WorldWideScience

Sample records for peroxide cured polypropylene-ethylene

  1. Studies on the influence of structurally different peroxides in polypropylene/ethylene alpha olefin thermoplastic vulcanizates (TPVs

    Directory of Open Access Journals (Sweden)

    2008-03-01

    Full Text Available Novel thermoplastic vulcanizates (TPVs based on polypropylene (PP and new generation ethylene-octene copolymer (EOC have been developed by dynamic vulcanization process, which involves melt-mixing and simultaneously crosslinking a rubber with a thermoplastic. In this paper technologically compatibilized blends of PP and EOC were dynamically vulcanized by coagent assisted peroxide crosslinking system. The effect of structurally different types of peroxides, namely dicumyl peroxide, di-tert butyl peroxy isopropyl benzene and tert-butyl cumyl peroxide with varying concentrations on the properties on TPVs was mainly studied. The physico-mechanical, thermal and morphological properties of these TPVs were characterized by using X-ray diffraction (XRD, differential scanning calorimeter (DSC and scanning electron microscopy (SEM.

  2. Irradiation of isotactic polypropylene and polypropylene/ethylene-propylene (diene-monomer) blends

    NARCIS (Netherlands)

    Gisbergen, van J.G.M.; Meijerink, J.I.; Overbergh, N.; Kleintjes, L.; Lemstra, P.J.

    1989-01-01

    The influence of electron beam irradiation on rheological properties and morphology of polypropylene and polypropylene/ethylene-propylene rubber blends was studied. Electron beam irradiation of isotactic PP causes pronounced chain scission (degradation) at dosis = 100 kGy. Melt viscosity can be

  3. Thermal stabilities of various rubber vulcanization cured by sulfur, peroxide and gamma radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.; Shamshad Ahmed; Abdel Aziz, M.M.

    1999-01-01

    Sulfur and peroxide-cured rubber vulcanizates of NR and EPDM were obtained by blending the elastomers with fillers, antioxidants and appropriate accelerators, followed by vulcanization at 150 - 160 degree C. Blends of the same elastomers with appropriate co-agents and additives were also cured by gamma radiation at 150 and 200 kGy. A comparison of the thermal stabilities of these vulcanizates prepared by different curing techniques has been made by thermogravimetric analysis (TGA), assessed on the basis of comparison of DTG peak maxima, temperature for loss of 50% mass and actual thermal curves. The comparison reveals that the sulfur-cured vulcanizates are less thermally stable than their peroxide-cured counterparts. This may be attributed to the presence of a stronger C-C bond in case of peroxide-cured vulcanizates compared to weaker C-S sub x-C bond in case of sulfur-cured vulcanizates. However, compared to peroxide-cured vulcanizates, radiation-cured formulations demonstrated much improved thermal stability. This may originate from the existence of more uniformly distributed crosslinks and the enhanced rate of crosslink formation in the radiation process as compared to peroxide curing. In all the formulations whether sulfur, peroxide or radiation-cured, the natural rubber vulcanizates were found to be thermally much inferior to the synthetic contender, EPDM. Influence of variation of the amount of co-agent and other additives on the thermal stabilities of formulations of radiation cured NR and EPDM vulcanizates was also investigated

  4. 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).

  5. 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®

  6. Effect of material and processing parameters on mechanical properties of Polypropylene/Ethylene-Propylene-Diene-Monomer/clay nanocomposites

    International Nuclear Information System (INIS)

    Hejazi, Iman; Sharif, Farhad; Garmabi, Hamid

    2011-01-01

    Highlights: → Improved mechanical properties over a broad range of processing conditions. → Moderate levels of clay and processing parameters lead to higher toughness of TPO. → Significant improvement of tensile strength and modulus of TPO materials. -- Abstract: Polypropylene/Ethylene-Propylene-Diene-Monomer (PP/EPDM) blends are well known for having a combination of favourable mechanical properties. In this paper, addition of organoclay to PP/EPDM to make PP/EPDM nanocomposites with enhanced mechanical properties is studied. PP/EPDM/organoclay nanocomposites were prepared using a lab scale twin-screw extruder. Maleic anhydride grafted polypropylene (PP-g-MA) was used to enhance the intercalation/exfoliation process and to create good adhesion at the polymer/polymer and polymer/filler interfaces. Taguchi method was employed to deign the experiments and optimize material and processing parameters for optimized mechanical properties. Organoclay (NC) and compatibilizer content were selected as material parameters and the main processing variables were feeding rate and average shear rate (RPM). X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to study the microstructure of the nanocomposites samples. It was observed that NC content and shear rate in extruder improved the tensile strength and modulus. Another important result was the insignificant effect of NC content on impact strength while increasing shear rate first increased and then decreased the impact strength.

  7. Roughness comparison of heat cured type of acrylic resin in disinfectant solution immersion (Immersion in a solution of alkaline peroxide and 75% Celery extract (Apium graveolens L

    Directory of Open Access Journals (Sweden)

    Dewi Puspitasari

    2016-08-01

    Full Text Available Acrylic resin denture base has the properties absorbing that affecting physical and mechanical properties. One of the physical properties of acrylic resin is surface roughness. The aim of the study was to find out the roughness effect on heat cured acrylic that was immersed in alkaline peroxide and 75% celery (Apium graveoens L extract as a disinfectant solution. The study was a true experimental and posttest with control group designed with a rectangular shape size 65 x 10 x 3.3 mm based on the ISO standard 1567, six samples were used for alkaline peroxide, celery extract 75% and aquadest group for 5 and 15 days. A Surface Roughness Tester was used for the surface roughness changes observation. The statistical test used One-way ANOVA and post hoc Bonferroni. The results of this study showed the value of roughness on 5 days for alkaline peroxide (1.51 µm is greater than celery extract (0.36µm and aquadest (0.30 µm. The soaking for 15 days in alkaline peroxide (1.52 µm is greater than 75% celery extracts (0.38 µm and aquadest (0.34 µm. Alkaline peroxide caused higher roughness value of heat cured acrylic resin than 75% celery extract.

  8. 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.

  9. 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)

  10. 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

  11. Hydrogen peroxide safety issues

    International Nuclear Information System (INIS)

    Conner, W.V.

    1993-01-01

    A literature survey was conducted to review the safety issues involved in handling hydrogen peroxide solutions. Most of the information found in the literature is not directly applicable to conditions at the Rocky Flats Plant, but one report describes experimental work conducted previously at Rocky Flats to determine decomposition reaction-rate constants for hydrogen peroxide solutions. Data from this report were used to calculate decomposition half-life times for hydrogen peroxide in solutions containing several decomposition catalysts. The information developed from this survey indicates that hydrogen peroxide will undergo both homogeneous and heterogeneous decomposition. The rate of decomposition is affected by temperature and the presence of catalytic agents. Decomposition of hydrogen peroxide is catalyzed by alkalies, strong acids, platinum group and transition metals, and dissolved salts of transition metals. Depending upon conditions, the consequence of a hydrogen peroxide decomposition can range from slow evolution of oxygen gas to a vapor, phase detonation of hydrogen peroxide vapors

  12. Production of uranium peroxide

    International Nuclear Information System (INIS)

    Caropreso, F.E.; Kreuz, D.F.

    1977-01-01

    A process is claimed of recovering uranium values as uranium peroxide from an aqueous uranyl solution containing dissolved vanadium and sodium impurities by treating the uranyl solution with hydrogen peroxide in an amount sufficient to have an excess of at least 0.5 parts H 2 O 2 per part of vanadium (V 2 O 5 ) above the stoichiometric amount required to form the uranium peroxide, the hydrogen peroxide treatment is carried out in three sequential phases consisting of I, a precipitation phase in which the hydrogen peroxide is added to the uranyl solution to precipitate the uranium peroxide and the pH of the reaction medium maintained in the range of 2.5 to 5.5 for a period of from about 1 to 60 minutes after the hydrogen peroxide addition; II, a digestion phase in which the pH of the reaction medium is maintained in the range of 3.0 to 7.0 for a period of about 5 to 180 minutes and III, a final phase in which the pH of the reaction medium is maintained in the range of 4.0 to 7.0 for a period of about 1 to 60 minutes during which time the uranium peroxide is separated from the reaction solution containing the dissolved vanadium and sodium impurities. The excess hydrogen peroxide is maintained during the entire treatment up until the uranium peroxide is separated from the reaction medium

  13. 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

  14. Electron-beam curing of paints and varnishes on wood panels

    International Nuclear Information System (INIS)

    Grosmaire, P.R.

    1977-01-01

    An analysis is presented of the relative costs of curing polyester coated wood panels using (a) the conventional peroxide cure, (b) treatment with UV light, or (c) electron beams. Electron treatment is shown to compare very favourably with either of the other treatments. (U.K.)

  15. 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

  16. 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...

  17. Comparative studies on sulfur, peroxide, and radiation vulcanization of EFDM rubber

    International Nuclear Information System (INIS)

    Abdel-Aziz, M.M.; Basfar, A.A.; Mofti, S.

    2000-01-01

    The temperature and concentration dependence of the vulcanization characteristics and mechanical properties of epdm rubber containing various concentrations of peroxide compounds was studied. The peroxides used are Luperox Di, Luperox 500-40 Ke, peroximon Dc Sc and peroximon Dc 40 Ke. The optimum cure parameters for the different types of peroxides indicated that Luperox Di, relatively, Give the best properties among the studied peroxides. The mechanical properties of EPDM containing different concentrations of Luperox Di and vulcanized at different temperatures were compared with those of either radiation or sulfur-cured EPDM. The modulus stress and tensile strength of the Luperox Di-cured EPDM were found to increase with either increasing the temperature of vulcanization and/ or concentration of the peroxide. Moreover, the tensile strength values are much higher than those of the sulfur-cured samples, except for those with low concentration of peroxide and vulcanized at relatively low temperature. A comparable result to those of the chemically vulcanized samples was attained by the radiation- vulcanized samples containing 1 phr of crosslinking agent and irradiated to 150 KGy

  18. 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

  19. 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.)

  20. Protein oxidation and peroxidation

    DEFF Research Database (Denmark)

    Davies, Michael Jonathan

    2016-01-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard...... to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners...... and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals...

  1. 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.)

  2. 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

  3. Polymerization, structure and track recording properties of CR-39 cured with UV photoinitiators

    International Nuclear Information System (INIS)

    Stejny, J.; Carrell, J.; Palmer, M.J.

    2000-01-01

    CR-39 monomer was cured isothermally at temperatures from 54.5 to 115 deg. C with UV sensitive photoinitiators to high conversions. The use of photoinitiators allowed the cure of CR-39 isothermally at high temperatures and eliminated the danger of thermal runaway present in the conventionally used thermal initiation with peroxides. It was found that the properties of the UV photoinitiated CR-39 were similar to the conventionally polymerized resin

  4. 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

  5. Peroxide organometallic compounds and their transformations

    International Nuclear Information System (INIS)

    Razuvaev, G.A.; Brilkina, T.G.

    1976-01-01

    A survey is given experimental works on synthesis and reactions of peroxide organometallic compounds. Reactions have been considered of organometallic compounds with oxygen and organic peroxides which result in formation of both peroxide and non-peroxide products. Possible routes and mechanisms of chemical transformations of peroxide organometallic compounds have been discussed. Reactions of organometallic compounds with oxygen and peroxides have been considered

  6. 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

  7. 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.)

  8. 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...

  9. Influence of curing agents on gelation and exotherm behaviour of an ...

    Indian Academy of Sciences (India)

    Unsaturated polyester resin; resin curing; gel time; exotherm behaviour; peroxide initiator. 1. Introduction ... process cycle to manufacture a composite part. The magni- ... work, which makes sudden irreversible transformation from a liquid resin to a ... anistic models attempt to quantify the balance of chemical species taking ...

  10. 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.

  11. 21 CFR 172.802 - Acetone peroxides.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acetone peroxides. 172.802 Section 172.802 Food and... Multipurpose Additives § 172.802 Acetone peroxides. The food additive acetone peroxides may be safely used in... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide...

  12. 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)

  13. 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

  14. Improved ozone resistance of styrene-butadiene rubber cured by a combination of sulfur and ionizing radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.; Silverman, Joseph

    1995-01-01

    Fourier Transform Infrared (FTIR) studies performed in this work indicate that high ozone resistance of Styrene-Butadiene Rubber (SBR) formulations cured by a combination of sulfur and ionizing radiation is associated with unusually high vinyl concentration. On the other hand, sulfur cured SBR formulations with low vinyl concentration have poor ozone resistance. Curing with peroxides which involves chemistry similar to that of radiation curing, also leads to high vinyl concentration (relative to sulfur curing) and high ozone resistance. Increasing the absorbed dose in sulfur-radiation cured samples decreased the high vinyl content to a point where the ozone resistance declined greatly. Carbon black was shown to reduce the absorption of both the transvinylene and the vinyl unsaturation groups, but not to the same extent in all formulations. Also, the carbon black seems to play a greater role in the absorption of the unsaturation as sulfur increases. (Author)

  15. Improved ozone resistance of styrene-butadiene rubber cured by a combination of sulfur and ionizing radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.; Silverman, J.

    1995-01-01

    Fourier Transform (FTIR) studies performed in this work indicate that high ozone resistance of Styrene-Butadiene Rubber (SBR) formulations cured by a combination of sulfur and ionizing radiation is associated with unusually high vinyl concentration. On the other hand, sulfur cured SBR formulations with low vinyl concentration have poor ozone resistance. Curing with peroxides which involves chemistry similar to that of radiation curing, also leads to high vinyl concentration (relative to sulfur curing) and high ozone resistance. Increasing the absorbed dose in sulfur-radiation cured samples decreased the high vinyl content to a point where the ozone resistance declined greatly. Carbon black was shown to reduce the absorption of both the transvinylene and the vinyl unsaturation groups, but not to the same extent in all formulations. Also, the carbon black seems to play a greater role in the absorption of the unsaturation as sulfur increases. (Author)

  16. 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)

  17. 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.

  18. Dsc cure kinetics of an unsaturated polyester resin using empirical kinetic model

    International Nuclear Information System (INIS)

    Abdullah, I.

    2015-01-01

    In this paper, the kinetics of curing of unsaturated polyester resin initiated with benzoyl peroxide was studied. In case of unsaturated polyester (UP) resin, isothermal test alone could not predict correctly the curing time of UP resin. Therefore, isothermal kinetic analysis through isoconventional adjustment was used to correctly predict the curing time and temperature of UP resin. Isothermal kinetic analysis through isoconversional adjustment indicated that 97% of UP resin cures in 33 min at 120 degree C. Curing of UP resin through microwaves was also studied and found that 67% of UP resin cures in 1 min at 120 degree C. The crosslinking reaction of UP resin is so fast at 120 degree C that it becomes impossible to predict correctly the curing time of UP resin using isothermal test and the burial of C=C bonds in microgels makes it impossible to be fully cured by microwaves at 120 degree C. The rheological behaviour of unsaturated polyester resin was also studied to observe the change in viscosity with respect to time and temperature. (author)

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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)

  5. 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.

  6. 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.

  7. 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...

  8. 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)

  9. 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

  10. 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.

  11. 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).

  12. Influence of different curing systems on the physico-mechanical properties and stability of SBR and NR rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Basfar, A.A. E-mail: abasfar@kacst.edu.sa; Abdel-Aziz, M.M.; Mofti, S

    2002-01-01

    The physical properties of radiation, sulfur and peroxide-cured styrene-butadiene rubber (SBR) and natural rubber (NR) were compared. The dependence of the mechanical properties of the radiation-vulcanized SBR and NR on the coagent concentration and radiation dose was studied. The effect of thermal aging on the mechanical properties of the different rubber formulations was discussed. The radiation-cured formulations of SBR have superior mechanical properties and thermal stability compared with those of the chemically vulcanized compounds. Whereas, the radiation-cured formulations of NR have similar mechanical properties but superior thermal stability (based on the % change in E after thermal aging), when compared with those of the sulfur-vulcanized compounds and slightly better than those of the peroxide-vulcanized compounds.

  13. 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...

  14. Uranium precipitation with hydrogen peroxide

    International Nuclear Information System (INIS)

    Brown, R.A.

    1980-01-01

    Although hydrogen peroxide precipitation of uranium continues to be used primarily as means of producing a high purity yellowcake, it has also become an important process due to its superior physical properties. Processing costs such as filtering, drying and/or calcining and drumming, can be reduced. 5 refs

  15. Hydrogen peroxide: importance and determination

    OpenAIRE

    Mattos, Ivanildo Luiz de; Shiraishi, Karina Antonelli; Braz, Alexandre Delphini; Fernandes, João Roberto

    2003-01-01

    A brief discussion about the hydrogen peroxide importance and its determination is presented. It was emphasized some consideration of the H2O2 as reagent (separated or combined), uses and methods of analysis (techniques, detection limits, linear response intervals, sensor specifications). Moreover, it was presented several applications, such as in environmental, pharmaceutical, medicine and food samples.

  16. 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.)

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 21 CFR 529.1150 - Hydrogen peroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... DRUGS, FEEDS, AND RELATED PRODUCTS CERTAIN OTHER DOSAGE FORM NEW ANIMAL DRUGS § 529.1150 Hydrogen peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide...

  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. Thermochemistry of cyclic acetone peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Sinditskii, V.P., E-mail: vps@rctu.ru [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Kolesov, V.I.; Egorshev, V.Yu.; Patrikeev, D.I. [Mendeleev University of Chemical Technology, 9 Miusskaya Square, 125047 Moscow (Russian Federation); Dorofeeva, O.V. [Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

    2014-06-01

    Highlights: • Old data on DADP and TATP enthalpies of formation have been revised. • Combining Gaussian-4 (G4) theory with an isodesmic reaction scheme allowed calculated enthalpies of formation of TATP and DADP. • Oxygen bomb calorimetry measurements allowed experimental enthalpies of formation of the peroxides. • Both experimental and calculated values show a satisfactory agreement between each other. • The newly obtained enthalpies reasonably account for the observed derivative parameters: heats of decomposition, combustion, and explosion. - Abstract: Two potentially initiating explosive peroxides, diacetonediperoxide (DADP) and triacetonetriperoxide (TATP), were studied in respect to their thermochemical properties. To get the internally self-consistent estimations of gas-phase enthalpy of formation of DADP and TATP, their values were calculated by combining Gaussian-4 (G4) theory with an isodesmic reaction scheme. The energies of combustion (Δ{sub c}U) were measured and the standard enthalpies of formation (Δ{sub f}H{sub 298}{sup °}) of DADP and TATP were derived using the standard enthalpies of formation of the combustion products. The heat of explosion was measured for small low-pressed charges of the peroxides. The obtained enthalpies of formation of DADP and TATP were found to agree well with quantum chemical calculations and reasonably account for the observed derivative parameters: heats of decomposition, combustion, and detonation.

  6. Hydrogen peroxide kinetics in water radiolysis

    Science.gov (United States)

    Iwamatsu, Kazuhiro; Sundin, Sara; LaVerne, Jay A.

    2018-04-01

    The kinetics of the formation and reaction of hydrogen peroxide in the long time γ- radiolysis of water is examined using a combination of experiment with model calculations. Escape yields of hydrogen peroxide on the microsecond time scale are easily measured with added radical scavengers even with substantial amounts of initial added hydrogen peroxide. The γ-radiolysis of aqueous hydrogen peroxide solutions without added radical scavengers reach a steady state limiting concentration of hydrogen peroxide with increasing dose, and that limit is directly proportional to the initial concentration of added hydrogen peroxide. The dose necessary to reach that limiting hydrogen peroxide concentration is also proportional to the initial concentration, but dose rate has a very small effect. The addition of molecular hydrogen to aqueous solutions of hydrogen peroxide leads to a decrease in the high dose limiting hydrogen peroxide concentration that is linear with the initial hydrogen concentration, but the amount of decrease is not stoichiometric. Proton irradiations of solutions with added hydrogen peroxide and hydrogen are more difficult to predict because of the decreased yields of radicals; however, with a substantial increase in dose rate there is a sufficient decrease in radical yields that hydrogen addition has little effect on hydrogen peroxide decay.

  7. 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...

  8. 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

  9. 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.

  10. 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.)

  11. 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.

  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. Red Wine and Pomegranate Extracts Suppress Cured Meat Promotion of Colonic Mucin-Depleted Foci in Carcinogen-Induced Rats.

    Science.gov (United States)

    Bastide, Nadia M; Naud, Nathalie; Nassy, Gilles; Vendeuvre, Jean-Luc; Taché, Sylviane; Guéraud, Françoise; Hobbs, Ditte A; Kuhnle, Gunter G; Corpet, Denis E; Pierre, Fabrice H F

    2017-01-01

    Processed meat intake is carcinogenic to humans. We have shown that intake of a workshop-made cured meat with erythorbate promotes colon carcinogenesis in rats. We speculated that polyphenols could inhibit this effect by limitation of endogenous lipid peroxidation and nitrosation. Polyphenol-rich plant extracts were added to the workshop-made cured meat and given for 14 days to rats and 100 days to azoxymethane-induced rats to evaluate the inhibition of preneoplastic lesions. Colons of 100-d study were scored for precancerous lesions (mucin-depleted foci, MDF), and biochemical end points of peroxidation and nitrosation were measured in urinary and fecal samples. In comparison with cured meat-fed rats, dried red wine, pomegranate extract, α-tocopherol added at one dose to cured meat and withdrawal of erythorbate significantly decreased the number of MDF per colon (but white grape and rosemary extracts did not). This protection was associated with the full suppression of fecal excretion of nitrosyl iron, suggesting that this nitroso compound might be a promoter of carcinogenesis. At optimized concentrations, the incorporation of these plant extracts in cured meat might reduce the risk of colorectal cancer associated with processed meat consumption.

  15. Effect of light energy on peroxide tooth bleaching.

    Science.gov (United States)

    Luk, Karen; Tam, Laura; Hubert, Manfred

    2004-02-01

    Light-activated bleaching is a method of tooth whitening. The authors conducted a study to compare the whitening effects and tooth temperature changes induced by various combinations of peroxide bleaches and light sources. The authors randomly assigned 250 extracted human teeth halves into experimental groups (n = 10). A placebo gel (control), a 35 percent hydrogen peroxide or a 10 percent carbamide peroxide bleach was placed on the tooth surface and was irradiated with no light (control); a halogen curing light; an infrared, or IR, light; an argon laser; or a carbon dioxide, or CO2, laser. Color changes were evaluated immediately, one day and one week after treatment using a value-oriented shade guide and an electronic dental color analyzer. The outer enamel and inner dentin surface temperatures were monitored before and immediately after each 30-second application of light using a thermocouple thermometer. Color and temperature changes were significantly affected by an interaction of the bleach and light variables. The application of lights significantly improved the whitening efficacy of some bleach materials, but it caused significant temperature increases in the outer and inner tooth surfaces. The IR and CO2 laser lights caused the highest tooth temperature increases. Dentists performing an in-office bleaching technique with the use of an additional light source to accelerate tooth whitening should consider the specific bleaching agent being used, as well as the potential risks of heating teeth. A specific combination of bleach and light that demonstrates good color change and little temperature rise should be selected for in-office tooth bleaching.

  16. Detection of hydrogen peroxide with graphyne

    Science.gov (United States)

    Majidi, R.; Karami, A. R.

    2013-12-01

    The effect of hydrogen peroxide on the electronic properties of graphyne has been investigated to explore the possibility of using graphyne based biosensor. We have used density functional theory to study the electronic properties of γ-graphyne in the presence of different number of hydrogen peroxide. The optimal adsorption position, orientation, and distance of hydrogen peroxide adsorbed on the graphyne sheet have been determined by calculating adsorption energy. It is found that γ-graphyne which is an intrinsic semiconductor becomes an n-type semiconductor due to the presence of hydrogen peroxide. The energy band gap of γ-graphyne is decreased by increasing the number of hydrogen peroxide. The results demonstrate that γ-graphyne is a promising candidate for biosensor application because of its electrical sensitivity to hydrogen peroxide.

  17. PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

    Science.gov (United States)

    Seaborg, G.T.; Perlman, I.

    1958-09-16

    reduced state, from hexavalent uranium. It consists in treating an aqueous solution containing such uranium and plutonium ions with sulfate ions in order to form a soluble uranium sulfate complex and then treating the solution with a soluble thorium compound and a soluble peroxide compound in order to ferm a thorium peroxide carrier precipitate which carries down with it the plutonium peroxide present. During this treatment the pH of the solution must be maintained between 2 and 3.

  18. 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

  19. Thermoplastic vulcanizate nanocomposites based on polypropylene/ethylene propylene diene terpolymer (PP/EPDM) prepared by reactive extrusion

    Science.gov (United States)

    Mirzadeh, Amin

    For this work, different grades of polypropylene-g-maleic anhydride polymers were chosen to elucidate the effect of compatibilizer on the nanoclay dispersion level in thermoplastic phase. X-ray diffraction (XRD) patterns along with transmission electron microscopy (TEM) and scanning electron microscope (SEM) micrographs confirmed that prepared PP nanocomposites ranged from intercalated structure to a coexistence of intercalated tactoids and exfoliated layers namely “partially exfoliated” nanocomposite. Among various factors affecting the compatibilizer performance, it is shown that only the relaxation behaviour of compatibilizer correlates directly with the nanocomposites characterization results; higher relaxation times of the compatibilizer are associated with better dispersion of nanoclay. To study the co-continuity development of the nonreactive blends, EPDM and the mentioned PP nanocomposites at various compositions were melt blended using an internal mixer. Based on continuity measurements of TPEs and TPE nanocomposites for both thermoplastic and rubber phase, it is shown that the presence of nanoclay decreases the co-continuity composition range and alters its symmetrical feature. However, this effect is more pronounced in the intercalated nanocomposites than in partially exfoliated nanocomposites. It seems that better nanoclay dispersion limits the reduction of the thermoplastic phase continuity in a manner that the continuity index of the thermoplastic phase for partially exfoliated TPE nanocomposite prepared at high EPDM content (i.e. at 70 wt%) is greater than that of corresponding TPE without nanoclay. According to these results, it is possible to shift to higher EPDM content using partially exfoliated system before formation of matrix-dispersed particle structure which limits thermoplastic vulcanizate production. This should be mentioned that gamma irradiation was carried out in order to fix the EPDM morphology to estimate the continuity of PP using the solvent extraction and gravimetry technique. Additionally, the effect of continuity on rheological behaviour of TPE nanocomposites was investigated. The ultimate goal in this field is to maximize the rubber like behaviour by controlling the blend morphology and the level of crosslinking. Therefore, this study also covers the effects of nanoclay presence and its dispersion level on the crosslinking reaction of thermoplastic vulcanizate nanocomposites prepared by reactive extrusion. Here, the rubber phase was dynamically vulcanized using dimethylol phenolic resin or octylphenol-formaldehyde resin along with stannous chloride dihydrate as the catalyst. In the present study, the dynamic vulcanization of the prepared TPVs and corresponding nanocomposites are characterized using different criteria, such as gel content, viscosity and normalized storage modulus in the time sweep tests, nuclear magnetic resonance (NMR) signal line width, bound curative content and residual diene concentration. The combination of the above parameters appears to be sufficient to provide a clear description of the systems. The last part of the present study is devoted to find how the dispersion level of nanoclay and consequently the extent of crosslinking change the rubber like behaviour and the morphology of the prepared TPVs. Therefore, recently developed method named temperature scanning stress relaxation (TSSR) was used to estimate the rubber indices of TPVs and TPV nanocomposites. The mentioned method also successfully provided information about the extent of crosslinking reaction. It is shown that the rubber like behaviour of the blends containing 50wt% and 60wt% of EPDM in which morphological studies suggest the presence of the rubber droplets in vicinity of irregular shape rubber particles with a low level of interconnectivity, correlates with the rubber droplet size. Therefore, the nanoclay presence affects the rubber index values mainly through its effect on the size of the rubber droplets that controls the number of retraction points in the proposed buckling mechanism during the TSSR test. It should be mentioned that by increasing the EPDM content, the number of the droplet like domains decreases and more irregular shape rubber particles is formed. On the other hand, the direct relation between rubber index values and the crosslink density is observed only for those series of TPVs showing the fully developed extensive network between irregular shape rubber domains (blends containing 70wt% of EPDM). Hence, the nanoclay dispersion level influences the rubber like behaviour through its effect on the crosslink density. (Abstract shortened by UMI.).

  20. 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

  1. Phenol oxidation with hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Ramiez Cortina, R.C.; Hernadez Perez, I. [Univ. Autonoma Metropolitana - Azcapotzalco, Div. de CBI, Dept. de Energia, Azcapotzalco (Mexico); Ortiz Lozoya, C.E. [Univ. Autonoma Metropolitana - Azcapotzalco, Div. de CBI, Dept. de Energia, Azcapotzalco (Mexico)]|[Inst. Mexicano del Petroleo (Mexico); Alonso Gutierrez, M.S. [Inst. National Polytechnique, ENSCT, Lab. of Chimie Agro-Industrielle, Toulouse (France)

    2003-07-01

    In this work the process application of advanced oxidation is investigated with hydrogen peroxide, for the phenol destruction. The experiments were carried out in a glass reactor of 750 mL. Three phenol concentrations were studied (2000, 1000 and 500 ppm) being oxidized with H{sub 2}O{sub 2} (1, 2 and 3 M). The tests of oxidation had a reaction time of 48 h at ambient temperature and pressure. The phenol degradation was determined as COD at different reaction times and intermediate oxidation products were analyzed by chromatography. The results of this study show that it is possible to degrade phenol (1000 ppm) until 90% with H{sub 2}O{sub 2} 2M. Being achieved the best efficiency with a good molar relationship of H{sub 2}O{sub 2}/phenol. Intends a reaction outline in the degradation of the phenol. (orig.)

  2. 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.

  3. 7 CFR 58.431 - Hydrogen peroxide.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the U.S...

  4. Problem of the lithium peroxide thermal stability

    International Nuclear Information System (INIS)

    Nefedov, R A; Ferapontov, Yu A; Kozlova, N P

    2016-01-01

    The behavior of lithium peroxide and lithium peroxide monohydrate samples under heating in atmospheric air was studied by the method of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). It was found that in the temperature range of 32°C to 82°C the interaction of lithium peroxides and steam with the formation of lithium peroxide monohydrate occurs, which was confirmed chemically and by X-ray Single-qualitative analysis. It was experimentally found that lithium peroxide starts to decompose into the lithium oxide and oxygen in the temperature range of 340 ÷ 348°C. It was established that the resulting thermal decomposition of lithium oxide, lithium peroxide at the temperature of 422°C melts with lithium carbonate eutecticly. The manifestation of polymorphism was not marked(seen or noticed) under the heating of studied samples of lithium peroxide and lithium peroxide monohydrate in the temperature range of 25°C ÷ 34°C. (paper)

  5. 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.

  6. 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...

  7. Hydrogen peroxide treatment of TCE contaminated soil

    International Nuclear Information System (INIS)

    Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

    1993-01-01

    Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil

  8. Rearrangements of organic peroxides and related processes

    Directory of Open Access Journals (Sweden)

    Ivan A. Yaremenko

    2016-08-01

    Full Text Available This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately.

  9. [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.

  10. Effects of 35% Carbamide Peroxide Gel on Surface Roughness and Hardness of Composite Resins

    Directory of Open Access Journals (Sweden)

    F. Sharafeddin

    2010-03-01

    Full Text Available Objective: Bleaching agents may not be safe for dental materials. The purpose of this invitro study was to evaluate the effects of Opalescent Quick "in-office bleaching gel" containing 35% carbamide peroxide on the surface roughness and hardness of microfilled(Heliomolar and hybride (Spectrum TPH composite resins.Materials and Methods: Twenty specimens of Spectrum TPH composite resins and twenty Heliomolar composite resins were fabricated using a metallic ring (6.5 mm diameter and 2.5 mm thickness and light cured, then their surfaces were polished. Specimens of each composite resin were divided into two equal groups. Ten specimens of each type of composite were stored in water at 37°C as the control groups and 35% carbamide peroxide gel (Opalescence Quick as the other group for 30 minutes a week for 3 weeks. Then the specimens were subject to roughness and hardness tests.Results: This study revealed that using 35% carbamide peroxide bleaching gels had no significant effect on the surface roughness of Spectrum TPH "hybrid" and Heliomolar "microfilled" composite resins. The surface hardness of Spectrum TPH composite treated with the subject gel significantly increased compared to heliomolar, which had no significant change after treatment with this bleaching gel.Conclusion: If tooth color matching of the composite had been satisfactory after office bleaching with 35% carbamide peroxide gel, this material would have been acceptable because it has no adverse effect on Heliomolar and Spectrum TPH composite resins.

  11. 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 ...

  12. 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

  13. 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.)

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. The problem of peroxidation in radiolis logy

    International Nuclear Information System (INIS)

    Baraboj, V.A.; Chebotarev, E.E.

    1986-01-01

    A hypothesis is validated concerning the products of freeradical oxidation of lipids and the phenol compounds as a mediator of the stress-syndrome. The data are reviewed on activation of peroxidation under the effect of radiation, cytochemical agents, etc., secondarily stimulating the neurohumoral system function of homeostasis regulation. With the emotional-algesic and cold-stresses, the regulatory system stimulation is of primary, reflex, nature, but it secondarily promotes the peroxidation activation. The radiotoxins (of the quinoid and lipid nature) appearing in tissues under the effect of ionizing radiation, are smilar in structure and mechanism of action to peroxidation activation products formed under the effect of other stress-agents

  20. Inorganic precursor peroxides for antifouling coatings

    DEFF Research Database (Denmark)

    Olsen, S.M.; Pedersen, L.T.; Hermann, M.H.

    2009-01-01

    Modern antifouling coatings are generally based on cuprous oxide (Cu2O) and organic biocides as active ingredients. Cu2O is prone to bioaccumulation, and should therefore be replaced by more environmentally benign compounds when technically possible. However, cuprous oxide does not only provide...... antifouling properties, it is also a vital ingredient for the antifouling coating to obtain its polishing and leaching mechanism. In this paper, peroxides of strontium, calcium, magnesium, and zinc are tested as pigments in antifouling coatings. The peroxides react with seawater to create hydrogen peroxide...... matrix provides antifouling properties exceeding those of a similar coating based entirely on zinc oxide....

  1. 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

  2. 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)

  3. Peroxides and radiation impairment of oxidative phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Dovgii, I E; Akoev, I G

    1975-09-01

    An increase in the peroxidase activity of the mitochondria and a simultaneous rise in the amount of peroxide compounds, which are half lipid-like substances, are detected within the first 10 minutes after irradiation (1000 r). A mechanism of radiation impairment of oxidative phosphorylation is connected with the penetration of its inhibitors to the mitochondria due to the disturbed permeability of membranes affected by peroxides.

  4. Mechanisms of wet oxidation by hydrogen peroxide

    International Nuclear Information System (INIS)

    Baxter, R.A.

    1987-08-01

    A research programme is currently under way at BNL and MEL to investigate the possible use of Hydrogen Peroxide with metal ion catalysts as a wet oxidation treatment system for CEGB organic radioactive wastes. The published literature relating to the kinetics and mechanism of oxidation and decomposition reactions of hydrogen peroxide is reviewed and the links with practical waste management by wet oxidation are examined. Alternative wet oxidation systems are described and the similarities to the CEGB research effort are noted. (author)

  5. Hydrogen peroxide as a sustainable energy carrier: Electrocatalytic production of hydrogen peroxide and the fuel cell

    International Nuclear Information System (INIS)

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal–oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O 2 , which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  6. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

    Science.gov (United States)

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

    2012-11-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O 2 -reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O 2 , which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  7. Development of high-performance shielding material by heat curing method

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Toshimasa; Hirao, Yoshihiro; Hayashi, Takayuki; Okuno, Koichi; Sato, Osamu [National Maritime Research Institute, Ibaraki (Japan)

    2002-07-01

    A high-performance shielding material is developed by a heat curing method. It is mainly made of a thermosetting resin, lead powder, and a boron compound. To make the resin, a single functional monomer stearyl methacrylate (SMA) is used. To get good dispersion of lead and the boron compound in the resin, the viscosity of the SMA is increased by adding a small amount of a peroxide into the liquid monomer and heating up to the temperature of 100 .deg. C. Next, a peroxide, lead powder, a boron compound, a three functional monomer, and a curing accelerator are mixed into the viscous SMA. The mixture is cured in an atmosphere of nitrogen after removing bubbles using a vacuum pump. Measured properties of the cured material are as follows. The curing rate of SMA is 97 %. The density is kept 2.35 g/cm{sub 3} in the range from room temperature to 150 .deg. C. The weight-change measured by a thermogravimetry is 0.16 % in the range from room temperature to 200 .deg. C. Details of fragments in the gas released from the material is analyzed by a gas chromatography and a mass spectrometry. The hydrogen content of the material is 6.04x10 {sub 22} /cm{sub 3} . The shielding effect is calculated for a fission source by an Sn code ANISN. The shielding effect of the curing material is excellent. For example, concrete shield of a certain thickness can be replaced by the material having a thickness less than a half of concrete. Several samples of the material are irradiated at an irradiation equipment of the research reactor JRR-4 installed at Japan Atomic Energy Research Institute. At the 14{sub th} day after irradiating with the thermal neutron fluence of 6.6x10{sub 15} /cm{sub 2} , the radioactivity is less than one tenth of 75 Bq/g above which materials are regulated as the radioactive substance in Japan.

  8. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    International Nuclear Information System (INIS)

    HALGREN DL

    2008-01-01

    The 200 Area Effluent Treatment Facility (ETF) main treatment train includes the peroxide destruction module (PDM) where the hydrogen peroxide residual from the upstream ultraviolet light/hydrogen peroxide oxidation unit is destroyed. Removal of the residual peroxide is necessary to protect downstream membranes from the strong oxidizer. The main component of the PDM is two reaction vessels utilizing granular activated carbon (GAC) as the reaction media. The PDM experienced a number of operability problems, including frequent plugging, and has not been utilized since the ETF changed to groundwater as the predominant feed. The unit seemed to be underperforming in regards to peroxide removal during the early periods of operation as well. It is anticipated that a functional PDM will be required for wastewater from the vitrification plant and other future streams. An alternate media or methodology needs to be identified to replace the GAC in the PDMs. This series of bench scale tests is to develop information to support an engineering study on the options for replacement of the existing GAC method for peroxide destruction at the ETF. A number of different catalysts will be compared as well as other potential methods such as strong reducing agents. The testing should lead to general conclusions on the viability of different catalysts and identify candidates for further study and evaluation

  9. [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

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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 ...

  15. 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.

  16. 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.

  17. 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

  18. 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)

  19. 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

  20. 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

  1. 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.

  2. Ultraviolet curing of acrylated liquid natural rubber for surface coating application

    Directory of Open Access Journals (Sweden)

    Kannikar Kwanming

    2009-01-01

    Full Text Available Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR prior obtained from LNR with formic acid and hydrogen peroxide in the ratio of 2:1 by weight in toluene at 80oC for 6, 9, 12, 18, and 24 hrs. It was found that the percentage of acrylate grafted onto liquid natural rubber depended on the reaction time. Surface coating was performed by using acrylated liquid natural rubber and 1,6-hexanediol diacrylate (HDDA or tripropylene glycol diacrylate (TPGDA as a crosslinker and Irgarcure 184 or Irgarcure 651 as a photoinitiator under UV exposure for 30, 60, and 90 seconds. The hardness test of cured products was investigated using the Pencil hardness test at pencil level of 2B to 6H. It was found that the highest hardness of surface coating was at pencil level of 4H for the product using TPGDA and Irgacure 651 in the ratio of 80:10 parts per hundred of rubber (phr. The cured products were able to resist to 2% H2SO4 and distilled water for more than 24 hrs.

  3. 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.

  4. 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

  5. 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

  6. PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

    Science.gov (United States)

    Barrick, J.G.; Fries, B.A.

    1960-09-27

    A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

  7. Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

    Energy Technology Data Exchange (ETDEWEB)

    Sears, Jeremiah Matthew; Boyle, Timothy J.; Dean, Christopher J.

    2013-06-01

    This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference.

  8. 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

  9. 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.

  10. 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.

  11. Radiation induced peroxidation in model lipid systems

    International Nuclear Information System (INIS)

    Dahlan, K.Z.B.H.M.

    1981-08-01

    In the studies of radiation induced lipid peroxidation, lecithin-liposomes and aqueous micellar solutions of sodium linoleate (or linoleic acid) have been used as models of lipid membrane systems. The liposomes and aqueous linoleate micelles were irradiated in the presence of O 2 and N 2 O/O 2 (80/20 v/v). The peroxidation was initiated using gamma radiation from 60 Co radiation source and was monitored by measuring the increase in absorbance of conjugated diene at 232 nm and by the thiobarbituric acid (TBA) test. The oxidation products were also identified by GLC and GLC-MS analysis. (author)

  12. Precipitation of uranium concentrates by hydrogen peroxide

    International Nuclear Information System (INIS)

    Barbosa Filho, O.; Teixeira, L.A.C.

    1987-01-01

    An experimental study on the precipitation of uranyl peroxide (UO 4 x H 2 O) has been carried out in a laboratory scale. The objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. A factorial design was used to evaluate the effects of the initial pH, precipitation pH and H 2 O 2 /UO 2 2+ ratio upon the process. The responses were measured in terms of: efficiency of U precipitation, content of U in the precipitates, and distribution of impurities in the precipitates. (Author) [pt

  13. Uranium peroxide precipitate drying temperature relationships

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, C.; Dyck, B., E-mail: chick_rodgers@cameco.com [Cameco Corp., Saskatoon, SK (Canada)

    2010-07-01

    Cameco Corporation is in the process of revitalizing the mill at its Key Lake operation in northern Saskatchewan. The current Key Lake process employs ammonia stripping and ammonia precipitation. As part of the revitalization, the company is considering installing strong acid stripping in solvent extraction as used at its Rabbit Lake operation. This change would lead to using hydrogen peroxide for uranium precipitation. As part of the process evaluation, tests were carried out to study how changes in the temperature of an indirect fired dryer affected the properties of uranium peroxide [yellowcake] precipitate. This paper discusses the results of the test work, including the relationships between drying temperature and the following: (author)

  14. 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.

  15. 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)

  16. 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)

  17. 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

  18. 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

  19. Vitamin C Supplementation Reduces Peroxidative Damage without ...

    African Journals Online (AJOL)

    Objective: This study was designed to assess the effects of vitamin C supplementation on the lung function tests and peroxidative damage in asthmatic children. Methodology: Fifteen asthmatics aged between 8 - 14 years, all in the stable state were used in this study. Three millilitres of blood were drawn from the antecubital ...

  20. Relationship Between Calorie Restriction, Lipid Peroxidation ...

    African Journals Online (AJOL)

    In the brain of the caloric restricted rats, there was little or no change in the tGSH and GSH, although the GSSG and GSSG/GSH% ratio were increased significantly. These results suggest that aging of rats had been decelerated by caloric restriction due to the decrease in the peroxidative damage in the lungs and brain.

  1. 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.

  2. 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.

  3. Novel thermoplastic vulcanizates (TPVs based on silicone rubber and polyamide exploring peroxide cross-linking

    Directory of Open Access Journals (Sweden)

    K. Naskar

    2014-04-01

    Full Text Available Novel thermoplastic vulcanizates (TPVs based on silicone rubber (PDMS and polyamide (PA12 have been prepared by dynamic vulcanization process. The effect of dynamic vulcanization and influence of various types of peroxides as cross-linking agents were studied in detail. All the TPVs were prepared at a ratio of 50/50 wt% of silicone rubber and polyamide. Three structurally different peroxides, namely dicumyl peroxide (DCP, 3,3,5,7,7-pentamethyl 1,2,4-trioxepane (PMTO and cumyl hydroperoxide (CHP were taken for investigation. Though DCP was the best option for curing the silicone rubber, at high temperature it suffers from scorch safety. An inhibitor 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO was added with DCP to stabilize the radicals in order to increase the scorch time. Though CHP (hydroperoxide had higher half life time than DCP at higher temperature, it has no significant effect on cross-linking of silicone rubber. PMTO showed prolonged scorch safety and better cross-linking efficiency rather than the other two. TPVs of DCP and PMTO were made up to 11 minutes of mixing. Increased values of tensile strength and elongation at break of PMTO cross-linked TPV indicate the superiority of PMTO. Scanning electron micrographs correlate with mechanical properties of the TPVs. High storage modulus (E' and lower loss tangent value of the PMTO cross-linked TPV indicate the higher degree of cross-linking which is also well supported by the overall cross-link density value. Thus PMTO was found to be the superior peroxide for cross-linking of silicone rubber at high temperature.

  4. 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

  5. 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.

  6. 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.

  7. Microsomal lipid peroxidation as a mechanism of cellular damage. [Dissertation

    Energy Technology Data Exchange (ETDEWEB)

    Kornbrust, D.J.

    1979-01-01

    The NADPH/iron-dependent peroxidation of lipids in rat liver microsomes was found to be dependent on the presence of free ferrous ion and maintains iron in the reduced Fe/sup 2 +/ state. Chelation of iron by EDTA inhibited peroxidation. Addition of iron, after preincubation of microsomes in the absence of iron, did not enhance the rate of peroxidation suggesting that iron acts by initiating peroxidative decomposition of membrane lipids rather than by catalyzing the breakdown of pre-formed hydroperoxides. Liposomes also underwent peroxidation in the presence of ferrous iron at a rate comparable to intact microsomes and was stimulated by ascorbate. Carbon tetrachloride initiated lipid peroxidation in the absence of free metal ions. Rates of in vitro lipid peroxidation of microsomes and homogenates were found to vary widely between different tissues and species. The effects of paraquat on lipid peroxidation was also studied. (DC)

  8. 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...

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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

  14. Ionizing radiation and lipid peroxidation in human body

    International Nuclear Information System (INIS)

    Giubileo, Gianfranco

    1997-07-01

    Lipids are organic compounds constituting the living cells. Lipid molecules can be disassembled through peroxidative pathways and hydrocarbons can be bred as end-product of lipid peroxidation in vivo. Lipid peroxidation can be started by an indirect effect of ionizing radiation. So a radioinduced cellular damage in human body can be detected by monitoring the production of specific hydrocarbons

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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 ...

  20. Crystal structure of rubidium peroxide ammonia disolvate

    Directory of Open Access Journals (Sweden)

    Tobias Grassl

    2017-02-01

    Full Text Available The title compound, Rb2O2·2NH3, has been obtained as a reaction product of rubidium metal dissolved in liquid ammonia and glucuronic acid. As a result of the low-temperature crystallization, a disolvate was formed. To our knowledge, only one other solvate of an alkali metal peroxide is known: Na2O2·8H2O has been reported by Grehl et al. [Acta Cryst. (1995, C51, 1038–1040]. We determined the peroxide bond length to be 1.530 (11 Å, which is in accordance with the length reported by Bremm & Jansen [Z. Anorg. Allg. Chem. (1992, 610, 64–66]. One of the ammonia solvate molecules is disordered relative to a mirror plane, with 0.5 occupancy for the corresponding nitrogen atom.

  1. Functionalized Palladium Nanoparticles for Hydrogen Peroxide Biosensor

    Directory of Open Access Journals (Sweden)

    H. Baccar

    2011-01-01

    Full Text Available We present a comparison between two biosensors for hydrogen peroxide (H2O2 detection. The first biosensor was developed by the immobilization of Horseradish Peroxidase (HRP enzyme on thiol-modified gold electrode. The second biosensor was developed by the immobilization of cysteamine functionalizing palladium nanoparticles on modified gold surface. The amino groups can be activated with glutaraldehyde for horseradish peroxidase immobilization. The detection of hydrogen peroxide was successfully observed in PBS for both biosensors using the cyclic voltammetry and the chronoamperometry techniques. The results show that the limit detection depends on the large surface-to-volume ratio attained with palladium nanoparticles. The second biosensor presents a better detection limit of 7.5 μM in comparison with the first one which is equal to 75 μM.

  2. 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

  3. 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.

  4. 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.

  5. 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...

  6. 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)

  7. 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

  8. 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...

  9. 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.

  10. 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 ...

  11. 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 ...

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

    Science.gov (United States)

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

    2014-11-26

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

  13. Radiation curing of mixture of diallylphthalate prepolymer and vinyl monomer, 11

    International Nuclear Information System (INIS)

    Gotoda, Masao; Yagi, Toshiaki; Yoshizawa, Iwao; Okugawa, Hideo.

    1975-01-01

    Preparation of Wood-Polymer Composite (WPC) piled plywood for flooring, was attempted by electron beam irradiation of American Hemlock veneer, impregnated with low molecular weight diallylphthalate prepolymer (DAPsub(p).L)/vinyl monomer mixtures, in comparison with that by thermal curing reported previously. For the improvement of the mechanical properties of WPC piled plywood, 5-15 parts of low molecular weight polyvinylacetate (PVAc) was added to DAPsub(p).L/methyl acrylate/hydroxyethyl acrylate/benzoyl peroxide (50/40/10/2) mixture. The addition of PVAc did not give much influence to the degree of impregnation in the veneer and to the curability by electron beam irradiation. As to the resistance to hot and cold cycle test, WPC piled plywood, prepared by the resin containing 5 parts of PVAc gave the best results. As a general conclusion, due to the superior mechanical properties, the WPC piled plywood processed by electron beam irradiation is suitable for flooring use. (author)

  14. 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)

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. Lipid Peroxidation and Antioxidant Status in Preeclampsia

    Directory of Open Access Journals (Sweden)

    Rokeya Begum

    2011-07-01

    Full Text Available Background: Preeclampsia is the most common and major medical complication of pregnancy with a high incidence of maternal and foetal morbidity and mortality. During pregnancy abnormally increased lipid peroxidation and free radical formation as well as significantly decreased antioxidants production in maternal blood may lead to pathogenesis of preeclampsia. So, we designed this study as little information is known about lipid peroxidation and antioxidant level in preeclampsia. Objectives: To assess the serum malondialdehyde (MDA level as a lipid peroxidation product and vitamin E (antioxidant level in women with preeclampsia as well as in normal pregnancy and to compare the values. Materials and Methods: The study was conducted on 60 women aged from 25 to 35 years in the department of Biochemistry, Budi Kemuliaan Maternity Hospital (BKMH in Jakarta during the period April to July 2004. Twenty were normal pregnant women and 20 were preeclamptic patients. For comparison age matched 20 apparently healthy nonpregnant women were included in the study. The study subjects were selected from outpatient department (OPD of Obstetrics and Gynaecology of BKMH in Jakarta. Serum MDA (lipid peroxidation product level was measured by thiobarbituric acid reactive substances assay (TBRAS method and vitamin E was estimated spectroflurometrically. Data were analyzed by unpaired Student’s t test between the groups by using SPSS version 12. Results: The mean serum MDA levels were significantly higher in normal pregnancy and also in preeclampsia than that of nonpregnant control group women (p<0.001. Again the serum MDA levels were significantly higher in preeclampsia than that of normal pregnant women (p<0.001. The serum vitamin E levels were significantly lower in preeclampsia and also in normal pregnancy than that of nonpregnant control women (p<0.001. Moreover, the serum vitamin E levels were significantly lower in preeclampsia compared to that of normal

  20. 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

  1. 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)

  2. 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.

  3. 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.

  4. 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)

  5. 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.

  6. Hydrogen peroxide stabilization in one-dimensional flow columns

    Science.gov (United States)

    Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

    2011-09-01

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

  7. 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.

  8. 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.

  9. Alkaline Peroxide Delignification of Corn Stover

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Ashutosh [Biosciences; Katahira, Rui [National; Donohoe, Bryon S. [Biosciences; Black, Brenna A. [National; Pattathil, Sivakumar [Complex; Stringer, Jack M. [National; Beckham, Gregg T. [National

    2017-05-30

    Selective biomass fractionation into carbohydrates and lignin is a key challenge in the conversion of lignocellulosic biomass to fuels and chemicals. In the present study, alkaline hydrogen peroxide (AHP) pretreatment was investigated to fractionate lignin from polysaccharides in corn stover (CS), with a particular emphasis on the fate of the lignin for subsequent valorization. The influence of peroxide loading on delignification during AHP pretreatment was examined over the range of 30-500 mg H2O2/g dry CS at 50 degrees C for 3 h. Mass balances were conducted on the solid and liquid fractions generated after pretreatment for each of the three primary components, lignin, hemicellulose, and cellulose. AHP pretreatment at 250 mg H2O2/g dry CS resulted in the pretreated solids with more than 80% delignification consequently enriching the carbohydrate fraction to >90%. Two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy of the AHP pretreated residue shows that, under high peroxide loadings (>250 mg H2O2/g dry CS), most of the side chain structures were oxidized and the aryl-ether bonds in lignin were partially cleaved, resulting in significant delignification of the pretreated residues. Gel permeation chromatography (GPC) analysis shows that AHP pretreatment effectively depolymerizes CS lignin into low molecular weight (LMW) lignin fragments in the aqueous fraction. Imaging of AHP pretreated residues shows a more granular texture and a clear lamellar pattern in secondary walls, indicative of layers of varying lignin removal or relocalization. Enzymatic hydrolysis of this pretreated residue at 20 mg/g of glucan resulted in 90% and 80% yields of glucose and xylose, respectively, after 120 h. Overall, AHP pretreatment is able to selectively remove more than 80% of the lignin from biomass in a form that has potential for downstream valorization processes and enriches the solid pulp into a highly digestible material.

  10. Engineering bacterial motility towards hydrogen-peroxide.

    Science.gov (United States)

    Virgile, Chelsea; Hauk, Pricila; Wu, Hsuan-Chen; Shang, Wu; Tsao, Chen-Yu; Payne, Gregory F; Bentley, William E

    2018-01-01

    Synthetic biologists construct innovative genetic/biological systems to treat environmental, energy, and health problems. Many systems employ rewired cells for non-native product synthesis, while a few have employed the rewired cells as 'smart' devices with programmable function. Building on the latter, we developed a genetic construct to control and direct bacterial motility towards hydrogen peroxide, one of the body's immune response signaling molecules. A motivation for this work is the creation of cells that can target and autonomously treat disease, the latter signaled by hydrogen peroxide release. Bacteria naturally move towards a variety of molecular cues (e.g., nutrients) in the process of chemotaxis. In this work, we engineered bacteria to recognize and move towards hydrogen peroxide, a non-native chemoattractant and potential toxin. Our system exploits oxyRS, the native oxidative stress regulon of E. coli. We first demonstrated H2O2-mediated upregulation motility regulator, CheZ. Using transwell assays, we showed a two-fold increase in net motility towards H2O2. Then, using a 2D cell tracking system, we quantified bacterial motility descriptors including velocity, % running (of tumble/run motions), and a dynamic net directionality towards the molecular cue. In CheZ mutants, we found that increased H2O2 concentration (0-200 μM) and induction time resulted in increased running speeds, ultimately reaching the native E. coli wild-type speed of ~22 μm/s with a ~45-65% ratio of running to tumbling. Finally, using a microfluidic device with stable H2O2 gradients, we characterized responses and the potential for "programmed" directionality towards H2O2 in quiescent fluids. Overall, the synthetic biology framework and tracking analysis in this work will provide a framework for investigating controlled motility of E. coli and other 'smart' probiotics for signal-directed treatment.

  11. 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.

  12. Effect of gamma-radiation on major aroma compounds and vanillin glucoside of cured vanilla beans (Vanilla planifolia)

    International Nuclear Information System (INIS)

    Salmah Moosa; Seri Chempaka Mohd Yusof; Ruzalina Bahrin; Maizatul Akmam Mohd Nasir

    2014-01-01

    Radiation processing of food materials by gamma-radiation is a well established method for microbial decontamination and insect disinfestation. Irradiation of spices at doses ranging from 10 to 30 kGy has been reported to result in complete elimination of microorganisms with negligible changes in the flavour quality. The effect of gamma-radiation on microflora and vanillin content of cured vanilla beans in the dose range of 5-50 kGy has been investigated, but its effect on other major aroma compounds and vanillin glucoside (vanillin aroma precursor) remaining after curing have not been studied so far. Vanillin (4-hydroxy-3-methoxybenzaldehyde) is one such compound used as a flavouring agent and as a dietary component. It is the major component of natural vanilla, which is one of the most widely used and important flavouring materials throughout the world. Vanillin is an antioxidant capable of protecting membrane against lipid peroxidation and DNA against strand breaks induced by reactive oxygen species. The present work was aimed to study the effect of gamma-radiation processing on the major aroma compounds of cured vanilla beans and also to investigate possible enhancement in vanillin content by the radiolytic breakdown of vanillin glucoside present already. Cured vanilla beans were irradiated (5, 10, 15, 20 and 30 kGy) and the vanillin content of control and irradiated samples were analysed, respectively for a possible enhancement of vanillin content by radiolysis of vanillin glucoside. Radiolytic breakdown of glycosidic precursors of aroma constituents and consequent release of free aroma was shown to result in the enhancement of aroma quality of these products. Since a considerable amount of vanillin exists as its glycosidic precursor in cured vanilla pods, a possible enhancement in yield of vanillin by radiation processing is thus expected. Hence the highly stable oxygen-carbon linkage between vanillin and glucose limits the possible enhancement of aroma

  13. Peroxide coordination of tellurium in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mikhaylov, Alexey A.; Medvedev, Alexander G. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel); Churakov, Andrei V.; Grishanov, Dmitry A.; Prikhodchenko, Petr V. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Lev, Ovadia [The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel)

    2016-02-15

    Tellurium-peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH{sub 4}){sub 4}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2} (1) and (NH{sub 4}){sub 5}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH).1.28 H{sub 2}O.0.72 H{sub 2}O{sub 2} (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single-crystal and powder X-ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2}]{sup 4-}. The structure of 2 consists of an unsymmetrical [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH)]{sup 5-} anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te{sub 2}(μ-OO){sub 2}(μ-O) fragment with one μ-oxo- and two μ-peroxo bridging groups. {sup 125}Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3-40 %wt H{sub 2}O{sub 2} and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium-peroxide coordination in any aqueous system and the first report of inorganic tellurium-peroxo complexes. General features common to all reported p-block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. 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

  15. Effect of cadmium chloride on hepatic lipid peroxidation in mice

    DEFF Research Database (Denmark)

    Andersen, H R; Andersen, O

    1988-01-01

    Intraperitoneal administration of cadmium chloride to 8-12 weeks old CBA-mice enhanced hepatic lipid peroxidation. A positive correlation between cadmium chloride dose and level of peroxidation was observed in both male and female mice. A sex-related difference in mortality was not observed...... but at a dose of 25 mumol CdCl2/kg the level of hepatic lipid peroxidation was higher in male mice than in female mice. The hepatic lipid peroxidation was not increased above the control level in 3 weeks old mice, while 6 weeks old mice responded with increased peroxidation as did 8-12 weeks old mice....... The mortality after an acute toxic dose of cadmium chloride was the same in the three age groups. Pretreatment of mice with several low intraperitoneal doses of cadmium chloride alleviated cadmium induced mortality and lipid peroxidation. The results demonstrate both age dependency and a protective effect...

  16. Non-isothermal curing kinetics and physical properties of MMT-reinforced unsaturated polyester (UP) resins

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, María A., E-mail: angelesvh@yahoo.com [Tecnológico de Estudios Superiores de Ecatepec, Av. Tecnológico S/N, Valle de Anáhuac, 55210 Ecatepec de Morelos (Mexico); Vázquez, H. [Universidad Autónoma Metropolitana-Iztapalapa, Departamento de Física, Av. San Rafael Atlixco 186, col. Vicentina, Mexico, D.F. 09340 (Mexico); Guthausen, G. [KIT, Pro2NMR at MVM and IBG, Karlsruhe (Germany)

    2015-07-10

    Highlights: • Non-isothermal DSC analysis results have shown that the addition of MMT to a UP resin produces a delay in the cure reaction. • The shape of experimental heat-flow DSC curves showed two exothermic peaks for all the samples at different heating rates. • The overall kinetic analysis was performed by isoconversional methods. • It was found that the dependence of the activation energy (E{sub a}) on degree of reaction (α) is complex. - Abstract: Cure behavior of unsaturated polyester (UP)/montmorillonite (MMT)/methyl ethyl ketone peroxide (MEKP)/cobalt octoate intercalated nanocomposites with various MMT loadings was investigated by dynamic differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). UP/MMT nanocomposites were prepared by sequential mixing. Non-isothermal DSC curves were obtained by applying heating rates ranging from 5 to 20 °C/min. They presented two exothermic peaks, which should correspond to two independent cure reactions. The effective activation energy E{sub a}, was determined by applying both the Kissinger’s and Starink’s methods. The results showed slightly higher activation energy for nanocomposites, except for UP/10-MMT. It was found that the dependence of E{sub a} on α is complex. All the systems in this study fitted Sesták–Berggren (SB) model in overall reaction controlled kinetics and the corresponding model parameters, n, m, A were obtained, but it was insufficient in depicting the complex reaction kinetics. Transmission electron microscopy data support the formation of a partially delaminated nanocomposite material. UP and nanocomposites showed similar behavior on thermal stability.

  17. Effects of Grapefruit Seed Extract on Oxidative Stability and Quality Properties of Cured Chicken Breast.

    Science.gov (United States)

    Kang, Su-Tae; Son, Hee-Kyoung; Lee, Hyun-Joo; Choi, Jung-Seok; Choi, Yang-Il; Lee, Jae-Joon

    2017-01-01

    This study investigated the antioxidative and functional effects of a curing agent containing grapefruit seed extract (GSE) on the quality and storage characteristics of chicken breast. The total polyphenol and total flavonoid contents of GSE were 45.06 mg/g and 36.06 mg/g, respectively. The IC 50 value of 2,2-diphenyl-1-picrylhydrazyl hydroxyl scavenging of GSE was 333.33 μg/mL. The chicken breast comprised six groups: no-treatment (N), 0.2% ascorbic acid + 70 ppm sodium nitrite (C), 0.05% GSE (G0.05), 0.1% GSE (G0.1), 0.3% GSE (G0.3), and 0.5% GSE (G0.5). The pH and cooking loss of cured chicken breast decreased with increasing GSE levels, and the water holding capacity increased with increasing GSE levels. The hardness and chewiness of GSE-treated chicken breast were higher than those of N and C. Hunter's L and a color values increased significantly after GSE addition. Moreover, 0.1% GSE (G0.1) increased the flavor and total acceptability scores. The 2-thiobarbituric acid and volatile basic nitrogen values of the 0.5% GSE group decreased significantly compared with those of C group. Total microbial counts of GSE-treated chicken breast were higher than those of C, but that lower than those of N. Adding GSE to chicken breast delayed lipid peroxidation and had antimicrobial effects during cold storage. GSE improved shelf life and palatability; therefore, it could be used as a natural antioxidant and functional curing agent ingredient in meat products.

  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. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Hydrogen peroxide probes directed to different cellular compartments.

    OpenAIRE

    Mikalai Malinouski; You Zhou; Vsevolod V Belousov; Dolph L Hatfield; Vadim N Gladyshev

    2011-01-01

    Background Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells. Principal Findings Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular ...

  8. Radiation-induced peroxidation of egg lecithin liposomes

    International Nuclear Information System (INIS)

    Bisby, R.H.; Cundall, R.B.; Tomaszewski, K.E.; Coleman, M.H.; Gould, G.

    1983-01-01

    Peroxidation of multilamellar vesicles of egg lecithin was measured following γ-irradiation of oxygen saturated suspensions. The addition of hydroxyl radical scavengers and the enzymes superoxide dismutase and catalase was used to show that hydroxyl radicals were the major species initiating peroxidation. Superoxide radicals were found to be much less effective initiators of peroxidation. Trolox C, a water soluble analogue of vitamin E, was found to act as an efficient antioxidant in this system. (author)

  9. 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

  10. 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.

  11. 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

  12. Precipitation of uranium concentrates by hydrogen peroxide

    International Nuclear Information System (INIS)

    Barbosa Filho, O.

    1986-12-01

    An experimental study on the (UO 4 .xH 2 ) uranyl peroxide precipitation from a uranium process strip solution is presented. The runs were performed in a batch reactor, in laboratory scale. The main objective was to assess the possibility of the peroxide route as an alternative to a conventional ammonium diuranate process. The chemical composition of process solution was obtained. The experiments were conducted according to a factorial design, aiming to evaluate the effects of initial pH, precipitation pH and H 2 O 2 /UO 2 2+ ratio upon the process. The responses were measured in terms of the efficiency of U precipitation, the content of U in the precipitates and the distribution of impurities in the precipitates. The results indicated that the process works is satisfactory on the studied conditions and depending on conditions, it is possible to achieve levels of U precipitation efficiency greater than 99.9% in reaction times of 2 hours. The precipitates reach grades around 99% U 3 O 8 after calcination (900 0 C) and impurities fall below the limit for penalties established by the ASTM and the Allied Chemical Standards. The precipitates are composed of large aggregates of crystals of 1-4 μm, are fast settling and filtering, and are free-flowing when dry. (Author) [pt

  13. Antioxidant effect of bisphosphonates and simvastatin on chondrocyte lipid peroxidation

    International Nuclear Information System (INIS)

    Dombrecht, E.J.; De Tollenaere, C.B.; Aerts, K.; Cos, P.; Schuerwegh, A.J.; Bridts, C.H.; Van Offel, J.F.; Ebo, D.G.; Stevens, W.J.; De Clerck, L.S.

    2006-01-01

    The objective of this study was to evaluate the effect of bisphosphonates (BPs) and simvastatin on chondrocyte lipid peroxidation. For this purpose, a flow cytometrical method using C11-BODIPY 581/591 was developed to detect hydroperoxide-induced lipid peroxidation in chondrocytes. Tertiary butylhydroperoxide (t-BHP) induced a time and concentration dependent increase in chondrocyte lipid peroxidation. Addition of a Fe 2+ /EDTA complex to t-BHP or hydrogen peroxide (H 2 O 2 ) clearly enhanced lipid peroxidation. The lipophilic simvastatin demonstrated a small inhibition in the chondrocyte lipid peroxidation. None of three tested BPs (clodronate, pamidronate, and risedronate) had an effect on chondrocyte lipid peroxidation induced by t-BHP. However, when Fe 2+ /EDTA complex was added to t-BHP or H 2 O 2 , BPs inhibited the lipid peroxidation process varying from 25% to 58%. This study demonstrates that BPs have antioxidant properties as iron chelators, thereby inhibiting the chondrocyte lipid peroxidation. These findings add evidence to the therapeutic potential of bisphosphonates and statins in rheumatoid arthritis

  14. A survey of chemicals inducing lipid peroxidation in biological systems.

    Science.gov (United States)

    Kappus, H

    1987-01-01

    A great number of drugs and chemicals are reviewed which have been shown to stimulate lipid peroxidation in any biological system. The underlying mechanisms, as far as known, are also dealt with. Lipid peroxidation induced by iron ions, organic hydroperoxides, halogenated hydrocarbons, redox cycling drugs, glutathione depleting chemicals, ethanol, heavy metals, ozone, nitrogen dioxide and a number of miscellaneous compounds, e.g. hydrazines, pesticides, antibiotics, are mentioned. It is shown that lipid peroxidation is stimulated by many of these compounds. However, quantitative estimates cannot be given yet and it is still impossible to judge the biological relevance of chemical-induced lipid peroxidation.

  15. Hydrogen Peroxide Probes Directed to Different Cellular Compartments

    Science.gov (United States)

    Malinouski, Mikalai; Zhou, You; Belousov, Vsevolod V.; Hatfield, Dolph L.; Gladyshev, Vadim N.

    2011-01-01

    Background Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells. Principal Findings Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events. Conclusions We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells. PMID:21283738

  16. Hydrogen peroxide probes directed to different cellular compartments.

    Directory of Open Access Journals (Sweden)

    Mikalai Malinouski

    2011-01-01

    Full Text Available Controlled generation and removal of hydrogen peroxide play important roles in cellular redox homeostasis and signaling. We used a hydrogen peroxide biosensor HyPer, targeted to different compartments, to examine these processes in mammalian cells.Reversible responses were observed to various redox perturbations and signaling events. HyPer expressed in HEK 293 cells was found to sense low micromolar levels of hydrogen peroxide. When targeted to various cellular compartments, HyPer occurred in the reduced state in the nucleus, cytosol, peroxisomes, mitochondrial intermembrane space and mitochondrial matrix, but low levels of the oxidized form of the biosensor were also observed in each of these compartments, consistent with a low peroxide tone in mammalian cells. In contrast, HyPer was mostly oxidized in the endoplasmic reticulum. Using this system, we characterized control of hydrogen peroxide in various cell systems, such as cells deficient in thioredoxin reductase, sulfhydryl oxidases or subjected to selenium deficiency. Generation of hydrogen peroxide could also be monitored in various compartments following signaling events.We found that HyPer can be used as a valuable tool to monitor hydrogen peroxide generated in different cellular compartments. The data also show that hydrogen peroxide generated in one compartment could translocate to other compartments. Our data provide information on compartmentalization, dynamics and homeostatic control of hydrogen peroxide in mammalian cells.

  17. Synthesis and thermal properties of strontium and calcium peroxides

    Science.gov (United States)

    Philipp, Warren H.; Kraft, Patricia A.

    1989-01-01

    A practical synthesis and a discussion of some chemical properties of pure strontium peroxide and calcium peroxide are presented. The general synthesis of these peroxides involves precipitation of their octahydrates by addition of H2O2 to aqueous ammoniacal Sr(NO3)2 or CaCl2. The octahydrates are converted to the anhydrous peroxides by various dehydration techniques. A new x-ray diffraction powder pattern for CaO2 x 8H2O is given from which lattice parameters a=6.212830 and c=11.0090 were calculated on the basis of the tetragonal crystal system.

  18. Effect of antioxidants and silicates on peroxides in povidone.

    Science.gov (United States)

    Narang, Ajit S; Rao, Venkatramana M; Desai, Divyakant S

    2012-01-01

    Reactive peroxides in povidone often lead to degradation of oxidation-labile drugs. To reduce peroxide concentration in povidone, the roles of storage conditions, antioxidants, and silicates were investigated. Povidone alone and its physical mixtures with ascorbic acid, propyl gallate, sodium sulfite, butylated hydroxyanisole (BHA), or butylated hydroxytoluene (BHT) were stored at 25 °C and 40 °C, at 11%, 32%, and 50% relative humidity. In addition, povidone solution in methanol was equilibrated with silicates (silica gel and molecular sieves), followed by solvent evaporation to recover povidone powder. Peroxide concentrations in povidone were measured. The concentration of peroxides in povidone increased under very-low-humidity storage conditions. Among the antioxidants, ascorbic acid, propyl gallate, and sodium sulfite reduced the peroxide concentration in povidone, whereas BHA and BHT did not. Water solubility appeared to determine the effectiveness of antioxidants. Also, some silicates significantly reduced peroxide concentration in povidone without affecting its functionality as a tablet binder. Porosity of silicates was critical to their ability to reduce the peroxide concentration in povidone. A combination of these approaches can reduce the initial peroxide concentration in povidone and minimize peroxide growth under routine storage conditions. Copyright © 2011 Wiley-Liss, Inc.

  19. 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)

  20. 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....

  1. 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.

  2. 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)

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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)

  8. 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.

  9. 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

  10. 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)

  11. 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.

  12. 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

  13. 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.

  14. Hydrogen peroxide decomposition kinetics in aquaculture water

    DEFF Research Database (Denmark)

    Arvin, Erik; Pedersen, Lars-Flemming

    2015-01-01

    during the HP decomposition. The model assumes that the enzyme decay is controlled by an inactivation stoichiometry related to the HP decomposition. In order to make the model easily applicable, it is furthermore assumed that the COD is a proxy of the active biomass concentration of the water and thereby......Hydrogen peroxide (HP) is used in aquaculture systems where preventive or curative water treatments occasionally are required. Use of chemical agents can be challenging in recirculating aquaculture systems (RAS) due to extended water retention time and because the agents must not damage the fish...... reared or the nitrifying bacteria in the biofilters at concentrations required to eliminating pathogens. This calls for quantitative insight into the fate of the disinfectant residuals during water treatment. This paper presents a kinetic model that describes the HP decomposition in aquaculture water...

  15. Hydrogen peroxide biosensor based on titanium oxide

    Science.gov (United States)

    Halim, Nur Hamidah Abdul; Heng, Lee Yook; Hashim, Uda

    2015-09-01

    In this work, a biosensor utilizing modified titania, TiO2 particles using aminopropyl-triethoxy-silane, (APTS) for developing hydrogen peroxide biosensor is presented. The surface of Ti-APTS particles is used as a support for hemoglobin immobilization via covalent bonding. The performance of the biosensor is determined by differential pulse voltammetry. The linear response was observed at the reduction current of redox mediator probe [FeCN6]3-/4- at potential between 0.22 V to 0.24 V. The preliminary result for electrochemistry study on this modified electrode is reported. The preliminary linear range is obtained from 1×10-2 M to 1×10-8 M.

  16. Hydrogen Peroxide Storage in Small Sealed Tanks

    International Nuclear Information System (INIS)

    Whitehead, J.

    1999-01-01

    Unstabilized hydrogen peroxide of 85% concentration has been prepared in laboratory quantities for testing material compatibility and long term storage on a small scale. Vessels made of candidate tank and liner materials ranged in volume from 1 cc to 2540 cc. Numerous metals and plastics were tried at the smallest scales, while promising ones were used to fabricate larger vessels and liners. An aluminum alloy (6061-T6) performed poorly, including increasing homogeneous decay due to alloying elements entering solution. The decay rate in this high strength aluminum was greatly reduced by anodizing. Better results were obtained with polymers, particularly polyvinylidene fluoride. Data reported herein include ullage pressures as a function of time with changing decay rates, and contamination analysis results

  17. Lipid peroxidation and ascorbic acid levels in Nigeria children with ...

    African Journals Online (AJOL)

    This study was undertaken to establish data on the roles of lipid peroxidation and ascorbic acid in the pathology of malaria in Nigeria children. We measured the levels of malondialdehyde (MDA), a marker of lipid peroxidation and ascorbic acid in the plasma of 406 parasitaemic and 212 non-parasitaemic Nigerian children.

  18. effect of hydrogen peroxide and thiourea on dormancy breaking of ...

    African Journals Online (AJOL)

    ACSS

    the hydrogen peroxide (H2O2) (Claassens and. Vreugdenhil, 2000; Suttle, 2004). Hence, the objective of this study was to evaluate the effects of hydrogen peroxide and thiourea on dormancy and sprouting of potato microtubers and field grown tubers is described. MATERIELS AND METHODS. Production of microtubers.

  19. Plasma lipid peroxidation and progression of disability in multiple sclerosis

    NARCIS (Netherlands)

    Koch, M.; Mostert, J.; Arutjunyan, A. V.; Stepanov, M.; Teelken, A.; Heersema, D.; De Keyser, J.

    Oxidative stress has been implicated in the pathophysiology of multiple sclerosis (MS), but its relation to disease progression is uncertain. To evaluate the relationship of plasma lipid peroxidation with progression of disability in MS, we measured blood plasma fluorescent lipid peroxidation

  20. Propylene epoxydation with hydrogen peroxide in acidic conditions

    NARCIS (Netherlands)

    Kertalli, E.; Rijnsoever, L.S.; Paunovic, V.; Schouten, J.C.; Neira d'Angelo, M.F.; Nijhuis, T.A.

    2016-01-01

    In the present work, the epoxidation of propylene with hydrogen peroxide in the presence of acids and halides is studied. The presence of acids and halides is indispensable for increasing the selectivity of the direct synthesis of hydrogen peroxide, the first step of the direct propylene oxide

  1. Chromium-induced accumulation of peroxide content, stimulation of ...

    African Journals Online (AJOL)

    Chromium (Cr)-induced oxidative damage and changes in contents of chlorophyll, protein, peroxide and malondialdehyde (MDA) and activities of enzymatic antioxidants were investigated in 4-day-old green gram (Vigna radiata L. cv. Wilczek) seedlings. Cr increased the contents of peroxide and MDA but decreased the ...

  2. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    An increase in produced hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase

  3. A hydrogen peroxide sensor for exhaled breath measurement

    NARCIS (Netherlands)

    Dam, T.V.A.; Olthuis, Wouter; Bergveld, Piet

    2005-01-01

    An increase in hydrogen peroxide concentration in exhaled breath (EB) of patients, who suffer from some diseases related to the lung function, has been observed and considered as a reliable indicator of lung diseases. In the EB of these patients, hydrogen peroxide is present in the vapour phase

  4. Direct synthesis of hydrogen peroxide in a microreactor

    NARCIS (Netherlands)

    Paunovic, V.; Schouten, J.C.; Nijhuis, T.A.

    2014-01-01

    The direct synthesis of hydrogen peroxide in a microreactor is a safe and efficient process. Conventionally, hydrogen peroxide is produced using the anthraquinone autooxidation process, which is rather complex and can only be performed cost-effectively on a large scale. As a result, hydrogen

  5. The evaluation of hydrogen peroxide bleaching of Gonometa ...

    African Journals Online (AJOL)

    The effect of hydrogen peroxide bleaching on Gonometa postica silk and the influence that temperature, pH and time duration had on hydrogen peroxide release , colour change, breaking load and stiffness were determined. The best bleaching (81 delta E) of the Gonometa postica silk fabric was obtained with 60 minutes ...

  6. 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

  7. 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.

  8. 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...

  9. 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)

  10. Radiation effect on lipid peroxide content of spices

    International Nuclear Information System (INIS)

    Kaneko, Nobutada; Ito, Hitoshi; Ishigaki, Isao

    1990-01-01

    To evaluate the radiation-induced deterioration of lipid in spices, peroxide value, iodine value and acid value were measured after extraction by chloroform. Peroxide values of black pepper and white pepper were not increased by gamma-irradiation with doses below 30 kGy and gradually increased at higher dose up to 80 kGy in this study. On contrary, peroxide values of clove and rosemary increased rather quickly below 20 kGy of gamma-irradiation, and they became stationary at higher dose. Iodine values and acid values had relationship with peroxide values on each kind of spices. On the storage study of irradiated spices, peroxide values decreased quickly during 20 days storage as same as nonirradiated spices, and it became stationary after 20 to 50 days storage at 30degC. Enhancement of oxidized deterioration were not observed even higher irradiation doses up to 80 kGy in this study. (author)

  11. Determination of active oxygen content in rare earth peroxides

    International Nuclear Information System (INIS)

    Queiroz, Carlos A.S.; Abrao, Alcidio

    1993-01-01

    The content of active oxygen in rare earth peroxides have been determined after the dissolution of the samples with hydrocloridic acid in the presence of potassium iodide. The free generated iodine is titrated with sodium thiosulfate using starch as indicator. The oxidation of iodide to the free iodine indicates the presence of a higher valence state rare earth oxide, until now specifically recognized for the oxides of cerium (Ce O 2 ), praseodymium (Pr 6 O 1 1) and terbium (TB 4 O 7 ). recently the authors synthesized a new series of rare earth compounds, the peroxides. These new compounds were prepared by precipitating the rare earth elements complexed with carbonate ion by addition of hydrogen peroxide. the authors demonstrated that all rare earth elements, once solubilized by complexing with carbonate ion, are quantitatively precipitated as peroxide by addition of hydrogen peroxide. (author)

  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. PEROXIDE DESTRUCTION TESTING FOR THE 200 AREA EFFLUENT TREATMENT FACILITY

    International Nuclear Information System (INIS)

    Halgren, D.L.

    2010-01-01

    The hydrogen peroxide decomposer columns at the 200 Area Effluent Treatment Facility (ETF) have been taken out of service due to ongoing problems with particulate fines and poor destruction performance from the granular activated carbon (GAC) used in the columns. An alternative search was initiated and led to bench scale testing and then pilot scale testing. Based on the bench scale testing three manganese dioxide based catalysts were evaluated in the peroxide destruction pilot column installed at the 300 Area Treated Effluent Disposal Facility. The ten inch diameter, nine foot tall, clear polyvinyl chloride (PVC) column allowed for the same six foot catalyst bed depth as is in the existing ETF system. The flow rate to the column was controlled to evaluate the performance at the same superficial velocity (gpm/ft 2 ) as the full scale design flow and normal process flow. Each catalyst was evaluated on peroxide destruction performance and particulate fines capacity and carryover. Peroxide destruction was measured by hydrogen peroxide concentration analysis of samples taken before and after the column. The presence of fines in the column headspace and the discharge from carryover was generally assessed by visual observation. All three catalysts met the peroxide destruction criteria by achieving hydrogen peroxide discharge concentrations of less than 0.5 mg/L at the design flow with inlet peroxide concentrations greater than 100 mg/L. The Sud-Chemie T-2525 catalyst was markedly better in the minimization of fines and particle carryover. It is anticipated the T-2525 can be installed as a direct replacement for the GAC in the peroxide decomposer columns. Based on the results of the peroxide method development work the recommendation is to purchase the T-2525 catalyst and initially load one of the ETF decomposer columns for full scale testing.

  17. Polypropylene/ethylene-propylene rubber (PP/EPR blends for the automotive industry: Basic correlations between EPR-design and shrinkage

    Directory of Open Access Journals (Sweden)

    G. D. Potter

    2014-04-01

    Full Text Available The influence of the phase morphology on the shrinkage of injection molded plates from reactor based PP/EPR blends was investigated using a model series. The morphology of the dispersed phase – in terms of size and shape of the rubber particles as determined from scanning electron microscopy (SEM – was found to correlate fairly well with the shrinkage determined in the flow and transverse direction of injection molded plates. In this respect it turned out to be elementary to consider the anisotropy of the particles rather than their average size alone. Additionally, the effect of the EPR design on the coefficient of linear thermal expansion (CLTE was evaluated and brought into a relationship with the blend morphology.

  18. 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

  19. 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

  20. 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)

  1. 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.

  2. 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 ...

  3. 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...

  4. 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...

  5. 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

  6. 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 ...

  7. 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 ...

  8. 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)

  9. 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.

  10. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  11. Kinetics of Platinum-Catalyzed Decomposition of Hydrogen Peroxide

    Science.gov (United States)

    Vetter, Tiffany A.; Colombo, D. Philip, Jr.

    2003-07-01

    CIBA Vision Corporation markets a contact lens cleaning system that consists of an AOSEPT disinfectant solution and an AOSEPT lens cup. The disinfectant is a buffered 3.0% m/v hydrogen peroxide solution and the cup includes a platinum-coated AOSEPT disc. The hydrogen peroxide disinfects by killing bacteria, fungi, and viruses found on the contact lenses. Because the concentration of hydrogen peroxide needed to disinfect is irritating to eyes, the hydrogen peroxide needs to be neutralized, or decomposed, before the contact lenses can be used again. A general chemistry experiment is described where the kinetics of the catalyzed decomposition of the hydrogen peroxide are studied by measuring the amount of oxygen generated as a function of time. The order of the reaction with respect to the hydrogen peroxide, the rate constant, and the energy of activation are determined. The integrated rate law is used to determine the time required to decompose the hydrogen peroxide to a concentration that is safe for eyes.

  12. 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.

  13. 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

  14. Uranyl peroxide enhanced nuclear fuel corrosion in seawater.

    Science.gov (United States)

    Armstrong, Christopher R; Nyman, May; Shvareva, Tatiana; Sigmon, Ginger E; Burns, Peter C; Navrotsky, Alexandra

    2012-02-07

    The Fukushima-Daiichi nuclear accident brought together compromised irradiated fuel and large amounts of seawater in a high radiation field. Based on newly acquired thermochemical data for a series of uranyl peroxide compounds containing charge-balancing alkali cations, here we show that nanoscale cage clusters containing as many as 60 uranyl ions, bonded through peroxide and hydroxide bridges, are likely to form in solution or as precipitates under such conditions. These species will enhance the corrosion of the damaged fuel and, being thermodynamically stable and kinetically persistent in the absence of peroxide, they can potentially transport uranium over long distances.

  15. Electron irradiation effects on lithium peroxide

    Science.gov (United States)

    Kikkawa, Jun; Shiotsuki, Taishi; Shimo, Yusuke; Koshiya, Shogo; Nagai, Takuro; Nito, Takehiro; Kimoto, Koji

    2018-03-01

    In this study, electron irradiation effects on lithium peroxide (Li2O2), which is an important discharge product of Li-air (or Li-O2) batteries, were investigated using selected-area electron diffraction (SAED) and high-energy resolution electron energy-loss spectroscopy (EELS). The results obtained show that Li2O2 to Li2O transformation occurs with 80 and 300 keV incident electrons under high electron dose rates at 20 and -183 °C. The Li2O2 to Li2O transformation rate for 300 keV was 1/5 of that for 80 keV with the irradiation taking place at -183 °C. We also present a series of the EELS spectra that can be used as a criterion to judge the molar ratio of Li2O to Li2O2 in the general systems where Li2O2 and Li2O coexist.

  16. Analysis of lipid peroxidation kinetics. I

    DEFF Research Database (Denmark)

    Doktorov, Alexander B.; Lukzen, Nikita N.; Pedersen, Jørgen Boiden

    2008-01-01

    concentrations of reactants or different ways of initiating the re-  action. Nor has it been possible to predict the time dependence of the  products. The reason for these problems is the complicated structure  of the kinetic scheme, which includes a chain reaction. In this work  we perform an in depth analysis......  The kinetics of the lipid peroxidation reaction is only partly under-  stood. Although the set of reactions constituting the overall reaction  is believed to be known, it has not been possible to predict how the  reaction will respond to a change of one or more of the parameters, e.g.  initial...... of the importance of the individual  reaction steps and we introduce a new quasi-stationary concentration  method based on the assumption that one or more concentrations vary  much slower than the others. We show that it is justified to use a  quasi-stationary concentration approximation for the alkyl radical L...

  17. Plutonium peroxide precipitation: review and current research

    International Nuclear Information System (INIS)

    Hagan, P.G.; Miner, F.J.

    1980-01-01

    Increasing the HNO 3 concentration decreases the filtration time but increases the plutonium concentration in the filtrate. A compromise was therefore necessary. If a minimum plutonium concentration is required in the filtrate, the acidity could be lowered to 1.9M with an approximate doubling in the filtration time. The H 2 O 2 concentration has little effect on filtration time. However, the higher the H 2 O 2 concentration, the less plutonium lost to the filtrate. Concentrations higher than the 22 moles/mole Pu recommended (at least up to 30 molar which was the highest investigated) would be beneficial if reagent costs are not excessive and production capacity exists for destroying the excess H 2 O 2 in the filtrate. Although the effect is not large, filtration time is shorter and the plutonium concentration in the filtrate is lower if metallic impurities are present. The slowest rate of H 2 O 2 addition investigated gives a plutonium peroxide precipitate with the fastest filtration time. The rate of addition has very little effect on the plutonium concentration in the filtrate. The temperature has little effect on the filtration time. 14 0 C is recommended since decomposition of H 2 O 2 would be slower at 14 0 C than at 22 0 C (min. Pu content in the filtrate). The effect of digestion time on both the filtration time and the plutonium content in the filtrate is minor, so the shortest digestion time investigated is recommended

  18. 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.)

  19. 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)

  20. 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.

  1. 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.

  2. Quantifying intracellular hydrogen peroxide perturbations in terms of concentration

    Directory of Open Access Journals (Sweden)

    Beijing K. Huang

    2014-01-01

    Full Text Available Molecular level, mechanistic understanding of the roles of reactive oxygen species (ROS in a variety of pathological conditions is hindered by the difficulties associated with determining the concentration of various ROS species. Here, we present an approach that converts fold-change in the signal from an intracellular sensor of hydrogen peroxide into changes in absolute concentration. The method uses extracellular additions of peroxide and an improved biochemical measurement of the gradient between extracellular and intracellular peroxide concentrations to calibrate the intracellular sensor. By measuring peroxiredoxin activity, we found that this gradient is 650-fold rather than the 7–10-fold that is widely cited. The resulting calibration is important for understanding the mass-action kinetics of complex networks of redox reactions, and it enables meaningful characterization and comparison of outputs from endogenous peroxide generating tools and therapeutics across studies.

  3. Vaporized Hydrogen Peroxide (VHP) Decontamination of VX, GD, and HD

    National Research Council Canada - National Science Library

    Wagner, George W; Sorrick, David C; Procell, Lawrence R; Hess, Zoe A; Brickhouse, Mark D; McVey, Iain F; Schwartz, Lewis I

    2003-01-01

    Vaporized Hydrogen Peroxide (VHP) has been utilized for more than a decade to sterilize clean rooms and pharmaceutical processing equipment and, quite recently, to decontaminate anthrax-ridden buildings...

  4. Gold-catalyzed oxidation of substituted phenols by hydrogen peroxide

    KAUST Repository

    Cheneviere, Yohan; Caps, Valerie; Tuel, Alain

    2010-01-01

    Gold nanoparticles deposited on inorganic supports are efficient catalysts for the oxidation of various substituted phenols (2,6-di-tert-butyl phenol and 2,3,6-trimethyl phenol) with aqueous hydrogen peroxide. By contrast to more conventional

  5. Free standing graphene oxide film for hydrogen peroxide sensing

    Science.gov (United States)

    Ranjan, Pranay; Balakrishnan, Jayakumar; Thakur, Ajay D.

    2018-05-01

    We report hydrogen peroxide (H2O2)sensing using free standing graphene oxide thin films prepared using a cost effective scalable approach. Such sensors may find application in pharmaceutical and food processing industries.

  6. the effects of vitamin e supplementation on serum lipid peroxidation ...

    African Journals Online (AJOL)

    DR. C.O.NWAIGWE

    The effects of dietary supplementation of vitamin E on feed intake and serum lipid peroxidation formation were ... belongs to the family Birnaviridae and of the genus Birnavirus ... diseases, Alzheimer's disease and increased resistance to ...

  7. Lab-scale hydrogen peroxide data from ECBC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from small lab scale tests conducted at ECBC. It contains efficacy data as well as data on env conditions such as temperature, RH, and hydrogen peroxide vapor...

  8. Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide

    National Research Council Canada - National Science Library

    Bessette, Russell R

    2005-01-01

    An electrochemical potentiometric titration method that entails titration of a known volume of a catholyte containing an unknown amount of hydrogen peroxide in a titration cell having two electrodes...

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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....

  14. 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.

  15. Efficacy of Mouthwashes Containing Hydrogen Peroxide on Tooth Whitening

    OpenAIRE

    Karadas, Muhammet; Hatipoglu, Omer

    2015-01-01

    The aim of this study was to analyze the efficacy of mouthwashes containing hydrogen peroxide compared with 10% carbamide peroxide (CP) gel. Fifty enamel-dentin samples were obtained from bovine incisors and then stained in a tea solution. The stained samples were randomly divided into five groups according to the whitening product applied (n = 10): AS: no whitening (negative control), with the samples stored in artificial saliva; CR: Crest 3D White mouthwash; LS: Listerine Whitening mouthwas...

  16. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    Science.gov (United States)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  17. Physico Chemical Characteristic of Kappa Carrageenan Degraded Using Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Rizky Febriansyah Siregar

    2017-02-01

    Full Text Available AbstractKappa carrageenan is polysaccharide that widely used in food, pharmaceutical, cosmetic, textile and printing industries as coagulate agent, stabilizer and gelling agent. Hydrogen peroxide (H2O2 is strong oxidator to degrade polysaccharide. Hydrogen peroxide has some advantades such as cheap, easy to get and savety environment. Degradation method using hydrogen peroxide is a technology based on establishment radical hydoxile reactive that attack the glycosidic of polysaccharides as a result reducing in molecular weight of polysaccharide. The aims of this study were to analyze the effect of hydrogen peroxide concentration, temperature and degradation time to molecular weight of refined kappa carrageenan. Structural changes on kappa carrageenan degradation were characterized by viscometer, SEM and FTIR. Hydrogen peroxide concentration, temperature and degradation time were significantly reducing molecular weight and changes in the structural function of refined kappa carrageenan. The lowest molecular weight of refined kappa carrageenan degraded was obtained from the treatment 3% of hydrogen peroxide at temperature 80°C and degradation time for 4 hours.

  18. 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.

  19. 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.)

  20. 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 ...

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Mechanical properties of self-curing concrete (SCUC

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-12-01

    Full Text Available The mechanical properties of concrete containing self-curing agents are investigated in this paper. In this study, two materials were selected as self-curing agents with different amounts, and the addition of silica fume was studied. The self-curing agents were, pre-soaked lightweight aggregate (Leca; 0.0%, 10%, 15%, and 20% of volume of sand; or polyethylene-glycol (Ch.; 1%, 2%, and 3% by weight of cement. To carry out this study the cement content of 300, 400, 500 kg/m3, water/cement ratio of 0.5, 0.4, 0.3 and 0.0%, 15% silica fume of weight of cement as an additive were used in concrete mixes. The mechanical properties were evaluated while the concrete specimens were subjected to air curing regime (in the laboratory environment with 25 °C, 65% R.H. during the experiment. The results show that, the use of self-curing agents in concrete effectively improved the mechanical properties. The concrete used polyethylene-glycol as self-curing agent, attained higher values of mechanical properties than concrete with saturated Leca. In all cases, either 2% Ch. or 15% Leca was the optimum ratio compared with the other ratios. Higher cement content and/or lower water/cement ratio lead(s to more efficient performance of self-curing agents in concrete. Incorporation of silica fume into self-curing concrete mixture enhanced all mechanical properties, not only due to its pozzolanic reaction, but also due to its ability to retain water inside concrete.

  7. Curing kinetics of alkyd/melamine resin mixtures

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana C.

    2009-01-01

    Full Text Available Alkyd resins are the most popular and useful synthetic resins applied as the binder in protective coatings. Frequently they are not used alone but are modified with other synthetic resins in the manufacture of the coatings. An alkyd/melamine resin mixture is the usual composition for the preparation of coating called 'baking enamel' and it is cured through functional groups of resins at high temperatures. In this paper, curing kinetics of alkyd resins based on castor oil and dehydrated castor oil with melamine resin, has been studied by DSC method with programmed heating and in isothermal mode. The results determined from dynamic DSC curves were mathematically transformed using the Ozawa isoconversional method for obtaining the isothermal data. These results, degree of curing versus time, are in good agreement with those determined by the isothermal DSC experiments. By applying the Ozawa method it is possible to calculate the isothermal kinetic parameters for the alkyd/melamine resin mixtures curing using only calorimetric data obtained by dynamic DSC runs. Depending on the alkyd resin type and ratio in mixtures the values of activation energies of curing process of resin mixtures are from 51.3 to 114 kJ mol-1. The rate constant of curing increases with increasing the content of melamine resin in the mixture and with curing temperature. The reaction order varies from 1.12 to 1.37 for alkyd based on dehydrated castor oil/melamine resin mixtures and from 1.74 to 2.03 for mixtures with alkyd based on castor oil. Based on the results obtained, we propose that dehydrated castor oil alkyd/melamine resin mixtures can be used in practice (curing temperatures from 120 to 160°C.

  8. Beliefs about the causes and cures of depression

    OpenAIRE

    Furnham, A.; Ritchie, W.; Lay, A.

    2016-01-01

    BACKGROUND: This study used attitude statement and vignette methodology to examine a mixed British sample’s belies about the causes and consequences of depression. AIMS: To test whether the group would recognise both vignettes with having depression and that the favoured cure would be Psychotherapy/Talking Cure. METHOD: In all, 320 adults completed a two-part questionnaire. In the first part, they were given two vignettes describing a 30-year-old female and a 45-year-old male...

  9. Manufacturing prepainted steel sheet by electron beam curing

    International Nuclear Information System (INIS)

    Oka, Joji

    1987-01-01

    Several advantages are offered by electron beam curing. A formidably hard and stain resistant paint film which is difficult to obtain by heat curing paint is developed. As a result, a unique new prepainted steel is produced. Four technologies are involved: development high-quality paint, selection of optimum electron beam processor, technology to control electron beam processing atmosphere and secondary X-ray shield technology. These technologies are described in detail. (A.J.)

  10. Spectroscopic studies of europium-tetracyclines complexes and their applications in detection of hydrogen peroxide and urea peroxide

    International Nuclear Information System (INIS)

    Grasso, Andrea Nastri

    2010-01-01

    In this work were studied the spectroscopic properties of trivalent europium ion complexed with components of tetracycline family, chlorotetracycline, oxytetracycline and metacycline, in the presence of hydrogen peroxide and urea peroxide. Optical parameters were obtained such as absorption, emission, lifetime and calibration curves were constructed for luminescence spectra. Experiments were carried out with both inorganic compounds and europium-tetracyclines complexes in order to verify possible interferences. Studies for glucose determination were also described using europium-tetracyclines complexes as biosensors. Results show that europium tetracyclines complexes emit a narrow band in the visible region and, in the presence of hydrogen peroxide or urea peroxide there is a greater enhancement in their luminescence and lifetime. Thus, europium-tetracyclines complexes studied can be used as biosensors for hydrogen and urea peroxides determination as a low cost and room temperature method. An indirect method for glucose determination was studied by adding glucose oxidase enzyme in europium-tetracyclines complex in the presence of glucose promoting as product hydrogen peroxide. (author)

  11. Monitoring the Cure State of Thermosetting Resins by Ultrasound.

    Science.gov (United States)

    Lionetto, Francesca; Maffezzoli, Alfonso

    2013-09-05

    The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA) for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to the resin storage modulus and density, while the attenuation is related to the energy dissipation and scattering in the curing resin. The paper reviews the results obtained by the authors' research group in the last decade by means of in-house made ultrasonic set-ups for both contact and air-coupled ultrasonic experiments. The basics of the ultrasonic wave propagation in polymers and examples of measurements of the time-evolution of ultrasonic longitudinal modulus and chemical conversion of different thermosetting resins are presented. The effect of temperature on the cure kinetics, the comparison with rheological, low frequency dynamic mechanical and calorimetric results, and the correlation between ultrasonic modulus and crosslinking density will be also discussed. The paper highlights the reliability of ultrasonic wave propagation for monitoring the physical changes taking place during curing and the potential for online monitoring during polymer and polymer matrix composite processing.

  12. Monitoring the Cure State of Thermosetting Resins by Ultrasound

    Directory of Open Access Journals (Sweden)

    Alfonso Maffezzoli

    2013-09-01

    Full Text Available The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to the resin storage modulus and density, while the attenuation is related to the energy dissipation and scattering in the curing resin. The paper reviews the results obtained by the authors’ research group in the last decade by means of in-house made ultrasonic set-ups for both contact and air-coupled ultrasonic experiments. The basics of the ultrasonic wave propagation in polymers and examples of measurements of the time-evolution of ultrasonic longitudinal modulus and chemical conversion of different thermosetting resins are presented. The effect of temperature on the cure kinetics, the comparison with rheological, low frequency dynamic mechanical and calorimetric results, and the correlation between ultrasonic modulus and crosslinking density will be also discussed. The paper highlights the reliability of ultrasonic wave propagation for monitoring the physical changes taking place during curing and the potential for online monitoring during polymer and polymer matrix composite processing.

  13. Depth of cure of bulk-fill flowable composite resins.

    Science.gov (United States)

    Pedalino, Inaam; Hartup, Grant R; Vandewalle, Kraig S

    2015-01-01

    In recent years, manufacturers have introduced flowable composite resins that reportedly can be placed in increments of 4 mm or greater. The purpose of this study was to evaluate the depth of cure of bulk-fill flowable composite resins (SureFil SDR Flow, Grandio Flow, and Venus Bulk Fill) and a conventional flowable composite resin (Revolution Formula 2). Depth of cure was measured in terms of bottom-maximum Knoop hardness number (KHN) ratios and the International Organization for Standardization (ISO) 4049 scrape technique. Shades A2 and A3 of SureFil SDR Flow, Grandio Flow, and Revolution Formula 2 were tested. Venus Bulk Fill was tested in its only available shade (universal). Specimens in thicknesses of 2, 3, 4, 5, and 6 mm were polymerized for 20 or 40 seconds, and a hardness tester was used to determine the hardness ratios for each shade at each thickness. For the scraping technique, after specimens were exposed to the curing light, unpolymerized composite resin was removed with a plastic instrument, the polymerized composite was measured, and the length was divided by 2 per ISO guidelines. According to the KHN ratios and the scrape test, Venus Bulk Fill predictably exceeded the manufacturer's claim of a 4-mm depth of cure at both 20 and 40 seconds of curing time. The overall results for depth of cure showed that Venus Bulk Fill ≥ SureFil SDR Flow ≥ Grandio Flow ≥ Revolution Formula 2.

  14. Fight fire with fire: Gene therapy strategies to cure HIV.

    Science.gov (United States)

    Huyghe, Jon; Magdalena, Sips; Vandekerckhove, Linos

    2017-08-01

    Human Immunodeficiency Virus (HIV) to date remains one of the most notorious viruses mankind has ever faced. Despite enormous investments in HIV research for more than 30 years an effective cure for HIV has been elusive. Areas covered: Combination antiretroviral therapy (cART) suppresses active viral replication, but is not able to eliminate the virus completely due to stable integration of HIV inside the host genome of infected cells and the establishment of a latent reservoir, that is insensitive to cART. Nevertheless, this latent HIV reservoir is fully capable to refuel viral replication when treatment is stopped, creating a major obstacle towards a cure for HIV. Several gene therapy approaches ranging from the generation of HIV resistant CD4 + T cells to the eradication of HIV infected cells by immune cell engineering are currently under pre-clinical and clinical investigation and may present a promising road to a cure. In this review, we focus on the status and the prospects of gene therapy strategies to cure/eradicate HIV. Expert commentary: Recent advances in gene therapy for oncology and infectious diseases indicate that gene therapy may be a feasible and very potent cure strategy, and therefore a potential game changer in the search for an effective HIV cure.

  15. The Amoebicidal Effect of Ergosterol Peroxide Isolated from Pleurotus ostreatus.

    Science.gov (United States)

    Meza-Menchaca, Thuluz; Suárez-Medellín, Jorge; Del Ángel-Piña, Christian; Trigos, Ángel

    2015-12-01

    Dysentery is an inflammation of the intestine caused by the protozoan parasite Entamoeba histolytica and is a recurrent health problem affecting millions of people worldwide. Because of the magnitude of this disease, finding novel strategies for treatment that does not affect human cells is necessary. Ergosterol peroxide is a sterol particularly known as a major cytotoxic agent with a wide spectrum of biological activities produced by edible and medicinal mushrooms. The aim of this report is to evaluate the amoebicidal activity of ergosterol peroxide (5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol isolated from 5α, 8α-epidioxy-22E-ergosta-6,22-dien-3β-ol) (Jacq.) P. Kumm. f. sp. Florida. Our results show that ergosterol peroxide produced a strong cytotoxic effect against amoebic growth. The inhibitory concentration IC50 of ergosterol peroxide was evaluated. The interaction between E. histolytica and ergosterol peroxide in vitro resulted in strong amoebicidal activity (IC50  = 4.23 nM) that may be due to the oxidatory effect on the parasitic membrane. We also tested selective toxicity of ergosterol peroxide using a cell line CCL-241, a human epithelial cell line isolated from normal human fetal intestinal tissue. To the best of our knowledge, this is the first report on the cytotoxicity of ergosterol peroxide against E. histolytica, which uncovers a new biological property of the lipidic compound isolated from Pleurotus ostreatus (Jacq.) P. Kumm. f. sp. Florida. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Different modes of hydrogen peroxide action during seed germination

    Directory of Open Access Journals (Sweden)

    Łukasz eWojtyla

    2016-02-01

    Full Text Available Hydrogen peroxide was initially recognized as a toxic molecule that causes damage at different levels of cell organization and thus losses in cell viability. From the 1990s, the role of hydrogen peroxide as a signaling molecule in plants has also been discussed. The beneficial role of H2O2 as a central hub integrating signaling network in response to biotic and abiotic stress and during developmental processes is now well established. Seed germination is the most pivotal phase of the plant life cycle, affecting plant growth and productivity. The function of hydrogen peroxide in seed germination and seed aging has been illustrated in numerous studies; however, the exact role of this molecule remains unknown. This review evaluates evidence that shows that H2O2 functions as a signaling molecule in seed physiology in accordance with the known biology and biochemistry of H2O2. The importance of crosstalk between hydrogen peroxide and a number of signaling molecules, including plant phytohormones such as abscisic acid, gibberellins and ethylene and reactive molecules such as nitric oxide and hydrogen sulfide acting on cell communication and signaling during seed germination, is highlighted. The current study also focuses on the detrimental effects of H2O2 on seed biology, i.e., seed aging that leads to a loss of germination efficiency. The dual nature of hydrogen peroxide as a toxic molecule on one hand and as a signal molecule on the other is made possible through the precise spatial and temporal control of its production and degradation. Levels of hydrogen peroxide in germinating seeds and young seedlings can be modulated via pre-sowing seed priming/conditioning. This rather simple method is shown to be a valuable tool for improving seed quality and for enhancing seed stress tolerance during post-priming germination. In this review, we outline how seed priming/conditioning affects the integrative role of hydrogen peroxide in seed germination and

  17. Lipid Peroxidation: Pathophysiology and Pharmacological Implications in the Eye

    Directory of Open Access Journals (Sweden)

    Ya Fatou eNjie-Mbye

    2013-12-01

    Full Text Available Oxygen-derived free radicals such as hydroxyl and hydroperoxyl species have been shown to oxidize phospholipids and other membrane lipid components leading to lipid peroxidation. In the eye, lipid peroxidation has been reported to play an important role in degenerative ocular diseases (age-related macular degeneration, cataract, glaucoma, diabetic retinopathy. Indeed, ocular tissues are prone to damage from reactive oxygen species due to stress from constant exposure of the eye to sunlight, atmospheric oxygen and environmental chemicals. Furthermore, free radical catalyzed peroxidation of long chain polyunsaturated acids (LCPUFAs such as arachidonic acid and docosahexaenoic acid leads to generation of LCPUFA metabolites including isoprostanes and neuroprostanes that may further exert pharmacological/toxicological actions in ocular tissues. Evidence from literature supports the presence of endogenous defense mechanisms against reactive oxygen species in the eye, thereby presenting new avenues for the prevention and treatment of ocular degeneration. Hydrogen peroxide (H2O2 and synthetic peroxides can exert pharmacological and toxicological effects on tissues of the anterior uvea of several mammalian species. There is evidence suggesting that the retina, especially retinal ganglion cells can exhibit unique characteristics of antioxidant defense mechanisms. In the posterior segment of the eye, H2O2 and synthetic peroxides produce an inhibitory action on glutamate release (using [3H]-D-aspartate as a marker, in vitro and on the endogenous glutamate and glycine concentrations in vivo. In addition to peroxides, isoprostanes can elicit both excitatory and inhibitory effects on norepinephrine (NE release from sympathetic nerves in isolated mammalian iris ciliary bodies. Whereas isoprostanes attenuate dopamine release from mammalian neural retina, in vitro, these novel arachidonic acid metabolites exhibit a biphasic regulatory effect on glutamate release

  18. Influence of curing time, overlay material and thickness on three light-curing composites used for luting indirect composite restorations.

    Science.gov (United States)

    D'Arcangelo, Camillo; De Angelis, Francesco; Vadini, Mirco; Carluccio, Fabio; Vitalone, Laura Merla; D'Amario, Maurizio

    2012-08-01

    To assess the microhardness of three resin composites employed in the adhesive luting of indirect composite restorations and examine the influence of the overlay material and thickness as well as the curing time on polymerization rate. Three commercially available resin composites were selected: Enamel Plus HRI (Micerium) (ENA), Saremco ELS (Saremco Dental) (SAR), Esthet-X HD (Dentsply/DeTrey) (EST-X). Post-polymerized cylinders of 6 different thicknesses were produced and used as overlays: 2 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, and 6 mm. Two-mm-thick disks were produced and employed as underlays. A standardized amount of composite paste was placed between the underlay and the overlay surfaces which were maintained at a fixed distance of 0.5 mm. Light curing of the luting composite layer was performed through the overlays for 40, 80, or 120 s. For each specimen, the composite to be cured, the cured overlay, and the underlay were made out of the same batch of resin composite. All specimens were assigned to three experimental groups on the basis of the resin composite used, and to subgroups on the basis of the overlay thickness and the curing time, resulting in 54 experimental subgroups (n = 5). Forty-five additional specimens, 15 for each material under investigation, were produced and subjected to 40, 80, or 120 s of light curing using a microscope glass as an overlay; they were assigned to 9 control subgroups (n = 5). Three Vicker's hardness (VH) indentations were performed on each specimen. Means and standard deviations were calculated. Data were statistically analyzed using 3-way ANOVA. Within the same material, VH values lower than 55% of control were not considered acceptable. The used material, the overlay thickness, and the curing time significantly influenced VH values. In the ENA group, acceptable hardness values were achieved with 3.5-mm or thinner overlays after 120 or 80 s curing time (VH 41.75 and 39.32, respectively), and with 2-mm overlays after 40 s (VH 54

  19. Effect of various infection-control methods for light-cure units on the cure of composite resins.

    Science.gov (United States)

    Chong, S L; Lam, Y K; Lee, F K; Ramalingam, L; Yeo, A C; Lim, C C

    1998-01-01

    This study (1) compared the curing-light intensity with various barrier infection-control methods used to prevent cross contamination, (2) compared the Knoop hardness value of cured composite resin when various barrier control methods were used, and (3) correlated the hardness of the composite resin with the light-intensity output when different infection-control methods were used. The light-cure unit tips were covered with barriers, such as cellophane wrap, plastic gloves, Steri-shields, and finger cots. The control group had no barrier. Composite resins were then cured for each of the five groups, and their Knoop hardness values recorded. The results showed that there was significant statistical difference in the light-intensity output among the five groups. However, there was no significant statistical difference in the Knoop hardness values among any of the groups. There was also no correlation between the Knoop hardness value of the composite resin with the light-intensity output and the different infection-control methods. Therefore, any of the five infection-control methods could be used as barriers for preventing cross-contamination of the light-cure unit tip, for the light-intensity output for all five groups exceeded the recommended value of 300 W/m2. However, to allow a greater margin of error in clinical situations, the authors recommend that the plastic glove or the cellophane wrap be used to wrap the light-cure tip, since these barriers allowed the highest light-intensity output.

  20. Singlet oxygen-mediated formation of protein peroxides within cells

    International Nuclear Information System (INIS)

    Wright, A.; Policarpio, V.

    2003-01-01

    Full text: Singlet oxygen is generated by a number of cellular, enzymatic and chemical reactions as well as by exposure to UV, or visible light in the presence of a sensitizer; as a consequence this oxidant has been proposed as a damaging agent in a number of pathologies including photo-aging and skin cancer. Proteins are major targets for singlet oxygen as a result of their abundance and high rate constants for reaction. In this study it is shown that illumination of viable, sensitizer-loaded, THP-1 (human monocyte-like) cells with visible light gives rise to intra-cellular protein-derived peroxides. The peroxide yield increases with illumination time, requires the presence of the sensitizer, is enhanced in D 2 O, and decreased by azide; these data are consistent with the mediation of singlet oxygen. The concentration of peroxides detected, which is not affected by glucose or ascorbate loading of the cells, corresponds to ca. 1.5 nmoles peroxide per 10 6 cells using rose bengal as sensitizer, or 10 nmoles per mg cell protein and account for up to ca. 15% of the O 2 consumed by the cells. Similar peroxides have been detected on isolated cellular proteins exposed to light in the presence of rose bengal and oxygen. After cessation of illumination, the cellular protein peroxide levels decreases with t 1/2 ca. 4 hrs at 37 deg C, and this is associated with increased cell lysis. Decomposition of protein peroxides formed within cells, or on isolated cellular proteins, by metal ions, gives rise to radicals as detected by EPR spin trapping. These protein peroxides, and radicals derived from them, can inactivate key cellular enzymes (including caspases, GAPDH and glutathione reductase) and induce DNA base oxidation, strand breaks and DNA-protein cross-links. These studies demonstrate that exposure of intact cells to visible light in the presence of a sensitizer gives rise to novel long-lived, but reactive, intra-cellular protein peroxides via singlet oxygen

  1. UV-cured methacrylic-silica hybrids: Effect of oxygen inhibition on photo-curing kinetics

    International Nuclear Information System (INIS)

    Corcione, C. Esposito; Striani, R.; Frigione, M.

    2014-01-01

    Highlights: • The kinetic behavior of novel photopolymerizable organic–inorganic hybrid system was studied as a function of the composition and of the atmosphere for reactions. • The UV-curing reaction of the hybrid mixture was found fast and complete. • The combined presence of thiol monomer and nanostructured silica allows to reduce the effect of inhibition of oxygen towards the radical photopolymerization. - Abstract: The kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formulations, previously developed, was studied and compared to that of a reference control system. The organic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a high siloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silica nano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensation reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, in presence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analyses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effect of oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxane based monomers was found to be strongly reduced in the hybrid system, especially when a proper thiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radical photopolymerization reactions, obtaining a good agreement between the experimental data and the theoretical model. From the comparison of the kinetic constants calculated for control and hybrid systems, it was possible to assess the effect of the composition, as well as of the atmosphere used during the photo-polymerization process, on the kinetic of photopolymerization reaction

  2. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)

    2008-01-07

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  3. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    International Nuclear Information System (INIS)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H 2 O 2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo

  4. Safety issues of tooth whitening using peroxide-based materials.

    Science.gov (United States)

    Li, Y; Greenwall, L

    2013-07-01

    In-office tooth whitening using hydrogen peroxide (H₂O₂) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H₂O₂, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

  5. Destruction of oxalate by reaction with hydrogen peroxide. [Hydrazine oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Mailen, J.C.; Tallent, O.K.; Arwood, P.C.

    1981-09-01

    The destruction of oxalate by oxidation to carbon dioxide using hydrogen peroxide was studied as an alternative method for the disposal of oxalate in connection with the possible use of an aqueous hydrazine oxalate solution as a scrubbing agent for solvent cleanup in processes for the recovery of uranium, plutonium, and thorium by solvent extraction. The rate of oxidation of oxalate by hydrogen peroxide in acid solution at the reflux temperature was adequate for process application; reaction half-times at 100/sup 0/C were less than one hour when the hydrogen peroxide concentration was greater than 0.5 M. The reaction was first order with respect to both the oxalate and hydrogen peroxide concentrations and had an activation energy of 58.7 kJ/g-mol. The rate increased with the hydrogen ion concentration as (H/sup +/)/sup 0/ /sup 3/ but was not significantly affected by the presence of 100 ppM of uranium or copper in solution. In the near-neutral hydrazine oxalate solutions, the reaction of either component with hydrogen peroxide was too slow for process application.

  6. Aluminum induces lipid peroxidation and aggregation of human blood platelets

    Directory of Open Access Journals (Sweden)

    T.J.C. Neiva

    1997-05-01

    Full Text Available Aluminum (Al3+ intoxication is thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations arising from long-term hemodialysis. Although the metal does not present redox capacity, it can stimulate tissue lipid peroxidation in animal models. Furthermore, in vitro studies have revealed that the fluoroaluminate complex induces diacylglycerol formation, 43-kDa protein phosphorylation and aggregation. Based on these observations, we postulated that Al3+-induced blood platelet aggregation was mediated by lipid peroxidation. Using chemiluminescence (CL of luminol as an index of total lipid peroxidation capacity, we established a correlation between lipid peroxidation capacity and platelet aggregation. Al3+ (20-100 µM stimulated CL production by human blood platelets as well as their aggregation. Incubation of the platelets with the antioxidants nor-dihydroguaiaretic acid (NDGA (100 µM and n-propyl gallate (NPG (100 µM, inhibitors of the lipoxygenase pathway, completely prevented CL and platelet aggregation. Acetyl salicylic acid (ASA (100 µM, an inhibitor of the cyclooxygenase pathway, was a weaker inhibitor of both events. These findings suggest that Al3+ stimulates lipid peroxidation and the lipoxygenase pathway in human blood platelets thereby causing their aggregation

  7. Lipid peroxidation and antioxidant enzymes in male infertility.

    Directory of Open Access Journals (Sweden)

    Dandekar S

    2002-07-01

    Full Text Available BACKGROUND AND AIM: Mammalian spermatozoa are rich in polyunsaturated fatty acids and are very susceptible to attack by reactive oxygen species (ROS and membrane lipid peroxide ion. Normally a balance is maintained between the amount of ROS produced and that scavenged. Cellular damage arises when this equilibrium is disturbed. A shift in the levels of ROS towards pro-oxidants in semen and vaginal secretions can induce an oxidative stress on spermatozoa. The aim was to study lipid peroxidation and antioxidant enzymes such as catalase, glutathione peroxidase and superoxide dismutase (SOD and to correlate the same, with the ′water test′, in male infertility. SETTINGS: Experimental study. SUBJECTS AND METHODS: Ejaculates from a total of 83 infertile and fertile healthy individuals were obtained. Lipid peroxidation and antioxidant enzyme levels were studied and correlated with water test. RESULTS: The results indicate that (i the antioxidant enzyme catalase showed no significant changes in the various pathological samples, (ii antioxidant enzymes SOD and glutathione peroxidase correlate positively with asthenozoospermic samples and (iii the degree of lipid peroxidation also correlates positively with the poorly swollen sperm tails. The increase in SOD and glutathione peroxidase values, in the pathological cases represents an attempt made to overcome the reactive oxygen species. CONCLUSION: Water test could be used as a preliminary marker test for sperm tail damage by reactive oxygen species, since it correlates very well with lipid peroxidation and antioxidant enzymes.

  8. A chemiluminescent method for determination of lipid peroxidation

    International Nuclear Information System (INIS)

    Liang Xiaofeng; Hu Tianxi; Fan Xiaobing

    2003-01-01

    We established a chemiluminescent system for determination of lipid peroxidation and screening anti-oxidants. The lipid containing unsaturated fatly acids was injected into a galls tube. Luminol solution and the deionized water were added into it too. The glass tube was put into a preincubation box to incubate it for 0.5 h at 37 degree C. AAPH solution was injected into the tube for immediate measurement in a biochemiluminometer at 38-39 degree C. The pulses /6s(CP6s) were determined with T-2 program. Chemiluminescent dynamic and lipid peroxidation changes were observed continuously. Once the CL intensity of lipid peroxidation got peak, the antioxidant which has different concentration was added immediately in situ. A certain CL intensity (CP6s) was chosen as evaluation index to compare the activity of antioxidants. A luminol chemiluminescent system for determination of lipid peroxidation has been made. It was found that Vit. C, teapolyphenol, and glutathione have effects on scavenging lipid free radicals. The new method is quick, sensitive, and simple for determination of lipid peroxidation and screening antioxidants

  9. 7 CFR 30.36 - Class 1; flue-cured types and groups.

    Science.gov (United States)

    2010-01-01

    ...-cured, produced principally in the Piedmont sections of Virginia and North Carolina. (b) Type 11b. That... lying between the Piedmont and coastal plains regions of Virginia and North Carolina. (c) Type 12. That type of flue-cured tobacco commonly known as Eastern Flue-cured or Eastern Carolina Flue-cured...

  10. Reproducing Phenomenology of Peroxidation Kinetics via Model Optimization

    Science.gov (United States)

    Ruslanov, Anatole D.; Bashylau, Anton V.

    2010-06-01

    We studied mathematical modeling of lipid peroxidation using a biochemical model system of iron (II)-ascorbate-dependent lipid peroxidation of rat hepatocyte mitochondrial fractions. We found that antioxidants extracted from plants demonstrate a high intensity of peroxidation inhibition. We simplified the system of differential equations that describes the kinetics of the mathematical model to a first order equation, which can be solved analytically. Moreover, we endeavor to algorithmically and heuristically recreate the processes and construct an environment that closely resembles the corresponding natural system. Our results demonstrate that it is possible to theoretically predict both the kinetics of oxidation and the intensity of inhibition without resorting to analytical and biochemical research, which is important for cost-effective discovery and development of medical agents with antioxidant action from the medicinal plants.

  11. Synthesis of unstable cyclic peroxides for chemiluminescence studies

    Energy Technology Data Exchange (ETDEWEB)

    Bartoloni, Fernando H.; Oliveira, Marcelo A. de; Augusto, Felipe A.; Ciscato, Luiz Francisco M.L.; Bastos, Erick L.; Baader, Wilhelm J., E-mail: wjbaader@iq.usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2012-11-15

    Cyclic four-membered ring peroxides are important high-energy intermediates in a variety of chemi and bioluminescence transformations. Specifically, a-peroxy lactones (1,2-dioxetanones) have been considered as model systems for efficient firefly bioluminescence. However, the preparation of such highly unstable compounds is extremely difficult and, therefore, only few research groups have been able to study the properties of these substances. In this study, the synthesis, purification and characterization of three 1,2-dioxetanones are reported and a detailed procedure for the known synthesis of diphenoyl peroxide, another important model compound for the chemical generation of electronically excited states, is provided. For most of these peroxides, the complete spectroscopic characterization is reported here for the first time. (author)

  12. Electrochemical behaviour of platinum in hydrogen peroxide solution (1963)

    International Nuclear Information System (INIS)

    Prost, G.H.

    1963-06-01

    The relative stability of hydrogen peroxide in aqueous solution at 25 deg. C, allows its amperometric determination from the theory, using either its cathodic reduction or its anodic oxidation. The cathodic reduction yields a wave on a platinum electrode only when some oxygen is present in the solution. It cannot, therefore, be used for electrochemical determination. On the other hand, the anodic oxidation on platinum produces a wave which might be used. However, a passivation of platinum occurs at the same time. This passivation process is studied by means of potentio-kinetic, potentio-static, intensio-static curves and of pH measurements in the vicinity of the anode. A mechanism for passivation is presented, which takes into account the role of hydrogen peroxide as a reducing agent. This passivation rules out any analytical application of the oxidation reaction of hydrogen peroxide. (author) [fr

  13. Assessment of Salmonella survival in dry-cured Italian salami.

    Science.gov (United States)

    Bonardi, S; Bruini, I; Bolzoni, L; Cozzolino, P; Pierantoni, M; Brindani, F; Bellotti, P; Renzi, M; Pongolini, S

    2017-12-04

    The inactivation of Salmonella during curing of Italian traditional pork salami was investigated. A total of 150 batches of ground raw meat (GRM) used for salami manufacturing by four producers were tested for Salmonella by real-time PCR followed by ISO 6579 cultural confirmation and MPN enumeration. Salami produced with Salmonella positive GRMs were re-tested at the end of their curing period. Aw, pH and NaCl content were also measured. Detection of Salmonella was performed testing both 25 and 50g of the samples. By Real-Time PCR 37% of the GRMs resulted positive, but cultural detection of Salmonella was obtained in 14% of the samples only. Salmonella enumeration ranged from 31 MPN/g to Salmonella in 100% of all positive samples, vs. 62% of ISO-25g. Salami made of the contaminated GRMs were 29% Salmonella-positive, as most batches of salami produced with Salmonella-positive GRMs resulted negative after regular curing (20-48days). Overall, 13% of salami produced with Salmonella-contaminated GRMs were positive. They belonged to six batches, which turned out negative after prolonged curing ranging between 49 and 86days. Salmonella enumeration in salami ranged from 8.7 MPN/g to Salmonella in cured salami (p value: >0.05). The most common Salmonella serovars in GRMs were Derby (52%), Typhimurium monophasic variant 4, (Barbuti et al., 1993), 12:i:- (19%) and Stanley (10%). Salmonella Derby (56%), London, Branderup, Panama (13%, respectively) and Goldcoast (6%) were most frequent in cured salami. The study showed negative correlation between real-time CT values and cultural confirmation of Salmonella, as well as the importance of sample size for Salmonella detection. Among considered factors with possible effect on the occurrence of Salmonella in salami, statistical analysis revealed a role for aw in salami and for Salmonella load in GRMs, while pH and NaCl content did not significantly affect the probability of finding Salmonella in dry-cured salami in the context of

  14. Determination of hydrogen peroxide in water by chemiluminescence detection, (1). Flow injection type hydrogen peroxide detection system

    International Nuclear Information System (INIS)

    Yamashiro, Naoya; Uchida, Shunsuke; Satoh, Yoshiyuki; Morishima, Yusuke; Yokoyama, Hiroaki; Satoh, Tomonori; Sugama, Junichi; Yamada, Rie

    2004-01-01

    A flow injection type hydrogen peroxide detection system with a sub-ppb detection limit has been developed to determine hydrogen peroxide concentration in water sampled from a high temperature, high pressure hydrogen peroxide water loop. The hydrogen peroxide detector is based on luminol chemiluminescence spectroscopy. A small amount of sample water (20 μl) is mixed with a reagent mixture, an aqueous solution of luminol and Co 2+ catalyst, in a mixing cell which is installed just upstream from the detection cell. The optimum values for pH and the concentrations of luminol and Co 2+ ion have been determined to ensure a lower detectable limit and a higher reproducibility. The photocurrent detected by the detection system is expressed by a linear function of the hydrogen peroxide concentration in the region of lower concentration ([H 2 O 2 ] 2 O 2 ] in the region of higher concentration ([H 2 O 2 ] > 10 ppb). The luminous intensity of luminol chemiluminescence is the highest when pH of the reagent mixture is 11.0. Optimization of the major parameters gives the lowest detectable limit of 0.3 ppb. (author)

  15. Comparison of the heat generation of light curing units.

    Science.gov (United States)

    Bagis, Bora; Bagis, Yildirim; Ertas, Ertan; Ustaomer, Seda

    2008-02-01

    The aim of this study was to evaluate the heat generation of three different types of light curing units. Temperature increases were recorded from a distance of 1 mm from a thermocouple to the tip of three different types of light curing units including one quartz-tungsten halogen (QTH), one plasma arc (PAC), and one light emitting diode (LED) unit. An experimental model was designed to fix the 1 mm distance between the tip of the light curing units and the thermocouple wire. Temperature changes were recorded in 10 second intervals up to 40 seconds. (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light curing unit after a one hour standby period. Statistical analysis of the results was performed using the analysis of variance (ANOVA) and the Bonferroni Test. The highest temperature rises (54.4+/-1.65 degrees C) occurred during activation of a PAC light curing unit for every test period (pdamage to the pulp.

  16. Recent advance and applications in radiation curing of coatings

    International Nuclear Information System (INIS)

    Kishi, Naoyuki

    1976-01-01

    The recent advance and application as well as the profitability of method of coating by curing with electron beam are reviewed. The acrylic prepolymers having two or more acryloyl radicals on side chains or at the end can be cured with electron beam, and have excellent characteristics. The technique to use acrylic esters and methacrylic esters as dilutant monomers has been developed. Mitsubishi Rayon Co., Ltd. is finishing asbestos slate boards and calcium silicate boards for prefabricated houses, utilizing an electron beam curing coating line. The line serves as a semicommercial production line having the capacity of continuously coating and curing boards of 1,200 mm by 2,400 mm. It is equipped with an electron beam accelerator of 500 kV x 65 mA (max. 100 mA), a conveyor running at speed of 5 to 100 m/min, and a curtain flow coater, a roller coater and the like. It can be cured rapidly at room temperature. The finished coatings have high cross-linking density and withstand particularly blocking, freezing and solvents. Its application to the coating of automotive parts by Suzuki Automobile Co. is briefly mentioned. (Iwakiri, K.)

  17. 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

  18. Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

    Directory of Open Access Journals (Sweden)

    Jose Augusto RODRIGUES

    2017-08-01

    Full Text Available Abstract The effect of restoration depth on the curing time of a conventional and two bulk-fill composite resins by measuring microhardness and the respective radiosity of the bottom surface of the specimen was investigated. 1-, 3- and 5-mm thick washers were filled with Surefil SDR Flow–U (SDR, Tetric EvoCeram Bulk Fill-IVA (TEC or Esthet-X HD–B1 (EHD, and cured with Bluephase® G2 for 40s. Additional 1-mm washers were filled with SDR, TEC or EHD, placed above the light sensor of MARC®, stacked with pre-cured 1-, 3- or 5-mm washer of respective material, and cured for 2.5~60s to mimic 2-, 4- and 6-mm thick composite curing. The sensor measured the radiosity (EB at the bottom of specimen stacks. Vickers hardness (VH was measured immediately at 5 locations with triplicate specimens. Nonlinear regression of VH vs EB by VH=α[1-exp(-EB/β] with all thickness shows that the values of α, maximum hardness, are 21.6±1.0 kg/mm2 for SDR, 38.3±0.6 kg/mm2 for TEC and 45.3±2.6 kg/mm2 for EHD, and the values of β, rate parameter, are 0.40±0.06 J/cm2 for SDR, 0.77±0.04 J/cm2 for TEC and 0.58±0.09 J/cm2 for EHD. The radiosity of the bottom surface was calculated when the bottom surface of each material attained 80% of α of each material. The curing times for each material are in agreement with manufacturer recommendation for thickness. It is possible to estimate time needed to cure composite resin of known depth adequately by the radiosity and microhardness of the bottom surface.

  19. Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites.

    Science.gov (United States)

    Rodrigues, Jose Augusto; Tenorio, Ilana Pais; Mello, Ginger Baranhuk Rabello de; Reis, André Figueiredo; Shen, Chiayi; Roulet, Jean-François

    2017-08-21

    The effect of restoration depth on the curing time of a conventional and two bulk-fill composite resins by measuring microhardness and the respective radiosity of the bottom surface of the specimen was investigated. 1-, 3- and 5-mm thick washers were filled with Surefil SDR Flow-U (SDR), Tetric EvoCeram Bulk Fill-IVA (TEC) or Esthet-X HD-B1 (EHD), and cured with Bluephase® G2 for 40s. Additional 1-mm washers were filled with SDR, TEC or EHD, placed above the light sensor of MARC®, stacked with pre-cured 1-, 3- or 5-mm washer of respective material, and cured for 2.5~60s to mimic 2-, 4- and 6-mm thick composite curing. The sensor measured the radiosity (EB) at the bottom of specimen stacks. Vickers hardness (VH) was measured immediately at 5 locations with triplicate specimens. Nonlinear regression of VH vs EB by VH=α[1-exp(-EB/β)] with all thickness shows that the values of α, maximum hardness, are 21.6±1.0 kg/mm2 for SDR, 38.3±0.6 kg/mm2 for TEC and 45.3±2.6 kg/mm2 for EHD, and the values of β, rate parameter, are 0.40±0.06 J/cm2 for SDR, 0.77±0.04 J/cm2 for TEC and 0.58±0.09 J/cm2 for EHD. The radiosity of the bottom surface was calculated when the bottom surface of each material attained 80% of α of each material. The curing times for each material are in agreement with manufacturer recommendation for thickness. It is possible to estimate time needed to cure composite resin of known depth adequately by the radiosity and microhardness of the bottom surface.

  20. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation

    DEFF Research Database (Denmark)

    Viswanathan, Venkatasubramanian; Hansen, Heine Anton; Nørskov, Jens K.

    2015-01-01

    evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates...... sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively....

  1. Intercommunication of factors the energy products and peroxidation at training

    Directory of Open Access Journals (Sweden)

    Evdokimov E.I.

    2012-03-01

    Full Text Available Influence of the training loading on the state of some parameters, characterizing the basic ways of power providing and lipid peroxidation is studied. In research took part 34 footballers in the age 19 - 25 years. Trainings were conducted in aerobic-anaerobic mode. It is set that as a result of training duration 90 minutes the endogenous antioxidant systems of man adequately get along at the processes of peroxidase. Meaningful correlative connections are exposed statistically between the intermediate products of carbohydrate, lipidic, albuminous exchange and lipid peroxidation.

  2. Applications of hydrogen peroxide in electrochemical technology

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Gallegos, Alberto Armando

    1998-12-01

    It is demonstrated that hydrogen peroxide can be produced with a current efficiency of 40-70% by the cathodic reduction of oxygen at a reticulated vitreous carbon electrode in a divided flow-cell using catholytes consisting of aqueous chloride or sulphate media, pH >>{sub 2}. The supporting electrolyte does not influence either the current efficiency for H{sub 2}O{sub 2} or its rate of production. The current efficiency for H{sub 2}O{sub 2} is not a strong function of the potential and this suggests that 2e- and 4e- reduction of oxygen occurs in parallel at different sites on the carbon surface. Voltammetry experiments showed that (a) the I-E response for oxygen reduction at pH >>{sub 2} is a function of the electrode surface and/or the supporting electrolyte; (b) both H{sub 2} evolution and oxygen reduction are retarded on carbon with increasing ionic strength; (c) the presence of ferrous ions lead to the homogeneous decomposition of H{sub 2}O{sub 2} away from the cathode surface but their effectiveness as a catalyst for this decomposition depends on their speciation in solution which changes during an electrolysis. The use of a three-dimensional electrode fabricated from reticulated vitreous carbon allows Fenton`s reagent to be electroproduced at a practical rate which makes possible the removal of organics in slightly acidic aqueous media. A wide range of highly toxic organic molecules (phenol, catechol, hydroquinone, p-benzoquinone, oxalic acid, aniline, cresol and amaranth) have been oxidised in mild conditions and a significant fraction of the organic carbon is evolved as CO{sub 2}. In all cases studied the initial chemical oxygen demand (COD) was depleted to levels higher than 85%, indicating a complete mineralisation of the organic pollutants. The life-time of the reticulated vitreous carbon cathode was demonstrated to be over 1000 hours during two and a half years of experiments. During this time the cathode performance was very good, leading to

  3. Microporous polyurethane-acrylamide film cured by electron beam irradiation

    International Nuclear Information System (INIS)

    Ando, Masayuki; Goto, Takakazu; Tsuchiya, Mitsuru; Uryu, Toshiyuki

    1988-01-01

    The morphology and aggregation structure of electron beam (EB)-cured microporous polyurethane-acrylamide film was investigated. The urethane-acrylamide prepolymer was synthesized by the reaction of poly(butylene adipate)diol, diphenylmethane diisocyanate, and N-(hydroxymethyl)acrylamide. It was found from scanning electron microscopy that the urethane-acrylamide film, which was prepared by using a methyl ethyl ketone and dimethylformamide (3:1 v/v) mixture as casting solvent, had a microporous structure with pore size of several micrometers, and that the morphology was fixed by EB irradiation. The pore volume of the EB-cured microporous film was determined to be about 460 mm 3 g -1 by mercury porosimetry. The micropores were not destroyed even after immersing in solvent, possibly because the cured film had high crystallinity and dense crosslinking. Moreover, it was found by X-ray photelectron spectroscopy that terminal portions of urethane-acrylamide were localized at the film surface. (author)

  4. Development of a modified dry curing process for beef.

    Science.gov (United States)

    Hayes, J E; Kenny, T A; Ward, P; Kerry, J P

    2007-11-01

    The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (PCured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), Pcured beef products with enhanced organoleptic quality and increased yields.

  5. Cost analysis of low energy electron accelerator for film curing

    International Nuclear Information System (INIS)

    Ochi, Masafumi

    2003-01-01

    Low energy electron accelerators are recognized as one of the advanced curing means of converting processes for films and papers. In the last three years the price of the accelerator equipment has been greatly reduced. The targeted application areas are mainly processes of curing inks, coatings, and adhesives to make packaging materials. The operating cost analyses were made for electron beam (EB) processes over the conventional ones without EB. Then three new proposals for cost reduction of EB processes are introduced. Also being developed are new EB chemistries such as coatings, laminating adhesives and inks. EB processes give instantaneous cure and EB chemistries are basically non solvent causing less VOC emission to the environment. These developments of both equipment and chemistries might have a potential to change conventional packaging film industries. (author)

  6. A combinaison of UV curing technology with ATL process

    Science.gov (United States)

    Balbzioui, I.; Hasiaoui, B.; Barbier, G.; L'hostis, G.; Laurent, F.; Ibrahim, A.; Durand, B.

    2017-10-01

    In order to reduce the time and the cost of manufacturing composite, UV curing technology combined with automated tape placement process (ATL) based on reverse approach by working with a fixed head was studied in this article. First, a brief description of the developed head placement is presented. Mechanical properties are then evaluated by varying process parameters, including compaction force and tape placement speed. Finally, a parametric study is carried out to identify suitable materials and process parameters to manufacture a photo composite material with high mechanical performances. The obtained results show that UV curing is a very good alternative for thermal polymerization because of its fast cure speed due to less dependency on temperature.

  7. Practical aspects of irradiance and energy in UV curing

    International Nuclear Information System (INIS)

    Stowe, R.W.

    1999-01-01

    The physical properties of UV-cured materials are substantially affected by the lamp systems used to cure them. The development of the intended properties, whether a varnish, an ink, or an adhesive, can depend on how well these lamp factors are designed and managed. The four key factors of UV exposure are: UV irradiance (or intensity), spectral distribution (wavelengths) of UV, effective energy (time-integrated UV irradiance), and infrared radiation. Inks and varnishes will exhibit very different response to peak irradiance or energy, as well as to different UV spectra. The ability to identify the various lamp characteristics and match them to the optical properties of the curable materials, widens the range in which UV curing is a faster, more efficient production process. This paper explores the reasons for clearly identifying these factors for process optimization

  8. Application of electron beam curing technology for paper products

    International Nuclear Information System (INIS)

    Takaharu Miura

    1999-01-01

    The electron beam (EB) curing technology has rapidly advanced in recent years. However there were few examples applying this technology to paper products. One reason comes from the high price of EB equipment and the other comes from the difficulty of controlling the irradiation which gives damages to paper. In spite of these problems, the EB cured coating layer shows remarkable features, such as solvent-resistance, water-resistance, heat-resistance and high smoothness using the drum casting technique. Concentrating on application of this technology to paper, we have already developed some products. For example, paper for printings (Super Mirror PN) and for white boards (Super Mirror WB) have been manufactured. In this presentation, we are going to introduce this EB curing technique and the products

  9. Electron beam curing of composites in North America

    International Nuclear Information System (INIS)

    Berejka, Anthony J.; Eberle, Cliff

    2002-01-01

    Electron beam curing of fiber-reinforced composites was explored over 30 years ago. Since then there have been developments in accelerator technology, in processes for handling materials presented to an accelerator, and in materials that can be used as matrix binders. In recent years in North America, Cooperative Research and Development Agreements (CRADAs) have been formed involving collaboration amongst materials suppliers, accelerator manufacturers and service providers, national laboratories, such as Oak Ridge National Laboratory, and interested potential users. The scope and status of these CRADAs are reviewed along with other recent developments in the electron beam curing of composites in North America. Innovative and proprietary materials technology has been developed and progress made toward implementing commercial practice. Significant market interest has developed in the military/aerospace industries that are finding the process and performance of electron beam cured composites to offer significant benefits

  10. Temperature and curing time affect composite sorption and solubility

    Directory of Open Access Journals (Sweden)

    Fabrício Luscino Alves de Castro

    2013-04-01

    Full Text Available Objective: This study evaluated the effect of temperature and curing time on composite sorption and solubility. Material and Methods: Seventy five specimens (8×2 mm were prepared using a commercial composite resin (ICE, SDI. Three temperatures (10°C, 25°C and 60°C and five curing times (5 s, 10 s, 20 s, 40 s and 60 s were evaluated. The specimens were weighed on an analytical balance three times: A: before storage (M1; B: 7 days after storage (M2; C: 7 days after storage plus 1 day of drying (M3. The storage solution consisted of 75% alcohol/25% water. Sorption and solubility were calculated using these three weights and specimen dimensions. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U Tests (α=5%. Results: The results showed that time, temperature and their interaction influenced the sorption and solubility of the composite (p0.05. The 60°C composite temperature led to lower values of sorption for all curing times when compared with the 10°C temperature (p0.05. Solubility was similar at 40 s and 60 s for all temperatures (p>0.05, but was higher at 10°C than at 60°C for all curing times (p0.05. Conclusions: In conclusion, higher temperatures or longer curing times led to lower sorption and solubility values for the composite tested; however, this trend was only significant in specific combinations of temperature and curing times.

  11. Mixed Field Modification of Thermally Cured Castor Oil Based Polyurethanes

    International Nuclear Information System (INIS)

    Mortley, A.

    2006-01-01

    Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanatee (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were subjected to a range of accumulated doses (0.0-3.0 MGy) produced by the mixed ionizing field of the SLOWPOKE-2 research reactor. The physico-mechanical properties of COPU, unirradiated and irradiated, were characterized by mechanical tests. Increased bond formation resulting from radiation-induced crosslinking was confirmed by favorable increases in mechanical properties and by solid-state 13 C -NMR and FTIR spectra

  12. 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

  13. Viral hepatitis B and C. Cure or treatment?

    Directory of Open Access Journals (Sweden)

    Dimitrios A. Kountouras

    2014-12-01

    Full Text Available HBV and HCV infections are among the most important global health problems; both represent also the leading cause of cirrhosis and HCC worldwide. HBV treatment cannot be considered cure but effective viral suppression can be achieved and remains the current principal goal of therapy. Talking about HCV treatment today equals to talking about total cure of the patient, with treatments of very high SVR rates, shorter if not shortest duration, minimal risk for resistance, pangenotypic and practically with no serious adverse events, no fibrosis or previous treatment status limitations, but also with a very high cost.

  14. Beliefs about the causes and cures of depression

    OpenAIRE

    Furnham, Adrian; Ritchie, William; Lay, Alixe

    2016-01-01

    Aims: To test whether the group would recognise both vignettes with having depression and that the favoured cure would be Psychotherapy/Talking Cure. Method: In all, 320 adults completed a two-part questionnaire. In the first part, they were given two vignettes describing a 30-year-old female and a 45-year-old male both with depression. They were asked what they thought (if anything) was wrong with the person and how they could best be helped. In the second part, they completed two ...

  15. 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.

  16. 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)

  17. Safety and sensory aspects of nitrite alternatives in meat curing

    International Nuclear Information System (INIS)

    Shahidi, F.; Pegg, R.B.

    1991-01-01

    The use of nitrite to cure meats (especially bacon) is viewed as undesirable, because it leads to the formation of carcinogenic nitrosamines. The amount of nitrite (10-40 ppm) associated with the cured colour and flavour is fairly harmless, and it is the larger amount, (100-200 ppm) added to preserve the meat, which is potentially harmful. This article reviews various preservatives which can be used in combination with low concentrations of nitrate. The authors consider that the use of lactate, of alternatively radiation sterilization, offers the best safe alternative to nitrate

  18. The chemistry of UV and BE radiation curing

    International Nuclear Information System (INIS)

    Garnett, J.L.

    1991-01-01

    The application of photopolymerisation (UV) and electron beams (EB) technologies in radiation rapid cure (PRC) processing is discussed. The chemistry associated with such reactions and the mechanisms of the processes are treated. The occurrence of concurrent grafting to substrate with radiation curing of films is shown to be an advantage in enhancing the properties of certain finished products. The parameters influencing the optimum grafting yield in such PRC processes are discussed. In many applications, the chemistry of such processes combined with the machine, specially for EB is shown. (author)

  19. The chemistry of UV and EB radiation curing

    International Nuclear Information System (INIS)

    Garnett, J.L.

    1987-01-01

    The application of photopolymerisation (UV) and electron beam (EB) technologies in radiation rapid cure (RRC) processing is discussed. The chemistry associated with such reactions and the mechanisms of the processes are treated. The occurrence of concurrent grafting to substrate with radiation curing of film is shown to be an advantage in enhancing the properties of certain finished products. The parameters influencing the optimum grafting yield in such RRC processes are discussed. In many applications, the chemistry of the process combined with the machine, expecially for EB, is shown a so-called ''turn-key'' operation. (author)

  20. Trends in the wide web converting markets for UV curing

    International Nuclear Information System (INIS)

    Fisher, R.

    1999-01-01

    As we prepare to enter a new decade, the use of ultraviolet (UV) energy to initiate the polymerization of coatings in the wide web segment of the Converting industry continues to increase. As is typical in the Converting industry, while many of the significant advances in technology have been developed around the world, they have been driven initially by the Western European markets. This was true with regards to the introduction of water-borne Pressure Sensitive Adhesives and thermal curing 100% solids silicone release coatings during the late 1970s and early 1980s, but this trend has changed with regards to the current state-of-the-art in UV curing

  1. Dr. William O. Coffee and his absorption cure for cataract.

    Science.gov (United States)

    Ferry, A P

    1989-08-01

    Dr. William O. Coffee was an ophthalmologist who conducted an office and mail-order practice in the Midwest from the 1880s until 1927. His main stock in trade was a self-discovered absorption cure for a variety of ocular diseases, with particular emphasis on the medical cure of cataracts. Dr. Coffee's career was a checkered one, marked by dubious credentials, exuberant self-promotion, unlikely and exaggerated claims of medical successes, plagiarism, and rejection by the medical "establishment." Certain parallels may be drawn between his activities and some currently observed practices in ophthalmology.

  2. Electron beam curing polyurethane acrylate oligomer in air

    International Nuclear Information System (INIS)

    Zhu, Zhenkang; Chen, Xing; Zhou, Jichun; Ma, Zue-Teh

    1988-01-01

    It has been found according to our synthesis that a novel kind of polyurethane acrylate oligomer can be cured by electron beam in the presence of oxygen, even at normal atomospheric levels, without any additives. Irradiation of the oligomer with substantially complete cure to a solid non-tacky state is quite remarkable. It has the same gel content (90 %) in air as in nitrogen at dose of 33 kGy. Double bond conversion of the oligomer is about 50 % by I.R. (author)

  3. 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.

  4. Effect of Terminalia chebula fruit extract on lipid peroxidation and ...

    African Journals Online (AJOL)

    SERVER

    2007-08-20

    Aug 20, 2007 ... products mainly edible vegetables and spices, have a key role in chemopreventers ... protein; dunit/minute/mg protein ; eµg/mg protein; fn moles of H2O2 ... induce peroxidation of cell membrane lipids (Bhattacharya et al., 1999). .... catalase – like activities in seminal plasma and spermatozoa. Int. J. Androl.

  5. Blood lipid metabolites and meat lipid peroxidation responses of ...

    African Journals Online (AJOL)

    Esnart Mukumbo

    2017-06-19

    Jun 19, 2017 ... Fat and protein contents of thigh muscle and abdominal fat weight were measured and reported. Chickens fed LPO had greater serum triacylglycerol and very low ... favour lipid peroxidation, inhibit synthesis of higher homologous of ... The ambient temperature was gradually decreased from 33 °C at first.

  6. Effect of americium-241 on luminous bacteria. Role of peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  7. Peroxidative damage of mitochondrial respiration is substrate-dependent

    Czech Academy of Sciences Publication Activity Database

    Endlicher, R.; Křiváková, P.; Rauchová, Hana; Nůsková, Hana; Červinková, Z.; Drahota, Zdeněk

    2009-01-01

    Roč. 58, č. 5 (2009), s. 685-692 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA303/06/1261 Institutional research plan: CEZ:AV0Z50110509 Keywords : mitochondrial enzymes * peroxidative damage * tert-butyl hydroperoxide Subject RIV: CE - Biochemistry Impact factor: 1.430, year: 2009

  8. Catalytic wet peroxide oxidation of formic acid in wastewater with ...

    African Journals Online (AJOL)

    2016-07-03

    Jul 3, 2016 ... The reaction was monitored by ATR FTIR by following the disappearance of the O-H ..... of hydrogen peroxide than other iron ions such as FeCl2, FeCl3, ..... HWANG D-S, LEE E-H, KIM K-W, LEE K-I and PARK S-J (1999).

  9. Combined effect of vanadium and nickel on lipid peroxidation and ...

    African Journals Online (AJOL)

    The exposure to nickel led to a significant decrease (p < 0.001) in SOD, GST activities in liver and GSH content in kidney and a significant (p < 0.001) increase in the hepatic MDA content and renal SOD activity. When the metals were administered in combination, the elevation of lipid peroxidation did not potentiate. However ...

  10. Hydrogen peroxide as a fungicide for fish culture

    Science.gov (United States)

    Dawson, V.K.; Rach, J.J.; Schreier, Theresa M.

    1994-01-01

    Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

  11. Sperm DNA damage in relation to lipid peroxidation following ...

    African Journals Online (AJOL)

    This study investigated the relationships between lipid peroxidation (LPO) and sperm DNA damage following freezing-thawing of boar semen in different extenders. The comet assay was used to measure the extent of sperm DNA damage in a cryoprotectant-free extender or in cryoprotectant-based extenders after single ...

  12. Effect of foliar application of salicylic acid, hydrogen peroxide

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 42; Issue 2. Effect of foliar application of salicylic acid, hydrogen peroxide and a xyloglucan oligosaccharide on capsiate content and gene expression associatedwith capsinoids synthesis in Capsicum annuum L. AY ZUNUN-PÉREZ T GUEVARA-FIGUEROA SN ...

  13. The kinetic study of oxidation of iodine by hydrogen peroxide

    International Nuclear Information System (INIS)

    Cantrel, L.; Chopin, J.

    1996-01-01

    Iodine chemistry is one of the most important subjects of research in the field of reactor safety because this element can form volatile species which represent a biological hazard for environment. As the iodine and the peroxide are both present in the sump of the containment in the event of a severe accident on a light water nuclear reactor, it can be important to improve the knowledge on the reaction of oxidation of iodine by hydrogen peroxide. The kinetics of iodine by hydrogen peroxide has been studied in acid solution using two different analytical methods. The first is a UV/Vis spectrophotometer which records the transmitted intensity at 460 nm as a function of time to follow the decrease of iodine concentration, the second is an amperometric method which permits to record the increase of iodine+1 with time thanks to the current of reduction of iodine+1 to molecular iodine. The iodine was generated by Dushman reaction and the series of investigations were made at 40 o C in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H + ions has been determined. The kinetics curves comprise two distinct chemical phases both for molecular iodine and for iodine+1. The relative importance of the two processes is connected to the initial concentrations of [I 2 ], [IO 3 - ], [H 2 O 2 ] and [H + ]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs

  14. Blood lipid metabolites and meat lipid peroxidation responses of ...

    African Journals Online (AJOL)

    Blood samples were collected from broilers to evaluate serum biochemical metabolites on day 41. Thigh meat samples were provided and analysed after 1, 5 and 10 days' storage to evaluate lipid peroxidation at the end of the experiment. Fat and protein contents of thigh muscle and abdominal fat weight were measured ...

  15. Hydrogen peroxide in exhaled air of healthy children: reference values

    NARCIS (Netherlands)

    Q. Jobsis (Quirijn); R.H. Raatgeep (Rolien); S.L. Schellekens; W.C.J. Hop (Wim); P.W.M. Hermans (Peter); J.C. de Jongste (Johan)

    1998-01-01

    textabstractAn increased content of hydrogen peroxide (H2O2), a marker of inflammation, has been described in the condensate of exhaled air from adults and children with inflammatory lung disorders, including asthma. However, the normal range of [H2O2] in the exhaled

  16. Plasma Lipid Peroxidation and Total Antioxidant Status among ...

    African Journals Online (AJOL)

    BACKGROUND: The oxidative modification hypothesis of atherosclerosis predicts that low density lipoprotein-cholesterol (LDL-C) oxidation is an early event in atherosclerosis and that oxidized LDL-C contributes to atherogenesis. OBJECTIVE: To determine a link, if any, between the plasma lipid peroxidation and total ...

  17. Sol – Gel synthesis and characterization of magnesium peroxide nanoparticles

    International Nuclear Information System (INIS)

    Jaison, J; Chan, Y S; Ashok raja, C; Balakumar, S

    2015-01-01

    Magnesium peroxide is an excellent source of oxygen in agriculture applications, for instance it is used in waste management as a material for soil bioremediation to remove contaminants from polluted underground water, biological wastes treatment to break down hydrocarbon, etc. In the present study, sol-gel synthesis of magnesium peroxide (MgO 2 ) nanoparticles is reported. Magnesium peroxide is odourless; fine peroxide which releases oxygen when reacts with water. During the sol-gel synthesis, the magnesium malonate intermediate is formed which was then calcinated to obtain MgO 2 nanoparticles. The synthesized nanoparticles were characterized using Thermo gravimetric -Differential Thermal Analysis (TG- DTA), X-Ray Diffraction studies (XRD) and High Resolution Transmission Electron Microscope (HRTEM). Our study provides a clear insight that the formation of magnesium malonate during the synthesis was due to the reaction between magnesium acetate, oxalic acid and ethanol. In our study, we can conclude that the calcination temperature has a strong influence on particle size, morphology, monodispersity and the chemistry of the particles. (paper)

  18. Can hydrogen peroxide and quercetin improve production of ...

    African Journals Online (AJOL)

    The aim of the present work was to determine if hydrogen peroxide in combination with quercetin or indole butyric acid, can modify some characteristics related to rooting and development in cuttings of Eucalyptus grandis x Eucalyptus urophylla. Cuttings were periodically evaluated at 30, 60 and 90 days according to the ...

  19. Hydrogen peroxide and radiation water chemistry of boiling water reactors

    International Nuclear Information System (INIS)

    Ibe, E.; Watanabe, A.; Endo, M.; Takahashi, M.; Karasawa, H.

    1991-01-01

    G-values and rate constants at elevated temperature are reviewed and updated for computer simulation of water radiolysis in BWRs. Quantitative relationship between g-values of H 2 and OH was found out to govern numerically the radiolytic environment in the BWR primary system. Thermal decomposition of hydrogen peroxide was measured in stagnant water in a quartz cell and the rate constant was determined at 2.4 x 10 -7 s -1 with the activation energy of 53.3 kJ/mol. Behaviors of hydrogen peroxide under HWC simulated with updated variables were consistent with plant observation at Forsmark 1 and 2. The most likely decomposition scheme of hydrogen peroxide at surface was identified as H 2 O 2 → H + HO 2 . Based on the surface decomposition process, actual level of hydrogen peroxide was estimated at 200-400 ppb under NWC condition from measured at BWR sampling stations. The estimation was consistent with the numerical simulation of BWR water radiolysis with updated variables. (author)

  20. Desiccation-induced changes in viability, lipid peroxidation and ...

    African Journals Online (AJOL)

    user

    2012-05-31

    May 31, 2012 ... Key words: Intermediate seeds, desiccation, reactive oxygen species, antioxidant enzymes, lipid peroxidation,. Mimusops ... between ROS production and cell defenses determines ... needed for reduction of dehydroascorbate, which is .... was calculated using the extinction coefficient (6.2 mM-1cm-1) for.

  1. Electrochemical reduction of hydrogen peroxide on stainless steel

    Indian Academy of Sciences (India)

    Administrator

    wide range of industrial processes such as food processing (e.g. in the ... tron transfer effect of mitochondria.4 These radicals. (reactive .... of H2O2 without undergoing fouling or poisoning due to any inter- .... adsorbed OHads species was shown operative at po- tentials of .... Douglass W C 2003 Hydrogen peroxide medical.

  2. The basic chemistry and photochemistry behind hydrogen peroxide tooth whitening

    NARCIS (Netherlands)

    Young, N.D.; Fairley, P.D.; Mohan, V.; Jumeaux, C.

    2013-01-01

    Tooth whitening using hydrogen peroxide gel formulation is a complexprocess which involves both chemistry and physics, and there is still some controversy about the efficiency of whitening processes, particularly with respect to the roles of temperature and irradiation with light. In this work we

  3. The curing behavior and properties of phthalonitrile resins using ionic liquids as a new class of curing agents

    Directory of Open Access Journals (Sweden)

    K. Cheng

    2017-11-01

    Full Text Available Binary blends composed of 1,3-bis (3,4-dicyanophenoxy benzene (3BOCN and ionic liquids (ILs with different molecular structures were prepared. The curing behavior of these 3BOCN/ILs blends were studied by thermogravimetric analysis (TGA, differential scanning calorimetry (DSC and rheological analysis. The study suggested that the blends possessed a wide processing window and the structures of ILs (anion, cation and alkyl chain length at cation had an effect on curing behavior. The 3BOCN/[EPy]BF4 resins were prepared at elevated temperature. IR spectra of the resins showed that there were triazine and isoindoline formed in curing process. The TGA and dynamic mechanical analysis (DMA revealed that the resins have excellent thermal stability together with high storage modulus and high glass transition temperature (Tg. Dielectric properties, long term oxidative aging and water uptake measurements of the resins suggested the IL brought some unique properties to the resins.

  4. Muscle individual phospholipid classes throughout the processing of dry-cured ham: influence of pre-cure freezing.

    Science.gov (United States)

    Pérez-Palacios, Trinidad; Ruiz, Jorge; Dewettinck, Koen; Le, Thien Trung; Antequera, Teresa

    2010-03-01

    This paper aims to study the profile of phospholipid (PL) classes of Iberian ham throughout its processing and the changes it underwent due to the influence of the pre-cure freezing treatment. The general profile of each PL class did not vary during the ripening stage. Phosphatidylcholine (PC) showed the highest proportion, followed by phosphatidyletanolamine (PE) and phosphatidylserine (PS) and phosphatidylinositol (PI) being the minor PL. The four PL classes were highly hydrolysed during the salting stage and their degradation continued during the rest of the processing. Pre-cure freezing of Iberian ham influenced the levels of the four PL classes at the initial stage, all of them being higher in refrigerated (R) than in pre-cure frozen (F) hams. Moreover, the pattern of hydrolysis was not the same in these two groups. Copyright 2009 Elsevier Ltd. All rights reserved.

  5. Effects of Chemical Curing Temperature and Time on the Properties of Liquefied Wood based As-cured Precursors and Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Junbo Shang

    2015-09-01

    Full Text Available Liquefied wood based as-cured precursors and carbon fibers prepared by different chemical curing processes were carried out to investigate the effects of curing temperature and time on the thermostability and microstructure of liquefied wood based precursors, the tensile strength of carbon fibers as well. The primary fibers can be converted into precursors with high performance by directly heating at target curing temperature. With the temperature and duration increasing, the numbers of methylene bonds in precursors increased, resulting in the enhancement of cross-linkages among molecular chains and then the improvement of thermostability of precursors. Carbon fibers prepared from as-cured precursors (curing temperature 95 oC, curing time 3h had the minimum value of the average interlayer spacing (d002, it also showed the highest tensile strength, almost 800 MPa, which can be classified as fibers of general grade.

  6. LIPID PEROXIDATION AND JOB STRESS IN DENTAL HEALTHCARE WORKERS

    Directory of Open Access Journals (Sweden)

    S. V. Melnikova

    2014-04-01

    Full Text Available This study devoted to the lipid peroxidation indices in dentists target group as a marker of psycho-emotional state. We revealed increase in the level of TBA-active products in female and male dentists during job stress. There was strong decrease in level of TBA-active products in control group of dentist that study during the lectures. Activation of lipid peroxidation in dentists during dentist examination can be considered as non-specific component of reactions towards the stressors of professional activities. We also revealed that the initial level of TBA-active products in female and male dentists before the outpatient dental reception was higher than that of dentists that study before lectures. This is indicates the mobilization of sympathetic nervous system before beginning of the working day. The contents of the level of TBA-active products in the oral fluid of female and male dentists after dental examination significantly increased, whereas these indices decreased in the group of dentists that study after the lectures. The increasing of TBA-active products in dentists after outpatient dental reception was by 42.5 % and 77 % higher compared with a group of dentists that study in the lecture classes. The results of correlation analysis suggest the influence of lipid peroxidation processes on the cardiovascular and blood system of dentists during job stress. Activation of lipid peroxidation in dentists during dental examination can be considered as non-specific component of the body's response to stressors influence in professional activities. Key words: dentists, activation of lipid peroxidation, psychoemotional stress, job stress.

  7. Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

    Science.gov (United States)

    Valdez, T. I.; Narayanan, S. R.

    2001-01-01

    This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

  8. Effect of curing time on microstructure and mechanical strength ...

    Indian Academy of Sciences (India)

    4 group is charge-balanced by alkali cations (typically Na. + and/or. K. +) available in the alkaline ... years, the use of different alumino-silicate materials have been performed: natural .... 48h of thermal treatment. After this curing age, the flexu-.

  9. Realtime 3D stress measurement in curing epoxy packaging

    DEFF Research Database (Denmark)

    Richter, Jacob; Hyldgård, A.; Birkelund, Karen

    2007-01-01

    This paper presents a novel method to characterize stress in microsystem packaging. A circular p-type piezoresistor is implemented on a (001) silicon chip. We use the circular stress sensor to determine the packaging induced stress in a polystyrene tube filled with epoxy. The epoxy curing process...

  10. Antimony to Cure Visceral Leishmaniasis Unresponsive to Liposomal Amphotericin B.

    Directory of Open Access Journals (Sweden)

    Gloria Morizot

    2016-01-01

    Full Text Available We report on 4 patients (1 immunocompetent, 3 immunosuppressed in whom visceral leishmaniasis had become unresponsive to (or had relapsed after treatment with appropriate doses of liposomal amphotericin B. Under close follow-up, full courses of pentavalent antimony were administered without life-threatening adverse events and resulted in rapid and sustained clinical and parasitological cure.

  11. Sodium nitrite: the "cure" for nitric oxide insufficiency.

    Science.gov (United States)

    Parthasarathy, Deepa K; Bryan, Nathan S

    2012-11-01

    This process of "curing" food is a long practice that dates back thousands of years long before refrigeration or food safety regulations. Today food safety and mass manufacturing are dependent upon safe and effective means to cure and preserve foods including meats. Nitrite remains the most effective curing agent to prevent food spoilage and bacterial contamination. Despite decades of rigorous research on its safety and efficacy as a curing agent, it is still regarded by many as a toxic undesirable food additive. However, research within the biomedical science community has revealed enormous therapeutic benefits of nitrite that is currently being developed as novel therapies for conditions associated with nitric oxide (NO) insufficiency. Much of the same biochemistry that has been understood for decades in the meat industry has been rediscovered in human physiology. This review will highlight the fundamental biochemistry of nitrite in human physiology and highlight the risk benefit evaluation surrounding nitrite in food and meat products. Foods or diets enriched with nitrite can have profound positive health benefits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. effect of light curing unit characteristics on light intensity output

    African Journals Online (AJOL)

    2013-09-09

    Sep 9, 2013 ... in Nairobi and their effect on light intensity output, depth of cure (DOC) and ... result in gradual reduction in the energy output of ..... of LED lights are compared with QTH lights could ... influence on the SMH of dark shades.

  13. Hot embossing of microstructures on addition curing polydimethylsiloxane films

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Yu, Liyun; Hassouneh, Suzan Sager

    2013-01-01

    The aim of this research work is to establish a hot embossing process for addition curing vinyl-terminated polydimethylsiloxane (PDMS), which are thermosetting elastomers, based on the existing and widely applied technology for thermoplasts. To our knowledge, no known technologies or processes...

  14. Industrial potential for application of radiation curing in Pakistan

    International Nuclear Information System (INIS)

    Ahmed, S.

    1991-01-01

    Potential applications of radiation curing of coating are in the field of wood and wood products, drying of printing inks, ceramics (roof and floor tiles) and textiles. Pakistan a 'timber deficit' country needs to improve her wood, plywood, hardboard and particle board to make for shortage of quality wood. Imports of wood and wood products are in excess of 3000 million rupees. Radiation curing can be applied and itexcels over heat treatment. Whereas costs of high energy units (500 KeV) with scanning type are rather high, low energy (100-175 KeV) flat beam self-shielded units costing 200,000 US$ are available. For developing countries ultraviolet (UV) curing is ideally suited because of its low price, flexibility and simplicity in handling. Alternately, multipurpose bunker type facility such as 500 KeV current mA can be utilized in carrying out heat-shrinkables production, irradiation of cable and wire and curing of coatings on wood and wood products. (author)

  15. Bacterial spoilage of meat and cured meat products

    NARCIS (Netherlands)

    Borch, E.; Kant-Muermans, M.L.T.; Blixt, Y.

    1996-01-01

    The influence of environmental factors (product composition and storage conditions) on the selection, growth rate and metabolic activity of the bacterial flora is presented for meat (pork and beef) and cooked, cured meat products. The predominant bacteria associated with spoilage of refrigerated

  16. Influence of curing regimes on compressive strength of ultra high

    Indian Academy of Sciences (India)

    The present paper is aimed to identify an efficient curing regime for ultra high performance concrete (UHPC), to achieve a target compressive strength more than 150 MPa, using indigenous materials. The thermal regime plays a vital role due to the limited fineness of ingredients and low water/binder ratio. By activation of the ...

  17. Radiation cure technology used in inks and coatings

    International Nuclear Information System (INIS)

    Ravijst, J.-P.

    1995-01-01

    The radiation cure technology in inks and coatings by ultraviolet light (UV) and electron beam (EB) was introduced. The technology is the only one which meets the 3-E rules. An advantage of this technology is that a wide range of substrates can be printed such as paper, card, metal and even heat sensitive plastics

  18. The Era of HIV Cure Research | Michael | Annals of Ibadan ...

    African Journals Online (AJOL)

    Timothy Ray Brown is widely referred to as the first HIV patient to be cured of the disease. He received a CCR5 deficient bone marrow transplant as a treatment for Acute Myeloid Leukemia, with HAART controlled HIV-1 infection at the background. Seven years after the transplant, and discontinuation of HAART, he has been ...

  19. Towards an HIV cure: a global scientific strategy

    NARCIS (Netherlands)

    Deeks, Steven G.; Autran, Brigitte; Berkhout, Ben; Benkirane, Monsef; Cairns, Scott; Chomont, Nicolas; Chun, Tae-Wook; Churchill, Melissa; Di Mascio, Michele; Katlama, Christine; Lafeuillade, Alain; Landay, Alan; Lederman, Michael; Lewin, Sharon R.; Maldarelli, Frank; Margolis, David; Markowitz, Martin; Martinez-Picado, Javier; Mullins, James I.; Mellors, John; Moreno, Santiago; O'Doherty, Una; Palmer, Sarah; Penicaud, Marie-Capucine; Peterlin, Matija; Poli, Guido; Routy, Jean-Pierre; Rouzioux, Christine; Silvestri, Guido; Stevenson, Mario; Telenti, Amalio; van Lint, Carine; Verdin, Eric; Woolfrey, Ann; Zaia, John; Barré-Sinoussi, Françoise

    2012-01-01

    Given the limitations of antiretroviral therapy and recent advances in our understanding of HIV persistence during effective treatment, there is a growing recognition that a cure for HIV infection is both needed and feasible. The International AIDS Society convened a group of international experts

  20. Quantification of salt concentrations in cured pork by computed tomography

    DEFF Research Database (Denmark)

    Vestergaard, Christian Sylvest; Risum, Jørgen; Adler-Nissen, Jens

    2004-01-01

    Eight pork loin samples were mounted in Plexiglas cylinders and cured for five days. Samples were scanned by computed tomography (CT) once every 24 h. At the end of the experiment, the cylinders were cut in 1 cm sections and analyzed for chloride. From image analysis of the CT images, concentration...

  1. Toxicity studies in rats fed nature cure bitters | Aniagu | African ...

    African Journals Online (AJOL)

    Graded doses of Nature Cure Bitters (NCB) were administered daily (100, 200 and 400 mg/kg p.o) to rats for 28 days and the effects on body weight, organ weight, clinical signs, gross pathology, haematology, histology and serum biochemical parameters were evaluated. The relative weights of the heart, liver and testes of ...

  2. The statistics of dose/cure relationships for irradiated tumours

    International Nuclear Information System (INIS)

    Porter, E.H.

    1980-01-01

    Attention is given to the statistical analysis of dose/cure experiments. The simplest possible theory is developed in detail with special attention to experimental design and to the range of validity of the methods advocated. Explanations are aimed at the mathematics-tolerant, not at the mathematician. (author)

  3. Preliminary study on solar-assisted tobacco curing in Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Bamrungwong, S [Chiang Mai Univ.; Suchinda, B; Malila, D

    1982-04-01

    A solar heating system for assisting flue curing of Virginia tobacco leaf was studied. The equipment consisted of a brick and mortar tobacco curing barn of 3.6 m/sup 3/ volume. The solar air heater of 2.8 m/sup 2/ was a non-focus type, made from corrugated galvanized stel sheet coated with flat-black paint. The collector had a single glass cover on top and a 25 mm layer of styrofoam at the bottom. Electrical heating was utilized inside the bar to simulate the main heat source. The system under study had no thermal storage, therefore it was extremely difficult to regulate the temperature inside the barn precisely. Consequently, the solar assisting mode is not recommended during the yellowing stage of curing where very precise temperature control is required. Utilization of solar energy during other stages of curing showed a saving of the main conventional energy up to 33 to 15 percent. The average thermal efficiencies of the collector varied from 70 percent at high flow rate to 67 percent at low flow rate. 6 references.

  4. 9 CFR 319.104 - Cured pork products.

    Science.gov (United States)

    2010-01-01

    ... Product-X% of Weight is Added Ingredients,” and “Ham with Natural Juices.” In addition to the binders... AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION DEFINITIONS AND STANDARDS OF IDENTITY OR COMPOSITION Cured Meats, Unsmoked and...

  5. 7 CFR 29.6002 - Air-cured.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... resulting from the application of artificial heat. ...

  6. Surgical cure ofthe Wolff-Parkinson-White syndrome a comparison ...

    African Journals Online (AJOL)

    Surgical cure ofthe Wolff-Parkinson-White syndrome a comparison oftwo techniques. u. o. VON OPPELL, R. N. SCOTT MILLAR, D. A. MILNE. TABLE!. Characteristics of WPW patients referred for surgical ablation of their aberrant atrioventricular pathways. Patient population and methods. We' retrospectively reviewed 19 ...

  7. Evaluation of curing compound application time on concrete surface durability.

    Science.gov (United States)

    2015-03-01

    The effect of curing compound application time after concrete finishing was examined in the study. Times of 30 minutes, 2 hours and 4 hours were considered and repeatability was evaluated with comparisons to a Phase I portion of the study. Scaling re...

  8. Delayed Microbial Cure of Lymphogranuloma Venereum Proctitis with Doxycycline Treatment

    NARCIS (Netherlands)

    de Vries, H.J.C.; Smelov, V.; Middelburg, J.G.; Pleijster, J.; Speksnijder, A.G.; Morré, S.A.

    2009-01-01

    Microbial cure of chlamydia proctitis (lymphogranuloma venereum [LGV] and non-LGV) with doxycycline treatment was evaluated by chlamydia DNA and RNA persistence in anal swab specimens. In LGV proctitis, RNA persisted for up to 16 days. In non-LGV chlamydia proctitis, DNA was undetectable after 7

  9. Curing Student Underachievement: Clinical Practice for School Leaders

    Science.gov (United States)

    Esbrandt, Philip; Hayes, Bruce

    2011-01-01

    "Cure Student Underachievement" is the culmination of the authors' research, practice, and experience as principals, superintendents, graduate professors, and consultants in efforts to improve school performance and increase student achievement. Searching for the real causes of underperformance, the authors explored problem-solving strategies in…

  10. Reproductive indices of Merino rams fed sun-cured Leucaena ...

    African Journals Online (AJOL)

    Reproductive indices of Merino rams fed sun-cured Leucaena leucocephala forage. I.V. Nsahlai, B.K. Byebwa, M.L.K. Bonsi. Abstract. (South African J of Animal Science, 2000, 30, Supplement 1: 111-112). Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  11. A study on the influence of curing on the strength of a standard grade concrete mix

    OpenAIRE

    Krishna Rao M.V.; Kumar Rathish P.; Khan Azhar M.

    2010-01-01

    Curing is essential if concrete is to perform the intended function over the design life of the structure while excessive curing time may lead to the escalation of the construction cost of the project and unnecessary delays. Where there is a scarcity of water and on sloping surfaces where curing with water is difficult and in cases where large areas like pavements have to be cured, the use of curing compound may be resorted to. The parameters of the study include the curing period [1, 3, 7, 1...

  12. Application conditions for ester cured alkaline phenolic resin sand

    Directory of Open Access Journals (Sweden)

    Ren-he Huang

    2016-07-01

    Full Text Available Five organic esters with different curing speeds: propylene carbonate (i.e. high-speed ester A; 1, 4-butyrolactone; glycerol triacetate (i.e. medium-speed ester B; glycerol diacetate; dibasic ester (DBE (i.e. low-speed ester C, were chosen to react with alkaline phenolic resin to analyze the application conditions of ester cured alkaline phenolic resin. The relationships between the curing performances of the resin (including pH value, gel pH value, gel time of resin solution, heat release rate of the curing reaction and tensile strength of the resin sand and the amount of added organic ester and curing temperature were investigated. The results indicated the following: (1 The optimal added amount of organic ester should be 25wt.%-30wt.% of alkaline phenolic resin and it must be above 20wt.%-50 wt.% of the organic ester hydrolysis amount. (2 High-speed ester A (propylene carbonate has a higher curing speed than 1, 4-butyrolactone, and they were both used as high-speed esters. Glycerol diacetate is not a high-speed ester in alkaline phenolic resin although it was used as a high-speed ester in ester cured sodium silicate sand; glycerol diacetate and glycerol triacetate can be used as medium-speed esters in alkaline phenolic resin. (3 High-speed ester A, medium-speed ester B (glycerol triacetate and low-speed ester C (dibasic ester, i.e., DBE should be used below 15 ìC, 35 ìC and 50 ìC, respectively. High-speed ester A or low-speed ester C should not be used alone but mixed with medium-speed ester B to improve the strength of the resin sand. (4 There should be a suitable solid content (generally 45wt.%-65wt.% of resin, alkali content (generally 10wt.%-15wt.% of resin and viscosity of alkaline phenolic resin (generally 50-300 mPa≤s in the preparation of alkaline phenolic resin. Finally, the technique conditions of alkaline phenolic resin preparation and the application principles of organic ester were discussed.

  13. Economic evaluation of five curing processes for wood coatings

    International Nuclear Information System (INIS)

    Martinez M, I.

    1996-01-01

    In this work we study the economic feasibility of five methods for curing coatings over sheet wood products. Each year, Mexico is producing more than 40 millions of square meters of wood panels, but the demand is of the range of 58 millions of square meters of this product. Two millions are expended after they are coated, and 38 millions without coating, they are coated artisanilly when they are used to make pieces of furniture. The technical characteristics and the costs involved in each one of five methods of curing, are described. Investments involved with each method are processed to establish: fixed costs, variable costs, equilibrium point, and others. Initial investment, coasts and revenues are processed to determine the income statement pro-form, the projected statement of change in financial position, the projected working capital, the projected balance sheet, the cash-flow, and some economical and financial indicators for each one of the five curing methods. With this information, the internal rate of return (IRR) is determined, and used to compare the economic worth of each of the five methods. The five methods are profitable, because all they have a IRR greater than the opportunity cost of capital (15%) of projects with similar characteristics. Despite, with each one of the five methods, the capital invested is recoverable, and profits can be obtained; curing by ultraviolet light or by electron beam, let recover the investment in less than two years, require fewer dollars for investment, and have a IRR of 135% and 111% respectively. Besides ultraviolet light or electron beam curing processes, pollute less with volatile solvents, use the energy efficiently, have greater production rate, and the coating obtained have better quality than with the other three methods. (Author)

  14. Properties of ambient cured blended alkali activated cement concrete

    Science.gov (United States)

    Talha Junaid, M.

    2017-11-01

    This paper presents results of the development and strength properties of ambient-cured alkali activated geopolymer concrete (GPC). The study looks at the strength properties, such as compressive strength, splitting tensile strength, and elastic modulus of such concretes and its dependency on various parameters. The parameters studied in this work are the type and proportions of pre-cursor materials, type of activator and their respective ratios and the curing time. Two types of pre-cursor material; low calcium fly ash (FA) and ground granulated blast furnace slag (GGBFS) were activated using different proportions of sodium silicate and sodium hydroxide solutions. The results indicate that ambient cured geopolymer concrete can be manufactured to match strength properties of ordinary Portland cement concrete (OPC). The strength properties of GPC are dependent on the type and ratio of activator and the proportion of GGBFS used. Increasing the percentage of GGBFS increased the compressive and tensile strengths, while reducing the setting time of the mix. The effect of GGBFS on strength was more pronounced in mixes that contained sodium silicate as activator solution. Unlike OPC, ambient-cured GPC containing sodium silicate gain most of their strength in the first 7 days and there is no change in strength thereafter. However, GPC mixes not containing sodium silicate only achieve a fraction of their strength at 7 days and extended curing is required for such concretes to gain full strength. The results also indicate that the elastic modulus values of GPC mixes without sodium silicate are comparable to OPC while mixes with sodium silicate have elastic modulus values much lower than ordinary concrete.

  15. Protective mechanisms against peptide and protein peroxides generated by singlet oxygen

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan

    2004-01-01

    or detoxify such peroxides. It is shown that catalase, horseradish peroxidase, and Cu/Zn superoxide dismutase do not react rapidly with these peroxides. Oxymyoglobin and oxyhemoglobin, but not the met (Fe3+) forms of these proteins, react with peptide but not protein, peroxides with oxidation of the heme iron...

  16. Microwave and thermal curing of an epoxy resin for microelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, K. [Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Pavuluri, S.K.; Leonard, M.T.; Desmulliez, M.P.Y. [MIcroSystems Engineering Centre (MISEC), Institute of Signals, Sensors and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Arrighi, V., E-mail: v.arrighi@hw.ac.uk [Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2015-09-20

    Graphical abstract: - Highlights: • Thermal and microwave curing of a commercial epoxy resin EO1080 are compared. • Microwave curing increases cure rate and does not adversely affect properties. • The curing of EO1080 is generally autocatalytic but deviates at high conversion. • Microwave radiation has a more complex effect on curing kinetics. - Abstract: Microwave curing of thermosetting polymers has a number of advantages to natural or thermal oven curing and is considered a cost-effective alternative. Here we present a detailed study of a commercially available epoxy resin, EO1080. Samples that are thermally cured are compared to curing using a recently developed modular microwave processing system. For commercial purposes it is crucial to demonstrate that microwave curing does not adversely affect the thermal and chemical properties of the material. Therefore, the kinetics of cure and various post cure properties of the resin are investigated. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) analysis shows no significant difference between the conventionally and microwave cured samples. Differential scanning calorimetry (DSC) is used to monitor the kinetics of the curing reaction, as well as determine the thermal and ageing properties of the material. As expected, the rate of curing is higher when using microwave energy and we attempt to quantify differences compared to conventional thermal curing. No change in glass transition temperature (T{sub g}) is observed. For the first time, enthalpy relaxation measurements performed on conventional and microwave cured samples are reported and these indicate similar ageing properties at any given temperature under T{sub g}.

  17. Microwave and thermal curing of an epoxy resin for microelectronic applications

    International Nuclear Information System (INIS)

    Johnston, K.; Pavuluri, S.K.; Leonard, M.T.; Desmulliez, M.P.Y.; Arrighi, V.

    2015-01-01

    Graphical abstract: - Highlights: • Thermal and microwave curing of a commercial epoxy resin EO1080 are compared. • Microwave curing increases cure rate and does not adversely affect properties. • The curing of EO1080 is generally autocatalytic but deviates at high conversion. • Microwave radiation has a more complex effect on curing kinetics. - Abstract: Microwave curing of thermosetting polymers has a number of advantages to natural or thermal oven curing and is considered a cost-effective alternative. Here we present a detailed study of a commercially available epoxy resin, EO1080. Samples that are thermally cured are compared to curing using a recently developed modular microwave processing system. For commercial purposes it is crucial to demonstrate that microwave curing does not adversely affect the thermal and chemical properties of the material. Therefore, the kinetics of cure and various post cure properties of the resin are investigated. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) analysis shows no significant difference between the conventionally and microwave cured samples. Differential scanning calorimetry (DSC) is used to monitor the kinetics of the curing reaction, as well as determine the thermal and ageing properties of the material. As expected, the rate of curing is higher when using microwave energy and we attempt to quantify differences compared to conventional thermal curing. No change in glass transition temperature (T g ) is observed. For the first time, enthalpy relaxation measurements performed on conventional and microwave cured samples are reported and these indicate similar ageing properties at any given temperature under T g

  18. A comparative study on two explosive acetone peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Egorshev, V. Yu.; Sinditskii, V.P., E-mail: vps@rctu.ru; Smirnov, S.P.

    2013-12-20

    Highlights: • The most accurate heats of DADP and TATP sublimation were evaluated from experimental vapor pressures in a widened temperature range. • DADP is more volatile while more thermally stable peroxide than TATP. • DADP reveals lesser sensitivity to drop-weight impact, flame temperature, burning rate, and initiating efficiency as compared with TATP. - Abstract: Two explosive cyclic acetone peroxides, diacetone diperoxide (DADP) and triacetone triperoxide (TATP) have been studied in respect of thermal decomposition, burning behavior, impact sensitivity, and initiating efficiency. Using the glass Bourdon gauge technique, the vapor pressures of TATP and DADP were determined over the temperature range 75–144 °C and 67–120 °C, respectively. The kinetic parameters of decomposition of the peroxides in the gas phase have been obtained in the temperature interval of 140–200 °C. The decomposition of both DADP and TATP followed the first-order reaction to high degrees of decay with close activation energies of 159.2 kJ/mol (38.0 kcal/mol) and 165.8 kJ/mol (39.6 kcal/mol), respectively. The decomposition rate constants of DADP were found to be approximately 2 times less than those of TATP. The linear burning rate of DADP measured in a constant-pressure window bomb appeared to be approximately 5 times less than that of TATP. Temperature profiles in the combustion wave were measured at subatmospheric pressures with the help of thin tungsten-rhenium thermocouples. The leading reaction on combustion of both volatile peroxides was assumed to occur in the gas phase. Kinetic parameters of the leading reaction derived from the combustion data showed a good agreement with kinetic parameters of low-temperature thermal decomposition extrapolated to the high-temperature flame zone. In the drop-weight impact test, DADP appeared to be notably less sensitive peroxide than TATP. No deflagration-to-detonation transition was observed when RDX was attempted to explode by

  19. Influence of curing rate on softening in ethanol, degree of conversion, and wear of resin composite

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Asmussen, Erik

    2011-01-01

    PURPOSE: To investigate the effect of curing rate on softening in ethanol, degree of conversion, and wear of resin composites. METHOD: With a given energy density and for each of two different light-curing units (QTH or LED), the curing rate was reduced by modulating the curing mode. Thus......, the irradiation of resin composite specimens (Filtek Z250, Tetric Ceram, Esthet-X) was performed in a continuous curing mode and in a pulse-delay curing mode. Wallace hardness was used to determine the softening of resin composite after storage in ethanol. Degree of conversion was determined by infrared...... exposed to the pulse-delay curing mode were softer than resin composites exposed to continuous cure (Pconversion (P

  20. 'Every disease has its cure': faith and HIV therapies in Islamic ...

    African Journals Online (AJOL)

    'Every disease has its cure': faith and HIV therapies in Islamic northern Nigeria. ... African Journal of AIDS Research ... a divine cure for HIV exists, many Muslim patients on ART, and the predominantly Muslim biomedical staff who treat them, ...

  1. Solid-state /sup 13/C NMR study of cured resorcinol-formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    Lippmaa, H.; Samoson, A.

    1988-08-01

    The curing process generally follows the pattern observed in the stage of prepolymer formation. Catalysts (NaOH, hexa, Mg(OCOCH/sub 3/)/sub 2/) that have no substantial influence on the isomeric composition of the resorcinol-formaldehyde prepolymers, do not affect the isomeric composition of the cured resins to any significant extent either. Isomeric composition of the cured resins depends mostly on the presence of water during the curing process, necessary for depolymerisation of the added paraformaldehyde. Curing in the melt leads to enhanced 2-substitution in the 1,3-dihydroxybenzene rings. In the /sup 13/C NMR spectra of cured powdered samples, the tendency of 5-methylresorcinol to form oligomers with a higher degree of 2-substitution than resorcinol is clearly apparent. Polycondensation process continues in the powdered resins after initial curing until complete consumption of all formaldehyde. Curing of phenol-formaldehyde resols proceeds through intermediate dimethylene ether formation.

  2. Current and future market of UV/EB curing in Thailand

    International Nuclear Information System (INIS)

    Suda Kiatkamjornwong; Aran Hanseubsai

    1999-01-01

    Current status and future market of UV/EB curing in Thailand were presented. Included number of printing houses, export, main export market and the role of radiation curing in printing and packaging industries of Thailand

  3. E-Beam-Cured Layered-Silicate and Spherical Silica Epoxy Nanocomposites (Preprint)

    National Research Council Canada - National Science Library

    Chen, Chenggang; Anderson, David P

    2007-01-01

    .... The nanofillers can be two dimensional (layered-silicate) and zero dimensional (spherical silica). Both the spherical silica epoxy nanocomposite and the layered-silicate epoxy nanocomposite can be cured to a high degree of curing...

  4. Differential sensitivity of cellular membranes to peroxidative processes

    International Nuclear Information System (INIS)

    Huijbers, W.A.R.

    1976-01-01

    A description is given of a morphological and cytochemical investigation into the effects of both vitamin E deficiency and X-irradiation on the ultrastructure and enzyme activities of several cellular membranes, particularly the plasma membrane and the membranes of lysosomes, mitochondria and endoplasmic reticulum. In the vitamin E deficient situation, the radicals and peroxides only originate near mitochondria and endoplasmic reticulum, so that these membrane systems suffer from changes. After irradiation of the liver of both the control duckling and the deficient duckling, radicals originate in all parts of the cell. Due to their high content of lipids and cholesterols, peroxides will occur mainly in plasma membranes and lysosomal membranes. Moreover, in these membranes there is hardly any protection by vitamin E

  5. Ultraviolet- and sunlight-induced lipid peroxidation in liposomal membrane

    International Nuclear Information System (INIS)

    Mandal, T.K.; Chatterjee, S.N.

    1980-01-01

    Ultraviolet radiation and sunlight caused lipid peroxidation in the liposomal membrane (as detected by measurement of the oxidation index, A 233 /A 215 , and the amount of malondialdehyde formed) and made the membrane leaky (as revealed by the release of the trapped chromate anions). The oxidation index and the formation of malondialdehyde increased linearly with increasing dose of radiation and depended significantly on the dose rate. The effects were smaller in liposomes derived from Vibrio cholerae phospholipid than in those derived from egg lecithin. The effects of the radiation dose and dose rate on hemolysis and peroxidation (MDA formation) of the erythrocyte membrane followed a similar pattern. A direct correlation between the percentage leakage of chromate (Y) and the oxidation index (X) of the liposomal system was obtained as Y = 236.5 x X

  6. Assay to detect lipid peroxidation upon exposure to nanoparticles.

    Science.gov (United States)

    Potter, Timothy M; Neun, Barry W; Stern, Stephan T

    2011-01-01

    This chapter describes a method for the analysis of human hepatocarcinoma cells (HEP G2) for lipid peroxidation products, such as malondialdehyde (MDA), following treatment with nanoparticle formulations. Oxidative stress has been identified as a likely mechanism of nanoparticle toxicity, and cell-based in vitro systems for evaluation of nanoparticle-induced oxidative stress are widely considered to be an important component of biocompatibility screens. The products of lipid peroxidation, lipid hydroperoxides, and aldehydes, such as MDA, can be measured via a thiobarbituric acid reactive substances (TBARS) assay. In this assay, which can be performed in cell culture or in cell lysate, MDA combines with thiobarbituric acid (TBA) to form a fluorescent adduct that can be detected at an excitation wavelength of 530 nm and an emission wavelength of 550 nm. The results are then expressed as MDA equivalents, normalized to total cellular protein (determined by Bradford assay).

  7. Hydrogen Peroxide: A Key Chemical for Today's Sustainable Development.

    Science.gov (United States)

    Ciriminna, Rosaria; Albanese, Lorenzo; Meneguzzo, Francesco; Pagliaro, Mario

    2016-12-20

    The global utilization of hydrogen peroxide, a green oxidant that decomposes in water and oxygen, has gone from 0.5 million tonnes per year three decades ago to 4.5 million tonnes per year in 2014, and is still climbing. With the aim of expanding the utilization of this eminent green chemical across different industrial and civil sectors, the production and use of hydrogen peroxide as a green industrial oxidant is reviewed herein to provide an overview of the explosive growth of its industrial use over the last three decades and of the state of the art in its industrial manufacture, with important details of what determines the viability of the direct production from oxygen and hydrogen compared with the traditional auto-oxidation process. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Study on the agglomeration kinetics of uranium peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, M.; Mojica Rodriguez, L.A. [CEA, Centre de Marcoule, Nuclear Energy Division, RadioChemistry and Process Department, 17171, Bagnols-sur-Ceze 30207 (France); Muhr, H.; Plasari, E. [Reaction and Process Engineering Laboratory, CNRS, University of Lorraine. 1 rue Grandville, BP 20451, Nancy 54001 (France); Auger, F. [Areva Mines/SEPA. 2 route de Lavaugrasse, Bessines-sur-Gartempe 87250 (France)

    2016-07-01

    Considering the previous study dealing with thermodynamic and kinetic phenomena (nucleation and crystal growth) during the uranium peroxide precipitation, this work focuses on the agglomeration mechanism. It provides the results obtained from the experiments carried out in a mixed suspension - mixed product removal (MSMPR) mixer operating at steady state. The influence of the operating parameters on the uranium peroxide agglomerates was studied in order to identify the agglomeration kernel. The method is based on the resolution of the population balance equation using the method of moments and the experimental particle size distributions. The results lead to a size-independent kernel directly proportional to the crystal growth rate. Under the stirring conditions studied, the agglomeration appears to be significantly reduced by mixing which results in a kernel inversely proportional to the average shear rate. The agglomeration kinetic law obtained in this study will be used for the process modelling in a further study. (authors)

  9. Carbon catalysts for electrochemical hydrogen peroxide production in acidic media

    DEFF Research Database (Denmark)

    Čolić, Viktor; Yang, Sungeun; Révay, Zsolt

    2018-01-01

    Hydrogen peroxide is a commodity chemical, as it is an environmentally friendly oxidant. The electrochemical production of H2O2 from oxygen and water by the reduction of oxygen is of great interest, as it would allow the decentralized, on-site, production of pure H2O2. The ability to run...... the reaction in an acidic electrolyte with high performance is particularly important, as it would allow the use of polymer solid electrolytes and the production of pH-neutral hydrogen peroxide. Carbon catalysts, which are cheap, abundant, durable and can be highly selective show promise as potential catalysts...... for such systems. In this work, we examine the electrocatalytic performance and properties of seven commercially available carbon materials for H2O2 production by oxygen electroreduction. We show that the faradaic efficiencies for the reaction lie in a wide range of 18-82% for different carbon catalysts. In order...

  10. Study on the agglomeration kinetics of uranium peroxide

    International Nuclear Information System (INIS)

    Bertrand, M.; Mojica Rodriguez, L.A.; Muhr, H.; Plasari, E.; Auger, F.

    2016-01-01

    Considering the previous study dealing with thermodynamic and kinetic phenomena (nucleation and crystal growth) during the uranium peroxide precipitation, this work focuses on the agglomeration mechanism. It provides the results obtained from the experiments carried out in a mixed suspension - mixed product removal (MSMPR) mixer operating at steady state. The influence of the operating parameters on the uranium peroxide agglomerates was studied in order to identify the agglomeration kernel. The method is based on the resolution of the population balance equation using the method of moments and the experimental particle size distributions. The results lead to a size-independent kernel directly proportional to the crystal growth rate. Under the stirring conditions studied, the agglomeration appears to be significantly reduced by mixing which results in a kernel inversely proportional to the average shear rate. The agglomeration kinetic law obtained in this study will be used for the process modelling in a further study. (authors)

  11. Lycopene control of benzophenone-sensitized lipid peroxidation

    Science.gov (United States)

    Cvetković, Dragan; Marković, Dejan

    2012-05-01

    Lycopene antioxidant activity in the presence of two different mixtures of phospholipids in hexane solution, under continuous regime of UV-irradiation from three different ranges (UV-A, UV-B, and UV-C) has been evaluated in this work. Lycopene expected role was to control lipid peroxidation, by scavenging free radicals generated by UV-irradiation, in the presence and in the absence of selected photosensitizer, benzophenone. This work shows that lycopene undergoes to UV-induced destruction (bleaching), highly dependent on the incident photons energy input, more expressed in the presence than in the absence of benzophenone. The further increase ("excess") of its bleaching is undoubtedly related to the further increase of its antioxidant activity in the presence of benzophenone, having the same cause: increase of (phospholipids peroxidation) chain-breaking activities.

  12. Preparation of water soluble chitosan by hydrolysis using hydrogen peroxide.

    Science.gov (United States)

    Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

    2013-08-01

    Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Study on mechanism of decreased lipid peroxide by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Okazoe, Yoko; Akimaru, Kunihiro; Sato, E.F.; Utsumi, Kozo.

    1991-01-01

    We examined the effect of SOD on lipid peroxidation in biomembrane from V.E-deficient rats, in order to study the mechanism of increased SOD activities and decreased lipid peroxide by low dose irradiation. The following results were obtained. i. Active oxygen (O 2 - ) strongly enhances lipid peroxidations in biomembrane with the Fe 3+ as catalyst. ii. SOD evidently inhibits lipid peroxidations under above conditions. iii. We suggested that the effect of SOD enhanced by low dose irradiation results in inhibition of lipid peroxidation. (author)

  14. Cellular effects of halogen blue light from dental curing unit

    International Nuclear Information System (INIS)

    Trosic, I.; Pavicic, I.; Jukic, S.

    2008-01-01

    Full text: Halogen curing lights are the most frequently used polymerization source in dental offices. Light-cured bonding systems have become increasingly popular among clinicians because they offer a number of advantages over self-cured adhesives. The effort to increase polymerization quality releases the commercially available high power light density dental curing units. Emitted visible blue light belongs to the range of nonionizing radiation. Common concern in both, patients and dentist grows with regard to the unfavorable effects on the pulp tissue. The aim of study was to evaluate the time and dose dependence effect of halogen light curing unit (Elipar TriLight, ESPE Dental AG, Germany) at the disposed condition modes in vitro. A quartz-tungsten-halogen light source emits radiation of the wavelengths between 400 and 515 nm. This halogen blue light source operates in the three illumination modes, medium (M), exponential (E) and standard (S), and five illumination times. The total irradiance or the light intensity was measured by the light intensity control area on the control panel of device and mean light intensity given by manufacturer was 800 m W/cm 2 . Continuous culture of V79 cells was illuminated in triplicate. The influence of medium mode (M), exponential (E) and standard (S) illumination during 20, 40 and 80 sec on the cell viability, colony forming ability and proliferation of V79 cell culture was investigated. Trypan blue exclusion test was used to determine cell viability, both, in the treated and control cell samples. Colony forming ability was assessed for each exposure time and mode by colony count on post-exposure day 7. Cell proliferation was determined by cell counts for each time and mode of exposure during five post-exposure days. Statistical difference were determined at p<0.05 (Statistica 7.0, StatSoft Inc., USA). Viability of cells was not affected by blue light in view of exposure time and modes. Regardless to exposure or illumination

  15. Light output from six battery operated dental curing lights

    Energy Technology Data Exchange (ETDEWEB)

    Shimokawa, Carlos Alberto Kenji, E-mail: carlos.shimokawa@usp.br [University of São Paulo, School of Dentistry, Restorative Dentistry, Avenida Professor Lineu Prestes, 2227, 05508-000, São Paulo, São Paulo (Brazil); Dalhousie University, Faculty of Dentistry, Dental Clinical Sciences, 5981 University Avenue, B3H 4R2, Halifax, Nova Scotia (Canada); Turbino, Míriam Lacalle, E-mail: miturbin@usp.br [University of São Paulo, School of Dentistry, Restorative Dentistry, Avenida Professor Lineu Prestes, 2227, 05508-000, São Paulo, São Paulo (Brazil); Harlow, Jessie Eudora, E-mail: jessie.harlow@dal.ca [Dalhousie University, Faculty of Dentistry, Dental Clinical Sciences, 5981 University Avenue, B3H 4R2, Halifax, Nova Scotia (Canada); Price, Hannah Louise, E-mail: hannlprice@gmail.com [Dalhousie University, Faculty of Dentistry, Dental Clinical Sciences, 5981 University Avenue, B3H 4R2, Halifax, Nova Scotia (Canada); Price, Richard Bengt, E-mail: richard.price@dal.ca [Dalhousie University, School of Biomedical Engineering and Faculty of Dentistry, 5981 University Avenue, B3H 4R2, Halifax, Nova Scotia (Canada)

    2016-12-01

    Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20 second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p < 0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p < 0.01). The Bluephase G2 and Translux 2 Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs. - Highlights: • The six LCUs delivered significantly different light output characteristics. • The use of a single irradiance value does not adequately describe the light output from a curing light. • Small differences in the tip area, or how it is defined, will have a large effect on the calculated irradiance. • In some cases there were large portions of the light tip that emitted less than 400 mW/cm². • The radiant

  16. Light output from six battery operated dental curing lights

    International Nuclear Information System (INIS)

    Shimokawa, Carlos Alberto Kenji; Turbino, Míriam Lacalle; Harlow, Jessie Eudora; Price, Hannah Louise; Price, Richard Bengt

    2016-01-01

    Light Curing Units (LCUs) are used daily in almost every dental office to photocure resins, but because the light is so bright, the user is unable to tell visually if there are any differences between different LCUs. This study evaluated the light output from six dental LCUs: Elipar Deep Cure-S (3M ESPE), Bluephase G2 (Ivoclar Vivadent), Translux 2Wave (Heraeus Kulzer), Optilight Prime (Gnatus), Slim Blast (First Medica) and Led.B (Guilin Woodpecker) with a fully charged battery, after 50, and again after 100, 20 second light exposures. For each situation, the radiant power was measured 10 times with a laboratory-grade power meter. Then, the emission spectrum was measured using a fiber-optic spectrometer followed by an analysis of the light beam profile. It was found there were significant differences in the LCU power and the irradiance values between the LCUs (p < 0.01). The Optilight Prime and Slim Blast LCUs showed a significant reduction in light output after a 50 and 100 exposures, while Bluephase G2 exhibited a significant reduction only after 100 exposures (p < 0.01). The Bluephase G2 and Translux 2 Wave delivered an emission spectrum that had two distinct wavelength emission peaks. Only the Elipar Deep Cure-S and Bluephase G2 LCUs displayed homogeneous light beam profiles, the other LCUs exhibited highly non-homogeneous light beam profiles. It was concluded that contemporary LCUs could have very different light output characteristics. Both manufacturers and researchers should provide more information about the light output from LCUs. - Highlights: • The six LCUs delivered significantly different light output characteristics. • The use of a single irradiance value does not adequately describe the light output from a curing light. • Small differences in the tip area, or how it is defined, will have a large effect on the calculated irradiance. • In some cases there were large portions of the light tip that emitted less than 400 mW/cm². • The radiant

  17. The Effect of Rubber Mixing Process on The Curing Characteristics of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Abu Hasan

    2013-04-01

    Full Text Available This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.

  18. Strength development of concrete made with recycled glass aggregates subjected to frost curing conditions

    OpenAIRE

    Poutos, Konstantinos; Nwaubani, Sunny

    2013-01-01

    An experimental investigation was undertaken to study whether the strength behavior of concrete made with glass aggregate differed significantly from that made with natural aggregates when concretes cured in low temperatures. The aim of the research work presented is to examine the strength behavior of glass concrete when cured under freezing conditions at -15°C and -10°C. The results showed that when glass concrete is cured at low curing temperature, the 28 day compressive strength is higher...

  19. Ionizing radiation post-curing of objects produced by stereolithography and other methods

    Science.gov (United States)

    Howell, David H.; Eberle, Claude C.; Janke, Christopher J.

    2000-01-01

    An object comprised of a curable material and formed by stereolithography or another three-dimensional prototyping method, in which the object has undergone initial curing, is subjected to post-curing by ionizing radiation, such as an electron beam having a predetermined beam output energy, which is applied in a predetermined dosage and at a predetermined dose rate. The post-cured object exhibits a property profile which is superior to that which existed prior to the ionizing radiation post-curing.

  20. Evaluating the use of renewable fuel sources to heat flue-cured tobacco barns

    OpenAIRE

    Brown, Robert T

    2018-01-01

    Evaluating the use of renewable fuel sources to heat flue-cured tobacco barns Robert Taylor Brown ABSTRACT The curing of flue-cured tobacco (Nicotiana tabacum L.) is an energy intensive process and represents a significant portion of the overall cost of production. Given the goal of the industry to reduce the environmental footprint of tobacco production and the energy demand of curing, attention has been directed to explore options for the use of renewable fuels for heating to...

  1. Glycerophosphate-dependent hydrogen peroxide production by rat liver mitochondria

    Czech Academy of Sciences Publication Activity Database

    Ješina, Pavel; Kholová, D.; Bolehovská, R.; Červinková, Z.; Drahota, Zdeněk; Houštěk, Josef

    2004-01-01

    Roč. 53, č. 3 (2004), s. 305-310 ISSN 0862-8408 R&D Projects: GA ČR GA303/03/0799; GA MŠk OC 918.50 Institutional research plan: CEZ:AV0Z5011922 Keywords : mitochondrial glycerophosphate dehydrogenace * triiodothyronine * hydrogen peroxide Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.140, year: 2004

  2. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2008-01-01

    Roč. 56, - (2008), s. 7925-7928 ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  3. Role of lipid peroxidation in pathogenesis of senile cataract

    Directory of Open Access Journals (Sweden)

    Kisić Bojana

    2009-01-01

    Full Text Available Background /Aim. Cataract is a structural, biochemical and optical change in the eye lens, which changes transmission and refraction of light rays reducing keenness and clarity of a figure on the retina. Its occurrence is highest in older people, over the age of 65 (45.9%, thus a certain degree of opacification exists practically in all people over the 70. Our research was directed to measuring of lipid peroxidation products in cataract lenses involved in early stages of cataractogenesis through oxidative stress and in the development of mature cataract. Methods. Clinical and biochemical research was carried out in 101 patients with cataract, 46 women and 55 men. The average age of the group was 72.47 (ґ = 7.98. According to the cataract maturity degree the patients were classified into two groups as follows: cataracta senilis incipiens (n = 41 and cataracta senilis matura (n = 60. Measuring of diene conjugates was carried out by spectrophotometer. Fluorescent lipid peroxidation products were measured by a spectrofluorophotometer, and malondialdehyde (MDA concentration was measured by colorimeter as a product of a reaction with thiobarbituric acid (TBA. Result. Significantly higher diene conjugated concentration in lenses was measured in the patients with the diagnosis cataracta senilis incipiens (p < 0.001 as well as the intensity of fluorescent iminopropens (p < 0.001. Significantly higher MDA concentration in lens (p < 0.001 was measured in the patients with cataracta senilis matura. Conclusion. The lens structure changes caused by lipid peroxidation can, with other risk factors present, influence the occurrence and development of mature cataract. Some cataract types show different lipid peroxidation intensity with the most distinct changes in cataract which started as corticonuclear.

  4. The kinetic study of oxidation of iodine by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Cantrel, L [Institut de Protection et de Surete Nucleaire, IPNS, CEN Cadarache, Saint Paul lez Durance (France); Chopin, J [Laboratoire d` Electrochimie Inorganique, ENSSPICAM, Marseille (France)

    1996-12-01

    Iodine chemistry is one of the most important subjects of research in the field of reactor safety because this element can form volatile species which represent a biological hazard for environment. As the iodine and the peroxide are both present in the sump of the containment in the event of a severe accident on a light water nuclear reactor, it can be important to improve the knowledge on the reaction of oxidation of iodine by hydrogen peroxide. The kinetics of iodine by hydrogen peroxide has been studied in acid solution using two different analytical methods. The first is a UV/Vis spectrophotometer which records the transmitted intensity at 460 nm as a function of time to follow the decrease of iodine concentration, the second is an amperometric method which permits to record the increase of iodine+1 with time thanks to the current of reduction of iodine+1 to molecular iodine. The iodine was generated by Dushman reaction and the series of investigations were made at 40{sup o}C in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H{sup +} ions has been determined. The kinetics curves comprise two distinct chemical phases both for molecular iodine and for iodine+1. The relative importance of the two processes is connected to the initial concentrations of [I{sub 2}], [IO{sub 3}{sup -}], [H{sub 2}O{sub 2}] and [H{sup +}]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs.

  5. Determination of peracetic acid and hydrogen peroxide in the mixture

    OpenAIRE

    Bodiroga Milanka; Ognjanović Jasminka

    2002-01-01

    Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2) in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A). Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction...

  6. Allergic Contact Dermatitis to Benzoyl Peroxide Resembling Impetigo.

    Science.gov (United States)

    Kim, Changhyun; Craiglow, Brittany G; Watsky, Kalman L; Antaya, Richard J

    2015-01-01

    A 17-year-old boy presented with recurring severe dermatitis of the face of 5-months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris. © 2015 Wiley Periodicals, Inc.

  7. The basic chemistry and photochemistry behind hydrogen peroxide tooth whitening

    OpenAIRE

    Young, N.D.; Fairley, P.D.; Mohan, V.; Jumeaux, C.

    2013-01-01

    Tooth whitening using hydrogen peroxide gel formulation is a complexprocess which involves both chemistry and physics, and there is still some controversy about the efficiency of whitening processes, particularly with respect to the roles of temperature and irradiation with light. In this work we avoid the complications of the physics bystudying the basic interactions between whitening agents and stainmolecules in simple solutions. We demonstrate that blue light irradiation has a clear and la...

  8. Oxidation of hydrogen peroxide by [Ni (cyclam)] in aqueous acidic ...

    Indian Academy of Sciences (India)

    Oxidation of hydrogen peroxide by tris(2,2 -bipyridine) and tris(4,4 -dimethyl-2,2 - bipyridine) complexes of osmium(III), iron(III), ruthenium(III), and nickel(III) studied in acidic and neutral aqueous media, show an inverse acid depen- dence over the pH the range 6.0–8.5.12 Kinetic mea- surements with an excess of H2O2 ...

  9. Effect of exercise on lipid peroxidation in student soccer players

    OpenAIRE

    Puspaningtyas, Desty Ervira; Afriani, Yuni; Mahfida, Silvi Lailatul; Kushartanti, Wara; Farmawati, Arta

    2018-01-01

    Training is conducted to improve physiological functions that can support improvementof cardio-respiratory function (O2max). However, intensive training can lead to oxidativestress, which can contribute to health problems. The purpose of this study was to evaluatethe effect of training on serum lipid peroxidation levels in student soccer players. Thestudy was pre-experimental study with a one-shot case design conducted in April 2014.Twelve student soccer players from UGM who chosen by purposi...

  10. Continuous precipitation of uranium peroxide in process pilot plant

    International Nuclear Information System (INIS)

    Quinelato, A.L.

    1990-01-01

    An experimental study on uranium peroxide precipitation has been carried out with the objective to evaluate the influence of the main process parameters with a technological approach. The uraniferous solution used was obtained from the hydrometallurgical processing of an ore from Itataia - CE. Studies were developed in two distinct experimental stages. In the first stage, the precipitation was investigated by means of laboratory batch tests and, in the second stage, by means of continuous operation in a process pilot plant. (author)

  11. Membrane lipid peroxidation by UV-A: Mechanism and implications

    International Nuclear Information System (INIS)

    Bose, B.; Agarwal, S.; Chatterjee, S.N.

    1990-01-01

    UV-A produced a dose-dependent linear increase of lipid peroxidation in liposomal membrane, as detected by the assay of (i) conjugated dienes, (ii) lipid hydroperoxides, (iii) malondialdehydes (MDA), and (iv) the fluorescent adducts formed by the reaction of MDA with glycine and also a linear dose-dependent increase of [ 14 C]glucose efflux from the liposomes. UV-A-induced MDA production could not be inhibited by any significant degree by sodium formate, dimethyl sulfoxide, EDTA, or superoxide dismutase but was very significantly inhibited by butylated hydroxytoluene, alpha-tocopherol, sodium azide, L-histidine, dimethylfuran, and beta-carotene. MDA formation increased with an increase in the D 2 O content in water, leading to a maximal amount of nearly 50% enhancement of lipid peroxidation in 100% D 2 O vis-a-vis water used as dispersion medium. The experimental findings indicate the involvement of singlet oxygen as the initiator of the UV-A-induced lipid peroxidation

  12. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

    Directory of Open Access Journals (Sweden)

    Marcos S. Rabelo

    2008-08-01

    Full Text Available Molybdenum catalyzed peroxide bleaching (PMo Stage consists of pulp treatment with hydrogen peroxide under acidic conditions in the presence of a molybdenum catalyst. Molybdenum is applied in catalytic doses (50-200 mg/kg pulp and may originate from various sources, including (NH46Mo7O24.4H2O, Na2MoO4.2H2O, siliconmolybdate, etc. This work is aimed at optimizing the PMo stage and evaluating its industrial application in the OAZDP sequence. Optimum PMo stage conditions for bleaching eucalyptus pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/adt Mo and 5 kg/adt H2O2. The PMo stage was more efficient to remove pulp hexenuronic acids than lignin. Its efficiency decreased with increasing pH in the range of 1.5-5.5, while it increased with increasing temperature and peroxide and molybdenum doses. The application of the PMo stage as replacement for the A-stage of the AZDP sequence significantly decreased chlorine dioxide demand. The PMo stage caused a decrease of 20-30% in the generation of organically bound chlorine. The quality parameters of the pulp produced during the PMo stage mill trial were comparable to those obtained with the reference A-stage.

  13. Levels of oxidative damage and lipid peroxidation in thyroid neoplasia.

    LENUS (Irish Health Repository)

    Young, Orla

    2012-02-01

    BACKGROUND: This study assessed the presence of oxidative damage and lipid peroxidation in thyroid neoplasia. METHODS: Using tissue microarrays and immunohistochemistry, we assessed levels of DNA damage (8-oxo-dG) and lipid peroxidation (4-HNE) in 71 follicular thyroid adenoma (FTA), 45 papillary thyroid carcinoma (PTC), and 17 follicular thyroid carcinoma (FTC) and matched normal thyroid tissue. RESULTS: Cytoplasmic 8-oxo-dG and 4-HNE expression was significantly higher in FTA, FTC, and PTC tissue compared to matched normal tissue (all p values < .001). Similarly, elevated nuclear levels of 8-oxo-dG were seen in all in FTA, FTC, and PTC tissue compared to matched normal (p values < .07, < .001, < .001, respectively). In contrast, a higher level of 4-HNE expression was detected in normal thyroid tissue compared with matched tumor tissue (p < .001 for all groups). Comparing all 3 groups, 4-HNE levels were higher than 8-oxo-dG levels (p < .001 for all groups) except that cytoplasmic levels of 8-oxo-dG were higher than 4-HNE in all (p < .001). These results were independent of proliferation status. CONCLUSION: High levels of DNA damage and lipid peroxidation in benign and malignant thyroid neoplasia indicates this damage is an early event that may influence disease progression.

  14. Effect of irradiation of lipid peroxidation in serum, 2

    International Nuclear Information System (INIS)

    Haisa, Yoshio

    1976-01-01

    With blood obtained from patients irradiated for cervical uterine cancer (consisting of 4 cases of Stage I, 5 cases of Stage II and 4 cases of Stage III), changes of blood picture, serum lipid weight and serum lipid peroxide accompanying irradiation were studied on 3 occasions, before, during and after the irradiation. The following results were obtained. Serum lipid and serum lipid peroxide were found to increase along with the advance of uterine cancer from Stage I to II and III. At the termination of irradiation the serum lipid and serum lipid peroxide in the cases of cervical uterine cancer at Stage III were found to have recovered to close to the levels before irradiation, but in the other cases these values tended to increase with irradiation. Except the termination of irradiation treatment of cervical uterine cancer of Stage III, the decrease of leucocyte count has a mutual relationship with the increase of serum thiobarbituric acid (TBA), so that change in the serum TBA level can be assumed to be a criterion for irradiation injury. (auth.)

  15. Effect of curing methods, packaging and gamma irradiation on the weight loss and dry matter percent of garlic during curing and storage

    International Nuclear Information System (INIS)

    Mahmoud, A.A.; El-Oksh, I.I.; Farag, S.E.A.

    1988-01-01

    The Egyptian garlic plants, showed higher percent of weight loss at 17 or 27 days from curing compared to those of Chinese plants. The curing period of 17 days seemed satisfactory for the Egyptian cultivar, whereas, 27 days seemed to be enough for the Chinese garlic. No significant differences were observed between common and shaded curing methods in weight loss per cent. The Chinese garlic contained higher dry matter percentage than those of the Egyptian cultivar. Shaded cured plants of the two cultivars contained higher dry matter percent than those subjected to the common curing methods. Irradiation of garlic bulbs, shaded curing method and sack packaging decreased, in general the weight loss during storage in comparison with other treatments

  16. Effect of light-curing units on the thermal expansion of resin nanocomposites.

    Science.gov (United States)

    Park, Jeong-Kil; Hur, Bock; Ko, Ching-Chang; García-Godoy, Franklin; Kim, Hyung-Il; Kwon, Yong Hoon

    2010-12-01

    To examine the thermal expansion of resin nanocomposites after light-curing using different light-curing units. Four different resin nanocomposites and four different light-curing units [quartz-tungsten-halogen (QTH), light emitting diode (LED), laser, and plasma arc] were chosen. Metal dies were filled with resin to make specimens and light-cured. The light intensity and light-curing time of the QTH and LED light-curing units were 1000 mW/cm2 and 40 seconds, 700 mW/cm2 and 40 seconds for the laser, and 1600 mW/cm2 and 3 seconds for the plasma arc. The coefficient of thermal expansion (CTE) was evaluated using a thermomechanical analyzer (TMA) at temperatures ranging from 30-80 degrees C. The CTE of the resin nanocomposites tested ranged from 28.5 to 65.8 (x 10(-6)/ degrees C), depending on the product and type of light-curing unit used. Among the specimens, Grandio showed the lowest CTE. The specimens cured using the plasma arc unit (Apollo 95E) showed the highest CTE. There was a linear correlation between the CTE and filler content (vol%) (R: -0.94-0.99 depending on the light-curing unit). The results may suggest a careful selection of the light-curing unit because there was more expansion in the specimens cured using the plasma arc unit than those cured by the other units.

  17. Optimal temperature profiles for minimum residual stress in the cure process of polymer composites

    CSIR Research Space (South Africa)

    Gopal, AK

    2000-01-01

    Full Text Available include the minimum residual stresses, minimum cure cycle lime and full degree of cure. The development of residual stresses during the cure cycle is one of the most important problems as they affect the strength and the mechanical properties of the final...

  18. 21 CFR 170.60 - Nitrites and/or nitrates in curing premixes.

    Science.gov (United States)

    2010-04-01

    ... premixes, may continue to be used under prior sanctions in the commercial curing of meat and meat products... that apply to meat curing preparations for the home curing of meat and meat products, including poultry and wild game. To assure safe use of such ingredients the labeling of the premixes shall bear...

  19. Nitrophenylboronic acids as highly chemoselective probes to detect hydrogen peroxide in foods and agricultural products.

    Science.gov (United States)

    Lu, Chun-Ping; Lin, Chieh-Ti; Chang, Ching-Ming; Wu, Shih-Hsiung; Lo, Lee-Chiang

    2011-11-09

    Hydrogen peroxide is commonly used in the food processing industry as a chlorine-free bleaching and sterilizing agent, but excessive amounts of residual hydrogen peroxide have led to cases of food poisoning. Here we describe the development of a novel nonenzymatic colorimetric method for the determination of residual hydrogen peroxide in foods and agricultural products. Nitrophenylboronic acids chemoselectively react with hydrogen peroxide under alkaline conditions to produce yellow nitrophenolates. Of the three nitrophenylboronic acid isomers tested, the p-isomer displayed the highest sensitivity for hydrogen peroxide and the fastest reaction kinetics. The reaction product, p-nitrophenolate, has an absorption maximum at 405 nm and a good linear correlation between the hydrogen peroxide concentration and the A(405) values was obtained. We successfully applied this convenient and rapid method for hydrogen peroxide determination to samples of dried bean curds and disposable chopsticks, thereby demonstrating its potential in foods and agricultural industries.

  20. Toxigenic aspergilli and penicillia isolated from aged, cured meats.

    Science.gov (United States)

    Wu, M T; Ayres, J C; Koehler, P E

    1974-12-01

    Eighty-nine cultures of Aspergillus and 54 cultures of Penicillium isolated from aged, cured meats were tested for toxicity to chicken embryos. Two of 22 isolates of A. ruber, 5 of 28 A. repens, 2 of 12 A. sydowi, 1 of 12 A. restrictus, 2 of 7 A. amstelodami, 1 of 2 A. chevalieri, and an A. fumigatus isolate exhibited toxicity. Similarly, 2 of 15 isolates of P. expansum, 1 of 3 P. notatum, 1 of 2 P. brevi-compactum, and 1 of 8 Penicillium spp. were found to be the most toxic. Among these fungi, the chloroform extract from the growth of an A. sydowi isolate showed the greatest toxicity. There was no direct or indirect evidence that aged, cured meats contain toxic metabolites.

  1. Poison or cure: meanings of medication in schizophrenia.

    Science.gov (United States)

    Rosenfield, Paul J

    2007-01-01

    Antipsychotic medications provide tremendous relief to many individuals with schizophrenia, but can have significant costs, including adverse metabolic, neurological, and psychological effects. Prescribers and consumers of these medications often have different perceptions of the safety and utility of medications, ranging from "poison" to "cure." While much of the literature on the meaning of medication in schizophrenia discusses patients' negative perceptions of medication, poor insight, and other risk factors for nonadherence, a variety of additional factors should be considered, including both doctors' and patients' perspectives. Historical, cultural, and scientific, as well as individual factors, influence both the prescribing and taking of antipsychotic medications. The relationship between doctors and patients, as informed by these factors, plays a central role in the creation of the meanings of medications. An understanding of this relationship can help to establish more collaborative treatment relationships, beyond the dichotomy of poison or cure.

  2. Delbruck Prize Award: Insights into HIV Dynamics and Cure

    Science.gov (United States)

    Perelson, Alan S.

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of a phenomenon called post-treatment control (PTC) or functional cure of HIV-infection in which some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection. The model relies on an immune response and bistability to explain PTC. I will then generalize the model to explicitly include immunotherapy with monoclonal antibodies approved for use in cancer to show that one can induce PTC with a limited number of antibody infusions and compare model predictions with experiments in SIV infected macaques given immunotherapy. Lastly, I will argue that quantitative insights derived from models of HIV infection have and will continue to play an important role in medicine.

  3. Synthesis, characterization and photoinduced curing of polysulfones with (methacrylate functionalities

    Directory of Open Access Journals (Sweden)

    Cemil Dizman

    2010-06-01

    Full Text Available The UV-curable telechelic polysulfones with (methacrylate functionalities were synthesized by condensation polymerization and subsequent esterification. The final polymers and intermediates at various stages were characterized by 1H NMR, FT-ATR, and GPC. The oligomeric films prepared from the appropriate solutions containing these telechelics and 2,2-dimethoxy-2-phenylacetophenone (DMPA as the photoinitiator undergo rapid polymerization upon irradiation forming insoluble networks. The photo-curing behavior was investigated by photo-DSC and the effects of the molecular weight of the polysulfone precursor and type of functionality on the rate of polymerization and conversion were evaluated. Thermal properties of the photochemically cured films were studied by differential scanning calorimeter (DSC and thermal gravimetric analysis (TGA.

  4. Thermo-cured glass ionomer cements in restorative dentistry.

    Science.gov (United States)

    Gorseta, Kristina; Glavina, Domagoj

    2017-01-01

    Numerous positive properties of glass ionomer cements including biocompatibility, bioactivity, releasing of fluoride and good adhesion to hard dental tissue even under wet conditions and easy of handling are reasons for their wide use in paediatric and restorative dentistry. Their biggest drawbacks are the weaker mechanical properties. An important step forward in improving GIC's features is thermo-curing with the dental polymerization unit during setting of the material. Due to their slow setting characteristics the GIC is vulnerable to early exposure to moisture. After thermo curing, cements retain all the benefits of GIC with developed better mechanical properties, improved marginal adaptation, increased microhardness and shear bond strength. Adding external energy through thermocuring or ultrasound during the setting of conventional GIC is crucial to achieve faster and better initial mechanical properties. Further clinical studies are needed to confirm these findings.

  5. A nonparametric mixture model for cure rate estimation.

    Science.gov (United States)

    Peng, Y; Dear, K B

    2000-03-01

    Nonparametric methods have attracted less attention than their parametric counterparts for cure rate analysis. In this paper, we study a general nonparametric mixture model. The proportional hazards assumption is employed in modeling the effect of covariates on the failure time of patients who are not cured. The EM algorithm, the marginal likelihood approach, and multiple imputations are employed to estimate parameters of interest in the model. This model extends models and improves estimation methods proposed by other researchers. It also extends Cox's proportional hazards regression model by allowing a proportion of event-free patients and investigating covariate effects on that proportion. The model and its estimation method are investigated by simulations. An application to breast cancer data, including comparisons with previous analyses using a parametric model and an existing nonparametric model by other researchers, confirms the conclusions from the parametric model but not those from the existing nonparametric model.

  6. HIV Infection of Macrophages: Implications for Pathogenesis and Cure

    Directory of Open Access Journals (Sweden)

    Kiera Leigh Clayton

    2017-05-01

    Full Text Available Although CD4+ T cells represent the major reservoir of persistent HIV and SIV infection, accumulating evidence suggests that macrophages also contribute. However, investigations of the role of macrophages are often underrepresented at HIV pathogenesis and cure meetings. This was the impetus for a scientific workshop dedicated to this area of study, held in Cambridge, MA in January 2017. The workshop brought together experts in the fields of HIV/SIV immunology/virology, macrophage biology and immunology, and animal models of HIV/SIV infection to facilitate discussions regarding the role of macrophages as a physiologically relevant viral reservoir, and the implications of macrophage infection for HIV pathogenesis and cure strategies. An emerging consensus that infected macrophages likely persist in the setting of combination antiretroviral therapy, driving persistent inflammation and contributing to the viral reservoir, indicate the importance of addressing macrophages as well as CD4+ T cells with future therapeutic strategies.

  7. Monolithic growth of partly cured polydimethylsiloxane thin film layers

    DEFF Research Database (Denmark)

    Yu, Liyun; Skov, Anne Ladegaard

    2014-01-01

    at different curing times. The monolithic films are investigated by rheology, scanning electron microscope, mechanical testing, dielectric relaxation spectroscopy, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology, mechanical and dielectric properties, as well...... to enable interlayer crosslinking reactions either by application of an adhesion promoter or by ensuring that there are reactive, complementary sites available on the two surfaces. Polydimethylsiloxane (PDMS) is a widely used polymer for DEAPs. In this work, two-layered PDMS films are adhered together...... as thermal stabilities of the bilayer elastomer films are observed to change with the curing time of the monolayers before lamination. The objective of this work is to create adhesion of two layers without destroying the original viscoelastic properties of the PDMS films, and hence enable, for example...

  8. Epoxy-silicate nanocomposites: Cure monitoring and characterization

    International Nuclear Information System (INIS)

    Hussain, Farzana; Chen, Jihua; Hojjati, Mehdi

    2007-01-01

    Epoxy-clay nanocomposites were prepared with organically modified layered clay with varying clay contents (1-8 wt.%). Neat resin and nanocomposite were characterized using different techniques. At first, the effect of nanoclay concentration on the cure behaviour was investigated using an on-line dielectric cure monitoring technique. Differential scanning calorimetry (DSC) was used to verify the dielectric measurement results. Furthermore, mechanical and thermal properties were studied using tensile test and Dynamic Mechanical Analysis (DMA), respectively. Experimental results showed that properties of the epoxy were changed evidently because of the nanoclay loading. The tensile modulus of the nanocomposites increased by 47%, however, no improvement in tensile strength and glass transition temperature (T g ) was observed. Fracture surface of the tensile samples were analyzed by Scanning Electron Microscope (SEM). The nanocomposites structures were characterized with Wide Angle X-Ray Diffraction (WAXD) and Transmission Electron Microscopy (TEM), which revealed the intercalated morphology of clay layers in the epoxy resin systems

  9. Arnica Tincture Cures Cutaneous Leishmaniasis in Golden Hamsters

    Directory of Open Access Journals (Sweden)

    Sara M. Robledo

    2018-01-01

    Full Text Available In search for potential therapeutic alternatives to existing treatments for cutaneous Leishmaniasis, we have investigated the effect of Arnica tincture Ph. Eur. (a 70% hydroethanolic tincture prepared from flowerheads of Arnica montana L. on the lesions caused by infection with Leishmania braziliensis in a model with golden hamsters. The animals were treated topically with a daily single dose of the preparation for 28 days. Subsequently, the healing process was monitored by recording the lesion size in intervals of 15 days up to day 90. As a result, Arnica tincture fully cured three out of five hamsters while one animal showed an improvement and another one suffered from a relapse. This result was slightly better than that obtained with the positive control, meglumine antimonate, which cured two of five hamsters while the other three showed a relapse after 90 days. This result encourages us to further investigate the potential of Arnica tincture in the treatment of cutaneous Leishmaniasis.

  10. Some Durability Aspects of Ambient Cured Bottom Ash Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Saravanakumar R.

    2017-09-01

    Full Text Available The present study examines some durability aspects of ambient cured bottom ash geopolymer concrete (BA GPC due to accelerated corrosion, sorptivity, and water absorption. The bottom ash geopolymer concrete was prepared with sodium based alkaline activators under ambient curing temperatures. The sodium hydroxide used concentration was 8M. The performance of BA GPC was compared with conventional concrete. The test results indicate that BA GPC developes a strong passive layer against chloride ion diffusion and provides better protection against corrosion. Both the initial and final rates of water absorption of BA GPC were about two times less than those of conventional concrete. The BA GPC significantly enhanced performance over equivalent grade conventional concrete (CC.

  11. On the probability of cure for heavy-ion radiotherapy

    International Nuclear Information System (INIS)

    Hanin, Leonid; Zaider, Marco

    2014-01-01

    The probability of a cure in radiation therapy (RT)—viewed as the probability of eventual extinction of all cancer cells—is unobservable, and the only way to compute it is through modeling the dynamics of cancer cell population during and post-treatment. The conundrum at the heart of biophysical models aimed at such prospective calculations is the absence of information on the initial size of the subpopulation of clonogenic cancer cells (also called stem-like cancer cells), that largely determines the outcome of RT, both in an individual and population settings. Other relevant parameters (e.g. potential doubling time, cell loss factor and survival probability as a function of dose) are, at least in principle, amenable to empirical determination. In this article we demonstrate that, for heavy-ion RT, microdosimetric considerations (justifiably ignored in conventional RT) combined with an expression for the clone extinction probability obtained from a mechanistic model of radiation cell survival lead to useful upper bounds on the size of the pre-treatment population of clonogenic cancer cells as well as upper and lower bounds on the cure probability. The main practical impact of these limiting values is the ability to make predictions about the probability of a cure for a given population of patients treated to newer, still unexplored treatment modalities from the empirically determined probability of a cure for the same or similar population resulting from conventional low linear energy transfer (typically photon/electron) RT. We also propose that the current trend to deliver a lower total dose in a smaller number of fractions with larger-than-conventional doses per fraction has physical limits that must be understood before embarking on a particular treatment schedule. (paper)

  12. Curing characteristics of flowable and sculptable bulk-fill composites

    OpenAIRE

    Miletic, Vesna; Pongpruenska, Pong; De Munck, Jan; Brooks, Neil R; Van Meerbeek, Bart

    2016-01-01

    OBJECTIVES: The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites. MATERIALS AND METHODS: Six specimens per group, consisting of Tetric EvoCeram Bulk Fill ("TEC Bulk," Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement ("SDR," Dentsply), Xenius base ("Xenius," StickTech; commercialized as EverX Posterior, GC), Filtek Bul...

  13. Depth of Cure of New Flowable Composite Resins

    Science.gov (United States)

    2012-03-30

    we met. His encouragement and undiminished love for the past 20 years has been my motivation. This thesis is also dedicated to my four children ...assessed to be the most commonly used by dentists. Therefore, the depths of cure data from this study are pertinent to the practice of dentistry ...Continuing Education in Dentistry . Http://cde.dentalaegis.com Dai Q, Bertrand S. Wear resistance of Surefil SDR Flow posterior flowable base. JDR

  14. SENSORY CHARACTERISTICS OF NATIVE CHICKEN QUEEN PINEAPPLE-CURED HAM

    OpenAIRE

    Dr. Lilibeth A. Roxas; Nikko A. Roxas

    2015-01-01

    The potential of Native Chicken to be processed into palatable ham was conducted making use of Queen Pineapple (QP) crude extract as one of the curing ingredients. Primarily, the main goal is to develop a protocol in the manufacture of processed native chicken ham and determine the organoleptic quality of native chicken ham product. The age of the bird and maturity of the fruit were considered for the best organoleptic quality of chicken ham. In this study, the combine injectio...

  15. Epoxy Nanocomposites - Curing Rheokinetics, Wetting and Adhesion to Fibers

    International Nuclear Information System (INIS)

    Ilyin, S. O.; Kotomin, S. V.; Kulichikhin, V. G.

    2010-01-01

    Epoxy nanocomposites considered as challenging polymeric matrix for advanced reinforced plastics. Nanofillers change rheokinetics of epoxy resin curing, affect wetting and adhesion to aramid and carbon fibers. In all cases extreme dependence of adhesive strength vs filler content in the binder was observed. New experimental techniques were developed to study wettability and fiber-matrix adhesion interaction, using yarn penetration path length, aramid fiber knot pull-up test and electrical admittance of the fracture surface of CFRP.

  16. UV-LED Curing Efficiency of Wood Coatings

    Directory of Open Access Journals (Sweden)

    Véronic Landry

    2015-12-01

    Full Text Available Ultraviolet light emitting diodes (UV-LEDs have attracted great interest in recent years. They can be used to polymerize coatings, such as those used for prefinished wood flooring. In this project, two lamps were compared for their suitability to be used on a wood flooring finishing line: a UV-microwave and a UV-LED lamp. Low heat emission was found for the UV-LED lamp compared to the UV-microwave one. This study also reveals that the 4 W/cm2 UV-LED lamp used is not powerful enough to cure UV high solids acrylate coatings while satisfactory results can be obtained for UV water-based formulations. In fact, conversion percentages were found to be low for the high solids coatings, leaving the coatings tacky. Higher conversion percentages were obtained for the UV water-based formulations. As a result, mass loss, hardness, and scratch resistance found for the samples cured by UV-LED were closed to the ones found for the samples cured using the UV microwave lamp.

  17. The electron beam cure of epoxy paste adhesives

    International Nuclear Information System (INIS)

    Farmer, J.D.; Janke, C.J.; Lopata, V.J.

    1998-01-01

    Recently developed epoxy paste adhesives were electron beam cured and experimentally explored to determine their suitability for use in an aerospace-quality aircraft component. There were two major goals for this program. The first was to determine whether the electron beam-curable past adhesives were capable of meeting the requirements of the US Air Force T-38 supersonic jet trainer composite windshield frame. The T-38 windshield frame's arch is currently manufactured by bonding thin stainless steel plies using an aerospace-grade thermally-cured epoxy film adhesive. The second goal was to develop the lowest cost hand layup and debulk process that could be used to produce laminated steel plies with acceptable properties. The laminate properties examined to determine adhesive suitability include laminate mechanical and physical properties at room, adhesive tack, out-time capability, and the debulk requirements needed to achieve these properties. Eighteen past adhesives and four scrim cloths were experimentally examined using this criteria. One paste adhesive was found to have suitable characteristics in each of these categories and was later chosen for the manufacture of the T-38 windshield frame. This experimental study shows that by using low-cost debulk and layup processes, the electron beam-cured past adhesive mechanical and physical properties meet the specifications of the T-38 composite windshield frame

  18. Cure of Helicobacter pylori-associated ulcer disease through eradication.

    Science.gov (United States)

    Malfertheiner, P; Leodolter, A; Peitz, U

    2000-02-01

    The eradication of Helicobacter pylori (H. pylori) infection has led to a dramatic benefit for patients with gastroduodenal ulcer disease, as the majority of these patients receive a lifelong cure. Relapses after successful H. pylori cure may be caused by either recrudescence or reinfection, both rare events nowadays, or be attributed to non-steroidal anti-inflammatory drugs or aspirin intake. In certain geographical areas, H. pylori-negative relapses are proposed as a new, pathophysiological and not yet elucidated entity. The cure of H. pylori infection in uncomplicated duodenal ulcer diseases consists of 7 days of proton pump inhibitor (PPI) based triple therapy, containing two antibiotics from clarithromycin, amoxicillin and metronidazole. In gastric ulcer, it is recommended that the PPI is continued for a further 3 weeks as these ulcers have a prolonged healing time. Rescue therapies after failure need to take into consideration the resistance pattern of the micro-organism and are offered in the form of quadruple therapy or a high-dose PPI with amoxicillin.

  19. Alteration of histological gastritis after cure of Helicobacter pylori infection.

    Science.gov (United States)

    Hojo, M; Miwa, H; Ohkusa, T; Ohkura, R; Kurosawa, A; Sato, N

    2002-11-01

    It is still disputed whether gastric atrophy or intestinal metaplasia improves after the cure of Helicobacter pylori infection. To clarify the histological changes after the cure of H. pylori infection through a literature survey. Fifty-one selected reports from 1066 relevant articles were reviewed. The extracted data were pooled according to histological parameters of gastritis based on the (updated) Sydney system. Activity improved more rapidly than inflammation. Eleven of 25 reports described significant improvement of atrophy. Atrophy was not improved in one of four studies with a large sample size (> 100 samples) and in two of five studies with a long follow-up period (> 12 months), suggesting that disagreement between the studies was not totally due to sample size or follow-up period. Methodological flaws, such as patient selection, and statistical analysis based on the assumption that atrophy improves continuously and generally in all patients might be responsible for the inconsistent results. Four of 28 studies described significant improvement of intestinal metaplasia [corrected]. Activity and inflammation were improved after the cure of H. pylori infection. Atrophy did not improve generally among all patients, but improved in certain patients. Improvement of intestinal metaplasia was difficult to analyse due to methodological problems including statistical power.

  20. Cure electrocoagulation demonstration at Rocky Flats Environmental Technology Site

    International Nuclear Information System (INIS)

    Bridges, J.L.; Jones, J.; Ball, T.

    1996-01-01

    A demonstration of an innovative technology for remediating radionuclide contamination in water took place at the Rocky Flats Environmental Technology Site (RFETS) in Golden, Colorado, during the summer of 1995. The demonstration was part of the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) program and was conducted by EPA, the U.S. Department of Energy (DOE), and General Environmental Corporation (GEC). The SITE program encourages the development and demonstration of innovative treatment and monitoring technologies. The purpose of the demonstration was to evaluate the ability of GEC's innovative CURE technology to remove uranium, plutonium, and americium from water taken from the A and B solar evaporation ponds at RFETS. The CURE electrocoagulation process uses an anode and cathode in a patented geometry to remove contaminants, including radionuclides, from wastewater in a continuous flow process. Electrocoagulation has been recognized as a method of removing a variety of contaminants from wastewaters. With the CURE process, GEC has refined the technology and adapted it to hazardous waste cleanup. Bench scale treatability testing conducted in April 1995 indicated 99 percent removal efficiencies were possible for uranium, plutonium-239/240, and americium-241. During the field scale demonstration in August and September 1995, samples were collected from four demonstration runs at RFETS. A removal efficiency of approximately 50 percent was achieved for uranium and nearly 99 percent for plutonium and americium

  1. Self-curing concrete types; water retention and durability

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-09-01

    This study was carried out to compare among concretes without or with silica fume (SF along with chemical type of shrinkage reducing admixture, polyethylene-glycol (Ch, and leca as self-curing agents for water retention even at elevated temperature (50 °C and their durability. The cement content of 400 kg/m3, silica fume of 15% by weight of cement, polyethylene-glycol of 2% by weight of cement, pre-saturated lightweight aggregate (leca 15% by volume of sand and water with Ch/binder ratio of 0.4 were selected in this study. Some of the physical and mechanical properties were determined periodically up to 28 days in case of exposure to air curing in temperature of (25 °C and (50 °C while up to 6 months of exposure to 5% of carbon dioxide and wet/dry cycles in 8% of sodium chloride for durability study. The concrete mass loss and the volumetric water absorption were measured, to evaluate the water retention of the investigated concretes. Silica fume concrete either without or with Ch gave the best results under all curing regimes; significant water retention and good durability properties.

  2. Cure electrocoagulation demonstration at Rocky Flats Environmental Technology Site

    Energy Technology Data Exchange (ETDEWEB)

    Bridges, J.L.; Jones, J.; Ball, T. [PRC Environmental Management, Inc., Denver, CO (United States)] [and others

    1996-12-31

    A demonstration of an innovative technology for remediating radionuclide contamination in water took place at the Rocky Flats Environmental Technology Site (RFETS) in Golden, Colorado, during the summer of 1995. The demonstration was part of the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) program and was conducted by EPA, the U.S. Department of Energy (DOE), and General Environmental Corporation (GEC). The SITE program encourages the development and demonstration of innovative treatment and monitoring technologies. The purpose of the demonstration was to evaluate the ability of GEC`s innovative CURE technology to remove uranium, plutonium, and americium from water taken from the A and B solar evaporation ponds at RFETS. The CURE electrocoagulation process uses an anode and cathode in a patented geometry to remove contaminants, including radionuclides, from wastewater in a continuous flow process. Electrocoagulation has been recognized as a method of removing a variety of contaminants from wastewaters. With the CURE process, GEC has refined the technology and adapted it to hazardous waste cleanup. Bench scale treatability testing conducted in April 1995 indicated 99 percent removal efficiencies were possible for uranium, plutonium-239/240, and americium-241. During the field scale demonstration in August and September 1995, samples were collected from four demonstration runs at RFETS. A removal efficiency of approximately 50 percent was achieved for uranium and nearly 99 percent for plutonium and americium.

  3. 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.

  4. CURING AND MECHANICAL PROPERTIES OF CHLOROSULPHONATED POLYETHYLENE RUBBER BLEND

    Directory of Open Access Journals (Sweden)

    Jaroslava Budinski-Simendić

    2011-09-01

    Full Text Available In this paper, the curing and mechanical properties of two series of prepared blends, i.e., chlorosulphonated polyethylene (CSM/isobutylene-co-isoprene (IIR rubber blends and chlorosulphonated polyethylene (CSM/chlorinated isobutylene-co-isoprene (CIIR rubber blends were carried out. Blends were prepared using a two-roll mill at a temperature of 40-50 °C. The curing was assessed using a Monsanto oscillating disc rheometer R-100. The process of vulcanization accelerated sulfur of pure rubbers and their blends was carried out in an electrically heated laboratory hydraulic press under a pressure of about 4 MPa and 160 °C. The stress-strain experiments were performed using a tensile tester machine (Zwick 1425. Results indicate that the scorch time, ts2, and optimum cure time, tc90, increase with increasing CSM content in both blends. The value of modulus at 100 and 300% elongation and tensile strength increases with increasing CSM content, whereas elongation at break shows a decreasing trend. The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement and scanning electron microscopy studies of the rubber blends fractured surfaces

  5. UV curing of teak veneers for decorative panel

    International Nuclear Information System (INIS)

    Gatot Trimulyadi Rekso; Darsono

    1999-01-01

    The radiation curing of surface coating of teak veneers for decorative panels has been conducted by using ultra violet (UV) as radiation source. In this experiment teak wood veneer was use as a substrate. Epoxy acrylate (import product,) and unsaturated polyester (locally product) were used as coating materials after being added with difunctional monomer TPGDA, and photo-initiator darocur 1173 or irgacure 184. Irradiation was conducted using 80 watt/cm LTV source at conveyor speed of 3,0 m/min. Parameters observed were viscosity of coating materials, hardness, adhesion, appearance, abrasion and chemical resistance of cured films. In general the results showed that viscosity of the formulations based on epoxy acrylate and unsaturated polyester resin were effected by the storage. Film cured by LTV made of epoxy acrylate and unsaturated polyester on the teak veneer wood have the same adhesion and abrasion resistant properties but the hardness and chemical resistant of epoxy acrylate are better than unsaturated polyester. From the experiment result it can be concluded the unsaturated polyester (locally product) can be used as radiation curable material for coating teak veneer panels

  6. How far is cancer cured by radiation sensitization?

    International Nuclear Information System (INIS)

    Ando, Koichi; Sasaki, Takehito; Ikeda, Hiroshi

    1990-01-01

    Some types of cancer are not cured by radiation alone in view of histology, location, and size. In facing so-called radioresistant cancer, antineoplastic agents, hypoxic cell sensitizers, biological response modifiers, or hyperthermia are used in combination with radiation, with the aim of cancer cure. First of all, this chapter discusses the subject of 'what is tumor cure by radiation therapy'. Current conditions of the aforementioned combined modalities and the future perspectives are presented. The following subjects are covered: (1) tumor control - significance of the number of stem cells; (2) biological evaluation of chemo-radiotherapy with cisplatin; (3) clinical results and experience with combination of radiotherapy and radiosensitizers; (4) radiosensitization with hypoxic cell radiosensitizers - present status (5) hypoxic cell radiosensitizers - present status and problems from the viewpoint of clinical radiotherapy; (6) thermal radiosensitization in vitro and its implications for radiotherapy; (7) clinical assessment of thermoradiotherapy for breast cancer and cancer of the urinary bladder; (8) interactions of radiation and biological response modifiers in the treatment of malignant tumor; (9) improvement in the effects of radiation therapy with biological response modifiers. (N.K.)

  7. Occurrence of Metastudtite (Uranium Peroxide Dihydrate) at a FUSRAP Site

    International Nuclear Information System (INIS)

    Young, C.M.; Nelson, K.A.; Stevens, G.T.; Grassi, V.J.

    2006-01-01

    Uranium concentrations in groundwater in a localized area of a site exceed the USEPA Maximum Contaminant Level (MCL) by a factor of one thousand. Although the groundwater seepage velocity ranges up to 0.7 meters per day (m/day), data indicate that the uranium is not migrating in groundwater. We believe that the uranium is not mobile because of local geochemical conditions and the unstable nature of the uranium compound present at the site; uranium peroxide dihydrate (metastudtite). Metastudtite [UO 4 .2(H 2 O) or (U(O 2 )|O|(OH) 2 ).3H 2 O] has been identified at other sites as an alteration product in casks of spent nuclear fuel, but neither enriched nor depleted uranium were present at this site. Metastudtite was first identified as a natural mineral in 1983, although documented occurrences in the environment are uncommon. The U.S. Army Corps of Engineers (USACE) is conducting a remedial investigation at the DuPont Chambers Works in Deep water New Jersey under the Formerly Utilized Sites Remedial Action Program (FUSRAP) to evaluate radioactive contamination resulting from historical activities conducted in support of Manhattan Engineering District operations. From 1942 to 1947, Chambers Works converted uranium oxides to uranium tetrafluoride and uranium metal. More than half of the production at this facility resulted from the recovery process, where uranium-bearing dross and scrap were reacted with hydrogen peroxide to produce uranium peroxide dihydrate. The 280-hectare Chambers Works has produced some 600 products, including petrochemicals, aromatics, fluoro-chemicals, polymers, and elastomers. Contaminants resulting from these processes, including separate-phase petrochemicals, have also been detected within the boundaries of the FUSRAP investigation. USACE initiated remedial investigation field activities in 2002. The radionuclides of concern are natural uranium (U nat ) and its short-lived progeny. Areas of impacted soil generally correspond to the

  8. Plutonium(IV) peroxide formation in nitric medium and kinetics Pu(VI) reduction by hydrogen peroxide

    International Nuclear Information System (INIS)

    Maillard, C.; Adnet, J.M.

    2001-01-01

    Reduction of plutonium (VI) to Pu(IV) with hydrogen peroxide is a step in industrial processes used to purify plutonium nitrate solutions. This operation must be carefully controlled, in order to avoid any formation of the Pu(IV) peroxide green precipitate and to obtain exclusively Pu(IV). This led us to study the acidity and Pu and H 2 O 2 concentrations influences on the precipitate appearance and to perform a Pu(VI) reduction kinetic study on a wide range of acidities ([HNO 3 ]: 0.5 to 8 M), plutonium concentrations ([Pu(VI)]: 0.1 to 0.8 M) and [H 2 O 2 ]/[Pu(VI)] ratio (from 1 to 8). Thus, the domain of Pu(IV) peroxide formation and the reactional paths were established. With the exception of 0.5 M nitric acid medium, the kinetic curves show two distinct regims: the first one corresponds to an induction period where the Pu(VI) concentration doesn't change, the second corresponds to a linear decrease of Pu(VI). An increase of the temperature greatly accelerates the Pu(VI) reduction rate while [H 2 O 2 ]/[Pu(VI)] has almost no influence. The Pu(VI) total reduction time decreases when initial concentration of plutonium increases. By increasing nitric acid concentration from 0.5 M to 6 M, the total Pu(VI) reduction time decreases. This time increases when [HNO 3 ] varies from 6 M to 8 M. (orig.)

  9. 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)

  10. Monitoring cure of composite resins using frequency dependent electromagnetic sensing techniques

    Science.gov (United States)

    Kranbuehl, D. E.; Hoff, M. S.; Loos, A. C.; Freeman, W. T., Jr.; Eichinger, D. A.

    1988-01-01

    A nondestructive in situ measurement technique has been developed for monitoring and measuring the cure processing properties of composite resins. Frequency dependent electromagnetic sensors (FDEMS) were used to directly measure resin viscosity during cure. The effects of the cure cycle and resin aging on the viscosity during cure were investigated using the sensor. Viscosity measurements obtained using the sensor are compared with the viscosities calculated by the Loos-Springer cure process model. Good overall agreement was obtained except for the aged resin samples.

  11. Evaluation of the hydrogen peroxide and special colorant effects under irradiation by argon and diode laser on tooth-whitening in vitro

    International Nuclear Information System (INIS)

    Gaspar, Jose Antonio

    2003-01-01

    The aim of this study is to determine if there is any interaction between special colorant found on bleaching agents that have 35 % of hydrogen peroxide on its composition, and argon or diode laser. The first part of the study was to characterize the extrinsic stain obtained through a staining solution containing products present on the day by day diet of the general population. Thirty-two inferior human extracted incisors, free of caries and without filling material were selected for the study. The laser devices employed were Argon laser (AccuCure 3000 TM - Lasermed), wave length 488 nm, with a 200 mW/cm 2 for 30 seconds in continuos mode; and diode laser (L 808 Medical Laser - Lasering do Brasil), wave length 808 ± 10 nm, with 1,6 W/cm 2 for 30 seconds in continuos mode. The application mode done by a scanning movement over the buccal surface. The bleaching agents used were: Opalescence Extra (OE) - Ultradent Products USA, hydrogen peroxide 35%, gel with Carotene to convert light into heat; Pola Office (PO) - SDI - USA single doses of hydrogen peroxide; Whiteness HP (WHP) - FGM - Brasil, hydrogen peroxide 35%; Opus White (OW) - Sharplan - Israel, hydrogen peroxide 35%. The temperature rise measurement was performed with a thermocouple model 120-202-AJ, Fenwal, inserted into the pulpar chamber. The bleaching material was applied on the tooth surface with 2 mm thickness and then the irradiation was perform. The thirty two teeth were randomized in four groups, two for each laser device. The obtain data demonstrated a superior performance of the Argon laser on tooth whitening and also better results concerning the temperature rise. The alteration on tooth coloration was verified through digital spectrophotometer (Shade-Eye EX - Shofu) and quantitative analyses showed statistical differences among the groups. The bleaching results for Argon laser combined with OE and WHP were superior for the other groups. The mean variation of the temperature rise obtained Argon

  12. Kinetics and mechanism of the furan peroxide formation in the reaction of furfural with hydrogen peroxide in the presence and absence of sodium molybdate

    International Nuclear Information System (INIS)

    Grunskaya, E.P.; Badovskaya, L.A.; Kaklyugina, T.Ya.; Poskonin, V.V.

    2000-01-01

    Kinetics of the initial stage of the reaction of furfural with hydrogen peroxide are studied in the presence of Na 2 MoO 4 in water and without catalytic additions in n-butanol. Organic peroxide having in its disposal Mo(6), which is the only product on the initial stage of the reaction, is formed since the first minutes of oxidation of furfural by hydrogen peroxide with the presence of Na 2 MoO 4 . The mechanisms of conversion of furfural in the Na 2 MoO 4 - H 2 O system and its oxidation by peroxide without sodium molybdate are discussed. Schemes of formation of furfural complexes based on the results of kinetic studies are suggested. Comparison of obtained data demonstrates that presence of the sodium molybdates in the reaction medium trends to change of reaction procedure in the hydrogen peroxide [ru

  13. Effect of light-curing units, post-cured time and shade of resin cement on knoop hardness.

    Science.gov (United States)

    Reges, Rogério Vieira; Costa, Ana Rosa; Correr, Américo Bortolazzo; Piva, Evandro; Puppin-Rontani, Regina Maria; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

    2009-01-01

    The aim of this study was to evaluate the Knoop hardness after 15 min and 24 h of different shades of a dual-cured resin-based cement after indirect photoactivation (ceramic restoration) with 2 light-curing units (LCUs). The resin cement Variolink II (Ivoclar Vivadent) shade XL, A2, A3 and opaque were mixed with the catalyst paste and inserted into a black Teflon mold (5 mm diameter x 1 mm high). A transparent strip was placed over the mold and a ceramic disc (Duceram Plus, shade A3) was positioned over the resin cement. Light-activation was performed through the ceramic for 40 s using quartz-tungsten-halogen (QTH) (XL 2500; 3M ESPE) or light-emitting diode (LED) (Ultrablue Is, DMC) LCUs with power density of 615 and 610 mW/cm(2), respectively. The Koop hardness was measured using a microhardness tester HMV 2 (Shimadzu) after 15 min or 24 h. Four indentations were made in each specimen. Data were subjected to ANOVA and Tukey's test (alpha=0.05). The QTH LCU provided significantly higher (pcement showed lower Knoop hardness than the other shades for both LCUs and post-cure times.

  14. Efficiency of Sodium Polyacrylate to Improve Durability of Concrete under Adverse Curing Condition

    Directory of Open Access Journals (Sweden)

    Tanvir Manzur

    2015-01-01

    Full Text Available The conventional external curing process requires supply of large amount of water in addition to mixing water as well as strict quality control protocol. However, in a developing country like Bangladesh, many local contractors do not have awareness and required knowledge on importance of curing which often results in weaker concrete with durability issues. Moreover, at times it is difficult to maintain proper external curing process due to nonavailability of water and skilled laborer. Internal curing can be adopted under such scenario since this method is simple and less quality intensive. Usually, naturally occurring porous light weight aggregates (LWA are used as internal curing agent. However, naturally occurring LWA are not available in many countries like Bangladesh. Under these circumstances, Super Absorbent Polymer (SAP can be utilized as an alternative internal curing agent. In this study, sodium polyacrylate (SP as SAP has been used to produce internally cured concrete. Desorption isotherm of SP has been developed to investigate its effectiveness as internal curing agent. Test results showed that internally cured concrete with SP performed better in terms of both strength and durability as compared to control samples when subjected to adverse curing conditions where supply of additional water for external curing was absent.

  15. Warpage of QFN Package in Post Mold Cure Process of integrated circuit packaging

    Science.gov (United States)

    Sriwithoon, Nattha; Ugsornrat, Kessararat; Srisuwitthanon, Warayoot; Thonglor, Panakamon

    2017-09-01

    This research studied about warpage of QFN package in post mold cure process of integrated circuit (IC) packages using pre-plated (PPF) leadframe. For IC package, epoxy molding compound (EMC) are molded by cross linking of compound stiffness but incomplete crosslinked network and leading the fully cured thermoset by post mold cure (PMC) process. The cure temperature of PMC can change microstructure of EMC in term of stress inside the package and effect to warpage of the package due to coefficient of thermal expansion (CTE) between EMC and leadframe. In experiment, cure temperatures were varied to check the effect of internal stress due to different cure temperature after completed post mold cure for TDFN 2×3 8L. The cure temperature were varied with 180 °C, 170 °C, 160 °C, and 150°C with cure time 4 and 6 hours, respectively. For analysis, the TDFN 2×3 8L packages were analyzed the warpage by thickness gauge and scanning acoustic microscope (SAM) after take the test samples out from the oven cure. The results confirmed that effect of different CTE between EMC and leadframe due to different cure temperature resulting to warpage of the TDFN 2×3 8L packages.

  16. 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.

  17. Pulp chamber temperature rise during curing of resin-based composites with different light-curing units.

    Science.gov (United States)

    Durey, Kathryn; Santini, Ario; Miletic, Vesna

    2008-01-01

    The purpose of the present study was to measure the intrapulpal temperature rise occurring during polymerisation of different shades of resin-based composites (RBCs), and two light-emitting diode (LED) units. Seventy non-carious permanent molars, that had been extracted for orthodontic purposes and stored in 2% thymol for not more than four months, were selected. Patient age range was 11-18 years. Standard cavity preparation with standardised remaining dentine thickness and placement of thermocouples (TCs) was prepared using a novel split-tooth technique. Cavities were filled with one of two shades of RBC (A2 and C4, Filtek Z250, 3M ESPE, Seefeld, Germany), and cured with two LED high-intensity units (Elipar Freelight2, 3M ESPE, Seefeld, Germany; Bluephase, Ivoclar Vivadent, Schaan, Liechtenstein) and a conventional halogen light-curing unit (LCU) (Prismetics Lite 2, Dentsply, Weybridge, Surrey, UK) as a control. Pulp temperature rises during bonding [A2 results: H;2.67/0.48:E;5.24/1.32;B;5.99/1.61] were always greater than during RBC curing [A2 results: 2.44/0.63;E3.34/0.70;B3.38/0.60], and these were significant for both LED lights but not for the halogen control, irrespective of shade (Mann-Whitney test: 95% confidence limits). Temperature rises were at times in excess of the values normally quoted as causing irreversible pulp damage. Pulp temperature rises during bonding were higher with the LED lights than with the halogen control. There was no significant difference in temperature rise between the two LED lights when bonding but there was a significant difference between the two LED lights and the halogen control LCUs (Kruskal-Wallis Test: 95% confidence limits). The results support the view that there is a potential risk for heat-induced pulpal injury when light-curing RBCs. The risk is greater during bonding and with high energy, as compared to low-energy output systems. As the extent of tolerable thermal trauma by the pulp tissues is unknown, care and

  18. Do blood contamination and haemostatic agents affect microtensile bond strength of dual cured resin cement to dentin?

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    Kerem KiLiC

    2013-01-01

    Full Text Available Objective The purpose of this study was to evaluate the effects of blood contamination and haemostatic agents such as Ankaferd Blood Stopper (ABS and hydrogen peroxide (H2O2 on the microtensile bond strength between dual cured resin cement-dentin interface. Material and Methods Twelve pressed lithium disilicate glass ceramics were luted to flat occlusal dentin surfaces with Panavia F under the following conditions: Control Group: no contamination, Group Blood: blood contamination, Group ABS: ABS contamination Group H2O2: H2O2 contamination. The specimens were sectioned to the beams and microtensile testing was carried out. Failure modes were classified under stereomicroscope. Two specimens were randomly selected from each group, and SEM analyses were performed. Results There were significant differences in microtensile bond strengths (µTBS between the control and blood-contaminated groups (p0.05. Conclusions Contamination by blood of dentin surface prior to bonding reduced the bond strength between resin cement and the dentin. Ankaferd Blood Stoper and H2O2 could be used safely as blood stopping agents during cementation of all-ceramics to dentin to prevent bond failure due to blood contamination.

  19. Biochemical, Oxidative, and Lipolytic Changes during Vacuum-Packed Storage of Dry-Cured Loin: Effect of Chestnuts Intake by Celta Pigs

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    María Gómez

    2018-01-01

    Full Text Available The effect of the inclusion of chestnuts in the finishing diet of Celta pig breed on the characteristics of dry-cured loin, a traditional Spanish dry-cured meat product, after the manufacturing process and the vacuum-packed storage was studied. In general, no significant differences between the diets (chestnut, mixed, and concentrate diet were obtained for physicochemical (moisture, intramuscular fat, and titratable acidity and lipolytic parameters. Lower pH and higher values for oxidation parameters (peroxide and TBA values were obtained in loins from pigs fed with chestnuts. However, no differences were found for fatty acids from the different lipid fractions when diets were compared, with the exception of some minor fatty acids. Free fatty acids represented over 2.7% of the fat in the final product. The distinction between diets was procured when a discriminant canonical analysis was performed for fatty acid contents. After vacuum-packed storage, only a slight evolution of the studied parameters was obtained.

  20. Evaluation of enamel by scanning electron microscopy green LED associated to hydrogen peroxide 35% for dental bleaching

    Science.gov (United States)

    Monteiro, Juliana S. C.; de Oliveira, Susana C. P. S.; Zanin, Fátima A. A.; Santos, Gustavo M. P.; Sampaio, Fernando J. P.; Gomes Júnior, Rafael Araújo; Gesteira, Maria F. M.; Vannier-Santos, Marcos A.; Pinheiro, Antônio Luiz B.

    2014-02-01

    Dental bleaching is a frequently requested procedure in clinical dental practice. The literature is contradictory regarding the effects of bleaching agents on both morphology and demineralization of enamel after bleaching. The aim of this study was to analyze by SEM the effect of 35% neutral hydrogen peroxide cured by green LED. Buccal surfaces of 15 pre-molars were sectioned and marked with a central groove to allow experimental and control groups on the same specimen. For SEM, 75 electron micrographs were evaluated by tree observers at 43X, 220X and 1000X. Quantitative analysis for the determination of the surface elemental composition of the samples through X-ray microanalysis by SEM was also performed. The protocol tested neither showed significant changes in mineral composition of the samples nor to dental enamel structure when compared to controls. SEM analysis allowed inferring that there were marked morphological differences between the enamel samples highlighting the need for the use of the same tooth in comparative morphological studies. The tested protocol did not cause morphological damage the enamel surface when compared to their respective controls.