazaei_1326@yahoo.com, E-mail: ssaednia@gmail.com [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Kazem-Rostami, Masoud [Young Researchers Club and Elite, Takestan Branch, Islamic Azad University, Takestan (Iran, Islamic Republic of); Sadeghpour, Mahdieh [Department of Chemistry, Takestan Branch, Islamic Azad University, Takestan (Iran, Islamic Republic of); Borazjani, Maryam Kiani [Faculty of Science, Department of Chemistry, Bushehr Payame Noor University (PNU), Bushehr (Iran, Islamic Republic of)

    2013-07-15

    Drug delivery systems based on polymer-drug conjugates give an improved treatment with lower toxicity or side effects and be used for the treatment of different diseases. Conjugates of biodegradable poly(styrene-alt-maleic anhydride) (PSMA), with a therapeutic agents such as amantadine hydrochloride, amlodipine, gabapentin, zonisamide and mesalamine, were afforded by the formation of the amide bonds of the amino drugs that reacted with the PSMA anhydride groups. The amounts of covalently conjugated drugs were determined by a {sup 1}H NMR spectroscopic method, and the in vitro release rate in buffer solution (pH 1.3) was studied at body temperature 37 Degree-Sign C. In kinetic studies, different dissolution models were examined to obtain drug release data and the collected data were well-fitted to the Korsmeyer-Peppas equation, revealing a dominant Fickian diffusion mechanism for drug release under the in vitro conditions. (author)

  19. Facile and Efficient Acetylation of Primary Alcohols and Phenols with Acetic Anhydride Catalyzed by Dried Sodium Bicarbonate

    Directory of Open Access Journals (Sweden)

    Fulgentius Nelson Lugemwa

    2013-12-01

    Full Text Available A variety of primary alcohols and phenols were reacted with acetic anhydride at room temperature in the presence of sodium bicarbonate to produce corresponding esters in good to excellent yields. The acetylation of 4-nitrobenzyl alcohol was also carried out using other bicarbonates and carbonates. The reaction in the presence of cesium bicarbonate and lithium carbonate gave 4-nitrobenzyl acetate in excellent yield, while in the presence of Na2CO3, K2CO3, Cs2CO3, or KHCO3 the yield was in the range of 80%–95%. Calcium carbonate and cobaltous carbonate did not promote the acetylation of 4-ntirobenzyl alcohol using acetic anhydride. The acetylation of 4-nitrobenzyl alcohol was carried out using ethyl acetate, THF, toluene, diethyl ether, dichloromethane and acetonitrile, and gave good yields ranging from 75%–99%. Toluene was the best solvent for the reaction, while diethyl ether was the poorest.

  20. Thermal Aging Behaviors of Rubber Vulcanizates Cured with Single and Binary Cure Systems

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sung Seen; Ha, Sung Ho [Sejong University, Seoul (Korea, Republic of); Woo, Chang Su [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2006-03-15

    In general, an accelerated sulfur cure system consists of elemental sulfur, one or two cure accelerators, and cure activators. Crosslink density of a rubber vulcanizate determines the physical properties. By increasing the crosslink density, the modulus, hardness, resilience, and abrasion resistance increase, whereas the elongation at break, heat build-up, and stress relaxation decrease. Sulfur linkages are composed of monosulfide, disulfide, and polysulfides. Sulfur linkages, especially polysulfides, are dissociated by heating and this brings about decrease of the crosslink density.

  1. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlicek, Robert, F., Jr; Sargent, Robert

    2012-05-14

    UV curing is a green technology that is largely underutilized because UV radiation sources like Hg Lamps are unreliable and difficult to use. High Power UV LEDs are now efficient enough to replace Hg Lamps, and offer significantly improved performance relative to Hg Lamps. In this study, a modular, scalable high power UV LED curing system was designed and tested, performing well in industrial coating evaluations. In order to achieve mechanical form factors similar to commercial Hg Lamp systems, a new patent pending design was employed enabling high irradiance at long working distances. While high power UV LEDs are currently only available at longer UVA wavelengths, rapid progress on UVC LEDs and the development of new formulations designed specifically for use with UV LED sources will converge to drive more rapid adoption of UV curing technology. An assessment of the environmental impact of replacing Hg Lamp systems with UV LED systems was performed. Since UV curing is used in only a small portion of the industrial printing, painting and coating markets, the ease of use of UV LED systems should increase the use of UV curing technology. Even a small penetration of the significant number of industrial applications still using oven curing and drying will lead to significant reductions in energy consumption and reductions in the emission of green house gases and solvent emissions.

  2. Cure Cycle Optimization of Rapidly Cured Out-Of-Autoclave Composites

    Science.gov (United States)

    Dong, Anqi; Zhao, Yan; Zhao, Xinqing; Yu, Qiyong

    2018-01-01

    Out-of-autoclave prepreg typically needs a long cure cycle to guarantee good properties as the result of low processing pressure applied. It is essential to reduce the manufacturing time, achieve real cost reduction, and take full advantage of out-of-autoclave process. The focus of this paper is to reduce the cure cycle time and production cost while maintaining high laminate quality. A rapidly cured out-of-autoclave resin and relative prepreg were independently developed. To determine a suitable rapid cure procedure for the developed prepreg, the effect of heating rate, initial cure temperature, dwelling time, and post-cure time on the final laminate quality were evaluated and the factors were then optimized. As a result, a rapid cure procedure was determined. The results showed that the resin infiltration could be completed at the end of the initial cure stage and no obvious void could be seen in the laminate at this time. The laminate could achieve good internal quality using the optimized cure procedure. The mechanical test results showed that the laminates had a fiber volume fraction of 59–60% with a final glass transition temperature of 205 °C and excellent mechanical strength especially the flexural properties. PMID:29534048

  3. Effect of curing conditions on the dimensional and thermal stability of calcium phosphate cement for elevated temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Johan [Vrije Universiteit Brussel, Department of Mechanics of Materials and Constructions, Pleinlaan 2, Brussels 1050 (Belgium); Rahier, Hubert [Vrije Universiteit Brussel, Research Group of Physical Chemistry and Polymer Sciences, Pleinlaan 2, Brussels 1050 (Belgium); Wastiels, Jan, E-mail: Jan.Wastiels@vub.ac.be [Vrije Universiteit Brussel, Department of Mechanics of Materials and Constructions, Pleinlaan 2, Brussels 1050 (Belgium)

    2014-12-15

    Calcium phosphate cements (CPCs) are attractive materials for elevated temperature applications, like moulds to process thermoplastics up to 300 °C. The CPC resulting from the reaction of wollastonite with phosphoric acid cured at room temperature however contains hydrated phases like brushite, and is thus not stable when exposed to temperatures above 200 °C. A non-contact method based on digital image correlation demonstrated that isothermal curing at 60 °C reduces the thermal shrinkage up to 300 °C by 25%. This curing method results in the direct formation of the more stable monetite in a shorter curing time. The correlated results of TGA, pH of the filtration water, and DSC analysis on partially cured material indicate this. XRD diffractograms and SEM images in combination with EDX show the evolution of the transformation of wollastonite into monetite, and the structure and morphology of the formed material.

  4. Samarium-modified vanadium phosphate catalyst for the selective oxidation of n-butane to maleic anhydride

    International Nuclear Information System (INIS)

    Wu, Hua-Yi; Wang, Hai-Bo; Liu, Xin-Hua; Li, Jian-Hui; Yang, Mei-Hua; Huang, Chuan-Jing; Weng, Wei-Zheng; Wan, Hui-Lin

    2015-01-01

    Graphical abstract: The addition of a small amount of Sm into VPO catalyst brought about great changes in its physicochemical properties such as surface area, surface morphology, phase composition and redox property, thus leading to a higher catalytic performance in the selective oxidation of n-butane to maleic anhydride, as compared to the undoped VPO catalyst. - Highlights: • The addition of Sm leads to great changes in the structure of VPO catalyst. • Sm improves performance of VPO for oxidation of n-butane to maleic anhydride. • Catalytic performance is closely related to structure of VPO catalyst. - Abstract: A series of samarium-modified vanadium phosphate catalysts were prepared and studied in selective oxidation of n-butane to maleic anhydride. The catalytic evaluation showed that Sm modification significantly increased the overall n-butane conversion and intrinsic activity. N 2 -adsorption, XRD, SEM, Raman, XPS, EPR and H 2 -TPR techniques were used to investigate the intrinsic difference among these catalysts. The results revealed that the addition of Sm to VPO catalyst can increase the surface area of the catalyst, lead to a significant change in catalyst morphology from plate-like structure into rosette-shape clusters, and largely promote the formation of (VO) 2 P 2 O 7 . All of these were related to the different catalytic performance of Sm-doped and undoped VPO catalysts. The roles of the different VOPO 4 phases and the influence of Sm were also described and discussed

  5. A maleic anhydride grafted sugarcane bagasse adsorbent and its performance on the removal of methylene blue from related wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Mingliang; Du, Mingyi; Zheng, Luoyun [Key Laboratory of Polymer Processing Engineering of Ministry of Education, National Engineering Research Center of Novel Equipment for Polymer Processing, School of Mechanical & Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Wang, Bingying; Zhou, Xiangyang [College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225 (China); Jia, Zhixin [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Hu, Guoqing [Key Laboratory of Polymer Processing Engineering of Ministry of Education, National Engineering Research Center of Novel Equipment for Polymer Processing, School of Mechanical & Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Jahangir Alam, S.M., E-mail: mejahangir@scut.edu.cn [Key Laboratory of Polymer Processing Engineering of Ministry of Education, National Engineering Research Center of Novel Equipment for Polymer Processing, School of Mechanical & Automotive Engineering, South China University of Technology, Guangzhou 510640 (China)

    2017-05-01

    Sugarcane bagasse (SCB) was selected as the supporting material for grafting maleic anhydride (MA) to obtain sugarcane-bagasse-grafting-maleic-anhydride (SCB-g-MA), which was used as an adsorbent for the removal of methylene blue (MB) in the dye-containing wastewater. The granular morphology and functional groups of the material were characterized by the scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR), and solid-state analysis (13C NMR) methods. The effect(s) of the adsorbent dosage, adsorption time, initial concentration of MB, and the pH of solution on the MB adsorption performance of the material have been also investigated. The results showed that the adsorption capacity and removal rate of MB were found to be 82 mg/g and 98%, respectively. It has also showed that the adsorption behavior on the MB could be well described by the pseudo-second-order model integrated with Langmuir model. - Highlights: • Using solid phase grafting method to graft the maleic anhydride (MA) onto the Sugarcane bagasse (SCB) and get the SCB-g-MA. • SEM, FTIR and 13C NMR analysis were used to characterize the grafting of MA on to the SCB by the solid phase grafting method. • The adsorption capacity and removal rate of MB were to be 82 mg/g and 98% respectively, to show an excellent adsorption effect. • Pseudo-second-order model and Langmuir model are better fitted the adsorption kinetics and isotherms in this research.

  6. Fabrication of Poly(styrene-co-maleic anhydride)@Ag Spheres with High Surface Charge Intensity and their Self-Assembly into Photonic Crystal Films.

    Science.gov (United States)

    Bi, Jiajie; Fan, Genrui; Wu, Suli; Su, Xin; Xia, Hongbo; Zhang, Shu-Fen

    2017-10-01

    Herein, we developed a method to prepare monodisperse poly(styrene-co-maleic anhydride)@Ag (PSMA@Ag) core-shell microspheres with high surface charge intensity by using an in situ reduction method. In this method, ethylenediamine tetraacetic acid tetrasodium salt (Na 4 EDTA) was used as a reducing agent to promote the growth of Ag, and at the same time endowed the PSMA@Ag spheres with a surface charge. The monodispersity of PSMA and PSMA@Ag and the ordered array of the photonic crystal films were characterized by using SEM. The formation of Ag nanoparticles was confirmed by using TEM, HR-TEM, and XRD characterizations. Due to the existence of surface charges, the obtained PSMA@Ag microspheres easily self-assembled to form photonic crystal structures. In addition, the surface-enhanced Raman scattering (SERS) activity of the PSMA@Ag photonic crystal films was evaluated by detecting the signal from Raman probe molecules, 4-aminothiophenol (4-ATP). The PSMA@Ag photonic crystal films exhibited a high SERS effect, a low detection limit of up to 10 -8 for 4-ATP, good uniformity, and reproducibility.

  7. Microwave measurements of the spectra and molecular structure for phthalic anhydride

    Science.gov (United States)

    Pejlovas, Aaron M.; Sun, Ming; Kukolich, Stephen G.

    2014-05-01

    The microwave rotational spectrum for phthalic anhydride (PhA) has been measured in the 4-14 GHz microwave region using a pulsed-beam Fourier transform (PBFT) Flygare-Balle type microwave spectrometer. Initially, the molecular structure was calculated using Gaussian 09 suite with mp2/6-311++G** basis and the calculations were used in predicting spectra for the measured isotopologues. The experimental rotational transition frequencies were measured and used to calculate the rotational and centrifugal distortion constants. The rotational constants for the normal isotopologue, four unique 13C substituted isotopologues and two 18O isotologues, were used in a least squares fit to determine nearly all structural parameters for this molecule. Since no substitutions were made at hydrogen sites, the calculated positions of the hydrogen atoms relative to the bonded carbon atoms were used in the structure determination. The rotational constants for the parent isotopologue were determined to be A = 1801.7622(9) MHz, B = 1191.71816(26) MHz, C = 717.44614(28) MHz. Small values for the centrifugal distortion constants were obtained; DJ = 0.0127 kHz, DJK = 0.0652 kHz, and DK = -0.099 kHz, indicating a fairly rigid structure. The structure of PhA is planar with a negative inertial defect of Δ = -0.154 amu Å2. Structural parameters from the mp2 and DFT calculations are in quite good agreement with measured parameters.

  8. Grafting of Maleic Anhydride onto Polyethylene by Blend Process forEnvironmentally Friendly Plastics

    International Nuclear Information System (INIS)

    Hendrana, Sunit; Retno-Yusiasih; Sudirman; Ipit-Karyaningsih; Djimat-Lisnawati

    2000-01-01

    Grafting maleic anhydride (MAH) onto polyethylene is one of the route tomake plastics which can be consumed by microbe in the soil. High temperaturesolution process is one of the method to perform grafting. This method is notreally handy since it involves many steps. Therefore, in this work a simplemethod is performed to graft MAH onto polyethylene, i.e., blending process.As the process occurs in melt, the reaction is more likely to be diffusioncontrol rather than chemical control. Therefore, there are many parameterscan affect the grafting such as temperature of the blending, speed of therotation, concentration of MAH and concentration of dicumyl peroxide (DCP).Preliminary work in our laboratorium found an optimum condition for the firsttwo parameters. Thus, in this work the effect of concentration of MAH and DCPis studied into the effectiveness of grafting process. One of the indicationof unexpected reaction is formation of gel, or in other words the formationof X-link among polyethylene molecules. The grafted polyethylene ischaracterized by calculation of gel content, thermal properties by TG/DTA andFourier Transform Infrared (FTIR). The results show the concentration of MAHand DCP play roles. However, initiator DCP has more significance effect thanthe MAH. (author)

  9. Effect of maleic anhydride treatment on the mechanical properties of sansevieria fiber/vinyl ester composites

    Science.gov (United States)

    Pradipta, Rangga; Mardiyati, Steven, Purnomo, Ikhsan

    2017-03-01

    Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as reinforcement material in polymer matrix composites. Chemical treatment on reinforcing fiber is crucial to reduce hydrophilic tendency and thus improve compatibility with the matrix. In this study, effect of maleic anhydride as chemical treatment on the mechanical properties of Sansevieria fiber/vinyl ester composite was investigated. Sansevieria fibers were immersed by using NaOH 3% for two hours at 100°C and then treated by using maleic anhydrate for two hours at 120°C. Composites were prepared by solution casting with various volume fractions of fiber; 0%, 2.5%, 5%, 7.5% and 10%. Actual density, volume fraction of void and mechanical properties of composite were conducted according to ASTM standard testing methods D792, D3171 and D3039. It was found that mechanical properties of composites increased as volume fractions of fiber was increased. The highest tensile strength and modulus of elasticity of composites were 57.45 MPa and 3.47 GPa respectively, obtained from composites with volume fraction of fiber 10%.

  10. Improved removal of malachite green from aqueous solution using chemically modified cellulose by anhydride.

    Science.gov (United States)

    Zhou, Yanmei; Min, Yinghao; Qiao, Han; Huang, Qi; Wang, Enze; Ma, Tongsen

    2015-03-01

    Cellulose modified with maleic (M) and phthalic (P) anhydride, to be named CMA and CPA, were tested as feasible adsorbents for the removal of malachite green from aqueous solution. At the same time, the uptake ability of natural cellulose was also studied for comparison. The structure of material was characterized by FT-IR and XRD. The effects of solution pH, initial dye concentration, contact time and temperature were investigated in detail by batch adsorption experiments. The kinetic and isotherm studies suggested that the adsorption followed the pseudo-second-order model and Langmuir isotherm. The maximum adsorption capacity on CMA and CPA were 370 mg g(-1) and 111 mg g(-1), respectively. Furthermore, the thermodynamics studies indicated the spontaneous nature of adsorption of malachite green on adsorbents. All the studied results showed that the modified cellulose could be used as effective adsorption material for the removal of malachite green from aqueous solutions. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The use of chemical modified chitosan with succinic anhydride in the methylene blue adsorption

    International Nuclear Information System (INIS)

    Lima, Ilauro S.; Ribeiro, Emerson S.; Airoldi, Claudio

    2006-01-01

    The adsorption capacity of a-chitosan and its modified form with succinic anhydride was compared with the traditional adsorbent active carbon by using the dye methylene blue, employed in the textile industry. The isotherms for both biopolymers were classified as SSA systems in the Giles model, more specifically in L class and subgroup 3. The dye concentration in the supernatant in the adsorption assay was determined through electronic spectroscopy. By calorimetric titration thermodynamic data of the interaction between methylene blue and the chemically modified chitosan at the solid/liquid interface were obtained. The enthalpy of the dye/chitosan interaction gave 2.47 ± 0.02 kJ mol-1 with an equilibrium constant of 7350 ± 10 and for the carbon/dye interaction this constant gave 5951 ± 8. The spontaneity of these adsorptions are reflected by the free Gibbs energies of -22.1 ± 0.4 and -21.5 ± 0.2 kJ mol-1, respectively, found for these systems. This new adsorbent derived from a natural polysaccharide is as efficient as activated carbon. However 97% of the bonded dye can be eluted by sodium chloride solution, while this same operation elutes only 42% from carbon. Chitosan is efficient in dye removal with the additional advantage of being cheap, non-toxic, biocompatible and biodegradable. (author)

  12. Preparation And Physicochemical Properties of Octenyl Succinic Anhydride (OSA) Modified Sago Starch

    International Nuclear Information System (INIS)

    Nur Farhana Zainal Abiddin; Anida Yusoff; Noorlaila Ahmad

    2016-01-01

    Starch from sago (Metroxylon sagu) was esterified with octenyl succinic anhydride (OSA) in order to regulate its shortcoming by adding amphiphilic properties. The objective of this work is to determine the physicochemical properties of native sago and OSA sago starches. The OSA sago starch was produced according to the optimum condition generated via response surface methodology (RSM) with 5.00 % OSA at pH 7.20 and a reaction time of 9.65 hours. The esterified sago starch gives a degree of substitution (DS) value of 0.012. The physicochemical properties of OSA sago starch was determined by measuring the amylose content, laser diffraction particle size analyzer, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The amylose content for OSA sago starch was found to be reduced after esterification reaction. The particle size of OSA sago starch was found to increase significantly (p<0.05) compared to their native starches. Scanning electron microscopy (SEM) revealed that OSA starch developed slightly rough surface and their edges lost some definition. FT-IR spectroscopy shows that there was appearance of new absorption correspond to ester carbonyl group (1717 cm -1 ) and carboxylate RCOO- (1569 cm -1 ). This study showed that the physicochemical properties of modified starches were influenced not only by DS but also on the botanical origin of the starches. (author)

  13. Four-year evaluation of workers exposed to trimellitic anhydride. A brief report

    International Nuclear Information System (INIS)

    McGrath, K.G.; Roach, D.; Zeiss, C.R.; Patterson, R.

    1984-01-01

    In a four-year clinical, immunologic, and environmental study of trimellitic anhydride (TMA) exposure in a single plant, 20 workers exposed to TMA powder were evaluated in 1979 and a total of 32 workers were evaluated from 1979 to 1983. Two distinct groups emerged before and after workplace control improvements were made in 1979. Seventeen of the original 20 workers were available for longitudinal study through 1983. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to 125I TM-HSA (human serum albumin) were performed on all 32 workers. In 1979, six workers had antibody against TM-HSA, three had the late respiratory systemic syndrome, and two had TMA-induced allergic rhinitis or allergic rhinitis and asthma. One worker had antibody against TM-HSA without illness. Fifteen additional workers were evaluated longitudinally after institution of several workplace control measures. Four of these 15 workers had TMA exposure prior to environmental improvement and joined the study in 1982. The remaining 11 workers joined the study in 1982 and had at least two years of TMA exposure in the modified workplace. None of these 11 workers developed a TMA-induced immunologic syndrome or significant total or specific IgE antibody binding to 125I TM-HSA

  14. Morphology, rheology and electrical resistivity of PLLA/HDPE/CNT nanocomposites: Effect of maleic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Li-na; Chen, Jie; Dai, Jian; Chen, Hai-ming; Yang, Jing-hui [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Yong, E-mail: yongwang1976@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, Chao-liang [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China)

    2015-02-15

    As a part of serial work about tuning the selective location of carbon nanotubes (CNTs) in immiscible polymer blends, this work reports the effects of component polarity and viscosity ratio between components on the selective location of CNTs and the resultant electrical resistivity of the nanocomposites. To achieve the research aim, maleic anhydride (MA) was grafted onto poly(L-lactide) (PLLA) main chain through a reactive compounding processing. After that, different contents of CNTs were incorporated into blends of high density polyethylene (HDPE) and PLLA (or PLLA-g-MA). The morphologies of the ternary nanocomposites and the selective location of CNTs in the nanocomposites were characterized using scanning electron microscope (SEM) and transmission electron microscope (TEM). The microstructure of nanocomposites and the dispersion of CNTs were further proved by rheological measurement. Finally, the electrical resistivity of nanocomposites containing different CNT contents was measured. The results showed that through increasing the polarity of PLLA and decreasing the melt viscosity, CNTs were kinetically trapped at the blend interface region. Consequently, largely decreased percolation threshold was achieved for the PLLA-g-MA/HDPE/CNT nanocomposites. The morphological changes as well as the rheological properties were also comparatively analyzed. - Highlights: • PLLA/HDPE/CNT and PLLA-g-MA/HDPE/CNT composites were prepared. • Different selective location states of CNTs were achieved in different composites. • Selectively located CNTs at the interface resulted in lower percolation threshold.

  15. Effect of surface modified kaolin on properties of polypropylene grafted maleic anhydride

    Science.gov (United States)

    Yang, Ni; Zhang, Zuo-Cai; Ma, Ning; Liu, Huan-Li; Zhan, Xue-Qing; Li, Bing; Gao, Wei; Tsai, Fang-Chang; Jiang, Tao; Chang, Chang-Jung; Chiang, Tai-Chin; Shi, Dean

    To achieve reinforcement of mechanical and thermal performances of polypropylene (PP) product, this work aimed at fabrication of surface modified kaolin (M-kaolin) filled polypropylene grafted maleic anhydride (PP-g-MAH) composites with varying contents of fillers and investigation of their mechanical and thermal properties. And the prepared PP-g-MAH/M-kaolin composites were characterized by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Fracture analysis by SEM showed M-kaolin particles were well dispersed in the PP-g-MAH matrix. Mechanical behaviors were determined by tensile strength, tensile strain at break and impact strength analysis. Impact strength of PP-g-MAH/2 wt% M-kaolin composites was improved up to 30% comparing with unfilled composites. Thermostability had been found enhanced when M-kaolin added. The results revealed PP-g-MAH/M-kaolin composites showed the optimal thermal and mechanical properties when 2 wt% of M-kaolin was added.

  16. Bond strength of orthodontic light-cured resin-modified glass ionomer cement.

    Science.gov (United States)

    Cheng, Hsiang Yu; Chen, Chien Hsiu; Li, Chuan Li; Tsai, Hung Huey; Chou, Ta Hsiung; Wang, Wei Nan

    2011-04-01

    The purpose of this study was to compare the bond strengths and debonded interfaces achieved with light-cured resin-modified glass ionomer cement (RMGIC) and conventional light-cured composite resin. In addition, the effects of acid etching and water contamination were examined. One hundred human premolars were randomly divided into five equal groups. The mini Dyna-lock upper premolar bracket was selected for testing. The first four groups were treated with light-cured RMGIC with or without 15 per cent phosphoric acid-etching treatment and with or without water contamination preceding bracket bonding. The control samples were treated with the conventional light-cured Transbond composite resin under acid etching and without water contamination. Subsequently, the brackets were debonded by tensile force using an Instron machine. The modified adhesive remnant index (ARI) scores were assigned to the bracket base of the debonded interfaces using a scanning electron microscope. The bond strength and modified ARI scores were determined and analysed statistically by one-way analysis of variance and chi-square test. Under all four conditions, the bond strength of the light-cure RMGIC was equal to or higher than that of the conventional composite resin. The highest bond strength was achieved when using RMGIC with acid etching but without water contamination. The modified ARI scores were 2 for Fuji Ortho LC and 3 for Transbond. No enamel detachment was found in any group. Fifteen per cent phosphoric acid etching without moistening the enamel of Fuji Ortho LC provided the more favourable bond strength. Enamel surfaces, with or without water contamination and with or without acid etching, had the same or a greater bond strength than Transbond.

  17. Cure kinetics and mechanical interfacial characteristics of zeolite/DGEBA composites

    International Nuclear Information System (INIS)

    Park, Soo Jin; Kim, Young Mi; Shin, Jae Sup

    2003-01-01

    In this work, the zeolite/diglycidylether of bisphenol A(DGEBA) systems were investigated in terms of the cure kinetics and mechanical interfacial properties of the composites. The 4, 4-Diamino Diphenyl Methane(DDM) was used as a curing agent for epoxy. Two types of zeolite(PZ) were prepared with 15 and 35 wt% KOH treatments(15-BZ and 35-BZ, respectively) for 24 h, and their surface characteristics were studied by X-ray Photoelectron Spectroscopy (XPS) and X-Ray Diffraction (XRD). Cure kinetics of the composites were examined in the context of Differential Scanning Calorimetry(DSC), and mechanical interfacial properties were investigated in critical stress intensity factor(K IC ) and critical strain energy release rate(G IC ). In the results of XPS and XRD, sodium ion(Na) of zeolite was exchanged for potassium ion(K), resulting from the treatment of KOH. Also, Si 2p /A1 2p composition ratios of the treated zeolite were increased, which could be attributed to the weakening of A1-O bond in framework. Cure activation energy(E a ) of 15-BZ composites was decreased, whereas K IC and G IC were increased, compared with those of the pure zeolite/DGEBA composites. It was probably accounted that the acidity of zeolite was increased by surface treatments and the cure reaction between zeolite and epoxy was influenced on the increased acidity of zeolite

  18. Virulence factor genotypes of Helicobacter pylori affect cure rates of eradication therapy.

    Science.gov (United States)

    Sugimoto, Mitsushige; Yamaoka, Yoshio

    2009-01-01

    The cure rates of Helicobacter pylori infection by using a combination of a proton pump inhibitor (PPI) and antimicrobial agents are mainly influenced by bacterial susceptibility to antimicrobial agents and the magnitude of acid inhibition during the treatment. Currently used empirical triple therapies do not reliably produce a > or =80% cure rate on an intention-to-treat basis. Therefore, tailored regimens based on relevant microbiological findings and pharmacogenomics are recommended for attaining an acceptable > or =95% cure rate. Recently, virulence factors of H. pylori, such as cagA and vacA, are reported to be major factors determining the cure rates. Individuals infected with strains with cagA-negative and vacA s2 genotypes have significantly increased risk of eradication failure of H. pylori infection. These virulence factors enhance gastric mucosal inflammation and are associated with the development of peptic ulcer and gastric cancer. H. pylori virulence factors induce proinflammatory cytokines, such as interleukin (IL)-1, IL-8, and tumor necrosis factor (TNF)- which influence mucosal inflammation and/or gastric acid secretion. When physicians select an H. pylori eradication regimen with an acceptable cure rate, they might need to consider H. pylori virulence factors, especially cagA and vacA.

  19. Proceedings of workshop on surface finishing by radiation curing technology: radiation curing for better finishing

    International Nuclear Information System (INIS)

    1993-01-01

    This book compiled the paper presented at this workshop. The papers discussed are 1. Introduction to radiation curing, 2. Radiation sources -ultraviolet and electron beams, 3. UV/EB curing of surface coating - wood and nonwood substrates, 4. Development of EPOLA (epoxidised palm oil products acrylate) and its application, 5. Development of radiation-curable resin based natural rubber

  20. Proceedings of workshop on surface finishing by radiation curing technology: radiation curing for better finishing

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    This book compiled the paper presented at this workshop. The papers discussed are 1. Introduction to radiation curing, 2. Radiation sources -ultraviolet and electron beams, 3. UV/EB curing of surface coating - wood and nonwood substrates, 4. Development of EPOLA (epoxidised palm oil products acrylate) and its application, 5. Development of radiation-curable resin based natural rubber.

  1. Excimer Laser Curing Of Polymer Coatings

    Science.gov (United States)

    Klick, David; Akerman, M. Alfred; Paul, George L.; Supurovic, Darko; Tsuda, Haruki

    1988-12-01

    The use of the excimer laser as a source of energy for photo-assisted curing of industrial polymeric coatings was investigated. Presently, UV lamps are sometimes used to excite a photoinitiating molecule mixed with the starting monomers and oligomers of a coating. The resulting polymeric chain reaction multiplies the effect of the initial photons, making economical use of the light source. The high cost of laser photons may thus be justifiable if lasers provide advantages over lamps. A series of visibly transparent 7 μm coatings (a typical thickness for 'slick' magazine coatings) with various photoinitiators, monomers, and oligomers was illuminated with excimer laser light of various wavelengths, fluences, and pulse repetition rates. For the optimum parameters, it was found that the laser had large advantages in curing speed over existing UV lamp processes, due to its monochromaticity. Pigmented coatings (20 μm TiO2 mixtures typical of appliance or automotive finishes) are not easily cured with UV lamps due to the inability of light to penetrate the absorbing and scattering pigmented layer. However, economically-viable cure rates were achieved with certain photoinitiators using a tunable excimer-pumped dye laser. A prototype of such a laser suitable for factory use was built and used to cure these coatings. Results are scaled to a factory situation, and costs are calculated to show the advantages of the laser method over currently used processes.

  2. Effects of feeding high protein or conventional canola meal on dry cured and conventionally cured bacon.

    Science.gov (United States)

    Little, K L; Bohrer, B M; Stein, H H; Boler, D D

    2015-05-01

    Objectives were to compare belly, bacon processing, bacon slice, and sensory characteristics from pigs fed high protein canola meal (CM-HP) or conventional canola meal (CM-CV). Soybean meal was replaced with 0 (control), 33, 66, or 100% of both types of canola meal. Left side bellies from 70 carcasses were randomly assigned to conventional or dry cure treatment and matching right side bellies were assigned the opposite treatment. Secondary objectives were to test the existence of bilateral symmetry on fresh belly characteristics and fatty acid profiles of right and left side bellies originating from the same carcass. Bellies from pigs fed CM-HP were slightly lighter and thinner than bellies from pigs fed CM-CV, yet bacon processing, bacon slice, and sensory characteristics were unaffected by dietary treatment and did not differ from the control. Furthermore, testing the existence of bilateral symmetry on fresh belly characteristics revealed that bellies originating from the right side of the carcasses were slightly (P≤0.05) wider, thicker, heavier and firmer than bellies from the left side of the carcass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Residual Stress Developed During the Cure of Thermosetting Polymers: Optimizing Cure Schedule to Minimize Stress.

    Energy Technology Data Exchange (ETDEWEB)

    Kropka, Jamie Michael; Stavig, Mark E.; Jaramillo, Rex

    2016-06-01

    When thermosetting polymers are used to bond or encapsulate electrical, mechanical or optical assemblies, residual stress, which often affects the performance and/or reliability of these devices, develops within the structure. The Thin-Disk-on-Cylinder structural response test is demonstrated as a powerful tool to design epoxy encapsulant cure schedules to reduce residual stress, even when all the details of the material evolution during cure are not explicitly known. The test's ability to (1) distinguish between cohesive and adhesive failure modes and (2) demonstrate methodologies to eliminate failure and reduce residual stress, make choices of cure schedules that optimize stress in the encapsulant unambiguous. For the 828/DEA/GMB material in the Thin-Disk-on-Cylinder geometry, the stress associated with cure is significant and outweighs that associated with cool down from the final cure temperature to room temperature (for measured lid strain, Scure I > I I e+h erma * II) * The difference between the final cure temperature and 1 1 -- the temperature at which the material gels, Tf-T ge i, was demonstrated to be a primary factor in determining the residual stress associated with cure. Increasing T f -T ge i leads to a reduction in cure stress that is described as being associated with balancing some of the 828/DEA/GMB cure shrinkage with thermal expansion. The ability to tune residual stress associated with cure by controlling T f -T ge i would be anticipated to translate to other thermosetting encapsulation materials, but the times and temperatures appropriate for a given material may vary widely.

  4. Status of radiation curing in South America

    International Nuclear Information System (INIS)

    Machado, L.D.B.; Rotta, A.C.; Petrie, I.

    2007-01-01

    In August 2006, an agreement between the Rad tech International North America and the ATBCR, the Brazillian Technical Association for Radiation cure, turns ATCBR into RadTech South America. This new institution starts with already 10 years of history and pioneering technical experience and achievements in UV and EB radiation cure. Both RadTech institutions have asserted a whole cooperation and information exchange to continue with the initial ATBCR compromise in promoting UV and EB curing technology and to make it available to professionals, enterprise and other organizations. The RadTech South America has it's headquarter at the Energy and Nuclear Research Institute, IPEN, in Sao Paulo, Brazil, from whom also gets sponsorship. (Author)

  5. Comparative study of the use of non-ionizing and ionizing radiation in the cure of epoxy resin: microwave versus electron electron

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, Daniel, E-mail: daniel.kersting@usp.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP/USP), Sao Paulo, SP (Brazil); Wiebeck, Helio, E-mail: hwiebeck@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica; Marinucci, Gerson; Silva, Leonardo G.A. e, E-mail: marinuci@ipen.br, E-mail: gasilva@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Several processes for curing epoxy resins were developed over the years. Two methods are discussed in this paper, in order to present the main advantages and disadvantages of using microwave radiation (non-ionizing radiation) and electron beam radiation (ionizing radiation). The microwave radiation is a non-ionizing radiation, with great power of penetration and transfer of heat in microwave absorbing materials, or materials with microwave absorbing fillers. The frequency usually used in research and development is 2.45 GHz, the same available in commercial equipment. The microwave effect provides increase on the collision velocity between the reactant which, combined with energy absorbed by the reaction system, accelerates the curing reaction. None modifications in the epoxy system are required to use microwave heating for the curing process.On the other hand, the electron beam is a form of ionizing radiation in which the high energy electrons have the ability to interact with the irradiated material and produce ions, free radicals, and molecules in excited state, which can be used to initiate and propagate a polymerization. Specific initiators are necessary for an effective cure of the resin. In this study, a DGEBA epoxy resin with initiators based on anhydride and amine was used under the same conditions indicated by the manufacturer. The curing of the catalyzed system was performed in a domestic microwave oven adapted for laboratory use. The degradation and glass transition temperatures were evaluated by thermal analysis techniques. For comparative purposes, it was used data available in the literature for electron beam irradiation. (author)

  6. Comparative study of the use of non-ionizing and ionizing radiation in the cure of epoxy resin: microwave versus electron electron

    International Nuclear Information System (INIS)

    Kersting, Daniel; Wiebeck, Helio

    2013-01-01

    Several processes for curing epoxy resins were developed over the years. Two methods are discussed in this paper, in order to present the main advantages and disadvantages of using microwave radiation (non-ionizing radiation) and electron beam radiation (ionizing radiation). The microwave radiation is a non-ionizing radiation, with great power of penetration and transfer of heat in microwave absorbing materials, or materials with microwave absorbing fillers. The frequency usually used in research and development is 2.45 GHz, the same available in commercial equipment. The microwave effect provides increase on the collision velocity between the reactant which, combined with energy absorbed by the reaction system, accelerates the curing reaction. None modifications in the epoxy system are required to use microwave heating for the curing process.On the other hand, the electron beam is a form of ionizing radiation in which the high energy electrons have the ability to interact with the irradiated material and produce ions, free radicals, and molecules in excited state, which can be used to initiate and propagate a polymerization. Specific initiators are necessary for an effective cure of the resin. In this study, a DGEBA epoxy resin with initiators based on anhydride and amine was used under the same conditions indicated by the manufacturer. The curing of the catalyzed system was performed in a domestic microwave oven adapted for laboratory use. The degradation and glass transition temperatures were evaluated by thermal analysis techniques. For comparative purposes, it was used data available in the literature for electron beam irradiation. (author)

  7. Tuning the conformation of synthetic co-polypeptides of serine and glutamic acid through control over polymer composition

    NARCIS (Netherlands)

    Canning, A.; Pasquazi, A.; Fijten, M.; Rajput, S.; Buttery, L.; Aylott, J.W.; Zelzer, M.

    2016-01-01

    Ring opening polymerization (ROP) of N-carboxy anhydride (NCA) amino acids presents a rapid way to synthesize high molecular weight polypeptides with different amino acid compositions. The compositional and functional versatility of polypeptides make these materials an attractive choice for

  8. Elucidation of substituted ester group position in octenylsuccinic anhydride modified sugary maize soluble starch.

    Science.gov (United States)

    Ye, Fan; Miao, Ming; Huang, Chao; Lu, Keyu; Jiang, Bo; Zhang, Tao

    2014-12-03

    The octenylsuccinic groups in esterification-modified sugary maize soluble starches with a low (0.0191) or high (0.0504) degree of substitution (DS) were investigated by amyloglucosidase hydrolysis followed by a combination of chemical and physical analysis. The results showed the zeta-potential remained at approximately the same value regardless of excessive hydrolysis. The weight-average molecular weight decreased rapidly and reached 1.22 × 10(7) and 1.60 × 10(7) g/mol after 120 min for low-DS and high-DS octenylsuccinic anhydride (OSA) modified starch, respectively. The pattern of z-average radius of gyration as well as particle size change was similar to that of Mw, and z-average radius of gyration decreased much more slowly, especially for high-DS OSA starch. Compared to native starch, two characteristic absorption peaks at 1726.76 and 1571.83 cm(-1) were observed in FT-IR spectra, and the intensity of absorption peaks increased with increasing DS. The NMR results showed that OSA starch had several additional peaks at 0.8-3.0 ppm and a shoulder at 5.56 ppm for OSA substituents, which were grafted at O-2 and O-3 positions in soluble starch. The even distribution of OSA groups in the center area of soluble starch particle has been directly shown under CLSM. Most substitutions were located near branching points of soluble starch particles for a low-DS modified starch, whereas the substituted ester groups were located near branching points as well as at the nonreducing ends in OSA starch with a high DS.

  9. Emulsion stabilizing capacity of intact starch granules modified by heat treatment or octenyl succinic anhydride.

    Science.gov (United States)

    Timgren, Anna; Rayner, Marilyn; Dejmek, Petr; Marku, Diana; Sjöö, Malin

    2013-03-01

    Starch granules are an interesting stabilizer candidate for food-grade Pickering emulsions. The stabilizing capacity of seven different intact starch granules for making oil-in-water emulsions has been the topic of this screening study. The starches were from quinoa; rice; maize; waxy varieties of rice, maize, and barley; and high-amylose maize. The starches were studied in their native state, heat treated, and modified by octenyl succinic anhydride (OSA). The effect of varying the continuous phase, both with and without salt in a phosphate buffer, was also studied. Quinoa, which had the smallest granule size, had the best capacity to stabilize oil drops, especially when the granules had been hydrophobically modified by heat treatment or by OSA. The average drop diameter (d 32) in these emulsions varied from 270 to 50 μm, where decreasing drop size and less aggregation was promoted by high starch concentration and absence of salt in the system. Of all the starch varieties studied, quinoa had the best overall emulsifying capacity, and OSA modified quinoa starch in particular. Although the size of the drops was relatively large, the drops themselves were in many instances extremely stable. In the cases where the system could stabilize droplets, even when they were so large that they were visible to the naked eye, they remained stable and the measured droplet sizes after 2 years of storage were essentially unchanged from the initial droplet size. This somewhat surprising result has been attributed to the thickness of the adsorbed starch layer providing steric stabilization. The starch particle-stabilized Pickering emulsion systems studied in this work has potential practical application such as being suitable for encapsulation of ingredients in food and pharmaceutical products.

  10. Radiation curing applications of palm oil acrylates

    International Nuclear Information System (INIS)

    Mohd Hilmi Mahmood; Khairul Zaman; Rida, Anak Tajau; Mek Zah Salleh; Rosley Che Ismail

    2007-01-01

    Various palm oil based urethan acrylate prepolymers (UP) were prepared from palm oil based polyols, diisocyanate compounds and hydroxyl terminated acrylate monomers by following procedure derived from established methods. The products were compared with each other in term of their molecular weights (MW), viscosities, curing speed by UV irradiation, gel contents and film hardness. The molecular structure of diisocyanate compounds and hydroxyl acrylate monomers were tend to determine the molecular weights and hence viscosities of the final products of urethan acrylate prepolymers (UP), whereas, the MW of the UP has no direct effects on the UV curing properties of the prepolymers. (author)

  11. Curing mechanism of flexible aqueous polymeric coatings.

    Science.gov (United States)

    Irfan, Muhammad; Ahmed, Abid Riaz; Kolter, Karl; Bodmeier, Roland; Dashevskiy, Andriy

    2017-06-01

    The objective of this study was to explain curing phenomena for pellets coated with a flexible polymeric coating based on poly(vinyl acetate) (Kollicoat® SR 30D) with regard to the effect of starter cores, thickness of drug layer, adhesion of coating to drug-layered-cores as well as coating properties. In addition, appropriate approaches to eliminate the curing effect were identified. Sugar or MCC cores were layered with the model drugs carbamazepine, theophylline, propranolol HCl, tramadol HCl and metoprolol HCl using HPMC (5 or 25% w/w, based on drug) as a binder. Drug-layered pellets were coated with Kollicoat® SR 30D in a fluidized bed coater using TEC (10% w/w) as plasticizer and talc (35-100% w/w) as anti-tacking agent. Drug release, pellet properties (morphology, water uptake-weight loss and osmolality) and adhesion of the coating to the drug layer were investigated as a function of curing at 60°C or 60°C/75% RH for 24h. The film formation of the aqueous dispersion of Kollicoat® SR 30D was complete, and therefore, a strong curing effect (decrease in drug release) at elevated temperature and humidity (60°C/75% RH) could not be explained by the well-known hydroplasticization and the further gradual coalescence of the colloidal polymer particles. According to the provided mechanistic explanation, the observed curing effect was associated with (1) high flexibility of coating, (2) adhesion between coating and drug layer, (3) water retaining properties of the drug layer, and (4) osmotically active cores. Unwanted curing effects could be minimized/eliminated by the addition of talc or/and pore-forming water soluble polymers in the coating, increasing binder amount or applying an intermediate coating, by increasing the thickness of drug layer or using non-osmotic cores. A new insight into curing phenomena mainly associated with the adhesion between drug layer and coating was provided. Appropriate approaches to avoid unwanted curing effect were identified

  12. UV/EB curing in Australia

    International Nuclear Information System (INIS)

    Woods, R.; Garnett, J.; Loo Teck Ng

    1999-01-01

    Progress in LTV/EB curing is reviewed in Australia. Generally the technology is used by those industries where curing is well developed in Europe and North America, however the scale is an order of magnitude lower due to the smaller market size. The Asian economic crisis does not appear to have affected expansion of the technology in Australia. EB continues to be successfully used in the packaging and foam fields whilst in UV, security devices, particularly banknotes are steadily expanding especially in export markets have been studied

  13. Citric Acid Production by Aspergillus niger Cultivated on Parkia biglobosa Fruit Pulp

    OpenAIRE

    Auta, Helen Shnada; Abidoye, Khadijat Toyin; Tahir, Hauwa; Ibrahim, Aliyu Dabai; Aransiola, Sesan Abiodun

    2014-01-01

    The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5-dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine-acetic anhydride methods. The studies revealed that production parameters (pH, inoculum size, substrate concentration, incubation temperature, and fermentation period) had profound effect on the amount of citric acid produced...

  14. Effect of residual ascorbate on determination of nitrite in commercial cured meat products.

    Science.gov (United States)

    Fox, J B; Doerr, R C; Gates, R

    1984-01-01

    Residual ascorbate in cured meat slurries results in different amounts of pigment being produced from different Griess reagent combinations. The phenomenon was used to study residual ascorbate in commercial cured meat products which had a variety of textures, acidities, moisture and meat content, fat, homogeneity, initial nitrite, and processing conditions. Diluting and heating the samples according to the AOAC procedure did not completely eliminate the ascorbate interference, but making the sample alkaline did. Determining nitrite separately in supernate and precipitate from the first dilution showed the effect of heating to be the elimination of interferences and solubilization or extraction of nitrite from the precipitate.

  15. Strength of Geopolymer Cement Curing at Ambient Temperature by Non-Oven Curing Approaches: An Overview

    Science.gov (United States)

    Wattanachai, Pitiwat; Suwan, Teewara

    2017-06-01

    At the present day, a concept of environmentally friendly construction materials has been intensively studying to reduce the amount of releasing greenhouse gases. Geopolymer is one of the cementitious binders which can be produced by utilising pozzolanic wastes (e.g. fly ash or furnace slag) and also receiving much more attention as a low-CO2 emission material. However, to achieve excellent mechanical properties, heat curing process is needed to apply to geopolymer cement in a range of temperature around 40 to 90°C. To consume less oven-curing energy and be more convenience in practical work, the study on geopolymer curing at ambient temperature (around 20 to 25°C) is therefore widely investigated. In this paper, a core review of factors and approaches for non-oven curing geopolymer has been summarised. The performance, in term of strength, of each non-oven curing method, is also presented and analysed. The main aim of this review paper is to gather the latest study of ambient temperature curing geopolymer and to enlarge a feasibility of non-oven curing geopolymer development. Also, to extend the directions of research work, some approaches or techniques can be combined or applied to the specific properties for in-field applications and embankment stabilization by using soil-cement column.

  16. Curing kinetics of visible light curing dental resin composites investigated by dielectric analysis (DEA).

    Science.gov (United States)

    Steinhaus, Johannes; Hausnerova, Berenika; Haenel, Thomas; Großgarten, Mandy; Möginger, Bernhard

    2014-03-01

    During the curing process of light curing dental composites the mobility of molecules and molecule segments is reduced leading to a significant increase of the viscosity as well as the ion viscosity. Thus, the kinetics of the curing behavior of 6 different composites was derived from dielectric analysis (DEA) using especially redesigned flat sensors with interdigit comb electrodes allowing for irradiation at the top side and measuring the ion viscosity at the bottom side. As the ion viscosities of dental composites change 1-3 orders of magnitude during the curing process, DEA provides a sensitive approach to evaluate their curing behavior, especially in the phase of undisturbed chain growth. In order to determine quantitative kinetic parameters a kinetic model is presented and examined for the evaluation of the ion viscosity curves. From the obtained results it is seen that DEA might be employed in the investigation of the primary curing process, the quality assurance of ingredients as well as the control of processing stability of the light curing dental composites. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Effect of Particular Breed on the Chemical Composition, Texture, Color, and Sensorial Characteristics of Dry-cured Ham

    Directory of Open Access Journals (Sweden)

    Pil Nam Seong

    2014-08-01

    Full Text Available The present study demonstrates the impact of specific breed on the characteristics of dry-cured ham. Eighty thighs from Korean native pig (KNP, crossbreed (Landrace×Yorkshire♀×Duroc♂ (LYD, Berkshire (Ber, and Duroc (Du pig breeds (n = 10 for each breed were used for processing of dry-cured ham. The thighs were salted with 6% NaCl (w/w and 100 ppm NaNO2, and total processing time was 413 days. The effects of breed on the physicochemical composition, texture, color and sensory characteristics were assessed on the biceps femoris muscle of the hams. The results revealed that the highest weight loss was found in the dry-cured ham of LYD breed and the lowest weight loss was found in Ber dry-cured ham. The KNP dry-cured ham contain higher intramuscular fat level than other breed hams (p<0.05. It was observed that the dry-cured ham made from KNP breed had the lowest water activity value and highest salt content, while the LYD dry-cure ham had higher total volatile basic nitrogen content than the Ber and Du hams (p<0.05. Zinc, iron and total monounsaturated fatty acids levels were higher in KNP ham while polyunsaturated fatty acids levels were higher in Du ham when compared to other breed hams (p<0.05. Additionally, the KNP dry-cured ham possessed higher Commission International de l’Eclairage (CIE a* value, while the Du dry-cured ham had higher L*, CIE b* and hue angle values (p<0.05. Furthermore, breed significantly affected the sensory attributes of dry-cured hams with higher scores for color, aroma and taste found in KNP dry-cured ham as compared to other breed hams (p<0.05. The overall outcome of the study is that the breed has a potential effect on the specific chemical composition, texture, color and sensorial properties of dry-cured hams. These data could be useful for meat processors to select the suitable breeds for economical manufacturing of high quality dry-cured hams.

  18. Physicochemical and sensory properties of irradiated dry-cured ham

    International Nuclear Information System (INIS)

    Jin, Sang-Keun; Kim, Chul-Wook; Chung, Ki-Hwa; Jo, Kwang-Keun; Jeong, Jin-Yeon; Hur, In-Chul; Jung, Eun-Young; Joo, Seon-Tea; Yang, Han-Sul

    2012-01-01

    To determine the effect of different irradiation doses on ready-to-eat (RTE) dry-cured shoulder hams, physicochemical and sensory attributes were analyzed during 8 weeks of refrigerated storage. The results show that irradiation reduced the redness value and increased the 2-thiobarbituric acid-reactive substance (TBARS) value as well as the irradiation aroma during storage. However, ham samples irradiated with 2.5 and 5.0 kGy did not show significant changes in lightness values compared to the control sample during 8 weeks of storage. TBARS values were lower in the sample irradiated with 2.5 kGy than in the other irradiated samples. The total plate counts of the 5.0 kGy-irradiated samples were not measured after 0 weeks. Sensory panels found that the 2.5- and 5.0 kGy-irradiated samples had better overall acceptability scores than the other irradiated samples. It was concluded that treatments with lower levels of irradiation (≤5.0 kGy) can enhance the microbial safety and sensory acceptance of dry-cured shoulder hams. - Highlights: ► Effect of different irradiation doses on quality properties of dry-cured hams. ► The 2.5 kGy irradiated sample did not show any changes in lipid oxidation. ► Irradiation at 5.0 kGy has the potential to greatly decrease the TPC. ► Low-dose irradiation can improve the microbial safety and maintain the sensory acceptance.

  19. Degree of conversion and surface hardness of resin cement cured with different curing units.

    Science.gov (United States)

    Ozturk, Nilgun; Usumez, Aslihan; Usumez, Serdar; Ozturk, Bora

    2005-01-01

    The aim of this study was to evaluate the degree of conversion and Vickers surface hardness of resin cement under a simulated ceramic restoration with 3 different curing units: a conventional halogen unit, a high-intensity halogen unit, and a light-emitting diode system. A conventional halogen curing unit (Hilux 550) (40 s), a high-intensity halogen curing unit used in conventional and ramp mode (Optilux 501) (10 s and 20 s, respectively), and a light-emitting diode system (Elipar FreeLight) (20 s, 40 s) were used in this study. The dual-curing resin cement (Variolink II) was cured under a simulated ceramic restoration (diameter 5 mm, height 2 mm), and the degree of conversion and Vickers surface hardness were measured. For degree of conversion measurement, 10 specimens were prepared for each group. The absorbance peaks were recorded using the diffuse-reflection mode of Fourier transformation infrared spectroscopy. For Vickers surface hardness measurement, 10 specimens were prepared for each group. A load of 200 N was applied for 15 seconds, and 3 evaluations of each of the samples were performed. Degree of conversion achieved with Optilux 501 (20 s) was significantly higher than those of Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). For Vickers surface hardness measurement, Optilux 501 (20 s) produced the highest surface hardness value. No significant differences were found among the Hilux, Optilux 501 (10 s), Elipar FreeLight (20 s), and Elipar FreeLight (40 s). The high-intensity halogen curing unit used in ramp mode (20 s) produced harder resin cement surfaces than did the conventional halogen curing unit, high-intensity halogen curing unit used in conventional mode (10 s) and light-emitting diode system (20 s, 40 s), when cured through a simulated ceramic restoration.

  20. Effect of Particular Breed on the Chemical Composition, Texture, Color, and Sensorial Characteristics of Dry-cured Ham.

    Science.gov (United States)

    Seong, Pil Nam; Park, Kuyng Mi; Kang, Sun Moon; Kang, Geun Ho; Cho, Soo Hyun; Park, Beom Young; Van Ba, Hoa

    2014-08-01

    The present study demonstrates the impact of specific breed on the characteristics of dry-cured ham. Eighty thighs from Korean native pig (KNP), crossbreed (Landrace×Yorkshire)♀×Duroc♂ (LYD), Berkshire (Ber), and Duroc (Du) pig breeds (n = 10 for each breed) were used for processing of dry-cured ham. The thighs were salted with 6% NaCl (w/w) and 100 ppm NaNO2, and total processing time was 413 days. The effects of breed on the physicochemical composition, texture, color and sensory characteristics were assessed on the biceps femoris muscle of the hams. The results revealed that the highest weight loss was found in the dry-cured ham of LYD breed and the lowest weight loss was found in Ber dry-cured ham. The KNP dry-cured ham contain higher intramuscular fat level than other breed hams (pham made from KNP breed had the lowest water activity value and highest salt content, while the LYD dry-cure ham had higher total volatile basic nitrogen content than the Ber and Du hams (pham while polyunsaturated fatty acids levels were higher in Du ham when compared to other breed hams (pham possessed higher Commission International de l'Eclairage (CIE) a* value, while the Du dry-cured ham had higher L*, CIE b* and hue angle values (phams with higher scores for color, aroma and taste found in KNP dry-cured ham as compared to other breed hams (pcolor and sensorial properties of dry-cured hams. These data could be useful for meat processors to select the suitable breeds for economical manufacturing of high quality dry-cured hams.

  1. An Examination of the Chemistry of Peroxycarboxylic Nitric Anhydrides and Related Volatile Organic Compounds During Texas Air Quality Study 2000 Using Ground-Based Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, James M.; Jobson, B Tom T.; Kuster, W. C.; Goldan, P. D.; Murphy, Paul; Williams, Eric; Frost, G. J.; Riemer, D.; Apel, Eric; Stroud, C.; Wiedinmyer, Christine; Fehsenfeld, Fred C.

    2003-08-19

    Measurements of peroxycarboxylic nitric anhydrides (PANs) along with related volatile organic compounds (VOCs) were made at the La Porte super site during the TexAQS 2000 Houston study. The PAN mixing ratios ranged up to 6.5 ppbv and were broadly correlated with O3, characteristic of a highly polluted urban environment. The anthropogenic PAN homologue concentrations were generally consistent with those found in other urban environments; peroxypropionic nitric anhydride (PPN) averaged 15%, and peroxyisobutyric nitric anhydride (PiBN) averaged 3% of PAN,. Some periods were noted where local petrochemical sources resulted in anomalous PANs chemistry. This effect was especially noticeable in the case of peroxyacrylic nitric anhydride (APAN) where local sources of 1,3-butadiene and acrolein resulted in APAN as high as 30% of PAN. Peroxymethacrylic nitric anhydride (MPAN) was a fairly minor constituent of the PANs except for two periods on 4 and 5 September when air masses from high biogenic hydrocarbons (BHC) areas were observed. BHC chemistry was not a factor in the highest ozone pollution episodes in Houston but may have an impact on daily average ozone levels in some circumstances.

  2. Standardized Cloning and Curing of Plasmids

    DEFF Research Database (Denmark)

    Lauritsen, Ida; Kim, Se Hyeuk; Porse, Andreas

    2018-01-01

    and exchange of genetic parts in the Standard European Vectors Architecture (SEVA) vector system. Additionally, to facilitate rapid testing and iterative bioengineering using different vector designs, we provide a one-step protocol for a universal CRISPR-Cas9-based plasmid curing system (pFREE) and demonstrate...

  3. Weak interfaces for UV cure nanoimprint lithography

    Science.gov (United States)

    Houle, Frances; Fornof, Ann; Simonyi, Eva; Miller, Dolores; Truong, Hoa

    2008-03-01

    Nanoimprint lithography using a photocurable organic resist provides a means of patterning substrates with a spatial resolution in the few nm range. The usefulness of the technique is limited by defect generation during template removal, which involves fracture at the interface between the template and the newly cured polymer. Although it is critical to have the lowest possible interfacial fracture toughness (Gc less than 0.1 Jm-2) to avoid cohesive failure in the polymer, there is little understanding on how to achieve this using reacting low viscosity resist fluids. Studies of debonding of a series of free-radical cured polyhedral silsesquioxane crosslinker formulations containing selected reactive diluents from fluorosilane-coated quartz template materials will be described. At constant diluent fraction the storage modulus of cured resists follows trends in initial reaction rate, not diluent Tg. Adhesion is uncorrelated with both Tg and storage modulus. XPS studies of near-interface compositions indicate that component segregation within the resist fluid on contact with the template, prior to cure, plays a significant role in controlling the fracture process.

  4. Radiation cured coatings for fiber optics

    International Nuclear Information System (INIS)

    Ketley, A.D.; Morgan, C.R.

    1978-01-01

    A continuous protective coating is formed on a fiber optic by coating the fiber optic in a bath of a liquid radiation curable composition at a temperature up to 90 0 C and exposing the coated conductor to ultraviolet or high energy ionizing radiation to cure the coating

  5. Low Temperature Cure Powder Coatings (LTCPC)

    Science.gov (United States)

    2010-10-01

    Dr. Glen Merfeld, General Electric Global Research evaluated and optimized the formulation, and cure and performance parameters of candidate LTCPC...Unacceptable test result = Marginal test result = Acceptable test result 80 therefore suffer from brittleness at extremely low temperatures. NASA’s

  6. Enhanced microactuation with magnetic field curing of ...

    Indian Academy of Sciences (India)

    ples have been enhanced by two times when compared with that of zero field cured samples. The effect of .... Gauge of wire ... electrolitic-300 mesh (84.67 µm) LR, Product No. ... be in the body centered cubic phase with a lattice parameter.

  7. Biomimetic porous high-density polyethylene/polyethylene- grafted-maleic anhydride scaffold with improved in vitro cytocompatibility.

    Science.gov (United States)

    Sharma, Swati; Bhaskar, Nitu; Bose, Surjasarathi; Basu, Bikaramjit

    2018-05-01

    A major challenge for tissue engineering is to design and to develop a porous biocompatible scaffold, which can mimic the properties of natural tissue. As a first step towards this endeavour, we here demonstrate a distinct methodology in biomimetically synthesized porous high-density polyethylene scaffolds. Co-extrusion approach was adopted, whereby high-density polyethylene was melt mixed with polyethylene oxide to form an immiscible binary blend. Selective dissolution of polyethylene oxide from the biphasic system revealed droplet-matrix-type morphology. An attempt to stabilize such morphology against thermal and shear effects was made by the addition of polyethylene- grafted-maleic anhydride as a compatibilizer. A maximum ultimate tensile strength of 7 MPa and elastic modulus of 370 MPa were displayed by the high-density polyethylene/polyethylene oxide binary blend with 5% maleated polyethylene during uniaxial tensile loading. The cell culture experiments with murine myoblast C2C12 cell line indicated that compared to neat high-density polyethylene and high-density polyethylene/polyethylene oxide, the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride scaffold significantly increased muscle cell attachment and proliferation with distinct elongated threadlike appearance and highly stained nuclei, in vitro. This has been partly attributed to the change in surface wettability property with a reduced contact angle (∼72°) for 5% PE- g-MA blends. These findings suggest that the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride can be treated as a cell growth substrate in bioengineering applications.

  8. Short-chain grafting of tetrahydrofuran and 1,4-dioxane cycles on vinylchloride-maleic anhydride copolymer

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Mass increase of vinylchloride-maleic anhydride (VC-MA copolymer samples aged in tetrahydrofuran (THF or in 1,4-dioxane results from chemical interaction of VC-MA macromolecules with 1,4-dioxane or THF. Microstructure of the products of such modification was proved by infrared spectroscopy (IR- and nuclear magnetic resonance spectroscopy (13C NMR and 1H NMR. Mechanism of modification has been proposed. The results of microstructure research of VC-MA samples aged in THF and in 1,4-dioxane coincide with already known data on the reactions of opening of these and other oxygen-containing cycles under mild conditions.

  9. Talking Cure Models: A Framework of Analysis

    Directory of Open Access Journals (Sweden)

    Christopher Marx

    2017-09-01

    Full Text Available Psychotherapy is commonly described as a “talking cure,” a treatment method that operates through linguistic action and interaction. The operative specifics of therapeutic language use, however, are insufficiently understood, mainly due to a multitude of disparate approaches that advance different notions of what “talking” means and what “cure” implies in the respective context. Accordingly, a clarification of the basic theoretical structure of “talking cure models,” i.e., models that describe therapeutic processes with a focus on language use, is a desideratum of language-oriented psychotherapy research. Against this background the present paper suggests a theoretical framework of analysis which distinguishes four basic components of “talking cure models”: (1 a foundational theory (which suggests how linguistic activity can affect and transform human experience, (2 an experiential problem state (which defines the problem or pathology of the patient, (3 a curative linguistic activity (which defines linguistic activities that are supposed to effectuate a curative transformation of the experiential problem state, and (4 a change mechanism (which defines the processes and effects involved in such transformations. The purpose of the framework is to establish a terminological foundation that allows for systematically reconstructing basic properties and operative mechanisms of “talking cure models.” To demonstrate the applicability and utility of the framework, five distinct “talking cure models” which spell out the details of curative “talking” processes in terms of (1 catharsis, (2 symbolization, (3 narrative, (4 metaphor, and (5 neurocognitive inhibition are introduced and discussed in terms of the framework components. In summary, we hope that our framework will prove useful for the objective of clarifying the theoretical underpinnings of language-oriented psychotherapy research and help to establish a more

  10. Improved Concrete Materials with Hydrogel-Based Internal Curing Agents

    Directory of Open Access Journals (Sweden)

    Matthew J. Krafcik

    2017-11-01

    Full Text Available This research article will describe the design and use of polyelectrolyte hydrogel particles as internal curing agents in concrete and present new results on relevant hydrogel-ion interactions. When incorporated into concrete, hydrogel particles release their stored water to fuel the curing reaction, resulting in reduced volumetric shrinkage and cracking and thus increasing concrete service life. The hydrogel’s swelling performance and mechanical properties are strongly sensitive to multivalent cations that are naturally present in concrete mixtures, including calcium and aluminum. Model poly(acrylic acid(AA-acrylamide(AM-based hydrogel particles with different chemical compositions (AA:AM monomer ratio were synthesized and immersed in sodium, calcium, and aluminum salt solutions. The presence of multivalent cations resulted in decreased swelling capacity and altered swelling kinetics to the point where some hydrogel compositions displayed rapid deswelling behavior and the formation of a mechanically stiff shell. Interestingly, when incorporated into mortar, hydrogel particles reduced mixture shrinkage while encouraging the formation of specific inorganic phases (calcium hydroxide and calcium silicate hydrate within the void space previously occupied by the swollen particle.

  11. An emerging alternative to thermal curing: Electron curing of fiber-reinforced composites

    International Nuclear Information System (INIS)

    Singh, A.; Saunders, C.B.; Lopata, V.J.; Kremers, W.; Chung, M.

    1995-01-01

    Electron curing of fiber-reinforced composites to produce materials with good mechanical properties has been demonstrated by the authors' work, and by Aerospatiale. The attractions of this technology are the technical and processing advantages offered over thermal curing, and the projected cost benefits. Though the work so far has focused on the higher value composites for the aircraft and aerospace industries, the technology can also be used to produce composites for the higher volume industries, such as transportation and automotive

  12. Curing pasted plates for lead/acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Napoleon, E.S.

    1987-02-15

    This paper covers various aspects of the hydroset process and final drying of battery plates in a controlled chamber. Through the use of such chambers, battery makers are obtaining finished plates of consistent quality in 48 h or less, including final drying. Added benefits include: (i) reduced free-lead in plates; (ii) reduced floor space requirements; (iii) better knitting of paste to grid; (iv) reduced inventories; (v) reduced battery rejects.

  13. Alternating copolymerization of propylene oxide with biorenewable terpene-based cyclic anhydrides: a sustainable route to aliphatic polyesters with high glass transition temperatures.

    Science.gov (United States)

    Van Zee, Nathan J; Coates, Geoffrey W

    2015-02-23

    The alternating copolymerization of propylene oxide with terpene-based cyclic anhydrides catalyzed by chromium, cobalt, and aluminum salen complexes is reported. The use of the Diels-Alder adduct of α-terpinene and maleic anhydride as the cyclic anhydride comonomer results in amorphous polyesters that exhibit glass transition temperatures (Tg ) of up to 109 °C. The polymerization conditions and choice of catalyst have a dramatic impact on the molecular weight distribution, the relative stereochemistry of the diester units along the polymer chain, and ultimately the Tg of the resulting polymer. The aluminum salen complex exhibits exceptional selectivity for copolymerization without transesterification or epimerization side reactions. The resulting polyesters are highly alternating and have high molecular weights and narrow polydispersities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Degradation and contamination of perfluorinated sulfonic acid membrane due to swelling-dehydration cycles

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Morgen, Per; Skou, Eivind Morten

    Formation of sulfonic anhydride S-O-S (from the condensation of sulfonic acids) was known one of the important degradation mechanisms [i] for Nafion membrane under hydrothermal aging condition, which is especially critical for hydrogen fuel cells. Similar mechanism would also have be desirable...... to the membrane degradation in direct methanol fuel cells (DMFCs), where liquid water has direct contact with the electrolyte. An ex-situ experiment was established with swelling-dehydration cycles on the membrane. However, formation of sulfonic anhydride was not detected during the entire treatment; instead...

  15. A flexible cure rate model with dependent censoring and a known cure threshold.

    Science.gov (United States)

    Bernhardt, Paul W

    2016-11-10

    We propose a flexible cure rate model that accommodates different censoring distributions for the cured and uncured groups and also allows for some individuals to be observed as cured when their survival time exceeds a known threshold. We model the survival times for the uncured group using an accelerated failure time model with errors distributed according to the seminonparametric distribution, potentially truncated at a known threshold. We suggest a straightforward extension of the usual expectation-maximization algorithm approach for obtaining estimates in cure rate models to accommodate the cure threshold and dependent censoring. We additionally suggest a likelihood ratio test for testing for the presence of dependent censoring in the proposed cure rate model. We show through numerical studies that our model has desirable properties and leads to approximately unbiased parameter estimates in a variety of scenarios. To demonstrate how our method performs in practice, we analyze data from a bone marrow transplantation study and a liver transplant study. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Techno-economic benefits of radiation curing: a comparison studies

    Energy Technology Data Exchange (ETDEWEB)

    French, D [Universal Wood Inc., Lousville (United States)

    1994-12-31

    In comparing radiation cure versus conventional heat cure systems, the factors are considered in this studies i.e. environmental laws - includes the future regulations concerning volatile organic emissions and waste disposal may weigh heavily in the decision.

  17. Determinant of flexible Parametric Estimation of Mixture Cure ...

    African Journals Online (AJOL)

    PROF. OLIVER OSUAGWA

    2015-12-01

    Dec 1, 2015 ... Suitability of four parametric mixture cure models were considered namely; Log .... regression analysis which relies on the ... The parameter of mixture cure fraction model was ..... Stochastic Models of Tumor Latency and Their.

  18. Effects of the different atmospheric steam curing processes on the ...

    Indian Academy of Sciences (India)

    hardness when exposed to different atmospheric steam curing temperatures. ... Use of self-compacting concretes (SCCs) lowered the noise level on the ... Although maximum temperature limit values in curing locations should be from 40 to ...

  19. Solution blow spun nanocomposites of poly(lactic acid)/cellulose nanocrystals from Eucalyptus kraft pulp

    Science.gov (United States)

    Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNCMA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower the...

  20. Novel self-associative and multiphase nanostructured soft carriers based on amphiphilic hyaluronic acid derivatives

    DEFF Research Database (Denmark)

    Eenschooten, Corinne; Vaccaro, Andrea; Delie, Florence

    2012-01-01

    The purpose of the present study was to investigate the physicochemical properties in aqueous media of amphiphilic hyaluronic acid (HA) derivatives obtained by reaction of HA’s hydroxyl groups with octenyl succinic anhydride (OSA). The self-associative properties of the resulting octenyl succinic...

  1. Silicone rubber curing by high intensity infrared radiation

    International Nuclear Information System (INIS)

    Huang, T.; Tsai, J.; Cherng, C.; Chen, J.

    1994-01-01

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating. copyright 1995 American Institute of Physics

  2. Modeling the curing process of thermosetting resin matrix composites

    Science.gov (United States)

    Loos, A. C.

    1986-01-01

    A model is presented for simulating the curing process of a thermosetting resin matrix composite. The model relates the cure temperature, the cure pressure, and the properties of the prepreg to the thermal, chemical, and rheological processes occurring in the composite during cure. The results calculated with the computer code developed on the basis of the model were compared with the experimental data obtained from autoclave-curved composite laminates. Good agreement between the two sets of results was obtained.

  3. Electron Beam Curing of Polymer Matrix Composites - CRADA Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howell, Dave [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1997-05-01

    The major cost driver in manufacturing polymer matrix composite (PMC) parts and structures, and one of the elements having the greatest effect on their quality and performance, is the standard thermal cure process. Thermal curing of PMCs requires long cure times and high energy consumption, creates residual thermal stresses in the part, produces volatile toxic by-products, and requires expensive tooling that is tolerant of the high cure temperatures.

  4. Luminescence spectroscopy applied to a study of the curing process of diglycidyl-ether of bisphenol-A (DGEBA

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Mendonça Sales

    2005-09-01

    Full Text Available This work involved the application of luminescence spectroscopy under steady-state conditions to study the curing process of the epoxy resin diglycidyl-ether of bisphenol-A (DGEBA using the curing agents 4,4'-diaminodiphenylmethane (DDM and 4,4'-diaminodiphenylsulfone (DDS. Two fluorescence methods were employed: the intrinsic method related to the polymeric matrix and the extrinsic method, using the molecular probe 9-anthroic acid (9-AA. Stoichiometric mixtures, with and without 9-AA, were heated to 120 °C at a 5 °C/min heating rate. These samples were then cured at 120 °C for a further 2 hours and allowed to cool to room temperature for 20 minutes. The results obtained by the two methods indicate that the cross-linking reaction can be monitored by analyzing the spectral changes of the emission bands of DGEBA, curing agents and 9-AA.

  5. Light-Induced C-H Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides.

    Science.gov (United States)

    Cantillo, David; Mateos, Carlos; Rincon, Juan A; de Frutos, Oscar; Kappe, C Oliver

    2015-09-07

    Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Using maleic anhydride functionalized graphene oxide for improving the interfacial properties of carbon fiber/BMI composites

    Directory of Open Access Journals (Sweden)

    W. Li

    2016-11-01

    Full Text Available Maleic anhydride functionalized graphene oxide (MAH-GO was synthesized and then introduced into carbon fiber (CF reinforced bismaleimide (BMI composites, with the aim of improving the interfacial adhesion strength between CF and BMI resin. Various characterization techniques including Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectra (XPS and thermogravimetric analysis (TGA demonstrated that the maleic anhydride has been successfully grafted onto the GO surfaces. The study showed that the interlaminar shear strength (ILSS and flexural properties of CF/BMI composites were all improved by the incorporation of GO and MAH-GO, and the MAH-GO showed the substantially improved effect due to the strong interaction between the MAH-GO and the resin matrix. The maximum increment of the ILSS, flexural strength and flexural modulus of composites were 24.4, 28.7 and 49.7%, respectively. Scanning electron microscope (SEM photographs of the fracture surfaces revealed that the interfacial bonding between CF and resin matrix was significantly strengthened by the addition of MAH-GO. The results suggest that this feasible method may be an ideal substitute for the traditional method in the interfacial modification of composites.

  7. Kerogen chemistry 5. Anhydride formation in, solvent swelling of, and loss of organics on demineralization of Kimmeridge shales

    International Nuclear Information System (INIS)

    Larsen, John W.; Flores, Carlos Islas

    2008-01-01

    The results of three short and related, but experimentally independent, studies of 4 Kimmeridge shales and their kerogens are reported. Differential scanning calorimeter (DSC) studies of the kerogens reveal that three of the four show evidence of anhydride formation when heated at 20 C/min between 50 C and 180 C. There is no regular rank dependence of anhydride formation. After solvent swelling in tetrahydrofuran (THF), extracted organics were isolated from the THF and the recovered kerogens were swollen a second time in fresh THF. The second solvent swelling ratios were slightly larger than the first because the presence of the extracts in the original THF lowers solvent activity thus reducing swelling. The shales were demineralized in the usual way except that methylene chloride was added to dissolve any organics that were liberated from the rock as a consequence of mineral dissolution. Small amounts of organics were found in the methylene chloride supporting Price and Clayton's conclusion that organics are expelled from the kerogen and are present in lacunae in the minerals. (author)

  8. Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride with low molecular weight polyethylenimine for efficient gene delivery

    Directory of Open Access Journals (Sweden)

    Duan XP

    2012-09-01

    Full Text Available Xiaopin Duan,1,2 Jisheng Xiao,2 Qi Yin,2 Zhiwen Zhang,2 Shirui Mao,1 Yaping Li21School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 2Center of Pharmaceutics, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, ChinaBackground and methods: A new amphiphilic comb-shaped copolymer (SP was synthesized by conjugating poly(styrene-co-maleic anhydride with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer.Results: The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13–30 mV and a small particle size (130–200 nm at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines.Conclusion: This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery.Keywords: poly(styrene-co-maleic anhydride, polyethylenimine, DNA, gene delivery

  9. 7 CFR 30.12 - Fire-cure.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fire-cure. 30.12 Section 30.12 Agriculture Regulations... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.12 Fire-cure. To cure tobacco under artificial atmospheric conditions by the use of open fires, the smoke and...

  10. Radiation curing technology progress and its industrial applications in Japan

    International Nuclear Information System (INIS)

    Ukachi, Takashi

    2003-01-01

    Optics, electronics and display industries are now the driving forces for the Japanese radiation curing technology. The purpose of this paper is to overview the newly developed radiation curing technology in Japan, in particular, its industrial applications, and to present the market figures in radiation curing applications, which were surveyed by RadTech Japan in 2002 afresh. (author)

  11. UV curing by radical, cationic and concurrent radicalcationic polymerization

    International Nuclear Information System (INIS)

    Pappas, S.P.

    1984-01-01

    UV and EB curing represent complementary technologies with respective advantages and disadvantages. This paper deals with the design and evaluation of UV curable coatings to optimize cure rate and film properties. Topics included are state-of-the-art photoinitiator systems, light intensity effects, retardation of air-inhibition, adhesion, and amplification of photons for enhanced speed of cure

  12. Techniques and materials for internal water curing of concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Lura, Pietro

    2006-01-01

    This paper gives an overview of different techniques for incorporation of internal curing water in concrete. Internal water curing can be used to mitigate self-desiccation and selfdesiccation shrinkage. Some concretes may need 50 kg/m3 of internal curing water for this purpose. The price...

  13. effect of curing methods on the compressive strength of concrete

    African Journals Online (AJOL)

    High curing temperature (up to 212◦F or. 100◦C) ... are affected by curing and application of the ... for concrete production, it is important to ... Concrete properties and durability are signif- ... Curing compounds are merely temporary coatings on.

  14. Determinant of flexible Parametric Estimation of Mixture Cure ...

    African Journals Online (AJOL)

    AIC, mean time to cure), variance and cure fraction (c) were used to determine the flexible Parametric Cure Fraction Model among the considered models. Gastric Cancer data from 76 patients received adjuvant CRT and 125 receiving resection (surgery) alone were used to confirm the suitability of the models. The data was ...

  15. Effect of curing time on microstructure and mechanical strength ...

    Indian Academy of Sciences (India)

    The aim of this paper is to study the influence of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Mechanical strength of alkali activated mortars cured at 65 °C was assessed for different curing times (4–168 h) using 10 ...

  16. Environmental and conservation considerations for electron curing

    International Nuclear Information System (INIS)

    Nablo, S.V.; Fletcher, P.M.

    1992-01-01

    This paper reviews the more important features of electron curing pertaining to environmental protection and conservation. The high electrical conversion efficiencies of these devices measured at output power levels to 200 kilowatts are reviewed with attention to energy transport to the product. The comparative energetics of free radical initiated addition chemistry with that of the more conventional condensation polymerized systems are presented. Some details of recent studies of the repulpability and de-inkability of electron cured products are presented with mill scale trials showing successful recycling with up to 75 % EB processed material in the waste. The ability of energetic electrons to effectively replace toxic chemicals such as H 2 O 2 and ethylene oxide in product sterilization will be presented with a discussion of the regulatory aspects of this process for medical device applications. (author)

  17. Coating and curing apparatus and methods

    Science.gov (United States)

    Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

    2015-02-24

    Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

  18. Cushing's syndrome: aftermath of the cure

    OpenAIRE

    Pivonello, Rosario; De Martino, Maria Cristina; De Leo, Monica; Tauchmanovà, Libuse; Faggiano, Antongiulio; Lombardi, Gaetano; Colao, Annamaria

    2007-01-01

    Cushing's syndrome (CS) is a chronic and systemic disease caused by endogenous or exogenous hypercortisolism, associated with an increase of mortality rate due to the clinical consequences of glucocorticoid excess, especially cardiovascular diseases. After cure, usually obtained by the surgical removal of the tumor responsible for the disease, the normalization of cortisol secretion is not constantly followed by the recovery of the clinical complications developed during the active disease, a...

  19. Cure Behavior and Thermal Properties of Diepoxidized Cardanol Resin Cured by Electron Beam Process

    International Nuclear Information System (INIS)

    Cho, Donghwan; Cheon, Jinsil

    2013-01-01

    Thermal curing of epoxy resin requires high temperature, time-consuming process and the volatilization of hardener. It has known that electron beam curing of epoxy resin is a fast process and occurs at low or room temperature that help reduce residual mechanical stresses in thermosetting polymers. Diepoxidized cardanol (DEC) can be synthesized by an enzymatic method from cashew nut shell liquid (CNSL), that constitutes nearly one-third of the total nut weight. A large amount of CNSL can be formed as a byproduct of the mechanical processes used to render the cashew kerneledible and its total production approaches one million tons annually, which can be bio-degradable and replace the industrial thermosetting plastics. It is expected that DEC may be cured as in an epoxy resin, which was constituted on two epoxide group and long alkyl chain, and two-types of onium salts (cationic initiator) were used as a photo-initiator. The experimental variables of this study are type and concentration of photo-initiators and electron beam dosage. In this study, the effects of initiator type and concentration on the cure behavior and the thermal properties of DEC resin processed by using electron beam technology were studied using FT-IR, TGA, TMA, DSC, and DMA. Figure 1 is the FT-IR results, showing the change of chemical structure of pure DEC and electron beam cured DEC. The characteristic absorption peak of epoxide group appeared at 850cm -1 . The shape and the height were reduced when the sample was irradiated with electron beam. From this result, the epoxide groups is DEC were opened by electron beam and cured. After then, electron beam cured DEC was investigated the effect of forming 3-dimensional network

  20. Cure Behavior and Thermal Properties of Diepoxidized Cardanol Resin Cured by Electron Beam Process

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Donghwan; Cheon, Jinsil [Kumoh National Institute of Technology, Gumi (Korea, Republic of)

    2013-07-01

    Thermal curing of epoxy resin requires high temperature, time-consuming process and the volatilization of hardener. It has known that electron beam curing of epoxy resin is a fast process and occurs at low or room temperature that help reduce residual mechanical stresses in thermosetting polymers. Diepoxidized cardanol (DEC) can be synthesized by an enzymatic method from cashew nut shell liquid (CNSL), that constitutes nearly one-third of the total nut weight. A large amount of CNSL can be formed as a byproduct of the mechanical processes used to render the cashew kerneledible and its total production approaches one million tons annually, which can be bio-degradable and replace the industrial thermosetting plastics. It is expected that DEC may be cured as in an epoxy resin, which was constituted on two epoxide group and long alkyl chain, and two-types of onium salts (cationic initiator) were used as a photo-initiator. The experimental variables of this study are type and concentration of photo-initiators and electron beam dosage. In this study, the effects of initiator type and concentration on the cure behavior and the thermal properties of DEC resin processed by using electron beam technology were studied using FT-IR, TGA, TMA, DSC, and DMA. Figure 1 is the FT-IR results, showing the change of chemical structure of pure DEC and electron beam cured DEC. The characteristic absorption peak of epoxide group appeared at 850cm{sup -1}. The shape and the height were reduced when the sample was irradiated with electron beam. From this result, the epoxide groups is DEC were opened by electron beam and cured. After then, electron beam cured DEC was investigated the effect of forming 3-dimensional network.

  1. Electron Beam curing of intaglio inks

    International Nuclear Information System (INIS)

    O'Brien, T.

    1984-01-01

    Press trials conducted by the US Bureau of Engraving and Printing at the National Bank of Denmark in September 8-21, 1982, clearly indicated the feasibility of Electron Beam (EB) curing for web intaglio printing. These trials, some at continuous press runs of up to six hours, gave positive results for virtually all our requirements including: print quality, press speeds, ability to print both sides of the web on one pass through a press, acceptable ink curing at one megarad or less, and minimum substrate deterioration or loss of moisture. In addition, these trials demonstrated many advantages over thermal curing which is the only other alternative to two sided printing in one pass through the press. These advantages can be found in product quality, a cleaner environment, and in economics. This development program is still in progress with efforts now directed towards adapting EB ink technology to the latest developments in intaglio printing, i.e. aqueous cylinder wiping which requires EB inks to be water dispersable. Also the stability of materials in contact with EB inks is being investigated

  2. Electron beam curing of intaglio inks

    International Nuclear Information System (INIS)

    O'Brien, T.

    1985-01-01

    Press trials conducted by the U.S. Bureau of Engraving and Printing at the National Bank of Denmark clearly indicated the feasibility of Electron Beam (E.B.) curing for web intaglio printing . These trials, some at continuous press runs of up to six hours, gave positive results for virtually all our requirements including: print quality, press speeds, ability to print both sides of the web on one pass through a press, acceptable ink curing at one megarad or less, and minimum substrate deterioration or loss of moisture. In addition, these trials demonstrated many advantages over thermal curing which is the only other alternative to two sided printing in one pass through the press. These advantages can be found in product quality, a cleaner environment, and in economics. This development program is still in progress with efforts now directed towards adapting E.B. ink technology to the latest developments in intaglio printing, i.e. aqueous cylinder wiping which requires E.B. inks to be water dispersable. Also the stability of materials in contact with E.B. inks is being investigated. (author)

  3. Tools for Visualizing HIV in Cure Research.

    Science.gov (United States)

    Niessl, Julia; Baxter, Amy E; Kaufmann, Daniel E

    2018-02-01

    The long-lived HIV reservoir remains a major obstacle for an HIV cure. Current techniques to analyze this reservoir are generally population-based. We highlight recent developments in methods visualizing HIV, which offer a different, complementary view, and provide indispensable information for cure strategy development. Recent advances in fluorescence in situ hybridization techniques enabled key developments in reservoir visualization. Flow cytometric detection of HIV mRNAs, concurrently with proteins, provides a high-throughput approach to study the reservoir on a single-cell level. On a tissue level, key spatial information can be obtained detecting viral RNA and DNA in situ by fluorescence microscopy. At total-body level, advancements in non-invasive immuno-positron emission tomography (PET) detection of HIV proteins may allow an encompassing view of HIV reservoir sites. HIV imaging approaches provide important, complementary information regarding the size, phenotype, and localization of the HIV reservoir. Visualizing the reservoir may contribute to the design, assessment, and monitoring of HIV cure strategies in vitro and in vivo.

  4. Cushing's syndrome: aftermath of the cure.

    Science.gov (United States)

    Pivonello, Rosario; De Martino, Maria Cristina; De Leo, Monica; Tauchmanovà, Libuse; Faggiano, Antongiulio; Lombardi, Gaetano; Colao, Annamaria

    2007-11-01

    Cushing's syndrome (CS) is a chronic and systemic disease caused by endogenous or exogenous hypercortisolism, associated with an increase of mortality rate due to the clinical consequences of glucocorticoid excess, especially cardiovascular diseases. After cure, usually obtained by the surgical removal of the tumor responsible for the disease, the normalization of cortisol secretion is not constantly followed by the recovery of the clinical complications developed during the active disease, and it is often followed by the development of novel clinical manifestations induced by the fall of cortisol levels. These evidences were mostly documented in patients with pituitary-dependent CS, after surgical resection of the pituitary tumor. Indeed, despite an improvement of the mortality rate, metabolic syndrome and the consequent cardiovascular risk have been found to partially persist after disease remission, strictly correlated to the insulin resistance. Skeletal diseases, mainly osteoporosis, improve after normalization of cortisol levels but require a long period of time or the use of specific treatment, mainly bisphosphonates, to reach the normalization of bone mass. A relevant improvement or resolution of mental disturbances has been described in patients cured from CS, although in several cases, cognitive decline persisted and psychological or psychiatric improvement was erratic, delayed, or incomplete. On the other hand, development or exacerbation of autoimmune disorders, mainly thyroid autoimmune diseases, was documented in predisposed patients with CS after disease remission. The totality of these complications persisting or occurring after successful treatment contribute to the impairment of quality of life registered in patients with CS after disease cure.

  5. Seasonal variability of monosaccharide anhydrides, resin acids, methoxyphenols and saccharides in PM2.5 in Brno, the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Mikuška, Pavel; Kubátková, Nela; Křůmal, Kamil; Večeřa, Zbyněk

    2017-01-01

    Roč. 8, č. 3 (2017), s. 576-586 ISSN 1309-1042 R&D Projects: GA ČR(CZ) GA14-25558S; GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:68081715 Keywords : atmospheric aerosols * PM2.5 * organic compounds Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 1.637, year: 2016

  6. Study on the heat-resistant EB curing composites

    International Nuclear Information System (INIS)

    Bao Jianwen; Li Yang; Li Fengmei

    2000-01-01

    There are many advantages in the EB-curing process of composites. Heat-resistant EB-curing composites could substitute for polyimide composites used in aeronautical engine. The effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical thermal analysis (DMTA). The experiment result shows that the mechanical property of the composites cured by EB could meet the needs of the aeronautical engine in 250degC. (author)

  7. Standard treatment regimens for nongonococcal urethritis have similar but declining cure rates: a randomized controlled trial.

    Science.gov (United States)

    Manhart, Lisa E; Gillespie, Catherine W; Lowens, M Sylvan; Khosropour, Christine M; Colombara, Danny V; Golden, Matthew R; Hakhu, Navneet R; Thomas, Katherine K; Hughes, James P; Jensen, Nicole L; Totten, Patricia A

    2013-04-01

    Azithromycin or doxycycline is recommended for nongonococcal urethritis (NGU); recent evidence suggests their efficacy has declined. We compared azithromycin and doxycycline in men with NGU, hypothesizing that azithromycin was more effective than doxycycline. From January 2007 to July 2011, English-speaking males ≥16 years, attending a sexually transmitted diseases clinic in Seattle, Washington, with NGU (visible urethral discharge or ≥5 polymorphonuclear leukocytes per high-power field [PMNs/HPF]) were eligible for this double-blind, parallel-group superiority trial. Participants received active azithromycin (1 g) + placebo doxycycline or active doxycycline (100 mg twice daily for 7 days) + placebo azithromycin. Urine was tested for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), Ureaplasma urealyticum biovar 2 (UU-2), and Trichomonas vaginalis (TV) using nucleic acid amplification tests. Clinical cure (urethral symptoms and absence of discharge) and microbiologic cure (negative tests for CT, MG, and/or UU-2) were determined after 3 weeks. Of 606 men, 304 were randomized to azithromycin and 302 to doxycycline; CT, MG, TV, and UU-2 were detected in 24%, 13%, 2%, and 23%, respectively. In modified intent-to-treat analyses, 172 of 216 (80%; 95% confidence interval [CI], 74%-85%) receiving azithromycin and 157 of 206 (76%; 95% CI, 70%-82%) receiving doxycycline experienced clinical cure (P = .40). In pathogen-specific analyses, clinical cure did not differ by arm, nor did microbiologic cure differ for CT (86% vs 90%, P = .56), MG (40% vs 30%, P = .41), or UU-2 (75% vs 70%, P = .50). No unexpected adverse events occurred. Clinical and microbiologic cure rates for NGU were somewhat low and there was no significant difference between azithromycin and doxycycline. Mycoplasma genitalium treatment failure was extremely common. Clinical Trials Registration.NCT00358462.

  8. Dietary supplementation with cysteine prevents adverse metabolic outcomes of repeated cures with paracetamol in old rats.

    Science.gov (United States)

    Mast, Carole; Pourpe, Charlène; Voyard, Guillaume; Rémond, Didier; Migné, Carole; Centeno, Delphine; Dardevet, Dominique; Savary-Auzeloux, Isabelle; Papet, Isabelle

    2017-12-01

    Cysteine (Cys), a conditionally indispensable amino acid, is required for the detoxification of paracetamol (acetaminophen, N-acetyl-para-aminophenol, 4-hydroxy-acetanilide, APAP), a drug of widespread use in older persons. We recently reported that repeated APAP cures could worsen sarcopenia in old rats, likely to be due to the impairment of Cys/GSH homoeostasis. The aim of the study was to evaluate whether a dietary Cys supplementation during APAP cures could improve Cys/GSH homoeostasis and thus preserve skeletal muscle. Male 21·5-month-old Wistar rats received three 2-week-long cures of APAP (1 % of diet) alone or with extra Cys (0·5 % of diet), intercalated with washout periods of 2 weeks (APAP and APAP-Cys groups, respectively). They were compared with untreated control rats (CT group). CT and APAP-Cys groups were pair-fed to the APAP group. Dietary Cys supplementation was efficient to prevent increase in liver mass (P<0·0001), decrease in liver GSH (P<0·0001), increase in blood GSH concentration (P<0·0001), and to some extent, decrease in plasma free Cys concentration (P<0·05), all induced by repeated APAP cures. The addition of Cys to APAP cures decreased plasma alanine transaminase (P<0·05), the fractional synthesis rate of liver proteins (P<0·01), and increased masses of extensor digitorum longus (P<0·01), and soleus (P<0·05), compared with the APAP group. Cys supplementation prevented alteration in Cys/GSH homoeostasis and increased some muscle masses in old rats under repeated cures with a non-toxic dose of APAP.

  9. Development of a fast curing tissue adhesive for meniscus tear repair.

    Science.gov (United States)

    Bochyńska, Agnieszka Izabela; Hannink, Gerjon; Janssen, Dennis; Buma, Pieter; Grijpma, Dirk W

    2017-01-01

    Isocyanate-terminated adhesive amphiphilic block copolymers are attractive materials to treat meniscus tears due to their tuneable mechanical properties and good adhesive characteristics. However, a drawback of this class of materials is their relatively long curing time. In this study, we evaluate the use of an amine cross-linker and addition of catalysts as two strategies to accelerate the curing rates of a recently developed biodegradable reactive isocyanate-terminated hyper-branched adhesive block copolymer prepared from polyethylene glycol (PEG), trimethylene carbonate, citric acid and hexamethylene diisocyanate. The curing kinetics of the hyper-branched adhesive alone and in combination with different concentrations of spermidine solutions, and after addition of 2,2-dimorpholinodiethylether (DMDEE) or 1,4-diazabicyclo [2.2.2] octane (DABCO) were determined using FTIR. Additionally, lap-shear adhesion tests using all compositions at various time points were performed. The two most promising compositions of the fast curing adhesives were evaluated in a meniscus bucket handle lesion model and their performance was compared with that of fibrin glue. The results showed that addition of both spermidine and catalysts to the adhesive copolymer can accelerate the curing rate and that firm adhesion can already be achieved after 2 h. The adhesive strength to meniscus tissue of 3.2-3.7 N was considerably higher for the newly developed compositions than for fibrin glue (0.3 N). The proposed combination of an adhesive component and a cross-linking component or catalyst is a promising way to accelerate curing rates of isocyanate-terminated tissue adhesives.

  10. A cure for HIV: is it in sight?

    Science.gov (United States)

    Pace, Matthew; Frater, John

    2014-07-01

    HIV is a devastating disease affecting millions of people worldwide despite the advent of successful antiretroviral therapy (ART). However, ART does not result in a cure and has to be taken for life. Accordingly, researchers are turning towards cure efforts, particularly in the light of two patients whose HIV has been seemingly eradicated. Numerous approaches and strategies have been considered for curing HIV, but no scalable and safe solution has yet been reached. With newly discovered difficulties in measuring the HIV reservoir, the main barrier to a cure, the only true test of cure is to stop ART and see whether the virus becomes detectable. However, it is possible that this treatment interruption may be associated with certain risks for patients. Here, we compare the current major approaches and recent advances for curing HIV, as well as discuss ways of evaluating HIV cure and the safety concerns involved.

  11. CURING OF POLYMERIC COMPOSITES USING MICROWAVE RESIN TRANSFER MOULDING (RTM

    Directory of Open Access Journals (Sweden)

    R. YUSOFF

    2007-08-01

    Full Text Available The main objective of this work is to compare the difference between microwave heating and conventional thermal heating in fabricating carbon/epoxy composites. Two types of epoxy resin systems were used as matrices, LY5052-HY5052 and DGEBA-HY917-DY073. All composite samples were fabricated using resin transfer moulding (RTM technique. The curing of the LY5052-HY5052-carbon and the DGEBA-HY917-DY073-carbon composite systems, were carried out at 100 °C and 120 °C, respectively. Microwave heating showed better temperature control than conventional heating, however, the heating rate of the microwave cured samples were slower than the conventionally cured samples. This was attributed to the lower power (250 W used when heating with microwaves compared to 2000 W used in conventional heating. Study of thermal characteristics as curing progressed showed that the polymerisation reaction occurred at a faster rate during microwave curing than in conventional curing for both the DGEBA and the LY/HY5052 carbon composite systems. The actual cure cycle was reduced from 60 minutes to 40 minutes when using microwaves for curing DGEBA-carbon composites. As for LY/HY5052-carbon composites, the actual cure cycle was reduced from 3 hours to 40 minutes. Both conventional and microwave heating yielded similar glass transition temperatures (120 °C for DGEBA systems and 130 °C for LY/HY5052 systems. Microwave cured composites had higher void contents than conventionally cured composites (2.2-2.8% and 1.8-2.4% for DGEBA and LY/HY5052 microwave cured composites, respectively, compared to 0.2-0.4% for both DGEBA and LY/HY5052 thermally cured composites. C-scan traces showed that all composites, regardless of methods of curing, had minimal defects.

  12. Experimental Study on the Curing Effect of Dredged Sediments with Three Types of Curing Agents

    Directory of Open Access Journals (Sweden)

    Yan Lei-Ming

    2016-01-01

    Full Text Available Sediment solidification technology is widely used to dispose dredged sediment, three types of curing agents were used in this study to solidified the dredged sediment from shallows in Nantong with three types of curing agents: JY, ZL and FJ. The results showed that the optimal additive amounts of these three curing agents were 140g JY, 16g ZL, 2.0g FJ per 1000g of the dredged sediment respectively, their 28d USC were up to 2.48 MPa, 2.96 MPa and 3.00 MPa. JY has obvious early strength effect, which of FJ is not that obvious, but the later-stage strength of sediment solidified by FJ are relatively higher.

  13. Greener Friedel-Crafts Acylation using Microwave-enhanced reactivity of Bismuth Triflate in the Friedel-Crafts Benzoylation of Aromatic Compounds with Benzoic Anhydride

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Nguyen, Hai Truong; Hansen, Poul Erik

    2017-01-01

    An efficient and facile bismuth trifluoromethanesulfonate-catalyzed benzoylation of aromatic compounds using benzoic anhydride under solvent-free microwave irradiation has been developed. The microwave-assisted Friedel-Crafts benzoylation results in good yields within short reaction times. Bismuth...

  14. Controlled radical copolymerization of styrene and maleic anhydride and the synthesis of novel polyolefin-based block copolymers by reversible addition-fragmentation chain-transfer (RAFT) polymerization

    NARCIS (Netherlands)

    Brouwer, de J.A.M.; Schellekens, M.A.J.; Klumperman, B.; Monteiro, M.J.; German, A.L.

    2000-01-01

    Reversible addn.-fragmentation chain transfer (RAFT) was applied to the copolymn. of styrene and maleic anhydride. The product had a low polydispersity and a predetd. molar mass. Novel, well-defined polyolefin-based block copolymers were prepd. with a macromol. RAFT agent prepd. from a com.

  15. Copper(II) sulfate pentahydrate (CuSO4.5H2O): a green catalyst for solventless acetylation of alcohols and phenols with acetic anhydride

    OpenAIRE

    Heravi,Majid M.; Behbahani,Farahnaz K.; Zadsirjan,Vahideh; Oskooie,Hossien A.

    2006-01-01

    Alcohols and phenols were efficiently acetylated with acetic anhydride in the presence of copper (II) sulfate at room temperature in high yields. Álcoois e fenóis foram acetilados eficientemente com anidrido acético na presença de sulfato de cobre (II) em temperatura ambiente, com altos rendimentos.

  16. Post-cure depth of cure of bulk fill dental resin-composites.

    Science.gov (United States)

    Alrahlah, A; Silikas, N; Watts, D C

    2014-02-01

    To determine the post-cure depth of cure of bulk fill resin composites through using Vickers hardness profiles (VHN). Five bulk fill composite materials were examined: Tetric EvoCeram(®) Bulk Fill, X-tra base, Venus(®) Bulk Fill, Filtek™ Bulk Fill, SonicFill™. Three specimens of each material type were prepared in stainless steel molds which contained a slot of dimensions (15 mm × 4 mm × 2 mm), and a top plate. The molds were irradiated from one end. All specimens were stored at 37°C for 24h, before measurement. The Vickers hardness was measured as a function of depth of material, at 0.3mm intervals. Data were analysed by one-way ANOVA using Tukey post hoc tests (α=0.05). The maximum VHN ranged from 37.8 to 77.4, whilst the VHN at 80% of max.VHN ranged from 30.4 to 61.9. The depth corresponding to 80% of max.VHN, ranged from 4.14 to 5.03 mm. One-way ANOVA showed statistically significant differences between materials for all parameters tested. SonicFill exhibited the highest VHN (pFill the lowest (p≤0.001). SonicFill and Tetric EvoCeram Bulk Fill had the greatest depth of cure (5.03 and 4.47 mm, respectively) and was significant's different from X-tra base, Venus Bulk Fill and Filtek Bulk Fill (p≤0.016). Linear regression confirmed a positive regression between max.VHN and filler loading (r(2)=0.94). Bulk fill resin composites can be cured to an acceptable post-cure depth, according to the manufacturers' claims. SonicFill and Tetric EvoCeram Bulk Fill had the greatest depth of cure among the composites examined. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Radiation curing--new technology of green industries facing 21st century

    International Nuclear Information System (INIS)

    Wang Jianguo; Teng Renrui

    2000-01-01

    The development of radiation curing was simply reviewed and the mechanism of UV curing and EB curing, the equipment and materials used in the radiation curing were also introduced. Compared with ordinary curing, the radiation curing has advantages of energy saving, high effectiveness and little pollution. It is a new technology of green industries facing the 21st century

  18. Electron beam curing of polymer matrix composites

    International Nuclear Information System (INIS)

    Janke, C.J.; Wheeler, D.; Saunders, C.

    1998-01-01

    The purpose of the CRADA was to conduct research and development activities to better understand and utilize the electron beam PMC curing technology. This technology will be used to replace or supplement existing PMC thermal curing processes in Department of Energy (DOE) Defense Programs (DP) projects and American aircraft and aerospace industries. This effort involved Lockheed Martin Energy Systems, Inc./Lockheed Martin Energy Research Corp. (Contractor), Sandia National Laboratories, and ten industrial Participants including four major aircraft and aerospace companies, three advanced materials companies, and three electron beam processing organizations. The technical objective of the CRADA was to synthesize and/or modify high performance, electron beam curable materials that meet specific end-use application requirements. There were six tasks in this CRADA including: Electron beam materials development; Electron beam database development; Economic analysis; Low-cost Electron Beam tooling development; Electron beam curing systems integration; and Demonstration articles/prototype structures development. The contractor managed, participated and integrated all the tasks, and optimized the project efforts through the coordination, exchange, and dissemination of information to the project participants. Members of the Contractor team were also the principal inventors on several electron beam related patents and a 1997 R and D 100 Award winner on Electron-Beam-Curable Cationic Epoxy Resins. The CRADA achieved a major breakthrough for the composites industry by having successfully developed high-performance electron beam curable cationic epoxy resins for use in composites, adhesives, tooling compounds, potting compounds, syntactic foams, etc. UCB Chemicals, the world's largest supplier of radiation-curable polymers, has acquired a license to produce and sell these resins worldwide

  19. A perspective on "cure" for Rett syndrome.

    Science.gov (United States)

    Clarke, Angus John; Abdala Sheikh, Ana Paula

    2018-04-02

    The reversal of the Rett syndrome disease process in the Mecp2 mouse model of Guy et al. (2007) has motivated families and researchers to work on this condition. The reversibility in adult mice suggests that there is potentially much to be gained from rational treatments applied to patients of any age. However, it may be difficult to strike the right balance between enthusiasm on the one hand and realism on the other. One effect of this has been a fragmentation of the "Rett syndrome community" with some groups giving priority to work aimed at a cure while fewer resources are devoted to medical or therapy-based interventions to enhance the quality of life of affected patients or provide support for their families.Several possible therapeutic approaches are under development that, it is claimed and hoped, may lead to a "cure" for patients with Rett syndrome. While all have a rationale, there are potential obstacles to each being both safe and effective. Furthermore, any strategy that succeeded in restoring normal levels of MECP2 gene expression throughout the brain carries potential pitfalls, so that it will be of crucial importance to introduce any clinical trials of such therapies with great care.Expectations of families for a radical, rational treatment should not be inflated beyond a cautious optimism. This is particularly because affected patients with us now may not be able to reap the full benefits of a "cure". Thus, interventions aimed at enhancing the quality of life of affected patients should not be forgone and their importance should not be minimised.

  20. Atypical cleavage of protonated N-fatty acyl amino acids derived from aspartic acid evidenced by sequential MS3 experiments.

    Science.gov (United States)

    Boukerche, Toufik Taalibi; Alves, Sandra; Le Faouder, Pauline; Warnet, Anna; Bertrand-Michel, Justine; Bouchekara, Mohamed; Belbachir, Mohammed; Tabet, Jean-Claude

    2016-12-01

    Lipidomics calls for information on detected lipids and conjugates whose structural elucidation by mass spectrometry requires to rationalization of their gas phase dissociations toward collision-induced dissociation (CID) processes. This study focused on activated dissociations of two lipoamino acid (LAA) systems composed of N-palmitoyl acyl coupled with aspartic and glutamic acid mono ethyl esters (as LAA (*D) and LAA (*E) ). Although in MS/MS, their CID spectra show similar trends, e.g., release of water and ethanol, the [(LAA (*D/*E) +H)-C 2 H 5 OH] + product ions dissociate via distinct pathways in sequential MS 3 experiments. The formation of all the product ions is rationalized by charge-promoted cleavages often involving stepwise processes with ion isomerization into ion-dipole prior to dissociation. The latter explains the maleic anhydride or ketene neutral losses from N-palmitoyl acyl aspartate and glutamate anhydride fragment ions, respectively. Consequently, protonated palmitoyl acid amide is generated from LAA (*D), whereas LAA (*E) leads to the [*E+H-H 2 O] + anhydride. The former releases ammonia to provide acylium, which gives the C n H (2n-1) and C n H (2n-3) carbenium series. This should offer structural information, e.g., to locate either unsaturation(s) or alkyl group branching present on the various fatty acyl moieties of lipo-aspartic acid in further studies based on MS n experiments.

  1. Preparation and Characterization of Extruded Composites Based on Polypropylene and Chitosan Compatibilized with Polypropylene-Graft-Maleic Anhydride

    Science.gov (United States)

    Carrasco-Guigón, Fernando Javier; Rodríguez-Félix, Dora Evelia; Castillo-Ortega, María Mónica; Santacruz-Ortega, Hisila C.; Burruel-Ibarra, Silvia E.; Encinas-Encinas, Jose Carmelo; Plascencia-Jatomea, Maribel; Herrera-Franco, Pedro Jesus; Madera-Santana, Tomas Jesus

    2017-01-01

    The preparation of composites of synthetic and natural polymers represent an interesting option to combine properties; in this manner, polypropylene and chitosan extruded films using a different proportion of components and polypropylene-graft-maleic anhydride (PPgMA) as compatibilizer were prepared. The effect of the content of the biopolymer in the polypropylene (PP) matrix, the addition of compatibilizer, and the particle size on the properties of the composites was analyzed using characterization by fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile strength, and contact angle, finding that in general, the addition of the compatibilizer and reducing the particle size of the chitosan, favored the physicochemical and morphological properties of the films. PMID:28772464

  2. Chitosan: poly(N-vinylpyrrolidone-alt-itaconic anhydride) nanocapsules—a promising alternative for the lung cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Raţă, Delia Mihaela, E-mail: iureadeliamihaela@yahoo.com [„Apollonia” University of Iasi, Faculty of Medical Dentistry, „Academician Ioan Haulică” Research Institute (Romania); Chailan, Jean-François, E-mail: chailan@univ-tln.fr [University of Sud Toulon-Var, « Matériaux-Polymères-Interfaces-Environnement Marin (MAPIEM) Laboratory (France); Peptu, Cătălina Anişoara, E-mail: catipeptu@yahoo.co.uk [“Gheorghe Asachi” Technical University of Iasi, Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environmental Protection (Romania); Costuleanu, Marcel, E-mail: mcostuleanu@yahoo.com [University of Medicine and Pharmacy “Grigore T. Popa”- Iaşi, Department of General Pathology, Faculty of Dental Medicine (Romania); Popa, Marcel, E-mail: marpopa2001@yahoo.fr [“Gheorghe Asachi” Technical University of Iasi, Department of Natural and Synthetic Polymers, Faculty of Chemical Engineering and Environmental Protection (Romania)

    2015-07-15

    This study reports the preparation of novel polymeric nanocapsules based on a natural polymer, chitosan and a synthetic one, poly(N-vinylpyrrolidone-alt-itaconic anhydride) [(poly(NVPAI)] using an interfacial condensation technique. The infrared spectroscopy studies confirmed the crosslinking through the presence of amide bonds, formed between the two polymers chains. The diameter of nanocapsules was found in the range of 126–214 nm and it was determined by dynamic light scattering method. Morphological characterization demonstrated their nano size, the spherical shape of the nanocapsules and the formation of hollow particles. The nanocapsules presented good swelling capacity in aqueous solutions. 5-Fluorouracil (5-FU) loading and release capacity was studied, the processes being controlled by the drug diffusion through the polymeric membrane. The obtained results were encouraging, showing that 5-FU-loaded nanocapsules had 70 % higher apoptotic effect on A549 tumour cells than the drug in free state or mixed with the nanocapsules.

  3. Novel protocol for highly efficient gas-phase chemical derivatization of surface amine groups using trifluoroacetic anhydride

    Science.gov (United States)

    Duchoslav, Jiri; Kehrer, Matthias; Hinterreiter, Andreas; Duchoslav, Vojtech; Unterweger, Christoph; Fürst, Christian; Steinberger, Roland; Stifter, David

    2018-06-01

    In the current work, chemical derivatization of amine (NH2) groups with trifluoroacetic anhydride (TFAA) as an analytical method to improve the information scope of X-ray photoelectron spectroscopy (XPS) is investigated. TFAA is known to successfully label hydroxyl (OH) groups. With the introduction of a newly developed gas-phase derivatization protocol conducted at ambient pressure and using a catalyst also NH2 groups can now efficiently be labelled with a high yield and without the formation of unwanted by-products. By establishing a comprehensive and self-consistent database of reference binding energies for XPS a promising approach for distinguishing hydroxyl from amine groups is presented. The protocol was verified on different polymers, including poly(allylamine), poly(ethyleneimine), poly(vinylalcohol) and chitosan, the latter one containing both types of addressed chemical groups.

  4. Grafting of copolymer styrene maleic anhydride on poly(ethylene terephthalate) film by chemical reaction and by plasma method

    Energy Technology Data Exchange (ETDEWEB)

    Bigan, Muriel; Bigot, Julien [Laboratoire de Chimie Organique et Macromoleculaire (UMR 8009), Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Mutel, Brigitte [Laboratoire de Genie des Procedes d' Interactions Fluides reactifs-Materiaux (UPRES-EA 3751), Batiment C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France)], E-mail: Brigitte.mutel@univ-lille1.fr; Coqueret, Xavier [Laboratoire Reactions Selectives et Applications (UMR-CNRS 6519) Universite de Reims Champagne-Ardennes, B.P. 1039, 51687 Reims Cedex 2 (France)

    2008-02-15

    This work deals with the chemical grafting of a styrene maleic anhydride copolymer on the surface of a previously hydrolyzed polyethylene terephthalate (PET) film 12 {mu}m thick via covalent bond. Two different ways are studied. The first one involves an activation of the hydrolyzed PET by the triethylamine before the grafting step. In the second one, the copolymer reacts with the 4-dimethylaminopyridine in order to form maleinyl pyridinium salt which reacts with alcohol function of the hydrolyzed PET. Characterization and quantification of the grafting are performed by Fourier transform infrared spectroscopy. Factorial experiment designs are used to optimize the process and to estimate experimental parameters effects. The opportunity to associate the chemical process to a cold remote nitrogen plasma one is also examined.

  5. Improved performance of Nb-doped vanadyl pyrophosphate, catalyst for n-butane oxidation to maleic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Pavarelli, G.; Caldarelli, A.; Cavani, F. [Bologna Univ. (Italy). Dipt. di Chimica Industriale ' Toso Montanari' ; Cortelli, C.; Luciani, S. [Polynt SpA, Scanzorosciate (Italy)

    2013-11-01

    We report here about an investigation on the role of Nb{sup 5+} when used as a promoter for vanadyl pyrophosphate, catalyst for the oxidation of n-butane to maleic anhydride. The effect of Nb was very complex, a function of both its amount and the reaction temperature used. The optimal catalytic behavior was shown for very low Nb contents, i.e., for a V/Nb atomic ratio as low as 150. The main role of Nb was that of accelerating the formation of a limited amount of {gamma}-VOPO{sub 4} on the surface of vanadyl pyrophosphate, by accelerating the oxidation of V{sup 4+} into V{sup 5+} under reaction conditions. (orig.)

  6. Chitosan: poly( N-vinylpyrrolidone- alt-itaconic anhydride) nanocapsules—a promising alternative for the lung cancer treatment

    Science.gov (United States)

    Raţă, Delia Mihaela; Chailan, Jean-François; Peptu, Cătălina Anişoara; Costuleanu, Marcel; Popa, Marcel

    2015-07-01

    This study reports the preparation of novel polymeric nanocapsules based on a natural polymer, chitosan and a synthetic one, poly( N-vinylpyrrolidone- alt-itaconic anhydride) [(poly(NVPAI)] using an interfacial condensation technique. The infrared spectroscopy studies confirmed the crosslinking through the presence of amide bonds, formed between the two polymers chains. The diameter of nanocapsules was found in the range of 126-214 nm and it was determined by dynamic light scattering method. Morphological characterization demonstrated their nano size, the spherical shape of the nanocapsules and the formation of hollow particles. The nanocapsules presented good swelling capacity in aqueous solutions. 5-Fluorouracil (5-FU) loading and release capacity was studied, the processes being controlled by the drug diffusion through the polymeric membrane. The obtained results were encouraging, showing that 5-FU-loaded nanocapsules had 70 % higher apoptotic effect on A549 tumour cells than the drug in free state or mixed with the nanocapsules.

  7. Chitosan: poly(N-vinylpyrrolidone-alt-itaconic anhydride) nanocapsules—a promising alternative for the lung cancer treatment

    International Nuclear Information System (INIS)

    Raţă, Delia Mihaela; Chailan, Jean-François; Peptu, Cătălina Anişoara; Costuleanu, Marcel; Popa, Marcel

    2015-01-01

    This study reports the preparation of novel polymeric nanocapsules based on a natural polymer, chitosan and a synthetic one, poly(N-vinylpyrrolidone-alt-itaconic anhydride) [(poly(NVPAI)] using an interfacial condensation technique. The infrared spectroscopy studies confirmed the crosslinking through the presence of amide bonds, formed between the two polymers chains. The diameter of nanocapsules was found in the range of 126–214 nm and it was determined by dynamic light scattering method. Morphological characterization demonstrated their nano size, the spherical shape of the nanocapsules and the formation of hollow particles. The nanocapsules presented good swelling capacity in aqueous solutions. 5-Fluorouracil (5-FU) loading and release capacity was studied, the processes being controlled by the drug diffusion through the polymeric membrane. The obtained results were encouraging, showing that 5-FU-loaded nanocapsules had 70 % higher apoptotic effect on A549 tumour cells than the drug in free state or mixed with the nanocapsules

  8. Acylation Modification of Antheraea pernyi Silk Fibroin Using Succinic Anhydride and Its Effects on Enzymatic Degradation Behavior

    Directory of Open Access Journals (Sweden)

    Xiufang Li

    2013-01-01

    Full Text Available The degradation rate of tissue engineering scaffolds should match the regeneration rate of new tissues. Controlling the degradation behavior of silk fibroin is an important subject for silk-based tissue engineering scaffolds. In this study, Antheraea pernyi silk fibroin was successfully modified with succinic anhydride and then characterized by zeta potential, ninhydrin method, and FTIR. In vitro, three-dimensional scaffolds prepared with modified silk fibroin were incubated in collagenase IA solution for 18 days to evaluate the impact of acylation on the degradation behavior. The results demonstrated that the degradation rate of modified silk fibroin scaffolds was more rapid than unmodified ones. The content of the β-sheet structure in silk fibroin obviously decreased after acylation, resulting in a high degradation rate. Above all, the degradation behavior of silk fibroin scaffolds could be regulated by acylation to match the requirements of various tissues regeneration.

  9. Tailoring magnetic properties of self-biased hexaferrites using an alternative copolymer of isobutylene and maleic anhydride

    Science.gov (United States)

    Wu, Chuanjian; Yu, Zhong; Sokolov, Alexander S.; Yu, Chengju; Sun, Ke; Jiang, Xiaona; Lan, Zhongwen; Harris, Vincent G.

    2018-05-01

    Discussed is a novel self-biased hexaferrite gelling system based on a nontoxic and water-soluble copolymer of isobutylene and maleic anhydride. This copolymer simultaneously acts as a dispersant and gelling agent, and recently received much attention from the ceramics community. Herein its effects on the rheological conditions throughout magnetic-field pressing, and consequently, orientation, density and magnetic properties of textured hexaferrites were investigated. Ka-band FMR linewidths were measured, and the crystalline anisotropy and porosity induced linewidth broadening were estimated according to Schlömann's theory. The copolymer allowed to reduce the friction between micron-sized magnetic particulates, resulting in higher density and degree of crystalline orientation, and lower FMR linewidth.

  10. The cure for employee malaise--motivation.

    Science.gov (United States)

    Dawson, K M; Dawson, S N

    1991-01-01

    Although working conditions, hours, pay, and advancement opportunities are better now than in the 1950s--the "golden age" of American business--today's workers are significantly less satisfied. Why? The authors believe the cause of this malaise is lack of motivation. This article examines several techniques to cure employee malaise and discusses the long-term benefits of these techniques, which include empowerment, recognition, career development, the Pygmalion effect, incentives, and rewards. By making a commitment to these motivational techniques, managers will boost the morale and enthusiasm of their employees and their organization. This motivational process is not quick and easy; developing your employees is an ongoing process.

  11. Internal water curing with Liapor aggregates

    DEFF Research Database (Denmark)

    Lura, Pietro

    2005-01-01

    Internal water curing is a very efficient way to counteract self-desiccation and autogenous shrinkage in high performance concrete, thereby reducing the likelihood of early-age cracking. This paper deals with early-age volume changes and moisture transport in lightweight aggregate concrete realized...... with wet lightweight aggregates. Lightweight aggregate concrete mixtures with different degree of saturation and different particle size of the lightweight aggregates were studied and compared to normal weight concrete. Autogenous deformations, selfinduced stresses in fully restrained conditions, elastic...

  12. HIV Infection: Advances Toward a Cure.

    Science.gov (United States)

    Douek, Daniel C

    2018-04-01

    Achieving cure of HIV infection requires eliminating all replication-competent virus from the reservoir of latently infected cells or completely inhibiting infected cells from emerging from latency. Strategies include very early use of antiretroviral therapy; hematopoietic stem cell transplantation; "shock-and-kill" approaches; immune therapy with immune checkpoint inhibitors; gene therapy, including use of CC chemokine receptor 5-modified CD4+ T cells; and broadly neutralizing antibody therapy. Success is likely to require a combination of approaches. This article summarizes a presentation by Daniel C. Douek, MD, PhD, at the IAS-USA continuing education program held in Berkeley, California, in May 2017.

  13. Curing and sociocultural separatism in South Thailand.

    Science.gov (United States)

    Golomb, L

    1985-01-01

    In much of Thailand animistic curing practices have lost ground to great tradition herbal medicine and modern scientific medicine as more people achieve literacy. Especially in urbanizing areas, Buddhist and Muslim Thais hold in the highest esteem traditional curers whose knowledge derives from patient experimentation and the study of ancient texts. However, among Malay-speaking Muslims in south Thailand, the most respected therapeutic knowledge is revelatory in nature. Southern Muslim curers are generally mystics or spirit-mediums whose direct channels of communication with the supernatural convey remedies for afflictions but also provide guidelines for maintaining sociocultural separatism.

  14. Turmeric: A condiment, cosmetic and cure

    Directory of Open Access Journals (Sweden)

    Hima Gopinath

    2018-01-01

    Full Text Available Turmeric (Curcuma longa L. is an integral part of Asian culture and cuisine. It has been used in traditional medicine since centuries. A myriad of health benefits have been attributed to it. Curcumin, the most biologically active curcuminoid in turmeric, is being investigated in pre-clinical and clinical trials for its role in disease prevention and cure. It has antioxidant, anti-inflammatory, antineoplastic, anti-proliferative and antimicrobial effects. We review the chemistry of this plant, its cultural relevance in Indian skin care, and its uses in dermatology.

  15. Cancer-meter: measure and cure.

    Science.gov (United States)

    Kashyap, Sunil Kumar; Sharma, Birendra Kumar; Banerjee, Amitabh

    2017-05-01

    This paper presents a theory and system on "Cancer-Meter'. This idea came through the statement that "cancer is curable if it is measurable". The Cancer-Meter proves that it is possible. This paper proposes the cancer-meter in two ways, theoretical and electronically, as per the measurement and treatment. By the mathematics, first part is defined but the second part is based on computer programming, electrical and electronics. Thus, the cancer-meter is a programmed-electrical-electronic device which measures and cures the cancer both.

  16. Shutter mechanism for radiation-curing

    Energy Technology Data Exchange (ETDEWEB)

    Helding, N A

    1977-09-20

    In accordance with the invention, at least one lamp, and often a plurality of lamps and the reflector associated with each lamp are arrayed along the feed path of the web, so that solvent-free, curable material on the web can be cured. Each lamp has a shutter. When the shutters are closed, each shutter is in front of its respective lamp and the open side of its respective reflector. The shutters prevent impingement of radiation upon the web. When the shutters open, each unblocks its respective lamp and reflector by moving sideways and along the web feed path, thereby permitting radiation to impinge upon the web.

  17. Polyamic Acid Nanofibers Produced by Needleless Electrospinning

    Directory of Open Access Journals (Sweden)

    Oldrich Jirsak

    2010-01-01

    Full Text Available The polyimide precursor (polyamic acid produced of 4,4′-oxydiphthalic anhydride and 4,4′-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143–470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support—namely filtration effectivity and pressure drop—were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

  18. Synthesis and Verification of Biobased Terephthalic Acid from Furfural

    Science.gov (United States)

    Tachibana, Yuya; Kimura, Saori; Kasuya, Ken-Ichi

    2015-02-01

    Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct. The dehydration of the DA adduct gave phthalic anhydride, which was converted via phthalic acid and dipotassium phthalate to TPA. The biobased carbon content of the TPA was measured by accelerator mass spectroscopy and the TPA was found to be made of 100% biobased carbon.

  19. Radiation cured coating containing glitter particles and process therefor

    International Nuclear Information System (INIS)

    Sachs, P.R.; Sears, J.W.

    1992-01-01

    Radiation curable coatings for use on a variety of substrates and curable by exposure to ionizing irradiation of ultraviolet light are well known. The use of urethane type coatings cured with ultraviolet light to provide protective wear layers for wall or floor tile is for instance described in U.S. Pat. No. 4,180,615. U.S. Pat. No. 3,918,393 describes a method for obtaining a non-glossy coating on various substrates by curing radiation sensitive material with ionizing irradiation or ultraviolet light in two stages. In this process the coating is partially cured in an oxygen-containing atmosphere and the curing is completed in an inert atmosphere. U.S. Pat. No. 4,122,225 discloses a method and apparatus for coating tile which involves the application of one coat of radiation curable material to an entire substrate followed by partial curing and the subsequent application and curing of a second coat or radiation curable material only on high areas of the substrate which are subject to greater than average wear. Use of pigment in radiation cured coatings on products such as floor covering which are subject to wear during use has presented substantial difficulties. Incorporation of pigment, especially enough pigment to make the coating opaque, makes the coating hard to cure and substantially reduces the thicknesses of coating which can be cured relative to a clear coating cured under the same conditions

  20. Curing of Thick Thermoset Composite Laminates: Multiphysics Modeling and Experiments

    Science.gov (United States)

    Anandan, S.; Dhaliwal, G. S.; Huo, Z.; Chandrashekhara, K.; Apetre, N.; Iyyer, N.

    2017-11-01

    Fiber reinforced polymer composites are used in high-performance aerospace applications as they are resistant to fatigue, corrosion free and possess high specific strength. The mechanical properties of these composite components depend on the degree of cure and residual stresses developed during the curing process. While these parameters are difficult to determine experimentally in large and complex parts, they can be simulated using numerical models in a cost-effective manner. These simulations can be used to develop cure cycles and change processing parameters to obtain high-quality parts. In the current work, a numerical model was built in Comsol MultiPhysics to simulate the cure behavior of a carbon/epoxy prepreg system (IM7/Cycom 5320-1). A thermal spike was observed in thick laminates when the recommended cure cycle was used. The cure cycle was modified to reduce the thermal spike and maintain the degree of cure at the laminate center. A parametric study was performed to evaluate the effect of air flow in the oven, post cure cycles and cure temperatures on the thermal spike and the resultant degree of cure in the laminate.

  1. Critical parameters for electron beam curing of cationic epoxies and property comparison of electron beam cured cationic epoxies versus thermal cured resins and composites

    International Nuclear Information System (INIS)

    Janke, C.J.; Norris, R.E.; Yarborough, K.; Lopata, V.J.

    1997-01-01

    Electron beam curing of composites is a nonthermal, nonautoclave curing process offering the following advantages compared to conventional thermal curing: substantially reduced manufacturing costs and curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvements in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance electron beam curing of composites. The CRADA has successfully developed hundreds of new toughened and untoughened resins, offering unlimited formulation and processing flexibility. Several patent applications have been filed for this work. Composites made from these easily processable, low shrinkage material match the performance of thermal cured composites and exhibit: low void contents comparable to autoclave cured composites (less than 1%); superb low water absorption values in the same range as cyanate esters (less than 1%); glass transition temperatures rivaling those of polyimides (greater than 390 C); mechanical properties comparable to high performance, autoclave cured composites; and excellent property retention after cryogenic and thermal cycling. These materials have been used to manufacture many composite parts using various fabrication processes including hand lay-up, tow placement, filament winding, resin transfer molding and vacuum assisted resin transfer molding

  2. Stability of α-tocotrienol and α-tocopherol in salami-type sausages and curing brine depending on nitrite and pH.

    Science.gov (United States)

    Gerling, Eva-Maria; Ternes, Waldemar

    2014-12-01

    We studied the stability of the valuable vitamer nutrients α-tocotrienol and α-tocopherol and options for their protection in salami-type sausages (blended with α-tocotrienol-rich barley oil) and curing brine. Four different sausage formulations were produced containing nitrite curing salt; nitrite curing salt and ascorbic acid (300mg/kg); nitrite curing salt and carnosic acid (45mg/kg); or sodium chloride. Initial vitamer contents (100mg/kg) did not decrease significantly during ripening and decreased only slightly during storage. Ascorbic acid and carnosic acid were found to be effective in preserving the vitamers in fresh sausages. Freeze-drying of sausages resulted in a significant loss of vitamers (97%), particularly after 14-day storage at room temperature, even in the presence of shielding gases. The vitamer content in the curing brine decreased with decreasing pH in the presence of nitrite. A nitrite concentration of 136mg/L at pH4 resulted in significant loss (90%) of the vitamers. Sufficient stability of the vitamers in salami-type sausage and curing brine can be achieved by processing, formulation, and storage conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride... its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  4. Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

    International Nuclear Information System (INIS)

    Sui, G.; Zhong, W.H.; Yang, X.P.; Yu, Y.H.

    2008-01-01

    To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites

  5. Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sui, G. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States); Zhong, W.H. [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Katie.Zhong@ndsu.edu; Yang, X.P.; Yu, Y.H. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

    2008-06-25

    To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites.

  6. Effect of Hyperbranched Polymers on Curing Behavior of UV Curable Inks in Inkjet Printing

    Directory of Open Access Journals (Sweden)

    Samane Jafarifard

    2016-07-01

    Full Text Available A high quality and high resolution printing can be rapidly created by inkjet printing technology. Inkjet printing is one of the most economic printing methods and ink waste in this technique is very low. Inkjet process provides printing on any type of substrates. The UV curable inks are special types of printing inks that have been widely used in the last decades. The use of UV curable inks is more attractive in inkjet printing technology in comparison to other methods of printing. The most important advantage of UV curable inks in this method is that they are VOC-free and compatible and have good adhesion on many types of substrates. In this research, the effect of hyperbranched polymers on the curing behavior of UV curable inks was investigated. Two types of hyperbranched polymers with hydroxyl and fatty acid chain terminal groups were used in ink formulations. The effect of hyperbranched polymers on the curing behavior of UV curable ink was investigated by real-time FTIR analysis. The results showed that the hyperbranched polymers could improve curing process by increasing the conversion rate of the third curing stage. All ink formulations containing hyperbranched polymers showed higher conversion than a neat sample. The highest conversion was 77 % for the blend containing a hyperbranched polymer with hydroxyl end groups while the neat sample showed a final conversion of 55%. UV curable inks in inkjet process containing hyperbranched polymers with hydroxyl end groups showed a higher final conversion than neat sample.

  7. Influence of curing protocol on selected properties of light-curing polymers

    DEFF Research Database (Denmark)

    Dewaele, Magali; Asmussen, Erik; Peutzfeldt, Anne

    2009-01-01

    The purpose of this study was to investigate the effect of light-curing protocol on degree of conversion (DC), volume contraction (C), elastic modulus (E), and glass transition temperature (T(g)) as measured on a model polymer. It was a further aim to correlate the measured values with each other....

  8. Dr. Hall and the work cure.

    Science.gov (United States)

    Reed, Kathlyn L

    2005-01-01

    Herbert James Hall, MD (1870-1923), was a pioneer in the systematic and organized study of occupation as therapy for persons with nervous and mental disorders that he called the "work cure." He began his work in 1904 during the early years of the Arts and Crafts Movement in the United States. His primary interest was the disorder neurasthenia, a condition with many symptoms including chronic fatigue, stress, and inability to work or perform everyday tasks. The prevailing treatment of the day was absolute bed rest known as the "rest cure." Hall believed that neurasthenia was not caused by overwork but by faulty living habits that could be corrected through an ordered life schedule and selected occupations. He identified several principles of therapy that are still used today including graded activity and energy conservation. Dr. Adolph Meyer credits Hall for organizing the ideas on the therapeutic use of occupation (Meyer, 1922). Hall also provided the name American Occupational Therapy Association for the professional organization and served as the fourth president. For his many contributions to the profession Hall deserves to be recognized as a major contributor to the development and organization of occupational therapy.

  9. Electron Beam Curing of Coil Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Morganstern, K. H. [Radiation Dynamics, Inc., Westbury, NY (United States)

    1969-12-15

    The application of electron accelerators for the rapid curing of coatings on coil processing of steel and aluminium appears to have many practical and economic advantages. This paper discusses this particular application, but in the general framework of electron beam application by industry. Although industry has investigated radiation application for two decades, there have been few applications to date. The reasons for this are discussed as well as the shift in attitude now taking place, indicating a more ready acceptance of radiation processing by industry. This shift is apparent particularly in the coatings field, where the benefits of radiation processing are quite evident. In order to pinpoint these benefits a specific coatings application - coil coating - has been chosen. A typical conventional coil coating line is discussed and compared to a line employing a radiation source. Specific engineering information on the types of electron accelerators suitable for this application; the relative economics of radiation vs. heat curing; and a number of other peripheral advantages of radiation are discussed. (author)

  10. CURE: Clean use of reactor energy

    International Nuclear Information System (INIS)

    1990-05-01

    This paper presents the results of a joint Westinghouse Hanford Company (Westinghouse Hanford)-Pacific Northwest Laboratory (PNL) study that considered the feasibility of treating radioactive waste before disposal to reduce the inventory of long-lived radionuclides, making the waste more suitable for geologic disposal. The treatment considered here is one in which waste would be chemically separated so that long-lived radionuclides can be treated using specific processes appropriate for the nuclide. The technical feasibility of enhancing repository performance by this type of treatment is considered in this report. A joint Westinghouse Hanford-PNL study group developed a concept called the Clean Use of Reactor Energy (CURE), and evaluated the potential of current technology to reduce the long-lived radionuclide content in waste from the nuclear power industry. The CURE process consists of three components: chemical separation of elements that have significant quantities of long-lived radioisotopes in the waste, exposure in a neutron flux to transmute the radioisotopes to stable nuclides, and packaging of radionuclides that cannot be transmuted easily for storage or geologic disposal. 76 refs., 32 figs., 24 tabs

  11. Out-of-Autoclave Cure Composites

    Science.gov (United States)

    Hayes, Brian S.

    2015-01-01

    As the size of aerospace composite parts exceeds that of even the largest autoclaves, the development of new out-of-autoclave processes and materials is necessary to ensure quality and performance. Many out-of-autoclave prepreg systems can produce high-quality composites initially; however, due to long layup times, the resin advancement commonly causes high void content and variations in fiber volume. Applied Poleramic, Inc. (API), developed an aerospace-grade benzoxazine matrix composite prepreg material that offers more than a year out-time at ambient conditions and provides exceptionally low void content when out-of-autoclave cured. When compared with aerospace epoxy prepreg systems, API's innovation offers significant improvements in terms of out-time at ambient temperature and the corresponding tack retention. The carbon fiber composites developed with the optimized matrix technology have significantly better mechanical performance in terms of hot-wet retention and compression when compared with aerospace epoxy matrices. These composites also offer an excellent overall balance of properties. This matrix system imparts very low cure shrinkage, low coefficient of thermal expansion, and low density when compared with most aerospace epoxy prepreg materials.

  12. Strategies for the cure of HIV infection.

    Science.gov (United States)

    Rodríguez-Muñoz, Jesús; Moreno, Santiago

    2018-03-03

    The disadvantages of the long-term administration of antiretroviral therapy as well as the huge number of affected persons have placed the cure of HIV as a primary goal of Public Health. HIV may persist in the organism by at least four mechanisms: a latently infected cellular reservoir, the persistent replication of HIV in spite of ART, anatomic sanctuaries, and the immune dysfunction. Several strategies directed against these mechanisms have been developed. With all this, a complete eradication of HIV has been achieved in a patient using the transplantation of haemopoietic stem cells that were resistant to HIV-infection, and there are examples of functional cure either spontaneously (elite controllers) or after antiretroviral therapy (post-treatment controllers). However, no strategies have been successful in reducing the reservoir size, nor in achieving constant, uniform remissions. The failure of isolated strategies makes it likely that the combination of several of them may be the future solution. Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  13. UV-Curing of Nanoparticle Reinforced Acrylates

    International Nuclear Information System (INIS)

    Bauer, F.

    2006-01-01

    Polymer reinforcement by silica and alumina nanoparticles evidently yields improved surface hardness. Single mixing of nanoparticles into an acrylate formulations, however, leads to highly viscous solutions inappropriate for coating procedures. The incompatibility of inorganic fillers and organic polymers can be avoided by surface modification providing an interface between the two dissimilar materials. For example, vinyltrimethoxysilane (VTMO) can react via hydrolysis/condensation reactions with hydroxyl groups present on the inorganic surface and should bond via the polymerisation-active vinyl group to an acrylate resin through crosslinking reactions. Grafting reactions of surface OH groups and different trialkoxysilanes were studied by thermogravimetry, infrared, and multinuclear NMR spectroscopy. The copolymeri-zation of modified nanoparticles with the acrylate matrix has been investigated by 13 C NMR spectroscopy. UV curing under nitrogen inertization revealed a lower reactivity of vinyl groups of VTMO-modified silica compared to grafted methacryloxypropyl-trimethoxysilane (MEMO) which showed complete conversion of olefinic carbons (signals at 120 - 140 ppm). Under conditions of oxygen inhibition, the effect of the kind and the concentration of photoinitiator on the photopoly-merization reaction was studied. Compared to neat polyacrylate coatings the nanocomposite materials exhibit markedly improved properties, e.g., heat, scratch, and abrasion resistance. However, a much better abrasion resistance was obtained for coatings containing both silica nano-particles and corundum microparticles. In particular cases, radiation curing with 172 nm photons generated by Xe excimer was performed to obtain structured polymer surfaces, i.e., matting of the reinforced acrylate coatings

  14. Photoacoustic monitoring of inhomogeneous curing processes in polystyrene emulsions

    International Nuclear Information System (INIS)

    Vargas-Luna, M.; Gutierrez-Juarez, G.; Rodriguez-Vizcaino, J.M.; Varela-Nsjera, J.B.; Rodriguez-Palencia, J.M.; Bernal-Alvarado, J.; Sosa, M.; Alvarado-Gil, J.J.

    2002-01-01

    The time evolution of the inhomogeneous curing process of polystyrene emulsions is studied using a variant of the conventional photoacoustic (PA) technique. The thermal effusivity, as a function of time, is determined in order to monitor the sintering process of a styrene emulsion in different steps of the manufacturing procedure. PA measurements of thermal effusivity show a sigmoidal growth as a function of time during the curing process. The parameterization of these curves permits the determination of the characteristic curing time and velocity of the process. A decreasing of the curing time and an increasing curing velocity for the final steps of the manufacturing process are observed. The feasibility of our approach and its potentiality for the characterization of other curing process are discussed. (author)

  15. Acrylic injectable and self-curing formulations for the local release of bisphosphonates in bone tissue.

    Science.gov (United States)

    Rodríguez-Lorenzo, L M; Fernández, M; Parra, J; Vázquez, B; López-Bravo, A; Román, J San

    2007-11-01

    Two bisphosphonates (BPs), namely 1-hydroxy-2-[4-aminophenyl]ethane-1,1-diphosphonic acid (APBP) and 1-hydroxy-2-[3-indolyl]ethane-1,1-diphosphonic acid (IBP), have been synthesized and incorporated to acrylic injectable and self-curing formulations. Alendronic acid monosodium trihydrated salt (ALN) containing cement was formulated as control. These systems have potential applications in low density hard tissues affected by ailments characterized by a high osteoclastic resorption, i.e. osteoporosis and osteolysis. Values of curing parameters of APBP and IBP were acceptable to obtain pastes with enough fluency to be injected through a biopsy needle into the bone cavity. Working times ranged between 8 and 15 min and maximum temperature was around 50 degrees C. Cured systems stored for a month in synthetic body fluid had compressive strengths between 90 and 96 MPa and modulus between 1.2 and 1.3 GPa, which suggest mechanical stabilization after setting and in the short time. BPs were released in PBS at an initial rate depending on the corresponding chemical structure in the order ALN > APBP > IBP to give final concentrations in PBS of 2.21, 0.44, and 0.19 mol/mL for ALN, APBP, and IBP, respectively. Cytotoxicities of bisphosphonates were evaluated, IC(50) values being in the order APBP > ALN > IBP. Absence of cytotoxicity coming from leachables of the cured systems was observed in all cases independently of the BP. An improved cell growth and proliferation for the systems loaded with APBP and IBP compared with that loaded with ALN was observed, as assessed by measuring cell adhesion and proliferation, and total DNA content.

  16. Process Formulations And Curing Conditions That Affect Saltstone Properties

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. M.; Pickenheim, B. R.; Daniel, W. E.

    2012-09-28

    The first objective of this study was to analyze saltstone fresh properties to determine the feasibility of reducing the formulation water to premix (w/p) ratio while varying the amount of extra water and admixtures used during processing at the Saltstone Production Facility (SPF). The second part of this study was to provide information for understanding the impact of curing conditions (cure temperature, relative humidity (RH)) and processing formulation on the performance properties of cured saltstone.

  17. Study of oxygen inhibition effect on radiation curing

    International Nuclear Information System (INIS)

    Xiao Bin; Yang Xuemei; Zhao Pengji; Zeng Shuqing; Jiang Bo; Zhou Yong; Huang Wei; Zhou Youyi

    1995-01-01

    Michacl addition reaction product was used in the research of oxygen inhibition effect of radiation curing. The experimental results was measured by the content of gel and percentage of double bonds. It was proved that 9% of Michacl addition product could speed up 1.2 times of the radiation curing rate at 30 kGy of EB irradiation. This kind of formulation can withstand oxygen inhibition effect obviously, so it was the foundation of application for radiation curing in atmospheric condition

  18. Separation and recovery of lead from a low concentration solution of lead(II) and zinc(II) using the hydrolysis production of poly styrene-co-maleic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xing; Su, Yibing [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou (China); Yang, Ying, E-mail: Yangying@lzu.edu.cn [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou (China); Qin, Wenwu [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Separation and recovery of Pb(II) from a solution of Pb(II) and Zn(II) was performed. Black-Right-Pointing-Pointer Pb(II) can be recovered using the hydrolysis production of poly styrene-co-maleic anhydride. Black-Right-Pointing-Pointer The adsorption capacity of the PSMA resin for Pb(II) is 641.62 mg g{sup -1}. Black-Right-Pointing-Pointer Pb(II) can be recovered through desorption of Pb-PSMA into Pb(II) ion and the solid PSMA resin. Black-Right-Pointing-Pointer The resin can be repeatedly used through desorption by an inorganic acid condition (6 M H{sub 2}SO{sub 4}). - Abstract: The Pb-Zn separation/preconcentration technique, based on the complex formation reaction of Pb(II) and Zn(II), using a copolymer poly(styrene-co-maleic anhydride) (PSMA), without adding any carrier element was developed. The effects of several experimental parameters such as solution pH, temperature and adsorption time were studied. The experimental results show that the PSMA resin-Pb equilibrium was achieved in 2 min and the Pb(II) loading capacity is up to 641.62 mg g{sup -1} in aqueous solution under optimum conditions, which is much higher than the Zn(II) loading capacity within 80 min. The adsorption test for Pb(II) indicates that PSMA can recover Pb(II) from a mixed solution of Pb(II), Zn(II) and light metals such as Ca(II) and Mg(II) with higher adsorption rate and larger selective coefficient. A further study indicates that PSMA as chelating resins recovering Pb(II) can be regenerated via mineral acid (6 M H{sub 2}SO{sub 4}). PSMA was synthesized by radical polymerization and tested as an adsorbent for the selective recovery of Pb(II). In addition, the formation procedure and structure of Pb-PSMA complex were also studied. Both the PSMA and the Pb-PSMA complex were characterized by means of FTIR spectroscopy, elemental analysis, gel permeation chromatography (GPC) and atomic absorption spectrometry (AAS).

  19. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

  20. Electron beam curing - taking good ideas to the manufacturing floor

    International Nuclear Information System (INIS)

    Saunders, C.; Lopata, V.; Barnard, J.; Stepanik, T.

    2000-01-01

    Acsion is exploiting several emerging electron beam EB applications ranging from composite curing and repair to viscose manufacturing. EB curing of composite structures offers several advantages: significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; improvements in material handling; and reduced overall manufacturing costs compared to thermal curing. The aerospace industry is developing EB technology in all of their market sectors, including military aviation and space products. Some specific products include cryogenic fuel tanks, improved canopy frames for jet aircraft, and the all-composite military aircraft. This paper discusses each of these opportunities. (author)

  1. Variable selection for mixture and promotion time cure rate models.

    Science.gov (United States)

    Masud, Abdullah; Tu, Wanzhu; Yu, Zhangsheng

    2016-11-16

    Failure-time data with cured patients are common in clinical studies. Data from these studies are typically analyzed with cure rate models. Variable selection methods have not been well developed for cure rate models. In this research, we propose two least absolute shrinkage and selection operators based methods, for variable selection in mixture and promotion time cure models with parametric or nonparametric baseline hazards. We conduct an extensive simulation study to assess the operating characteristics of the proposed methods. We illustrate the use of the methods using data from a study of childhood wheezing. © The Author(s) 2016.

  2. Accounting for Cured Patients in Cost-Effectiveness Analysis.

    Science.gov (United States)

    Othus, Megan; Bansal, Aasthaa; Koepl, Lisel; Wagner, Samuel; Ramsey, Scott

    2017-04-01

    Economic evaluations often measure an intervention effect with mean overall survival (OS). Emerging types of cancer treatments offer the possibility of being "cured" in that patients can become long-term survivors whose risk of death is the same as that of a disease-free person. Describing cured and noncured patients with one shared mean value may provide a biased assessment of a therapy with a cured proportion. The purpose of this article is to explain how to incorporate the heterogeneity from cured patients into health economic evaluation. We analyzed clinical trial data from patients with advanced melanoma treated with ipilimumab (Ipi; n = 137) versus glycoprotein 100 (gp100; n = 136) with statistical methodology for mixture cure models. Both cured and noncured patients were subject to background mortality not related to cancer. When ignoring cured proportions, we found that patients treated with Ipi had an estimated mean OS that was 8 months longer than that of patients treated with gp100. Cure model analysis showed that the cured proportion drove this difference, with 21% cured on Ipi versus 6% cured on gp100. The mean OS among the noncured cohort patients was 10 and 9 months with Ipi and gp100, respectively. The mean OS among cured patients was 26 years on both arms. When ignoring cured proportions, we found that the incremental cost-effectiveness ratio (ICER) when comparing Ipi with gp100 was $324,000/quality-adjusted life-year (QALY) (95% confidence interval $254,000-$600,000). With a mixture cure model, the ICER when comparing Ipi with gp100 was $113,000/QALY (95% confidence interval $101,000-$154,000). This analysis supports using cure modeling in health economic evaluation in advanced melanoma. When a proportion of patients may be long-term survivors, using cure models may reduce bias in OS estimates and provide more accurate estimates of health economic measures, including QALYs and ICERs. Copyright © 2017 International Society for Pharmacoeconomics

  3. Preparation of deuterated succinic acids

    Energy Technology Data Exchange (ETDEWEB)

    Tashiro, Masashi; Tsuzuki, Hirohisa; Goto, Hideyuki; Ogasahara, Shoji; Mataka, Shuntaro (Kyushu Univ., Fukuoka (Japan)); Isobe, Shin-ichiro; Yonemitsu, Tadashi (Kyushu Sangyo Univ., Fukuoka (Japan). Dept. of Industrial Chemistry)

    1991-04-01

    Succinic (2,3-{sup 2}H{sub 2})- and (2,2,3,3-{sup 2}H{sub 4})-acids were prepared from maleic anhydride and dimethyl fumarate, and acetylene dicarboxylic acid and its dimethyl ester by treatment with Cu-Al and Ni-Al alloys in 10% NaOD-D{sub 2}0 in 95% to 100% isotopic purity. The succinic {sup 2}H{sub 4} acid having high isotopic purity was also obtained on the hydrolysis of 1,2-ethanedinitrile with alkaline deuterium oxide. Based on the {sup 1}H({sup 2}H) spectra analysis of N-(o-biphenyl)(2,3-{sup 2}H{sub 2})succinimide, it was elucidated that the Raney alloy reduction with alkaline deuterium oxide proceeds stepwise. (author).

  4. Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin

    Directory of Open Access Journals (Sweden)

    H. Kimura

    2011-12-01

    Full Text Available Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin were investigated. The cure behavior of benzoxazine with cyanate ester resin was monitored by model reaction using nuclear magnetic resonance (NMR. As a result of the model reaction, the ring opening reaction of benzoxazine ring and thermal self-cyclotrimerization of cyanate ester group occurred, and then the phenolic hydoroxyl group generated by the ring opening reaction of benzoxazine ring co-reacted with cyanate ester group. The properties of the cured thermosetting resin were estimated by mechanical properties, electrical resistivity, water resistance and heat resistance. The cured thermosetting resin from benzoxazine and cyanate ester resin showed good heat resistance, high electrical resistivity and high water resistance, compared with the cured thermosetting resin from benzoxazine and epoxy resin.

  5. A comparative evaluation of effect of modern-curing lights and curing modes on conventional and novel-resin monomers

    Science.gov (United States)

    Roy, Konda Karthik; Kumar, Kanumuru Pavan; John, Gijo; Sooraparaju, Sujatha Gopal; Nujella, Surya Kumari; Sowmya, Kyatham

    2018-01-01

    Aim: The aim of this study is to compare and to evaluate effect of curing light and curing modes on the nanohybrid composite resins with conventional Bis-GMA and novel tricyclodecane (TCD) monomers. Methodology: Two nanohybrid composites, IPS empress direct and charisma diamond were used in this study. Light-emitting diode (LED)-curing unit and quartz-tungsten-halogen (QTH)-curing unit which were operated into two different modes: continuous and soft start. Based on the composite resin, curing lights, and mode of curing used, the samples were divided into 8 groups. After polymerization, the samples were stored for 48 h in complete darkness at 37°C and 100% humidity. The Vickers hardness (VK) of the surface was determined with Vickers indenter by the application of 200 g for 15 s. Three VK readings were recorded for each sample surface both on top and bottom surfaces. For all the specimens, the three hardness values for each surface were averaged and reported as a single value. The mean VK and hardness ratio were calculated. The depth of cure was assessed based on the hardness ratio. Results: Comparison of mean hardness values and hardness ratios was done using ANOVA with post hoc Tukey's test. Conclusion: Both QTH- and LED-curing units had shown the adequate depth of cure. Soft-start-curing mode in both QTH- and LED-curing lights had effectively increased microhardness than the continuous mode of curing. TCD monomer had shown higher hardness values compared with conventional Bis-GMA-containing resin. PMID:29628651

  6. Effect of curing mode on the hardness of dual-cured composite resin core build-up materials

    Directory of Open Access Journals (Sweden)

    César Augusto Galvão Arrais

    2010-06-01

    Full Text Available This study evaluated the Knoop Hardness (KHN values of two dual-cured composite resin core build-up materials and one resin cement exposed to different curing conditions. Two dual-cured core build-up composite resins (LuxaCore®-Dual, DMG; and FluoroCore®2, Dentsply Caulk, and one dual-cured resin cement (Rely X ARC, 3M ESPE were used in the present study. The composite materials were placed into a cylindrical matrix (2 mm in height and 3 mm in diameter, and the specimens thus produced were either light-activated for 40 s (Optilux 501, Demetron Kerr or were allowed to self-cure for 10 min in the dark (n = 5. All specimens were then stored in humidity at 37°C for 24 h in the dark and were subjected to KHN analysis. The results were submitted to 2-way ANOVA and Tukey's post-hoc test at a pre-set alpha of 5%. All the light-activated groups exhibited higher KHN values than the self-cured ones (p = 0.00001, regardless of product. Among the self-cured groups, both composite resin core build-up materials showed higher KHN values than the dual-cured resin cement (p = 0.00001. LuxaCore®-Dual exhibited higher KHN values than FluoroCore®2 (p = 0.00001 when they were allowed to self-cure, while no significant differences in KHN values were observed among the light-activated products. The results suggest that dual-cured composite resin core build-up materials may be more reliable than dual-cured resin cements when curing light is not available.

  7. Pumice aggregates for internal water curing

    DEFF Research Database (Denmark)

    Pietro, Lura; Bentz, Dale P.; Lange, David A.

    2004-01-01

    without pumice and mixes with 4% and 8% pumice by volume of mortar. By addition of pumice, mortars with improved strength, enhanced degree of hydration and reduced autogenous shrinkage were obtained. An important obstacle to the application of this kind of pumice for actual concrete production......A novel concept in internal curing of High Performance Concrete is based on dispersing very small, saturated lightweight aggregates (LWA) in the concrete, containing sufficient water to counteract self-desiccation. With this approach, the amount of water in the LWA can be minimized, thus...... water absorption, but they release a greater percentage of their absorbed water at the equilibrium relative humidity of practical interest in early-age concrete, above 90%. Additionally, early-age properties of mortars with different contents of saturated pumice were investigated: a reference mix...

  8. Double transfer UV-curing nanoimprint lithography

    International Nuclear Information System (INIS)

    Shen, Yiming; Yao, Lei; Li, Zhiwei; Kou, Junlong; Cui, Yushuang; Bian, Jie; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng; Li, Wen-Di; Wu, Wei

    2013-01-01

    A challenge in the fabrication of nanostructures into non-planar substrates is to form a thin, uniform resist film on non-planar surfaces. This is critical to the fabrication of nanostructures via a lithographic technique due to the subsequent pattern transfer process. Here we report a new double transfer UV-curing nanoimprint technique that can create a nanopatterned thin film with a uniform residual layer not only on flat substrates but also on highly curved surfaces. Surface relief gratings with pitches down to 200 nm are successfully imprinted on the cylindrical surface of optical fibers, and further transferred into a SiO 2 matrix using reactive ion etching (RIE), demonstrating that our technique is applicable for fabricating high-resolution nanostructures on non-planar substrates. (paper)

  9. Poly(vinyl methyl ether/maleic anhydride)-Doped PEG-PLA Nanoparticles for Oral Paclitaxel Delivery To Improve Bioadhesive Efficiency.

    Science.gov (United States)

    Wang, Qian; Li, Chan; Ren, Tianyang; Chen, Shizhu; Ye, Xiaoxia; Guo, Hongbo; He, Haibing; Zhang, Yu; Yin, Tian; Liang, Xing-Jie; Tang, Xing

    2017-10-02

    Bioadhesive nanoparticles based on poly(vinyl methyl ether/maleic anhydride) (PVMMA) and poly(ethylene glycol) methyl ether-b-poly(d,l-lactic acid) (mPEG-b-PLA) were produced by the emulsification solvent evaporation method. Paclitaxel was utilized as the model drug, with an encapsulation efficiency of up to 90.2 ± 4.0%. The nanoparticles were uniform and spherical in shape and exhibited a sustained drug release compared with Taxol. m-NPs also exhibited favorable bioadhesive efficiency at the same time. Coumarin 6 or DiR-loaded nanoparticles with/without PVMMA (C6-m-NPs/DiR-m-NPs or C6-p-NPs/DiR-p-NPs) were used for cellular uptake and intestinal adhesion experiments, respectively. C6-m-NPs were shown to enhance cellular uptake, and caveolae/lipid raft mediated endocytosis was the primary route for the uptake of the nanoparticles. Favorable bioadhesive efficiency led to prolonged retention in the intestine reflected by the fluorescence in isolated intestines ex vivo. In a ligated intestinal loops model, C6-m-NPs showed a clear advantage for transporting NPs across the mucus layer over C6-p-NPs and free C6. The apparent permeability coefficient (Papp) of PTX-m-NPs through Caco-2/HT29 monolayers was 1.3- and 1.6-fold higher than PTX-p-NPs and Taxol, respectively, which was consistent with the AUC 0-t of different PTX formulations after oral administration in rats. PTX-m-NPs also exhibited a more effective anticancer efficacy, with an IC 50 of 0.2 ± 1.4 μg/mL for A549 cell lines, further demonstrating the advantage of bioadhesive nanoparticles. The bioadhesive nanoparticles m-NPs demonstrated both mucus permeation and epithelial absorption, and thus, this bioadhesive drug delivery system has the potential to improve the bioavailability of drugs that are insoluble in the gastrointestinal environment.

  10. Resonance energy transfer from quinolinone modified polystyrene-block-poly(styrene-alt-maleic anhydride) copolymer to terbium(III) metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Výprachtický, Drahomír, E-mail: vyprachticky@imc.cas.cz [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic); Mikeš, František [New York University Polytechnic School of Engineering, Polymer Research Institute, 6 MetroTech Center, Brooklyn, NY 11201 (United States); Lokaj, Jan; Pokorná, Veronika; Cimrová, Věra [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6 (Czech Republic)

    2015-04-15

    Polystyrene-block-poly(styrene-alt-maleic anhydride) was synthesized by nitroxide mediated radical polymerization and modified with 7-amino-4-methylquinolin-2(1H)-one (I) and methanol. The formed block polymer ligand contained a quinolinone fluorophore (Ω) and carboxyl (III) or sodium carboxylate (IV) binding sites. The ligand-to-metal resonance energy transfer (RET) and ligand binding properties of [III–Tb{sup 3+}] and [IV–Tb{sup 3+}] complexes were investigated by steady-state and time-resolved luminescence spectroscopy in tetrahydrofuran/methanol and/or tetrahydrofuran/deuterated methanol mixtures and compared with those of a low-molecular-weight model ligand, i.e. the sodium salt of N-(4-methyl-2-oxo-1,2-dihydroquinolin-7-yl)succinamic acid (II). The long-lived emission intensities of Tb{sup 3+} at 490, 545, 585, and 620 nm corresponding to the {sup 5}D{sub 4}→{sup 7}F{sub 6}, {sup 5}D{sub 4}→{sup 7}F{sub 5}, {sup 5}D{sub 4}→{sup 7}F{sub 4}, and {sup 5}D{sub 4}→{sup 7}F{sub 3} transitions, respectively, were strongly increased by the addition of ligands in the order [II-Tb{sup 3+}]⪡[III-Tb{sup 3+}]<[IV-Tb{sup 3+}]. The efficiency of energy transfer (E) was evaluated from the emission intensity of the donor (Ω) in the presence or absence of the acceptor (Tb{sup 3+}) depending on the acceptor concentration and ligand neutralization. It was concluded that the macromolecular ligand structural properties (polymer coil and supramolecular structures, e.g. micelles) were responsible for the increase in RET. The time-resolved luminescence measurements revealed that the binding affinity of the ligands II, III, and IV increased in the order II

  11. Steel Protective Coating Based on Plasticized Epoxy Acrylate Formulation Cured by Electron Beam Irradiation

    International Nuclear Information System (INIS)

    Ibrahim, M.S.; Said, H.M.; Mohamed, I.M.; Mohamed, H.A.; Kandile, N.G.

    2011-01-01

    Electron beam (EB) was used to cure coatings based on epoxy acrylate oligomer (EA) and different plasticizers such as epoxidized soybean oil, glycerol and castor oil. The effect of irradiation doses (10, 25, 50 kGy) on the curing epoxy acrylate formulations containing plasticizers was studied. In the addition, the effect of the different plasticizers on the end use performance properties of epoxy acrylate coatings such as hardness, bending, adhesion, acid and alkali resistance tests were investigated. It was observed that the incorporation of castor oil in epoxy acrylate, diluted by 1,6 hexandiol diacrylate monomer (HD) with a ratio (EA 70%, HD 20%, castor oil 10%) under the dose 10 kGy improved the physical, chemical and mechanical properties of cured films than the other plasticizers. On the other hand, sunflower free fatty acids were epoxidized in-situ under well established conditions and then was subjected to react with aniline in sealed ampoules under inert atmosphere at 140 degree C. The produced adduct was added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was observed that the formula containing 0.4 gm of aniline adduct / 100 gm epoxy acrylate resin gave the best corrosion protection for carbon steel

  12. Curing behavior and thermal properties of trifunctional epoxy resin cured by 4, 4’-diaminodiphenyl sulfone

    Directory of Open Access Journals (Sweden)

    2009-08-01

    Full Text Available A novel trifunctional epoxy resin 4-(3, 3-dihydro-7-hydroxy-2, 4, 4-trimethyl-2H-1-benzopyran-2-yl-1, 3-benzenediol glycidyl (shorted as TMBPBTH-EPOXY was synthesized in our lab to improve thermal performance. Its curing behavior and performance were studied by using 4, 4′-diaminodiphenyl sulfone (DDS as hardener with the mass ratio of 100:41 of TMBPBTH-EPOXY and DDS. The curing activation energy was investigated by differential scanning calorimetry (DSC to be 64.0 kJ/mol estimated by Kissinger’s method and 68.7 kJ/mol estimated by Flynn-Wall-Ozawa method respectively. Thermogravimetric analyzer (TGA was used to investigate the thermal decomposition of cured compounds. It was found that when curing temperature was lower than 180°C, the thermal decomposition temperature increased with the rise of curing temperature and curing time. On the other hand, when the curing temperature was higher than 180°C, the thermal decomposition temperature went down instead with the increase of curing time that might be the over-crosslinking of TMBPBTH-EPOXY and DDS hardener. The glass transition temperature (Tg of cured TMBPBTH-EPOXY/DDS compound determined by dynamic mechanical thermal analysis (DMTA is 290.1°C.

  13. Electron beam curing of acrylic oligomers

    International Nuclear Information System (INIS)

    Seto, J.; Arakawa, S.; Ishimoto, C.; Miyashita, M.; Nagai, T.; Noguchi, T.; Shibata, A.

    1984-01-01

    The electron-beam curing process of acrylic oligomers, with and without γ-Fe 2 O 3 pigment filler and blended linear polymer, was investigated in terms of molecular structure and reaction mechanism. The polymerized fraction of trimethylolpropane-triacrylate (TMPTA) oligomers increases with increasing total dose, and is independent of the dose rate. Since the reaction rate is linearly dependent on the dose rate, the reaction mechanism involves monomolecular termination. The reaction rate does not depend on the number of functional groups of the oligomer at low doses, but above 0.3 Mrad the rate is slower for oligomers of higher functionality. A gel is formed more readily upon curing of a polyfunctional than a monofunctional oligomer, especially at high conversion to polymer; the resulting loss of flexibility of the polymer chains slows the reaction. Decrease of the molecular weight per functional group results in lower conversion; this is also due to the loss of chain flexibility, which is indicated as well by a higher glass-transition temperature. Modification of the acrylate oligomers with urethane results in more effective cross-linking reactions because of the more rigid molecular chains. Addition of γ-Fe 2 O 3 pigment reduces the reaction rate very little, but has the effect of providing added structural integrity, as indicated by the decrease of solvent-extractable material and the improvement of anti-abrasion properties. However, the flexibility of the coating and its adhesion to a PET base film are diminished. To increase the flexibility, linear polyvinylchloride and/or polyurethane were added to the acrylic oligomers. Final conversion to polymer was nearly 100 percent, and a higher elastic modulus and better antiabrasion properties were realized

  14. Stratospheric experiments on curing of composite materials

    Science.gov (United States)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey

    2016-07-01

    Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the stratospheric flight experiment is an investigation of the effect of the stratospheric conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the stratospheric flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to stratosphere of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  15. Nanomedicine applications towards the cure of HIV.

    Science.gov (United States)

    Lisziewicz, Julianna; Tőke, Enikő R

    2013-01-01

    Combination antiretroviral therapy (cART) successfully suppresses HIV replication. However, daily and lifelong treatment is necessary to manage patient illness because cART neither eradicates infected cells from reservoirs nor reconstitutes HIV-specific immunity that could kill infected cells. Toward the cure of HIV, different nanomedicine classes have been developed with the following disease-modifying properties: to eradicate the virus by activation of latently infected CD4+ T-cells and reservoirs flushing; to kill the infected cells in the reservoirs by boosting of HIV-specific T cells; and to prevent infection by the use of microbicides with improved epithelial penetration and drug half-life. Preclinical and clinical trials consistently demonstrated that DermaVir, the most advanced nanomedicine, induces long-lasting memory T-cell responses and reduces viral load in comparison with placebo. DermaVir and the nanomedicine pipelines have the potential to improve the health of HIV-infected people at lower costs, to decrease antiretroviral drug exposure, and to contribute to the cure of HIV/AIDS. Despite the leaps and bounds in the development of antiretroviral therapy, HIV remains a significant public health challenge. In this review, applications of nanomedicine- based technologies are discussed in the context of HIV treatment, including virus elimination by activation of latently infected CD4+ T-cells; infected cell elimination in the reservoirs by boosting HIV-specific T cells, and by preventing infection by the use of microbicides with improved epithelial penetration and drug half-life. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. The Impact of Ripening Time on Technological Quality Traits, Chemical Change and Sensory Characteristics of Dry-cured Loin

    Directory of Open Access Journals (Sweden)

    Pil Nam Seong

    2015-05-01

    Full Text Available The effect of ripening time on the technological quality traits, fatty acid compositions and sensory characteristics of dry-cured loin was studied. Pork loins (n = 102 at 24 h post-mortem were used to produce dry-cured loins. The dry-cured loins were assessed at 30, 60, and 90 days of ripening for the aforementioned characteristics. Our results showed that the water activity (aw decreased (p<0.05 up to 60 days and did not change thereafter. The lipid oxidation and weight loss levels significantly (p<0.05 increased with increased ripening time. The Commission Internationale de l’Eclairage (CIE L* decreased for 90 days while CIE a* increased for 60 days and did not increase thereafter. More noticeably, the levels of most of unsaturated fatty acids and total polyunsaturated fatty acids significantly decreased as increasing ripening time up to 90 days. The 30 days-ripened loins had lower (p<0.05 color, flavor and overall acceptability scores than the loins ripened for 60 and 90 days, however, no differences in sensory traits occurred between the 60 and 90 day-ripened samples. Based on the results obtained in the present study, it is suggested that the ripening duration between 30 and 60 days could be more appropriate for producing dry-cured loin product with higher quality and economic benefits.

  17. Flame Retardance and Physical Properties of Novel Cured Blends of Unsaturated Polyester and Furan Resins

    Directory of Open Access Journals (Sweden)

    Baljinder Kaur Kandola

    2015-02-01

    Full Text Available Novel blends of two furan resins with an unsaturated polyester have been prepared and cured by parallel free radical (for the unsaturated polyester and acid-catalysed crosslinking (for the furan resin to give co-cured composite materials. Although these materials have inferior physical properties, such as low Tg and low storage modulus compared with those of unsaturated polyester and furan resins alone, they show markedly improved flame retardance compared with that of the normally highly flammable unsaturated polyester. This increased flame retardance arises from a condensed phase mechanism in which the furanic component forms a semi-protective char, reducing rates of thermal degradation and total heat release and heat of combustion. The blends also burn with reduced smoke output compared with that from unsaturated polyester alone.

  18. synthesis, antimicrobial and phytotoxic activity of amide derivatives of L-(+)-2,3-diacetoxy-4-methoxy-4-oxo-butanoic acid

    International Nuclear Information System (INIS)

    Malik, M.; Khan, S.W.; Zaidi, J.H.; Khan, K.M.; Hussain, S.

    2014-01-01

    A short, versatile, an efficient asymmetric synthesis of substituted aromatic amides is described. L-Tartaric acid conveniently converted into diacetyl-L-tartaric anhydride. Diacetyl-L-tartaric anhydride was then transformed into half ester which was then reacted with substituted anilines to yield respective chiral amides 3-8. These chiral amides were characterized by spectroscopic techniques i.e. 1H-NMR, 13C-NMR, IR and mass spectrometry. Amides 3-8 were tested for their antimicrobial as well as phytotoxic activities. (author)

  19. Radiation curing of intelligent coating for controlled release and permeation

    International Nuclear Information System (INIS)

    Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao; Sakata, Shoei; Tougou, Kazuhide; Hara, Takamichi; Matsubara, Yoshio

    2002-01-01

    Intelligent membranes for pH and temperature-responsive drug releases were developed by coating and curing of polymer-drug composite film with electrolyte or N-isopropyl acrylamide curable mixture. It was proved that those intelligent membranes showed the stimule-sensitive and responsive release functions and could be produced efficiently by radiation curing processing with a conveyer system

  20. Free radical and thermal curing of terpyridine-modified terpolymers

    NARCIS (Netherlands)

    Hofmeier, H.; El-Ghayoury, A.; Schubert, U.S.

    2004-01-01

    Terpolymers bearing terpyridine as well as (meth)acrylates as free radical curable groups (UV-curing) or hydroxyl groups (thermal curing with bis-isocyanates) were synthesized and characterized using 1H NMR, IR and UV-vis spectroscopy as well as GPC. Subsequently, the ability of covalent

  1. The statistics of dose/cure relationships for irradiated tumours

    International Nuclear Information System (INIS)

    Porter, E.H.

    1980-01-01

    Consideration is given to the theoretical effects of different factors on the form of dose/cure relationships. Single-clonogen recurrences, dominant anoxic fractions, asymptotically straight survival curves, variable tumour sizes and variable radiation doses are all discussed. Statistical methods are then reviewed, and the conclusions are summarized in the form of advice to experimenters who are studying dose/cure relationships. (UK)

  2. Influence of site curing on bond properties of reinforced lightweight ...

    African Journals Online (AJOL)

    ... the requirements for structural lightweight concrete. The developed compressive strength and pull-out strength under both site curing conditions were relatively lower than full water curing condition but still were higher than minimum requirement as per standard. Journal of Civil Engineering Research and Practice Vol.

  3. Are we eliminating cures with antibiotic abuse? A study among ...

    African Journals Online (AJOL)

    Context: The theme of “World Health Day 2011” is “combat drug resistance- No action today, No cure tomorrow” which is very pertinent. The present study emphatically demonstrates the current issues related to the overwhelming concerns regarding indiscriminate use of antibiotics, leading to a bleak tomorrow where cures ...

  4. 7 CFR 29.1019 - Flue-cured.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Flue-cured. 29.1019 Section 29.1019 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... tobacco; or tobacco cured by some other process which accomplishes the same results. [42 FR 21092, Apr. 25...

  5. 7 CFR 29.3002 - Air-cured.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-cured tobacco should not carry the odor of smoke or fumes resulting from the application of artificial...

  6. Preparation of temperature responsive fragrance release membranes by UV curing

    International Nuclear Information System (INIS)

    Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao; Okuda, Jyunya; Kitami, Toshiaki; Matsubara, Yoshio

    2003-01-01

    The authors have studied the preparation and the function of intelligent drug release membranes by UV curing. Temperature responsive fragrance release membranes were prepared by UV curing process and the release functions were investigated as the function of thickness and composition of membrane. Microscopic observations were used to prove the postulated release mechanism

  7. effect of light intensity on the cure characteristics of photo

    African Journals Online (AJOL)

    2012-05-05

    May 5, 2012 ... Objective: To determine the light intensity emitted by light curing units (LCUs) and its effect on the cure characteristics of ... of carbon-carbon double bonds conversion (11-13). Additionally, the light intensity output of a ... increases within the unit and in the restoration. This heat not only contributes to the ...

  8. Effect of Light Curing Unit Characteristics on Light Intensity Output ...

    African Journals Online (AJOL)

    Background: Modern dental composite restorations are wholly dependent on the use of Visible Light Curing devices. The characteristics of these devices may influence the quality of composite resin restorations. Objective: To determine the characteristics of light curing units (LCUs) in dental clinics in Nairobi and their effect ...

  9. Electron curing for high speed paper, film and foil converting

    International Nuclear Information System (INIS)

    Nablo, S.V.; Tripp, E.P.

    1979-01-01

    The status of self-shielded, compact electron processors for flexible web converting applications is reviewed. The uses of these units for a variety of laminating applications are described, with emphasis on the application techniques appropriate for low weight, (1 to 2 gm/m 2 ) 100% convertible adhesives. Performance data for electron cured adhesives with polyester/polyethylene systems is presented and compared with conventional urethane systems. The unique surface features of electron cured gravure coatings applied and cured at high speed are discussed, with reference to both paper and film substrates. An important advantage of electron curing of buried adhesive layers is the process quality control permitted by this 'all-electric' system. The performance characteristics of curing atmosphere control (inerting) for coatings are reviewed. Industrial experience with these processors has shown that effective inerting of coated flexible webs at speeds to 250 m/minute is both practical and economical. (author)

  10. Tailoring the morphology and properties of poly(lactic acid)/poly(ethylene-co-vinyl acetate)/starch blends via reactive compatibilization

    NARCIS (Netherlands)

    Ma, P.; Hristova - Bogaerds, D.G.; Schmit, P.; Goossens, J.G.P.; Lemstra, P.J.

    2012-01-01

    Poly(lactic acid)/poly(ethylene-co-vinyl acetate)/starch (PLA/EVA/starch) ternary blends were prepared by multi-step melt processing (reactive extrusion) in the presence of maleic anhydride (MA), benzoyl peroxide and glycerol. The effects of MA and glycerol concentration on the morphology and

  11. Effect of hydrostatic pressure, temperature, and solvent on the rate of the Diels-Alder reaction between 9,10-anthracenedimethanol and maleic anhydride

    Science.gov (United States)

    Kiselev, V. D.; Kornilov, D. A.; Anikin, O. V.; Latypova, L. I.; Konovalov, A. I.

    2017-03-01

    The rate of the reaction between 9,10-anthracenedimethanol and maleic anhydride in 1,4-dioxane, acetonitrile, trichloromethane, and toluene is studied at 25, 35, 45°C in the pressure range of 1-1772 bar. The rate constants, enthalpies, entropies and activation volumes are determined. It is shown that the rate of reaction with 9,10-anthracenedimethanol is approximately one order of magnitude higher than with 9-anthracenemethanol.

  12. Partial oxidation of Raffinate II and other mixtures of n-Butane and n-Butenes to maleic anhydride in a fixed-bed reactor

    OpenAIRE

    Brandstädter, Willi Michael

    2008-01-01

    The utilisation of the C4 streams of steamcrackers by converting raffinate II to maleic anhydride was studied. The oxidation reactions were investigated in a laboratory-scale fixed-bed reactor to determine reaction kinetics. The effects of pore diffusional resistance were investigated and explained. A two-dimensional pseudo-homogeneous reactor model was used for the simulation of a production-scale fixed-bed reactor. A flow scheme of the reactor section including a recycle was proposed.

  13. Bulk-Fill Composites: Effectiveness of Cure With Poly- and Monowave Curing Lights and Modes.

    Science.gov (United States)

    Gan, J K; Yap, A U; Cheong, J W; Arista, N; Tan, Cbk

    This study compared the effectiveness of cure of bulk-fill composites using polywave light-emitting diode (LED; with various curing modes), monowave LED, and conventional halogen curing lights. The bulk-fill composites evaluated were Tetric N-Ceram bulk-fill (TNC), which contained a novel germanium photoinitiator (Ivocerin), and Smart Dentin Replacement (SDR). The composites were placed into black polyvinyl molds with cylindrical recesses of 4-mm height and 3-mm diameter and photopolymerized as follows: Bluephase N Polywave High (NH), 1200 mW/cm 2 (10 seconds); Bluephase N Polywave Low (NL), 650 mW/cm 2 (18.5 seconds); Bluephase N Polywave soft-start (NS), 0-650 mW/cm 2 (5 seconds) → 1200 mW/cm 2 (10 seconds); Bluephase N Monowave (NM), 800 mW/cm 2 (15 seconds); QHL75 (QH), 550 mW/cm 2 (21.8 seconds). Total energy output was fixed at 12,000 mJ/cm 2 for all lights/modes, with the exception of NS. The cured specimens were stored in a light-proof container at 37°C for 24 hours, and hardness (Knoop Hardness Number) of the top and bottom surfaces of the specimens was determined using a Knoop microhardness tester (n=6). Hardness data and bottom-to-top hardness ratios were subjected to statistical analysis using one-way analysis of variance/Scheffe's post hoc test at a significance level of 0.05. Hardness ratios ranged from 38.43% ± 5.19% to 49.25% ± 6.38% for TNC and 50.67% ± 1.54% to 67.62% ± 6.96% for SDR. For both bulk-fill composites, the highest hardness ratios were obtained with NM and lowest hardness ratios with NL. While no significant difference in hardness ratios was observed between curing lights/modes for TNC, the hardness ratio obtained with NM was significantly higher than the hardness ratio obtained for NL for SDR.

  14. Sensory quality, colour and oxidative stability of cured cooked ham with propolis extract

    Directory of Open Access Journals (Sweden)

    Miroslav Kročko

    2014-02-01

    Full Text Available The effect of 0.06% propolis ethanol extract on the sensory quality, colour and oxidative stability of cured cooked ham was evaluated. Half of the experimentally processed hams treated with 0.06% ethanolic extract of propolis with ascorbic acid (EEP, only with ascorbic acid (AA and control samples (C were sliced and vacuum packaged. Samples were kept at 4 °C 21 days (sliced respectively 20, 50 and 100 days (unsliced. The results revealed that all samples were characterized without any significant colour discrepancies. In general, the thiobarbituric acid value (mg malondialdehyde/kg increased gradually in all samples examined, with a significantly lower (P <0.05 level for treated samples than for controls. The significantly lowest (P <0.05 sensory parameters in comparison to unsliced hams were observed in sliced hams packaged in vacuum. Sliced hams with EEP were characterized with significantly lowest (P <0.05 intensity of characteristic aroma. Undesirable taste was detected in control sliced hams after storage period. Significantly (P <0.05 more desirable taste of sliced hams was observed in those with only ascorbic acid in comparison with EEP. In our study was demonstrated that 0.06% ethanol extract of propolis positive affected oxidation stability and not negative affected others technological (pH, colour and sensory characteristics of poultry meat product - cured cooked ham. Normal 0 21 false false false CS JA X-NONE

  15. Proceedings of national executive management seminar on surface finishing by radiation curing technology: radiation curing for better finishing

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    This book compiled the paper presented at this seminar. The papers discussed are 1. Incentives for investment in the manufacturing sector (in Malaysia) 2.Trends and prospect of surface finishing by radiation curing technology in Malaysia 3. Industrial application of radiation curing.

  16. Proceedings of national executive management seminar on surface finishing by radiation curing technology: radiation curing for better finishing

    International Nuclear Information System (INIS)

    1993-01-01

    This book compiled the paper presented at this seminar. The papers discussed are 1. Incentives for investment in the manufacturing sector (in Malaysia) 2.Trends and prospect of surface finishing by radiation curing technology in Malaysia 3. Industrial application of radiation curing

  17. MICROBIOLOGICAL EVOLUTION OF DACIA SAUSAGE, A DRY CURED ROMANIAN SAUSAGE

    Directory of Open Access Journals (Sweden)

    Ana Maria Simion Ciuciu

    2011-09-01

    Full Text Available Selected starter cultures were used to produce the traditional Romanian dry cured sausage, Dacia. A control sausage was produced without starter culture (sausage A, one with L. sakei CECT 5964 and S. equorum SA25 (sausage B and one with L. sakei CECT 5964, S. equorum SA25 and L. acidophilus CECT 903 (sausage C. Samples from each batch of sausages were taken at 0 (mix before stuffing, and after 2, 4, 7, 14, 21 and 28 days of ripening. Counts of total aerobic mesophilic flora, lactic acid bacteria, salt tolerant flora, and Enterobacteriaceae and some physical-chemical parameters (moisture, NaCl, pH and aw values were determined. High microbial counts (log CFU were observed with values at the end of ripening period: for lactic acid bacteria 9.77 (A, 11.47 (B and 11.19 (C; for total aerobic mesophilic flora 9.89 (A, 11.38 (B and 11.30 (C; for salt tolerant flora 4.45 (A, 5.31 (B and 5.27 (C. The starter cultures had a significant inhibitory effect on Enterobacteriaceae counts (log CFU, values at the end of ripening period being 1.32 (A, 0.33 (B and not detected (C. A significant decrease in the pH values is observed until the seventh day of ripening, showing a slight, but progressive increase after the 14th day of ripening. Results show that the production and ripening process in a pilot scale chamber under controlled conditions contributes in obtaining safe and homogeneous products.

  18. Separation and recovery of lead from a low concentration solution of lead(II) and zinc(II) using the hydrolysis production of poly styrene-co-maleic anhydride.

    Science.gov (United States)

    Liang, Xing; Su, Yibing; Yang, Ying; Qin, Wenwu

    2012-02-15

    The PbZn separation/preconcentration technique, based on the complex formation reaction of Pb(II) and Zn(II), using a copolymer poly(styrene-co-maleic anhydride) (PSMA), without adding any carrier element was developed. The effects of several experimental parameters such as solution pH, temperature and adsorption time were studied. The experimental results show that the PSMA resin-Pb equilibrium was achieved in 2 min and the Pb(II) loading capacity is up to 641.62 mg g(-1) in aqueous solution under optimum conditions, which is much higher than the Zn(II) loading capacity within 80 min. The adsorption test for Pb(II) indicates that PSMA can recover Pb(II) from a mixed solution of Pb(II), Zn(II) and light metals such as Ca(II) and Mg(II) with higher adsorption rate and larger selective coefficient. A further study indicates that PSMA as chelating resins recovering Pb(II) can be regenerated via mineral acid (6M H(2)SO(4)). PSMA was synthesized by radical polymerization and tested as an adsorbent for the selective recovery of Pb(II). In addition, the formation procedure and structure of Pb-PSMA complex were also studied. Both the PSMA and the Pb-PSMA complex were characterized by means of FTIR spectroscopy, elemental analysis, gel permeation chromatography (GPC) and atomic absorption spectrometry (AAS). Copyright © 2011 Elsevier B.V. All rights reserved.

  19. The role of different nonspecific interactions and halogen contacts in the crystal structure organization of 5-chloroisatoic anhydride.

    Science.gov (United States)

    Pogoda, Dorota; Matera-Witkiewicz, Agnieszka; Listowski, Marcin; Janczak, Jan; Videnova-Adrabinska, Veneta

    2018-03-01

    The crystal structure of 6-chloro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione (5-chloroisatoic anhydride), C 8 H 4 ClNO 3 , has been determined and analysed in terms of connectivity and packing patterns. The compound crystallizes in the noncentrosymmetric space group Pna2 1 with one molecule in the asymmetric unit. The role of different weak interactions is discussed with respect to three-dimensional network organization. Molecules are extended into one-dimensional helical arrangements, making use of N-H...O hydrogen bonds and π-π interactions. The helices are further organized into monolayers via weak C-H...O and lone pair-π interactions, and the monolayers are packed into a noncentrosymmetric three-dimensional architecture by C-Cl...π interactions and C-H...Cl and Cl...Cl contacts. A Hirshfeld surface (HS) analysis was carried out and two-dimensional (2D) fingerprint plots were generated to visualize the intermolecular interactions and to provide quantitative data for their relative contributions. In addition, tests of the antimicrobial activity and in vitro cytotoxity effects against fitoblast L929 were performed and are discussed.

  20. Using monosaccharide anhydrides to estimate the impact of wood combustion on fine particles in the Helsinki Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Saarnio, K.; Saarikoski, S. [Finnish Meteorological Institute, Helsinki (Finland); Niemi, J.V. [HSY Helsinki Region Environmental Services Authority, Helsinki (Finland)

    2012-11-01

    The spatiotemporal variation of ambient particles under the influence of biomass burning emissions was studied in the Helsinki Metropolitan Area (HMA) in selected periods during 2005-2009. Monosaccharide anhydrides (MAs; levoglucosan, mannosan and galactosan), commonly known biomass burning tracers, were used to estimate the wood combustion contribution to local particulate matter (PM) concentration levels at three urban background sites close to the city centre, and at three suburban sites influenced by local small-scale wood combustion. In the cold season (October-March), the mean MAs concentrations were 115-225 ng m{sup -3} and 83-98 ng m{sup -} {sup 3}at the suburban and urban sites, respectively. In the warm season, the mean MAs concentrations were low (19-78 ng m{sup -3}), excluding open land fire smoke episodes (222-378 ng m{sup -}3{sup )}. Regionally distributed wood combustion particles raised the levels over the whole HMA while particles from local wood combustion sources raised the level at suburban sites only. The estimated average contribution of wood combustion to fine particles (PM{sub 2.5}) ranged from 18% to 29% at the urban sites and from 31% to 66% at the suburban sites in the cold season. The PM measurements from ambient air and combustion experiments showed that the proportions of the three MAs can be utilised to separate the wildfire particles from residential wood combustion particles. (orig.)

  1. Adsorption of heavy metal ions and azo dyes by crosslinked nanochelating resins based on poly(methylmethacrylate-co-maleic anhydride

    Directory of Open Access Journals (Sweden)

    M. Ghaemy

    2014-03-01

    Full Text Available Chelating resins are suitable materials for the removal of heavy metals in water treatments. A copolymer, Poly(MMA-co-MA, was synthesized by radical polymerization of maleic anhydride (MA and methyl methacrylate (MMA, characterized and transformed into multifunctional nanochelating resin beads (80–150 nm via hydrolysis, grafting and crosslink reactions. The resin beads were characterized by swelling studies, field emission scanning electron microscopy (FESEM and Fourier transform infrared spectroscopy (FTIR. The main purpose of this work was to determine the adsorption capacity of the prepared resins (swelling ratio ~55% towards metal ions such as Hg2+, Cd2+, Cu2+ from water at three different pH values (3, 6 and 9. Variations in pH and types of metal ions have not significantly affected the chelation capacity of these resins. The maximum chelation capacity of one of the prepared resin beads (Co-g-AP3 for Hg2+ was 63, 85.8 and 71.14 mg/g at pH 3, 6 and 9, respectively. Approximately 96% of the metal ions could be desorbed from the resin. Adsorption capacity of these resins towards three commercial synthetic azo dyes was also investigated. The maximum adsorption of dye AY42 was 91% for the resin Co-g-AP3 at room temperature. This insures the applicability of the synthesized resins for industrial applications.

  2. Optimal oxygen feeding policy to maximize the production of Maleic anhydride in unsteady state fixed bed catalytic reactors

    Directory of Open Access Journals (Sweden)

    E. Ali

    2017-07-01

    Full Text Available The effect of different oxygen feeding scenarios in a fixed bed reactor for the production of Maleic anhydride (MA is studied. Two reactor configurations were examined. In the first configuration, a cross flow reactor (CFR with 4 discrete feeding points is considered. Another configuration is the conventional packed-bed reactor (PBR with a single feed. Nonlinear Model Predictive Controller (NLMPC was used as optimal controller to operate the CFR in dynamic mode and to optimize the multiple feed dosages in order to enhance the MA yield. The simulation results indicated that different combinations of the four feed ratios can operate the reactor at the best value for the yield provided the first feeding point is kept as low as possible. For the packed bed reactor configuration, a single oxygen feed is considered and is optimized transiently by NLMPC. The simulation outcomes showed that the reactor performance in terms of the produced MA mole fraction can also be enhanced to the same magnitude obtained by CFR configuration. This improvement requires decreasing the oxygen ratio in the reactor single feed by 70%.

  3. Effect of Surface Modification of Palygorskite on the Properties of Polypropylene/Polypropylene-g-Maleic Anhydride/Palygorskite Nanocomposites

    Directory of Open Access Journals (Sweden)

    David Cisneros-Rosado

    2017-01-01

    Full Text Available The effect of surface modification of palygorskite (Pal on filler dispersion and on the mechanical and thermal properties of polypropylene (PP/polypropylene grafted maleic anhydride (PP-g-MAH/palygorskite (Pal nanocomposites was evaluated. A natural Pal mineral was purified and individually surface modified with hexadecyl tributyl phosphonium bromide and (3-Aminopropyltrimethoxysilane; the pristine and modified Pals were melt-compounded with PP to produce nanocomposites using PP-g-MAH as compatibilizer. The grafting of Pal surface was verified by FT-IR and the change in surface hydrophilicity was estimated by the contact angle of sessile drops of ethylene glycol on Pal tablets. The extent of Pal dispersion and the degree of improvement in both the mechanical and thermal properties were related to the surface treatment of Pal. Modified Pals were better dispersed during melt processing and improved Young’s modulus and strength; however, maximum deformation tended to decrease. The thermal stability of PP/PP-g-MAH/Pal nanocomposites was considerably improved with the content of modified Pals. The degree of crystallinity increased with Pal content, regardless of the surface modification. Surfactant modified Pal exhibited better results in comparison with silane Pal; it is possible that longer alkyl chains from surfactant molecules promoted interactions with polymer chains, thereby improving nanofiller dispersion and enhancing the properties.

  4. Separator Membrane from Crosslinked Poly(Vinyl Alcohol and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride

    Directory of Open Access Journals (Sweden)

    Charu Vashisth Rohatgi

    2015-03-01

    Full Text Available In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride (PMVE-MA. Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity, thermal and electrochemical properties using differential scanning calorimetry (DSC, dynamic mechanical analysis (DMA, thermo-gravimetric analysis (TGA and electrochemical impedance spectroscopy (EIS. The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications.

  5. Insight into the informational-structure behavior of the Diels-Alder reaction of cyclopentadiene and maleic anhydride.

    Science.gov (United States)

    Molina-Espíritu, Moyocoyani; Esquivel, Rodolfo O; Kohout, Miroslav; Angulo, Juan Carlos; Dobado, José A; Dehesa, Jesús S; LópezRosa, Sheila; Soriano-Correa, Catalina

    2014-08-01

    The course of the Diels-Alder reactions of cyclopentadiene and maleic anhydride were studied. Two reaction paths were modelled: endo- and exo-selective paths. All structures within the transient region were characterized and analyzed by means of geometrical descriptors, physicochemical parameters and information-theoretical measures in order to observe the linkage between chemical behavior and the carriage of information. We have shown that the information-theoretical characterization of the chemical course of the reaction is in complete agreement with its phenomenological behavior in passing from reactants to products. In addition, we were able to detect the main differences between the two reaction mechanisms. This type of informational analysis serves to provide tools to help understand the chemical reactivity of the two simplest Diels-Alder reactions, which permits the establishment of a connection between the quantum changes that molecular systems exert along reaction coordinates and standard physicochemical phenomenology. In the present study, we have shown that every reaction stage has a family of subsequent structures that are characterized not solely by their phenomenological behavior but also by informational properties of their electronic density distribution (localizability, order, uniformity). Moreover, we were able to describe the main differences between endo-adduct and exo-adduct pathways. With the advent of new experimental techniques, it is in principle possible to observe the structural changes in the transient regions of chemical reactions. Indeed, through this work we have provided the theoretical concepts needed to unveil the concurrent processes associated with chemical reactions.

  6. Separator Membrane from Crosslinked Poly(Vinyl Alcohol) and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride)

    Science.gov (United States)

    Rohatgi, Charu Vashisth; Dutta, Naba K.; Choudhury, Namita Roy

    2015-01-01

    In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity), thermal and electrochemical properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications. PMID:28347019

  7. Preparation of High Density Polyethylene/Waste Polyurethane Blends Compatibilized with Polyethylene-Graft-Maleic Anhydride by Radiation

    Directory of Open Access Journals (Sweden)

    Jong-Seok Park

    2015-04-01

    Full Text Available Polyurethane (PU is a very popular polymer that is used in a variety of applications due to its good mechanical, thermal, and chemical properties. However, PU recycling has received significant attention due to environmental issues. In this study, we developed a recycling method for waste PU that utilizes the radiation grafting technique. Grafting of waste PU was carried out using a radiation technique with polyethylene-graft-maleic anhydride (PE-g-MA. The PE-g-MA-grafted PU/high density polyethylene (HDPE composite was prepared by melt-blending at various concentrations (0–10 phr of PE-g-MA-grafted PU. The composites were characterized using fourier transform infrared spectroscopy (FT-IR, and their surface morphology and thermal/mechanical properties are reported. For 1 phr PU, the PU could be easily introduced to the HDPE during the melt processing in the blender after the radiation-induced grafting of PU with PE-g-MA. PE-g-MA was easily reacted with PU according to the increasing radiation dose and was located at the interface between the PU and the HDPE during the melt processing in the blender, which improved the interfacial interactions and the mechanical properties of the resultant composites. However, the elongation at break for a PU content >2 phr was drastically decreased.

  8. Intranasal Administration of Maleic Anhydride-Modified Human Serum Albumin for Pre-Exposure Prophylaxis of Respiratory Syncytial Virus Infection

    Directory of Open Access Journals (Sweden)

    Zhiwu Sun

    2015-02-01

    Full Text Available Respiratory syncytial virus (RSV is the leading cause of pediatric viral respiratory tract infections. Neither vaccine nor effective antiviral therapy is available to prevent and treat RSV infection. Palivizumab, a humanized monoclonal antibody, is the only product approved to prevent serious RSV infection, but its high cost is prohibitive in low-income countries. Here, we aimed to identify an effective, safe, and affordable antiviral agent for pre-exposure prophylaxis (PrEP of RSV infection in children at high risk. We found that maleic anhydride (ML-modified human serum albumin (HSA, designated ML-HSA, exhibited potent antiviral activity against RSV and that the percentages of the modified lysines and arginies in ML- are correlated with such anti-RSV activity. ML-HSA inhibited RSV entry and replication by interacting with viral G protein and blocking RSV attachment to the target cells, while ML-HAS neither bound to F protein, nor inhibited F protein-mediated membrane fusion. Intranasal administration of ML-HSA before RSV infection resulted in significant decrease of the viral titers in the lungs of mice. ML-HSA shows promise for further development into an effective, safe, affordable, and easy-to-use intranasal regimen for pre-exposure prophylaxis of RSV infection in children at high risk in both low- and high-income countries.

  9. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Godoy-Gallardo, Maria, E-mail: maria.godoy.gallardo@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Guillem-Marti, Jordi, E-mail: jordi.guillem.marti@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Sevilla, Pablo, E-mail: psevilla@euss.es [Department of Mechanics, Escola Universitària Salesiana de Sarrià (EUSS), C/ Passeig de Sant Bosco, 42, 08017 Barcelona (Spain); Manero, José M., E-mail: jose.maria.manero@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Gil, Francisco J., E-mail: francesc.xavier.gil@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); and others

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  10. Preparation of a Sepia Melanin and Poly(ethylene-alt-maleic Anhydride Hybrid Material as an Adsorbent for Water Purification

    Directory of Open Access Journals (Sweden)

    Guido Panzarasa

    2018-01-01

    Full Text Available Meeting the increasing demand of clean water requires the development of novel efficient adsorbent materials for the removal of organic pollutants. In this context the use of natural, renewable sources is of special relevance and sepia melanin, thanks to its ability to bind a variety of organic and inorganic species, has already attracted interest for water purification. Here we describe the synthesis of a material obtained by the combination of sepia melanin and poly(ethylene-alt-maleic anhydride (P(E-alt-MA. Compared to sepia melanin, the resulting hybrid displays a high and fast adsorption efficiency towards methylene blue (a common industrial dye for a wide pH range (from pH 2 to 12 and under high ionic strength conditions. It is easily recovered after use and can be reused up to three times. Given the wide availability of sepia melanin and P(E-alt-MA, the synthesis of our hybrid is simple and affordable, making it suitable for industrial water purification purposes.

  11. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    International Nuclear Information System (INIS)

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M.; Gil, Francisco J.

    2016-01-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  12. Micelles Formed by Polypeptide Containing Polymers Synthesized Via N-Carboxy Anhydrides and Their Application for Cancer Treatment

    Directory of Open Access Journals (Sweden)

    Dimitrios Skoulas

    2017-06-01

    Full Text Available The development of multifunctional polymeric materials for biological applications is mainly guided by the goal of achieving the encapsulation of pharmaceutical compounds through a self-assembly process to form nanoconstructs that control the biodistribution of the active compounds, and therefore minimize systemic side effects. Micelles are formed from amphiphilic polymers in a selective solvent. In biological applications, micelles are formed in water, and their cores are loaded with hydrophobic pharmaceutics, where they are solubilized and are usually delivered through the blood compartment. Even though a large number of polymeric materials that form nanocarrier delivery systems has been investigated, a surprisingly small subset of these technologies has demonstrated potentially curative preclinical results, and fewer have progressed towards commercialization. One of the most promising classes of polymeric materials for drug delivery applications is polypeptides, which combine the properties of the conventional polymers with the 3D structure of natural proteins, i.e., α-helices and β-sheets. In this article, the synthetic pathways followed to develop well-defined polymeric micelles based on polypeptides prepared through ring-opening polymerization (ROP of N-carboxy anhydrides are reviewed. Among these works, we focus on studies performed on micellar delivery systems to treat cancer. The review is limited to systems presented from 2000–2017.

  13. Amphiphilic graft copolymer based on poly(styrene-co-maleic anhydride) with low molecular weight polyethylenimine for efficient gene delivery

    Science.gov (United States)

    Duan, Xiaopin; Xiao, Jisheng; Yin, Qi; Zhang, Zhiwen; Mao, Shirui; Li, Yaping

    2012-01-01

    Background and methods A new amphiphilic comb-shaped copolymer (SP) was synthesized by conjugating poly(styrene-co-maleic anhydride) with low molecular weight polyethyleneimine for gene delivery. Fourier transform infrared spectrum, 1H nuclear magnetic resonance, and gel permeation chromatography were used to characterize the graft copolymer. Results The buffering capability of SP was similar to that of polyethyleneimine within the endosomal pH range. The copolymer could condense DNA effectively to form complexes with a positive charge (13–30 mV) and a small particle size (130–200 nm) at N/P ratios between 5 and 20, and protect DNA from degradation by DNase I. In addition, SP showed much lower cytotoxicity than polyethyleneimine 25,000. Importantly, the gene transfection activity and cellular uptake of SP-DNA complexes were all markedly higher than that of complexes of polyethyleneimine 25,000 and DNA in MCF-7 and MCF-7/ADR cell lines. Conclusion This work highlights the promise of SP as a safe and efficient synthetic vector for DNA delivery. PMID:23028224

  14. Synthesis and characterization of poly(vinylphosphonic acid) for proton exchange membranes in fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Bingoel, Bahar

    2007-07-01

    Vinylphosphonic acid (VPA) was polymerized at 80 C by free radical polymerization to give polymers (PVPA) of different molecular weight depending on the initiator concentration. The highest molecular weight, Mw, achieved was 6.2 x 10{sup 4} g/mol as determined by static light scattering. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to gain microstructure information about the polymer chain. Information based on tetrad probabilities was utilized to deduce an almost atactic configuration. In addition, {sup 13}CNMR gave evidence for the presence of head-head and tail-tail links. Refined analysis of the {sup 1}H NMR spectra allowed for the quantitative determination of the fraction of these links (23.5 percent of all links). Experimental evidence suggested that the polymerization proceeded via cyclopolymerization of the vinylphosphonic acid anhydride as an intermediate. Titration curves indicated that high molecular weight poly(vinylphosphonic acid) PVPA behaved as a monoprotic acid. Proton conductors with phosphonic acid moieties as protogenic groups are promising due to their high charge carrier concentration, thermal stability, and oxidation resistivity. Blends and copolymers of PVPA have already been reported, but PVPA has not been characterized sufficiently with respect to its polymer properties. Therefore, we also studied the proton conductivity behaviour of a well-characterized PVPA. PVPA is a conductor; however, the conductivity depends strongly on the water content of the material. The phosphonic acid functionality in the resulting polymer, PVPA, undergoes condensation leading to the formation of phosphonic anhydride groups at elevated temperature. Anhydride formation was found to be temperature dependent by solid state NMR. Anhydride formation affects the proton conductivity to a large extent because not only the number of charge carriers but also the mobility of the charge carriers seems to change. (orig.)

  15. [Respiratory manifestations after exposure to sulfurous anhydride in wine-cellar workers: 6 case reports].

    Science.gov (United States)

    Testud, F; Matray, D; Lambert, R; Hillion, B; Blanchet, C; Teisseire, C; Thibaudier, J M; Raoux, C; Pacheco, Y

    2000-02-01

    Sulfite treatment of wine [a process exploiting the biocidal and anti-oxidant properties of sulfur dioxide (SO2)] involves the use of liquified gas, aqueous solutions or bisulfites, i.e. the salts of sulfurous acid which slowly release SO2. This procedure can result in repeated exposures of operators to significant amounts of SO2. However, risks associated with the use of SO2 are greatly under-estimated by wine producers and wine-cellar workers. We report on 6 cases of respiratory symptoms attributable to SO2 identified during a survey of wine-cellars in the French Beaujolais district. Their pathogenesis is discussed after an overview of the occupational toxicology of SO2.

  16. Light resin curing devices - a hazard evaluation

    International Nuclear Information System (INIS)

    Glansholm, A.

    1985-09-01

    An evaluation has been made of optical hazards to the eye from 18 specified lamps designed for curing dental composite plastic fillings. Radiation source in all of the investigated units were incandescent lamps of the tungsten metal halide type. Ultraviolet and visible radiation was measured with a calibrated EGandG 585 spectroradiometer system. Tables and diagrams of spectral radiance (Wm -2 nm -1 sr -1 ) are given. Hazard evaluation based on the ACGIH Threshold Limit Values of ultraviolet and visible radiation gave the following results: 1. Ultraviolet radiation is of no concern ( -2 UVA at 10 cm). 2. Reflexes from teeth are harmless. 3. Retinal thermal injury hazard (permanent burn damage) is diminnutive and non-existent if the equipment is handled with sense (irradiation of an unprotected eye at a distance less than 10 cm should be avoided). 4. Retinal photochemical (blue-light) injury may appear after direct viewing of the end of the fiber-optics cable. A table with safe exposure time for each apparatus is given. Proper protective goggles can eliminate the blue-light hazard. (Author)

  17. Cure kinetics and chemorheology of EPDM/graphene oxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Allahbakhsh, Ahmad [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh, E-mail: s.mazinani@aut.ac.ir [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Kalaee, Mohammad Reza [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Sharif, Farhad [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2013-07-10

    Graphical abstract: - Highlights: • Graphene oxide content and dispersion as effective parameters on cure kinetics. • Graphene oxide as an effective controlling factor of crosslink density. • Interaction of graphene oxide with curing system (ZnO) during curing process. - Abstract: In this study, the effect of graphene oxide on cure behavior of ethylene–propylene–diene rubber (EPDM) nanocomposite is studied. In this regard, the cure kinetics of nanocomposite is studied employing different empirical methods. The required activation energy of nth-order cure process shows about 160 kJ/mol increments upon 5 phr graphene oxide loading compared to 1 phr graphene oxide loading. However, the required activation energy is significantly reduced followed by incorporation of graphene oxide in nanocomposites compared to neat EPDM sample. Furthermore, the effect of graphene oxide on structural properties of nanocomposites during the cure process is studied using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry techniques. As the results show, graphene oxide interestingly affects the structure of zinc oxide during the vulcanization process. This behavior could be probably related to high tendency of zinc oxide to react with oxidized surface of graphene oxide.

  18. Efficiency of light curing units in a government dental school.

    Science.gov (United States)

    Nassar, Hani M; Ajaj, Reem; Hasanain, Fatin

    2018-01-01

    The light intensity of a light-curing unit is a crucial factor that affects the clinical longevity of resin composites. This study aimed to investigate the efficiency of light-curing units in use at a local governmental dental school for curing conventional and bulk-fill resin materials. A total of 166 light-curing units at three locations were examined, and the brand, type, clinic location, diameter of curing tip, tip cleanliness (using a visual score), and the output (in mW/cm 2 using a digital radiometer) were recorded. Only 23.5% of the units examined had clean tips, with the graduate student clinical area containing the highest percentage of clean tips. Further, tips with poor cleanliness score values were associated with significantly lower output intensities. A small percentage (9.4%) of units was capable of producing intensities higher than 1,200 mW/cm 2 and lower than 600 mW/cm 2 (7.6%). The majority of the low intensity units were located in the undergraduate student area, which also contained the highest number of units with intensities between 900 and 1,200 mW/cm 2 . The output of all the units in service was satisfactory for curing conventional resin composites, and most units were capable of curing bulk-fill resin materials.

  19. Simulation of curing of a slab of rubber

    International Nuclear Information System (INIS)

    Abhilash, P.M.; Kannan, K.; Varkey, Bijo

    2010-01-01

    The objective of the present work is to predict the degree of curing for a rectangular slab of rubber, which was subjected to non-uniform thermal history. As the thermal conductivity of rubber is very low, the temperature gradient across a slab is quite large, which leads to non-uniform vulcanization, and hence non-uniform mechanical properties-an inhomogeneous material. Since curing is an exothermic reaction, heat transfer and chemical reactions are solved in a coupled manner. The effect of heat generation on curing is also discussed.

  20. Strontium binding to cement paste cured at different temperature

    International Nuclear Information System (INIS)

    Peterson, V.K.; Ray, A.

    1999-01-01

    Concentration - depth profiles were measured using Proton Induced X-ray Emission (PIXE). These results were used as a measure of the Sr 2+ retention abilities of each matrix. Ordinary Portland cement (OPC) and cemented clinoptilolite samples were cured at 25 deg C, 60 deg C and 150 deg C. As expected, the Sr 2+ penetration depth increased with increasing OPC cure temperature, caused by an increase in sample permeability. Surprisingly, the penetration depths of Sr 2+ increased with the addition of clinoptilolite to the OPC, also thought to be caused by an increase in sample permeability. However, the increase in penetration depth was reduced in samples cured at higher temperatures

  1. Comparison study of crosslink density determination in cured rubber

    International Nuclear Information System (INIS)

    El-sabbagh, S.H.; Yehia, A.A.

    2005-01-01

    The crosslink density is an important property affecting the major characteristics of cured rubber. The crosslink density can be determined by different methods such as: 1. Dynamic mechanical method using the data of stress-strain relationship. 2. Mooney-Rivlin equation 3. Swelling in organic solvents measurements using Flory-Rehner equation. The crosslink density calculated by the previous methods were discussed and compared with each other for cured NR, SBR and NBR. The obtained data showed that the dynamic-mechanical method can be considered as a simple and reliable method for determination of crosslink density for cured rubbers

  2. Simulation of curing of a slab of rubber

    Energy Technology Data Exchange (ETDEWEB)

    Abhilash, P.M. [Department of Mechanical Engineering, IIT Madras, Chennai 600036 (India); Kannan, K., E-mail: krishnakannan@iitm.ac.i [Department of Mechanical Engineering, IIT Madras, Chennai 600036 (India); Varkey, Bijo [Advanced Design Department, MRF Ltd., Chennai 600019 (India)

    2010-04-15

    The objective of the present work is to predict the degree of curing for a rectangular slab of rubber, which was subjected to non-uniform thermal history. As the thermal conductivity of rubber is very low, the temperature gradient across a slab is quite large, which leads to non-uniform vulcanization, and hence non-uniform mechanical properties-an inhomogeneous material. Since curing is an exothermic reaction, heat transfer and chemical reactions are solved in a coupled manner. The effect of heat generation on curing is also discussed.

  3. Experimental observation of internal water curing of concrete

    DEFF Research Database (Denmark)

    Lura, Pietro; Jensen, Ole Mejlhede

    2007-01-01

    Internal water curing has a significant effect on concrete. In addition to affecting hydration and moisture distribution, it influences most concrete properties, such as strength, shrinkage, cracking, and durability. The following paper is an overview of experimental methods to study internal water...... curing of concrete and its consequences. The special techniques needed to study internal water curing are dealt with along with the consequences of this process. Examples of applications are given and new measuring techniques that may potentially be applied to this field are addressed....

  4. Study on curing reaction of 4-aminophenoxyphthalonitrile/bisphthalonitrile

    Institute of Scientific and Technical Information of China (English)

    Xiao

    2010-01-01

    A series of phthalonitrile blending resins were prepared from 4-aminophenoxyphthalonitrile (APN) and 4,4'-bis (3,4-dicyanophenoxy)biphenyl (BPH) by directly powder-mixing and copolymerization. Differential scanning calorimeter (DSC) and dynamic rheology were used to study the curing reaction behaviors of APN/BPH blends, and the results indicated that the introduction of APN accelerated the curing rate of BPH, and the existence of BPH decreased the curing temperature of APN/BPH systems. The thermal stability of postcured APN/BPH resins was investigated by thermogravimetric analysis (TGA), and the TGA results indicated that the crosslinked polymers of APN/BPH systems possessed good thermal stability.

  5. Studies on the structural changes during curing of epoxy and its blend with CTBN

    Science.gov (United States)

    Srivastava, Kavita; Rathore, Ashwani Kumar; Srivastava, Deepak

    2018-01-01

    Cashew nut shell liquid (CNSL), an agricultural renewable resource material, produces natural phenolic distillates such as cardanol. Cardanol condenses with formaldehyde at the ortho- and para-position of the phenolic ring under acidic or alkaline condition to yield a series of polymers of novolac- or resol-type phenolic resins. These phenolic resins may further be modified by epoxidation with epichlorohydrin to duplicate the performance of such phenolic-type novolacs (CFN). The structural changes during curing of blend samples of epoxy and carboxyl terminated poly (butadiene-co-acrylonitrile) (CTBN) were studies by Fourier-transform infrared (FTIR) spectrophotometer. The epoxy samples were synthesized by biomass material, cardanol. Blend sample was prepared by physical mixing of CTBN ranging between 0 and 20 weight percent CTBN liquid rubber into cardanol-based epoxidized novolac (CEN) resin. The FTIR spectrum of uncured blend sample clearly indicated that there appeared a band in the region of 3200-3500 cm- 1 which might be due to the presence of phenolic hydroxyl group and sbnd OH group of the opened epoxide. Pure epoxy resin showed peaks near 856 cm- 1 which might be due to oxirane functionality of the epoxidized novolac resin. Both epoxy and its blend sample was cured with polyamine. The cure temperature of CEN resin was found to be decreased by the incorporation of CTBN. The decomposition behavior was also studied by thermogravimetric analyzer (TGA). Two-step decomposition behavior was observed in both epoxy and its blend samples.

  6. New insight-guided approaches to detect, cure, prevent and eliminate malaria.

    Science.gov (United States)

    Kumar, Sushil; Kumari, Renu; Pandey, Richa

    2015-05-01

    scaffold structure several of the desired properties of malaria cure and control are exemplified by OZ439, NITD609, ELQ300 and tafenoquine that are already undergoing clinical trials, and decoquinate, usnic acid, torin-2, ferroquine, WEHI-916, MMV396749 and benzothiophene-type N-myristoyltransferase (NMT) inhibitors, which are candidates for future clinical usage. Among these, NITD609, ELQ300, decoquinate, usnic acid, torin-2 and NMT inhibitors not only cure simple malaria and are prophylactic against simple malaria, but they also cure relapsing malaria.

  7. Physical properties of self-curing concrete (SCUC

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-08-01

    The results show that the use of self-curing agent (Ch. in concrete effectively improves the physical properties compared with conventional concrete. On the other hand, up to 15% saturated leca was effective while 20% saturated leca was effective for permeability and mass loss but adversely affects the sorptivity and volumetric water absorption. Self-curing agent Ch. was more effective than self-curing agent leca. In all cases, both 2% Ch. and 15% leca were the optimum values. Higher cement content and/or lower water–cement ratio leads to more effective results of self-curing agents in concrete. Incorporation of silica fume into concrete mixtures enhances all physical properties.

  8. Steam-cured stabilised soil blocks for masonry construction

    Energy Technology Data Exchange (ETDEWEB)

    Venkatarama Reddy, B.V. [Indian Inst. of Science, Bangalore (India). Dept. of Civil Engineering; Lokras, S.S. [Indian Inst. of Science, Bangalore (India). ASTRA

    1998-12-01

    Energy-efficient, economical and durable building materials are essential for sustainable construction practices. The paper deals with production and properties of energy-efficient steam-cured stabilised soil blocks used for masonry construction. Problems of mixing expansive soil and lime, and production of blocks using soil-lime mixtures have been discussed briefly. Details of steam curing of stabilised soil blocks and properties of such blocks are given. A comparison of energy content of steam-cured soil blocks and burnt bricks is presented. It has been shown that energy-efficient steam cured soil blocks (consuming 35% less thermal energy compared to burnt clay bricks) having high compressive strength can be easily produced in a decentralised manner. (orig.)

  9. Products Claiming to "Cure" Cancer Are a Cruel Deception

    Science.gov (United States)

    ... products claiming to cure cancer on websites or social media platforms, such as Facebook and Instagram. According to Nicole Kornspan, M.P.H., a consumer safety officer at the U.S. Food and Drug ...

  10. Rubber composites cured with sulphur and peroxide and ...

    Indian Academy of Sciences (India)

    Besides classical applications of rubber products in tyres, ... application of sulphur curing systems leads to the forming ..... mobile sulphidic cross-links which promote crystallization of NR. ... PhD Thesis (Kingston, Ontario: Queen's University).

  11. GENERAL ENVIRONMENTAL CORPORATION; CURE ELECTROCOAGULATION TECHNOLOGY: INNOVATIVE TECHNOLOGY EVALUATION REPORT

    Science.gov (United States)

    The CURE electrocoagulation technology was demonstrated under the Superfund Innovative Technology Evaluation (SITE) program at the U.S. Department of Energy (DOE) Rocky Flats Environmental Technology Site (RFETS), where water from the solar evaporation ponds (SEPs) was contaminat...

  12. Influence of curing regimes on compressive strength of ultra high ...

    Indian Academy of Sciences (India)

    142 MPa with change in curing regimes. The samples ..... Guide, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, ... the 5th International Conference on the Chemistry of Cement, Tokyo, Japan, pp.

  13. Factors affecting dry-cured ham consumer acceptability.

    Science.gov (United States)

    Morales, R; Guerrero, L; Aguiar, A P S; Guàrdia, M D; Gou, P

    2013-11-01

    The objectives of the present study were (1) to compare the relative importance of price, processing time, texture and intramuscular fat in purchase intention of dry-cured ham through conjoint analysis, (2) to evaluate the effect of dry-cured ham appearance on consumer expectations, and (3) to describe the consumer sensory preferences of dry-cured ham using external preference mapping. Texture and processing time influenced the consumer preferences in conjoint analysis. Red colour intensity, colour uniformity, external fat and white film presence/absence influenced consumer expectations. The consumer disliked hams with bitter and metallic flavour and with excessive saltiness and piquantness. Differences between expected and experienced acceptability were found, which indicates that the visual preference of consumers does not allow them to select a dry-cured ham that satisfies their sensory preferences of flavour and texture. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Room-Temperature-Cured Copolymers for Lithium Battery Gel Electrolytes

    Science.gov (United States)

    Meador, Mary Ann B.; Tigelaar, Dean M.

    2009-01-01

    Polyimide-PEO copolymers (PEO signifies polyethylene oxide) that have branched rod-coil molecular structures and that can be cured into film form at room temperature have been invented for use as gel electrolytes for lithium-ion electric-power cells. These copolymers offer an alternative to previously patented branched rod-coil polyimides that have been considered for use as polymer electrolytes and that must be cured at a temperature of 200 C. In order to obtain sufficient conductivity for lithium ions in practical applications at and below room temperature, it is necessary to imbibe such a polymer with a suitable carbonate solvent or ionic liquid, but the high-temperature cure makes it impossible to incorporate and retain such a liquid within the polymer molecular framework. By eliminating the high-temperature cure, the present invention makes it possible to incorporate the required liquid.

  15. Method for curing polymers using variable-frequency microwave heating

    Science.gov (United States)

    Lauf, Robert J.; Bible, Don W.; Paulauskas, Felix L.

    1998-01-01

    A method for curing polymers (11) incorporating a variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34). By varying the frequency of the microwave signal, non-uniformities within the cavity (34) are minimized, thereby achieving a more uniform cure throughout the workpiece (36). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. The furnace cavity (34) may be adapted to be used to cure materials defining a continuous sheet or which require compressive forces during curing.

  16. Evaluation of methods for measuring relative permeability of anhydride from the Salado Formation: Sensitivity analysis and data reduction

    International Nuclear Information System (INIS)

    Christiansen, R.L.; Kalbus, J.S.

    1997-05-01

    This report documents, demonstrates, evaluates, and provides theoretical justification for methods used to convert experimental data into relative permeability relationships. The report facilities accurate determination of relative permeabilities of anhydride rock samples from the Salado Formation at the Waste Isolation Pilot Plant (WIPP). Relative permeability characteristic curves are necessary for WIPP Performance Assessment (PA) predictions of the potential for flow of waste-generated gas from the repository and brine flow into repository. This report follows Christiansen and Howarth (1995), a comprehensive literature review of methods for measuring relative permeability. It focuses on unsteady-state experiments and describes five methods for obtaining relative permeability relationships from unsteady-state experiments. Unsteady-state experimental methods were recommended for relative permeability measurements of low-permeability anhydrite rock samples form the Salado Formation because these tests produce accurate relative permeability information and take significantly less time to complete than steady-state tests. Five methods for obtaining relative permeability relationships from unsteady-state experiments are described: the Welge method, the Johnson-Bossler-Naumann method, the Jones-Roszelle method, the Ramakrishnan-Cappiello method, and the Hagoort method. A summary, an example of the calculations, and a theoretical justification are provided for each of the five methods. Displacements in porous media are numerically simulated for the calculation examples. The simulated product data were processed using the methods, and the relative permeabilities obtained were compared with those input to the numerical model. A variety of operating conditions were simulated to show sensitivity of production behavior to rock-fluid properties

  17. Syntheses and properties of complex resins obtained by the reaction of polyethyleneimine with maleic anhydride-isobutene copolymer

    International Nuclear Information System (INIS)

    Usami, Shiro; Hasegawa, Kiyoshi; Takata, Kyoko; Naito, Ryunosuke; Uchida, Hiroshi; Kozuka, Hiroshi.

    1985-01-01

    Complex resins obtained by the reaction of polyethyleneimine with maleic anhydride-isobutene copolymer around 100 0 C revealed selective ion adsorption depending on the equivalent ratio of nitrogen to carboxyl group (N/COOH). In detail, polyanion-excess complex resins (N/COOH 2+ , Pb 2+ , Zn 2+ and Ni 2+ , and resins containing excess polycation (N/COOH > 1) for metal complex anions such as [CrO 4 ] 2- , [Ag(S 2 O 3 ) 2 ] 3- and [Fe(CN) 6 ] 4- . Furthermore, the polycation-excess complex resins had high adsorption capacity for uranium in solution, for example, a polycationic resin (N/COOH = 1.79) had an adsorption capacity of more than 100 mg U/g-dry base resin in a 75 ppm uranium solution. It also adsorbed and recovered uranium from solution contatining such infinitesimal amounts of uranium as sea water. The results from electron probe X-ray microanalyser (EPMA) of a polycationic resin (N/COOH = 1.79) indicated that cations such as Ca 2+ and Mg 2+ , abundant in sea water, were not adsorbed at all while such anions as Cl - and S 2- were adsorbed. It was found that Br - , I - , etc. were not adsorbed from sea water while these anions were adsorbed from the solutions containing them independently. The result indicated that Cl - in sea water probably interfered the adsorption of Br - , I - , etc. However, uranium was adsorbed from sea water in spite of its extremely low concentration without any disturbance of other co-existing ions. It was found that Ni 2+ and Cu 2+ were also adsorbed. (author)

  18. Preparation and characterization of new succinic anhydride grafted Posidonia for the removal of organic and inorganic pollutants

    International Nuclear Information System (INIS)

    Chadlia, Aguir; Mohamed, Khalfaoui; Najah, Laribi; Farouk, M'henni Mohamed

    2009-01-01

    The present work describes the preparation of new chelating materials derived from Posidonia for adsorption of heavy metal ions and dye in aqueous solution. The first part of this report deals with the chemical modification of Posidonia with succinic anhydride. Thus, we have obtained materials with various succinyl groups contents (from 29.8 to 39.2%). The obtained materials were characterized by infrared and CP/MAS 13 C-RMN spectroscopy. The rate of succinyl content of the modified Posidonia was determined by saponification. The second part is devoted to the evaluation of the adsorption capacity of metal ions such as Pb 2+ and dye such as direct red 75 (DR75) for raw and modified Posidonia materials. Two possible ways for the adsorption of these pollutants are studied: adsorption of each pollutant alone onto these supports, and cumulative adsorption of both metal ions and dye on the same supports. In the last case, the pollutant is adsorbed successively from two different solutions. The effects of pollutants concentration, support dose, pH, contact time and temperature on adsorption of each pollutant were evaluated. The results showed that the raw and modified Posidonia show a high capacity for Pb 2+ adsorption. The capacity of modified Posidonia saturated with Pb 2+ to adsorb DR75 was found 147.12 mg g -1 . While the adsorption capacity of the nonsaturated modified Posidonia was equal to 81.63 mg g -1 . The pseudo-second-order model was the best to represent adsorption kinetics of DR75. The pseudo-first-order model would be better for fitting the adsorption kinetic process of Pb 2+ onto raw and modified Posidonia. The adsorption isotherms of Pb 2+ could be described by the Jossens equation model. Any of the tested models can describe the adsorption of DR75 onto the studied materials. These results confirm that the adsorption of DR75 from aqueous solution was multilayer.

  19. Alveolar macrophages have a dual role in a rat model for trimellitic anhydride-induced occupational asthma

    International Nuclear Information System (INIS)

    Valstar, Dingena L.; Schijf, Marcel A.; Nijkamp, Frans P.; Storm, Gert; Arts, Josje H.E.; Kuper, C. Frieke; Bloksma, Nanne; Henricks, Paul A.J.

    2006-01-01

    Occupational exposure to low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter inhaled compounds. These cells can produce many different mediators that have a putative role in asthma. In this study, we examined the role of AMs in lung function and airway inflammation of rats exposed to TMA. Female Brown Norway rats were sensitized by dermal application of TMA or received vehicle alone on days 0 and 7. One day before challenge, rats received intratracheally either empty or clodronate-containing liposomes to deplete the lungs of AMs. On day 21, all rats were challenged by inhalation of TMA in air. Lung function parameters were measured before, during, within 1 h after, and 24 h after challenge. IgE levels and parameters of inflammation and tissue damage were assessed 24 h after challenge. Sensitization with TMA led to decreased lung function parameters during and within 1 h after challenge as compared to non-sensitized rats. AM depletion alleviated the TMA-induced drop in lung function parameters and induced a faster recovery compared to sham-depleted TMA-sensitized rats. It also decreased the levels of serum IgE 24 h after challenge, but did not affect the sensitization-dependent increase in lung lavage fluid IL-6 and tissue TNF-α levels. In contrast, AM depletion augmented the TMA-induced tissue damage and inflammation 24 h after challenge. AMs seem to have a dual role in this model for TMA-induced occupational asthma since they potentiate the immediate TMA-induced decrease in lung function but tended to dampen the TMA-induced inflammatory reaction 24 h later

  20. Chemical modification with phthalic anhydride and chitosan: Viable options for the stabilization of raw starch digesting amylase from Aspergillus carbonarius.

    Science.gov (United States)

    Nwagu, Tochukwu Nwamaka; Okolo, Bartholomew; Aoyagi, Hideki; Yoshida, Shigeki

    2017-06-01

    The raw starch digesting type of amylase (RSDA) presents greater opportunities for process efficiency at cheaper cost and shorter time compared to regular amylases. Chemical modification is a simple and rapid method toward their stabilization for a wider application. RSDA from Aspergillus carbonarius was modified with either phthalic anhydride (PA) or chitosan. Activity retention was 87.3% for PA-modified and 80.9% for chitosan-modified RSDA. Optimum pH shifted from 5 to 7 after PA-modification. Optimum temperature changed from 30°C (native) to 30-40°C and 60°C for PA-modified and chitosan-modified, respectively. Activation energy (kJmol -1 ) for hydrolysis was 13.5, 12.7, and 10.2 while the activation energy for thermal denaturation was 32.8, 80.3, 81.9 for free, PA-modified and chitosan-modified, respectively. The specificity constants (V max /K m ) were 73.2 for PA-modified, 63.1 for chitosan-modified and 77.1 for native RSDA. The half-life (h) of the RSDA at 80°C was increased from 6.1 to 25.7 for the PA-modified and 138.6 for the chitosan derivative. Modification also led to increase in D value, activation enthalpy and Gibbs free energy of enzyme deactivation. Fluorescence spectra showed that center of spectral mass decreased for the PA-modified RSDA but increased for chitosan modified RSDA. Copyright © 2017 Elsevier B.V. All rights reserved.