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Sample records for peroxide cured polypropylene-ethylene

  1. In situ reactive compatibilization of polypropylene/ethylene-propylene-diene monomer thermoplastic vulcanizate by zinc dimethacrylate via peroxide-induced dynamic vulcanization.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Liang, Xingquan; Cao, Liming

    2013-09-12

    This work demonstrates an approach of in situ reactive compatibilization between polypropylene (PP) and ethylene-propylene-diene monomer (EPDM) by using zinc dimethacrylate (ZDMA) as a compatibilizer and, simultaneously, as a very strong reinforcing agent. With the incorporation of 7phr ZDMA in the PP/EPDM (30/70, w/w) thermoplastic vulcanizate (TPV), the tensile strength, tear strength, elongation at break, and hardness of PP/EPDM/ZDMA TPV were increased from 5.3 MPa, 31.3 kN/m, 222%, and 78 up to 11.2 MPa, 64.2 kN/m, 396%, and 83, respectively. This tremendous reinforcing as well as the compatibilization effect of the ZDMA was understood by polymerization of ZDMA and ZDMA reacted with EPDM and PP during peroxide-induced dynamic vulcanization. A peculiar phase structure that rubber particles were surrounded and "bonded" by a thick transition zone that contained numerous of nanoparticles with dimensions of about 20-30 nm was observed from transmission electron microscopy. Scanning electron microscopy results confirmed that incorporation of ZDMA reduced the size of the cross-linked EPDM particles. Moreover, we found that the compatibilized TPV showed a higher tan δ peak temperature for EPDM phase and a lower tan δ peak temperature for PP phase. The suggested method for in situ reactive compatibilization of PP and EPDM offers routes to the design of new TPV-based technical products for diversified applications. PMID:23981036

  2. Morphology study of peroxide-induced dynamically vulcanized polypropylene/ethylene-propylene-diene monomer/zinc dimethacrylate blends during tensile deformation.

    PubMed

    Chen, Yukun; Xu, Chuanhui; Cao, Liming; Wang, Yanpeng; Fang, Liming

    2013-06-27

    Polypropylene (PP)/ethylene-propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blend (EPDM/PP ratio of 30/70) with remarkable extensibility was successfully prepared via peroxide dynamic vulcanization. The uniaxial tensile properties, crystallization behavior, structure, and morphology during stretching were investigated. The tensile process study showed that the PP/EPDM/ZDMA blend exhibited the rubbery-like behavior with an elongation beyond 600%. The ZDMA graft-product domain increased the compatibility and interfacial adhesion between rubber and PP phases, while it reduced the crystallinity of the PP phase. On the basis of TEM and SEM analyses, we found that the cross-linked rubber particles could be elongated and oriented along the tensile direction, whereas the ZDMA graft-product domain "encapsulated" rubber phase together, acting as a "bridge" between elongated rubber phases and the PP phase during uniaxial stretching. The stress could be effectively transferred from the PP phase to the numerous elongated rubber phases due to the excellent compatibility and interfacial adhesion between rubber and PP phases, resulting in the rubbery-like behavior. PMID:23742700

  3. Chemical Origins of Permanent Set in a Peroxide Cured Filled Silicone Elastomer - Tensile and 1H NMR Analysis

    SciTech Connect

    Chinn, S; Deteresa, S; Shields, A; Sawvel, A; Balazs, B; Maxwell, R S

    2004-10-29

    The aging of a commercial filled siloxane polymeric composite in states of high stress and Co-60 {gamma}-radiation exposure has been studied. DC-745 is a commercially available silicone elastomer consisting of dimethyl, methyl-phenyl, and vinyl-methyl siloxane monomers crosslinked with a peroxide vinyl specific curing agent. It is filled with {approx}30 wt.% mixture of high and low surface area silicas. This filled material is shown to be subject to permanent set if exposed to radiation while under tensile stress. Tensile modulus measurements show that the material gets marginally softer with combined radiation exposure and tensile strain as compared to material exposed to radiation without tensile strain. In addition, the segmental dynamics as measured by both uniaxial NMR relaxometry and Multiple Quantum NMR methods indicate that the material is undergoes radiatively-induced crosslinking in the absence of tensile strain and a combination of crosslinking and strain dependent increase in dynamic order parameter for the network chains. The MQ-NMR also suggests a small change in the number of polymer chains associated with the silica filler surface. Comparison of the prediction of the relative change in crosslink density from the NMR data as well as solvent swelling data and from that predicted from the Tobolsky model suggest that degradation leads to a deviation from Gaussian chain statistics and the formation of increased numbers of elastically ineffective network chains.

  4. Energy curable compositions having improved cure speeds

    DOEpatents

    Halm, L.W.

    1993-05-18

    The composition and method provide improved physical properties and cure speed of polyurethane precursors, with or without free radical polymerizable monomers or oligomers present, by use of a two component catalyst system. The resin blend can be activated with a latent organometallic catalyst combined with an organic peroxide which can be a hydroperoxide or an acyl peroxide to decrease the cure time while increasing the break energy and tangent modulus of the system.

  5. Energy curable compositions having improved cure speeds

    DOEpatents

    Halm, Leo W.

    1993-01-01

    A composition and method provide improved physical properties and cure speed of polyurethane precursors, with or without free radical polymerizable monomers or oligomers present, by use of a two component catalyst system. The resin blend can be activated with a latent organometallic catalyst combined with an organic peroxide which can be a hydroperoxide or an acyl peroxide to decrease the cure time while increasing the break energy and tangent modulus of the system.

  6. Cure SMA

    MedlinePlus

    ... real progress toward a treatment and a cure. Latest News August 29, 2016 2016 SMA Researcher Meeting ... Fundraisers Connect with Us Sign up for the latest SMA information Let us help you connect to ...

  7. Dynamically cured thermoplastic olefin polymers

    SciTech Connect

    Hazelton, D.R.; Puydak, R.C.; Booth, D.A.

    1986-08-19

    A thermoplastic composition is described comprising a polyolefin resin, a first rubber component selected from the group consisting of polyisobutylene, and ethylene propylene copolymer (EPM) and EPDM and a second rubber component selected from the group consisting of halogenated butyl rubber and polychoroprene, the second rubber component being cured utilizing a curative other than a peroxide, which is a vulcanizing agent for the second rubber but not for the first rubber, the second rubber being cured to a fully vulcanized state by dynamic vulcanization in the presence of the polyolefin resin and first rubber compound.

  8. Defining cure.

    PubMed

    Hilton, Paul; Robinson, Dudley

    2011-06-01

    This paper is a summary of the presentations made as Proposal 2-"Defining cure" to the 2nd Annual meeting of the ICI-Research Society, in Bristol, 16th June 2010. It reviews definitions of 'cure' and 'outcome', and considers the impact that varying definition may have on prevalence studies and cure rates. The difference between subjective and objective outcomes is considered, and the significance that these different outcomes may have for different stakeholders (e.g. clinicians, patients, carers, industry etc.) is discussed. The development of patient reported outcome measures and patient defined goals is reviewed, and consideration given to the use of composite end-points. A series of proposals are made by authors and discussants as to how currently validated outcomes should be applied, and where our future research activity in this area might be directed. PMID:21661023

  9. Hydrogen peroxide poisoning

    MedlinePlus

    ... peroxide is used in these products: Hydrogen peroxide Hair bleach Some contact lens cleaners Note: Household hydrogen peroxide ... it contains 97% water and 3% hydrogen peroxide. Hair bleaches are stronger. They usually have a concentration of ...

  10. Influence of curing agent on fibrosis around silicone implants.

    PubMed

    Joseph, Josna; Mohanty, Mira

    2013-01-01

    Severe capsular contracture around silicone expander breast implants leading to pain and failure is a major clinical problem. Even though earlier studies have implicated the immunogenicity of silicone, the role of physical and chemical properties of the silicone material in excessive collagen deposition and fibrosis has been less addressed. The present study investigates whether there is any correlation between the type of curing systems i.e. addition and free radical curing and the fibrosis around silicone elastomer. The experiment carried out uses commercially available silicone ventriculo-peritoneal shunt material elastomer cured by platinum and the results are compared with results obtained in a similar study carried out by the authors using commercially available silicone tissue expander material cured by peroxide. Ultra-high molecular weight poly-ethylene (UHMWPE), the standard reference for biocompatibility evaluation, was used as the control material. The materials were implanted in rat skeletal muscle for 30 and 90 days. Inflammatory cells, myofibroblasts, cytokines, and collagen deposition at the material-tissue interface were identified by haematoxylin-eosin and Masson's Trichrome stains and semi-quantitated based on immunohistochemical studies. Results indicate that even though the cellular response in the initial phase of wound healing was similar in both platinum and peroxide-cured materials, the collagen deposition in the proliferative phase was more around peroxide-cured material in comparison to the platinum-cured silicone elastomer. There is a need to look into the molecular mechanisms of this interaction and the possibility of using curing systems other than free radical peroxide in the manufacture of silicone elastomer expanders for breast prosthesis. PMID:23683043

  11. Electron beam curing of EPDM

    SciTech Connect

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

    1991-11-01

    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.

  12. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  13. Radiation curing of epoxies

    NASA Astrophysics Data System (ADS)

    Dickson, Lawrence W.; Singh, Ajit

    The literature on radiation polymerization of epoxy compounds has been reviewed to assess the potential use of radiation for curing these industrially important monomers. Chemical curing of epoxies may proceed by either cationic or anionic mechanisms depending on the nature of the curing agent, but most epoxies polymerize by cationic mechanisms under the influence of high-energy radiation. Radiation-induced cationic polymerization of epoxy compounds is inhibited by trace quantities of water because of proton transfer from the chain-propagating epoxy cation to water. Several different methods with potential for obtaining high molecular weight polymers by curing epoxies with high-energy radiation have been studied. Polymeric products with epoxy-like properties have been produced by radiation curing of epoxy oligomers with terminal acrylate groups and mixtures of epoxies with vinyl monomers. Both of these types of resin have good potential for industrial-scale curing by radiation treatment.

  14. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  15. A cure for dyslexia?

    PubMed

    2007-02-01

    A company is promoting behavioral exercises as a cure for dyslexia. Scientists worry that evaluation of the program is compromised by design flaws and conflicts of interest and that responses to critics restrict academic freedom. PMID:17259957

  16. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  17. On copper peroxide

    NASA Technical Reports Server (NTRS)

    Moser, L.

    1988-01-01

    The action of hydrogen superoxide on copper salts in alcoholic solutions is studied. The action of hydrogen peroxide on copper hydroxide in alcoholic suspensions, and the action of ethereal hydrogen peroxide on copper hydroxide are discussed. It is concluded that using the procedure proposed excludes almost entirely the harmful effect of hydrolysis.

  18. Benzoyl Peroxide Topical

    MedlinePlus

    Benzoyl peroxide comes in cleansing liquid or bar, lotion, cream, and gel for use on the skin. Benzoyl peroxide usually is used one or two ... the package or on your prescription label.The cleansing liquid and bar are used to wash the ...

  19. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  20. Curing Metastatic Breast Cancer.

    PubMed

    Sledge, George W

    2016-01-01

    Metastatic breast cancer is generally considered incurable, and this colors doctor-patient interactions for patients with metastatic disease. Although true for most patients, there appear to be important exceptions, instances where long-term disease-free survival occurs. Although these instances are few in number, they suggest the possibility of cure. How will we move toward cure for a much larger population of patients with metastatic disease? This article outlines a potential research agenda that might move us toward that distant goal. PMID:26759458

  1. Curing Children's Cancer

    MedlinePlus

    ... ALL is a cancer of the white blood cells, which fight infection. It is the most common cancer in children, representing 23 percent of all cancers among those 15 or younger. Forty years ago, ALL was incurable. Today, in the United States, its cure rate is a major success story—as many ...

  2. Hydrogen peroxide poisoning.

    PubMed

    Watt, Barbara E; Proudfoot, Alex T; Vale, J Allister

    2004-01-01

    Hydrogen peroxide is an oxidising agent that is used in a number of household products, including general-purpose disinfectants, chlorine-free bleaches, fabric stain removers, contact lens disinfectants and hair dyes, and it is a component of some tooth whitening products. In industry, the principal use of hydrogen peroxide is as a bleaching agent in the manufacture of paper and pulp. Hydrogen peroxide has been employed medicinally for wound irrigation and for the sterilisation of ophthalmic and endoscopic instruments. Hydrogen peroxide causes toxicity via three main mechanisms: corrosive damage, oxygen gas formation and lipid peroxidation. Concentrated hydrogen peroxide is caustic and exposure may result in local tissue damage. Ingestion of concentrated (>35%) hydrogen peroxide can also result in the generation of substantial volumes of oxygen. Where the amount of oxygen evolved exceeds its maximum solubility in blood, venous or arterial gas embolism may occur. The mechanism of CNS damage is thought to be arterial gas embolisation with subsequent brain infarction. Rapid generation of oxygen in closed body cavities can also cause mechanical distension and there is potential for the rupture of the hollow viscus secondary to oxygen liberation. In addition, intravascular foaming following absorption can seriously impede right ventricular output and produce complete loss of cardiac output. Hydrogen peroxide can also exert a direct cytotoxic effect via lipid peroxidation. Ingestion of hydrogen peroxide may cause irritation of the gastrointestinal tract with nausea, vomiting, haematemesis and foaming at the mouth; the foam may obstruct the respiratory tract or result in pulmonary aspiration. Painful gastric distension and belching may be caused by the liberation of large volumes of oxygen in the stomach. Blistering of the mucosae and oropharyngeal burns are common following ingestion of concentrated solutions, and laryngospasm and haemorrhagic gastritis have been

  3. Process for curing bismaleimide resins

    NASA Technical Reports Server (NTRS)

    Parker, John A. (Inventor); OTHY S.imides alone. (Inventor)

    1986-01-01

    This invention relates to vinyl pyridine group containing compounds and oligomers, their advantageous copolymerization with bismaleimide resins, and the formation of reinforced composites based on these copolymers. When vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are admixed with bismaleimides and cured to form copolymers the cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone.

  4. New addition curing polyimides

    NASA Technical Reports Server (NTRS)

    Frimer, Aryeh A.; Cavano, Paul

    1991-01-01

    In an attempt to improve the thermal-oxidative stability (TOS) of PMR-type polymers, the use of 1,4-phenylenebis (phenylmaleic anhydride) PPMA, was evaluated. Two series of nadic end-capped addition curing polyimides were prepared by imidizing PPMA with either 4,4'-methylene dianiline or p-phenylenediamine. The first resulted in improved solubility and increased resin flow while the latter yielded a compression molded neat resin sample with a T(sub g) of 408 C, close to 70 C higher than PME-15. The performance of these materials in long term weight loss studies was below that of PMR-15, independent of post-cure conditions. These results can be rationalized in terms of the thermal lability of the pendant phenyl groups and the incomplete imidization of the sterically congested PPMA. The preparation of model compounds as well as future research directions are discussed.

  5. Relaxed Poisson cure rate models.

    PubMed

    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. PMID:26686485

  6. The Peroxide Pathway

    NASA Technical Reports Server (NTRS)

    McNeal, Curtis I., Jr.; Anderson, William

    1999-01-01

    NASA's current focus on technology roadmaps as a tool for guiding investment decisions leads naturally to a discussion of NASA's roadmap for peroxide propulsion system development. NASA's new Second Generation Space Transportation System roadmap calls for an integrated Reusable Upper-Stage (RUS) engine technology demonstration in the FY03/FY04 time period. Preceding this integrated demonstration are several years of component developments and subsystem technology demonstrations. NASA and the Air Force took the first steps at developing focused upper stage technologies with the initiation of the Upper Stage Flight Experiment with Orbital Sciences in December 1997. A review of this program's peroxide propulsion development is a useful first step in establishing the peroxide propulsion pathway that could lead to a RUS demonstration in 2004.

  7. Destruction of peroxide explosives.

    PubMed

    Oxley, Jimmie C; Smith, James L; Huang, Jiaorong; Luo, Wei

    2009-09-01

    Chemicals containing multiple peroxide functionalities, such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), or hexamethylene triperoxide diamine (HMTD), can be explosive. They are impractical and are not used by legitimate military groups because they are shock and heat sensitive compared to military explosives. They are attractive to terrorists because synthesis is straightforward, requiring only a few easily obtained ingredients. Physical removal of these synthesis products is highly hazardous. This paper discusses methods to degrade peroxide explosives chemically, at room temperature. A number of mixtures containing metals (e.g., zinc, copper) and metal salts (e.g., zinc sulfate, copper chloride) were found effective, some capable of destroying TATP solutions in a few hours. Strong acids proved useful against solid peroxide materials; however, on a 1 g scale, addition of concentrated sulfuric acid caused TATP to detonate. Thus, this technique should only be used to destroy small-laboratory quantities. PMID:19737243

  8. Hydrogen peroxide catalytic decomposition

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2010-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

  9. The Lourdes Medical Cures Revisited†

    PubMed Central

    François, Bernard; Sternberg, Esther M.; Fee, Elizabeth

    2014-01-01

    This article examines the cures recorded in Lourdes, France, between 1858, the year of the Visions, and 1976, the date of the last certified cure of the twentieth century. Initially, the records of cures were crude or nonexistent, and allegations of cures were accepted without question. A Medical Bureau was established in 1883 to examine and certify the cures, and the medical methodology improved steadily in the subsequent years. We discuss the clinical criteria of the cures and the reliability of medical records. Some 1,200 cures were said to have been observed between 1858 and 1889, and about one hundred more each year during the “Golden Age” of Lourdes, 1890–1914. We studied 411 patients cured in 1909–14 and thoroughly reviewed the twenty-five cures acknowledged between 1947 and 1976. No cure has been certified from 1976 through 2006. The Lourdes phenomenon, extraordinary in many respects, still awaits scientific explanation. Lourdes concerns science as well as religion. PMID:22843835

  10. Electrochemical Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  11. Comparative static curing versus dynamic curing on tablet coating structures.

    PubMed

    Gendre, Claire; Genty, Muriel; Fayard, Barbara; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

    2013-09-10

    Curing is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24h of static curing and 4h of dynamic curing, both performed at 60°C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions. PMID:23792043

  12. Modeling HIV Cure

    NASA Astrophysics Data System (ADS)

    Perelson, Alan; Conway, Jessica; Cao, Youfang

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of post-treatment control (PTC) or ``functional cure'' of HIV-infection. Some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection such that the amount of virus in the circulation is maintained undetectable by clinical assays for years. The model explains PTC occurring in some patients by having a parameter regime in which the model exhibits bistability, with both a low and high steady state viral load being stable. The model makes a number of predictions about how to attain the low PTC steady state. Bistability in this model depends upon the immune response becoming exhausted when over stimulated. I will also present a generalization of the model in which immunotherapy can be used to reverse immune exhaustion and compare model predictions with experiments in SIV infected macaques given immunotherapy and then taken off of antiretroviral therapy. Lastly, if time permits, I will discuss one of the hurdles to true HIV eradication, latently infected cells, and present clinical trial data and a new model addressing pharmacological means of flushing out the latent reservoir. Supported by NIH Grants AI028433 and OD011095.

  13. Dielectric cure monitoring: Preliminary studies

    NASA Technical Reports Server (NTRS)

    Goldberg, B. E.; Semmel, M. L.

    1984-01-01

    Preliminary studies have been conducted on two types of dielectric cure monitoring systems employing both epoxy resins and phenolic composites. An Audrey System was used for 23 cure monitoring runs with very limited success. Nine complete cure monitoring runs have been investigated using a Micromet System. Two additional measurements were performed to investigate the Micromet's sensitivity to water absorption in a post-cure carbon-phenolic material. While further work is needed to determine data significance, the Micromet system appears to show promise as a feedback control device during processing.

  14. Delayed cure bismaleimide resins

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1984-08-07

    Polybismaleimides prepared by delayed curing of bis-imides having the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, Cl or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the --(CH.sub.2).sub.n -- group, optionally, is substituted by 1-3 methyl groups or by fluorine.

  15. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  16. Ambient curing fire resistant foams

    NASA Technical Reports Server (NTRS)

    Hamermesh, C. L.; Hogenson, P. A.; Tung, C. Y.; Sawko, P. M.; Riccitiello, S. R.

    1979-01-01

    The feasibility of development of an ambient curing foam is described. The thermal stability and flame spread index of the foams were found to be comparable to those of the high-temperature cured polyimide foams by Monsanto two-foot tunnel test and NASA T-3 Fire test. Adaptation of the material to spray in place applications is described

  17. Lithium peroxide primary element

    SciTech Connect

    Winsel, A.

    1982-05-04

    In a galvanic primary element of the system Li/H/sub 2/O/sub 2/, the aqueous cathode depolarizer H/sub 2/O/sub 2/ is fixated as a polyurethane gel. It can thereby be controlled and caused to react with the anode metal in accordance with the current drain requirements. This is accomplished using a ram to press the gel toward a conductor which covers the lithium anode, which may take the form of a metal grid and/or a gas diffusion electrode. The oxygen which forms in the working layer through catalytic decomposition of hydrogen peroxide creates a gas bubble when the current is interrupted or the ram is stopped, thereby interrupting the further supply of hydrogen peroxide to the catalyst.

  18. Protein oxidation and peroxidation.

    PubMed

    Davies, Michael J

    2016-04-01

    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 and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  19. Protein oxidation and peroxidation

    PubMed Central

    Davies, Michael J.

    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 and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  20. Towards a 'cure' for IBD.

    PubMed

    Fiocchi, Claudio

    2012-01-01

    To discuss a cure for IBD, one should first define the concept 'a cure'. If it is intended as the general restoration of health, this is already possible, as many current therapies do a good job in inducing long periods of remission in Crohn's disease, and colectomy can technically cure ulcerative colitis. If it is more strictly defined as the complete and permanent elimination of the cause, predisposing and permissive factors, reinstatement of normal microbial ecology and restoration of mucosal immune homeostasis, then a cure for IBD is out of reach, at least for now. Regardless of the definition, major strides have been made in attempting to cure IBD by addressing the key components of its pathogenesis: the environment (exposome), the genetic makeup (genome), the gut microbiota (microbiome) and the immune system (immunome). However, the isolated modulation of each component is insufficient to provide a cure, and different requirements may be needed depending on the stage of the disease and each patient subset. To achieve a cure, one key approach is currently missing: the integration of knowledge from all the pathogenic components. We continue to learn more and more about each component using traditional 'canonical' systems, which allow the accumulation of data without taking into consideration the other components. We are still not studying the 'omes' of IBD, we should be using 'omics' technologies that can generate a more global vision of IBD pathogenesis on which to base novel, multiple pathway-integrated therapies. PMID:22796811

  1. Study of catalyst cured LaRC-160/Celion 6000 composites

    NASA Technical Reports Server (NTRS)

    Edelman, R.

    1980-01-01

    LaRC 160 polyimide was modified with a high temperature peroxide catalyst, USP-138, in an attempt to reduce the final cure temperature to below 316 C. This effort was directed at obtaining a material for 177 C use that would cure at similar temperatures to a high performance epoxy while still maintaining the good moisture resistance of a polymide material. Attempts to prepare a laminate made from Celion 6000 fiber and 5% catalyzed LaRC 160 resin gave a material with minimal properties after curing at 193 C. Acceptable properties were not obtained until a final cure temperature of 260 C was used. A control laminate containing no catalyst and cured under the same conditions had only half the level of shear strength. The catalyzed LaRC 160 prepreg was also used to examine the possibility of shortening the conventional LaRC 160 cure at 316 C. Maximum properties were obtained using a 2.5% catalyzed product with a final cure temperature of 316 C held for fifteen minutes. Differences in properties between catalyzed and uncatalyzed product disappeared, however, when the cure time at 316 C was extended to 45 minutes.

  2. Accelerated Cure Project for Multiple Sclerosis

    MedlinePlus

    ... tweets Tweets by @AcceleratedCure Front The Accelerated Cure Project for MS is a non-profit, 501(c)( ... determines its causes and mechanisms. © 2016 Accelerated Cure Project. All rights reserved. Site Map Contact Us Privacy ...

  3. Slide Rule For Calculating Curing Schedules

    NASA Technical Reports Server (NTRS)

    Heater, Don

    1995-01-01

    Special-purpose slide rule devised for calculating schedules for storing and curing adhesives, sealants, and other materials characterized by known curing times and shelf lives. Prevents mistakes commonly made in determining storage and curing schedules.

  4. Clinical evaluation of a 35% hydrogen peroxide in-office whitening system.

    PubMed

    Papathanasiou, Aikaterini; Kastali, Samer; Perry, Ronald D; Kugel, Gerard

    2002-04-01

    This study evaluated the effectiveness of light-curing (heat conversion) vs no light-curing (no heat conversion) of a 35% hydrogen peroxide in-office tooth whitening system. Twenty patients with sound medical history (without tooth sensitivity) participated in this randomized, parallel clinical evaluation. Only six maxillary anterior teeth with discoloration and a tooth shade of A3 or darker were selected. Patients received a complete prophylaxis and were evaluated for initial (baseline) shade by three independent evaluators, precalibrated at 85% rater reliability in determining shades before the experiment began. Participants received a 20-minute chairside whitening treatment with a 35% hydrogen peroxide agent using a reflective resin barrier for gingival isolation. During the whitening treatment, the 35% hydrogen peroxide agent was light-activated with a halogen curing light on teeth Nos. 6 through 8 (Group I), but was not light-activated on teeth Nos. 9 through 11 (Group II). All patients returned 24 hours after the whitening application for shade evaluation. Although there were isolated instances (7 out of 20 patients) of greater degrees of lightening in the light-curing group, there was no statistically significant difference using the Mann-Whitney U test (P > .05). This study indicates that light-curing is optional with this 35% tooth whitening system. PMID:12789959

  5. Curing HIV: Moving Forward Faster.

    PubMed

    Flores, Marcella; Johnston, Rowena

    2016-02-01

    There is enormous enthusiasm in the scientific community for finding a cure for HIV. Although much remains to be discovered regarding the mechanisms of viral persistence and how it may be disrupted, some assumptions regarding the goals of a cure, applicability to target populations, and what is required of the assays we employ, may lead to missed opportunities and discoveries and hamper the discovery of a product that will safely cure tens of millions of HIV-infected people around the world. The field will benefit from an awareness and critical interrogation of assumptions that may be implicit in their scientific pursuits. PMID:26862662

  6. Diamine curing agents for polyurethanes

    NASA Technical Reports Server (NTRS)

    Bell, V. L.; St. Clair, T. L.

    1975-01-01

    Three aromatic diamines have properties that make them promising candidates as curing agents for converting isocyanates to polyurethanes with higher adhesive strengths, higher softening temperatures, better toughness, and improved abrasion resistance.

  7. Curing rate and flowing properties of silicone rubber at injection molding

    SciTech Connect

    Yoshino, M.; Nakamura, T. )

    1992-04-01

    Generally, silicone rubbers are mold-cured after mixing the rubber and peroxide curing agent with a two-roll mill or a kneader. Typically this is done at pressures of 5 MPa to 10 MPa and at temperatures between 120 to 200 C. Compression molding, transfer molding and injection molding are common molding ways for silicone rubbers. Recently, injection molding techniques are developing rapidly that have the advantages of molding automatically with high cycle mechanisms. To reduce the molding time and to make a precision part, both the flowing and curing properties of a particular rubber compound will be important. In this article, correlations between the curing and the flowing properties of silicone rubber are investigated by using the Rheovulkameter device.

  8. Lipid peroxidation and tissue damage.

    PubMed

    Mylonas, C; Kouretas, D

    1999-01-01

    In recent years it has become apparent that the oxidation of lipids, or lipid peroxidation, is a crucial step in the pathogenesis of several disease states in adult and infant patients. Lipid peroxidation is a process generated naturally in small amounts in the body, mainly by the effect of several reactive oxygen species (hydroxyl radical, hydrogen peroxide etc.). It can also be generated by the action of several phagocytes. These reactive oxygen species readily attack the polyunsaturated fatty acids of the fatty acid membrane, initiating a self-propagating chain reaction. The destruction of membrane lipids and the end-products of such lipid peroxidation reactions are especially dangerous for the viability of cells, even tissues. Enzymatic (catalase, superoxide dismutasse) and nonenzymatic (vitamins A and E) natural antioxidant defence mechanisms exist; however, these mechanisms may be overcome, causing lipid peroxidation to take place. Since lipid peroxidation is a self-propagating chain-reaction, the initial oxidation of only a few lipid molecules can result in significant tissue damage. Despite extensive research in the field of lipid peroxidation it has not yet been precisely determined if it is the cause or an effect of several pathological conditions. Lipid peroxidation has been implicated in disease states such as atherosclerosis, IBD, ROP, BPD, asthma, Parkinson's disease, kidney damage, preeclampsia and others. PMID:10459507

  9. A New Kind of Curing

    NASA Technical Reports Server (NTRS)

    2001-01-01

    A new curing method using automated tape placement (ATP) with electron beam (EB), or e-beam, produces a combination known as in situ e-beam curing. Through a Small Business Innovation Research (SBIR) contract from NASA's Marshall Space Flight Center, Science Research Laboratory, Inc., created the in situ e-beam curing technique, which uses a low-energy electron beam gun to cure various composite materials. One important benefit is the technique's utilization of room temperature curing, which lessens the chance of mismatching the thermal expansion coefficients of different materials. For instance, metals and composites will expand at different rates when heated, but the low-energy e-beam gun reduces the expansion differential. Using a low-energy gun also results in less x-ray shielding, significantly reduced capital costs, reduced facility space, and increased processing capabilities for larger parts. However, using a low-energy gun also means that each tape layer is treated individually because the gun can penetrate only one layer at a time. The e-beam gun emits lower energy x-rays, which are more easily shielded than those emitted by previous guns. The low-energy system is relatively portable due to its light weight and small size. The gun weighs about 70 pounds and can be easily mounted on a robotic arm or an ATP head.

  10. Heteroscedastic transformation cure regression models.

    PubMed

    Chen, Chyong-Mei; Chen, Chen-Hsin

    2016-06-30

    Cure models have been applied to analyze clinical trials with cures and age-at-onset studies with nonsusceptibility. Lu and Ying (On semiparametric transformation cure model. Biometrika 2004; 91:331?-343. DOI: 10.1093/biomet/91.2.331) developed a general class of semiparametric transformation cure models, which assumes that the failure times of uncured subjects, after an unknown monotone transformation, follow a regression model with homoscedastic residuals. However, it cannot deal with frequently encountered heteroscedasticity, which may result from dispersed ranges of failure time span among uncured subjects' strata. To tackle the phenomenon, this article presents semiparametric heteroscedastic transformation cure models. The cure status and the failure time of an uncured subject are fitted by a logistic regression model and a heteroscedastic transformation model, respectively. Unlike the approach of Lu and Ying, we derive score equations from the full likelihood for estimating the regression parameters in the proposed model. The similar martingale difference function to their proposal is used to estimate the infinite-dimensional transformation function. Our proposed estimating approach is intuitively applicable and can be conveniently extended to other complicated models when the maximization of the likelihood may be too tedious to be implemented. We conduct simulation studies to validate large-sample properties of the proposed estimators and to compare with the approach of Lu and Ying via the relative efficiency. The estimating method and the two relevant goodness-of-fit graphical procedures are illustrated by using breast cancer data and melanoma data. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26887342

  11. Challenging Roadblocks to Cancer Cure.

    PubMed

    Loda, Massimo

    2016-09-01

    The Pezcoller Symposium in Trento, Italy, June 2015, focused entirely on the question of why advanced cancer cure is so uncommon despite the extraordinarily rapid growth of invaluable therapeutic information. Participants were asked to define and to critically evaluate real and potential obstacles to permanent disease eradication. High-level concepts on potential road blocks to cures as well as opportunities for intervention in diverse areas of investigation ranging from genomic alterations to metabolism, microenvironment, immunity, and mechanotransduction were discussed. Provocative concepts and novel therapeutic avenues were proposed. What follows is a critical analysis of the highlights of this meeting. Cancer Res; 76(17); 4924-30. ©2016 AACR. PMID:27520451

  12. The viscoelasticity of curing thermosets

    SciTech Connect

    Adolf, D.; Martin, J.E.

    1990-01-01

    As a crosslinking polymer cures, dramatic changes in molecular architecture occur. These structural changes in turn affect the viscoelastic behavior of the material. At a critical extent of reaction (the gel point), the polymer undergoes a transition from a viscous liquid to an elastic solid. We have monitored the evolution of structure and viscoelasticity in an epoxy encapsulant used at Sandia, the diglycidyl ether of Bisphenol A (BADGE) cured with diethanolamine (DEA). The structure evolves according to percolation theory, and the viscoelasticity evolves according to out dynamic scaling theory for branched polymers. 7 refs., 4 figs.

  13. Advances in light curing adhesives

    NASA Astrophysics Data System (ADS)

    Bachmann, Andy

    2001-11-01

    This paper describes the development of a new family of light curing adhesives containing a new reactive additive previously not used in optical grade light curing adhesives are obtained with the addition of functionalized cellulositics. Outgassing as low as 10-6 grams/gram has been observed based on headspace sampling. Other additives have lowered the shrinkage rates of positioning adhesives from near 1 percent to less than 0.1 percent with fractional, percentage movements over thermal range of -40 degrees C to +200 degrees C.

  14. Dearomatization Reactions Using Phthaloyl Peroxide.

    PubMed

    Eliasen, Anders M; Christy, Mitchell; Claussen, Karin R; Besandre, Ronald; Thedford, Randal P; Siegel, Dionicio

    2015-09-18

    A new oxidative dearomatization reaction has been developed using phthaloyl peroxide to chemoselectively install two oxygen-carbon bonds into aromatic precursors. The oxidation reaction proceeds only once; addition of superstoichiometric equivalents of phthaloyl peroxide does not react further with the newly generated 1,3-cyclohexadiene. The reaction has been challenged by the addition of different functional groups and shown to maintain chemoselectivity. Due to the broad reactivity with 1,2-methylenedioxybenzene derivatives, linear free energy correlations were determined and support a mechanism proceeding through diradicals analogous to arene-hydroxylation reactions using phthaloyl peroxide. PMID:26333308

  15. Arene oxidation with malonoyl peroxides.

    PubMed

    Dragan, Andrei; Kubczyk, Tomasz M; Rowley, Julian H; Sproules, Stephen; Tomkinson, Nicholas C O

    2015-06-01

    Malonoyl peroxide 7, prepared in a single step from the commercially available diacid, is an effective reagent for the oxidation of aromatics. Reaction of an arene with peroxide 7 at room temperature leads to the corresponding protected phenol which can be unmasked by aminolysis. An ionic mechanism consistent with the experimental findings and supported by isotopic labeling, Hammett analysis, EPR investigations, and reactivity profile studies is proposed. PMID:25966313

  16. Stabilized aqueous hydrogen peroxide solution

    SciTech Connect

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  17. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent...

  18. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent...

  19. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent...

  20. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... acetone peroxide, with minor proportions of higher polymers, manufactured by reaction of hydrogen peroxide... grams to 10 grams of hydrogen peroxide equivalent per 100 grams of the additive, plus carrier, for use in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent...

  1. 7 CFR 30.10 - Cure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Cure. 30.10 Section 30.10 Agriculture Regulations of... AND STANDARDS Classification of Leaf Tobacco Covering Classes, Types and Groups of Grades § 30.10 Cure. To dry the sap from newly harvested tobacco by either natural or artificial process. Proper curing...

  2. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Pecans in the Shell 1 Definitions § 51.1412 Well cured. Well cured means that...

  3. 7 CFR 51.1412 - Well cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Pecans in the Shell 1 Definitions § 51.1412 Well cured. Well cured means that...

  4. Chromothriptic cure of WHIM syndrome.

    PubMed

    McDermott, David H; Gao, Ji-Liang; Liu, Qian; Siwicki, Marie; Martens, Craig; Jacobs, Paejonette; Velez, Daniel; Yim, Erin; Bryke, Christine R; Hsu, Nancy; Dai, Zunyan; Marquesen, Martha M; Stregevsky, Elina; Kwatemaa, Nana; Theobald, Narda; Long Priel, Debra A; Pittaluga, Stefania; Raffeld, Mark A; Calvo, Katherine R; Maric, Irina; Desmond, Ronan; Holmes, Kevin L; Kuhns, Douglas B; Balabanian, Karl; Bachelerie, Françoise; Porcella, Stephen F; Malech, Harry L; Murphy, Philip M

    2015-02-12

    Chromothripsis is a catastrophic cellular event recently described in cancer in which chromosomes undergo massive deletion and rearrangement. Here, we report a case in which chromothripsis spontaneously cured a patient with WHIM syndrome, an autosomal dominant combined immunodeficiency disease caused by gain-of-function mutation of the chemokine receptor CXCR4. In this patient, deletion of the disease allele, CXCR4(R334X), as well as 163 other genes from one copy of chromosome 2 occurred in a hematopoietic stem cell (HSC) that repopulated the myeloid but not the lymphoid lineage. In competitive mouse bone marrow (BM) transplantation experiments, Cxcr4 haploinsufficiency was sufficient to confer a strong long-term engraftment advantage of donor BM over BM from either wild-type or WHIM syndrome model mice, suggesting a potential mechanism for the patient's cure. Our findings suggest that partial inactivation of CXCR4 may have general utility as a strategy to promote HSC engraftment in transplantation. PMID:25662009

  5. HBV cure: why, how, when?

    PubMed

    Levrero, Massimo; Testoni, Barbara; Zoulim, Fabien

    2016-06-01

    Current HBV treatments control replication and liver disease progression in the vast majority of treated patients. However, HBV patients often require lifelong therapies due to the persistence of transcriptionally active viral cccDNA mini-chromosome in the nucleus, which is not directly targeted by current antiviral therapies. A true complete cure of HBV would require clearance of intranuclear cccDNA from all infected hepatocytes. An intermediate but still relevant step forward that would allow treatment cessation would be reaching a functional cure, equivalent to resolved acute infection, with a durable HBsAg loss±anti-HBs seroconversion, undetectable serum DNA and persistence of cccDNA in a transcriptionally inactive status. Recent advances in technologies and pharmaceutical sciences, including the cloning of the mayor HBV receptor (i.e. the NTCP transporter) and the development in vitro HBV infection models, have heralded a new horizon of innovative antiviral and immune-therapeutic approaches. PMID:27447092

  6. Radiation curing: Science and technology

    SciTech Connect

    Pappas, S.P.

    1992-01-01

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

  7. Cure shrinkage of thermoset composites

    SciTech Connect

    Russell, J.D. )

    1993-01-01

    The shrinkage of thermoset composites during cure was studied using a volumetric dilatometer. The material systems studied were AS4 carbon fiber/Hercules' 3501-6 epoxy, IM7 carbon fiber/Hercules 8551-7A toughened epoxy and IM7 carbon fiber/BASF's 5250-4 bismaleimide. Shrinkage of the samples due to both polymerization and thermal expansion effects was seen. The volume changes of the materials during cure were then compared to results from dynamic mechanical analysis (DMA) and dielectric cure monitoring. Maximums in volume corresponded to minimums in storage and loss modulus from DMA and maximums in the dielectric loss factor. Resin shrinkage during the 177 deg C (350 F) hold corresponded to the onset of polymerization seen by the rapid increase in the storage modulus and the decrease in the dielectric loss factor response due to reduced ion mobility. These results show that volumetric dilatometry can be an effective tool in the development of materials processing strategies and can be useful in studying residual stresses in composites. 9 refs.

  8. High Flow Addition Curing Polyimides

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Vannucci, Raymond D.; Ansari, Irfan; Cerny, Lawrence L.; Scheiman, Daniel A.

    1994-01-01

    A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (BTDB) for p-phenylenediamine (p -PDA) in a PMR-IL formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4'- (hexafluo- roisopropylidene) -diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the cor- responding PMR-11 polyimides. Long-term isothermal aging studies showed that BTDB- based 12F resins exhibited comparable thermo-oxidative stability to P-PDA based PMR-11 polyimides. The noncoplanar 2- and 2'-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal sta- bility of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343 C (650 F).

  9. Freud's psychoanalysis: a moral cure.

    PubMed

    Eriksson, Johan

    2014-08-01

    That psychoanalytical treatment in its classical Freudian sense is primarily a moral or ethical cure is not a very controversial claim. However, it is far from obvious how we are to understand precisely the moral character of psychoanalysis. It has frequently been proposed that this designation is valid because psychoanalysis strives neither to cure psychological symptoms pharmaceutically, nor to superficially modify the behaviour of the analysand, but to lead the analysand through an interpretive process during which he gradually gains knowledge of the unconscious motives that determine his behaviour, a process that might ideally liberate him to obtain, in relation to his inner desires, the status of a moral agent. There resides something appealing in these claims. But it is the author's belief that there is an even deeper moral dimension applying to psychoanalytical theory and praxis. Freudian psychoanalysis is a moral cure due to its way of thematizing psychological suffering as moral suffering. And this means that the moral subject - the being that can experience moral suffering - is not primarily something that the psychoanalytical treatment strives to realize, but rather the presupposition for the way in which psychoanalysis theorizes psychological problems as such. PMID:24720632

  10. Photo-Curing: UV Radiation curing of polymers

    NASA Technical Reports Server (NTRS)

    Inman, Christina A.

    2004-01-01

    The Polymers Branch of the Materials Division is dedicated to the development of high-performance for a variety of applications. Areas of significant interest include high- temperature polymers, low density, and high strength insulating materials, conductive polymers, and high density polymer electrolytes. This summer our group is working diligently on a photo-curing project. There is interest in the medical community feel the need for a new and improved balloon that will be used for angioplasty (a form of heart surgery). This product should maintain flexibility but add many other properties. Like possibly further processability and resistance to infection. Our group intends on coming up with this product by using photo-enolization (or simply, photo-curing) by Diels-Alder trapping. The main objective was to synthesize a series of new polymers by Diels-Alder cycloaddition of photoenols with more elastomeric properties. Our group was responsible for performing the proper photo-curing techniques of the polymers with diacrylates and bismaleimides, synthesizing novel monomers, and evaluating experimental results. We attempted to use a diacrylate to synthesize the polymer because of previous research done within the Polymers Branch here at NASA. Most acrylates are commercially available, have more elastometric properties than a typical rigid aromatic structure has and they contain ethylene oxides in the middle of their structure that create extensive flexibility. The problem we encountered with the acrylates is that they photo chemically and thermally self polymerize and create diradicals at low temperatures; these constraints caused a lot of unnecessary side reactions. We want to promote solely, diketone polymerization because this type of polymerization has the ability to cause very elastic polymers. We chose to direct our attention towards the usage of maleimides because they are known for eliminating these unnecessary side reactions.

  11. Progress toward hydrogen peroxide micropulsion

    SciTech Connect

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  12. Optimization of benzoyl peroxide concentration in an experimental bone cement based on poly(methyl methacrylate).

    PubMed

    Vazquez, B; Deb, S; Bonfield, W

    1997-07-01

    The effect of the concentration of benzoyl peroxide in poly(methyl methacrylate) bone cement formulations on their setting characteristics, particularly peak temperature and setting time, were studied. An optimization of the concentration of benzoyl peroxide was made with respect to curing parameters and compared with the residual monomer content. The mechanical properties of the different formulations were also determined and the results indicated that a composition of 1.5% wt/wt and 0.82% wt/wt of benzoyl peroxide and N,N-dimethyl-p-toluidine concentrations, respectively, gave the highest yield strength. Studies on the preparation of bone cement formulations containing different amounts of barium sulphate were also performed to assess the effect on the polymerization process and mechanical properties of the cements. PMID:15348730

  13. ASRM test report: Autoclave cure process development

    NASA Technical Reports Server (NTRS)

    Nachbar, D. L.; Mitchell, Suzanne

    1992-01-01

    ASRM insulated segments will be autoclave cured following insulation pre-form installation and strip wind operations. Following competitive bidding, Aerojet ASRM Division (AAD) Purchase Order 100142 was awarded to American Fuel Cell and Coated Fabrics Company, Inc. (Amfuel), Magnolia, AR, for subcontracted insulation autoclave cure process development. Autoclave cure process development test requirements were included in Task 3 of TM05514, Manufacturing Process Development Specification for Integrated Insulation Characterization and Stripwind Process Development. The test objective was to establish autoclave cure process parameters for ASRM insulated segments. Six tasks were completed to: (1) evaluate cure parameters that control acceptable vulcanization of ASRM Kevlar-filled EPDM insulation material; (2) identify first and second order impact parameters on the autoclave cure process; and (3) evaluate insulation material flow-out characteristics to support pre-form configuration design.

  14. Performance of concrete under different curing conditions

    SciTech Connect

    Tan, K.; Gjorv, O.E.

    1996-03-01

    The effect of curing conditions on strength and permeability of concrete was studied. Test results showed that after 3 and 7 days moist curing only the concretes with w/c ratios equal to or less than 0.4 were accepted, while after 28 days of moist curing however, even the concrete with w/c of 0.6 could be accepted. Silica fume has a significant effect on the resistance to water penetration. For the concretes both with and without silica fume and with w/c + s of 0.5, the 28-day compressive strengths of 3 and 7 days moist curing were higher than those of 28 days moist curing, and the silica fume concrete seemed to be less sensitive to early drying. The curing temperatures did not affect the water penetration of concrete, but affected the chloride penetration and compressive strength of concrete significantly.

  15. Inner-shell excitation spectroscopy of peroxides

    NASA Astrophysics Data System (ADS)

    Harding, K. L.; Kalirai, S.; Hayes, R.; Ju, V.; Cooper, G.; Hitchcock, A. P.; Thompson, M. R.

    2015-11-01

    O 1s inner-shell excitation spectra of a number of vapor phase molecules containing peroxide bonds - hydrogen peroxide (H2O2), di-t-butylperoxide (tBuOtBu), benzoyl peroxide, ((C6H5(CO)O)2), luperox-F [1,3(4)-bis(tertbutylperoxyisopropyl) benzene], and analogous, non-peroxide compounds - water, t-butanol and benzoic acid have been measured. C 1s spectra are also reported. O 1s spectra of solid benzoic acid, di-t-butylperoxide and luperox-F recorded using a scanning transmission X-ray microscope, are also reported, and compared to the corresponding gaseous spectra. Spectral interpretation was aided by comparing the spectra of the peroxide and non-peroxide counterparts and with ab initio calculations. A characteristic O 1s → σ∗O-O transition at 533.0(3) eV is identified in each peroxide species, which is absent in the corresponding non-peroxide counterpart species. The energy and intensity of the 533 eV peroxide feature is stable and thus useful for analysis of peroxides in mixtures, such as tracking residual peroxide initiators, or peroxides produced in fuel cells.

  16. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may...

  17. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  18. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  19. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  20. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may...

  1. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  2. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....C. 552(a) and 1 CFR part 51. You may obtain copies from the United States Pharmacopeial Convention... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may...

  3. Safety Tips: Peroxides Can Be Treacherous.

    ERIC Educational Resources Information Center

    Nagel, Miriam C.

    1984-01-01

    Peroxides are unstable, shock-, thermal-, and friction-sensitive compounds whose sensitivity increases with concentration. In addition, peroxides can form in aging organic solvents and stored alkali metals. Cautions related to storage, use, and disposal of peroxides in the secondary school chemistry laboratory are discussed. (JN)

  4. Improved dual flow aluminum hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart L.; Matthews, Donna

    1993-11-01

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  5. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  6. Sampling Stoichiometry: The Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Clift, Philip A.

    1992-01-01

    Describes a demonstration of the decomposition of hydrogen peroxide to provide an interesting, quantitative illustration of the stoichiometric relationship between the decomposition of hydrogen peroxide and the formation of oxygen gas. This 10-minute demonstration uses ordinary hydrogen peroxide and yeast that can be purchased in a supermarket.…

  7. Investigation of Film Curing by Dielectric Analysis.

    NASA Astrophysics Data System (ADS)

    Guma, Noemi Candelaria

    1995-01-01

    Dielectric analysis (DEA) relies on the response of molecules to a changing electric field. Permittivity (epsilon^') is a parameter obtained from DEA, which is proportional to the amount of molecular alignment (or motion). A DEA methodology was developed to evaluate and classify the degree of cure of films, and to demonstrate the mechanism of the curing phenomenon at a molecular level. The model material employed in the study was Eudragit^circler RS30D, an aqueous-based film forming polymeric material, containing 20% acetyl tributyl citrate as plasticizer. The data showed changes in the dielectric behavior of the polymer molecules in films that were subjected to accelerated stability or improper curing conditions. These dielectric changes were also manifested as changes in the permeability characteristics of the film, which ultimately influenced the final performance of the dosage form. By monitoring the dielectric behavior of the coating material during a curing cycle, a classification of three stages of curing was developed, namely undercured, optimally cured, and overcured. The changes in dielectric properties of the film reflected the changes in molecular structure, which correlated with changes in permeability and surface morphology. Based on the data, a mechanism of improper cure was proposed, which contends that the curing phenomenon is driven by two major forces, namely: the heterogenous loss and/or redistribution of plasticizer molecules during the curing process and the development of strain in the film structure during the coating process. A mathematical equation was derived to predict the epsilon^' of film-coated beads based on the epsilon^ ' data of free films cured under the same conditions. The model is based on the premise that "equal epsilon^' denotes equal mobility" for the same material, whether as free film or applied onto a substrate. The DEA technique developed and the proposed rationale of the curing phenomenon may be useful in optimizing the

  8. Interfacial Properties of Electron Beam Cured Composites

    SciTech Connect

    Eberle, C.C.

    1999-12-30

    The objectives of the CRADA are to: Confirm that fiber-resin adhesion is responsible for the observed poor shear properties; Determine the mechanism(s) responsible for poor adhesion between carbon fibers and epoxy resins after e-beam curing; Develop and evaluate resin systems and fiber treatments to improve the properties of e-beam cured, carbon-fiber-reinforced composites; and Develop refined methods for processing e-beam cured, carbon-fiber-reinforced composites.

  9. Effect of amine activators on the properties of chemical cured dental composites.

    PubMed

    Mathew, L; Joseph, R; Krishnan, V K

    1997-01-01

    The purpose of this study was to evaluate the reactivity and the effect of concentration of three tertiary amines upon the mechanical properties of a chemical curing dental composite. Chemical cured composite pastes were prepared by keeping peroxide concentration constant at 1 wt% (by weight of resin mixture) and by varying the amine/peroxide molar ratio from 0.25 to 1.5. Composite samples were prepared for all three amine pastes aged for 1, 15, 30, 45, and 60 d stored at 8, 22, and 37 degrees C. The loss in activity of the tertiary amine with time was measured. Changes in compressive strength, diametral tensile strength, and microhardness were also measured. A sharp decrease in working and setting times corresponding to increased activity was noticed with an increased amine content. The activity was found to vary in the order N,N-dimethyl p-toluidine (DMPT) > 2-(4-dimethylaminophenyl)ethanol (DMAPEA) > N,Ndiethanol p-toluidine (DEPT). DMPT is found to be more temperature sensitive than DMAPEA and DEPT. However, DEPT is found to provide better storage stability out of all three amines tested. Each amine was found to possess optimum concentrations at which the mechanical properties showed maximum values. DEPT is preferred for long-term storage stability in chemical-cured dental composites where aging tends to reduce the activity of the amine. PMID:9067811

  10. [Nonnius and the Spa cure].

    PubMed

    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. PMID:8848877

  11. Hepatitis C, stigma and cure

    PubMed Central

    Marinho, Rui Tato; Barreira, David Pires

    2013-01-01

    The infection with hepatitis C virus (HCV) is one of the most important global chronic viral infections worldwide. It is estimated to affect around 3% of the world population, about 170-200 million people. Great part of the infections are asymptomatic, the patient can be a chronic carrier for decades without knowing it. The most severe consequences of the chronic infection are liver cirrhosis and hepatocellular carcinoma, which appears in 20%-40% of the patients, leading to hepatic failure and death. The HCV was discovered 25 years ago in 1989, is a RNA virus and classified by the World Health Organization as an oncogenic one. Hepatocellular carcinoma is one of the most important cancers, the fifth worldwide in terms of mortality. It has been increasing in the Ocidental world, mainly due to chronic hepatitis C. Hepatitis C is not only a liver disease and a cause of cirrhosis, but also a mental, psychological, familiar, and social disease. The stigma that the infected person sometimes carries is tremendous having multiple consequences. The main cause is lack of adequate information, even in the health professionals setting. But, besides the “drama” of being infected, health professionals, family, society and the infected patients, must be aware of the chance of real cure and total and definitive elimination of the virus. The treatment for hepatitis C has begun in the last 80´s with a percentage of cure of 6%. Step by step the efficacy of the therapy for hepatitis C is rapidly increasing and nowadays with the very new medications, the so called Direct Antiviral Agents-DAAs of new generation, is around 80%-90%. PMID:24187444

  12. Improved Electrolytic Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    James, Patrick I.

    2005-01-01

    An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

  13. NASA Hydrogen Peroxide Propulsion Perspective

    NASA Technical Reports Server (NTRS)

    Unger, Ronald; Lyles, Garry M. (Technical Monitor)

    2002-01-01

    This presentation is to provide the current status of NASA's efforts in the development of hydrogen peroxide in both mono-propellant and bi-propellant applications, consistent with the Space Launch Initiative goals of pursuing low toxicity and operationally simpler propellants for application in the architectures being considered for the 2nd Generation Reusable Launch Vehicle, also known as the Space Launch Initiative, or SLI.

  14. Wet peroxide degradation of atrazine.

    PubMed

    Rodríguez, Eva M; Alvarez, Pedro M; Rivas, F Javier; Beltrán, Fernando J

    2004-01-01

    The high temperature (150-200 degrees C), high pressure (3.0-6.0 MPa) degradation of atrazine in aqueous solution has been studied. Under these extreme conditions atrazine steadily hydrolyses in the absence of oxidising agents. Additionally, oxygen partial pressure has been shown not to affect atrazine degradation rates. In no case mineralisation of the parent compound was observed. The addition of the free radical generator hydrogen peroxide to the reaction media significantly enhanced the depletion rate of atrazine. Moreover, partial mineralisation of the organics was observed when hydrogen peroxide was used. Again, oxygen presence did not influence the efficiency of the promoted reaction. Consecutive injections of hydrogen peroxide throughout the reaction period brought the total carbon content conversion to a maximum of 65-70% after 40 min of treatment (suggesting the total conversion of atrazine to cyanuric acid). Toxicity of the effluent measured in a luminometer decreased from 93% up to 23% of inhibition percentage. The process has been simulated by means of a semi-empirical model. PMID:14559259

  15. [Space flight and peroxidative damage].

    PubMed

    Yang, Tang-bin; Zhong, Ping; Qu, Li-na; Yuan, Yan-hong

    2003-12-01

    Space flight is associated with an increase of peroxidative damage after returning to 1 g. The effect is more pronounced after long-duration space flight and can even last for several weeks after landing. In humans there is increased lipid peroxidation in erythrocyte membranes, reduced blood antioxidants, and increased urinary excretion of 8-iso-prostaglandin F2alpha, and 8-oxo-7, 8 dihydro-2 deoxyguanosine. Isoprostane 8-iso-prostaglandin F2alpha and 8-oxo-7, 8 dihydro-2 deoxyguanosine are markers for oxidative damage to lipids and DNA, respectively. The changes are attributed to a combination of energy deficiency that occurs during flight and substrate competition for amino acids occurring between repleted muscle and other tissues during the recovery phase. The observations in humans have been complemented by studies in rodents, which showed increased production of lipid peroxidation products and decreased antioxidant enzyme activity afterflight. The changes in rodents were attributed to the stress associated with re-entry into Earth's gravity. Reducing the imbalance between the production of endogenous oxidant defenses and oxidant production by increasing the supply antioxidants in diet may lessen the severity of the postflight increase in oxidative stress. PMID:15008196

  16. A new hypothesis on HIV cure

    PubMed Central

    Hladik, Florian

    2015-01-01

    In this opinion article, I provide the rationale for my hypothesis that nucleoside reverse transcriptase inhibitors (NRTIs) may prevent human immunodeficiency virus (HIV) cure by promoting the survival of cells with integrated provirus. If correct, we may be closer to a cure than we realize. PMID:26380071

  17. Ultrasonic mixing of epoxy curing agents

    NASA Technical Reports Server (NTRS)

    Hodges, W. T.; St.clair, T. L.

    1983-01-01

    A new technique for mixing solid curing agents into liquid epoxy resins using ultrasonic energy was developed. This procedure allows standard curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents with very high melt temperatures such as 4,4 prime-diaminobenzophenone (4,4 prime-DABP) (242 C) to be mixed without premature curing. Four aromatic diamines were ultrasonically blended into MY-720 epoxy resin. These were 4,4 prime-DDS; 3,3 prime-DDA; 4,4 prime-DABP and 3,3 prime-DABP. Unfilled moldings were cast and cured for each system and their physical and mechanical properties compared.

  18. Animal Models for HIV Cure Research

    PubMed Central

    Policicchio, Benjamin B.; Pandrea, Ivona; Apetrei, Cristian

    2016-01-01

    The HIV-1/AIDS pandemic continues to spread unabated worldwide, and no vaccine exists within our grasp. Effective antiretroviral therapy (ART) has been developed, but ART cannot clear the virus from the infected patient. A cure for HIV-1 is badly needed to stop both the spread of the virus in human populations and disease progression in infected individuals. A safe and effective cure strategy for human immunodeficiency virus (HIV) infection will require multiple tools, and appropriate animal models are tools that are central to cure research. An ideal animal model should recapitulate the essential aspects of HIV pathogenesis and associated immune responses, while permitting invasive studies, thus allowing a thorough evaluation of strategies aimed at reducing the size of the reservoir (functional cure) or eliminating the reservoir altogether (sterilizing cure). Since there is no perfect animal model for cure research, multiple models have been tailored and tested to address specific quintessential questions of virus persistence and eradication. The development of new non-human primate and mouse models, along with a certain interest in the feline model, has the potential to fuel cure research. In this review, we highlight the major animal models currently utilized for cure research and the contributions of each model to this goal. PMID:26858716

  19. Framing expectations in early HIV cure research.

    PubMed

    Dubé, Karine; Henderson, Gail E; Margolis, David M

    2014-10-01

    Language used to describe clinical research represents a powerful opportunity to educate volunteers. In the case of HIV cure research there is an emerging need to manage expectations by using the term 'experiment'. Cure experiments are proof-of-concept studies designed to evaluate novel paradigms to reduce persistent HIV-1 reservoirs, without any expectation of medical benefit. PMID:25280965

  20. Animal Models for HIV Cure Research.

    PubMed

    Policicchio, Benjamin B; Pandrea, Ivona; Apetrei, Cristian

    2016-01-01

    The HIV-1/AIDS pandemic continues to spread unabated worldwide, and no vaccine exists within our grasp. Effective antiretroviral therapy (ART) has been developed, but ART cannot clear the virus from the infected patient. A cure for HIV-1 is badly needed to stop both the spread of the virus in human populations and disease progression in infected individuals. A safe and effective cure strategy for human immunodeficiency virus (HIV) infection will require multiple tools, and appropriate animal models are tools that are central to cure research. An ideal animal model should recapitulate the essential aspects of HIV pathogenesis and associated immune responses, while permitting invasive studies, thus allowing a thorough evaluation of strategies aimed at reducing the size of the reservoir (functional cure) or eliminating the reservoir altogether (sterilizing cure). Since there is no perfect animal model for cure research, multiple models have been tailored and tested to address specific quintessential questions of virus persistence and eradication. The development of new non-human primate and mouse models, along with a certain interest in the feline model, has the potential to fuel cure research. In this review, we highlight the major animal models currently utilized for cure research and the contributions of each model to this goal. PMID:26858716

  1. Cure Chemistry of Phenylethynyl Terminated Oligomers

    NASA Technical Reports Server (NTRS)

    Wood, Karen H.; Orwoll, Robert A.; Young, Philip R.; Jensen, Brian J.; McNair, Harold M.

    1997-01-01

    The ability to process high performance polymers into quality, void-free composites has been significantly advanced using oligomers terminated with reactive groups which cure or crosslink at elevated temperature without the evolution of volatile byproducts. Several matrix resin systems of considerable interest to the aerospace community utilize phenylethynyl-terminated imide (PETI) technology to achieve this advantage. The present paper addresses the cure chemistry of PETI oligomers. The thermal cure of a low molecular weight model compound was studied using a variety of analytical techniques including differential scanning calorimetry, Fourier transform infrared spectroscopy, and liquid chromatography-mass spectroscopy. The studies indicate an extremely complex cure process. Many stable products were isolated and this paper reports current work on identification of those products. The intent of this research is to provide fundamental insight into the molecular structure of the cured PETI engineering materials so that performance and durability can be more fully assessed.

  2. Biodegradable Epoxy Networks Cured with Polypeptides

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigeo; Kramer, Edward J.

    2006-03-01

    Epoxy resins are used widely for adhesives as well as coatings. However, once cured they are usually highly cross-linked and are not biodegradable. To obtain potentially biodegradable polypeptides that can cure with epoxy resins and achieve as good properties as the conventional phenol novolac hardeners, poly(succinimide-co-tyrosine) was synthesized by thermal polycondensation of L-aspartic acid and L-tyrosine with phosphoric acid under reduced pressure. The tyrosine/succinimide ratio in the polypeptide was always lower than the tyrosine/(aspartic acid) feed ratio and was influenced by the synthesis conditions. Poly(succinimide-tyrosine- phenylalanine) was also synthesized from L-aspartic acid, L- tyrosine and L-phenylalanine. The thermal and mechanical properties of epoxy resins cured with these polypeptides are comparable to those of similar resins cured with conventional hardeners. In addition, enzymatic degradability tests showed that Chymotrypsin or Subtilisin A could cleave cured films in an alkaline borate buffer.

  3. Knowledge based control for microwave curing of polymer composite materials

    SciTech Connect

    Hawkins, R.; Sticklen, J.; Hawley, M.C.

    1996-12-31

    Traditionally, the majority of thermoset composite materials have been autoclave cured. Some alternatives to curing in an autoclave include E-Beam and microwave curing. In the Microwave Research Group at MSU, microwave curing technology is being pursued for the purpose of achieving higher throughput, lower cost and higher energy efficiency, relative to autoclave curing.

  4. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured under... 7 Agriculture 2 2010-01-01 2010-01-01 false Fire-cured. 29.2519 Section 29.2519...

  5. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured under... 7 Agriculture 2 2012-01-01 2012-01-01 false Fire-cured. 29.2519 Section 29.2519...

  6. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured under... 7 Agriculture 2 2011-01-01 2011-01-01 false Fire-cured. 29.2519 Section 29.2519...

  7. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured under... 7 Agriculture 2 2013-01-01 2013-01-01 false Fire-cured. 29.2519 Section 29.2519...

  8. 7 CFR 29.2519 - Fire-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... INSPECTION Standards Official Standard Grades for Kentucky and Tennessee Fire-Cured and Foreign-Grown Fire-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2519 Fire-cured. Tobacco cured under... 7 Agriculture 2 2014-01-01 2014-01-01 false Fire-cured. 29.2519 Section 29.2519...

  9. 9 CFR 319.103 - Cured beef tongue.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Cured beef tongue. 319.103 Section 319... Cured beef tongue. In preparing “Cured Beef Tongue,” the application of curing solution to the fresh beef tongue shall not result in an increase in the weight of the cured beef tongue of more than...

  10. 9 CFR 319.103 - Cured beef tongue.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Cured beef tongue. 319.103 Section 319... Cured beef tongue. In preparing “Cured Beef Tongue,” the application of curing solution to the fresh beef tongue shall not result in an increase in the weight of the cured beef tongue of more than...

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

    NASA Technical Reports Server (NTRS)

    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.

  12. Synthetic ozonide drug candidate OZ439 offers new hope for a single-dose cure of uncomplicated malaria.

    PubMed

    Charman, Susan A; Arbe-Barnes, Sarah; Bathurst, Ian C; Brun, Reto; Campbell, Michael; Charman, William N; Chiu, Francis C K; Chollet, Jacques; Craft, J Carl; Creek, Darren J; Dong, Yuxiang; Matile, Hugues; Maurer, Melanie; Morizzi, Julia; Nguyen, Tien; Papastogiannidis, Petros; Scheurer, Christian; Shackleford, David M; Sriraghavan, Kamaraj; Stingelin, Lukas; Tang, Yuanqing; Urwyler, Heinrich; Wang, Xiaofang; White, Karen L; Wittlin, Sergio; Zhou, Lin; Vennerstrom, Jonathan L

    2011-03-15

    Ozonide OZ439 is a synthetic peroxide antimalarial drug candidate designed to provide a single-dose oral cure in humans. OZ439 has successfully completed Phase I clinical trials, where it was shown to be safe at doses up to 1,600 mg and is currently undergoing Phase IIa trials in malaria patients. Herein, we describe the discovery of OZ439 and the exceptional antimalarial and pharmacokinetic properties that led to its selection as a clinical drug development candidate. In vitro, OZ439 is fast-acting against all asexual erythrocytic Plasmodium falciparum stages with IC(50) values comparable to those for the clinically used artemisinin derivatives. Unlike all other synthetic peroxides and semisynthetic artemisinin derivatives, OZ439 completely cures Plasmodium berghei-infected mice with a single oral dose of 20 mg/kg and exhibits prophylactic activity superior to that of the benchmark chemoprophylactic agent, mefloquine. Compared with other peroxide-containing antimalarial agents, such as the artemisinin derivatives and the first-generation ozonide OZ277, OZ439 exhibits a substantial increase in the pharmacokinetic half-life and blood concentration versus time profile in three preclinical species. The outstanding efficacy and prolonged blood concentrations of OZ439 are the result of a design strategy that stabilizes the intrinsically unstable pharmacophoric peroxide bond, thereby reducing clearance yet maintaining the necessary Fe(II)-reactivity to elicit parasite death. PMID:21300861

  13. [Little histories of magnetic cures].

    PubMed

    Pinet, Patrice

    2009-02-01

    Men were very early fascinated by magnetism because of its manifest and particular working at distance, which looked different of gravity. It was tryed to be explained by mecanism, for exemple Descartes and Boyle. Paracelse valued the therapeutics with magnets and conceived medicines as working by a magnetic virtue. Gilbert limited the medicinal properties of magnet but helded it to be animated. Many authors praised remedies that work at distance of the evil as Bacon, Van Helmont, Croll, Porta, Goclenius, Digby. Such a belief related to magic ideas of this time. In the Bacon's way Boyle collected facts of magnetic cures, and his actual testing of the divisibility of bodies led him to conceive imponderable corpuscles. Newton supposed a subtil and universel fluid going through every solid body. Mesmer misappropriated this idea by founding the animal magnetism of which physical working was only proceeding from the inside of the patient by an effect of suggestion (psychosomatic). Homeopathy took again the notion of remedies having an infinite or a magnetic virtue, which partly issued from Paracelse's and Mesmer's doctrines, which were extolled in Germany at the time of Hahnemann. The latter decided in favour of a spiritualist and not corpuscular interpretation of the working of his homeopathic medicines. PMID:19579649

  14. Coating for components requiring hydrogen peroxide compatibility

    NASA Technical Reports Server (NTRS)

    Yousefiani, Ali (Inventor)

    2010-01-01

    The present invention provides a heretofore-unknown use for zirconium nitride as a hydrogen peroxide compatible protective coating that was discovered to be useful to protect components that catalyze the decomposition of hydrogen peroxide or corrode when exposed to hydrogen peroxide. A zirconium nitride coating of the invention may be applied to a variety of substrates (e.g., metals) using art-recognized techniques, such as plasma vapor deposition. The present invention further provides components and articles of manufacture having hydrogen peroxide compatibility, particularly components for use in aerospace and industrial manufacturing applications. The zirconium nitride barrier coating of the invention provides protection from corrosion by reaction with hydrogen peroxide, as well as prevention of hydrogen peroxide decomposition.

  15. Lipid Peroxidation in Higher Plants 1

    PubMed Central

    Schmidt, Arno; Kunert, Karl Josef

    1986-01-01

    To study the role of glutathione reductase in lipid peroxidation, bean leaves (Phaseolus vulgaris) cv Fori were treated with the herbicide acifluorfen-sodium (sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid). Acifluorfen is a potent inducer of lipid peroxidation. In beans, decrease of acid-soluble SH-compounds and lipid peroxidation, measured as ethane evolution, were the toxic events after treatment of leaves with acifluorfen. As a primary response to peroxidation, increased production of antioxidants, such as vitamin C and glutathione, was found. This was followed by elevation of glutathione reductase activity. Enhanced activity of the enzyme prevented both further decline of acid-soluble SH-compounds and lipid peroxidation. Increased production of antioxidants and elevated activity of antioxidative enzymes, like glutathione reductase, seem to be a general strategy to limit toxic peroxidation in plants. PMID:16665095

  16. [Is it possible to cure HIV infection?].

    PubMed

    Gutiérrez, Carolina; Madrid, Nadia P; Moreno, Santiago

    2015-09-01

    Antiretroviral therapy has significantly improved the life expectancy in HIV-infected people, but it cannot cure the disease by itself. Several barriers have been identified for the cure of HIV infection, including a reservoir of latently infected cells, persistent viral replication in tissues, and anatomical sanctuaries. The main strategy proposed for the cure of HIV consists on the administration of drugs that, through the reactivation of latent HIV, would eliminate the cell reservoir. Ongoing clinical trials have shown the proof of concept, but the efficacy of these drugs in decreasing the reservoir size has not been proved so far. PMID:26365737

  17. PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

    DOEpatents

    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. Hydrogen peroxide on the surface of Europa

    USGS Publications Warehouse

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  19. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  20. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  1. Hydrogen peroxide on the surface of Europa.

    PubMed

    Carlson, R W; Anderson, M S; Johnson, R E; Smythe, W D; Hendrix, A R; Barth, C A; Soderblom, L A; Hansen, G B; McCord, T B; Dalton, J B; Clark, R N; Shirley, J H; Ocampo, A C; Matson, D L

    1999-03-26

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis. PMID:10092224

  2. Hydrogen peroxide, from Wieland to Sies.

    PubMed

    Koppenol, Willem H

    2016-04-01

    A history of the formation of hydrogen peroxide in vivo is presented, starting with the discovery of catalase. The first hypothesis was formulated by Heinrich Wieland, who assumed that dioxygen reacted directly with organic molecules. This view was strongly criticised by Otto Warburg, Helmut Sies' academic grandfather. The involvement of hydrogen peroxide in physiological processes was investigated by Theodor Bücher, the "Doktorvater" of Helmut. Helmut's research made it possible to quantitate hydrogen peroxide in tissues. PMID:27095207

  3. [Mineral water as a cure].

    PubMed

    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

  4. Oxidative cleavage of cycloalkanones by hydrogen peroxide

    SciTech Connect

    Starostin, E.K.; Aleksandrov, A.V.; Nikishin, G.I.

    1986-07-10

    The authors have studied the reaction of cyclopentanone, cyclohexanone, cycloheptanone, and cyclododecanone with aqueous hydrogen peroxide over the temperature range 110-150/sup 0/C. The effects of temperature, hydrogen peroxide concentration, and the molar proportions of the reagents on the composition and yields of the products have been examined in the case of cyclohexanone. Oxidation of cyclohexanone by aqueous hydrogen peroxide at 110-150/sup 0/C gives 1,10-decanedicarboxylic acid and hexanoic acid as the principal products. Cyclopentanone and cycloheptanone react with hydrogen peroxide similarly to cyclohexanone, giving sebacic and pentanoic acids, and 1,12-dodecanedicarboxylic acids, respectively.

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

    NASA Astrophysics Data System (ADS)

    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 duri

  6. Thread-Pull Test Of Curing Adhesive

    NASA Technical Reports Server (NTRS)

    Johnson, James A.

    1992-01-01

    Hardness (and degree of cure) of adhesive layer measured by pulling previously inserted thread out of layer. Strength of bond measured directly on assembly rather than on samples, which can be misleading.

  7. Inelastic micromechanics of curing stresses in composites

    NASA Technical Reports Server (NTRS)

    Foye, R. L.

    1975-01-01

    The combined finite element/laminate analysis method is used to study the thermal curing stresses in composite materials with a nonlinearly elastic matrix subject to creep. The application of this analysis to boron/epoxy composites shows that curing stress levels in the laminate are of sufficient magnitude to cause widespread yielding in the matrix. The stress levels, based on the creep analysis of a typical laminate cure cycle, indicate that the residual stresses can vary from 80 to 100% of the residual stress estimates based on linear thermoelastic analysis. It is shown that there is virtually no change in the static longitudinal or shear response of unidirectional and cross-ply boron/epoxy laminates as a result of curing stresses. Results of a series of constant-stress, high temperature creep tests are presented.

  8. Curing of Furfuryl Alcohol-Impregnated Parts

    NASA Technical Reports Server (NTRS)

    Lawton, J. W.; Brayden, T. H.

    1983-01-01

    Delamination problem in reinforced carbon/carbon parts impregnated with oxalic acid-catalyzed furfuryl alcohol overcome by instituting two additional quality-control tests on alcohol and by changing curing conditions.

  9. Financing cures in the United States.

    PubMed

    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. PMID:25482146

  10. Susan G. Komen for the Cure

    MedlinePlus

    ... Washington West Virginia Wisconsin Wyoming -INTERNATIONAL- Bahamas Belgium Bosnia and Herzegovina Georgia Germany Greece Italy Tanzania Uzbekistan ... TX Saturday, October 1, 2016 Susan G. Komen Bosnia and Herzegovina Race for the Cure Sarajevo, N/ ...

  11. Fast Curing of Composite Wood Products

    SciTech Connect

    Dr. Arthur J. Ragauskas

    2006-04-26

    The overall objective of this program is to develop low temperature curing technologies for UF and PF resins. This will be accomplished by: • Identifying the rate limiting UF and PF curing reactions for current market resins; • Developing new catalysts to accelerate curing reactions at reduced press temperatures and times. In summary, these new curing technologies will improve the strength properties of the composite wood products and minimize the detrimental effects of wood extractives on the final product while significantly reducing energy costs for wood composites. This study is related to the accelerated curing of resins for wood composites such as medium density fiberboard (MDF), particle board (PB) and oriented strandboard (OSB). The latter is frequently manufactured with a phenol-formaldehyde resin whereas ureaformaldehyde (UF) resins are usually used in for the former two grades of composite wood products. One of the reasons that hinder wider use of these resins in the manufacturing of wood composites is the slow curing speed as well as inferior bondability of UF resin. The fast curing of UP and PF resins has been identified as an attractive process development that would allow wood to be bonded at higher moisture contents and at lower press temperatures that currently employed. Several differing additives have been developed to enhance cure rates of PF resins including the use of organic esters, lactones and organic carbonates. A model compound study by Conner, Lorenz and Hirth (2002) employed 2- and 4-hydroxymethylphenol with organic esters to examine the chemical basis for the reported enhanced reactivity. Their studies suggested that the enhance curing in the presence of esters could be due to enhanced quinone methide formation or enhanced intermolecular SN2 reactions. In either case the esters do not function as true catalysts as they are consumed in the reaction and were not found to be incorporated in the polymerized resin product. An

  12. Tracking Polymer Cure Via Embedded Optical Fibers

    NASA Technical Reports Server (NTRS)

    Dean, David L.; Davidson, T. Fred

    1993-01-01

    Fourier-transform infrared spectroscopy applied in interior of specimen of material by bringing infrared light through specimen in optical fiber. Light interacts with material via evanescent-wave effect. Spectra obtained in this way at various times during curing process also combined with data from ultrasonic, thermographic, and dielectric-impedance monitoring, and other measurement techniques to obtain more complete characterization of progress of curing process.

  13. New advanced shotcrete admixtures: Internal curing

    SciTech Connect

    Melbye, T.A.

    1995-12-31

    Tunnels and other underground construction projects have one of the worst curing conditions due to the ventilation that blows continuously dry (cold or hot) air into the tunnel. It can be compared with concrete exposed to a windy area. One would think that tunnels have ideal curing conditions with high humidity (water leakage), no wind and no sun exposure. However, this is not the case. MBT has developed a new system for more efficient and secure curing of wet shotcrete, repair mortars as well as concrete. Internal curing means that a special admixture is added to the concrete/mortar during batching as a normal admixture. This admixture produces an internal barrier in the shotcrete/concrete which secures safer hydration and better chemical resistance than the application of conventional curing agents. The benefits resulting from the new technology are impressive: The time consuming application and, in the case of various shotcrete layers, removal of curing agents are no longer necessary; curing is guaranteed from the very beginning of hydration; and there is no negative influence on bonding between layers. As a consequence of th is optimum curing effect, all other shotcrete characteristics are improved: density, final strengths, freeze/thaw and chemical resistances, watertightness, less cracking and shrinkage. In addition, MEYCO TCC 735 also improves pumpability and workability of shotcrete, even with low-grade aggregates. It particularly improves the pumpability of steel fiber reinforced shotcrete mixes. In combination with the MEYCO TCC system it contrives to even increase the beneficial effects of the slump killing system by further improving fiber orientation, reducing fiber rebound and thus raising toughness values.

  14. High Power UV LED Industrial Curing Systems

    SciTech Connect

    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.

  15. Materials for single-etch double patterning process: surface curing agent and thermal cure resist

    NASA Astrophysics Data System (ADS)

    Bae, Young C.; Liu, Yi; Cardolaccia, Thomas; McDermott, John C.; Trefonas, Peter; Spizuoco, Ken; Reilly, Michael; Pikon, Amandine; Joesten, Lori; Zhang, Gary G.; Barclay, George G.; Simon, Julia; Gaurigan, Stéphanie

    2009-03-01

    Two different pattern curing techniques were developed to stabilize first lithographic images for the single-etch double patterning process. The first method uses a surface curing agent (SCA) that is coated on top of the patterned surface to form a protective coating layer during the curing bake process. It was found that the surface curing process with SCA offers minimum CD changes before and after the double patterning process. Virtually no CD change was observed with the first lithographic images at various curing bake temperatures ranging from 120 ~160°C indicating the curing reaction is limited on the patterned surface. The second method uses a thermal cure resist (TCR) that is a special 193nm photoresist with a crosslinkable functional group to form an insoluble network upon heating at higher temperature. A single-step curing process of the first lithographic images was achieved using TCR by baking the patterned images at 180°C for 60sec. A cross-line contact hole double patterning method was used to evaluate these two different curing techniques and both SCA and TCR successfully demonstrated their capability to print 45nm contact holes with excellent CD uniformity in immersion lithography (1.35NA) with a 45nm half pitch mask. It was also confirmed that both SCA and TCR can be extended to the top-coat free immersion double patterning process using an embedded barrier layer technique.

  16. Problem of the lithium peroxide thermal stability

    NASA Astrophysics Data System (ADS)

    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.

  17. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... proportions of higher polymers, manufactured by reaction of hydrogen peroxide and acetone. (b) The additive may be mixed with an edible carrier to give a concentration of: (1) 3 grams to 10 grams of hydrogen...; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per 100 grams of the additive,...

  18. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 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...

  19. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 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...

  20. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 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...

  1. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 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...

  2. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 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...

  3. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 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...

  4. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 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...

  5. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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...

  6. [Advances in peroxide-based decontaminating technologies].

    PubMed

    Xi, Hai-ling; Zhao, San-ping; Zhou, Wen

    2013-05-01

    With the boosting demand for eco-friendly decontaminants, great achievements in peroxide-based decontaminating technologies have been made in recent years. These technologies have been applied in countering chemical/biological terrorist attacks, dealing with chemical/biological disasters and destructing environmental pollutants. Recent research advances in alpha-nucleophilic/oxidative reaction mechanisms of peroxide-based decontamination against chemical warfare agents were reviewed, and some classical peroxide-based decontaminants such as aqueous decontaminating solution, decontaminating foam, decontaminating emulsions, decontaminating gels, decontaminating vapors, and some newly developed decontaminating media (e.g., peroxide-based self-decontaminating materials and heterogeneous nano-catalytic decontamination systems) were introduced. However, currently available peroxide-based decontaminants still have some deficiencies. For example, their decontamination efficiencies are not as high as those of chlorine-containing decontaminants, and some peroxide-based decontaminants show relatively poor effect against certain agents. More study on the mechanisms of peroxide-based decontaminants and the interfacial interactions in heterogeneous decontamination media is suggested. New catalysts, multifunctional surfactants, self-decontaminating materials and corrosion preventing technologies should be developed before peroxide-based decontaminants really become true "green" decontaminants. PMID:23914512

  7. Hydrogen peroxide as a greenhouse soil amendment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are anecdotal reports that hydrogen peroxide provides growth benefits beyond controlling plant infection and plant stress. The objective of this research was to determine the effect of soil applications of hydrogen peroxide solutions on plant growth and flowering. Nasturtium (Tropaeolum maju...

  8. Fundamentals of ISCO Using Hydrogen Peroxide

    EPA Science Inventory

    Hydrogen peroxide is a common oxidant that has been applied extensively with in situ chemical oxidation (ISCO). Because of its widespread use in this and other fields, it has been extensively researched. This research has revealed that hydrogen peroxide has very complex chemistry...

  9. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    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...

  10. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    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...

  11. Molecular Association and Structure of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  12. Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

    DOEpatents

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

    2010-11-09

    A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

  13. Rearrangements of organic peroxides and related processes

    PubMed Central

    Yaremenko, Ivan A; Vil’, Vera A; Demchuk, Dmitry V

    2016-01-01

    Summary 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. PMID:27559418

  14. Vapor Hydrogen Peroxide Sterilization Certification

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  15. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  16. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  17. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  18. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  19. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  20. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  1. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  2. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  3. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  4. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  5. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  6. 7 CFR 58.412 - Coolers or curing rooms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Coolers or curing rooms. 58.412 Section 58.412 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....412 Coolers or curing rooms. Coolers or curing rooms where cheese is held for curing or storage...

  7. 7 CFR 29.6002 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric conditions..., pole-burn, and shed-burn in damp weather. Air-cured tobacco should not carry the odor of smoke or...

  8. 7 CFR 29.3002 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.3002 Section 29.3002 Agriculture... Air-cured. Tobacco cured under natural atmospheric conditions. Artificial heat is sometimes used to control excess humidity during the curing period to prevent house-burn and barn-burn in damp weather....

  9. 7 CFR 29.3502 - Air-cured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.3502 Section 29.3502 Agriculture... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign Type 95) § 29.3502 Air-cured. Tobacco cured under natural atmospheric conditions without the use...

  10. Microcalorimetric Measurements of Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Davis, Dennis D.; Hornung, Steven D.; Baker, Dave L.

    1999-01-01

    Recent interest in propellants with nontoxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because hydrogen peroxide is sensitive to contaminants and materials interactions, stability and shelf life are issues. A relatively new, ultrasensitive heat measurement technique, isothermal microcalorimetry, is being used at the White Sands Test Facility to monitor the decomposition of hydrogen peroxide at near ambient temperatures. Isothermal microcalorimetry measures the beat flow from a reaction vessel into a surrounding heat sink. In these applications, microcalorimetry is approximately 1,000 times more sensitive than accelerating rate calorimetry or differential scanning calorimetry for measuring thermal events. Experimental procedures have been developed for the microcalorimetric measurement of the ultra-small beat effects caused by incompatible interactions of hydrogen peroxide. The decomposition rates of hydrogen peroxide at the picomole/sec/gram level have been measured showing the effects of stabilizers and peroxide concentration. Typical measurements are carried out at 40 C over a 24-hour period, This paper describes a method for the conversion of the heat flow measurements to chemical reaction rates based on thermochemical considerations. The reaction rates are used in a study of the effects of stabilizer levels on the decomposition of propellant grade hydrogen peroxide.

  11. Titanium corrosion in alkaline hydrogen peroxide environments

    NASA Astrophysics Data System (ADS)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  12. UV curing of nanoparticle reinforced acrylates

    NASA Astrophysics Data System (ADS)

    Bauer, F.; Flyunt, R.; Czihal, K.; Ernst, H.; Naumov, S.; Buchmeiser, M. R.

    2007-12-01

    To improve the surface hardness of radiation cured acrylate coatings, both silica nanoparticles and alumina particles with a few microns in size have been embedded into acrylate formulations. Regular mixing of nanoparticles into 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 of nanoparticles using trialkoxysilanes, which provide an interface between the two dissimilar materials. Nanoparticles modified by methacryloxypropyltrimethoxysilane (MEMO) and vinyltrimethoxysilane (VTMO), both having polymerisation-active groups, may be crosslinked with the acrylate resin. UV curing of the nanocomposites revealed an unexpected lower reactivity of the vinyl groups of VTMO modified silica compared to MEMO grafted on silica. For VTMO modification, DFT calculations showed a decrease of Mulliken atomic charge for the olefinic carbons pointing to a lower reactivity. For UV cured nano/microhybrid composites, a significant improvement of abrasion resistance was obtained.

  13. Lower-curing-temperature PMR polyimides

    NASA Technical Reports Server (NTRS)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

    1981-01-01

    Studies were performed to achieve a lower-curing-temperature PMR polyimide. The use of m-aminostyrene as the end-cap instead of the monoalkyl ester of 5-normbornene-2,3 dicarboxylic acid was investigated in typical PMR formulations. Model compound studies were also performed. Differential scanning calorimetry studies were performed on model compounds and neat resins to establish their melting and curing characteristics. The elevated temperature weight loss characteristics of neat resins and graphite fiber composites were determined. The room temperature and short-time 260 C (500 F) mechanical properties of the composites were also determined. The use of m-aminostyrene end-caps reduced the final cure temperature of PMR resins by about 55 C (100 F), but the composites prepared with these resins are limited to use temperatures of about 260 C (500 F).

  14. The research of UV curing injection molding

    NASA Astrophysics Data System (ADS)

    Xie, Pengcheng; Chang, Le; Song, Le; Cai, Tianze; Ding, Yumei; Yang, Weimin

    2015-05-01

    The micro-injection molding technology and the UV (ultraviolet) curing technique are combined to bring about a new plastic forming method, UV curing injection molding. The mean weight of micro-product is an important process characteristic for UV curing injection molding as well as the surface quality of micro-features is another important process characteristic for this new plastic forming method. This research investigates three effects of processing factors on the mass-change rate of micro-product and the surface quality of micro-features. In every particular, the following two factors are considered: UV material system temperature and the packing pressure. The study revealed that as usual, the micro-products gain weight with the imported increasing UV material system temperature and the improved packing pressure. Meanwhile, the increasing packing pressure also improves the surface quality, yet, warming the UV system temperature up has no effect on the quality of the product.

  15. Outdoor durability of radiation-cured coatings

    SciTech Connect

    Holman, R.; Kennedy, R.

    1997-12-31

    Radiation cured coatings are used almost exclusively on products which have little or no exposure to moisture or the weather; inks, furniture varnishes, floor varnishes and coatings for electronic components. However there is considerable interest in being able to use this technology in exterior environments as a substitute for solvent-borne coatings. A 3-year study examining the possible reasons for the poor durability of radiation curable coatings showed that the resistance of the monomers and oligomers to hydrogen abstraction was crucially important, and the water permeability of the cured coating influenced the long-term adhesion performance. The project concluded that with the appropriate combination of curing technology and monomer/oligomer selection, the prospects of UV curable coatings for outdoor exposure are very encouraging.

  16. Cure-in-place process for seals

    DOEpatents

    Hirasuna, Alan R.

    1981-01-01

    A cure-in-place process which allows a rubber seal element to be deformed to its service configuration before it is cross-linked and, hence, is a plastic and does not build up internal stress as a result of the deformation. This provides maximum residual strength to resist the differential pressure. Furthermore, the process allows use of high modulus formulations of the rubber seal element which would otherwise crack if cured and then deformed to its service configuration, resulting in a seal which has better gap bridging capability. Basically, the process involves positioning an uncured seal element in place, deforming it to its service configuration, heating the seal element, curing it in place, and then fully seating the seal.

  17. Adhesive curing through low-voltage activation

    PubMed Central

    Ping, Jianfeng; Gao, Feng; Chen, Jian Lin; Webster, Richard D.; Steele, Terry W. J.

    2015-01-01

    Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives. PMID:26282730

  18. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  19. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  20. FTIR Monitoring Of Curing Of Composites

    NASA Technical Reports Server (NTRS)

    Druy, Mark A.; Stevenson, William A.; Young, Philip R.

    1990-01-01

    Infrared-sensing optical fiber system developed to monitor principal infrared absorption bands resulting from vibrations of atoms and molecules as chemical bonds form when resin cured. System monitors resin chemistry more directly. Used to obtain Fourier transform infrared (FTIR) spectrum from graphite fiber/polyimide matrix resin prepreg. Embedded fiber optic FTIR sensor used to indicate state of cure of thermosetting composite material. Developed primarily to improve quality of advanced composites, many additional potential applications exist because principal of operation applicable to all organic materials and most inorganic gases. Includes monitoring integrities of composite materials in service, remote sensing of hazardous materials, and examination of processes in industrial reactors and furnaces.

  1. [Light-cured glass ionomer cements].

    PubMed

    Nordbø, H

    1989-12-01

    An attempt at improving the properties of glass-ionomer cements is represented by the incorporation of light-cure resin systems. This produces materials which have mechanical properties and moisture sensitivity superior to those of present glass-ionomer cements. Such hybrid materials cure by two different mechanisms: polymerization and salt formation. In particular, the early mechanical properties and water sensitivity of the materials are improved due to the formation of a polymer matrix. The tendency to undergo surface crazing during desiccation is also reduced. Three commercially available products are shortly described. PMID:2640704

  2. Prevent and cure disuse bone loss

    NASA Technical Reports Server (NTRS)

    Jee, Webster S. S.

    1994-01-01

    Anabolic agents like parathyroid hormone and postagladin E-like substances were studied in dogs and rats to determine their effectiveness in the prevention and cure of bone loss due to immobilization. It was determined that postagladin E2 administration prevented immobilization while at the same time it added extra bone in a dose responsive manner. Although bone mass returns, poor trabecular architecture remains after normal ambulation recovery from immobilization. Disuse related bone loss and poor trabecular architecture were cured by post-immobilization postagladin E2 treatment.

  3. The effect of curing modes on polymerization contraction stress of a dual cured composite.

    PubMed

    Feng, L; Suh, B I

    2006-01-01

    Although a lower curing rate is often cited as the reason why a chemical cured (CC) dental composite produces lower polymerization contraction stress (PCS) than a light cured (LC) composite, the exact mechanism is still unclear. In addition, the comparison is often made by using different brands of composites. The comparison's fairness is questionable because the two composites have different compositions and preparation procedures. The goal of the present work was to determine if the curing mode alone can produce different PCS. We formulated a dual cured composite and prepared it the same way for both CC and LC modes. We measured PCS by a strain gauge method, shrinkage by a video-imagining technique, degree of conversion (DC) by infrared spectroscopy, and flexural modulus by the three-point bending test. The CC specimens showed lower PCS and lower flexural modulus than the LC specimens, although both possessed an identical chemical composition and physical texture before cure. This finding indicates that the curing mode alone can affect PCS. Because the CC and LC specimens produced a similar shrinkage and DC, the lower modulus is considered to be one of the reasons for the lower stress. Using a structural inhomogeneity model, we explained how a resin composite with an identical DC can have different physical properties such as the modulus. PMID:16047326

  4. Thermal emission and curing efficiency of LED and halogen curing lights.

    PubMed

    Vandewalle, Kraig S; Roberts, Howard W; Tiba, Amer; Charlton, David G

    2005-01-01

    The purpose of this study was to compare the thermal emission and curing efficiency of LED (LEDemetron 1, SDS/Kerr) and QTH (VIP, BISCO) curing lights at maximum output and similar power, power density and energy density using the same light guide. Also, another LED curing light (Allegro, Den-Mat) and the QTH light at reduced power density were tested for comparison. Increase in temperature from the tips of the light guides was measured at 0 and 5 mm in air (23 degrees C) using a temperature probe (Fluke Corp). Pulpal temperature increase was measured using a digital thermometer (Omega Co) and a K-type thermocouple placed on the central pulpal roof of human molars with a Class I occlusal preparation. Measurements were made over 90 seconds with an initial light activation of 40 seconds. To test curing efficiency, resin composites (Z100, A110, 3M/ESPE) were placed in a 2-mm deep and 8-mm wide plastic mold and cured with the LED and QTH curing lights at 1- and 5-mm curing distances. Knoop Hardness Numbers (KHN) were determiped on the top and bottom surfaces (Leco). Bottom hardness values were expressed as a percentage of maximum top hardness. No significant differences were found in maximum thermal emission or KHN ratios between the LED (LEDemetron 1) and the QTH (VIP) at maximum output and similar energy densities (ANOVA/Tukey's; alpha=0.05). PMID:15853113

  5. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  6. NASA Hydrogen Peroxide Propellant Hazards Technical Manual

    NASA Technical Reports Server (NTRS)

    Baker, David L.; Greene, Ben; Frazier, Wayne

    2005-01-01

    The Fire, Explosion, Compatibility and Safety Hazards of Hydrogen Peroxide NASA technical manual was developed at the NASA Johnson Space Center White Sands Test Facility. NASA Technical Memorandum TM-2004-213151 covers topics concerning high concentration hydrogen peroxide including fire and explosion hazards, material and fluid reactivity, materials selection information, personnel and environmental hazards, physical and chemical properties, analytical spectroscopy, specifications, analytical methods, and material compatibility data. A summary of hydrogen peroxide-related accidents, incidents, dose calls, mishaps and lessons learned is included. The manual draws from art extensive literature base and includes recent applicable regulatory compliance documentation. The manual may be obtained by United States government agencies from NASA Johnson Space Center and used as a reference source for hazards and safe handling of hydrogen peroxide.

  7. 21 CFR 184.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... vinegar Amount sufficient for the purpose Remove sulfur dioxide from wine prior to fermentation to produce vinegar. Emulsifiers containing fatty acid esters 1.25 Bleaching agent. (d) Residual hydrogen peroxide...

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

    PubMed

    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. PMID:26635279

  9. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

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

    PubMed Central

    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 O2-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 O2, 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. PMID:23457415

  11. ESR study of MMA polymerization by a peroxide/amine system: bone cement formation.

    PubMed

    Oldfield, F F; Yasuda, H K

    1999-03-15

    Electron spin resonance (ESR) spectroscopy was used to gain insight at the molecular level into the curing of bone cement. Methyl methacrylate was polymerized using a N,N-dimethyl-p-toluidine (TD)/benzoyl peroxide (BPO) redox system in the presence of polymethyl methacrylate (PMMA) powder. The conventional nine-line ESR spectrum for the growing polymer radical was detected at the gel stage of polymerization. While the optimum free radical concentration was observed near the equimolar amine/BPO concentration, excess amine led to a change in the chemical structure of the trapped radical and inhibited the polymerization process. At a high amine/BPO ratio the nine-line signal disappeared and a three-line nitroxide-based radical appeared. The appearance of this nitroxide signal seems to depend on the amine/BPO molar ratio and on the presence of PMMA. An excess amount of amine with respect to BPO was found to inhibit the polymerization process. When BPO was removed, the system still polymerized but with a longer gelation time and a lower radical concentration. These results demonstrate that trapped free radicals in the bulk polymerization of MMA convert to polymeric peroxides that act as initiators in bone cement. When the accelerator 4-dimethylamino phenethyl alcohol (TDOH) was used, a higher radical concentration was observed in the polymerizing system. TDOH shows potential for being a more effective accelerator than TD for bone cement curing. PMID:10397948

  12. Resin Characterization in Cured Composite Materials

    NASA Technical Reports Server (NTRS)

    Young, P. R.; Chang, A.

    1985-01-01

    Molecular-level characterization of polymeric matrix resin in cured graphite-reinforced composite materials now determined through analysis of diffuse reflectance (DR) with Fourier Transform Infrared (FTIR) spectroscopy. Improved analytical method based on diffuse reflectance. DR/ FTIR technique successfully applied to analysis of several different composites and adhesives impossible to analyze by conventional methods.

  13. Cure-rate data for silicone adhesive

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C.; Fisher, A.

    1978-01-01

    Report describes work with concentrations down to 0.07 percent and is useful when applying adhesives in terrestrial and space applications. Cured Silicone retains low-outgassing properties as well as its snap, elongation, and resilience. Tests for hardness of silicone material also showed good results. No gross hysteresis observable on recovery from stretching nor was there any decrease in hardness.

  14. Campus Violence: Kinds, Causes, and Cures.

    ERIC Educational Resources Information Center

    Whitaker, Leighton C., Ed.; Pollard, Jeffrey W., Ed.

    This volume offers 14 papers on the types, sources, and possible cures of violence on college campuses from prominent workers in higher education. Following a preface the titles are: (1) "Conceptualizing Campus Violence: Definitions, Underlying Factors, and Effects" by Mary L. Roark; (2) "Administrative Perspectives on Disruptive Student Conduct"…

  15. Adhesive curing options for photonic packaging

    NASA Astrophysics Data System (ADS)

    Martin, Steven C.; Hubert, Manfred; Tam, Robin

    2002-06-01

    Varying the intensity of illumination used to cure photoactivated adhesives has been applied in medical and dental applications to improve the performance of polymer materials. For example, it has been observed that dental polymer composite materials express reduced shrinkage, important for durability of non-amalgam restorations, by introducing a phased time-intensity cure schedule. This work identified that curing conditions could influence the final properties of materials, and suggested the possibility of extending the characteristics that could be influenced beyond shrinkage to humidity resistance, Tg, outgassing and other important material properties. Obviously, these results have important ramifications for the photonic industry, with current efforts focused on improved manufacturing techniques. Improvement in low cost packaging solutions, including adhesives, will have to be made to bring the component cost down to address the needs of Metro and similar markets. However, there are perceived problems with the widespread use of adhesives, the most prevalent of these involving long term durability of the bond. Devices are typically aligned to sub-micron precision using active feedback and then must be locked in position to maintain performance. In contrast to traditional fastening methods, adhesive bonding is a highly attractive option due to the ease of deployment, lower equipment costs, and improved flexibility. Moreover, using methods analogous to those employed in dental applications, materials properties of photonic adhesives may be tailored using a programmed cure approach.

  16. Finally: A Cure for the Skills Gap.

    ERIC Educational Resources Information Center

    Rauschenberger, John

    2001-01-01

    The Manufacturing Skill Standards Council was established to create a system of skill standards, assessments, and certification designed to ensure a qualified, mobile work force to meet the needs of the economy in the 21st century. The system would provide a long-term cure for the skills gap confronting manufacturers. (JOW)

  17. Lipid Peroxidation by Human Blood Phagocytes

    PubMed Central

    Stossel, Thomas P.; Mason, Robert J.; Smith, Arnold L.

    1974-01-01

    Cell suspensions enriched in human blood monocytes, obtained from normal peripheral blood by sedimentation on sodium diatrizoate-Ficoll gradients or from the blood of patients with neutropenia and monocytosis, accumulated malonyldialdehyde, a labile catabolite of lipid peroxidation, during incubations with polystyrene beads or heat-killed Staphylococcus epidermidis. Mixed blood leukocytes principally composed of granulocytes or granulocytes purified by density gradient sedimentation did not accumulate malonyldialdehyde during incubations with these particles, but did when ingesting particles containing linolenate. The phospholipid fatty acid composition of monocyte-enriched and purified granulocyte preparations from the same donors were compared. The molar fraction of arachidonate (20:4) in phospholipids from monocyte-rich preparations was 62% greater than that of purified granulocytes. The findings indicate that human monocytes, possibly because of a greater content of polyunsaturated fatty acids in their membranes, peroxidize a greater quantity of endogenous lipids than granulocytes during endocytosis. Normal human granulocytes have the capacity to peroxidize ingested lipids. However, mixed leukocytes from two patients with chronic granulomatous disease produced little malonyldialdehyde when engulfing linolenate-containing particles. Therefore the capacity to peroxidize lipid is related to cellular oxygen metabolism, a function in which chronic granulomatous disease granulocytes are dificient. Malonyldialdehyde chemically prepared by hydrolysis of tetramethoxypropane, by extraction from peroxidized linolenic acid, or purified from extracts of phagocytizing rabbit alveolar macrophages had bactericidal activity against Escherichia coli and S. epidermidis. Therefore, toxic catabolites of lipid hydroperoxides may potentiate the bactericidal activity of hydrogen peroxide in mononuclear phagocytes. PMID:4853010

  18. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    SciTech Connect

    HALGREN DL

    2008-07-30

    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.

  19. Antibiotics Cure Anthrax in Animal Models▿

    PubMed Central

    Weiss, Shay; Kobiler, David; Levy, Haim; Pass, Avi; Ophir, Yakir; Rothschild, Nili; Tal, Arnon; Schlomovitz, Josef; Altboum, Zeev

    2011-01-01

    Respiratory anthrax, in the absence of early antibiotic treatment, is a fatal disease. This study aimed to test the efficiency of antibiotic therapy in curing infected animals and those sick with anthrax. Postexposure prophylaxis (24 h postinfection [p.i.]) of guinea pigs infected intranasally with Bacillus anthracis Vollum spores with doxycycline, ofloxacin, imipenem, and gentamicin conferred protection. However, upon termination of treatment, the animals died from respiratory anthrax. Combined treatment with antibiotics and active vaccination with a protective antigen-based vaccine leads to full protection even after cessation of treatment. Delaying the initiation of antibiotic administration to over 24 h p.i. resulted in treatment of animals with anthrax exhibiting various degrees of bacteremia and toxemia. Treatment with doxycycline or ciprofloxacin cured sick guinea pigs and rabbits exhibiting bacteremia levels up to 105 CFU/ml. Addition of anti-protective antigen (PA) antibodies augmented the efficiency of protection, allowing the cure of guinea pigs and rabbits with 10- to 20-fold-higher bacteremia levels, up to 7 × 105 CFU/ml and 2 × 106 CFU/ml, respectively. Treatment with ciprofloxacin and a monoclonal anti-PA antibody rescued rabbits with bacteremia levels up to 4 × 106 CFU/ml. During antibiotic administration, all surviving animals developed a protective immune response against development of a fatal disease and subcutaneous challenge with Vollum spores. In conclusion, these results demonstrate that antibiotic treatment can prevent the development of fatal disease in respiratory-anthrax-infected animals and can cure animals after disease establishment. A therapeutic time window of 40 h to 48 h from infection to initiation of efficient antibiotic-mediated cure was observed. PMID:21263056

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

    DOEpatents

    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.

  1. Characterization of the relationship of the cure cycle chemistry to cure cycle processing properties

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.

    1985-01-01

    Dynamic dielectric analysis (DDA) is used to study curing polymer systems and thermoplastics. Measurements are made over a frequency range of six decades. This wide range of frequencies increases the amount of information which can be obtained. The data is analyzed in terms of the frequency dependence of the complex permittivity epsilon sup *, specific conductivity sigma (ohm/cm) and the relaxation time tau, parameters which are characteristic of the cure state of the material and independent of the size of the sample.

  2. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  3. A Study of Upgraded Phenolic Curing for RSRM Nozzle Rings

    NASA Technical Reports Server (NTRS)

    Smartt, Ziba

    2000-01-01

    A thermochemical cure model for predicting temperature and degree of cure profiles in curing phenolic parts was developed, validated and refined over several years. The model supports optimization of cure cycles and allows input of properties based upon the types of material and the process by which these materials are used to make nozzle components. The model has been refined to use sophisticated computer graphics to demonstrate the changes in temperature and degree of cure during the curing process. The effort discussed in the paper will be the conversion from an outdated solid modeling input program and SINDA analysis code to an integrated solid modeling and analysis package (I-DEAS solid model and TMG). Also discussed will be the incorporation of updated material properties obtained during full scale curing tests into the cure models and the results for all the Reusable Solid Rocket Motor (RSRM) nozzle rings.

  4. Cationic cure kinetics of a polyoxometalate loaded epoxy nanocomposite

    SciTech Connect

    Anderson, Benjamin J.

    2012-08-06

    The reaction cure kinetics of a novel polyoxometalate (POM) loaded epoxy nanocomposite is described. The POM is dispersed in the epoxy resin up to volume fractions of 0.1. Differential scanning calorimetry measurements show the cure of the epoxy resin to be sensitive to the POM loading. A kinetics study of the cure exotherm confirms that POM acts as a catalyst promoting cationic homopolymerization of the epoxy resin. The cure reaction is shown to propagate through two cure regimes. A fast cure at short time is shown to be propagation by the activated chain end (ACE) mechanism. A slow cure at long time is shown to be propagation by the activated monomer (AM) mechanism. The activation energies for the fast and slow cure regimes agree well with other epoxy based systems that have been confirmed to propagate by the ACE and AM mechanisms.

  5. Curing chemistry of phenylethynyl-terminated imide oligomers: Model compounds, carbon-13 labeling and cure analysis

    NASA Astrophysics Data System (ADS)

    Roberts, Christopher Chad

    1998-11-01

    Phenylethynyl-terminated imide oligomers (PETI) are currently considered the state-of-the-art high performance resins for aerospace applications. The processing of these resins is more facile because of their low molecular weight, but PETI's cure to form a tough, solvent-resistant material. However, the final cure structure was a complete mystery. Hence, the present study was set forth with three essential goals. The determination of the final structure of the crosslinked polymer is of obvious importance. Second, the crosslinking mechanism and controlling factors is also of interest. Lastly, the final structure of the crosslinked polymers was correlated with mechanical and thermal properties, thereby helping to establish the structure-processing-properties relationships for PETI resins. These goals were accomplished by using a combination of synthesis of model compounds synthesis and proposed cure products, sp{13}C labeling of the ethynyl endgroup in PETI's, monitoring of the thermal cure using solid state sp{13}C NMR and ESR and molecular modeling techniques. Phenylethynyl endcapping agents, 4-(phenylethynyl)phthalic anhydride (PEPA) and 3-(phenylethynyl)aniline (3PEA), were synthesized via the palladium-catalyzed coupling of phenylacetylene with 4-bromophthalic anhydride or 3-iodonitrobenzene followed by reduction to 3PEA, respectively. Isolated yields of 41 and 86% for 3PEA and PEPA were obtained, respectively. Model compounds were synthesized from 3PEA and PEPA by reacting with them the appropriate aniline or phthalic anhydride derivative. Model compounds included N-pentafluorophenyl-4-(phenylethynyl)phthalimide (PEPA/F5An), N-(4-trifluoromethyl-phenyl)4-(phenylethynyl)phthalimide (PEPA/F3CAn), N-lbrack 3-(phenylethynyl)phenylrbrack\\ phthalimide (3PEA/PA), N-phenyl-4-(phenylethynyl)phthalimide (PEPA/An), N-(4-phenoxyphenyl)4-(phenylethynyl)phthalimide (PEPA/POAn), and N-(1-naphthyl)-4-(phenylethynyl)phthalimide (PEPA/Anaph). Proposed cure products such as

  6. New type of measuring and intelligent instrument for curing tobacco

    NASA Astrophysics Data System (ADS)

    Yi, Chui-Jie; Huang, Xieqing; Chen, Tianning; Xia, Hong

    1993-09-01

    A new type of measuring intelligent instrument for cured tobacco is presented in this paper. Based on fuzzy linguistic control principles the instrument is used to controlling the temperature and humidity during cured tobacco taking 803 1 singlechip computer as a center controller. By using methods of fuzzy weighted factors the cross coupling in curing procedures is decoupled. Results that the instrument has producted indicate the fuzzy controller in the instrument has perfect performance for process of cured tobacco as shown in figure

  7. Silicone rubber curing by high intensity infrared radiation

    SciTech Connect

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

    1994-08-10

    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} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

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

    SciTech Connect

    Janke, C. J.; Howell, Dave; Norris, Robert E.

    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.

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

    SciTech Connect

    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.

  10. [Hydrogen peroxide in artificial photosynthesizing systems].

    PubMed

    Lobanov, A V; Komissarov, G G

    2014-01-01

    From the point of view of the concepts of hydrogen peroxide as a source of photosynthetic oxygen (hydrogen) coordination and photochemical properties of chlorophyll and its aggregates towards hydrogen peroxide were considered. The binding energy of H2O and H2O2 with chlorophyll and chlorophyllide depending on their form (monomers, dimers and trimers) was estimated by quantum chemical calculations. It is shown that at an increase of the degree of the pigment aggregation binding energy of H2O2 was more than the energy of H2O. Analysis of experimental results of the photochemical decomposition of hydrogen peroxide using chlorophyll was carried out. Estimates of the thermodynamic parameters (deltaG degrees and deltaH degrees) of the formation of organic compounds from CO2 with water and hydrogen peroxide were compared. The interaction of CO2 with H2O2 requires much less energy consumption than with water for all considered cases. The formation of organic products (formaldehyde, alcohols, carboxylic and carbonylic compounds) and simultaneous production of O2 under the influence of visible light in the systems of inorganic carbon--hydrogen peroxide--chlorophyll (phthalocyanine) is detected by GC/MS method, FTIR spectroscopy, and chemical analysis. PMID:25702472

  11. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    PubMed Central

    Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products. PMID:24260736

  12. Improved cure method for single component silicone rubber

    NASA Technical Reports Server (NTRS)

    Lippitt, M. W.

    1969-01-01

    Water is incorporated in a carrier and then thoroughly mixed with the single component silicone rubber containing acetic anhydride as a curing agent. Because curing occurs with the water supplied internally, controlled curing is possible within a reasonable period of time, regardless of the thickness of the material.

  13. Lipid peroxide formation in microsomes. Relationship of hydroxylation to lipid peroxide formation

    PubMed Central

    Wills, E. D.

    1969-01-01

    1. Aminopyrine strongly inhibits NADPH-induced lipid peroxide formation in rat liver microsomes, but ascorbate-induced peroxidation is inhibited to a smaller extent. 2. Aminopyrine oxidation is stimulated by Mg2+ but inhibited by Ca2+. Concentrated solutions (10mm) of iron-chelating agents inhibit aminopyrine oxidation, but the more dilute solutions (0·5mm) of chelators that block lipid peroxide formation do not inhibit aminopyrine oxidation. Microsomes prepared from sucrose–EDTA homogenates rapidly oxidize aminopyrine, but do not form lipid peroxide when incubated with ascorbate or NADPH. 3. Aminopyrine oxidation is strongly inhibited by p-chloromercuribenzoate, less by iodoacetamide and weakly by N-ethylmaleimide. The site of action of these compounds is considered to be a ferredoxin-type protein. GSH and cysteine also inhibit. 4. Other drugs oxidized by microsomes such as caffeine, phenobarbitone and hexobarbitone had either no or little effect on lipid peroxide formation, but codeine inhibited. 5. Most aliphatic hydrocarbons, alcohols, ketones and aldehydes did not affect lipid peroxide formation, but chloroform and carbon tetrachloride inhibited. 6. Many aromatic compounds inhibited lipid peroxide formation. Only aromatic acids were without any effect and phenols and amines were very strong inhibitors. 7. Induction of lipid peroxide formation in microsomes by incubation with ascorbate or NADPH or by treatment with ionizing radiation leads to a sharp decline in the ability of microsomes to oxidize aminopyrine or hydroxylate aniline. 8. It is considered that the two processes of hydroxylation and lipid peroxide formation are closely linked in microsomes. They probably depend on the same electron-transport chain, and peroxide formation, which involves membrane disintegration, may be part of the normal membrane remodelling process. PMID:4390103

  14. Light-Curing Adhesive Repair Tapes

    NASA Technical Reports Server (NTRS)

    Allred, Ronald; Haight, Andrea Hoyt

    2009-01-01

    Adhesive tapes, the adhesive resins of which can be cured (and thereby rigidized) by exposure to ultraviolet and/or visible light, are being developed as repair patch materials. The tapes, including their resin components, consist entirely of solid, low-outgassing, nonhazardous or minimally hazardous materials. They can be used in air or in vacuum and can be cured rapidly, even at temperatures as low as -20 C. Although these tapes were originally intended for use in repairing structures in outer space, they can also be used on Earth for quickly repairing a wide variety of structures. They can be expected to be especially useful in situations in which it is necessary to rigidize tapes after wrapping them around or pressing them onto the parts to be repaired.

  15. Contactless optoelectronic technique for monitoring epoxy cure.

    PubMed

    Cusano, A; Buonocore, V; Breglio, G; Calabrò, A; Giordano, M; Cutolo, A; Nicolais, L

    2000-03-01

    We describe a novel noninvasive optical technique to monitor the refractive-index variation in an epoxy-based resin that is due to the polymerization process. This kind of resin is widely used in polymer matrix composites. It is well known that the process of fabricating a thermoset-based composite involves mass and heat transfer coupled with irreversible chemical reactions that induce physical changes. To improve the quality and the reliability of these materials, monitoring the cure and optimization of the manufacturing process are of key importance. We discuss the basic operating principles of an optical system based on angle deflection measurements and present typical cure-monitoring results obtained from optical characterization. The method provides a flexible, high-sensitivity, material-independent, low-cost, noninvasive tool for monitoring real-time refractive-index variation. PMID:18337994

  16. UV curing with water based materials

    SciTech Connect

    Beck, E.; Haeussling, L.; Jaeger, U.

    1995-12-01

    Conventional coatings technology requires a large effort to reduce emissions of organic solvents and other volatile organic components. Alleviations, yet not a solution to this problem are high solids coatings formulations or even powder coatings technology. An entirely different concept is used in radiation curing of coatings, where all the elements of the originally low molar mass components of the coating formulation are polymerized into one large network. Thus there should be no emissions of low molar mass compounds from UV- or Electron beam cured films. Water as a diluent in UV-curable formulations can either be used directly as a solvent or in emulsions (with the help of emulsifying agents) without a loss in performance of coatings properties, such as hardness, elasticity and reactivity. To the contrary, the prearrangement of functionalities in the final coating due to the prior phase separation in the emulsion seems to slightly increase hardness and adhesion as well as elasticity.

  17. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1995-03-07

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of ``standard`` polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  18. Aloe vera as cure for lichen planus.

    PubMed

    Patil, Bharati A; Bhaskar, Hebbar Pragati; Pol, Jyoti S; Sodhi, Amandeep; Madhu, Asha V

    2013-01-01

    Oral lichen planus is a difficult condition to treat because of its chronic nature. Various treatment modalities have resulted in partial regression of symptoms but not a complete cure. Aloe vera, a product with minimal adverse effects, can be tried to treat this disorder. A 38-year-old male patient diagnosed with lichen planus of the skin and the oral mucosa was suffering from severe pain and a burning sensation intraorally and pruritus of the skin lesions. Considering the extensive involvement, an herbal alternative was considered. The patient was prescribed aloe vera juice and gel application for two months. At the nine-month follow-up, the patient was symptom-free and totally cured of the intraoral and skin lesions. PMID:24245466

  19. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1993-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  20. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, John D.

    1995-01-01

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of "standard" polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal or oxide may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  1. Vacuum deposition and curing of liquid monomers

    DOEpatents

    Affinito, J.D.

    1993-11-09

    The present invention is the formation of solid polymer layers under vacuum. More specifically, the present invention is the use of standard polymer layer-making equipment that is generally used in an atmospheric environment in a vacuum, and degassing the monomer material prior to injection into the vacuum. Additional layers of polymer or metal may be vacuum deposited onto solid polymer layers. Formation of polymer layers under a vacuum improves material and surface characteristics, and subsequent quality of bonding to additional layers. Further advantages include use of less to no photoinitiator for curing, faster curing, fewer impurities in the polymer electrolyte, as well as improvement in material properties including no trapped gas resulting in greater density, and reduced monomer wetting angle that facilitates spreading of the monomer and provides a smoother finished surface.

  2. Using Sex to Cure the Genome

    PubMed Central

    Rocha, Eduardo P. C.

    2016-01-01

    The diversification of prokaryotes is accelerated by their ability to acquire DNA from other genomes. However, the underlying processes also facilitate genome infection by costly mobile genetic elements. The discovery that cells can uptake DNA by natural transformation was instrumental to the birth of molecular biology nearly a century ago. Surprisingly, a new study shows that this mechanism could efficiently cure the genome of mobile elements acquired through previous sexual exchanges. PMID:26987049

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

    MedlinePlus

    ... Small Business Programs Activities and opportunities geared toward small businesses Peer Review Review of the scientific & technical merit of grant applications Contacts for NICHD Funding Information ... It also is possible that a person cured of Cushing’s disease might not recover their previous mental strength, including memory, but any functional difference is usually small. 4 , 5 People whose Cushing’s syndrome was caused ...

  4. Improved Cure-in-Place Silicone Adhesives

    NASA Technical Reports Server (NTRS)

    Blevins, C. E.; Sweet, J.; Gonzalez, R.

    1982-01-01

    Two improved cure-in-place silicone-elastomer-based adhesives have low thermal expansion and low thermal conductivity. Adhesives are flexible at low temperature and withstand high temperatures without disintegrating. New ablative compounds were initially developed for in-flight repair of insulating tile on Space Shuttle orbiter. Could find use in other applications requiring high-performance adhesives, such as sealants for solar collectors.

  5. Photothermal Monitoring Of Curing Of Polymers

    NASA Technical Reports Server (NTRS)

    Rooney, Michael

    1993-01-01

    Time-resolved infrared radiometry (TRIR) adapted to monitoring curing of some polymers in production. Proposal part of continuing effort to perfect production of hydroxy-terminated polybutadiene for use in liners of solid-fuel rocket motors. Applicable to monitoring changing states of many other materials in process. TRIR, non-contact technique implemented with remotely situated equipment and better suited to use in production.

  6. Coating and curing apparatus and methods

    DOEpatents

    Brophy, Brenor L.; Gonsalves, Peter R.; Maghsoodi, Sina; Colson, Thomas E.; Yang, Yu S.; Abrams, Ze'ev R.

    2016-04-19

    Disclosed is a 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 curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

  7. Coating and curing apparatus and methods

    DOEpatents

    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.

  8. Hydrogen Peroxide - Material Compatibility Studied by Microcalorimetry

    NASA Technical Reports Server (NTRS)

    Homung, Steven D.; Davis, Dennis D.; Baker, David; Popp, Christopher G.

    2003-01-01

    Environmental and toxicity concerns with current hypergolic propellants have led to a renewed interest in propellant grade hydrogen peroxide (HP) for propellant applications. Storability and stability has always been an issue with HP. Contamination or contact of HP with metallic surfaces may cause decomposition, which can result in the evolution of heat and gas leading to increased pressure or thermal hazards. The NASA Johnson Space Center White Sands Test Facility has developed a technique to monitor the decompositions of hydrogen peroxide at temperatures ranging from 25 to 60 C. Using isothermal microcalorimetry we have measured decomposition rates at the picomole/s/g level showing the catalytic effects of materials of construction. In this paper we will present the results of testing with Class 1 and 2 materials in 90 percent hydrogen peroxide.

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

    PubMed

    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. PMID:25256505

  10. Hybrid Lanthanide-Actinide Peroxide Cage Clusters.

    PubMed

    Sigmon, Ginger E; Szymanowski, Jennifer E S; Carter, Korey P; Cahill, Christopher L; Burns, Peter C

    2016-03-21

    A cage cluster consisting of 31 uranyl and 9 Sm(3+) polyhedra self-assembles in an alkaline aqueous peroxide solution and crystallizes (U31Sm9). Trimers of Sm(3+) polyhedra are templated by μ3-η(2):η(2):η(2)-peroxide groups and link to oxo atoms of uranyl ions. Three such trimers link into a ring through uranyl hexagonal bipyramids, and these are attached through six polyhedra to a unit consisting of 21 uranyl hexagonal bipyramids to complete the cage. Luminescence spectra collected with an excitation wavelength of 420 nm reveal fine structure, which is not observed for a cluster containing only uranyl polyhedra. PMID:26923457

  11. Microhardness and Young's modulus of a bonding resin cured with different curing units.

    PubMed

    Yamauti, Monica; Nikaido, Toru; Ikeda, Masaomi; Otsuki, Masayuki; Tagami, Junji

    2004-12-01

    This study evaluated the microhardness and Young's modulus of a photocurable bonding resin, Clearfil SE Bond (SE), cured with four curing units at different distances. The curing units used were: Candelux (Quartz-tungsten halogen), Lux-O-Max (Blue light emitting diode), Arc-light (Plasma-arc), and Rayblaze (Metal halide). Discs of bonding resin were prepared using vinyl molds and were photocured at the top surface with light tip at three different distances (contact, 2 and 4 mm). After 24 hours of storage in water at 37 degrees C, the specimens were sectioned into halves, embedded in epoxy resin, and polished. The microhardness and Young's modulus of this bonding resin were measured using a nanoindentation tester. Six specimens were prepared for each group. The data was statistically analyzed using two-way ANOVA test and Tukey multiple comparison test (p < 0.01). The microhardness of SE was affected by light source and distance, as was Young's modulus. Candelux and Rayblaze presented the highest hardness and Young's modulus results. Both properties presented high values when the curing unit tip was maintained in contact with the irradiated surface. Increasing the distance between the curing unit tip and the irradiated surface decreased the hardness and Young's modulus of SE. PMID:15688707

  12. Characterization of the relationship of the cure cycle chemistry to cure cycle processing properties

    NASA Technical Reports Server (NTRS)

    Kranbuehl, D. E.

    1986-01-01

    Dynamic Dielectric measurements made over a wide range of frequency provide a sensitive and convenient means for monitoring the cure process in thermosets and thermoplastics. The measurement of dielectric relaxation is one of only a few instrumental techniques available for studying molecular properties in both the liquid and solid states. Furthermore, it is probably the only convenient experimental technique for studying the polymerization process of going from a monomeric liquid of varying viscosity to a crosslinked, insoluble, high temperature solid. The objective of the research is to develop on-line dielectric instrumentation for quantitative nondestructive material evaluation and closed loop smart cure cycle control. The key is to relate the chemistry of the cure cycle process to the dielectric properties of the polymer system by correlating the time, temperature, and frequency dependent dielectric measurements with chemical characterization measurements. Measurement of the wide variation in magnitude of the complex permittivity with both frequency and state of cure, coupled with chemical characterization work, have been shown in the laboratory to have the potential to determine: resin quality, composition and age; cure cycle window boundaries; onset of flow and point of maximum flow; extent of and completion of reaction; evolution of volatiles; T sub g; and, crosslinking and molecular weight buildup.

  13. Effect of electron water curing and electron charging curing on concrete strength

    SciTech Connect

    Yu, Q.; Sugita, S.; Sawayama, K.; Isojima, Y.

    1998-09-01

    By charging normal water under an appropriate electric voltage, electron water can be produced. With its small molecule cluster and high activity, the water has been found to have applications in many fields. This study showed that: (1) by curing concrete specimens in electron water, concrete strength was increased by at least 5% and by more than 15% at early ages in comparison to that of the concrete cured in normal water at the same temperature; and (2) by electron charging curing the strength of concrete could also be improved, especially its 1-day strength, which was increased by as high as 50% relative to that of control specimens. The possible reason for the strength increase of concrete by both curing methods is that the curing water and the water in concrete both have small molecule clusters and high activity caused by the charging treatment, resulting in the improvement on cement hydration and the decrease in average pore size and the volumes of large pores of concrete.

  14. SureCure ®-A new material to reduces curing time and improve curing reproducibility of lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Boden, David P.; Loosemore, Daniel V.; Botts, G. Dean

    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 1 wt.% of leady oxide with finely-divided tetrabasic lead sulfate (SureCure™ 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.

  15. Argon Ion Laser Polymerized Acrylic Resin: A Comparative Analysis of Mechanical Properties of Laser Cured, Light Cured and Heat Cured Denture Base Resins

    PubMed Central

    Murthy, S Srinivasa; Murthy, Gargi S

    2015-01-01

    Background: Dentistry in general and prosthodontics in particular is evolving at greater pace, but the denture base resins poly methyl methacrylate. There has been vast development in modifying chemically and the polymerization techniques for better manipulation and enhancement of mechanical properties. One such invention was introduction of visible light cure (VLC) denture base resin. Argon ion lasers have been used extensively in dentistry, studies has shown that it can polymerize restorative composite resins. Since composite resin and VLC resin share the same photo initiator, Argon laser is tested as activator for polymerizing VLC resin. In the Phase 1 study, the VLC resin was evaluated for exposure time for optimum polymerization using argon ion laser and in Phase 2; flexural strength, impact strength, surface hardness and surface characteristics of laser cured resin was compared with light cure and conventional heat cure resin. Materials and Methods: Phase 1; In compliance with American Dental Association (ADA) specification no. 12, 80 samples were prepared with 10 each for different curing time using argon laser and evaluated for flexural strength on three point bend test. Results were compared to established performance requirement specified. Phase 2, 10 specimen for each of the mechanical properties (30 specimen) were polymerized using laser, visible light and heat and compared. Surface and fractured surface of laser, light and heat cured resins were examined under scanning electron microscope (SEM). Results: In Phase 1, the specimen cured for 7, 8, 9 and 10 min fulfilled ADA requirement. 8 min was taken as suitable curing time for laser curing. Phase 2 the values of mechanical properties were computed and subjected to statistical analysis using one-way ANOVA and Tukey post-hoc test. The means of three independent groups showed significant differences between any two groups (P < 0.001). Conclusion: Triad VLC resin can be polymerized by argon ion laser with

  16. Chemical analysis of electron beam curing of positive photoresist

    NASA Astrophysics Data System (ADS)

    Ross, Matthew F.; Christensen, Lorna D.; Magvas, John

    1994-05-01

    In this paper the chemical and thermal properties of electron beam cured photoresist were investigated and compared with conventional thermal curing methods. The photoresist used in this investigation was AZ P.4620, a positive novolak based photoresist formulated for thick film applications. The films were exposed with varying dosages using an electron beam photoresist curing system. The photoresist films were then analyzed for residual solvent content, photoactive compound decomposition, percentage of crosslinking, and film shrinkage as a function of exposure dose. These properties were then compared with the properties of resist films cured using conventional thermal curing methods. A model of photoresist curing chemistry as a function of dose is proposed as well as a method for optimizing the cure of the photoresist for different applications.

  17. Self-Assembly of Uranyl-Peroxide Nanocapsules in Basic Peroxidic Environments.

    PubMed

    Miró, Pere; Vlaisavljevich, Bess; Gil, Adria; Burns, Peter C; Nyman, May; Bo, Carles

    2016-06-13

    A wide range of uranyl-peroxide nanocapsules have been synthesized using very simple reactants in basic media; however, little is known about the process to form these species. We have performed a density functional theory study of the speciation of the uranyl ions under different experimental conditions and explored the formation of dimeric species via a ligand exchange mechanism. We shed some light onto the importance of the excess of peroxide and alkali counterions as a thermodynamic driving force towards the formation of larger uranyl-peroxide species. PMID:27165671

  18. Modeling the curing process of thick-section autoclave cured composites

    NASA Technical Reports Server (NTRS)

    Loos, A. C.; Dara, P. H.

    1985-01-01

    Temperature gradients are significant during cure of large area, thick-section composites. Such temperature gradients result in nonuniformly cured parts with high void contents, poor ply compaction, and variations in the fiber/resin distribution. A model was developed to determine the temperature distribution in thick-section autoclave cured composites. Using the model, long with temperature measurements obtained from the thick-section composites, the effects of various processing parameters on the thermal response of the composites were examined. A one-dimensional heat transfer model was constructed for the composite-tool assembly. The governing differential equations and associated boundary conditions describing one-dimensional unsteady heat-conduction in the composite, tool plate, and pressure plate are given. Solution of the thermal model was obtained using an implicit finite difference technique.

  19. Cure shrinkage effects in epoxy and polycyanate matrix composites

    SciTech Connect

    Spellman, G.P.

    1995-12-22

    A relatively new advanced composite matrix, polycyanate ester, was evaluated for cure shrinkage. The chemical cure shrinkage of composites is difficult to model but a number of clever experimental techniques are available to the investigator. In this work the method of curing a prepreg layup on top of a previously cured laminate of identical ply composition is utilized. The polymeric matrices used in advanced composites have been primarily epoxies and therefore a common system of this type, Fiberite 3501-6, was used as a base case material. Three polycyanate matrix systems were selected for the study. These are: Fiberite 954-2A, YLA RS-3, and Bryte Technology BTCy-1. The first three of these systems were unidirectional prepreg with carbon fiber reinforcement. The Bryte Technology material was reinforced with E-glass fabric. The technique used to evaluate cure shrinkage results in distortion of the flatness of an otherwise symmetric laminate. The first laminate is cured in a conventional fashion. An identical layup is cured on this first laminate. During the second cure all constituents are exposed to the same thermal cycles. However, only the new portion of the laminate will experience volumetric changes associate with matrix cure. The additional strain of cure shrinkage results in an unsymmetric distribution of residual stresses and an associated warpage of the laminate. The baseline material, Fiberite 3501-6, exhibited cure shrinkage that was in accordance with expectations. Cure strains were {minus}4.5E-04. The YLA RS-3 material had cure strains somewhat lower at {minus}3.2E-04. The Fiberite 954-2A cure strain was {minus}1.5E-04 that is 70% lower than the baseline material. The glass fabric material with the Bryte BTCy-1 matrix did not result in meaningful results because the processing methods were not fully compatible with the material.

  20. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.356...

  1. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, R.; Randhava, S.S.; Tsai, S.P.

    1997-09-02

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H{sub 2}O{sub 2} laden permeate. 1 fig.

  2. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, Rathin; Randhava, Sarabjit S.; Tsai, Shih-Perng

    1997-01-01

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H.sub.2 O.sub.2 laden permeate.

  3. Electron beam curing of polymer matrix composites

    SciTech Connect

    Janke, C.J.; Wheeler, D.; Saunders, C.

    1998-01-08

    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.

  4. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  5. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  6. Crocidolite-induced lipid peroxidation. II. Role of antioxidants

    SciTech Connect

    Gulumian, M.; Kilroe-Smith, T.A.

    1987-12-01

    Asbestos fibers in vitro produce lipid peroxidation in rat lung microsomes. Butylated hydroxytoluene prevented this peroxidation. Ascorbate in low concentrations enhanced peroxidation of lipids but inhibited it at concentrations above 4 mmole/liter so that it partially protected membrane lipids from peroxidation produced by asbestos fibers. Reduced glutathione added to microsomes gave increased peroxidation at increased concentrations up to 20 mmol/liter. At 40 mmol/liter peroxidation was prevented. Glutathione had no obvious effect on the level of peroxidation produced by asbestos fibers. The 105,000g supernatant cell fraction added either with or without glutathione gave a decrease in the amount of lipid peroxidation produced by asbestos fibers. The protective action of these reducing agents suggests a possible use as prophylactic agents against the harmful effects of inhaled asbestos.

  7. Systems and methods for generation of hydrogen peroxide vapor

    DOEpatents

    Love, Adam H; Eckels, Joel Del; Vu, Alexander K; Alcaraz, Armando; Reynolds, John G

    2014-12-02

    A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above a hydrogen peroxide solution in the second container for producing a hydrogen peroxide vapor. A method according one embodiment includes at least one of bubbling dried air through a hydrogen peroxide solution in a container for producing a first hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above the hydrogen peroxide solution in a container for producing a second hydrogen peroxide vapor. Additional systems and methods are also presented.

  8. Dependence of curing time, peak temperature, and mechanical properties on the composition of bone cement.

    PubMed

    Brauer, G M; Steinberger, D R; Stansbury, J W

    1986-01-01

    Commercial bone cements usually contain hydroquinone as the polymerization inhibitor and N,N-dimethyl-p-toluidine as the accelerator in the benzoyl peroxide-initiated redox polymerization. The former compounds have certain shortcomings in their biocompatibility profile. Measurements of the setting times, polymerization exotherms, and postpolymerization strengths of the cured monomer-polymer compositions show that the hydroquinone can be replaced by food grade di-tert-butyl-p-cresol (BHT). The more reactive 4-N,N-(dimethylamino)phenethanol can replace 4-N,N-dimethyl-p-toluidine, yielding cements with shorter setting times and increased strengths. Excessive heat liberated on polymerization can be reduced by partial substitution of higher-molecular-weight methacrylates, e.g., dicyclopentenyloxyethyl methacrylate for methyl methacrylate, but there is a decrease in strength of the resulting polymer. More successful has been the addition to the monomer of 1% or 2% of the chain transfer agent pentaerythritol tetra(3-mercaptopropionate), which lowers the peak temperature without changing the physical properties of the cement. Compositions with short curing times, lower exotherms, and mechanical properties that exceed those of a commercial material have been formulated. PMID:3722218

  9. Lower-curing-temperature PMR polyimides

    NASA Technical Reports Server (NTRS)

    Delvigs, P.

    1982-01-01

    Partial substitution of a p-aminostyrene end-cap for the monomethyl ester of 5-norbornene-2, 3-dicarboxylic acid lowered the final cure temperature of typical PMR resins from 600 F to 500 F. The weight loss characteristics of neat resins and graphite fiber composites prepared by using the mixed end-cap approach were determined at 600 F. The room temperature and short-time elevated temperature mechanical properties of the composites at 550 F and 600 F were determined. The mechanical property retention characteristics of the composites at 550 F and 600 F are discussed.

  10. Reaction cured glass and glass coatings

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Leiser, D. B.; Katvala, V. W. (Inventor)

    1978-01-01

    The invention relates to reaction cured glass and glass coatings prepared by reacting a compound selected from the group consisting of silicon tetraboride, silicon hexaboride, other boron silicides, boron and mixtures with a reactive glass frit composed of a porous high silica borosilicate glass and boron oxide. The glassy composites of the present invention are useful as coatings on low density fibrous porous silica insulations used as heat shields and for articles such as reaction vessels that are subjected to high temperatures with rapid heating and cooling and that require resistance to temperature and repeated thermal shock at temperatures up to about 1482C (2700PF).