WorldWideScience

Sample records for alkali-silica reaction observed

  1. In situ alkali-silica reaction observed by x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kurtis, K.E.; Monteiro, P.J.M. [Univ. of California, Berkeley, CA (United States); Brown, J.T.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction.

  2. Effect of Mineral Admixtures on Alkali-Silica Reaction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chengzhi; WANG Aiqin

    2008-01-01

    The influence of silica fume,slag and fly ash on alkali-silica reaction under the condition of 70℃ is studied.The results show that silica,slag and fly ash may inhibit alkali-silica reaction only under suitable content.When the content is less than 10%,silica fume does not markedly influence the expansion of alkali-silica reaction.When the content is 15%-20%,silica fume only may delay the expansion of alkali-silica reaction.When the content is 30%-70%,slag may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is 10%,fly ash does not markedly influence the expansion of alkali-silica reaction.When the content is 20%-30%,fly ash may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is over 50%,it is possible that fly ash can inhibit effectively alkali-silica reaction.

  3. Effect of Pozzolanic Reaction Products on Alkali-silica Reaction

    Institute of Scientific and Technical Information of China (English)

    WEI Fengyan; LAN Xianghui; LV Yinong; XU Zhongzi

    2006-01-01

    The effect of fly ash on controlling alkali-silica reaction (ASR) in simulated alkali solution was studied. The expansion of mortar bars and the content of Ca(OH)2 in cement paste cured at 80 ℃ for 91 d were measured. Transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were employed to study the microstructure of C-S-H. TEM/energy dispersive spectroscopy (EDS) was then used to determine the composition of C-S-H. The pore structure of the paste was analyzed by mercury intrusion porosimetry (MIP). The results show that the contents of fly ash of 30% and 45% can well inhibit ASR. And the content of Ca(OH)2 decreases with the increase of fly ash. That fly ash reacted with Ca(OH)2 to produce C-S-H with a low Ca/Si molar ratio could bind more Na+ and K+ ions, and produce a reduction in the amount of soluble alkali available for ASR. At the same time, the C-S-H produced by pozzolanic reaction converted large pores to smaller ones (gel pores smaller than 10 nm) to densify the pore structure. Perhaps that could inhibit alkali transport to aggregate for ASR.

  4. Effect of Anti-freezing Admixtures on Alkali-silica Reaction in Mortars

    Institute of Scientific and Technical Information of China (English)

    LIU Junzhe; LI Yushun; LV Lihua

    2005-01-01

    The influence of anti-freezing admixture on the alkali aggregate reaction in mortar was analyzed with accelerated methods. It is confirmed that the addition of sodium salt ingredients of anti-freezing admixture accelerates the alkali silica reaction to some extent, whereas calcium salt ingredient of anti-freezing admixture reduces the expansion of alkali silica reaction caused by high alkali cement. It is found that the addition of the fly ash considerably suppresses the expansion of alkali silica reaction induced by the anti-freezing admixtures.

  5. Concrete alkali-silica reaction and nuclear radiation damage

    International Nuclear Information System (INIS)

    The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 108 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

  6. Investigation on the expansion value of turbine generator foundation affected by Alkali-Silica reaction

    International Nuclear Information System (INIS)

    It is well known that expansion of concrete is occurred in the concrete structure affected by Alkali-silica reaction in addition to crack propagation. However it is difficult to measure expansion value after the alkali silica reaction occurrence in a structure. The turbine generator foundation which is the core discussion item of this paper has been monitored for expansion values and reinforcement bar strains, upon which the expansion of the structure due to affect of the alkali silica reaction is found out. The total expansion values of the turbine generator foundation due to the affect of Alkali-silica reaction were estimated according to those measurement results in order to be utilized for a turbine generator foundation analysis. (authors)

  7. Assessment of concrete bridge decks with alkali silica reactions

    DEFF Research Database (Denmark)

    Eriksen, Kirsten; Jansson, Jacob; Geiker, Mette Rica

    , Bagsværd, Denmark to provide information on the damage condition as well as the residual reactivity of the concrete. The Danish Road Directory’s guidelines for inspection and assessment of alkali silica damaged bridges will be briefly presented, and proposed modifications will be describe...

  8. Alkali-silica reaction resistant concrete using pumice blended cement

    Science.gov (United States)

    Ramasamy, Uma

    Durability of structures is a major challenge for the building industry. One of the many types of concrete deterioration that can affect durability is alkali-silica reaction (ASR). ASR has been found in most types of concrete structures, including dams, bridges, pavements, and other structures that are 20 to 50 years old. The degradation mechanism of ASR produces a gel that significantly expands in the presence of water as supplied from the surrounding environment. This expansion gel product can create high stresses and cracking of the concrete, which can lead to other forms of degradation and expensive structural replacement costs. The four essential factors that produce an expansive ASR gel in concrete are the presence of alkalis, siliceous aggregate, moisture, and free calcium hydroxide (CH). If concrete is starved of any one of these essential components, the expansion can be prevented. Reducing CH through the use of a supplementary cementitious material (SCM) such as natural pozzolan pumice is the focus of this research. By using a pozzolan, the amount of CH is reduced with time based on the effectiveness of the pozzolan. Many pozzolans exist, but one such naturally occurring pozzolanic material is pumice. This research focuses on determining the effect of a finely ground pumice as a SCM in terms of its resistance to ASR expansion, as well as improving resistance to other potential concrete durability mechanisms. In spite of having high alkali contents in the pumice, mixtures containing the SCM pumice more effectively mitigated the ASR expansion reaction than other degradation mechanisms. Depending on the reactivity of the aggregates and fineness of the pumice, 10-15% replacement of cement with the pumice was found to reduce the ASR expansion to the acceptable limits. The amount of CH remaining in the concrete was compared to the ASR expansion in order to improve understanding of the role of CH in the ASR reaction. Thermo-gravimetric analysis (TGA) and X

  9. Alkali-Silica Reaction Inhibited by LiOH and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A high alkali reactive aggregate-zeolitization perlite was used to test the long-term effectiveness of LiOH in inhibiting alkali-silica reaction.In this paper,the rigorous conditions were designed that the mortar bars had been cured at 80℃ for 3 years after autoclaved 24 hours at 150℃.Under this condition,LiOH was able to inhibit the alkali-silica reaction long-term effectiveness.Not only the relationship between the molar ratio of n(Li)/(Na) and the alkali contents in systems was established, but also the governing mechanism of such effects was also studied by SEM.

  10. Mechanical effects of alkali silica reaction in concrete studied by SEM-image analysis

    OpenAIRE

    Ben Haha, Mohsen

    2006-01-01

    The occurrence of alkali-silica and alkali-silicate reactions causes damage in concrete. Even though the reaction has been known for some time, the progress of reaction in affected structures is difficult to predict. This research programme aims to study the relationship between the progress of the reaction and the mechanical properties of the concrete in order to support better prognosis of the effect of ASR on affected structure. The basic principal of the research programme is to character...

  11. Mechanical effects of alkali silica reaction in concrete studied by SEM-image analysis

    OpenAIRE

    Ben Haha, Mohsen; Scrivener, Karen

    2007-01-01

    The occurrence of alkali-silica and alkali-silicate reactions causes damage in concrete. Even though the reaction has been known for some time, the progress of reaction in affected structures is difficult to predict. This research programme aims to study the relationship between the progress of the reaction and the mechanical properties of the concrete in order to support better prognosis of the effect of ASR on affected structure. The basic principal of the research programme is to character...

  12. Experimental and modelling study of the alkali-silica-reaction in concrete

    OpenAIRE

    Dunant, Cyrille

    2009-01-01

    The alkali-silica reaction (ASR) is a durability issue of concrete. The amorphous silica of aggregates reacts with the alkalies present in the cement paste pore solution to form a hydrophilic gel which swells in the presence of moisture. Many mass concrete structures are affected and understanding of the reaction and its development is crucial, notably for dam owners and managers. Although some parameters affecting the reaction are well understood, such as temperature, others which depend on ...

  13. Investigation on lithium migration for treating alkali-silica reaction affected concrete

    OpenAIRE

    Silva De Souza, L.M.; Polder, R.B.; Copuroglu,O.

    2014-01-01

    Alkali-silica reaction (ASR) is one of the major deterioration mechanisms that affect numerous concrete structures worldwide. During the reaction, hydroxyl and alkali (sodium and potassium ) ions react with certain siliceous compounds in the aggregate, forming a hygroscopic gel. The gel absorbs water from the cement paste and swells, possibly leading to deleterious expansion and cracking of the structure. Once ASR is detected in existing structures, there are no treatments to stop it and prol...

  14. Alkali silica reaction in concrete induced by mortar adhered to recycled aggregate

    OpenAIRE

    Etxeberria, M.; Vázquez, E.

    2010-01-01

    The durability of recycled concrete must be determined before this material can be used in construction. In this paper the alkali-silica reaction in recycled concrete is analyzed. The recycled concrete is made with recycled aggregates, composed by original limestone aggregates and adhered mortar with reactive silica sand, and high alkali content cement. Due to the manufacturing process used for concrete production and the high water absorption capacity of recycled aggregates, cement accumulat...

  15. Detection of alkali-silica reaction swelling in concrete by staining

    Science.gov (United States)

    Guthrie, Jr., George D.; Carey, J. William

    1998-01-01

    A method using concentrated aqueous solutions of sodium cobaltinitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by yellow staining, and alkali-poor, Ca--Si gels are identified by pink staining.

  16. Significance of Alkali-Silica reaction in nuclear safety-related concrete structures

    International Nuclear Information System (INIS)

    Nuclear Power Plant license renewal up to 60 years and possible life extension beyond has established a renewed focus on long-term aging of nuclear generating stations materials, and particularly, on concrete. Large irreplaceable sections of most nuclear generating stations include concrete components. The Expanded Materials Degradation Analysis, jointly performed by the Department of Energy, the U.S. Nuclear Regulatory Commission, the Academia and the Power Generation Industry, identified the need to develop a consistent knowledge base of alkali-silica reaction (ASR) within concrete as an urgent priority (Graves et al., 2014). ASR results in an expansion of Concrete produced by the reaction between alkali (generally from cement), reactive aggregate (like amorphous silica) and water absorption. ASR causes expansion, cracking and loss of mechanical properties. Considering that US commercial reactors in operation enter the age when ASR distress can be potentially observed and that numerous non-nuclear infrastructures (transportation, energy production) in a majority of the States have already experienced ASR-related concrete degradation, the susceptibility and significance of ASR for nuclear concrete structures must be addressed. This paper outlines an on-going research program including the investigation of the possibility of ASR in nuclear power plants, and the assessment of the residual shear bearing capacity of ASR-subjected nuclear structures. (authors)

  17. Investigation of safety margin for turbine generator foundation affected by Alkali Silica reaction based on non-linear structure analysis

    International Nuclear Information System (INIS)

    A turbine generator foundation is a reinforced concrete structure having a table deck and columns to support equipments. After operation of the plant, the expansion of the table deck in turbine longitudinal axis has been observed. By investigation of concrete material properties, it was found that the expansion has been caused by alkali-silica reaction. This study has been performed to evaluate the safety allowance of strength capacity of the turbine generator foundation by nonlinear analysis using beam element model with elongation, rebar strain and material properties data which have been measured for almost 30 years in actual foundation. (authors)

  18. Influence of water on alkali-silica reaction: Experimental study and numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Poyet, Stephane [CEA Saclay, DEN/DANS/DPC/SCCME/LECBA, B158, 91191 Gif sur Yvette (France); Sellier, Alain [LMDC, INSA PS, 135 Avenue de Rangueil, 31077 Toulouse Cedex 4 (France); Capra, Bruno [Oxand SA, 36bis Avenue Franklin Roosevelt, 77210 Avon (France); Thevenin-Foray, Genevieve [Universite Lyon 1 2MS ETRA GC, 82 Boulevard Niels BOHR, Domaine Scientifique de la DOUA, 69622 Villeurbanne Cedex (France); Torrenti, Jean-Michel [IRSN, BP17, 92262 Fontenay aux Roses Cedex (France); Tournier-Cognon, Helene [DER DF, Les Renardieres, Route de Sens, Ecuelles, 77818 Moret sur Loing (France); Bourdarot, Eric [Direction de l' Equipement, CIH, Savoie Technolac, 73373 Le Bourget du Lac (France)

    2006-07-01

    Alkali-silica reaction (ASR) is a concrete pathology due to chemical reactions involving reactive silica from reactive aggregates and the inner solution of concrete. Main effects are swelling, cracking, and reduction in the mechanical properties of affected concretes. Water is very important for ASR; the more available water, the more expansion and degradation. This article presents new laws for modeling of the influence of water upon ASR. They are based on experimental results and then used to simulate results taken out of the scientific literature. (authors)

  19. Influence of water on alkali-silica reaction: Experimental study and numerical simulations

    International Nuclear Information System (INIS)

    Alkali-silica reaction (ASR) is a concrete pathology due to chemical reactions involving reactive silica from reactive aggregates and the inner solution of concrete. Main effects are swelling, cracking, and reduction in the mechanical properties of affected concretes. Water is very important for ASR; the more available water, the more expansion and degradation. This article presents new laws for modeling of the influence of water upon ASR. They are based on experimental results and then used to simulate results taken out of the scientific literature. (authors)

  20. Cathodoluminescence microscopy and petrographic image analysis of aggregates in concrete pavements affected by alkali-silica reaction

    Energy Technology Data Exchange (ETDEWEB)

    Stastna, A., E-mail: astastna@gmail.com [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Sachlova, S.; Pertold, Z.; Prikryl, R. [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Leichmann, J. [Department of Geological Sciences, Faculty of Science, Masaryk University in Brno, Kotlarska 267/2, 611 37 Brno (Czech Republic)

    2012-03-15

    Various microscopic techniques (cathodoluminescence, polarizing and electron microscopy) were combined with image analysis with the aim to determine a) the modal composition and degradation features within concrete, and b) the petrographic characteristics and the geological types (rocks, and their provenance) of the aggregates. Concrete samples were taken from five different portions of Highway Nos. D1, D11, and D5 (the Czech Republic). Coarse and fine aggregates were found to be primarily composed of volcanic, plutonic, metamorphic and sedimentary rocks, as well as of quartz and feldspar aggregates of variable origins. The alkali-silica reaction was observed to be the main degradation mechanism, based upon the presence of microcracks and alkali-silica gels in the concrete. Use of cathodoluminescence enabled the identification of the source materials of the quartz aggregates, based upon their CL characteristics (i.e., color, intensity, microfractures, deformation, and zoning), which is difficult to distinguish only employing polarizing and electron microscopy. - Highlights: Black-Right-Pointing-Pointer ASR in concrete pavements on the Highways Nos. D1, D5 and D11 (Czech Republic). Black-Right-Pointing-Pointer Cathodoluminescence was combined with various microscopic techniques and image analysis. Black-Right-Pointing-Pointer ASR was attributed to aggregates. Black-Right-Pointing-Pointer Source materials of aggregates were identified based on cathodoluminescence characteristics. Black-Right-Pointing-Pointer Quartz comes from different volcanic, plutonic and metamorphic parent rocks.

  1. Relation of expansion due to alkali silica reaction to the degree of reaction measured by SEM image analysis

    International Nuclear Information System (INIS)

    Scanning Electron Microscopy Image Analysis (SEM-IA) was used to quantify the degree of alkali silica reaction in affected microbars, mortar and concrete prisms. It was found that the degree of reaction gave a unique correlation with the macroscopic expansion for three different aggregates, stored at three temperatures and with two levels of alkali. The relationships found for the concretes and the mortars overlap when normalised by the aggregate content. This relationship seems to be linear up to a critical reaction degree which coincides with crack initiation within the reactive aggregates

  2. Measurement of alkali-silica reaction progression by ultrasonic waves attenuation

    International Nuclear Information System (INIS)

    Development of non-destructive methods, developed specifically for assessing the damage induced by alkali-silica reaction (ASR) in concrete structures, is needed in order to carry out a systematic evaluation of the concrete condition. The aim of this study is to monitor the evolution of the ASR-damage in laboratory with concrete samples with ultrasonic pulse velocity and attenuation of ultrasonic waves methods. For this study, results of both methods were compared with expansion and mass variation. One reactive concrete mixture was made with reactive aggregate, and one other mixture, incorporating non-reactive aggregate, was made as a control. Specimens were kept at 38 deg. C in a 1 mol l-1 NaOH solution to accelerate the reaction. Attenuation of transmitted ultrasonic waves appeared to be more appropriate for the evaluation of ASR-damage compared with pulse velocity. The attenuation of accelerated reactive concrete cylinders increased by 90% after 1 year while it increased by 40% for the non-reactive concrete used as a control. Major part of the attenuation increase in the non-reactive concrete is due to liquid absorption. This work suggests that in-situ non-destructive techniques based on ultrasonic wave attenuation, like ultrasonic attenuation tomography, should be developed in order to evaluate the development of ASR in concrete structures. Petrographic examination confirmed that damage to concrete is associated with ASR

  3. Monitoring, Modeling, and Diagnosis of Alkali-Silica Reaction in Small Concrete Samples

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gribok, Andrei V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. This report describes alkali-silica reaction (ASR) degradation mechanisms and factors influencing the ASR. A fully coupled thermo-hydro-mechanical-chemical model developed by Saouma and Perotti by taking into consideration the effects of stress on the reaction kinetics and anisotropic volumetric expansion is presented in this report. This model is implemented in the GRIZZLY code based on the Multiphysics Object Oriented Simulation Environment. The implemented model in the GRIZZLY code is randomly used to initiate ASR in a 2D and 3D lattice to study the percolation aspects of concrete. The percolation aspects help determine the transport properties of the material and therefore the durability and service life of concrete. This report summarizes the effort to develop small-size concrete samples with embedded glass to mimic ASR. The concrete samples were treated in water and sodium hydroxide solution at elevated temperature to study how ingress of sodium ions and hydroxide ions at elevated temperature impacts concrete samples embedded with glass. Thermal camera was used to monitor the changes in the concrete sample and results are summarized.

  4. A computational linear elastic fracture mechanics-based model for alkali-silica reaction

    International Nuclear Information System (INIS)

    This article presents a fracture mechanics model for Alkali-Silica Reaction (ASR). The model deals with the case of a concrete made up of dense aggregates submitted to chemical attack. The chemistry and diffusion (of ions and gel) are not modelled. The focus is put on the mechanical consequences of the progressive replacement of the outer layer of the aggregate by a less dense gel. A schematic cracking pattern is assumed: a ring-shaped crack appears in the cement paste surrounding the spherical aggregate depending on the pressure build-up. The onset of cracking is determined using an incremental energy criterion. The stored elastic energy and deformation of a given configuration are determined assuming that each aggregate behaves as if it was embedded in an infinite cement paste matrix. The calculations are performed by Finite Element Analysis. We note a very different behaviour of aggregates of different sizes. Adding the contributions of different aggregate sizes leads to an estimation of the global free expansion of a concrete of given aggregate size distribution. A rate of attack is identified that leads to recover the usual sigmoid ASR expansion curve. (authors)

  5. Microscopy and Cathodoluminescence Spectroscopy Characterization of Quartz Exhibiting Different Alkali-Silica Reaction Potential.

    Science.gov (United States)

    Kuchařová, Aneta; Götze, Jens; Šachlová, Šárka; Pertold, Zdeněk; Přikryl, Richard

    2016-02-01

    Different quartz types from several localities in the Czech Republic and Sweden were examined by polarizing microscopy combined with cathodoluminescence (CL) microscopy, spectroscopy, and petrographic image analysis, and tested by use of an accelerated mortar bar test (following ASTM C1260). The highest alkali-silica reaction potential was indicated by very fine-grained chert, containing significant amounts of fine-grained to cryptocrystalline matrix. The chert exhibited a dark red CL emission band at ~640 nm with a low intensity. Fine-grained orthoquartzites, as well as fine-grained metamorphic vein quartz, separated from phyllite exhibited medium expansion values. The orthoquartzites showed various CL of quartz grains, from blue through violet, red, and brown. Two CL spectral bands at ~450 and ~630 nm, with various intensities, were detected. The quartz from phyllite displayed an inhomogeneous dark red CL with two CL spectral bands of low intensities at ~460 and ~640 nm. The massive coarse-grained pegmatite quartz from pegmatite was assessed to be nonreactive and displayed a typical short-lived blue CL (~480 nm). The higher reactivity of the fine-grained hydrothermal quartz may be connected with high concentrations of defect centers, and probably with amorphized micro-regions in the quartz, respectively; indicated by a yellow CL emission (~570 nm). PMID:26790877

  6. Classification of alkali-silica reaction and corrosion distress using acoustic emission

    Science.gov (United States)

    Abdelrahman, Marwa; ElBatanouny, Mohamed; Serrato, Michael; Dixon, Kenneth; Larosche, Carl; Ziehl, Paul

    2016-02-01

    The Nuclear Regulatory Commission regulates approximately 100 commercial nuclear power reactor facilities that contribute about 20% of the total electric energy produced in the United States. Half of these reactor facilities are over 30 years old and are approaching their original design service life. Due to economic and durability considerations, significant portions of many of the facilities were constructed with reinforced concrete, including the containment facilities, cooling towers, and foundations. While most of these concrete facilities have performed exceptionally well throughout their initial expected service life, some are beginning to exhibit different forms of concrete deterioration. In this study, acoustic emission (AE) is used to monitor two main concrete deterioration mechanisms; alkali-silica reaction (ASR) distress and corrosion of reinforcing steel. An accelerated ASR test was conducted where specimens were continuously monitored with AE. The results show that AE can detect and classify damage due to ASR distress in the specimens. AE was also used to remotely monitor active corrosion regions in a reactor facility. AE monitoring of accelerated corrosion testing was also conducted on a concrete block specimen cut from a similar reactor building. Electrochemical measurements were conducted to correlate AE activity to quantifiable corrosion measurements and to enhance capabilities for service life prediction.

  7. Comparative study of the alkali-silica reaction (ASR in granitic aggregates

    Directory of Open Access Journals (Sweden)

    Velasco-Torres, A.

    2010-06-01

    Full Text Available The reaction between certain reactive components of aggregates (like opal and metaestable silica and concrete pore solution is well documented. Nevertheless, in this study it has been shown that some aggregates, like granite, could develop a rapid or slow alkali-silica reaction (ASR depending on the deleterious component involved. Mortar bars were cast with two granitic aggregates extracted from concrete cores drilled in two Spanish Dams affected by ASR, being classified as granitic rocks. The main difference between them is the reactive component: microcrystalline quartz in one case and strained and microcracked quartz in the other case. A petrographic examination was carried out in the mortar bars. Thin sections were cut and the alkalisilica gel was stained for an easier detection. Then, the thin sections were examinated with a stereomicroscope comparing the differences in the progress of the ASR for both aggregates. It can be concluded that the main mechanism of formation and storage of gel is associated to the micro-cracks instead of the subgrain boundaries.

    La reacción entre los componentes de la fase intersticial del hormigón y áridos con minerales como el ópalo o la sílice metaestable, se encuentra bien documentada. Sin embargo, en este estudio, se ha detectado que dentro de un mismo tipo de roca, como es el granito, puede haber diferencias en el tipo de reacción (lenta o rápida dependiendo del componente reactivo que aparezca en la misma. Se han fabricado barras de mortero con los áridos extraídos de dos presas españolas afectadas por la reacción álcali-sílice. Estos áridos son rocas graníticas y la diferencia entre ambos reside en que una de las muestras contiene cuarzo microcristalino como componente reactivo y, la otra, cuarzo deformado. Mediante el estudio petrográfico de barras de mortero y el teñido del gel álcali-sílice se ha podido observar la evolución y progreso de la reacción para cada

  8. The use of fly ash and metakaolin for the prevention of alkali-silica reaction and delayed ettringite formation in concrete

    OpenAIRE

    Silva, A. Santos; Ribeiro, A. Bettencourt; Jalali, Said; Divet, Loic

    2006-01-01

    One of the most popular preventive measures to minimize the occurrence of chemical expansive reactions, namely the alkali-silica reaction (ASR) and delayed ettringite formation (DEF) in hardened concrete is the use of supplementary cementing materials (SCMs). Several studies have been performed along the last few years related with the use of fly ashes in the suppression of expansion due to ASR. However, relatively little attention are been focused in its effectiveness to control the DEF in c...

  9. The use of fly ashes and metakaolin for the prevention of alkali-silica reaction and delayed ettringite formation in concrete

    OpenAIRE

    Santos Silva, A.; BETTENCOURT RIBEIRO, A; Jalali, S; DIVET, L

    2006-01-01

    One of the most popular preventive measures to minimize the occurrence of chemical expansive reactions, namely the alkali-silica reaction (ASR) and delayed ettringite formation (DEF) in hardened concrete is the use of supplementary cementing materials (SCMs). Several studies are been performed along the last years related the use of fly ashes in the suppression of expansion due to ASR. However, relatively little attention are been focused in its effectiveness to control the DEF in concrete, a...

  10. Alkali-silica reaction of aggregates for concrete pavements in Chihuahua’s State, Mexico

    Directory of Open Access Journals (Sweden)

    Olague, C.

    2002-12-01

    Full Text Available The concrete of pavements must resist the climatic conditions, heavy traffic, chemical agents or any other type of aggressive agent. A methodology for characterizing materials that would influence concrete durability was developed considering chemical and physical factors. This methodology allows the consideration of several factors like physiography, geology, and climate, among others that would be of great importance to prevent future durability problems of pavements. This methodology takes into account several tests and this paper presents the results of potential reactivity aggregates of the State of Chihuahua. The tests for evaluating the reactive siliceous aggregate and the potential alkali-silica reactivity were performed according to the: petrographic examination (ASTM C 295 and standard quick chemical test (ASTM C 289. 38% of the tested sites resulted innocuous, 48% potentially reactive and 13% reactive. It is discussed the benefit of applying a conscious methodology in order to obtain the best results with a representative quantity of tests.

    El hormigón de los pavimentos debe ser resistente a las condiciones climáticas, tránsito pesado, agentes químicos o cualquier otro tipo de agente agresivo. Se desarrolló una metodología para caracterización de materiales considerando factores físicos y químicos que influyen en la durabilidad del hormigón. Esta metodología se basa en la consideración de varios factores como: fisiografía, geología y clima, entre otros, que podrían ser de gran importancia para prevenir futuros problemas de durabilidad en pavimentos de hormigón. La metodología en cuestión considera varias pruebas, en este artículo se presentan los resultados de la reactividad potencial de los áridos del Estado de Chihuahua. Las pruebas para evaluar la reactividad de áridos silíceos y la reactividad potencial álcali-sílice fueron ejecutadas de acuerdo a: examen petrográfico (ASTM C 295 y la prueba qu

  11. Study on material properties in order to apply for structural analysis of turbine generator foundation affected by Alkali-Silica reaction

    International Nuclear Information System (INIS)

    It is well known that material properties (compressive strength, elastic modulus) of a concrete core specimen taken from a structure, which has been affected by alkali-silica reaction (ASR), are reduced significantly in comparison to those of sound concrete. On the other hand, in-situ tests of reinforcement concrete structures also affected by ASR are reported to show only insignificant reduction of rigidity and strength capacities of the structures. The difference of the affect of ASR on a core and a structure is understood to be occurred due to pre-stress effect caused by ASR on the concrete. However, there are only a few reports which show a quantitative evaluation of this effect. Material properties of concrete structure affected by ASR are studied quantitatively by literature review, in-situ tests of actual foundation and model tests. (authors)

  12. The Influence of Calcined Clay Pozzolan, Low-Cao Steel Slag and Granite Dust On the Alkali-Silica Reaction in Concrete

    Directory of Open Access Journals (Sweden)

    James Sarfo-Ansah

    2015-08-01

    Full Text Available The influence of low CaO steel slag, calcined clay and granite dust on the alkali-silica reaction was investigated over a period of 35 days under accelerated curing conditions. The mineral admixtures were used to replace varying portions of high alkali Portland limestone cement up to an admixture content of 25% in order to study their effect on the alkali-silica reaction (ASR. Portland limestone cement used for the study had a total Na2Oeq of 4.32. XRD analysis of hydrated mortar bar samples confirmed the formation of an expansive sodium silica gel in the reference Portland cement mortar bar as the agent responsible for ASR. Stable calcium silicates were formed in the mortar bars containing calcined clay in increasing quantities whilst the presence of the sodium silicate gel decreased.The occurrence of these stable silicates in hydrated samples containing steel slag and granite dust was however minimal, compared to calcined clay cement mortars. The highest expansion was recorded for granite dust mortar bars, reaching a maximum of 25.98% at 35 days. Mortar-bar expansion decreased as calcined clay content in the cement increased;mortar bars with 25% calcined clay were the least expansive recording expansion less than 0.1% at all test ages. Whilst the expansion was reduced by between 42.5% and 107.8% at 14 days with increasing calcined clay content, expansion rather increased between 36.8% and 169.5% at 14 days with increasing granite dust content.Steel slag mortar bars experienced reduction in 14 days expansion between 14.3% - 46.2%.The study confirms that steel slag and calcined clay pozzolan have greater influence on ASR in mortar bars than granite dust and shows that calcined clay and low CaO steel slag could be considered as remedial admixtures for ASR at replacement levels of 25% and 15% respectively.

  13. GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Vanderbilt Univ., Nashville, TN (United States)

    2015-09-01

    Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document the progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we’ve implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture

  14. GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

    International Nuclear Information System (INIS)

    Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document the progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we've implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture

  15. Durability of Concrete Subjected to the Combined Action of Alkali-silica Reaction and Sulfate Attack%碱-硅酸反应和硫酸盐侵蚀复合作用下的混凝土耐久性

    Institute of Scientific and Technical Information of China (English)

    沈佳燕; 施韬; 杨杨

    2012-01-01

    碱-硅酸反应(ASR)和硫酸盐侵蚀是影响混凝土耐久性的两个重要因素.目前,对于单一因素作用下混凝土劣化过程的研究已有诸多报道,但关于混凝土在碱-硅酸反应和硫酸盐侵蚀复合作用下的损伤失效过程及机理研究却很少.本文介绍了近年来国内外在碱-硅酸反应和硫酸盐侵蚀方面的研究现状,主要阐述了它们各自的膨胀机理和抑制措施.在对Grattan等人试验中得到的膨胀数据、X射线衍射图和扫描电子显微镜图进行分析的基础上,讨论了混凝土在这两种因素复合作用下可能出现的膨胀值变化和强度变化,并提出有效的抑制措施.%Alkali-silica reaction (ASR) and sulfate attack are two of the most important problems on concrete durability. The deterioration of concrete under single destructive action have been broadly investigated, but the damage process and the corresponding mechanisms subjected to combined action of ASR and sulfate attack have rarely studied yet. This paper introduces the recent research progress in alkali-silica reaction and sulfate attack achieved home and abroad,and mainly describes the expanding mechanisms and inhibitive measures of each reaction. The probable changes of expansion and strength of concrete subjected to combined action of ASR and sulfate attack are discussed on the base of analyzing experimental results of expansion, X-Ray diffractogram and SEM micrograph by Grattan el al, and the effective inhibitive measures are also been proposed.

  16. Application of micro X-ray diffraction to investigate the reaction products formed by the alkali silica reaction in concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Dähn, R.; Arakcheeva, A.; Schaub, Ph.; Pattison, P.; Chapuis, G.; Grolimund, D.; Wieland, E.; Leemann, A. (Ecole); (PSI); (Phase Solutions); (ESRF)

    2015-12-21

    Alkali–silica reaction (ASR) is one of the most important deterioration mechanisms in concrete leading to substantial damages of structures worldwide. Synchrotron-based micro-X-ray diffraction (micro-XRD) was employed to characterize the mineral phases formed in micro-cracks of concrete aggregates as a consequence of ASR. This particular high spatial resolution technique enables to directly gain structural information on ASR products formed in a 40-year old motorway bridge damaged due to ASR. Micro-X-ray-fluorescence was applied on thin sections to locate the reaction products formed in veins within concrete aggregates. Micro-XRD pattern were collected at selected points of interest along a vein by rotating the sample. Rietveld refinement determined the structure of the ASR product consisting of a new layered framework similar to mountainite and rhodesite. Furthermore, it is conceivable that understanding the structure of the ASR product may help developing new technical treatments inhibiting ASR.

  17. Structural evaluation of a prestressed concrete bridge under an alkali-silica reaction; Evaluacion estructural de un puente de hormigon pretensado afectado por una reaccion alcali-silice

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero Garcia, I.; Bermudez Adriozola, B.

    2010-07-01

    The Central Laboratory of Structures and Materials (CEDEX) was commissioned by the National Department of Highways to evaluate the safety conditions of one bridge built on 1997, which is part of the net of the Spanish National Highways. Even at the first inspection many cracks were detected in the concrete deck, associated with expansion concrete processes. This examination revealed that concrete deterioration was not associated with any reinforcement corrosion process; in fact, there were no symptoms of this pathology all along the bridge. for that reason the internal chemical reactions were considered as the most probable cause for the expansion of concrete, as no symptoms of deterioration due to external attack were found. In order to check the origin of concrete expansion, some tests were carried out on concrete samples drilled on the decks. Results of these tests show that there had been internal reactions in concrete mass which explains its expansion and the appearance of those cracks observed. Further more, some other activities were also carried out on site to estimate the importance of the structural damages, as topographic levelling and dynamic testing of the decks. Also the mechanical properties of concrete probes were tested at laboratory. This article shows the main results obtained on the study carried on to determine the cause and significance of the structural damages of the bridge. (Author) 3 refs.

  18. The role of residual cracks on alkali silica reactivity of recycled glass aggregates

    DEFF Research Database (Denmark)

    Maraghechi, Hamed; Shafaatian, Seyed-Mohammad-Hadi; Fischer, Gregor;

    2012-01-01

    Despite its environmental and economical advantages, crushed recycled glass has limited application as concrete aggregates due to its deleterious alkali-silica reaction. To offer feasible mitigation strategies, the mechanism of ASR should be well understood. Recent research showed that unlike some...... percentages of reactive microcracks which may explain why ASR expansions are lowered by reducing the size of glass aggregates....

  19. Examination of the concrete from an old Portuguese dam: Texture and composition of alkali-silica gel

    International Nuclear Information System (INIS)

    Exudations and pop-outs were identified in the interior galleries of a large dam built in the 1960s. The samples collected were examined by a Scanning Electron Microscope. A dense material with a smooth surface and drying shrinkage cracks or a spongy texture were observed in the samples. The semi-quantitative composition was obtained by energy dispersive spectrometry (EDS) and it was concluded that this material corresponds to alkali-silica gel, composed of SiO2-Na2O-K2O-CaO. A viscous white product in contact with an aggregate particle in a cone sampled from a pop-out was observed through use of the scanning electron microscope and it has characteristics similar to the gel present in the exudations and cavities. Reference is made to the potential alkali reactivity of the aggregate present in the concrete. The texture and composition of the products probably resulting from an alkali-silica reaction are presented, set out in ternary diagrams, and discussed

  20. Estudo das reações alcalis-sílica associadas ao uso da lama vermelha em argamassas colantes e de revestimento Study of alkali-silica reactions associated with the use of red mud in plastering mortars

    Directory of Open Access Journals (Sweden)

    D. V. Ribeiro

    2012-03-01

    Full Text Available A incorporação de resíduos industriais em matrizes cimentícias, com o objetivo de inertização, é uma alternativa de reutilização que tem sido bastante estudada nos últimos anos. No presente trabalho, estudou-se a lama vermelha, resíduo sólido gerado no processo de beneficiamento da bauxita e que, devido a seu elevado pH, é considerado "perigoso". Apesar do uso deste resíduo ter sido reportada em trabalhos anteriores, algumas patologias podem estar associadas à sua utilização, devido à elevada concentração de íons alcalinos (principalmente o sódio, favorecendo as reações álcalis-sílica (RAS e às dificuldades de moldagem (reologia devido à elevada finura deste resíduo. Apesar destes prováveis problemas provenientes do uso indiscriminado da lama vermelha como adição às argamassas e concretos, ainda são poucas as pesquisas que os contemplam, sendo este o foco do presente trabalho. Foram verificadas as propriedades reológicas das argamassas, utilizando um reômetro e a avaliação da RAS, de acordo com as normas ASTM C 1260-07 e NBR 11582. Os resultados obtidos foram bastante satisfatórios quanto ao comportamento das argamassas frente à RAS, apesar da elevada concentração de álcalis na lama vermelha, com grande influência reológica.The incorporation of industrial wastes in cementitious matrices, with the goal of inertization, is an alternative of reuse that has been extensively studied in recent years. In this paper, the red mud, the main waste generated in aluminum and alumina production by the Bayer process from bauxite ore and considered "hazardous" due to the high pH, was studied. Despite the use of this waste have been reported in previous studies, some pathologies may be associated with its use, due to high concentration of alkali ions (mainly sodium, favoring the alkali-silica reactions (ASR and the difficulties of molding (rheology because of high fineness of this waste. Despite these potential

  1. A nonlinear wave mixing method for detecting Alkali-Silica reactivity of aggregates

    Science.gov (United States)

    Liu, M.; Tang, G.; Jacobs, L. J.; Qu, J.

    2012-05-01

    Alkali-silica reaction (ASR) is a deleterious reaction in concrete. Significant ASR damage could undermine the durability of concrete structures and may result in reduced service life. Several nondestructive techniques based on ultrasound have been used to assess ASR damage. It has been shown that nonlinear ultrasound is more sensitive to internal stresses as well as to micro-cracks induced by ASR damage. In this investigation, we developed a co-linear wave mixing method for assessing ASR damage in concrete. By mixing two longitudinal waves, a new longitudinal wave with a lower frequency is generated. The amplitude of this new wave is proportional to the acoustic nonlinear parameter β which can then be obtained from the frequency spectrum of the newly generated longitudinal wave. Our experimental results show that (i) the acoustic nonlinearity parameter is closely correlated to ASR damage in concrete, (ii) the nonlinear wave mixing technique developed here is capable of measuring the changes in the acoustic nonlinearity parameter caused by ASR damage, even in its early stages, and (iii) the nonlinear wave mixing method has the potential to identify the different stages of ASR damage and to track the intrinsic characteristics of the ASR damage.

  2. Nouvelle approche pour le suivi de la réactivité de phases SiO2 soumises à la Réaction Alcali Silice (RAS New approach for monitoring the reactivity of SiO2 phases subject to Alkali Silica Reaction (SAR

    Directory of Open Access Journals (Sweden)

    Harfouche M.

    2012-09-01

    Full Text Available Nous avons suivi- au moyen de la microscopie électronique à balayage environnementale (MEBE la diffraction X et la spectroscopie d’absorption des rayons X sous rayonnement synchrotron (XANES- la réactivité de certaines phases SiO2 lors du processus de la Réaction Alcali Silice (RAS. Cette réactivité est étroitement liée à la structure locale autour des atomes de silicium ainsi qu’à la présence d’impuretés comme le fer. Dans le cas du silex brut, la raie blanche du seuil K du fer ressemble davantage à celle de Fe3O4 ce qui permet de déduire la présence d’un mélange de Fe2+/Fe3+ dans le silex de départ. Après réaction, l’allure du spectre d’absorption des rayons X au seuil K du fer du silex est conservée avec un léger déplacement de la raie blanche vers les hautes énergies. Cette augmentation montre une prédominance de la valence Fe3+ au détriment de la valence Fe2+. Les résultats montrent que le fer participe à la stabilisation de la structure des phases formées. Cette étude peut être étendue à d’autres éléments traces présents dans la structure du silex de départ. In this study the reactivity of some SiO2 phases under Alkali Silica Reaction (RAS process is followed, using the environmental scanning electron microscopy (ESEM X-ray diffraction and absorption spectroscopy X-ray synchrotron radiation (XANES. This reactivity is closely related to the local structure around the silicon atoms and the presence of impurities such as iron. In the case of flint raw skate white iron K line is more like that of Fe3O4 which allows to deduce the presence of a mixture of Fe2+ / Fe3+ in the flint to start. After reaction, the shape of the spectrum of X-ray absorption K edge of iron in the flint is retained with a slight displacement of the white stripe to high energies. This increase shows a predominance of the valence Fe3+ at the expense of Fe2+ valence. The results show that iron is involved in stabilizing the

  3. The Mechanism of the Eeffect of Mineral Admixtures on the Expansion of Aalkali-silica Reaction

    Institute of Scientific and Technical Information of China (English)

    WANG Aiqin; Niu Jishou; ZHANG Chengzhi

    2008-01-01

    On the base of the influence rule of silica fume, slag and fly ash on alkali-silica reaction under the condition of 70℃, the mechanism of the effect of mineral admixtures on alkali-silica reaction is studied further in the paper. The results show that the effects of mineral admixtures on alkali-silica reaction are mainly chemistry effect and surface physichemistry effect. Under suitable condition, the chemistry effect may make alkali-silica reaction to be inhibited effectively, but the physichemistry effect only make alkali-silica reaction to be delayed. The chemistry effect and the physichemistry effect of minerals admixture are relative to the content of Ca(OH)2 in system. Under the condition that there is a large quantity of Ca(OH)2, mineral admixture cannot inhibit alkali-silica reaction effectively. Only when Ca(OH)2 in the system is very less, it is possible that mineral admixture inhibits alkali-silica reaction effectively.

  4. Linear Array Ultrasonic Test Results from Alkali-Silica Reaction (ASR) Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Clayton, Dwight A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Khazanovich, Dr. Lev [Univ. of Minnesota, Minneapolis, MN (United States); Salles, Lucio [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-04-01

    The purpose of the U.S. Department of Energy Office of Nuclear Energy’s Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.This report presents results of the ultrasound evaluation of four concrete slabs with varying levels of ASR damage present. This included an investigation of the experimental results, as well as a supplemental simulation considering the effect of ASR damage by elasto-dynamic wave propagation using a finite integration technique method. It was found that the Hilbert Transform Indicator (HTI), developed for quantification of freeze/thaw damage in concrete structures, could also be successfully utilized for quantification of ASR damage. internal microstructure flaws, and reinforcement locations.

  5. Linear Array Ultrasonic Test Results from Alkali-Silica Reaction (ASR) Specimens

    International Nuclear Information System (INIS)

    The purpose of the U.S. Department of Energy Office of Nuclear Energy's Light Water Reactor Sustainability (LWRS) Program is to develop technologies and other solutions that can improve the reliability, sustain the safety, and extend the operating lifetimes of nuclear power plants (NPPs) beyond 60 years. Since many important safety structures in an NPP are constructed of concrete, inspection techniques must be developed and tested to evaluate the internal condition. In-service containment structures generally do not allow for the destructive measures necessary to validate the accuracy of these inspection techniques. This creates a need for comparative testing of the various nondestructive evaluation (NDE) measurement techniques on concrete specimens with known material properties, voids, internal microstructure flaws, and reinforcement locations.This report presents results of the ultrasound evaluation of four concrete slabs with varying levels of ASR damage present. This included an investigation of the experimental results, as well as a supplemental simulation considering the effect of ASR damage by elasto-dynamic wave propagation using a finite integration technique method. It was found that the Hilbert Transform Indicator (HTI), developed for quantification of freeze/thaw damage in concrete structures, could also be successfully utilized for quantification of ASR damage. internal microstructure flaws, and reinforcement locations.

  6. Detection of alkali-silica reaction by means of ultrasonic sounding - a pilot study

    Czech Academy of Sciences Publication Activity Database

    Lokajíček, Tomáš; Petružálek, Matěj; Svitek, Tomáš; Šťastná, A.; Šachlová, Š.

    Montréal: Canadian Institute of Mining , Metallurgy and Petroleum, 2015. ISBN 978-1-926872-25-4. [International Congress of Rock Mechanics /13./. Montréal (CA), 10.05.2015-13.05.2015] R&D Projects: GA ČR(CZ) GAP104/12/0915 Institutional support: RVO:67985831 Keywords : Mortar bar test * ASR * aggregates * ultrasonic sounding * time domain analysis * longitudinal wave velocity * frequency domain analysis Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  7. Mecanismes d'action des fines et des granulats de verre sur la reaction alcali-silice et la reaction pouzzolanique

    Science.gov (United States)

    Idir, Rachida

    Recycling composite glass with different colours in order to be manufactured into new glass products is at present not economically viable. Therefore, the search for new issues other than stockpile areas or dumping sites could be a serious opportunity. To a certain extent, one of the possible solutions is to use the recycled glass in manufacturing cements and in the preparation of concrete mixtures. However, it is essential to manage the two main behaviours that the glass can have when used in cement-based materials: (1) the use of glass as coarse aggregates reveals harmful behaviour related to alkali-silica reaction; (2) on the other hand, it can result in useful behaviour related to pozzolanic reaction if used as fine particles. Furthermore, the significant alkali content should not be overlooked as their mass corresponds to about 13% of the total mass of the glass and as they may activate the alkali-silica reaction. An experimental programme was conducted to provide answers to the various questions raised about the use of glass in cement-based materials. The first part of this work was primarily devoted to the evaluation of the reactive potential of glass in mortars (alkali and pozzolanic reactions). At this stage, nine classes of glass particles ranging from 3mum to 2.5 mm were considered. Then, fine glass particles were used in order to counteract the negative effect of some classes of coarse aggregates having revealed alkali-reactive behaviour. The second part of this work was performed to study the mechanisms that could explain the behaviours of fine and coarse particles in aqueous and concentrated environments. Different answers have been proposed to explain the observed behaviour in terms of grain sizes of glass. Keywords: Glass, Powder, Pozzolan, aggregates, alkali-reaction, alkali-aggregate reaction, alkali-silica reaction, Pouzzolanicity, alkalis, Mortars

  8. Alcali-silica reactions: Mechanisms for crack formations

    DEFF Research Database (Denmark)

    Goltermann, Per

    2006-01-01

    Alkali-silica reactions (ASR) are found all over the world and cause a large number of damage, which have lead to different sets of requirements in the different countries for the aggregates, the cements and the admixtures. One of the reasons for the damage and the different requirements is that...

  9. Observed Infant Reactions during Live Interparental Conflict

    Science.gov (United States)

    Du Rocher Schudlich, Tina D.; White, Clare R.; Fleischhauer, Emily A.; Fitzgerald, Kelly A.

    2011-01-01

    Associations between interparental conflict and infant reactions were examined. Infants' history of exposure to interparental conflict and infant reactive temperament were examined as moderators. A community sample of 74 infants, aged 6-14 months, participated with their parents. Behavioral observations were made of parents' marital conflict and…

  10. Spin-dependent observables in surrogate reactions

    CERN Document Server

    Chiba, Satoshi; Aritomo, Yoshihiro

    2011-01-01

    Observables emitted from various spin states in compound U nuclei are investigated to validate usefulness of the surrogate reaction method. It was found that energy spectrum of cascading $\\gamma$-rays and their multiplicities, spectrum of evaporated neutrons, and mass-distribution of fission fragments show clear dependence on the spin of decaying nuclei. The present results indicate that they can be used to infer populated spin distributions which significantly affect the decay branching ratio of the compound system produced by the surrogate reactions.

  11. An Experimental Study on Mitigating Alkali Silica Reaction by Using Fly Ash (FA) in Combination with Silica Fume and Expanded Perlite Powder (EPP)

    OpenAIRE

    Isneini Mohd; Sagawa Yasutaka; Hamada Hidenori; Yamamoto Daisuke

    2016-01-01

    ASR suppression by FA, SF, EPP, FA in combination with SF and EPP were evaluated by both mortar bar and concrete prism test. Mortar bars were made based on JIS A 1146, meanwhile concrete prism bars were casted in accordance with Rilem AAR-3. Both specimens were stored in 40°C 100% R.H. controlled room. Mortar and concrete mixtures used reactive aggregate in pessimum proportion. The results indicated that FA in combination with SF and EPP showed smaller expansion compared to FA. The best of co...

  12. An Experimental Study on Mitigating Alkali Silica Reaction by Using Fly Ash (FA in Combination with Silica Fume and Expanded Perlite Powder (EPP

    Directory of Open Access Journals (Sweden)

    Isneini Mohd

    2016-01-01

    Full Text Available ASR suppression by FA, SF, EPP, FA in combination with SF and EPP were evaluated by both mortar bar and concrete prism test. Mortar bars were made based on JIS A 1146, meanwhile concrete prism bars were casted in accordance with Rilem AAR-3. Both specimens were stored in 40°C 100% R.H. controlled room. Mortar and concrete mixtures used reactive aggregate in pessimum proportion. The results indicated that FA in combination with SF and EPP showed smaller expansion compared to FA. The best of concrete mixtures in reducing expansion is combination of FA with SF (FA15SF10.

  13. Basaltic rocks behavior of the Corrientes and Entre Rios province from the alcali silice reaction

    International Nuclear Information System (INIS)

    This work is about the basaltic rocks deposits in Mesopotamia - Argentina. This material is used for dikes, flooring and art . In several of them has been developed expansive processes associated with alkali - silica reaction such as pavements of some routes. In order to evaluate the behavior of these rocks their are obtained samples from the quarries using standard methods such as petrographic, rod accelerated and dissolved silica agree with the IRA M standards

  14. Observation of muon-electron pairs in neutrino reactions

    International Nuclear Information System (INIS)

    The present thesis describes the observation of muon-electron pairs in neutrino reactions. This experiment was performed using an optical multiplate spark chamber in the broad band neutrino beam of the CERN proton synchrotron. (orig.)

  15. Observation of Coherence in the Photosystem II Reaction Center

    CERN Document Server

    Fuller, Franklin D; Senlik, S Seckin; Wilcox, Daniel E; Ogilvie, Jennifer P

    2013-01-01

    Photosynthesis powers life on our planet. The basic photosynthetic architecture comprises antenna complexes to harvest solar energy and reaction centers to convert the energy into a stable charge separated state. In oxygenic photosynthesis, the initial charge separation event occurs in the photosystem II reaction center; the only known natural enzyme that uses solar energy to split water. Energy transfer and charge separation in photosynthesis are rapid and have high quantum efficiencies. Recently, nonlinear spectroscopic experiments have suggested that electronic coherence may play a role in energy transfer efficiency in antenna complexes. Here we report the observation of coherence in the photosystem II reaction center by two dimensional electronic spectroscopy. The frequencies of the observed coherences match exciton difference frequencies and/or known vibrational modes of the photosystem II reaction center. These observations raise questions about the possible role of electronic and/or vibrational coheren...

  16. Medium effects on spin observables of proton knockout reactions

    International Nuclear Information System (INIS)

    Medium modifications of the properties of bound nucleons and mesons are investigated by means of medium energy quasi free proton knockout reactions with polarized incident protons. The sensitivity of the spin observables of these reactions to modifications of the nucleon and meson properties is studied using the Bonn one-boson exchange model of the nucleon-nucleon interaction. A method proposed to extract the pp analysing power in medium from the (p, 2 p) asymmetries indicates a reduction of this quantity compared to its free space value. This reduction is linked to modifications of masses and coupling constants of the nucleons and mesons in the nucleus. The implications of these modifications for another spin observable to be measured in the future are discussed. (author). 39 refs, 9 figs

  17. Does observation of postural imbalance induce a postural reaction?

    Directory of Open Access Journals (Sweden)

    Banty Tia

    Full Text Available BACKGROUND: Several studies bring evidence that action observation elicits contagious responses during social interactions. However automatic imitative tendencies are generally inhibited and it remains unclear in which conditions mere action observation triggers motor behaviours. In this study, we addressed the question of contagious postural responses when observing human imbalance. METHODOLOGY/PRINCIPAL FINDINGS: We recorded participants' body sway while they observed a fixation cross (control condition, an upright point-light display of a gymnast balancing on a rope, and the same point-light display presented upside down. Our results showed that, when the upright stimulus was displayed prior to the inverted one, centre of pressure area and antero-posterior path length were significantly greater in the upright condition compared to the control and upside down conditions. CONCLUSIONS/SIGNIFICANCE: These results demonstrate a contagious postural reaction suggesting a partial inefficiency of inhibitory processes. Further, kinematic information was sufficient to trigger this reaction. The difference recorded between the upright and upside down conditions indicates that the contagion effect was dependent on the integration of gravity constraints by body kinematics. Interestingly, the postural response was sensitive to habituation, and seemed to disappear when the observer was previously shown an inverted display. The motor contagion recorded here is consistent with previous work showing vegetative output during observation of an effortful movement and could indicate that lower level control facilitates contagion effects.

  18. Does Observation of Postural Imbalance Induce a Postural Reaction?

    Science.gov (United States)

    Tia, Banty; Saimpont, Arnaud; Paizis, Christos; Mourey, France; Fadiga, Luciano; Pozzo, Thierry

    2011-01-01

    Background Several studies bring evidence that action observation elicits contagious responses during social interactions. However automatic imitative tendencies are generally inhibited and it remains unclear in which conditions mere action observation triggers motor behaviours. In this study, we addressed the question of contagious postural responses when observing human imbalance. Methodology/Principal Findings We recorded participants' body sway while they observed a fixation cross (control condition), an upright point-light display of a gymnast balancing on a rope, and the same point-light display presented upside down. Our results showed that, when the upright stimulus was displayed prior to the inverted one, centre of pressure area and antero-posterior path length were significantly greater in the upright condition compared to the control and upside down conditions. Conclusions/Significance These results demonstrate a contagious postural reaction suggesting a partial inefficiency of inhibitory processes. Further, kinematic information was sufficient to trigger this reaction. The difference recorded between the upright and upside down conditions indicates that the contagion effect was dependent on the integration of gravity constraints by body kinematics. Interestingly, the postural response was sensitive to habituation, and seemed to disappear when the observer was previously shown an inverted display. The motor contagion recorded here is consistent with previous work showing vegetative output during observation of an effortful movement and could indicate that lower level control facilitates contagion effects. PMID:21423622

  19. [Measurements of observables of pion-nucleon reactions]. Progress report

    International Nuclear Information System (INIS)

    This document reports the progress of the research of pion reactions. These include (1) a study to measure observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross section measurements at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π+- on 3H and 3He. Individual experiments will be indexed separately

  20. First observations of Pontecorvo reactions with a recoiling neutron

    Energy Technology Data Exchange (ETDEWEB)

    Amsler, C. [California Univ., Berkeley, CA (United States); Armstrong, D.S. [California Univ., Berkeley, CA (United States); Augustin, I. [California Univ., Berkeley, CA (United States); Baker, C.A. [California Univ., Berkeley, CA (United States); Barnett, B.M. [California Univ., Berkeley, CA (United States); Batty, C.J. [California Univ., Berkeley, CA (United States); Beuchert, K. [California Univ., Berkeley, CA (United States); Birien, P. [California Univ., Berkeley, CA (United States); Bluem, P. [California Univ., Berkeley, CA (United States); Bossingham, R. [California Univ., Berkeley, CA (United States); Braune, K. [California Univ., Berkeley, CA (United States); Brose, J. [California Univ., Berkeley, CA (United States); Bugg, D.V. [California Univ., Berkeley, CA (United States); Burchell, M. [California Univ., Berkeley, CA (United States); Case, T. [California Univ., Berkeley, CA (United States); Cooper, A. [California Univ., Berkeley, CA (United States); Cramer, O. [California Univ., Berkeley, CA (United States); Crowe, K.M. [California Univ., Berkeley, CA (United States); Degener, T. [California Univ., Berkeley, CA (United States); Dietz, H.P. [California Univ., Berkeley, CA (United States); Dombrowski, S. v.; Doser, M.; Duennweber, W.; Engelhardt, D.; Englert, M.; Faessler, M.A.; Felix, C.; Hackmann, R.; Haddock, R.P.; Heinsius, F.H.; Herz, M.; Hessey, N.P.; Hidas, P.; Illinger, P.; Jamnik, D.; Kalinowsky, H.; Kaemmle, B.; Kiel, T.; Kisiel, J.; Klempt, E.; Kobel, M.; Koch, H.; Kolo, C.; Koenigsmann, K.; Kuhn, J.; Kunze, M.; Lakata, M.; Landua, R.; Luedemann, J.; Matthaey, H.; Merkel, M.; Merlo, J.P.; Meyer, C.A.; Montanet, L.; Noble, A.; Ould-Saada, F.; Peters, K.; Pinder, C.N.; Pinter, G.; Ravndal, S.; Schaefer, E.; Schmidt, P.; Spanier, S.; Stoeck, H.; Strassburger, C.; Strohbusch, U.; Suffert, M.; Thoma, U.; Urner, D.; Voelcker, C.; Walter, F.; Walther, D.; Wiedner, U.; Winter, N.; Zoll, J.; Zou, B.S.; Zupancic, C.; Crystal Barrel ...

    1995-04-01

    We report the first observations of Pontecorvo reactions of the type pd {yields} Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR ( anti pd {yields} {pi}{sup 0}n) = (7.03 {+-} 0.72) x 10{sup -6}, BR ( anti pd {yields} {eta}n) = (3.19 {+-} 0.48) x 10{sup -6}, BR ( anti pd {yields} {omega}n) = (22.8 {+-} 4.1) x 10{sup -6}, BR ( anti pd {yields} {eta}`n) {<=} 14 x 10{sup -6} (at 95% confidence level). Assuming charge independence, our result for anti pd {yields} {pi}{sup 0}n is compatible with measurements of the only other observed Pontecorvo reaction anti pd {yields} {pi}{sup -}p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assuming N N annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV. (orig.)

  1. First observations of Pontecorvo reactions with a recoiling neutron

    International Nuclear Information System (INIS)

    We report the first observations of Pontecorvo reactions of the type pd → Xn. We fully reconstruct the outgoing meson and, for antiprotons stopped in liquid deuterium, we measure: BR ( anti pd → π0n) = (7.03 ± 0.72) x 10-6, BR ( anti pd → ηn) = (3.19 ± 0.48) x 10-6, BR ( anti pd → ωn) = (22.8 ± 4.1) x 10-6, BR ( anti pd → η'n) ≤ 14 x 10-6 (at 95% confidence level). Assuming charge independence, our result for anti pd → π0n is compatible with measurements of the only other observed Pontecorvo reaction anti pd → π-p. The experimental ratios between the above branching ratios are in fair agreement with both the statistical model and dynamical two-step models (assuming N N annihilation into two mesons, with subsequent absorption of one meson on the remaining nucleon). This agreement suggests that there may be appreciable rates for Pontecorvo reactions producing final state mesons with masses above 1 GeV. (orig.)

  2. In situ TEM observation of solid-gas reactions

    International Nuclear Information System (INIS)

    Under a gaseous atmosphere at high temperatures, almost all the materials (metal, catalysts, etc.) change their structures and properties. For the research and development of materials, it is of vital importance to clarify mechanisms of solid-gas and liquid-gas reactions. Recently an in situ TEM system combined with an environmental holder, which has a gas injection nozzle close to a specimen-heating element, has been developed. The gas injection nozzle permits gas to flow around the specimens sitting on the heating element made of a fine W filament. The newly developed in situ TEM has a differential pumping system; therefore, the pressure in the specimen chamber is maintained in the range of higher than 1 Pa, while the pressure in the electron gun chamber can be kept in the range of 10-5 Pa. This system was applied to in situ observation of chemical reactions of metals with gases: Observation of oxidation and reduction under a gas pressure ranging from 10-5 Pa to 1 Pa at high temperatures (room temperature to ∼1473 K) were successfully carried out on pure metal and rare metal catalysts at near-atomic resolution. This in situ environmental TEM system is promising for clarifying mechanisms of many solid-gas and liquid-gas reactions that take place at high temperatures under a gas atmosphere.

  3. Lithological influence of aggregate in the alkali-carbonate reaction

    International Nuclear Information System (INIS)

    The reactivity of carbonate rock with the alkali content of cement, commonly called alkali-carbonate reaction (ACR), has been investigated. Alkali-silica reaction (ASR) can also contribute in the alkali-aggregate reaction (AAR) in carbonate rock, mainly due to micro- and crypto-crystalline quartz or clay content in carbonate aggregate. Both ACR and ASR can occur in the same system, as has been also evidenced on this paper. Carbonate aggregate samples were selected using lithological reactivity criteria, taking into account the presence of dedolomitization, partial dolomitization, micro- and crypto-crystalline quartz. Selected rocks include calcitic dolostone with chert (CDX), calcitic dolostone with dedolomitization (CDD), limestone with chert (LX), marly calcitic dolostone with partial dolomitization (CD), high-porosity ferric dolostone with clays (FD). To evaluate the reactivity, aggregates were studied using expansion tests following RILEM AAR-2, AAR-5, a modification using LiOH AAR-5Li was also tested. A complementary study was done using petrographic monitoring with polarised light microscopy on aggregates immersed in NaOH and LiOH solutions after different ages. SEM-EDAX has been used to identify the presence of brucite as a product of dedolomitization. An ACR reaction showed shrinkage of the mortar bars in alkaline solutions explained by induced dedolomitization, while an ASR process typically displayed expansion. Neither shrinkage nor expansion was observed when mortar bars were immersed in solutions of lithium hydroxide. Carbonate aggregate classification with AAR pathology risk has been elaborated based on mechanical behaviours by expansion and shrinkage. It is proposed to be used as a petrographic method for AAR diagnosis to complement the RILEM AAR1 specifically for carbonate aggregate. Aggregate materials can be classified as I (non-reactive), II (potentially reactive), and III (probably reactive), considering induced dedolomitization ACR

  4. Observation of incomplete fusion reactions at l < l {sub crit}

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Abhishek, E-mail: abhishekyadav117@gmail.com; Sharma, Vijay R., E-mail: abhishekyadav117@gmail.com; Singh, Devendra P., E-mail: abhishekyadav117@gmail.com; Unnati,; Singh, B. P.; Prasad, R. [Department of Physics, Aligarh Muslim University, Aligarh (UP) - 202 002 (India); Singh, Pushpendra P. [GSI-Helmholtz Centre for Heavy Ion Research GmbH, D-64291 Darmstadt (Germany); Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P. [NP-Group: Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi - 110 067 (India); Sharma, M. K. [Department of Physics, S. V. College, Aligarh- 202 001 (India)

    2014-08-14

    In order to understand the presence of incomplete fusion at low energies i.e. 4-7MeV/nucleon and also to study its dependence on various entrance-channel parameters, the two type of measurements (i) excitation function for {sup 12}C+{sup 159}Tb, and (ii) forward recoil ranges for {sup 12}C+{sup 159}Tb systems have been performed. The experimentally measured excitation functions have been analyzed within the framework of compound nucleus decay using statistical model code PACE4. Analysis of data suggests the production of xn/px)n-channels via complete fusion, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of α-emitting channels has been observed over the theoretical ones, which has been attributed due to the incomplete fusion processes. Further, the incomplete fusion events observed in case of forward recoil range measurements have been explained on the basis of the breakup fusion model, where these events may be attributed to the fusion of {sup 8}Be and/or {sup 4}He from {sup 12}C projectile to the target nucleus. In the present work, the SUMRULE model calculations are found to highly underestimate the observed incomplete fusion cross-sections which indicate that the l-values lower than l {sub crit} (limit of complete fusion) significantly contribute to the incomplete fusion reactions.

  5. Staff Reactions to Challenging Behaviour: An Observation Study

    Science.gov (United States)

    Lambrechts, Greet; Van Den Noortgate, Wim; Eeman, Lieve; Maes, Bea

    2010-01-01

    Staff reactions play an important role in the development and maintaining of clients' challenging behaviour. Because there is a paucity of research on staff reactions in naturalistic settings, this study examined sequential associations between challenging behaviour and staff reactions by means of a descriptive analysis. We analysed video…

  6. Observation of Coherence in the Photosystem II Reaction Center

    OpenAIRE

    Fuller, Franklin D; Pan, Jie; Senlik, S. Seckin; Wilcox, Daniel E.; Ogilvie, Jennifer P.

    2013-01-01

    Photosynthesis powers life on our planet. The basic photosynthetic architecture comprises antenna complexes to harvest solar energy and reaction centers to convert the energy into a stable charge separated state. In oxygenic photosynthesis, the initial charge separation event occurs in the photosystem II reaction center; the only known natural enzyme that uses solar energy to split water. Energy transfer and charge separation in photosynthesis are rapid and have high quantum efficiencies. Rec...

  7. A competitive reaction observed during fluorination of FHPG and FHBG

    International Nuclear Information System (INIS)

    The 18F-labelling yield of the tracers [18F]FHBG and [18F]FHPG, which is used to monitor the gene expression of HSV-1 TK, is reduced by competitive reactions. In the synthesis of the reference standards the by-products were isolated and analysed. (orig.)

  8. The accelerated observer with back-reaction effects

    OpenAIRE

    R. CasadioDept. of Phys. and INFN, Bologna, Italy; Venturi, G.

    2015-01-01

    The quantum mechanical evolution of an accelerated extended detector coupled to a massless scalar field is exhibited and the back-reaction due to emission or absorption processes computed at first order in the change of the detector's mass and acceleration. An analogy with black hole evaporation is found and illustrated.

  9. Use of mineral additions for the inhibition of internal expansive reactions in concrete structures : Good and bad synergies

    OpenAIRE

    Santos Silva, A.; BETTENCOURT RIBEIRO, A; Jalali, S; Divet, Loïc

    2008-01-01

    Several studies have been performed along the last few years related with the use of fly ash in the suppression of expansion due to alkali-silica reaction (ASR). However, relatively little attention has been focused in its effectiveness to control the delayed ettringite formation (DEF) in hardened concrete, and the use of metakaolin to control the ASR and DEF. The research work presented in this paper deals with the influence of fly ash (FA) and metakaolin (MK) in the inhibition of ASR and DE...

  10. A new state of nuclear matter observed in transfer reactions

    International Nuclear Information System (INIS)

    The cross section curves for the formation, at the barrier, of trans-target isotopes of a heavy element by bombardment of a heavy target with various heavy ions, and those for the formation of isotopes of a superheavy element by complete fusion projectile and target, both are similar to the distribution of the neutron number N of a fission fragment around its most probable value. This situation suggests that nucleons are transferred according to one and the same law in the fission reaction and in the transfer reactions: This law results from the creation of a new state of nuclear matter, having a lifetime of only 0.17 yoctosecond, and causing uncertainties in the neutron number N of the product amounting to 2.54 atomic mass unit, as measured by J. Terrell in his study of the prompt neutron emission.

  11. Strangeness suppression of qq creation observed in exclusive reactions.

    Science.gov (United States)

    Mestayer, M D; Park, K; Adhikari, K P; Aghasyan, M; Pereira, S Anefalos; Ball, J; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; Deur, A; Djalali, C; Doughty, D; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fleming, J A; Forest, T A; Garillon, B; Garçon, M; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gothe, R W; Griffioen, K A; Guegan, B; Guidal, M; Hakobyan, H; Hanretty, C; Hattawy, M; Holtrop, M; Hughes, S M; Hyde, C E; Ilieva, Y; Ireland, D G; Jiang, H; Jo, H S; Joo, K; Keller, D; Khandaker, M; Kim, A; Kim, W; Koirala, S; Kubarovsky, V; Kuleshov, S V; Lenisa, P; Levine, W I; Livingston, K; Lu, H Y; MacGregor, I J D; Mayer, M; McKinnon, B; Meyer, C A; Mirazita, M; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Pappalardo, L L; Paremuzyan, R; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Protopopescu, D; Puckett, A J R; Raue, B A; Rimal, D; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Saini, M S; Schott, D; Schumacher, R A; Simonyan, A; Sokhan, D; Strauch, S; Sytnik, V; Tang, W; Tian, Ye; Ungaro, M; Vernarsky, B; Vlassov, A V; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Weinstein, L B; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W; Zonta, I

    2014-10-10

    We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production. PMID:25375706

  12. Estimation of the reaction rate constant of HOCl by SMILES observation

    Science.gov (United States)

    Kuribayashi, Kouta; Kasai, Yasuko; Sato, Tomohiro; Sagawa, Hideo

    2012-07-01

    Hypochlorous acid, HOCl plays an important role to link the odd ClOx and the odd HOx in the atmospheric chemistry with the reaction: {ClO} + {HO_{2}} \\longrightarrow {HOCl} + {O_{2}} Quantitative understanding of the rate constant of the reaction (1.1) is essential for understanding the ozone loss in the mid-latitude region because of a view point of its rate controlling role in the ozone depletion chemistry. Reassessment of the reaction rate constant was pointed out from MIPAS/Envisat observations (von Clarmann et al., 2011) and balloon-borne observations (Kovalenko et al., 2007). Several laboratory studies had been reported, although the reaction rate constants have large uncertainties, as k{_{HOCl}} = (1.75 ± 0.52) × 10^{-12} exp[(368 ± 78)/T] (Hickson et al., 2007), and large discrepancies (Hickson et al., 2007;Stimpfle et al., 1979). Moreover, theoretical ab initio studies pointed out the pressure dependence of the reaction (1.1) (Xu et al., 2003). A new high-sensitive remote sensing technology named Superconducting SubMillimeter-wave Limb-Emission Sounder (SMILES) on the International Space Station (ISS) had observed diurnal variations of HOCl in the upper stratosphere/lower mesosphere (US/LM) region for the first time. ClO and HO_{2} were slso observed simultaneously with HOCl. SMILES performed the observations between 12^{{th}} October 2009 and 21^{{th}} April 2010. The latitude coverage of SMILES observation is normally 38°S-65°N. The altitude region of HOCl observation is about 28-70 km. We estimated the time period in which the reaction (1.1) becomes dominant in the ClO_{y} diurnal chemistry in US/LM. The reaction rate constant was directly estimated by decay of [ClO] and [HO_{2}] amounts in that period. The derived reaction rate constant represented well the increase of [HOCl] amount.

  13. Weight-Based Victimization toward Overweight Adolescents: Observations and Reactions of Peers

    Science.gov (United States)

    Puhl, Rebecca M.; Luedicke, Joerg; Heuer, Cheslea

    2011-01-01

    Background: Weight-based victimization has become increasingly reported among overweight youth, but little is known about adolescents' perceptions and observations of weight-based teasing and bullying. This study examined adolescents' observations of and reactions to weight-based victimization toward overweight students at school. Methods:…

  14. First observation of a superdeformed nucleus produced in an α x n reaction channel

    International Nuclear Information System (INIS)

    Recent data from the EUROGAM array have revealed the population of the yrast superdeformed (SD) band of 192Hg in the α4n exit channel of the 16O+184W reaction at 113 MeV beam energy. The nucleus assignment was made on the basis of the SD band transition energies, and the observation of characteristic X-rays and low-lying yrast γ-transition of 192Hg in coincidence with the SD band γ-rays. Both the feeding and decay-out patterns of the observed SD band have been found similar to the ones previously measured in the (36S, 4n) reaction. (orig.)

  15. A Luenberger observer for reaction-diffusion models with front position data

    Science.gov (United States)

    Collin, Annabelle; Chapelle, Dominique; Moireau, Philippe

    2015-11-01

    We propose a Luenberger observer for reaction-diffusion models with propagating front features, and for data associated with the location of the front over time. Such models are considered in various application fields, such as electrophysiology, wild-land fire propagation and tumor growth modeling. Drawing our inspiration from image processing methods, we start by proposing an observer for the eikonal-curvature equation that can be derived from the reaction-diffusion model by an asymptotic expansion. We then carry over this observer to the underlying reaction-diffusion equation by an "inverse asymptotic analysis", and we show that the associated correction in the dynamics has a stabilizing effect for the linearized estimation error. We also discuss the extension to joint state-parameter estimation by using the earlier-proposed ROUKF strategy. We then illustrate and assess our proposed observer method with test problems pertaining to electrophysiology modeling, including with a realistic model of cardiac atria. Our numerical trials show that state estimation is directly very effective with the proposed Luenberger observer, while specific strategies are needed to accurately perform parameter estimation - as is usual with Kalman filtering used in a nonlinear setting - and we demonstrate two such successful strategies.

  16. Real-time observations of lithium battery reactions-operando neutron diffraction analysis during practical operation.

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-01-01

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries. PMID:27357605

  17. [Nobody wants to lose a child--nurses' observations of family reactions].

    Science.gov (United States)

    de Souza, L J; Barroso, M G

    1997-01-01

    The presence of veterinary products in the houses without any minimum security procedures has led to a poisoning case for a one-year old child who developed a serious systemic reaction. This child was interned at a Pediatric Intensive Care Unit at a public hospital in Fortaleza, Ceara. This study aims at identifying the family reaction facing a poisoning of a child and analyzing these reactions, interpreting its social cultural context. It has been developed as an ethnographic study case, consisting of the exploration, decision and discovery phases. It has been observed through the results that the family recognizes the existence of risk factors in home environment but does not adopt any coherent preventive methods with this experience. We do believe that these occurrences reduction demand transforming educative actions which may lead the family to be conscious towards the problematic that concerns poisoning for children, occurred under their responsibility. PMID:10765334

  18. First observation of a superdeformed nucleus produced in an [alpha] x n reaction channel

    Energy Technology Data Exchange (ETDEWEB)

    Duprat, J.; Gall, B.J.P.; Porquet, M.G.; Hannachi, F.; Azaiez, F.; Aiche, M.; Bastin, G.; Beausang, C.W.; Beraud, R.; Bourgeois, C.; Clark, R.M.; Deloncle, I.; Duffait, R.; Hauschild, K.; Huebel, H.; Joyce, M.J.; Kaci, M.; Korichi, A.; Coz, Y. le; Meyer, M.; Paul, E.S.; Perrin, N.; Poffe, N.; Redon, N.; Schueck, C.; Sergolle, H.; Sharpey-Schafer, J.F.; Simpson, J.; Smith, A.G.; Wadsworth, R. (Inst. de Physique Nucleaire, 91 Orsay (France) C.S.N.S.M., IN2P3-CNRS, 91 Orsay (France) Oliver Lodge Lab., Univ. of Liverpool (United Kingdom) Inst. de Physique Nucleaire, CNRS-IN2P3, 69 Villeurbanne (France) Univ. of York, Dept. of Physics, Helsington (United Kingdom) Inst. fuer Kernphysik der Univ., Bonn (Germany) Univ. of Oxford, Dept. of Physics (United Kingdom) SERC, Daresbury Lab., Warrington (United Kingdom) Schuster Lab., Univ. of Manchester (United Kingdom))

    1994-07-01

    Recent data from the EUROGAM array have revealed the population of the yrast superdeformed (SD) band of [sup 192]Hg in the [alpha]4n exit channel of the [sup 16]O+[sup 184]W reaction at 113 MeV beam energy. The nucleus assignment was made on the basis of the SD band transition energies, and the observation of characteristic X-rays and low-lying yrast [gamma]-transition of [sup 192]Hg in coincidence with the SD band [gamma]-rays. Both the feeding and decay-out patterns of the observed SD band have been found similar to the ones previously measured in the ([sup 36]S, 4n) reaction. (orig.)

  19. Comment on "Observation of neutronless fusion reactions in picosecond laser plasmas".

    Science.gov (United States)

    Kimura, S; Anzalone, A; Bonasera, A

    2009-03-01

    The paper by Belyaev [Phys. Rev. E 72, 026406 (2005)] reported the first experimental observation of alpha particles produced in the thermonuclear reaction 11B(p,alpha)8Be induced by laser irradiation on a 11B polyethylene (CH2) composite target. The laser used in the experiment is characterized by a picosecond pulse duration and a peak of intensity of 2x10(18) W/cm(2). We suggest that both the background-reduction method adopted in their detection system and the choice of the detection energy region of the reaction products are possibly inadequate. Consequently the total yield reported underestimates the true yield. Based on their observation, we give an estimation of the total yield to be higher than their conclusion, i.e., of the order of 10(5)alpha per shot. PMID:19392090

  20. Comment on "Observation of neutronless fusion reactions in picosecond laser plasmas"

    CERN Document Server

    Kimura, S; Bonasera, A

    2008-01-01

    The paper by Belyaev et al.[Phys. Rev. E 72, 026406 (2005)] has reported the first experimental observation of alpha particles resulted from the thermonuclear reaction $^{11}$B($p,\\alpha$)$^{8}$Be induced by laser-irradiation on a $^{11}$B polyethylene (CH$_2$) composite target. The laser utilized in the experiment is characterized by the picosecond pulse duration and the peak intensity 2$\\times10^{18}$ W/cm$^2$. We suggest that both the background-reduction method adopted in their detection system and the choice of the detection energy region of the reaction products are possibly inadequate. Consequently the total yield reported underestimates the genuine yield. Based on their observation, we give an estimation of the total yield to be higher than their conclusion, i.e., of the order of 10$^5 \\alpha$ per shot.

  1. Direct observation of ultrafast-electron-transfer reactions unravels high effectiveness of reductive DNA damage

    OpenAIRE

    Nguyen, Jenny; Ma, Yuhan; Luo, Ting; Bristow, Robert G; Jaffray, David A; Lu, Qing-Bin

    2011-01-01

    Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosec...

  2. Ultrafast electron diffraction and direct observation of transient structures in a chemical reaction

    OpenAIRE

    Cao, Jianming; Ihee, Hyotcherl; Zewail, Ahmed H.

    1999-01-01

    Ultrafast electron diffraction is a unique method for the studies of structural changes of complex molecular systems. In this contribution, we report direct ultrafast electron diffraction study of the evolution of short-lived intermediates in the course of a chemical change. Specifically, we observe the transient intermediate in the elimination reaction of 1,2-diiodotetrafluoroethane (C2F4I2) to produce the corresponding ethylene derivative by the breakage of two carbon-iodine, C---I, bonds. ...

  3. Prospective Observational Study of Adverse Drug Reactions of Anticancer Drugs Used in Cancer Treatment in a Tertiary Care Hospital

    OpenAIRE

    V. K. Saini; Sewal, R. K.; Ahmad, Yusra; B Medhi

    2015-01-01

    Adverse drug reactions associated with the use of anticancer drugs are a worldwide problem and cannot be ignored. Adverse drug reactions can range from nausea, vomiting or any other mild reaction to severe myelosuppression. The study was planned to observe the suspected adverse drug reactions of cancer chemotherapy in patients aged >18 years having cancer attending Postgraduate Institute of Medical Education and Research, Chandigarh. During the study period, 101 patients of breast cancer and ...

  4. How to identify carbonate rock reactions in concrete

    International Nuclear Information System (INIS)

    This paper summarizes the modern petrographic techniques used to diagnose carbonate rock reactions in concrete. Concrete microbar specimens of the prototype RILEM AAR-5 test, provided by the Austrian Cement Research Institute, and typical Canadian concrete that had undergone alkali-carbonate reaction (ACR) were examined. Scanning electron microscopy, element mapping and quantitative analysis using electron-probe microanalyzer with energy-dispersive spectrometry (EPMA/EDS: around x 2000, <0.1 nA) were made of polished thin sections after completing polarizing microscopy. Dedolomitization produced a myrmekitic texture, composed of spotted brucite (<3 μm) and calcite within the reaction rim, along with a carbonate halo of calcite in the surrounding cement paste. However, no evidence was detected that dedolomitization had produced the expansion cracks in the cement paste, while the classical definition of alkali-carbonate reaction postulates their development. It was found that the alkali-silica reaction (ASR) due to cryptocrystalline quartz hidden in the matrix, always associated with dedolomitization in all the carbonate aggregates tested, was responsible for the expansion of both the laboratory and field concretes, even with the Canadian dolomitic limestone from Kingston, the reference material for alkali-carbonate reaction. It is suggested that the term alkali-carbonate reaction is misleading

  5. Observation of the Helium 7 {Lambda} hypernucleus by the (e,e'K+) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Satoshi; Okayasu, Yuichi; Seva, Tomislav; Rodriguez, Victor; Baturin, Pavlo; Yuan, Lulin; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, Oliver; Benmokhtar, Fatiha; Boeglin, Wener; Bosted, Peter; Carlini, Roger; Chen, Chunhua; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, Aji; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Toshiyuki, Gogami; Gueye, Paul; Han, Yuncheng; Hashimoto, Osamu; Hiyama, E; Honda, D; Horn, Tanja; Hu, Bitao; Hungerford, Ed; Jayalath, Chandana; Jones, Mark; Johnston, Kathleen; Kalantarians, Narbe; Kanda, Hiroki; Kaneta, M; Kato, Seigo; Kato, Shigeki; Kawama, Daisuke; Keppel, Cynthia; Kramer, Laird; Lan, Kejian; Luo, Wei; Mack, David; Maeda, Kazushige; Malace, Simona; Margaryan, Amur; Marikyan, Gagik; Markowitz, Pete; Maruta, Tomofumi; Maruyama, Nayuta; Miyoshi, Toshinuobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Nagao, Sho; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nonaka, Kenichi; Ohtani, Atsushi; Oyamada, Masamichi; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Raue, Brian; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Sato, Yoshinori; Segbefia, Edwin; Simicevic, Neven; Smith, Gregory; Song, Yushou; Sumihama, Mizuki; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tang, Liguang; Tsukada, Kyo; Tvaskis, Vladas; Vulcan, William; Wells, Steven; Wood, Stephen; Yan, Chen

    2013-01-01

    An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 {Lambda}, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The He 7 {Lambda} binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of {Lambda} N potential.

  6. Comment on "Observation of neutronless fusion reactions in picosecond laser plasmas"

    OpenAIRE

    Kimura, S.; Anzalone, A.; Bonasera, A.

    2008-01-01

    The paper by Belyaev et al. [Phys. Rev. E {\\bf 72}, 026406 (2005)] reported the first experimental observation of alpha particles produced in the thermonuclear reaction $^{11}$B($p,\\alpha$)$^{8}$Be induced by laser-irradiation on a $^{11}$B polyethylene (CH$_2$) composite target. The laser used in the experiment is characterized by a picosecond pulse duration and a peak of intensity of 2$\\times10^{18}$ W/cm$^2$. We suggest that both the background-reduction method adopted in their detection s...

  7. Feasibility study of observing η' mesic nuclei with (p,d) reaction

    International Nuclear Information System (INIS)

    A novel method is proposed to measure η'(958) meson bound states in 11C nuclei by missing mass spectroscopy of the 12C (p,d) reaction near the η' production threshold. It is shown that peak structures will be observed experimentally in an inclusive measurement in case that the in-medium η' mass reduction is sufficiently large and that the decay width of η' mesic states is narrow enough. Such a measurement will be feasible with the intense proton beam supplied by the SIS synchrotron at GSI combined with the good energy resolution of the fragment separator FRS. (author)

  8. Reaction-diffusion patterns: From observations in halogene chemistry to a test for implication in mitosis

    Science.gov (United States)

    Dulos, E.; Hunding, A.; Boissonade, J.; de Kepper, P.

    Since the seminal paper "The chemical basis of morphogenesis" by Alan Turing, the temporal and spatial self-organization phenomena produced in chemically reacting and diffusing systems are often thought as paradigms for biological development. The basic theoretical principles on which the development of stationary concentration patterns (Turing structures) rely on are briefly presented. We review different aspects of our contribution to the experimental observation of reaction-diffusion patterns in iodine-oxychlorine systems. The experimental techniques are emphasized. Phase diagrams gathering different standing and travelling patterns are presented, analyzed and modeled. A special attention is also given to some peculiar pattern growth dynamics (spot division, finger splitting).

  9. Direct observation of ultrafast-electron-transfer reactions unravels high effectiveness of reductive DNA damage.

    Science.gov (United States)

    Nguyen, Jenny; Ma, Yuhan; Luo, Ting; Bristow, Robert G; Jaffray, David A; Lu, Qing-Bin

    2011-07-19

    Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (e(pre)-), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. e(pre)- is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosecond time-resolved laser spectroscopy measurements of ultrafast-electron-transfer (UET) reactions of e(pre)- with various scavengers (KNO(3), isopropanol, and dimethyl sulfoxide) and the first gel electrophoresis measurements of DNA strand breaks induced by e(pre)- and OH(•) radicals co-produced by two-UV-photon photolysis of water. We strikingly found that the yield of reductive DNA strand breaks induced by each e(pre)- is twice the yield of oxidative DNA strand breaks induced by each OH(•) radical. Our results not only unravel the long-standing mystery about the relative role of radicals in inducing DNA damage under ionizing radiation, but also challenge the conventional notion that oxidative damage is the main pathway for DNA damage. The results also show the potential of femtomedicine as a new transdisciplinary frontier and the broad significance of UET reactions of e(pre)- in many processes in chemistry, physics, biology, and the environment. PMID:21730183

  10. In-situ observations of catalytic surface reactions with soft x-rays under working conditions

    Science.gov (United States)

    Toyoshima, Ryo; Kondoh, Hiroshi

    2015-03-01

    Catalytic chemical reactions proceeding on solid surfaces are an important topic in fundamental science and industrial technologies such as energy conversion, pollution control and chemical synthesis. Complete understanding of the heterogeneous catalysis and improving its efficiency to an ultimate level are the eventual goals for many surface scientists. Soft x-ray is one of the prime probes to observe electronic and structural information of the target materials. Most studies in surface science using soft x-rays have been performed under ultra-high vacuum conditions due to the technical limitation, though the practical catalytic reactions proceed under ambient pressure conditions. However, recent developments of soft x-ray based techniques operating under ambient pressure conditions have opened a door to the in-situ observation of materials under realistic environments. The near-ambient-pressure x-ray photoelectron spectroscopy (NAP-XPS) using synchrotron radiation enables us to observe the chemical states of surfaces of condensed matters under the presence of gas(es) at elevated pressures, which has been hardly conducted with the conventional XPS technique. Furthermore, not only the NAP-XPS but also ambient-pressure compatible soft x-ray core-level spectroscopies, such as near-edge absorption fine structure (NEXAFS) and x-ray emission spectroscopy (XES), have been significantly contributing to the in-situ observations. In this review, first we introduce recent developments of in-situ observations using soft x-ray techniques and current status. Then we present recent new findings on catalytically active surfaces using soft x-ray techniques, particularly focusing on the NAP-XPS technique. Finally we give a perspective on the future direction of this emerging technique.

  11. Giant dipole resonance in 17O observed with the (γ,p) reaction

    International Nuclear Information System (INIS)

    The giant dipole resonance (GDR) in 17O has been studied with the reaction 17O(γ,p)16N from Eγ=13.50 to 43.15 MeV using quasimonoenergetic photons. The measured cross section shows major peaks at 15.1, 18.1, 19.3, 20.3, 22.2, 23.1, 24.4, and ∼26.5 MeV. The intermediate structure in the main GDR region is remarkably similar to that observed in 16O, indicating that the valence neutron outside the doubly magic 16O core perturbs the core-excited states minimally, in support of the weak-coupling hypothesis. We correlate the trends in GDR structure of 16,17,18O with changes in ground-state properties related to static deformation. The (γ,p) reaction selects strength predominantly from two-particle--one-hole configurations formed via E1 transitions from the 1p1/2 subshell; comparison with other reactions (photoneutron and radiative capture) provides information on the microscopic structure of E1 states. The peak observed near threshold at 15.1 MeV is remarkably strong; we infer that it originates from photoexcitation of a few narrow T=3/2 states and that M1 transitions contribute to the measured strength. The total absorption cross section is approximated by summing the (γ,p) cross section and the previously published photoneutron cross section; comparison with particle-hole shell-model calculations shows that the main cross-section features, including isospin distribution, are well predicted. Evidence is found for isospin splitting in 17O. Systematics of the integrated cross sections for the carbon, nitrogen, and oxygen isotopes are delineated

  12. Drug reaction with eosinophilia and systemic symptoms: Observations from a tertiary care institution

    Directory of Open Access Journals (Sweden)

    Sarita Sasidharanpillai

    2014-01-01

    Full Text Available Background: Drug reaction with eosinophilia and systemic symptoms (DRESS is a severe drug reaction which can mimic a viral infection, an autoimmune disease or a neoplastic disease. Aims: To study the clinical and epidemiological aspects of DRESS and to identify the precipitating drugs. Methods: All patients admitted to the dermatology ward of our tertiary care hospital from 1 st October 2010 to 30 th September 2013 with probable or definite DRESS as per the RegiSCAR scoring system were included in this prospective study. The clinical manifestations observed in the study population were studied and the common offending drugs were identified. Results: During the 3 year study period, 26 patients fulfilled criteria for probable or definite DRESS. In more than 50% of cases, the culprit drug was phenytoin. Most common symptoms observed were fever, rash and facial edema. Liver was the most common internal organ affected. Most of the patients responded to withdrawal of the drug and administration of steroids for 3-6 weeks. One patient with dapsone-induced DRESS died. Conclusions: Intense facial erythema and edema and an elevated eosinophil count were not found to be bad prognostic factors. In most instances the flare ups during the course of the disease could be managed with a slower tapering of steroids. More prospective studies on DRESS are required to assess the prognostic factors and to formulate better diagnostic criteria.

  13. Observations of parent reactions to sex-stereotyped behaviors: age and sex effects.

    Science.gov (United States)

    Fagot, B I; Hagan, R

    1991-06-01

    To examine differential socialization of boys and girls by mothers and fathers, home observations were completed for families of 92 12-month-old children, 82 18-month-old children, and 172 5-year-old children. Mothers gave more instructions and directions than did fathers, while fathers spent more time in positive play interaction. Differences in parents' reactions to 12- and 18-month boys and girls were as expected, with the exception that boys received more negative comment for communication attempts than did girls. The suggestion in the literature that fathers would be more involved in sex typing than mothers was not confirmed in this study. The only 2 significant sex-of-parent x sex-of-child effects occurred at 18 months; fathers gave fewer positive reactions to boys engaging in female-typical toy play, and mothers gave more instruction to girls when they attempted to communicate. We argue that the second year of life is the time when children are learning many new skills and when parents are still experimenting with parenting styles and may well use stereotypical responses when unsure of themselves. PMID:1914629

  14. Observation of multiprong events in U+Bi reaction using CR-39 polycarbonate

    International Nuclear Information System (INIS)

    Using CR-39 (C12 H18 O7) as a track detector, we have studied the interactions of 10 MeV/u and 13.7 MeV/u uranium ions with bismuth targets. The main objective of this study was to establish the viability of using a highly sensitive medium as nuclear track detector for the investigation of nuclear heavy ion reactions. We have carefully looked at the characteristics of tracks formed in CR-39 by plotting the frequency distributions of track lengths and angles, in the case of two and three-body channels. Cross-sections for ternary and quarternary events have been calculated for each energy and the total reaction cross-sections have been compared with the theoretical predictions. With uranium as projectile, it has been observed that a substantial number of binary events have their origin well inside the body of the detector. We have compared the angular correlation of these events with those of surface binary events and have found that they lie in quite different categories. Also, the separation of elastic events from the total set of surface binary events has been made. (author)

  15. Combining Bayesian methods and aircraft observations to constrain the HO. + NO2 reaction rate

    Directory of Open Access Journals (Sweden)

    A. G. Carlton

    2011-08-01

    Full Text Available Tropospheric ozone is the third strongest greenhouse gas, and has the highest uncertainty in radiative forcing of the top five greenhouse gases. Throughout the troposphere, ozone is produced by radical oxidation of nitrogen oxides (NOx = NO + NO2. In the upper troposphere (8–10 km, current chemical transport models under-estimate nitrogen dioxide (NO2 observations. Improvements to simulated NOx emissions from lightning have increased NO2 predictions, but the predictions in the upper troposphere remain biased low. The upper troposphere has low temperatures (T 2 and radicals, is currently over-estimated by 22 % in the upper troposphere. The results from this study suggest that the temperature sensitivity of nitric acid formation is lower than currently recommended. Since the formation of nitric acid removes nitrogen dioxide and radicals that drive the production of ozone, the revised reaction rate will affect ozone concentrations in upper troposphere impacting climate and air quality in the lower troposphere.

  16. Combining Bayesian methods and aircraft observations to constrain the HO. + NO2 reaction rate

    Directory of Open Access Journals (Sweden)

    A. G. Carlton

    2012-01-01

    Full Text Available Tropospheric ozone is the third strongest greenhouse gas, and has the highest uncertainty in radiative forcing of the top five greenhouse gases. Throughout the troposphere, ozone is produced by radical oxidation of nitrogen oxides (NOx = NO + NO2. In the upper troposphere (8–10 km, current chemical transport models under-estimate nitrogen dioxide (NO2 observations. Improvements to simulated NOx production from lightning have increased NO2 predictions, but the predictions in the upper troposphere remain biased low. The upper troposphere has low temperatures (T 2 and radicals, is currently over-estimated by 22% in the upper troposphere. The results from this study suggest that the temperature sensitivity of nitric acid formation is lower than currently recommended. Since the formation of nitric acid removes nitrogen dioxide and radicals that drive the production of ozone, the revised reaction rate will affect ozone concentrations in upper troposphere impacting climate and air quality in the lower troposphere.

  17. Atomic-scale observation of lithiation reaction front in nanoscale SnO 2 materials

    KAUST Repository

    Nie, Anmin

    2013-07-23

    In the present work, taking advantage of aberration-corrected scanning transmission electron microscopy, we show that the dynamic lithiation process of anode materials can be revealed in an unprecedented resolution. Atomically resolved imaging of the lithiation process in SnO2 nanowires illustrated that the movement, reaction, and generation of b = [1Ì...1Ì...1] mixed dislocations leading the lithiated stripes effectively facilitated lithium-ion insertion into the crystalline interior. The geometric phase analysis and density functional theory simulations indicated that lithium ions initial preference to diffuse along the [001] direction in the {200} planes of SnO2 nanowires introduced the lattice expansion and such dislocation behaviors. At the later stages of lithiation, the Li-induced amorphization of rutile SnO2 and the formation of crystalline Sn and LixSn particles in the Li2O matrix were observed. © 2013 American Chemical Society.

  18. What happens when iron becomes wet? Observation of reactions at interfaces between liquid and metal surfaces

    CERN Document Server

    Kimura, M

    2003-01-01

    Synchrotron-radiation has been applied to investigation of interfaces between liquid and metal surfaces, with a special attention to corrosion. Three topics are shown: (1) nano structures of rusts formed on steel after atmospheric corrosion. Evolution of 'Fe(O, OH) sub 6 network' is the key to understand how the durable rusts prevent from formation of more rusts. (2) In situ observation of reactions at the interface has been carried out for localized corrosion of stainless steel. It is shown that change in states of Cr sup 3 sup + and Br sup - ions near the interface is deeply related with a breakout of the passivation film. (3) A structural phase transformation on a Cu sub 3 Au(001) surface was investigated. Ordering remains even at a temperature higher than the bulk-critical temperature, showing surface-induced ordering. These approaches gives us crucial information for a new steel-product. (author)

  19. Evidence of tensor interactions in 16O observed via (p,d reaction

    Directory of Open Access Journals (Sweden)

    Ong H. J.

    2014-03-01

    Full Text Available We measured the differential cross sections of the 16O(p,d reaction populating the ground state and several low-lying excited states in 15O using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP, Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s. The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions.

  20. Medium Modi cation on Vector Mesons Observed in 12 GeV p + A Reactions

    International Nuclear Information System (INIS)

    The invariant mass spectra of e+e- pairs produced in 12 GeV p+A reactions are measured at the KEK-PS. We observed a significant enhancement over the known hadronic sources on the low-mass side of the ω meson peak. The 95 % C.L. allowed parameter regions for ρ/ω ratio are obtained as ρ/ω < 0.15 and ρ/ω < 0.31 for C and Cu targets, respectively. As for the φ meson, the data obtained with a Cu target revealed a significant excess on the low-mass side of the φ meson peak mainly in the βγφ < 1.25 region

  1. Medium Modi cation on Vector Mesons Observed in 12 GeV p + A Reactions

    Science.gov (United States)

    Naruki, M.; En'yo, H.; Muto, R.; Tabaru, T.; Yokkaichi, S.; Fukao, Y.; Funahashi, H.; Ishino, M.; Kanda, H.; Kitaguchi, M.; Mihara, S.; Miwa, K.; Miyashita, T.; Murakami, T.; Nakura, T.; Sakuma, F.; Togawa, M.; Yamada, S.; Yoshimura, Y.; Chiba, J.; Ieiri, M.; Sasaki, O.; Sekimoto, M.; Tanaka, K. H.; Hamagaki, H.; Kek-Ps E325 Collaboration

    2006-11-01

    The invariant mass spectra of e+e- pairs produced in 12 GeV p+A reactions are measured at the KEK-PS. We observed a significant enhancement over the known hadronic sources on the low-mass side of the ω meson peak. The 95 % C.L. allowed parameter regions for ρ/ω ratio are obtained as ρ/ω < 0.15 and ρ/ω < 0.31 for C and Cu targets, respectively. As for the φ meson, the data obtained with a Cu target revealed a significant excess on the low-mass side of the φ meson peak mainly in the βγφ < 1.25 region.

  2. Evidence of tensor interactions in 16O observed via (p,d) reaction

    International Nuclear Information System (INIS)

    We measured the differential cross sections of the 16O(p,d) reaction populating the ground state and several low-lying excited states in 15O using 198-, 295- and 392-MeV proton beams at the Research Center for Nuclear Physics (RCNP), Osaka University, to study the effect of the tensor interactions in 16O. Dividing the cross sections for each excited state by the one for the ground state and comparing the ratios over a wide range of momentum transfer, we found a marked enhancement of the ratio for the positive-parity state(s). The observation is consistent with large components of high-momentum neutrons in the ground-state configurations of 16O due possibly to the tensor interactions. (authors)

  3. In situ observation of the reaction of scandium and carbon by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Arellano, Erick A., E-mail: eajuarez@unpa.edu.m [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Winkler, Bjorn [Institut fuer Geowissenschaften, Universitaet Frankfurt, Altenhoeferallee 1, 60438 Frankfurt a.M. (Germany); Vogel, Sven C. [Los Alamos National Laboratory, Lujan Center. Mail Stop H805, Los Alamos, NM 87545 (United States); Senyshyn, Anatoliy [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, Lichtenbergstr. 1, D-85747 Garching (Germany); Materialwissenschaft, TU Darmstadt, Petersensstr. 23, D-64287 Darmstadt (Germany); Kammler, Daniel R. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Avalos-Borja, Miguel [CNyN, UNAM, A. Postal 2681, Ensenada, B.C. (Mexico)

    2011-01-05

    Research highlights: {yields} Exist two ScC cubic phases with B1-structure type differing in site occupancy of C. {yields} A new orthorhombic scandium carbide phase is formed at 1473(50) K. {yields} The recrystallization of alpha-Sc occurs between 1000 and 1223 K. - Abstract: The formation of scandium carbides by reaction of the elements has been investigated by in situ neutron diffraction up to 1823 K. On heating, the recrystallization of {alpha}-Sc occurs between 1000 and 1223 K. The formation of Sc{sub 2}C and ScC (NaCl-B1 type structure) phases has been detected at 1323 and 1373 K, respectively. The formation of a new orthorhombic scandium carbide phase was observed at 1473(50) K. Once the scandium carbides are formed they are stable upon heating or cooling. No other phases were detected in the present study, in which the system was always carbon saturated. The thermal expansion coefficients of all phases have been determined, they are constant throughout the temperature interval studied.

  4. Observation of the one- to six-neutron transfer reactions at sub-barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C.L.; Rehm, K.E.; Gehring, J. [and others

    1995-08-01

    It was suggested many years ago that when two heavy nuclei are in contact during a grazing collision, the transfer of several correlated neutron-pairs could occur. Despite considerable experimental effort, however, so far only cross sections for up to four-neutron transfers have been uniquely identified. The main difficulties in the study of multi-neutron transfer reactions are the small cross sections encountered at incident energies close to the barrier, and various experimental uncertainties which can complicate the analysis of these reactions. We have for the first time found evidence for multi-neutron transfer reactions covering the full sequence from one- to six-neutron transfer reactions at sub-barrier energies in the system {sup 58}Ni + {sup 100}Mo.

  5. Observation and Analysis of Affinity Law Deviations through Tested Performance of Liquefied Gas Reaction Turbines

    OpenAIRE

    Sarah D. Alison-Youel

    2008-01-01

    Liquefied gas reaction turbines are subject to the hydraulic affinity laws. Particularly for liquefied hydrocarbon gas-driven turbines, deviations from the affinity laws are encountered. In the case of reaction turbines, where the geometry is fixed, the affinity law relationships between flow, head, and rotational speed are relevant. Field experience confirms that the affinity law relationships are adequate, but that the predictions made also tend to deviate from real turbine performance. Par...

  6. In situ observation of surface species on iridium oxide nanoparticles during the oxygen evolution reaction

    OpenAIRE

    KAYA, Sarp; Casalongue, Hernan G. Sanchez; Ng, May Ling; Friebel, Daniel; Ogasawara, Hirohito; Nilsson, Anders

    2014-01-01

    An iridium oxide nanoparticle electrocatalyst under oxygen evolution reaction conditions was probed in situ by ambient-pressure X-ray photoelectron spectroscopy. Under OER conditions, iridium undergoes a change in oxidation state from Ir-IV to Ir-V that takes place predominantly at the surface of the catalyst. The chemical change in iridium is coupled to a decrease in surface hydroxide, providing experimental evidence which strongly suggests that the oxygen evolution reaction on iridium oxide...

  7. Rate Constant Change of Photo Reaction of Bacteriorhodopsin Observed in Trimeric Molecular System.

    Science.gov (United States)

    Tsujiuchi, Yutaka; Masumoto, Hiroshi; Goto, Takashi

    2016-04-01

    To elucidate the time evolution of photo reaction of bacteriorhodopsin in glycerol mixed purple membrane at around 196 K under irradiation by red light, a kinetic model was constructed. The change of absorption with irradiation at times of 560 nm and 412 nm was analyzed for the purpose of determining reaction rates of photo reaction of bacteriorhodopsin and its product M intermediate. In this study it is shown that reaction rates of conversion from bacteriorhodopsin to the M intermediate can be explained by a set of linear differential equations. This model analysis concludes that bacteriorhodopsin in which constitutes a trimer unit with other two bacteriorhodopsin molecules changes into M intermediates in the 1.73 of reaction rate, in the initial step, and according to the number of M intermediate in a trimer unit, from three to one, the reaction rate of bacteriorhodopsin into M intermediates smaller as 1.73, 0.80, 0.19 which caused by influence of inter-molecular interaction between bacteriorhodopsin. PMID:27451646

  8. Inelastic process observed in charge-exchange reactions of 56Fe at 500 MeV/u

    Directory of Open Access Journals (Sweden)

    Momota S.

    2014-03-01

    Full Text Available The inelastic (IE component of the reaction product, which is produced through charge-exchange reactions at relativistic energies of E ~ 1 GeV/u, is one of the hopeful probes used to study the nuclear medium effect on Δ excitation. In the present study, the longitudinal-momentum (PL distribution of 56Co, produced by bombarding C-and CH2-target with a primary beam of 56Fe at E=500 MeV/u, was observed by means of the spectrometer at HIMAC facility. The IE peak of 56Co, produced from H and C targets, was successfully observed in energy transfer spectrum. The behaviors of the IE peaks are consistent with those observed in previous experiments. A remarkable reduction of the energy transfer for the IE process was also observed with C target compared with H target. The present results have shown the feasibility to investigate the energy transfer in charge-exchange reactions for heavy reaction system at the energy down to 500 MeV/u.

  9. The reaction 13C(alpha,n)16O: a background for the observation of geo-neutrinos

    OpenAIRE

    Harissopulos, S.; Becker, H. W.; Hammer, J. W.; Lagoyannis, A.; Rolfs, C.; Strieder, F

    2005-01-01

    The absolute cross section of the $^{13}$C($\\alpha$,n)$^{16}$O reaction has been measured at E$_{\\alpha}$ = 0.8 to 8.0 MeV with an overall accuracy of 4%. The precision is needed to subtract reliably a background in the observation of geo-neutrinos, e.g. in the KamLAND detector.

  10. Low-energy resonances in the 22Ne(p,γ23Na reaction directly observed at LUNA

    Directory of Open Access Journals (Sweden)

    Cavanna Francesca

    2015-01-01

    A study of this reaction has been carried out at the Laboratory for Underground Nuclear Astrophysics (LUNA, in the Gran Sasso National Laboratory, using a windowless gas target and two high-purity germanium detectors. Several resonances have been observed for the first time in a direct experiment.

  11. Polarization observables in the $e^+ e^- \\rightarrow \\bar{\\Lambda} \\Lambda$ reaction

    CERN Document Server

    Fäldt, Göran

    2016-01-01

    Cross-section, vector-polarization, and tensor-polarization distributions are calculated for the reactions $e^+ e^- \\rightarrow \\bar{p}p$ and $e^+ e^- \\rightarrow \\bar{\\Lambda} \\Lambda$. Each reaction requires six characteristic functions that are bilinear in the, possibly complex, electromagnetic form factors, denoted $G_E(P^2)$ and $G_M(P^2)$, of $p$ and $\\Lambda$. For the hyperon reaction also the joint-decay distributions of $\\Lambda$ and $\\bar{\\Lambda}$ are calculated. Their knowledge allow a complete determination of the hyperon electromagnetic form factors, without measuring hyperon spins. We explain how this is done in practice. For some tensor-polarization components our results are in conflict with previously repeatedly published distributions.

  12. Polymerization dependence of the reactivity of polyacrylamide observed with hydrogen-isotope exchange reaction in a liquid-solid system

    International Nuclear Information System (INIS)

    The tritium (T) labeled polyacrylamide (abbreviated PAAm(T) below) was synthesized using the hydrogen-isotope exchange reaction (gas-solid reaction) between HTO vapor and PAAm. The degree of the polymerization of PAAm used was 2800 (and 80000) (abbreviated PAAm2800 (and PAAm80000) below). Using the PAAm(T) thus obtained, the hydrogen-isotope exchange reaction (liquid-solid reaction) between PAAm(T) and each liquid organic material has been observed at the temperature range of 50 to 90degC. Applying the A''-McKay plot method to the data thus obtained, the rate constant (k) for the reaction was obtained. Including k obtained previously, the value of k thus obtained were compared with each other. The following six items have consequently been confirmed. The reactivity of PAAm80000 is larger than that of PAAm2800. PAAm2800 is about 0.4 times PVA2900 in reactivity. The temperature dependence of the reactivity of PAAm2800 is about 6 times that of PVA-2900. The reactivity of these three compounds for several liquid organic materials can roughly be expressed as follows: (PVA2900):(PAAm80000):(PAAm2800)=1:1:0.3. It is possible to use PAAm as a solid material in the liquid-solid reaction (instead of PVA). The method used in this work can be useful to clarify the reactivity of a certain material, and to obtain the data for the prevention of tritium-contamination. (author)

  13. Fenton reaction induced cancer in wild type rats recapitulates genomic alterations observed in human cancer.

    Directory of Open Access Journals (Sweden)

    Shinya Akatsuka

    Full Text Available Iron overload has been associated with carcinogenesis in humans. Intraperitoneal administration of ferric nitrilotriacetate initiates a Fenton reaction in renal proximal tubules of rodents that ultimately leads to a high incidence of renal cell carcinoma (RCC after repeated treatments. We performed high-resolution microarray comparative genomic hybridization to identify characteristics in the genomic profiles of this oxidative stress-induced rat RCCs. The results revealed extensive large-scale genomic alterations with a preference for deletions. Deletions and amplifications were numerous and sometimes fragmented, demonstrating that a Fenton reaction is a cause of such genomic alterations in vivo. Frequency plotting indicated that two of the most commonly altered loci corresponded to a Cdkn2a/2b deletion and a Met amplification. Tumor sizes were proportionally associated with Met expression and/or amplification, and clustering analysis confirmed our results. Furthermore, we developed a procedure to compare whole genomic patterns of the copy number alterations among different species based on chromosomal syntenic relationship. Patterns of the rat RCCs showed the strongest similarity to the human RCCs among five types of human cancers, followed by human malignant mesothelioma, an iron overload-associated cancer. Therefore, an iron-dependent Fenton chemical reaction causes large-scale genomic alterations during carcinogenesis, which may result in distinct genomic profiles. Based on the characteristics of extensive genome alterations in human cancer, our results suggest that this chemical reaction may play a major role during human carcinogenesis.

  14. Consistency between the monopole strength of the Hoyle state determined by structural calculation and that extracted from reaction observables

    CERN Document Server

    Minomo, Kosho

    2016-01-01

    We analyze the $\\alpha$-$^{12}$C inelastic scattering to the $0^+_2$ state of $^{12}$C, the Hoyle state, in a fully microscopic framework. With no free adjustable parameter, the inelastic cross sections at forward angles are well reproduced by the microscopic reaction calculation using the transition density of $^{12}$C obtained by the resonating group method and the nucleon-nucleon $g$ matrix interaction developed by the Melbourne group. It is thus shown that the monopole transition strength obtained by the structural calculation is consistent with that extracted from the reaction observable, suggesting no missing monopole strength of the Hoyle state.

  15. Observation of hydroxymethyl hydroperoxide in a reaction system containing CH2OO and water vapor through pure rotational spectroscopy

    International Nuclear Information System (INIS)

    Pure rotational transitions of hydroxymethyl hydroperoxide (HMHP) were observed in the discharged plasma of a CH2I2/O2/water gas mixture, where the water complex with the simplest Criegee intermediate CH2OO has been identified [M. Nakajima and Y. Endo, J. Chem. Phys. 140, 134302 (2014)]. Isotope experiments using heavy water support that the currently observed HMHP molecule was produced by the reaction of CH2OO with water vapor. The observed species was identified as the most stable conformer with the help of quantum chemical calculations. We also clarified that productions of formic acid and dioxirane are promoted by the existence of water vapor in the discharged reaction system

  16. Observation of Λ-hypernuclei in the reaction 12C(π+,K+)/sub Λ/12C

    International Nuclear Information System (INIS)

    The observation of Λ-hypernuclear levels in /sub Λ/12C by associated production through the (π+,K+) reaction is reported. Spectrometers used in the measurements are discussed. The /sub Λ/12C excitation energy spectra were recorded at laboratory scattering angles of 5.60, 10.30, and 15.20. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup π/ = 2+ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (π+,K+) reaction, compared to the (K-,π-) reaction in which lower spin states are excited. 29 refs., 40 figs

  17. Ionic Debye Screening in Dense Liquid Plasmas Observed for Li+p,d Reactions with Liquid Li Target

    Institute of Scientific and Technical Information of China (English)

    J.Kasagi; H.Yonemura; Y.Toriyabe; A.Nakagawa; T.Sugawara; WANG Tie-shan

    2009-01-01

    Thick target yields of a particles emitted in the ~6Li(d,a)~4 He and ~7Li(p,a)~4 He reactions were measured for Li target in the solid and liquid phase.Observed reaction rates for the liquid Li are always larger than those for the solid.This suggests that the stopping power of hydrogen ion in the liquid Li metal might be smaller than in the solid.Using the empirically obtained stopping power for the liquid Li,we have deduced the screening potentials of the Li+p and Li+d reactions in both phases.The deduced screening potential for the liquid Li is about 500 eV larger than for the solid.This difference is attributed to the effect of liquefied Li~+ ions.It is concluded that the ionic screening is much stronger than the electronic screening in a low-temperature dense plasmas.

  18. Observation of Spontaneous C=C Bond Breaking in the Reaction between Atomic Boron and Ethylene in Solid Neon.

    Science.gov (United States)

    Jian, Jiwen; Lin, Hailu; Luo, Mingbiao; Chen, Mohua; Zhou, Mingfei

    2016-07-11

    A ground-state boron atom inserts into the C=C bond of ethylene to spontaneously form the allene-like compound H2 CBCH2 on annealing in solid neon. This compound can further isomerize to the propyne-like HCBCH3 isomer under UV light excitation. The observation of this unique spontaneous C=C bond insertion reaction is consistent with theoretical predictions that the reaction is thermodynamically exothermic and kinetically facile. This work demonstrates that the stronger C=C bond, rather than the less inert C-H bond, can be broken to form organoboron species from the reaction of a boron atom with ethylene even at cryogenic temperatures. PMID:27240114

  19. Observation of. lambda. -hypernuclei in the reaction /sup 12/C(. pi. /sup +/,K/sup +/)/sub. lambda. //sup 12/C

    Energy Technology Data Exchange (ETDEWEB)

    Milner, E.C.

    1985-12-01

    The observation of ..lambda..-hypernuclear levels in /sub ..lambda..//sup 12/C by associated production through the (..pi../sup +/,K/sup +/) reaction is reported. Spectrometers used in the measurements are discussed. The /sub ..lambda..//sup 12/C excitation energy spectra were recorded at laboratory scattering angles of 5.6/sup 0/, 10.3/sup 0/, and 15.2/sup 0/. The spectra show two major peaks - one attributed to the ground state, and one about 11 MeV higher in excitation. The peak near 11 MeV excitation energy is believed to be almost entirely composed of a multiplet of three J/sup ..pi../ = 2/sup +/ states. Relativistic DWBA calculations imply support for the expectation that higher spin states are preferentially populated in the (..pi../sup +/,K/sup +/) reaction, compared to the (K/sup -/,..pi../sup -/) reaction in which lower spin states are excited. 29 refs., 40 figs.

  20. Chemotherapy-induced adverse drug reactions in oncology patients: A prospective observational survey

    OpenAIRE

    Deepti Chopra; Rehan, Harmeet S.; Vibha Sharma; Ritu Mishra

    2016-01-01

    Background: Chemotherapy, a multimodal approach to oncological treatment, involves highly complex regimens and hence accounts to high susceptibility toward adverse drug reactions (ADRs). The present study aims to determine the prevalence of adverse events in patients treated with chemotherapy. Materials and Methods: Spontaneous ADR report of patients on antineoplastic drugs received in the past 2 years (January 2011-January 2013) were studied. These reports were analyzed for various carcinoma...

  1. An Allergic Reaction (Anaphylaxis) Observed Before Open Heart Surgery in the Operating Room

    OpenAIRE

    Altın, Fırat; Aydın, Selim; Eygi, Börteçin; Güneş, Tevfik; Erkoç, Kamuran; Kutas, Barış

    2012-01-01

    Anaphylaxis and anaphylactoid reactions under general anesthesia are serious events and are often regarded as life threatening situations. A 57-year-old woman was admitted to cardiothora-cic surgery clinic for coronary artery by-pass grafting procedure with a diagnosis of coronary artery disease following a diagnostic coronary artery angiography. Upon arrival to the operating room, after necessary monitoring, general anesthesia was administered. Sterile placement of a central venous catheter ...

  2. Dynamical evolution of angular momentum in damped nuclear reactions. II. Observation of angular momentum through sequential decay

    International Nuclear Information System (INIS)

    The angular momentum built up in the fragment nuclei during a damped nuclear reaction is subsequently lost through decay. Since the decay is very fast, the only way to learn about the angular momentum accumulated in the nuclei is to observe the sequential decay products. The present investigation aims at providing precise methods for calculating properties of the sequential decay on the basis of primary spin distributions calculated with the transfer theory

  3. Observation and Analysis of Affinity Law Deviations through Tested Performance of Liquefied Gas Reaction Turbines

    Directory of Open Access Journals (Sweden)

    Sarah D. Alison-Youel

    2008-11-01

    Full Text Available Liquefied gas reaction turbines are subject to the hydraulic affinity laws. Particularly for liquefied hydrocarbon gas-driven turbines, deviations from the affinity laws are encountered. In the case of reaction turbines, where the geometry is fixed, the affinity law relationships between flow, head, and rotational speed are relevant. Field experience confirms that the affinity law relationships are adequate, but that the predictions made also tend to deviate from real turbine performance. Part of the deviations seen may be attributed to the nonideal fluid; however, further examination is warranted. This paper presents an investigation into the affinity law relationships between head, flow, and rotational speed in conjunction with actual turbine performance. The three basic affinity law relationships are combined to form the most general performance equation. This equation subsequently incorporates both the affinity law relationships and the conservation of energy principal. Application of real turbine test data shows that this general performance equation presents a more accurate representation of turbine performance than the affinity law relationships alone.

  4. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaka, Masanari, E-mail: nagasaka@ims.ac.jp; Kosugi, Nobuhiro [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585 (Japan); Yuzawa, Hayato; Horigome, Toshio [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan)

    2014-10-15

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates.

  5. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    Science.gov (United States)

    Nagasaka, Masanari; Yuzawa, Hayato; Horigome, Toshio; Kosugi, Nobuhiro

    2014-10-01

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates.

  6. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method

    International Nuclear Information System (INIS)

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates

  7. In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method.

    Science.gov (United States)

    Nagasaka, Masanari; Yuzawa, Hayato; Horigome, Toshio; Kosugi, Nobuhiro

    2014-10-01

    In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates. PMID:25362423

  8. Few-body nuclear reactions at low energies – an investigation on observed anomalies

    International Nuclear Information System (INIS)

    Few-body aspects of nuclear interaction are expected to be best studied at sufficiently lower energies where various pair-wise interactions overlap effectively with one another in the allowed phase space in kinematically complete configuration. In this direction, next to nucleon-deuteron systems, a very powerful testing ground has been the alpha-deuteron system where the alpha particle could be treated as a structureless boson due to its very high binding energy. The aim of the present work is to examine the strong anomalies observed in explaining the kinematically complete experimental observables in the light of Faddeev theoretical calculations (FT) due to Koike, involving alpha-induced break-up of deuterons at comparatively lower energies, ranging from Eα(inc)=11 to 18 MeV

  9. Observation of the reaction γγ->panti pπ+π-

    International Nuclear Information System (INIS)

    Production of the panti pπ+π- final state by two-photon scattering was observed. The cross section for γγ -> panti pπ+π- was determined assuming phase space production. No evidence was found for the production or formation of resonances. Upper limits are given for Λ and Δ pair production, for production of panti prho0 and for the two-photon excitation of canti c bound states. (orig.)

  10. Observation of the reaction γγ->panti pπ+π-

    International Nuclear Information System (INIS)

    Production of the panti pπ+π- final state by two photon scattering was observed. The cross section for γγ->panti pπ+π- was determined assuming phase space production. No evidence was found for the production or formation of resonances. Upper limits are given for Λ and Δ pair production, for production of panti prho0 and for the two photon excitation of canti c bound states. (orig.)

  11. Chemotherapy-induced adverse drug reactions in oncology patients: A prospective observational survey

    Directory of Open Access Journals (Sweden)

    Deepti Chopra

    2016-01-01

    Full Text Available Background: Chemotherapy, a multimodal approach to oncological treatment, involves highly complex regimens and hence accounts to high susceptibility toward adverse drug reactions (ADRs. The present study aims to determine the prevalence of adverse events in patients treated with chemotherapy. Materials and Methods: Spontaneous ADR report of patients on antineoplastic drugs received in the past 2 years (January 2011-January 2013 were studied. These reports were analyzed for various carcinomas under treatment, medications used, types of ADRs, organ system involvement, severity, causality assessment, and preventability. Results: Over a period of 2 years, a total 591 cases were received with an incidence of 58.6%. The prevalence of ADRs was more in female patients (73.6% as compared to men. ADRs mostly occurred in the age group of 41-50 years (27.4%. Patients treated for breast carcinoma (39.1% reported the highest incidence of ADRs. Cisplatin (19.6% was found to be the most common offending drug. The most common ADR reported was nausea and vomiting (23%. Gastroenterology (40.1% was the most affected system. About 50.2% of the ADRs required treatment and 12.9% ADRs were considered serious. Causality assessment revealed that 80% of the ADRs were possible. About 86.97% cases were found to be mild, and 51% were not preventable. Conclusion: The success of chemotherapy comes with the word of caution regarding toxicities of antineoplastic drugs. Pharmacovigilance of these drugs needs to be explored, and use of preventative measures needs to be enhanced in order to reduce the incidence and severity of ADRs.

  12. Removing flow backgrounds from the charge-separation observable perpendicular to the reaction plane in heavy-ion collisions

    CERN Document Server

    Wen, Fufang; Wang, Gang

    2016-01-01

    Recent charge-dependent azimuthal correlation measurements in high-energy heavy-ion collisions have observed charge-separation signals perpendicular to the reaction plane, and the observations have been related to the chiral magnetic effect (CME). However, the correlation signal is contaminated with the background contributions due to the collective motion (flow) of the collision system, and it remains elusive to effectively remove the background from the correlation. We present a method study with Monte Carlo simulations and a multi-phase transport model, and develop a scheme to reveal the true CME signal via the event-shape engineering with the flow vector, $\\overrightarrow{q}$. An alternative approach using the ensemble averages of observables is also discussed.

  13. Observation of low-lying resonances in the quasicontinuum of 195,196Pt and enhanced astrophysical reaction rates

    International Nuclear Information System (INIS)

    An excess of strength on the low-energy tail of the giant dipole resonance recently has been observed in the γ-decay from the quasicontinuum of 195,196Pt. The nature of this phenomenon is not yet fully investigated. If this feature is present also in the γ-ray strength of the neutron-rich isotopes, it can affect the neutron-capture reactions involved in the formation of heavy-elements in stellar nucleosynthesis. The experimental level density and γ-ray strength function of 195,196Pt are presented together with preliminary calculations of the corresponding neutron-capture cross sections

  14. Three Axis Control of the Hubble Space Telescope Using Two Reaction Wheels and Magnetic Torquer Bars for Science Observations

    Science.gov (United States)

    Hur-Diaz, Sun; Wirzburger, John; Smith, Dan

    2008-01-01

    The Hubble Space Telescope (HST) is renowned for its superb pointing accuracy of less than 10 milli-arcseconds absolute pointing error. To accomplish this, the HST relies on its complement of four reaction wheel assemblies (RWAs) for attitude control and four magnetic torquer bars (MTBs) for momentum management. As with most satellites with reaction wheel control, the fourth RWA provides for fault tolerance to maintain three-axis pointing capability should a failure occur and a wheel is lost from operations. If an additional failure is encountered, the ability to maintain three-axis pointing is jeopardized. In order to prepare for this potential situation, HST Pointing Control Subsystem (PCS) Team developed a Two Reaction Wheel Science (TRS) control mode. This mode utilizes two RWAs and four magnetic torquer bars to achieve three-axis stabilization and pointing accuracy necessary for a continued science observing program. This paper presents the design of the TRS mode and operational considerations necessary to protect the spacecraft while allowing for a substantial science program.

  15. Construction of the undulator beamline equipped with a UHV-STM for observations of synchrotron-radiation-stimulated surface reaction

    International Nuclear Information System (INIS)

    An undulator beamline equipped with a UHV-scanning tunneling electron microscopy (STM) system has been designed and constructed at the UVSOR facility to investigate synchrotron-radiation-stimulated reactions. Using this undulator beamline, we have observed irradiation effects on the hydrogen terminated-(H-) Si(1 1 1) surfaces in atomic scale. The small protrusions, which are assigned to the rest-atom with missing H, appeared on the monohydride surface after irradiation. The density of them monotonically increased with irradiation dose. This phenomenon has been observed almost independent on the Si 2p core electron excitation threshold, indicating the significant contribution of the valence electron excitations to the Si-H bond dissociations

  16. Does slow energy transfer limit the observed time constant for radical pair formation in photosystem II reaction centers?

    Science.gov (United States)

    Rech, T; Durrant, J R; Joseph, D M; Barber, J; Porter, G; Klug, D R

    1994-12-13

    We have used spectrally photoselective femtosecond transient absorption spectroscopy on photosystem II reaction centers to show that there are at least two pools of chlorin molecules/states which can transfer excitation energy to P680, the primary electron donor in photosystem II. It has previously been shown that one chlorin pool equilibrates with P680 in 100 fs [Durrant et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 11632-11636], and we report here the observation of energy transfer from a second more weakly coupled chlorin pool. The effect of the weakly coupled pool is to increase the apparent time constant for radical pair formation from 21 ps when P680 is selectively excited to 27 ps when the accessory chlorins are excited. We conclude that it is possible to observe both radical pair formation somewhat slowed by an energy transfer step and radical pair formation not limited by this slow energy transfer, depending upon which chromophores are initially excited. These observations provide evidence that when using photoselective excitation of P680, the observed 21 ps time constant for radical pair formation is not limited by a slow energy transfer step. PMID:7993905

  17. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  18. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    Directory of Open Access Journals (Sweden)

    F. Flocke

    2009-11-01

    the submicrometer aerosol has a much larger effect on aerosol optical properties than changes to the hygroscopic:hydrophobic mass fractions of the accumulation mode aerosol.

    In the presence of dust, nitric acid concentrations are reduced to <50% of total nitrate (nitric acid plus particulate nitrate. NOy as a fraction of total nitrogen (NOy plus particulate nitrate, is reduced from >85% to 60–80% in the presence of dust. These observations support previous model studies which predict irreversible sequestration of reactive nitrogen species through heterogeneous reactions with mineral dust during long-range transport.

  19. Observation of stable HO4(+) and DO4(+) ions from ion-molecule reactions in helium nanodroplets.

    Science.gov (United States)

    Renzler, Michael; Ralser, Stefan; Kranabetter, Lorenz; Barwa, Erik; Scheier, Paul; Ellis, Andrew M

    2016-05-21

    Ion-molecule reactions between clusters of H2/D2 and O2 in liquid helium nanodroplets were initiated by electron-induced ionization (at 70 eV). Reaction products were detected by mass spectrometry and can be explained by a primary reaction channel involving proton transfer from H3(+) or H3(+)(H2)n clusters and their deuterated equivalents. Very little HO2(+) is seen from the reaction of H3(+) with O2, which is attributed to an efficient secondary reaction between HO2(+) and H2. On the other hand HO4(+) is the most abundant product from the reaction of H3(+) with oxygen dimer, (O2)2. The experimental data suggest that HO4(+) is a particularly stable ion and this is consistent with recent theoretical studies of this ion. PMID:27140863

  20. Linear free energy relationship and deuterium kinetic isotope effect observed on phospho and thiophosphoryl transfer reactions in some organophosphorous compounds

    International Nuclear Information System (INIS)

    Tetracoordinated organophosphorous compounds were synthesized, characterized and nucleophilic substitution reaction were investigated by varying substituents around phosphorous centre or in nucleophile considering its utility in biological and environmental system. The reactivity is expressed in terms of second-order rate constant, k2 and measured conductometrically. Linear Free Energy Relationship (LFER) tools mainly Hammett (ρ), Brönsted (β) LFER coefficients and deuterium kinetic isotope effects (KIEs) being determined for the pyridinolysis of 4 – chlorophenyl 4 – methoxy phenyl chlorophosphate, 1 in acetonitrile at 5.0 °C. The experimental data's were compared with those of structurally similar organophosphorous compounds reported earlier in quest for the mechanistic information. Nice linear correlation being found for Hammett (logk2 vs σx), having negative value of the ρX = −5.85 and Brönsted (logk2 vs pKa(x)) plots having large positive value for βX = 1.18 for 1 can be interpreted as SN2 process with greater extent of bond formation in transition state (TS) of 1. The observed kH/kD values of 1 is 1.00 ± 0.05 and net KIE, 1.32 suggests the primary KIE and indicates frontside nucleophilic attack through the partial deprotonation of pyridine occurs by the hydrogen bonding in the rate-determining step.

  1. Observation of a chemically labile, noncovalent enzyme intermediate in the reaction of metal-dependent Aquifex pyrophilus KDO8PS by time-resolved mass spectrometry

    OpenAIRE

    Roberts, Anne; Furdui, Cristina; Anderson, Karen S.

    2010-01-01

    The direct detection of intermediates in enzymatic reactions can yield important mechanistic insights but may be difficult due to short intermediate lifetimes and chemical instability. Using a rapid-mixing device coupled with electrospray ionization time-of-flight mass spectrometry, the noncova-lent hemiketal intermediate in the reaction of metal-dependent 3-deoxy-D-manno-octulosonate-8-phosphate (KDO8P) synthase from Aquifex pyrophilus was observed in the millisecond time range. Using single...

  2. Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

    International Nuclear Information System (INIS)

    In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO2. The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

  3. Velocity-space observation regions of high-resolution two-step reaction gamma-ray spectroscopy

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nocente, M.; Gorini, G.;

    2015-01-01

    example. The energy-dependent cross sections of this reaction suggest that GRS is sensitive to alpha particles above about 1.7 MeV and highly sensitive to alpha particles at the resonance energies of the reaction. Here we demonstrate that highresolution two-step reaction GRS measurements are not only...... selective in energy but also in pitch angle. They can be highly sensitive in particular pitch angle ranges and completely insensitive in others. Moreover, GRS weight functions allow rapid calculation of γ-ray energy spectra from fast-ion distribution functions, additionally revealing how many photons any...

  4. Observation and analysis of incomplete fusion reactions induced by (12C, 14N, 16O, 22Ne) ions

    International Nuclear Information System (INIS)

    The mechanism of the reactions induced by heavy ions has been studied. The experiments were concerned with incident channels which lead to the formation of intermediate nuclei with atomic mass (6412C, 14N, 16O, 22Ne) as projectiles respectively. The detection of light fragments (2< Z<12) is studied. A three solid-state-detector telescope, with associated electronics is used which allows the separation of reaction products according to their charge. The main features of deep inelastic collisions are discussed: large kinetic energy loss, and important nucleon transfer as a function of the angular detection. The time evolution of the reaction has been studied, then the results are compared with a scattering model suggested by Noremberg. A theoretical calculation based on both classical and statistical approaches giving the total cross-sections for any exit channel has been proposed

  5. First observation of new heavy multi-nucleon transfer products in the 48Ca+248Cm reaction performed at SHIP

    International Nuclear Information System (INIS)

    Heavy ion fusion reactions have been successfully used to synthesise super heavy elements (SHE). The heaviest element produced up to now is element Z=118 and the production cross-section limit using conventional HI-fusion has been reached experimentally. Since these methods cannot be applied to reach neutron-rich super heavy nuclei due to the lack of sufficiently neutron-rich projectile and target nuclei. New calculations suggest the use of Multi Nucleon Transfer (MNT) reactions as a promising pathway to the synthesis of new neutron-rich SHE with proton numbers up to about Z=106. In this work, we present results from the analysis of experimental data on MNT reactions with the 48Ca projectile incident on 248Cm target. The experiment was performed at SHIP, GSI in 2010

  6. Low dose endotoxin priming is accountable for coagulation abnormalities and organ damage observed in the Shwartzman reaction. A comparison between a single-dose endotoxemia model and a double-hit endotoxin-induced Shwartzman reaction

    Directory of Open Access Journals (Sweden)

    Cate Hugo

    2006-08-01

    Full Text Available Abstract The clinical response of sepsis to a systemic inflammatory infection may be complicated by disseminated intravascular coagulation or DIC. In order to experimentally study the syndrome of DIC, we aimed for a severe sepsis model complicated by disseminated coagulation. Most -simplified- experimental models describing coagulation abnormalities as a consequence of sepsis are based on single dose endotoxemia. The so called-Shwartzman reaction contrarily, is elicited by a low dose endotoxin priming followed by an LPS challenge and is characterized by pathological manifestations that represent the syndrome of DIC. In order to investigate whether the Shwartzman reaction is superior to a single endotoxin challenge as a model for sepsis-induced DIC and to determine what the pathological effect is of an encounter of low endotoxin prior to an LPS challenge, we undertook the present study. In this study we demonstrate that low-dose endotoxin priming prior to an LPS challenge in the Shwartzman reaction is accountable for micro-vascular thrombosis in lung and liver and subsequent (multi- organ failure, not observed after a single-dose endotoxin challenge, which indicates that the Shwartzman reaction is well suited-model to study sepsis-induced DIC adversities. Remarkably, only minor differences in the innate immune response were established between the single-dose endotoxin challenge and the Shwartzman reaction.

  7. Measurement of spin observables in the quasi-free np-> {pp}_s pi- reaction at 353 MeV

    CERN Document Server

    Dymov, S; Azaryan, T; Barsov, S; Baru, V; Benati, P; Chiladze, D; Dzyuba, A; Engels, R; Gaisser, M; Gebel, R; Grigoryev, K; Goslawski, P; Guidoboni, G; Hartmann, M; Kacharava, A; Kamerdzhiev, V; Khoukaz, A; Komarov, V; Kulessa, P; Kulikov, A; Kurbatov, V; Lehrach, A; Lenisa, P; Lensky, V; Lomidze, N; Lorentz, B; Macharashvili, G; Maier, R; Mchedlishvili, D; Merzliakov, S; Mielke, M; Mikirtychyants, M; Mikirtytchiants, S; Nioradze, M; Oellers, D; Ohm, H; Polyanskiy, A; Papenbrock, M; Prasuhn, D; Rathmann, F; Serdyuk, V; Seyfarth, H; Steffens, E; Stein, H J; Stockhorst, H; Ströher, H; Tabidze, M; Trusov, S; Tsirkov, D; Uzikov, Yu; Valdau, Yu; Weidemann, Ch; Wilkin, C; Wüstner, P; Ye, Q J; Zhabitsky, M

    2013-01-01

    The transverse spin correlations A_{x,x} and A_{y,y} have been measured in the pol{d} pol{p} -> p_spec {pp}_s pi- reaction at COSY-ANKE at 353 MeV per nucleon. Here {pp}_s denotes a proton-proton pair with low excitation energy, which is dominantly in the 1S0 state. By measuring three protons in the final state it was possible to extract events where there was a spectator proton p_spec so that the reaction could be interpreted in terms of quasi-free pol{n} pol{p} -> {pp}_s pi-. The proton analyzing power in this reaction was also deduced from this data set by averaging over the polarization of the deuteron beam. The values of A_y^p were shown to be consistent with a refined analysis of our earlier results obtained with a polarized proton incident on a deuterium target. Taking these data in combination with our earlier measurements of the differential cross sections and analyzing powers in the pol{p} p -> {pp}_s pi^0 reaction, a more robust partial wave decomposition was achieved. Three different acceptable so...

  8. Observation of hydroxymethyl hydroperoxide in a reaction system containing CH{sub 2}OO and water vapor through pure rotational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Masakazu; Endo, Yasuki, E-mail: endo@bunshi.c.u-tokyo.ac.jp [Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2015-10-28

    Pure rotational transitions of hydroxymethyl hydroperoxide (HMHP) were observed in the discharged plasma of a CH{sub 2}I{sub 2}/O{sub 2}/water gas mixture, where the water complex with the simplest Criegee intermediate CH{sub 2}OO has been identified [M. Nakajima and Y. Endo, J. Chem. Phys. 140, 134302 (2014)]. Isotope experiments using heavy water support that the currently observed HMHP molecule was produced by the reaction of CH{sub 2}OO with water vapor. The observed species was identified as the most stable conformer with the help of quantum chemical calculations. We also clarified that productions of formic acid and dioxirane are promoted by the existence of water vapor in the discharged reaction system.

  9. Direct estimation of the rate constant of the reaction ClO + HO2 → HOCl + O2 from SMILES atmospheric observations

    Directory of Open Access Journals (Sweden)

    K. Kuribayashi

    2013-05-01

    Full Text Available Diurnal variations of ClO, HO2, and HOCl were simultaneously observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES between 12 October 2009 and 21 April 2010. These were the first global observations of the diurnal variation of HOCl in the upper atmosphere. A major reaction to produce HOCl is ClO + HO2 → HOCl + O2 (R1 in extra polar region. A model study suggested that in the mesosphere during night this is the only reaction influencing the amount of HOCl and ClO. The evaluation of the pure reaction period, where only reaction (R1 occurred in Cly chemical system, was performed by the consistency between two reaction rates, HOCl production and ClO loss, from SMILES observation data. It turned out that the SMILES data at the pressure level of 0.28 hPa (about 58 km during night (between local time 18:30 and 04:00 in the autumn mid-latitude region (20–40° February–April 2010 were suitable for the estimation of k1. The rate constant was obtained to be k1(245 K = 7.73 ± 0.26 (1σ [× 10–12 cm3/molecule s] from SMILES atmospheric observations. This result was consistent with that from both the laboratory experiment and the ab initio calculations for similar low-pressure conditions. The 1σ precision of k1 obtained was 2–10 times better than those of previous laboratory measurements.

  10. Observation of spin-parity 2+ dominance in the reaction γγ→ρ0ρ0 near threshold

    International Nuclear Information System (INIS)

    The reaction γγ→π+π-π+π- has been studied with the ARGUS detector. The rate in the invariant mass region below 1.8 GeV/c2 is found to be largely due to ρ0ρ0 production. A spin-parity analysis shows a dominance of the partial wave (JP, Jz)=(2+, 2) with a small admixture from JP=0+. The contribution of negative parity states is consistent with zero. The large ratio of cross sections σ(γγ→ρ0ρ0)/σ(γγ→ρ+ρ-)≅4, and the dominance of the JP=2+ wave in the reaction γγ→ρ0ρ0 is a signature consistent with the production of an exotic (I=2) resonance. (orig.)

  11. Observation of the n(3He,t)p Reaction by Detection of Far-Ultraviolet Radiation

    CERN Document Server

    Thompson, Alan K; Cooper, John W; Hughes, Patrick; Vest, Robert E; Clark, Charles W

    2008-01-01

    We have detected Lyman alpha radiation as a product of the n(3He,t)p nuclear reaction occurring in a cell of 3He gas. The predominant source of this radiation appears to be decay of the 2p state of tritium produced by charge transfer and excitation collisions with the background 3He gas. Under the experimental conditions reported here we find yields of tens of Lyman alpha photons for every neutron reaction. These results suggest a method of cold neutron detection that is complementary to existing technologies that use proportional counters. In particular, this approach may provide single neutron sensitivity with wide dynamic range capability, and a class of neutron detectors that are compact and operate at relatively low voltages.

  12. Measurement of the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction cross section, of relevance to $\\gamma$-ray observation of core collapse supernovae, using reclaimed $^{44}$Ti

    CERN Multimedia

    Despite decades of research, fundamental uncertainties remain in the underlying explosion mechanism of core collapse supernovae. One of the most direct methods that might help resolve this problem is a comparison of the predicted to the observed flux of $\\gamma$-rays due to decay of $^{44}$Ti produced in the explosion, as it is believed this could reveal the location of the mass cut, a key hydrodynamical property of the explosion. Such a study is at present limited by the uncertainty in the $^{44}$Ti($\\alpha$,p)$^{47}$V reaction rate. In this experiment we propose to measure the cross section for this reaction at astrophysically relevant energies. The single previous measurement of this reaction was limited to higher energies due to low beam intensities. Here, a more intense beam will be employed, generated from $^{44}$Ti reclaimed as part of the ERAWAST project at PSI.

  13. Charge transfer coefficients for the O+/2D/ + N2 and O+/2D/ + O2 excited ion reactions at thermal energy. [from ionospheric observations

    Science.gov (United States)

    Johnsen, R.; Biondi, M. A.

    1980-01-01

    An investigation of the reactions of metastable O(+) ions and O2 using drift tube-mass spectrometer techniques is presented. It was shown that ordinary charge transfer is the dominant reaction branch in both cases; it occurs with large rate coefficients, k(N2) = (8 + or - 2) x 10 to the -10th cu cm/s and k(O2) = (7 + or - 2) x 10 to the -10th cu cm/s, at an effective ion temperature of about 550 K. The reaction He(+) + O2 is used as a source of metastable O(+) ions, and evidence is presented that the O(+) ions so produced are in the 2D state rather than the 2P state. The results are compared with previous measurements, and inferences drawn from ionospheric observations.

  14. Observations of heterogeneous reactions between Asian pollution and mineral dust over the Eastern North Pacific during INTEX-B

    OpenAIRE

    C. S. McNaughton; A. D. Clarke; V. Kapustin; Shinozuka, Y.; S. G. Howell; Anderson, B. E.; E. Winstead; Dibb, J.; E. Scheuer; Cohen, R. C.; Wooldridge, P.; Perring, A.; L. G. Huey; Kim, S.; Jimenez, J. L.

    2009-01-01

    In-situ airborne measurements of trace gases, aerosol size distributions, chemistry and optical properties were conducted over Mexico and the Eastern North Pacific during MILAGRO and INTEX-B. Heterogeneous reactions between secondary aerosol precursor gases and mineral dust lead to sequestration of sulfur, nitrogen and chlorine in the supermicrometer particulate size range.

    Simultaneous measurements of aerosol size distributions and weak-acid soluble calcium result in an ...

  15. Observation of Organometallic and Radical Intermediates Formed during the Reaction of Methyl-Coenzyme M Reductase with Bromoethanesulfonate†

    OpenAIRE

    Li, Xianghui; Telser, Joshua; Hoffman, Brian M.; Gerfen, Gary; Ragsdale, Stephen W.

    2010-01-01

    Methyl-coenzyme M reductase (MCR) from methanogenic archaea catalyzes the final step of methane formation, in which methyl-coenzyme M (2-methylthioethane sulfonate, methyl-SCoM) is reduced with coenzyme B (N-7-mercaptoheptanolyl-threonine phosphate, CoBSH) to form methane and the heterodisulfide CoBS-SCoM. The active dimeric form of MCR contains two Ni(I)-F430 prosthetic groups, one in each monomer. This manuscript describes studies of the reaction of the active Ni(I) state of MCR (MCRred1) w...

  16. Observation of entrance channel mass-asymmetry effect on incomplete fusion reaction for {sup 20}Ne+{sup 165}Ho system

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D., E-mail: dsinghiuac@gmail.com [Nuclear Physics Group, Inter-University Accelerator Centre, New Delhi-110 067 (India); Nuclear Physics Laboratory, Department of Physics, Aligarh Muslim University, Aligarh-202 002 (India); Ali, Rahbar [Nuclear Physics Laboratory, Department of Physics, Aligarh Muslim University, Aligarh-202 002 (India); Afzal Ansari, M., E-mail: drmafzalansari@yahoo.com [Nuclear Physics Laboratory, Department of Physics, Aligarh Muslim University, Aligarh-202 002 (India); Tomar, B.S. [Radio-chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India); Rashid, M.H. [Accelerator Physics Group, Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064 (India); Guin, R.; Das, S.K. [Radio-chemistry Group, Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064 (India)

    2012-04-01

    An experiment has been performed to explore the incomplete fusion (ICF) reaction dynamics in heavy ion induced reactions. Excitation functions (EFs) for eighteen evaporation residues (ERs) produced in the system {sup 20}Ne+{sup 165}Ho have been measured in the energy range Almost-Equal-To 88-164 MeV. Some of the ERs have significant contribution from precursor decay, which has been separated out from the measured cumulative cross-sections to get direct production cross-sections. Parameters of the statistical model code PACE-2 are optimized to reproduce the ERs populated in complete fusion reactions such as in xn and pxn channels. Using the same parameters, EFs for the residues produced in {alpha}-particle(s) emission channels have been calculated. A significant enhancement in the measured EFs of the ERs produced in {alpha}-particle(s) emission channels over the PACE-2 predictions have been observed which indicates the occurrence of incomplete fusion reaction process. In the ICF process the break-up of projectile {sup 20}Ne into {sup 4}He+{sup 16}O and/or {sup 8}Be+{sup 12}C takes place followed by fusion of one of the fragments with the target nucleus {sup 165}Ho. The present data analyses suggest that probability of incomplete fusion reaction increases with projectile energy. The ICF fraction F{sup ICF} has been estimated and found to increase with increasing mass-asymmetry [A{sub T}/(A{sub T}+A{sub P})] of the partners in entrance channel. It is also observed that critical angular momentum associated with incomplete fusion channels at higher projectile energy may be associated with Script-Small-L -values lower than that of peripheral collisions, indicating that the incomplete fusion competes with complete fusion even at angular momentum values little lower than critical angular momentum.

  17. Determination of the double-polarization observable E for the reaction γp→pπ0 in the CBELSA/TAPS experiment

    International Nuclear Information System (INIS)

    In the framework of this thesis the double-polarization observable E for the reaction γp→pπ0 was determined in the energy range of Eγ=600-2400 MeV. For this in the CBELSA/TAPS experiment ar the ELSA electron-stretcher facility a circularly polarized photon beam and a longitudinally polarized butanol target were available. Additionally for the determination of the dilution factor, which specifies the contribution of reactions on the hydrogen of the butanol, data were taken on a hydrogen target and a carbon target. In order to determine the double-polarization observable E two different methods were developed. in the first method exclusively the data on the butanol target were applied and the double-polarization observable E determined by means of the dilution factor. In the second method the sum from the cross sections at antiparallel and parallel spin orientation σ1/2 and σ3/2 was expressed by the unpolarized cross section 2σ, which was determined by means of the data on the unpolarized hydrogen target. The results of the double-polarization observable E were compared with the predictions of the three presently most usual partial-wave analyses. While the unpolarized cross section can be well described by all three predictions, already at lowest energies differences occur between the predictions and the data, so that by the extraction of this observable new informations for the partial-wave analyses can be made available.

  18. In situ observation of the reaction of tantalum with nitrogen in a laser heated diamond anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, Alexandra, E-mail: friedrich@kristall.uni-frankfurt.d [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Winkler, Bjoern; Bayarjargal, Lkhamsuren [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Juarez Arellano, Erick A. [Universidad del Papaloapan, Circuito Central 200, Parque Industrial, Tuxtepec 68301 (Mexico); Morgenroth, Wolfgang; Biehler, Jasmin; Schroeder, Florian [Institut fuer Geowissenschaften, Goethe-Universitaet Frankfurt, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany); Yan, Jinyuan; Clark, Simon M. [Advanced Light Source, Lawrence Berkeley National Laboratory, MS6R2100, 1 Cyclotron Road, Berkeley, CA 94720-8226 (United States)

    2010-07-16

    Tantalum nitrides were formed by reaction of the elements at pressures between 9(1) and 12.7(5) GPa and temperatures >1600-2000 K in the laser-heated diamond anvil cell. The incorporation of small amount of nitrogen in the tantalum structure was identified as the first reaction product on weak laser irradiation. Subsequent laser heating led to the formation of hexagonal {beta}-Ta{sub 2}N and orthorhombic {eta}-Ta{sub 2}N{sub 3}, which was the stable phase at pressures up to 27 GPa and high temperatures. No evidence was found for the presence of {epsilon}-TaN, {theta}-TaN, {delta}-TaN, Ta{sub 3}N{sub 5}-I or Ta{sub 3}N{sub 5}-II, which was predicted to be the stable phase at P>17 GPa and T=2800 K, at the P,T-conditions of this experiment. The bulk modulus of {eta}-Ta{sub 2}N{sub 3} was determined to be B{sub 0}=319(6) GPa from a 2nd order Birch-Murnaghan equation of state fit to the experimental data, while quantum mechanical calculations using the density functional theory gave a bulk modulus of B{sub 0}=348.0(9) GPa for a 2nd-order fit or B{sub 0}=339(1) GPa and B{sup '}=4.67(9) for a 3rd-order fit. The values show the large incompressibility of this high-pressure phase. From the DFT data the structural compression mechanism could be determined.

  19. Observation of the "$K^-pp$"-like structure in the $d(\\pi^+, K^+)$ reaction at 1.69 GeV/$c$

    CERN Document Server

    Ichikawa, Yudai; Fujioka, Hiroyuki; Bhang, Hyoungchan; Bufalino, Stefania; Ekawa, Hiroyuki; Evtoukhovitch, Petr; Feliciello, Alessandro; Hasegawa, Shoichi; Hayakawa, Shuhei; Honda, Ryotaro; Hosomi, Kenji; Imai, Kenichi; Ishimoto, Shigeru; Joo, Changwoo; Kanatsuki, Shunsuke; Kiuchi, Ryuta; Koike, Takeshi; Kumawat, Harphool; Matsumoto, Yuki; Miwa, Koji; Moritsu, Manabu; Naruki, Megumi; Niiyama, Masayuki; Nozawa, Yuki; Ota, Ryosuke; Sakaguchi, Atsushi; Sako, Hiroyuki; Samoilov, Valentin; Sato, Susumu; Shirotori, Kotaro; Sugimura, Hitoshi; Suzuki, Shoji; Takahashi, Toshiyuki; Takahashi, Tomonori; Tamura, Hirokazu; Tanaka, Toshiyuki; Tanida, Kiyoshi; Tokiyasu, Atsushi; Tsamalaidze, Zviadi; Roy, Bidyut; Ukai, Mifuyu; Yamamoto, Takeshi; Yang, Seongbae

    2014-01-01

    We have observed a "$K^-pp$"-like structure in the $d(\\pi^+,K^+)$ reaction at 1.69 GeV/$c$. In this reaction $\\Lambda(1405)$ hyperon resonance is expected to be produced as a doorway to form the $K^-pp$ through the $\\Lambda^*p\\rightarrow K^-pp$ process. However, most of the produced $\\Lambda(1405)$'s would escape from deuteron without secondary reactions. Therefore, coincidence of high-momentum ($>$ 250~MeV/$c$) proton(s) in large emission angles ($39^\\circ<\\theta_{lab.}<122^\\circ$) was requested to enhance the signal-to-background ratio. A broad enhancement in the proton coincidence spectra are observed around the missing-mass of 2.27 GeV/$c^2$, which corresponds to the $K^-pp$ binding energy of 95 $^{+18}_{-17}$ (stat.) $^{+30}_{-21}$ (syst.) MeV and the width of 162 $^{+87}_{-45}$ (stat.) $^{+66}_{-78}$ (syst.) MeV.

  20. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions

    International Nuclear Information System (INIS)

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  1. NanoPCR observation: different levels of DNA replication fidelity in nanoparticle-enhanced polymerase chain reactions

    Science.gov (United States)

    Shen, Cenchao; Yang, Wenjuan; Ji, Qiaoli; Maki, Hisaji; Dong, Anjie; Zhang, Zhizhou

    2009-11-01

    Nanoparticle-assisted PCR (polymerase chain reaction) technology is getting more and more attention recently. It is believed that some of the DNA recombinant technologies will be upgraded by nanotechnology in the near future, among which DNA replication is one of the core manipulation techniques. So whether or not the DNA replication fidelity is compromised in nanoparticle-assisted PCR is a question. In this study, a total of 16 different metallic and non-metallic nanoparticles (NPs) were tested for their effects on DNA replication fidelity in vitro and in vivo. Sixteen types of nanomaterials were distinctly different in enhancing the PCR efficiency, and their relative capacity to retain DNA replication fidelity was largely different from each other based on rpsL gene mutation assay. Generally speaking, metallic nanoparticles induced larger error rates in DNA replication fidelity than non-metallic nanoparticles, and non-metallic nanomaterials such as carbon nanopowder or nanotubes were still safe as PCR enhancers because they did not compromise the DNA replication fidelity in the Taq DNA polymerase-based PCR system.

  2. Observation of the Exclusive Reaction e+e- -> phi eta at sqrt{s}=10.58 GeV

    CERN Document Server

    Aubert, B; Boutigny, D; Karyotakis, Yu; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Graugès-Pous, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes-Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Tackmann, K; Wenzel, W A; Del Amo-Sánchez, P; Barrett, M; Harrison, T J; Hart, A J; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schröder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Asgeirsson, D J; Çuhadar-Dönszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M A; Martin, E C; Röthel, W; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Long, O; Shen, B C; Zhang, L; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Williams, D C; Wilson, M G; Winstrom, L O; Albert, J; Chen, E; Cheng, C H; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Thiebaux, C; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Nikolich, M B; Panduro-Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F R; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; George, K A; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flächer, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Salvatore, F; Wren, A C; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Williams, J C; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Kim, H; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, Gallieno; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; LoSecco, J M; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Jackson, P D; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Ter-Antonian, R; Wong, Q K; Blount, N L; Brau, J E; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Potter, C T; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; Hartfiel, B L; Leruste, P; Malcles, J; Ocariz, J; Gladney, L; Biasini, M; Covarelli, R; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Judd, D; Wagoner, D E; Biesiada, J; Elmer, P; Lau, Y P; Lü, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; Del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Safai-Tehrani, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; Franek, B; Olaiya, E O; Ricciardi, S; Wilson, F F; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Legendre, M; Vasseur, G; Yéche, C; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Halyo, V; Hast, C; Hrynóva, T; Innes, W R; Kelsey, M H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Lüth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Vavra, J; Van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martínez-Vidal, F; Oyanguren, A; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R V; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Mellado, B; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H; al, et

    2006-01-01

    We report the observation of $\\e^+e^-\\to \\phi\\eta$ near $\\sqrt{s}$ = 10.58 GeV with 6.5 $\\sigma$ significance in the $K^+K^-\\gamma\\gamma$ final state in a data sample of 224 $fb^{-1}$ collected by the BaBar experiment at the PEP-II $e^+e^-$ storage rings. We measure the restricted radiation-corrected cross section to be $\\sigma(\\e^+e^- \\to \\phi \\eta) =

  3. Calibración y puesta en marcha de una nueva máquina de ensayo para hormigón afectado por la reacción álcali-árido

    OpenAIRE

    Acosta Collell, Ivan

    2012-01-01

    [ANGLÈS] The present document is about the calibration and tuning of a machine for testing the expansion induced by alkali-silica reaction in concrete specimens affected under triaxial stress states. The alkali-silica reaction (ASR) has its origin in the combination of reactive silica present in some aggregates, with the hydroxyl ions normally present in abundance in the water of the pores of concrete. If there are conditions with sufficient water, the subsequent reactions l...

  4. In-situ scanning electron microscopy observations of Li plating and stripping reactions at the lithium phosphorus oxynitride glass electrolyte/Cu interface

    Science.gov (United States)

    Sagane, Fumihiro; Shimokawa, Ryosuke; Sano, Hikaru; Sakaebe, Hikari; Iriyama, Yasutoshi

    2013-03-01

    Morphology variations during electrochemical lithium plating-stripping reactions at the lithium phosphorus oxynitride glass electrolyte (LiPON)/copper current collector (Cu) interface are observed in-situ by scanning electron microscopy (SEM). This in-situ SEM observation shows dynamically that the plating reactions at 50 μA cm-2 distribute initial lithium growth sites sparsely at the LiPON/Cu interface, later, local lithium growth occurs from the pre-plated sites through the Cu film, and finally, most of the precipitated lithium grows to be needle-shape with the height of micron order. This local growth rate attains to be 6.8 mA cm-2, about 100 times higher value than applied one. When those precipitated lithium are stripped at 50 μA cm-2, core region of each precipitate is mostly stripped but its degree depends on the length of the precipitate. This dependency will arise from the diffusivity of Li. When this stripping current density is increased to 500 μA cm-2, the coulomb efficiency is further decreased. In-situ SEM observation shows that plated lithium around the interface becomes thin preferentially while that far away from the interface (upper side of plated lithium) remains unchanged. This will isolate most of precipitate lithium from LiPON film electrically, leading to further decreasing of the coulomb efficiency.

  5. In situ observation of eutectoid reaction forming a PbTe-Sb₂Te₃ thermoelectric nanocomposite by synchrotron X-ray diffraction

    OpenAIRE

    Ikeda, Teruyuki; Toberer, Eric S; Ravi, Vilupanur A.; Snyder, G. Jeffrey; Aoyagi, Shinobu; Nishibori, Eiji; Sakata, Makoto

    2009-01-01

    In situ high-temperature powder X-ray diffraction experiments have been performed on performed on Pb10.5Sb6Te57.9 using using a synchrotron X-ray source to observe the eutectoid reaction from Pb2Sb6Te11 to PbTe and Sb2Te3. Molar fractions of the constituent phases and fraction transformed were obtained as functions of time. The experimental fraction transformed vs. time curve were well fitted by the Kolmogorov–Johnson–Mehl–Avrami equation with an Avrami index n = 1.4. The small n value sugges...

  6. Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate.

    Science.gov (United States)

    Portu, Agustina; Rossini, Andrés Eugenio; Thorp, Silvia Inés; Curotto, Paula; Pozzi, Emiliano César Cayetano; Granell, Pablo; Golmar, Federico; Cabrini, Rómulo Luis; Martin, Gisela Saint

    2015-08-01

    The distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an "imprint" of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013 cm-2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines and in vitro evaluation of the effect of diverse boron compounds are feasible with this methodology. PMID:26155721

  7. First measurement of the polarization observable E in the p→(γ→,π+n reaction up to 2.25 GeV

    Directory of Open Access Journals (Sweden)

    S. Strauch

    2015-11-01

    Full Text Available First results from the longitudinally polarized frozen-spin target (FROST program are reported. The double-polarization observable E, for the reaction γ→p→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn–Gatchina, Jülich–Bonn, and SAID groups.

  8. First Measurement of the Polarization Observable E in the $\\vec p(\\vec \\gamma,\\pi^+)n$ Reaction up to 2.25 GeV

    CERN Document Server

    Strauch, S; Döring, M; Klempt, E; Nikonov, V A; Pasyuk, E; Rönchen, D; Sarantsev, A V; Strakovsky, I; Workman, R; Adhikari, K P; Adikaram, D; Anderson, M D; Pereira, S Anefalos; Anisovich, A V; Badui, R A; Ball, J; Batourine, V; Battaglieri, M; Bedlinskiy, I; Benmouna, N; Biselli, A S; Brock, J; Brooks, W K; Burkert, V D; Cao, T; Carlin, C; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Compton, N; Contalbrigo, M; Cortes, O; Crede, V; Dashyan, N; D'Angelo, A; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dugger, M; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Forest, T A; Fradi, A; Gevorgyan, N; Ghandilyan, Y; Giovanetti, K L; Girod, F X; Glazier, D I; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Harrison, N; Hattawy, M; Hicks, K; Ho, D; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Keith, C D; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, F J; Kubarovsky, V; Kuhn, S E; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; McKinnon, B; Meekins, D G; Meyer, C A; Mokeev, V; Montgomery, R A; Moody, C I; Moutarde, H; Movsisyan, A; Munevar, E; Camacho, C Munoz; Nadel-Turonski, P; Net, L A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Park, K; Peng, P; Phelps, W; Phillips, J J; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Raue, B A; Ripani, M; Ritchie, B G; Rizzo, A; Rosner, G; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Seely, M L; Senderovich, I; Sharabian, Y G; Simonyan, A; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Stoler, P; Stepanyan, S; Sytnik, V; Taiuti, M; Tian, Ye; Trivedi, A; Tucker, R; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D P; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2015-01-01

    First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\\vec \\gamma \\vec p \\to \\pi^+n$, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, J\\"ulich, and SAID groups.

  9. Novel observations of dynamic crystallography in the solid-state LiBH4/MgH2 hydrogen absorption reaction

    International Nuclear Information System (INIS)

    The Lithium hydride/magnesium di-boride system has been the subject of much investigation due to its potential in solving the mobile hydrogen storage problem. While its weight (11.4 wt%) and volume densities of hydrogen are favourable, it has been found to react at unfavourable temperatures. Performance improvements have been made since through the use of additives and micro-/nano-structuring. In order to make neutron diffraction viable, magnesium di-boride was synthesised using 11 B enriched boron. This was then used as a constituent in the samples, which consisted primarily of a 2:1 molar ratio LiH to MgB2, some an additives 5 at% (VCI3). In-situ time-of-flight neutron diffraction was undertaken (Polaris, ISIS, United Kingdom) for both the forward and back reaction: 2LiH + MgB2 + 4H2 ↔ 2LiBH4 + MgH2. The absorption was performed at the temperature of 250°C so as to have the products of the reaction remain solid, and thus measurable using diffraction. The reaction was observed to progress, although not to completion due to time restrictions. A crystallographic change was observed in the formed lithium borohydride; a lattice parameter shifting as a function of hydrogen content within the sample. Attenuation correction was performed, applying the model that Gray et al proposed for masked TOF cells. For the actual application this model, assumptions and approximations were necessary in this instance.

  10. Observation of 511 keV peak high count rate in studying (n,x) and (g,x) reactions on terbium

    CERN Document Server

    Kadenko, I

    2011-01-01

    Experimental investigation of (n, x) and (g, x) reactions on Tb-159 with activation technique was carried out. Tb specimens of natural composition were irradiated with (d-d) and (d-t) neutrons using NG-300 neutron generator. Additionally the series of experiments were performed with application of M-30 microtrone as a source of electrons for bremsstrahlung spectra production with end point energies 7.5, 9.5, 11, 11.5, 12, 12.5, 16.5, and 18.5 MeV. Instrumental spectra of Tb specimens were measured with HPGe and Ge(Li) spectrometers. Within the main scope of nuclear reactions research and accurate {\\gamma}-spectrometry of Tb specimens a high count rate in 511 keV {\\gamma}-line peak was observed. The first-priority analysis of Tb specimen impurities was done with further attempts to explain a result of observations with reference to the specific nuclear properties of Tb which could appear due to complex GDR structure. The energy threshold of the process detected was determined around 12.2 MeV. The lower estimat...

  11. Dynamical observation of lithium insertion/extraction reaction during charge-discharge processes in Li-ion batteries by in situ spatially resolved electron energy-loss spectroscopy.

    Science.gov (United States)

    Shimoyamada, Atsushi; Yamamoto, Kazuo; Yoshida, Ryuji; Kato, Takehisa; Iriyama, Yasutoshi; Hirayama, Tsukasa

    2015-12-01

    All-solid-state Li-ion batteries (LIBs) with solid electrolytes are expected to be the next generation devices to overcome serious issues facing conventional LIBs with liquid electrolytes. However, the large Li-ion transfer resistance at the electrode/solid-electrolyte interfaces causes low power density and prevents practical use. In-situ-formed negative electrodes prepared by decomposing the solid electrolyte Li(1+x+3z)Alx(Ti,Ge)(2-x)Si(3z)P(3-z)O12 (LASGTP) with an excess Li-ion insertion reaction are effective electrodes providing low Li-ion transfer resistance at the interfaces. Prior to our work, however, it had still been unclear how the negative electrodes were formed in the parent solid electrolytes. Here, we succeeded in dynamically visualizing the formation by in situ spatially resolved electron energy-loss spectroscopy in a transmission electron microscope mode (SR-TEM-EELS). The Li-ions were gradually inserted into the solid electrolyte region around 400 nm from the negative current-collector/solid-electrolyte interface in the charge process. Some of the ions were then extracted in the discharge process, and the rest were diffused such that the distribution was almost flat, resulting in the negative electrodes. The redox reaction of Ti(4+)/Ti(3+) in the solid electrolyte was also observed in situ during the Li insertion/extraction processes. The in situ SR-TEM-EELS revealed the mechanism of the electrochemical reaction in solid-state batteries. PMID:26337787

  12. Complete set of polarization transfer observables for the 16O(p-vector, n-vector)16F reaction at 296 MeV and 0 deg

    International Nuclear Information System (INIS)

    We report measurements of the cross section and a complete set of polarization transfer observables for the 16O(p-vector, n-vector)16F reaction at a bombarding energy of Tp = 296 MeV and a reaction angle of θlab = 0 deg. The data are compared with distorted-wave impulse approximation calculations employing the large configuration-space shell-model (SM) wave functions. The well-known Gamow-Teller and spin-dipole (SD) states at excitation energies of Ex π = 2- state at Ex = 5.86 MeV. The SD resonance at Ex ≅ 9.5 MeV appears to have more Jπ = 2- strength than Jπ = 1- strength, consistent with the calculations. The data show significant strength in the spin-longitudinal polarized cross section IDL(0 deg.) at Ex ≅ 15 MeV, which indicates the existence of the Jπ = 0- SD resonance as predicted in the SM calculations.

  13. Observation of high-j quasiparticle states in Cm249 by in-beam γ-ray spectroscopy using heavy-ion transfer reactions

    Science.gov (United States)

    Ishii, T.; Makii, H.; Asai, M.; Tsukada, K.; Toyoshima, A.; Matsuda, M.; Makishima, A.; Shigematsu, S.; Kaneko, J.; Shizuma, T.; Toume, H.; Hossain, I.; Kohno, T.; Ogawa, M.

    2008-11-01

    We have measured de-excitation γ rays in Cm249 populated by one-neutron stripping reactions with a Cm248 target and 162-MeV O16, 162-MeV O18, and 120-MeV C13 beams. γ rays in Cm249 were identified by measuring kinetic energies of outgoing particles using Si ΔE-E detectors. It was demonstrated that high-j orbitals were selectively populated in the (O16, O15) reaction having a large negative Q value. We have observed eight quasiparticle states above the deformed shell gap of N=152. The 1/2+[620], 1/2-[750], and 7/2+[613] bands were extended up to 19/2+, 19/2-, and 13/2+ states, respectively. We have established the 9/29/2+[615] state at 526 keV, the 9/29/2+[604] state with a short life of T1/2≪2 ps at 1030 keV, and the 11/211/2-[725] state with T1/2=19(1) ns at 375 keV. Furthermore, the 17/21/2+[880] state, having a large component of the k17/2 spherical single-particle state, has been identified at 1505 keV. We discuss the properties of those quasiparticle states in the framework of a deformed shell model.

  14. Observation of high-j quasiparticle states in 249Cm by in-beam γ-ray spectroscopy using heavy-ion transfer reactions

    International Nuclear Information System (INIS)

    We have measured de-excitation γ rays in 249Cm populated by one-neutron stripping reactions with a 248Cm target and 162-MeV 16O, 162-MeV 18O, and 120-MeV 13C beams. γ rays in 249Cm were identified by measuring kinetic energies of outgoing particles using Si ΔE-E detectors. It was demonstrated that high-j orbitals were selectively populated in the (16O, 15O) reaction having a large negative Q value. We have observed eight quasiparticle states above the deformed shell gap of N=152. The 1/2+[620], 1/2-[750], and 7/2+[613] bands were extended up to 19/2+, 19/2-, and 13/2+ states, respectively. We have established the 9/2 9/2+[615] state at 526 keV, the 9/2 9/2+[604] state with a short life of T1/2-[725] state with T1/2=19(1) ns at 375 keV. Furthermore, the 17/2 1/2+[880] state, having a large component of the k17/2 spherical single-particle state, has been identified at 1505 keV. We discuss the properties of those quasiparticle states in the framework of a deformed shell model

  15. Complete set of polarization transfer observables for the ${}^{16}{\\rm O}(\\vec{p},\\vec{n}){}^{16}{\\rm F}$ reaction at 296 MeV and 0 degrees

    CERN Document Server

    Wakasa, T; Takaki, M; Dozono, M; Hatanaka, K; Ichimura, M; Noro, T; Okamura, H

    2011-01-01

    We report measurements of the cross section and a complete set of polarization transfer observables for the ${}^{16}{\\rm O}(\\vec{p},\\vec{n}){}^{16}{\\rm F}$ reaction at a bombarding energy of $T_p$ = 296 MeV and a reaction angle of $\\theta_{\\rm lab}$ = $0^{\\circ}$. The data are compared with distorted-wave impulse approximation calculations employing the large configuration-space shell-model (SM) wave functions. The well-known Gamow-Teller and spin-dipole (SD) states at excitation energies of $E_x$ $\\lesssim$ 8 MeV have been reasonably reproduced by the calculations except for the spin--parity $J^{\\pi}$ = $2^-$ state at $E_x$ = 5.86 MeV. The SD resonance at $E_x$ $\\simeq$ 9.5 MeV appears to have more $J^{\\pi}$ = $2^-$ strength than $J^{\\pi}$ = $1^-$ strength, consistent with the calculations. The data show significant strength in the spin-longitudinal polarized cross section $ID_L(0^{\\circ})$ at $E_x$ $\\simeq$ 15 MeV, which indicates existence of the $J^{\\pi}$ = $0^-$ SD resonance as predicted in the SM calcul...

  16. High-resolution electron microscopy observation and dislocation reaction mechanism of fivefold twinning in a Cu-rich precipitate in a cold rolled ferritic steel containing copper

    International Nuclear Information System (INIS)

    Ferritic steels containing copper have been studied as model systems for clusters/precipitate formation in reactor pressure vessel steels. The samples were aged at 400 °C for 4000 h and subsequently cold rolled to 30% reduction at room temperature. The microstructural characteristics of the samples were analyzed using high-resolution transmission electron microscopy. Direct evidence was found that the fivefold twinning occurs via simultaneous emission of two Shockley partial dislocations from two particular α-Fe/Cu interfaces, and then the pileup tips of the twofold twin. - Highlights: • Fivefold twin is observed in a Cu-rich precipitate in cold rolled ferritic steels. • A dislocation reaction mechanism for the fivefold twin formation is proposed. • Two particular mismatching α-Fe/Cu-rich precipitate interfaces play a critical role

  17. Observations of motor reactions to ions, hormones, pharmaceuticals, electrical stimulation and X irradiation in intraoperatively removed human genital preparations (myometrium, tuba uterina and genital vessels)

    International Nuclear Information System (INIS)

    Elementary physiological, pharmacological and radiological characteristics of isolated genital preparations - myometrium, tuba uterina and genital vessels - from human op material were compared and analysed. The basal tone and the spontaneous contractile activity were dependent on the sodium, potassium and calcium chloride concentration in the nutritive solution. Observations of the motor reactions of the preparations of myometrium and tuba uterina to hormones and their antagonists confirm or indicate the presence of specific hormone receptors. X-radiation caused a tonic contraction and changes in the spontaneous contractile activity in myometrium preparations. Uterine and ovarian vessels reacted to irradiated with definite and often enduring tonic contractions. Theophyllin, a substance with an inhibiting affect on phosphodiesterase, which leads to an increase in intracellular cAMP concentration, works against the X-radiation influence. (MBC)

  18. Observation of a New JPC = 1-+ Exotic State in the Reaction π-p → π+ π-π- p at 18 GeV/c

    International Nuclear Information System (INIS)

    A partial-wave analysis of the reaction π-p→π+π- π-p at 18 GeV/c has been performed on a data sample of 250000 events obtained by Brookhaven experiment E852. The expected JPC=1++a1(1260) , 2++a2(1320) , and 2-+π2(1670) resonant states are clearly observed. The exotic JPC=1-+ wave produced in the natural parity exchange processes shows distinct resonancelike phase motion at about 1.6 GeV/c2 in the ρπ channel. A mass-dependent fit results in a resonance mass of 1593±8+29-47 MeV /c2 and a width of 168±20+150-12 MeV /c2 . copyright 1998 The American Physical Society

  19. On the structure observed in the in-flight ${}^{3}\\text{He} ( K^{-} , \\, \\Lambda p ) n$ reaction at J-PARC

    CERN Document Server

    Sekihara, Takayasu; Ramos, Angels

    2016-01-01

    A theoretical investigation is done to clarify the origin of the peak structure observed near the $K^{-} p p$ threshold in the in-flight ${}^{3}\\text{He} ( K^{-}, \\, \\Lambda p ) n$ reaction of the J-PARC E15 experiment, which could be a signal of the lightest kaonic nuclei, that is, the $\\bar{K} N N (I=1/2)$ state. For the investigation, we evaluate the $\\Lambda p$ invariant mass spectrum assuming two possible scenarios to interpret the experimental peak. One assumes that the $\\Lambda (1405)$ resonance is generated after the emission of an energetic neutron from the absorption of the initial $K^-$, not forming a bound state with the remaining proton. This uncorrelated $\\Lambda (1405) p$ system subsequently decays into the final $\\Lambda p$. The other scenario implies that, after the emission of the energetic neutron, a $\\bar{K} N N$ bound state is formed, decaying eventually into a $\\Lambda p$ pair. Our results show that the experimental signal observed in the in-flight ${}^{3}\\text{He} ( K^{-} , \\, \\Lambda p...

  20. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  1. Investigation of the high energy statistical γ-ray spectrum observed in the 16O + 144Nd reaction and of its influence on the resulting 160Er deexcitation

    International Nuclear Information System (INIS)

    We have studied the high energy statistical γ-ray spectrum observed in the fusion-evaporation reaction 16O + 144Nd → 160Er* and the influence of the γ-strength function on the production cross section of the evaporation residues. It was possible to reproduce the measured statistical γ-ray spectra in the framework of the statistical model by assuming that at all excitation energies, the dipole strength function has a lorentzian shape characteristic of the electric dipole giant resonance. However, our analysis demonstrates that there is a very strong correlation between the parameters of this strength function and the level density parameter. The comparison of the statistical γ-ray spectra obtained at three different excitation energies shows that the high energy part of the spectra comes mainly from the first steps of the decay cascade in direct competition with particle evaporation. This is in agreement with the prediction of the statistical model. By measuring both the statistical γ-ray spectrum and the evaporation residues cross section for the same reaction, it was possible to show that using an energy dependent γ-strength function which describes the measured γ ray spectrum improves the description of the evaporation residues cross section by the statistical model as compared to the results of more standard calculations where an energy independent dipole strength function is used. This work shows that the study of the γ-strength function at high energy could be a powerful probe of the nuclei far from the yrast line but that to realize this, it will be necessary to improve our knowledge of the level density proprieties at high excitation energy. (author)

  2. Observation of exotic meson production in the reaction π- p → η(prime) π- p at 18 GeV/c

    International Nuclear Information System (INIS)

    An amplitude analysis of an exclusive sample of 5765 events from the reaction π- p → η(prime)π- p at 18 GeV/c is described. The η(prime)π- production is dominated by natural parity exchange and by three partial waves: those with JPC = 1-+, 2++, and 4++. A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to η(prime)π-. The dominant, exotic (non-q(bar q)) 1-+ partial wave is shown to be resonant with a mass of 1.597 ± 0.010-0.010+0.045 GeV/c2 and a width of 0.340 ± 0.040 ± 0.050 GeV/c2. This exotic state, the π1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states

  3. Observation of a dynamical deformation and informations about the density levels in the sequential reaction 12C(28Si, 2 alphas)32S

    International Nuclear Information System (INIS)

    We have measured the reaction 12C+28Si leading to the low lying states of 32S by emission of 8Be or of two sequential α particles using a 28Si beam with energies from 60 to 90 MeV and different detection techniques and geometries. The relative intensities of the different final states and the integrated excitation functions of sequential α particles are in good agreement with statistical model predictions. That means we are in presence of sequential α particle decay of the 40Ca compound nucleus. We extend the statistical model code CASCADE in order to calculate differential cross sections. The code CORANG was written for the calculation of the angular correlation of the two α particles taking in account all the angular momenta of the intermediate 36Ar. By comparing the measured angular correlations with the predictions of our calculation we found evidence for strong deformation effects in the first step of the sequential decay. We observed structures at high excitation energy in 36Ar spectra. The coherence width of 40Ca has been obtained through the analysis of cross-correlations of the 36Ar energy spectra at different incident energies. In addition to the expected width there is an indication for the presence of a second coherence width wich could correspond to anomalous long living compound nucleus states. The averaging over Ericson fluctuations permits to get the structures corresponding only to level density effects in 36Ar

  4. Measurement of the $np \\to np\\pi^0\\pi^0$ Reaction in Search for the Recently Observed $d^*(2380)$ Resonance

    CERN Document Server

    Adlarson, P; Bardan, W; Bashkanov, M; Bergmann, F S; Berłowski, M; Bhatt, H; Bondar, A; Büscher, M; Calén, H; Ciepał, I; Clement, H; Coderre, D; Czerwiński, E; Demmich, K; Doroshkevich, E; Engels, R; Erven, A; Erven, W; Eyrich, W; Fedorets, P; Föhl, K; Fransson, K; Goldenbaum, F; Goslawski, P; Goswami, A; Grigoryev, K; Gullström, C --O; Hauenstein, F; Heijkenskjöld, L; Hejny, V; Höistad, B; Hüsken, N; Jarczyk, L; Johansson, T; Kamys, B; Kemmerling, G; Khan, F A; Khoukaz, A; Kirillov, D A; Kistryn, S; Kleines, H; Kłos, B; Krzemień, W; Kulessa, P; Kupść, A; Kuzmin, A; Lalwani, K; Lersch, D; Lorentz, B; Magiera, A; Maier, R; Marciniewski, P; Mariański, B; Mikirtychiants, M; Morsch, H --P; Moskal, P; Ohm, H; Ozerianska, I; del Rio, E Perez; Piskunov, N M; Podkopał, P; Prasuhn, D; Pricking, A; Pszczel, D; Pysz, K; Pyszniak, A; Ritman, J; Roy, A; Rudy, Z; Sawant, S; Schadmand, S; Sefzick, T; Serdyuk, V; Shwartz, B; Siudak, R; Skorodko, T; Skurzok, M; Smyrski, J; Sopov, V; Stassen, R; Stepaniak, J; Stephan, E; Sterzenbach, G; Stockhorst, H; Ströher, H; Szczurek, A; Täschner, A; Trzciński, A; Varma, R; Wagner, G J; Wolke, M; Wrońska, A; Wüstner, P; Wurm, P; Yamamoto, A; Zabierowski, J; Zieliński, M J; Zink, A; Złomańczuk, J; Żuprański, P; Żurek, M

    2014-01-01

    Exclusive measurements of the quasi-free $np \\to np\\pi^0\\pi^0$ reaction have been performed by means of $dp$ collisions at $T_d$ = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $\\sqrt s$ = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated $d^*(2380)$ resonance. Adding the $d^*$ resonance amplitude to that for the conventional processes leads to a reasonable description of the data. The observed resonance effect in the total cross section is in agreement with the predictions of F\\"aldt and Wilkin as well Albadajedo and Oset. The ABC effect, {\\it i.e.} the low-mass enhancement in the $\\pi^0\\pi^0$-invariant mass spectrum, is found to be very modest - if present at all, which might pose a problem to some of its interpretations.

  5. Variation of adverse drug reaction profile of platinum-based chemotherapy with body mass index in patients with solid tumors: An observational study

    Directory of Open Access Journals (Sweden)

    Dattatreyo Chatterjee

    2014-01-01

    Full Text Available Objectives: Toxicity of cancer chemotherapy may be affected by nutritional status of patients which is reflected in the body mass index (BMI. We sought to assess whether the adverse drug reaction (ADR profile of platinum-based chemotherapy varies with BMI status. Materials and Methods: Adult patients of either sex, suffering from a solid tumor (lung, head and neck, ovary, gall bladder, stomach, colon and started on platinum-based chemotherapy as initial treatment were included. BMI at chemotherapy commencement was obtained from medical records. Events were recorded and graded as per Eastern Co-operative Oncology Group Common Toxicity Criteria-patients′ complaints; clinically evident signs and laboratory reports were considered. Frequencies of individual adverse events were compared between low BMI (<18.5 kg/m 2 and satisfactory BMI groups. Similar comparisons were done for events with grades 2 or 3 severities. Results: A total of 50 patients were observed over a 3-month period of whom 17 (34% belonged to the low BMI group. Nausea, vomiting, diarrhea, stomatitis, anemia, alopecia, tinnitus and paresthesia were the commonly observed ADRs. The frequencies of anemia (P = 0.152 and vomiting (P = 0.140 and severity of grades of nausea (P = 0.066, anemia (P = 0.120 and paresthesia (P = 0.128 showed a higher trend in the low BMI group though differences were not statistically significant. The frequencies of tinnitus (P = 0.021 and paresthesia overall (P = 0.036 were significantly higher in the low BMI group. Conclusion: ADR profile of primary platinum-based chemotherapy appears to be partly influenced by BMI. This suggests the importance of maintaining adequate nutrition in patients and the need for greater vigilance in those with low BMI.

  6. Prevalence of acute adverse reactions to gadobutrol-A highly concentrated macrocyclic gadolinium chelate: Review of 14,299 patients from observational trials

    International Nuclear Information System (INIS)

    Objective: To determine the safety and tolerability of gadobutrol in a large number of non-selected patients from routine clinical radiology practices. Materials and methods: Six prospectively planned, observational surveillance studies were conducted at more than 300 institutions in Europe and Canada from 2000 to 2007. Demographic and medical status data, details of the diagnostic procedure, contrast agent administration and adverse drug reaction (ADR) data were collected using a standardized questionnaire. Results: A total of 14,299 patients were enrolled. The mean age of the patients was 53.7 years; 1.3% of the patients were <18 years old and 40.8% were 60 years or older. The body regions most frequently examined were head/neck/brain (54.3%), followed by spine (7.2%), pelvis/joints/limbs (6.7%) and multiple body regions (6.4%). Gadobutrol-enhanced magnetic resonance angiography (MRA) was performed in 14.7% of patients. Overall, the mean volume of gadobutrol administered for contrast-enhanced magnetic resonance imaging was 12 mL (0.16 mmol gadolinium [Gd]/kg body weight [BW]; mean BW: 75.5 kg), whereas for contrast-enhanced MRA the mean volume was 15.7 mL (0.21 mmol Gd/kg BW). Seventy-eight of the 14,299 patients (0.55%) reported at least one ADR. Two (0.01%) serious ADRs were reported. The most frequently reported ADR was nausea, which occurred in 36 patients (0.25%). Conclusion: Gadobutrol 1.0 M is very well tolerated and has a good safety profile. The occurrence of ADRs observed following the intravenous injection of gadobutrol is comparable with the published data of other Gd-based contrast agents.

  7. Prevalence of acute adverse reactions to gadobutrol-A highly concentrated macrocyclic gadolinium chelate: Review of 14,299 patients from observational trials

    Energy Technology Data Exchange (ETDEWEB)

    Forsting, Michael, E-mail: michael.forsting@uni-due.d [Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstr. 55, 45122 Essen (Germany); Palkowitsch, Petra, E-mail: petra.palkowitsch@bayerhealthcare.co [Bayer Schering Pharma AG, Medical Affairs Europe Diagnostic Imaging, Muellerstr. 178, 13353 Berlin (Germany)

    2010-06-15

    Objective: To determine the safety and tolerability of gadobutrol in a large number of non-selected patients from routine clinical radiology practices. Materials and methods: Six prospectively planned, observational surveillance studies were conducted at more than 300 institutions in Europe and Canada from 2000 to 2007. Demographic and medical status data, details of the diagnostic procedure, contrast agent administration and adverse drug reaction (ADR) data were collected using a standardized questionnaire. Results: A total of 14,299 patients were enrolled. The mean age of the patients was 53.7 years; 1.3% of the patients were <18 years old and 40.8% were 60 years or older. The body regions most frequently examined were head/neck/brain (54.3%), followed by spine (7.2%), pelvis/joints/limbs (6.7%) and multiple body regions (6.4%). Gadobutrol-enhanced magnetic resonance angiography (MRA) was performed in 14.7% of patients. Overall, the mean volume of gadobutrol administered for contrast-enhanced magnetic resonance imaging was 12 mL (0.16 mmol gadolinium [Gd]/kg body weight [BW]; mean BW: 75.5 kg), whereas for contrast-enhanced MRA the mean volume was 15.7 mL (0.21 mmol Gd/kg BW). Seventy-eight of the 14,299 patients (0.55%) reported at least one ADR. Two (0.01%) serious ADRs were reported. The most frequently reported ADR was nausea, which occurred in 36 patients (0.25%). Conclusion: Gadobutrol 1.0 M is very well tolerated and has a good safety profile. The occurrence of ADRs observed following the intravenous injection of gadobutrol is comparable with the published data of other Gd-based contrast agents.

  8. Limitations of the mean-field description for nuclei in the Pb-region, observed with the (e,e'p) reaction

    International Nuclear Information System (INIS)

    The aim of the high-resolution electron induced quasi-elastic proton knockout experiments is to determine absolute occupation numbers for the valence-proton orbits of 208Pb and to check whether the predicted occupancies of 70 to 80% can be experimentally verified or that the general trend of the much lower spectroscopic factors observed in the lighter nuclei continues. Therefore the spectral function of 208Pb is mapped out with the (e,e'p) reaction in a missing-momentum range between -50 and 300 MeV/c. The spectroscopic factors for the known discrete hole states in 207Tl at excitation energies of 0.0 (1/2+), 0.35 (3/2+), 1.35 (11/2-), 1.67 (5/2+) and 3.48 MeV (7/2+) are determined by comparison with calculated (CDWIA) momentum densities and an l-decomposition is performed for the continuum. Since rather small spectroscopic factors were expected and bearing in mind the large implications for the theory, an additional calibration of the spectroscopic factors deduced from the (e,e'p) data was needed. Such a calibration possibility was found for the 3s1/2 proton orbit in 208Pb, which according to the shell-model picture is just filled. Two relative (e,e'p) experiments were performed on the pairs 205Tl/206Pb and 206Pb/208Pb which allowed the determination of the absolute 3s1/2 proton occupation in 205Tl, 206Pb and 208Pb. 47 refs.; 23 tabs

  9. Sodium concrete reactions

    International Nuclear Information System (INIS)

    The data from an extensive series of sodium/concrete reaction tests are presented and mechanisms by which the reactions proceed are analyzed. The results indicate water transport and the resulting sodium/water reaction dominate both the chemical energy release and H2 generation. A mechanism which explains the limited penetration of concrete observed in most of these tests is proposed

  10. Further studies on cation clock reactions in glycosylation: observation of a configuration specific intramolecular sulfenyl transfer and isolation and characterization of a tricyclic acetal.

    Science.gov (United States)

    Huang, Min; Furukawa, Takayuki; Retailleau, Pascal; Crich, David; Bohé, Luis

    2016-06-01

    The use of the 2-O-(2-trimethylsilylmethallyl) group as intramolecular nucleophile and cation clock reaction in the glucopyranose series depends on the nature of the glycosyl donor. As previously reported, with trichloroacetimidates the anticipated intramolecular Sakurai reaction proceeds efficiently and is an effective clock, whereas with sulfoxides complications arise. The source of these complications is now shown to be an intramolecular sulfenyl transfer reaction between the tethered allylsilane and the activated sulfoxide. These results illustrate how a different unimolecular clock reaction may be required for a given cation when it is generated from different donors in order to avoid side reactions. The synthesis and cyclization of a 2-O-(3-hydroxypropyl) glucopyranosyl sulfoxide leading on activation to the formation of a trans-fused acetal is also described. The formation of this crystallographically-established trans-fused acetal is discussed in terms of the high effective concentration of the intramolecular nucleophile which leads to a high degree of a SN2 character in the displacement of the α-glucosyl triflate or at the level of the corresponding α-CIP. The possible use of such intramolecular alcohols as clock reactions and their limitations is discussed. PMID:27085740

  11. New observation on a class of old reactions:Chemoselectivity for the solvent-free reaction of aromatic aldehydes with alkylketones catalyzed by a double-component inorganic base system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Solvent-free reactions of aromatic aldehydes with three representative ketones,including acetophenone,acetone and cyclohexanone,have been examined under the catalysis of a low-cost inorganic base system consisting of NaOH and K2CO3.It was found that the chemoselectivity of the reactions is in close relationship with the composition of the reactants and the doublecomponent catalyst.Under the optimized experimental conditions,1,2,3,4,5-pentasubstituted cyclohexanols,α,β-unsaturated ketones and Claisen-Schmidt bicondensation products were obtained in high yields.Two Kostanecki’s triketones were separated,The composition and structure were affirmed by X-ray crystallographic analysis.

  12. Direct observation of rate determining step for Nd2NiO4+δ SOFC cathode reaction by operando electrochemical XAS

    International Nuclear Information System (INIS)

    The oxygen chemical potential of dense Nd2NiO4+δ thin films on Zr0.92Y0.08O1.96 electrolyte was investigated by operando X-ray absorption spectroscopy (XAS) measurements. Operando XAS at the Ni K-edge was measured under an applied voltage and various oxygen partial pressures at high temperature to simulate the operating conditions of solid oxide fuel cells (SOFCs). The absorption edge energy under various polarizations is similar to those measured under equivalent oxygen partial pressures under open circuit condition. Thus, the oxygen chemical potential changes drastically at the electrode/gas interface and the rate-determining step of this model system is the surface reaction. This study provides direct evidence for the rate-determining step of the SOFC cathode reaction. (author)

  13. Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

    OpenAIRE

    Kaya, Sarp; Malacrida, Paolo; Casalongue, Hernan G. Sanchez; Masini, Federico; Hernandez-Fernandez, Patricia; Deiana, Davide; Ogasawara, Hirohito; Stephens, Ifan E. L.; Nilsson, Anders; Chorkendorff, Ib

    2015-01-01

    Size-selected 9 nm PtxY nanoparticles have recently shown an outstanding catalytic activity for the oxygen reduction reaction, representing a promising cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Studying their electrochemical dealloying is a fundamental step towards the understanding of both their activity and stability. Herein, size-selected 9 nm PtxY nanoparticles have been deposited on the cathode side of a PEMFC specifically designed for in situ ambient pressure X-...

  14. Multi-state stochastic hotchpotch model gives rise to the observed mesoscopic behaviour in the non-stirred Belousov--Zhabotinsky reaction

    CERN Document Server

    Štys, Dalibor; Zhyrova, Anna; Rychtáriková, Renata; Štys, Kryštof M; Náhlík, Tomáš

    2016-01-01

    Mesoscopic dynamics of self-organized structures is the most important aspect in the description of complex living systems. The Belousov--Zhabotinsky (B--Z) reaction is in this respect a convenient testbed because it represents a prototype of chemical self-organization with a rich variety of emergent wave-spiral patterns. Using a multi-state stochastic hotchpotch model, we show here that the mesoscopic behaviour of the non-stirred B--Z reaction is both qualitatively and quantitatively susceptible to the description in terms of stochastic multilevel cellular automata. This further implies that the mesoscopic dynamics of the non-stirred B--Z reaction results from a delicate interplay between a) a maximal number of available states within the elementary time lag (i.e. a minimal time interval needed for demise of a final state) and b) an imprecision or uncertainty in the definition of state. If either the number of time lags is largely different from 7 or the maximal number of available states is smaller than 20,...

  15. A statistical analysis of volatile organic compounds observed during the TEXAQS2000 air quality study at LaPorte, Tx, using proton-transfer-reaction mass spectrometry

    International Nuclear Information System (INIS)

    Statistical analysis of online VOC measurements obtained by proton-transfer-reaction mass spectrometry (PTR-MS) during the TEXAQS2000 intensive period is presented. The experiment was based at the La Porte site, near the Houston ship channel (HSC), and deployed for continuous long-term monitoring. Multivariate techniques helped to identify various VOC sources in the vicinity of HSC and distinguish between different anthropogenic emissions. An assessment is given of the selectivity and interpretation of mass scans from this online technique in complex urban and industrial VOC matrix. (author)

  16. 甲磺酸左氧氟沙星注射液常见不良反应的观察及护理%Observation and nursing of common adverse reaction Levofloxacin Mesylate Injection

    Institute of Scientific and Technical Information of China (English)

    李雪芬

    2013-01-01

    Objective To explore the nursing countermeasures of reducing levofloxacin mesylate for injection adverse reactions . Methods Analysis of the static appearance drops of levofloxacin mesylate injection reaction in clinical observation .Results Levofloxacin mesylate for injection common drip speed and drug adverse reactions and drug related whether fasting .Conclusion Strengthen the nursing period of levofloxacin mesylate injection drug use ,can reduce or avoid its adverse reactions .%目的:探讨减轻甲磺酸左氧氟沙星注射液常见不良反应的护理对策。方法观察分析临床护理工作中静滴甲磺酸左氧氟沙星注射液出现的反应。结果甲磺酸左氧氟沙星注射液常见不良反应与药物的滴速及用药时是否空腹有关。结论加强甲磺酸左氧氟沙星注射液用药期间的护理,可以减少或避免其常见不良反应的发生。

  17. Competition between reaction and intramolecular energy redistribution in solution: observation and nature of nonstatistical dynamics in the ozonolysis of vinyl ethers.

    Science.gov (United States)

    Quijano, Larisa Mae M; Singleton, Daniel A

    2011-09-01

    Experimental product ratios in ozonolyses of alkyl vinyl ethers in solution do not fit with expectations based on statistical rate theories. The selectivity among cleavage pathways increases with the size of the alkyl group but to an extent that is far less than RRKM theory would predict. Trajectory studies account for the observed selectivities and support a mechanism involving a competition between cleavage of the primary ozonide and intramolecular vibrational energy redistribution. A statistical model is presented that assumes that RRKM theory holds for a molecular subset of the primary ozonides, allowing the rates of energy loss from the ozonides to be estimated from the observed product ratios. PMID:21812422

  18. Competition between Reaction and Intramolecular Energy Redistribution in Solution. Observation and Nature of Nonstatistical Dynamics in the Ozonolysis of Vinyl Ethers

    OpenAIRE

    Quijano, Larisa Mae M.; Singleton, Daniel A.

    2011-01-01

    Experimental product ratios in ozonolyses of alkyl vinyl ethers in solution do not fit with expectations from statistical rate theories. The selectivity among cleavage pathways increases with the size of the alkyl group but to an extent that is far less than RRKM theory would predict. Trajectory studies account for the observed selectivities and support a mechanism involving a competition between cleavage of the primary ozonide and intramolecular vibrational energy redistribution. An approxim...

  19. Nuclear Reactions

    OpenAIRE

    Bertulani, C. A.

    2009-01-01

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay of compound nuclei;...

  20. Observation of the Exclusive Reaction e^+e^-\\ to \\phi\\eta at \\sqrt{s}=10.58 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Aubert, B.

    2006-11-17

    The authors report the observation of e{sup +}e{sup -} {yields} {phi}{eta} near {radical}s = 10.58 GeV with 6.5 {sigma} significance in the K{sup +}K{sup -}{gamma}{gamma} final state in a data sample of 224 fb{sup -1} collected by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings. They measure the restricted radiation-corrected cross section to be {sigma}(e{sup +}e{sup -} {yields} {phi}{eta}) = 2.1 {+-} 0.4(stat) {+-} 0.1(syst) fb within the range |cos{theta}*| < 0.8, where {theta}* is the center-of-mass polar angle of the {phi} meson. The {phi} meson is required to be in the invariant mass range of 1.008 < m{sub {phi}} < 1.035 GeV/c{sup 2}. The radiation corrected cross section in the full cos {theta}* range is extrapolated to be 2.9 {+-} 0.5(stat) {+-} 0.1(syst) fb.

  1. Observation of hydrogen absorption/desorption reaction processes in Li-Mg-N-H system by in-situ X-ray diffractmetry

    International Nuclear Information System (INIS)

    The in-situ XRD measurements on dehydrogenation/rehydrogenation of the Li-Mg-N-H system were performed in this work. The ballmilled mixture of 8LiH and 3Mg(NH2)2 as a hydrogenated phase gradually changed into Li2NH as a dehydrogenated phase during heat-treatment at 200 oC in vacuum for 50 h. Neither Mg-related phases nor other intermediate phases were recognized in the dehydrogenated phase. With respect to the hydrogenation process, the dehydrogenated state gradually returned to the mixed phase of the LiH and Mg(NH2)2 without appearance of any intermediate phases during heat treatment at 200 oC under 5 MPa H2 for 37 h and during slow cooling down to room temperature through 24 h. In the hydrogenation process at 200 oC under 1 MPa H2, however, the growing up of the LiNH2 and LiH phase was observed in the XRD profiles before the 3Mg(NH2)2 and 8LiH phases were formed as the final hydrogenated state. This indicates that the LiNH2 and LiH phase essentially appears as an intermediate state in the Li-Mg-N-H system composed of 3Mg(NH2)2 and 8LiH

  2. To observe the intensity of the inflammatory reaction caused by neonatal urine and meconium on the intestinal wall of rats in order to understand etiology of intestinal damage in gastroschisis

    Directory of Open Access Journals (Sweden)

    Devdas S Samala

    2014-01-01

    Full Text Available Objectives: The aim of this experimental study was to observe the intensity of the inflammatory reaction caused by neonatal urine and meconium on the intestinal wall of rats to better understand etiology of intestinal damage in gastroschisis. Materials and Methods: A total of 24 adult Wistar rats were used as experimental models to simulate the effect of exposed bowel in cases of gastroschisis. The peritoneal cavity of the rats was injected with substances which constitute human amniotic fluid to study the effect on the bowel. Sterile urine and meconium were obtained from newborn humans. The rats were divided into four groups according to the material to be injected. In Group I (Control group 3 mL of distilled water was injected, in Group II (Urine group 3 mL of neonatal urine was injected, in Group III (Meconium group 5% meconium suspension was injected, while in Group IV, a combination of 5% meconium suspension and urine was injected. A total of 3mL solution was injected into the right inferior quadrant twice a day for 5 days. The animals were sacrificed on the 6 th day by a high dose of thiopentone sodium. A segment of small bowel specimen was excised, fixed in paraffin, and stained with hematoxylin-eosin for microscopic analysis for determination of the degree of inflammatory reaction in the intestinal wall. All pathology specimens were studied by the same pathologist. Results: The maximum bowel damage was seen in Group II (Urine group in the form of serositis, severe enteritis, parietal necrosis, and peeling. A lesser degree of damage was observed in Group III (Meconium group as mild enteritis (mild lymphoid hyperplasia. The least damage was seen in Group IV (Combination of meconium and urine and Group I (Control group. Conclusion: The intraabdominal injection of neonatal human urine produces significant inflammatory reactions in the intestinal wall of rats.

  3. Clinical observation of physiological and psychological reactions to electric stimulation of the amygdaloid nucleus and the nucleus accumbens in heroin addicts after detoxification

    Institute of Scientific and Technical Information of China (English)

    FANG Jun; GU Jian-wen; YANG Wen-tao; QIN Xue-ying; HU Yong-hua

    2012-01-01

    Background Stereotactic surgery has been used to treat heroin abstinence in China since 2000 by ablating the amygdaloid nucleus (AMY) and the nucleus accumbens (NAc),which also provides opportunity to identify the relationship between these nuclei and addiction.Our study aimed to explore the physiological and psychological effects of electrically stimulating the AMY and the NAc in herein addicts after detoxification by observing changes of heart rate,arterial pressure and occurrence of euphoria similar to heroin induced euphoria.Methods A total of 70 heroin addicts after detoxification were recruited,and 61 of them were eligible to be given stereotactic surgery for heroin abstinence.The operation was carried out after determining the coordinates of all target nucleuses,and stimulation was performed at the AMY and the NAc solely or jointly.Heart rate,arterial pressure and occurrence of euphoria similar to heroin induced euphoria were recorded and analyzed.Results The average heat rate was (66±10) beats/min before electric stimulation,and significantly increased to (84±14) beats/min during stimulation,and changed to (73±12) beats/min 10 minutes after stimulation.There was a significant elevation of the average arterial pressure from 83 mmHg before stimulation to 98 mmHg during the stimulation,and it then decreased to 90 mmHg after stimulation.Forty-three of the 61 patients showed intense euphoria similar to heroin induced euphoria.The largest number (118/186) of euphoric responses occurred when the AMY and the NAc were stimulated at the same time.Odds ratio was 5.4 (95% CI: 2.4-11.9,P <0.0001) to quantify the association.Results from a Logistic regression model showed a positive correlation between unilateral stimulation of either the AMY or NAC and induction of euphoria (OR >1 ),especially when the left AMY or left NAc was stimulated (P <0.05).Conclusions Our data are consistent with existing results that the AMY and the NAc are related to addiction

  4. From the (1B) Spectroscopic State to the Photochemical Product of the Ultrafast Ring-Opening of 1,3-Cyclohexadiene: A Spectral Observation of the Complete Reaction Path.

    Science.gov (United States)

    Pemberton, Christine C; Zhang, Yao; Saita, Kenichiro; Kirrander, Adam; Weber, Peter M

    2015-08-20

    All stages of the electrocyclic ring-opening of 1,3-cyclohexadiene (CHD) were observed by time-resolved photoionization-photoelectron spectroscopy. Spectra of the 1B state, previously unobserved using time-resolved methods, were obtained upon optical excitation using ultrashort laser pulses at 4.60 or 4.65 eV, followed by ionization with pulses at 3.81, 3.85, and 4.10 eV, revealing a 1B lifetime of 30 fs. In an experiment using 3.07 eV probe photons and a 4.69 eV pump, we observed a time-sequenced progression of Rydberg states that includes s, p, and d states of the series n = 3 to 6. The sequentiality of the Rydberg signals points to an ionization mechanism that captures the molecule on different points along the reaction path in 2A. A dynamic fit of the Rydberg signals, coupled with MS-CASPT2 calculations, reveals that as the wavepacket moves down the potential energy surface it acquires kinetic energy at a rate of 28 eV/ps before reaching the conical intersection to the 1A ground state. During the reaction, the terminal carbon atoms separate at a speed of 16 Å/ps. A deconvolution of the Rydberg signals from a broad feature assigned to structurally disperse 1,3,5-hexatriene (HT) shows the formation of the open-chain hexatriene structure with an onset 142 fs after the initial absorption of a pump photon. The experimental observations are discussed in the context of recent ultrafast X-ray scattering experiments and theoretical quantum dynamics simulations. PMID:26192201

  5. Measurement of polarization observables in the reaction {gamma}p{yields} p{pi}{sup 0}{pi}{sup 0} using linearly polarized photons with the CBELSA/TAPS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sokhoyan, Vahe

    2012-07-27

    The spectrum and the properties of baryon resonances can be studied using photons with energies appropriate to excite baryonic states. Double meson photoproduction allows access to cascading resonance decays via other excited states. Also, at higher energies the importance of the double meson photoproduction increases due to higher cross-sections in comparison to single meson photoproduction. To study baryon resonances, the measurement of polarization observables as well as the measurement of differential cross-sections plays a very important role. In this work the three-body polarization observables I{sup s}, I{sup c} and the respective twobody asymmetry {Sigma} were measured for the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0} in an incoming photon energy range of E{sub {gamma}} = 970 - 1650 MeV. The data were acquired with the CBELSA/TAPS experiment located at the ELSA accelerator in Bonn, using a linearly polarized photon beam impinging on a liquid hydrogen target. The observables I{sup s} and I{sup c} which occur in two-meson final states are measured for the first time in the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0}. The corresponding two-body asymmetry {Sigma} is measured in an extended energy range in comparison to already existing data. A comparison with theoretical models shows that the polarization observables provide valuable input to study resonance contributions and their decay modes. The D{sub 33}(1700) {yields} {Delta}{pi} decay is studied based on the comparison of the Bonn-Gatchina Partial Wave Analysis (PWA) predictions with the data. Furthermore, a comparison of the data with the Bonn-Gatchina PWA and the Fix isobar model predictions allows to distinguish between these two models. Additionally, band-like structures and peaks are observed in the mass ranges of {Delta}(1232), D{sub 13}(1520), F{sub 15}(1680), f{sub 0}(980) and f{sub 2}(1270) in the according Dalitz plots and invariant mass distributions. The contributions of these

  6. Observation of the structural changes of sol-gel formed Li2MnTi3O8 during electrochemical reaction by in-situ and ex-situ studies

    International Nuclear Information System (INIS)

    In this work, spinel Li2MnTi3O8 is successfully prepared by using a simple sol-gel route and evaluated as an anode material for lithium-ion batteries. Charge-discharge tests exhibits than spinel Li2MnTi3O8 can deliver an initial discharge capacity of 273.5 mAh g−1 and the reversible capacity is kept at 206.1 mAh g−1 after 50 cycles, corresponding to 94.5% of the initial charge capacity. The electrochemical reaction mechanism between Li2MnTi3O8 and lithium is investigated based on the results of various in-situ and ex-situ observations. The result indicates that the (Li0.505Mn0.495)tet(Li0.495Mn0.005)octTi1.5octO4 has multiple interstitials to accommodate lithium ions during the lithiation process, in which the octahedral sites (4a) would be occupied by lithium ions at high working potential and the tetrahedral sites (8c) would be occupied by lithium ions at low working potential. As a result, two two-phase transitions between three end-number phases Li2MnTi3O8, Li3MnTi3O8 and Li5MnTi3O8 can be observed during the reversible electrochemical reaction between Li2MnTi3O8 and lithium

  7. RILEM TC ISR Summer 2015 Activity Report

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, Yann [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    With aging infrastructures, instances of Alkali Silica Reaction (ASR) and Delayed Ettringite Formation (DEF), broadly covered under the term Internal Swelling Reaction (ISR), are increasingly being detected. They have been observed in bridges, dams, and most recently in nuclear power plants. Concrete swelling may result in bridge partial failure, dams with structural cracks and misaligned turbine shafts, and locked slice gates. For nuclear reactors micro-cracks may cause increased gas permeability which will jeopardize the containment integrity and may decrease the residual structural resistance under accidental loading. This TC, which limits its activity to structures with known expansive concrete, seeks to address two complementary but fundamental questions: a) What is the kinetics of the reaction and b) How would it affect the integrity of the structure (serviceability and strength) and thus establish a science based prognostic to the structure owner.

  8. Reactions of oriented molecules.

    Science.gov (United States)

    Brooks, P R

    1976-07-01

    Beams of oriented molecules have been used to directly study geometrical requirements in chemical reactions. These studies have shown that reactivity is much greater in some orientations than others and demonstrated the existence of steric effects. For some reactions portions of the orientation results are in good accord with traditional views of steric hindrance, but for others it is clear that our chemical intuition needs recalibrating. Indeed, the information gained from simultaneously orienting the reactants and observing the scattering angle of the products may lead to new insights about the detailed mechanism of certain reactions. Further work must be done to extend the scope and detail of the studies described here. More detailed information is needed on the CH(3)I reaction and the CF(3)I reaction. The effects of alkyl groups of various sizes and alkali metals of various sizes are of interest. In addition, reactions where a long-lived complex is formed should be studied to see if orientation is important. Finally, it would be of interest to apply the technique to the sort of reactions that led to our interest in the first place: the S(N)2 displacements in alkyl halides where the fascinating Walden inversion occurs. PMID:17793988

  9. Reaction mechanisms

    International Nuclear Information System (INIS)

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported

  10. Structural modelling of ASR-affected concrete: The approach developed in the PAT-ASR project

    NARCIS (Netherlands)

    Esposito, R.; Hendriks, M.A.N.

    2013-01-01

    The Alkali-Silica Reaction is a harmful reaction which can compromise the integrity and capacity of concrete structures. Due to its nature, a multiscale material model has been chosen to perform structural analyses. The model aims to couple the chemical and mechanical effects in order to characteriz

  11. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2011-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...... as the idea of the naïve observer becomes a void. Not recognizing and observing oneself as observer and co-producer of empirical data simply leaves the process of observation as the major unobserved absorber of contingency in data production based on participating observation....

  12. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2010-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...... as the idea of the naïve observer becomes a void. Not recognizing and observing oneself as observer and co-producer of empirical data simply leaves the process of observation as the major unobserved absorber of contingency in data production based on participating observation....

  13. Electrochemical reactions and ionization processes

    OpenAIRE

    Girault, Hubert; Liu, Baohong; Qiao, Liang; Bi, Hongyan; Prudent, Michel; Lion, Niels; Abonnenc, Mélanie

    2010-01-01

    Electrochemical or photo-electrochemical reactions in both electrospray ionization and laser desorption ionization are discussed stressing the role of the electrode reaction in influencing the ionization process. In particular, upon application of a high voltage during electrospray ionization, the emitter includes a working electrode, where redox reactions are observed, such as electro-generation of benzoquinone and metal ions. In contrast, the target plate in laser-induced desorption ionizat...

  14. Nuclear reactions and structure

    International Nuclear Information System (INIS)

    A more complete data base for deriving level parameters for specific nuclei is provided by using charged-particle induced reactions. (α,pγ) reactions on 40Ca, 52Cr, 19F, 26Mg, 48Ti and 51V at Eα = 12 MeV have been used to excite levels in 43Sc, 55Mn, 22Ne, 29Al, 51V and 54Cr. Gamma rays were observed in coincidence with associated protons using a multiparameter data acquisition system. 5 figs., 9 refs., 1 tab

  15. Nuclear structure, nuclear reaction

    OpenAIRE

    Etchegoyen, Maria Cristina Berisso de.; Sinclair, D.; Dr. D. Sinclair

    1982-01-01

    In this thesis, particle- particle angular correlations for reactions in non-zero degree geometry and with non-zero spin nuclei are performed and found to be a valuable tool for spin determination, (d-α) angular correlations in the reaction process 14N(6Li,d)18F* (α)14N are measured for three high excited states in 18F with a 6Li beam of 36MeV. Spins and parities for two of the observed states are determined, and in agreement with theoretical predictions, these states are s...

  16. Adverse reactions to radiopharmaceuticals

    International Nuclear Information System (INIS)

    Full text. An adverse reaction can occur following administration of a radio pharmaceutical, but fortunately reactions are uncommon. They are usually mild and do not require intensive treatment. This is probably related to the fact that only small chemical quantities of material are administered to patients and that only one or a small number of doses are administered. Since symptoms are unrelated to any known pharmacology of the agents, they can be described as Type B reactions according to the classification of Rawlings and Thompson. Types of reaction that occur and possible mechanisms will be described. The reactions most commonly observed are skin rashes and vasomotor symptoms. It is important that, as far as possible, a cause - effect relationship can be established between the administration of the radio pharmaceutical and the symptoms caused. Some classification schemes therefore exclude vasomotor reactions such as hypotension and slow pulse, since such events can arise in a variety of clinical situations unrelated to radio pharmaceutical administration. It is important for nuclear medicine departments to be aware of the nature of reactions such that they can be recognized and appropriate re-assurance and/or prompt treatment can be given to their patients. Radio pharmaceuticals most frequently mentioned in reporting schemes are di phosphonates used for bone imaging. This probably reflect the fact that these agents are the most frequently used in current practice rather than that they cause more reactions. Problems in establishing the overall frequency of adverse reactions to radio pharmaceuticals include the fact that events may not be recognized if they occur after the patient has left the Nuclear Medicine Department and that reactions are never reported. Two recent studies have attempted to obtain more definitive information by performing prospective studies in a large number of departments. A study in the USA found that there was a rate of 2.3 events per

  17. Selective alpha particle decay of /sup 12/C + /sup 12/C resonances to excited /sup 20/Ne rotational bands observed in the /sup 12/C(/sup 12/C,. cap alpha. ) /sup 20/Ne reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, R.J.; Ordonez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.

    1984-09-01

    Excitation functions of the /sup 12/C(/sup 12/C, ..cap alpha..)/sup 20/Ne reaction were measured at Theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14-40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.

  18. Selective alpha particle decay of /sup 12/C+ /sup 12/C resonances to excited /sup 20/Ne rotational bands observed in the /sup 12/C(/sup 12/C,. cap alpha. ) /sup 20/Ne reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ledoux, R.J.; Ordoez, C.E.; Bechara, M.J.; Al-Juwair, H.A.; Lavelle, G.; Cosman, E.R.

    1984-09-01

    Excitation functions of the /sup 12/C(/sup 12/C,..cap alpha..) /sup 20/Ne reaction were measured at theta/sub lab/ = 7.5/sup 0/ between E/sub c.m./ = 14--40 MeV and angular distributions were measured from E/sub c.m./ = 17.8 to 20.6 MeV. Summed yields reveal prominent intermediate structure resonances over the entire range which correlate well to resonances previously observed in elastic data. The resonances show enhanced decays to excited rotational bands in /sup 20/Ne with reduced widths comparable to those for the elastic channel and an order of magnitude greater than those for the /sup 20/Ne ground state band. A discussion is given of the resonances as shape-isomeric states in a shell model secondary minimum in /sup 24/Mg, and of the selective alpha decay as being transitions to states of related configuration in /sup 20/Ne.

  19. A multiscale theoretical methodology for the calculation of electrochemical observables from ab initio data: Application to the oxygen reduction reaction in a Pt(1 1 1)-based polymer electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    In this work we present a multiscale theoretical methodology that scales up ab initio calculated data into elementary kinetic models in order to simulate Polymer Electrolyte Membrane Fuel Cells (PEMFC) transient operation. Detailed Density Functional Theory (DFT) calculations are performed on a model Pt(1 1 1) surface to determine the elementary kinetic rates of the Oxygen Reduction Reaction (ORR) mechanism at a Pt-based PEMFC cathode. These parameters include the effect of surface coverage on the activation barriers and are implemented into a Mean Field model describing the behavior of the electric field and charge distribution at the nanoscale interfacial vicinity to the catalyst, which is in turn coupled with microscale and mesoscale level models describing the charge and reactants and water transport phenomena across the cell. The impact of two possible ORR mechanisms on the simulated i–V curves is investigated: a first route connected with the dissociative adsorption of molecular oxygen on Pt(1 1 1), a second route related to the formation and the transformation of OOH surface species. The similarities and differences of the associated calculated i–V responses for each of these routes and the consequences on the interpretation of electrochemical observables at the cell level are discussed.

  20. Nuclear reactions

    International Nuclear Information System (INIS)

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

  1. Observation of nursing and influence by esmolol on tracheal intubation cardiovascular reaction%艾司洛尔对气管插管心血管反应的影响及护理观察

    Institute of Scientific and Technical Information of China (English)

    陈美珠; 许惠春

    2016-01-01

    ObjectiveTo evaluate preventive effect by esmolol for tracheal intubation cardiovascular reaction.MethodsA total of 80 ASA grade Ⅰ~Ⅱ patients receiving gynecological laparoscopic operation under general anesthesia were randomly divided into control group (group C) and esmolol group (group E), with 40 cases in each group. They received respectively 5 ml normal saline and 5 ml (1 mg/kg) esmolol in 3 min before tracheal intubation through intravenous injection. Observation was made on changes of mean arterial pressure (MAP) and heart rate (HR) in 1, 3, 5 min after intubation.ResultsIn 1 and 3 min after tracheal intubation, group E had all lower MAP and HR than group C, and their difference had statistical significance (P<0.05). ConclusionIntravenous injection of esmolol by 1 mg/kg in 3 min before tracheal intubation can remarkably reduce tracheal intubation cardiovascular reaction, and it is helpful for nursing in tracheal intubation.%目的:评估艾司洛尔对气管插管心血管反应的预防作用。方法80例ASA Ⅰ~Ⅱ级、全身麻醉下行妇科腹腔镜手术患者,随机分为对照组(C组)和艾司洛尔组(E组),每组40例,分别于气管插管前3 min缓慢静脉推注生理盐水5 ml和艾司洛尔5 ml(1 mg/kg),观察插管后1、3、5 min的平均动脉压(MAP)、心率(HR)变化。结果气管插管后1、3 min E组 MAP和HR 均显著低于C组,差异有统计学意义(P<0.05)。结论气管插管前3 min缓慢静脉推注艾司洛尔1 mg/kg,显著减轻了气管插管的心血管反应,有利于气管插管的护理。

  2. Polarization phenomena in collinear reactions

    Science.gov (United States)

    Moravcsik, Michael J.; Arash, Firooz

    1985-06-01

    It is shown for a collinear reaction containing four particles with arbitrary spins which amplitudes remain nonzero and how they are related to the observables. In terms of primary observables all submatrices relating products of amplitudes to observables either vanish or turn into one-by-one submatrices, except the 8i types which may turn into three-by-three submatrices, but these latter submatrices are mostly avoidable when determining amplitudes. In terms of the secondary observables the 1M and 2i submatrices are slightly larger. Specifically, it is shown that in collinear reactions all observables in which only one particle is polarized (no matter how) vanish. Since reactions at very high energies are expected to be predominantly very close to being collinear, the smallness of such observables in such reactions can be expected on general grounds but polarization effects involving observables with more than one polarized particle can very well be very large. An iterative approximation method for the polarization analysis of reactions at very high energies is suggested. The results of this paper are also applicable to all models in which helicity conservation holds, since they are, for all t values, formally identical with collinear reactions.

  3. Polarization phenomena in collinear reactions

    International Nuclear Information System (INIS)

    It is shown for a collinear reaction containing four particles with arbitrary spins which amplitudes remain nonzero and how they are related to the observables. In terms of primary observables all submatrices relating products of amplitudes to observables either vanish or turn into one-by-one submatrices, except the 8/sub i/ types which may turn into three-by-three submatrices, but these latter submatrices are mostly avoidable when determining amplitudes. In terms of the secondary observables the 1/sub M/ and 2/sub i/ submatrices are slightly larger. Specifically, it is shown that in collinear reactions all observables in which only one particle is polarized (no matter how) vanish. Since reactions at very high energies are expected to be predominantly very close to being collinear, the smallness of such observables in such reactions can be expected on general grounds but polarization effects involving observables with more than one polarized particle can very well be very large. An iterative approximation method for the polarization analysis of reactions at very high energies is suggested. The results of this paper are also applicable to all models in which helicity conservation holds, since they are, for all t values, formally identical with collinear reactions

  4. Cellular basis of the immunohematologic defects observed in short-term semiallogeneic B6C3F1→C3H chimeras: evidence for host-versus-graft reaction initiated by radioresistant T cells

    International Nuclear Information System (INIS)

    Lethally irradiated C3Hf mice reconstituted with a relatively low dose (2 x 106) of B6C3F1 bone marrow cells (B6C3F1→C3Hf chimeras) frequently manifest immunohematologic deficiencies during the first month following injection of bone marrow cells. They show slow recovery of antibody-forming potential to sheep red blood cells (SRBC) as compared to that observed in syngeneic (C3Hf→C3Hf or B6C3F1→B6C3F1) chimeras. They also show a deficiency of B-cell activity as assessed by antibody response to SRBC following further reconstitution with B6C3F1-derived thymus cells 1 week after injection of bone marrow cells. A significant fraction of B6C3F1→C3Hf chimeras was shown to manifest a sudden loss of cellularity of spleens during the second week following injection of bone marrow cells even though cellularity was restored to the normal level within 1 week. The splenic mononuclear cells recovered from such chimeras almost invariably showed strong cytotoxicity against target cells expressing donor-type specific H-2 antigens (H-2/sup b/) when assesed by 51Cr-release assay in vitro. The effector cells responsible for the observed anti-donor specific cytotoxicity were shown to be residual host-derived T cells. These results indicate strongly that residual host T cells could develop anti-donor specific cytotoxicity even after exposure to a supralethal dose (1050 R) of radiation and that the immunohematologic disturbances observed in shortterm F1 to parent bone marrow chimeras (B6C3F1→C3Hf) were due to host-versus-graft reaction (HVGR) initiated by residual host T cells. The implication of these findings on the radiobiological nature of the residual T cells and the persistence of potentially anti-donor reactive T-cell clones in long-surviving allogeneic bone marrow chimeras was discussed

  5. Bulk Nuclear Properties from Reactions

    OpenAIRE

    Danielewicz, P.

    2002-01-01

    Extraction of bulk nuclear properties by comparing reaction observables to results from semiclassical transport-model simulations is discussed. Specific properties include the nuclear viscosity, incompressibility and constraints on the nuclear pressure at supranormal densities.

  6. Electrochemical Chloride extraction using external electrodes?

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Pedersen, Anne Juul

    cathode. However, some unwanted side effects can occur, including alkali-silica reaction and in some cases hydrogen embrittlement. It is also suggested also to use electrochemical chloride extraction in a preventive way in constructions where chloride induced corrosion is likely to be a problem after a...

  7. The Glaser–Hay reaction

    DEFF Research Database (Denmark)

    Vilhelmsen, Mie Højer; Jensen, Jonas; Tortzen, Christian;

    2013-01-01

    The oxidative Glaser–Hay coupling of two terminal alkynes to furnish a butadiyne is a key reaction for acetylenic scaffolding. Although the reaction is performed under rather simple conditions [CuCl/TMEDA/O2 (air)], the mechanism is still under debate. Herein we present detailed studies on the...... scope of this reaction by using both 13C NMR and UV/Vis spectroscopic methods. The former method was used to study the kinetics of the coupling of aryl-substituted alkynes as the aryl carbon resonances of the reactants and products have similar NOEs and relaxation times. The reaction was found to be...... zero-order with respect to the terminal alkyne reactant under standard preparative conditions. Moreover, as the reaction proceeded, a clear change to slower reaction kinetics was observed, but it was still apparently zero-order. The onset of this change was found to depend on the catalyst loading. This...

  8. 养肺消疹汤治疗EGFR-TKIs药物相关不良皮肤反应的临床观察%Clinical observation on treatment of EGFR-TKIs-related adverse skin reactions with Yangfei Xiaozhen Tang

    Institute of Scientific and Technical Information of China (English)

    孙韬; 杨婕; 胡凯文

    2013-01-01

    Objective To observe the curative effect of Yangfei Xiaozhen Tang on EGFR-TKIs-related adverse skin reactions. Methods The patients (n=50) with non-small-cell lung cancer (NSCLC) and rash after taking EGFR-TKIs were randomly divided into two groups and respectively treated with Yangfei Xiaozhen Tang used orally combining washing (treatment group, n=25) and external pimecrolimus ointment (control group, n=25). The changes of rash grading, TCM syndromes and relief of quality of life (QOL) were observed in two groups. Results In treatment group, the rash grading was improved at all time points. After treatment for 30 days, the effective rate was 72%in treatment group and 44%in control group. The recovery rate of TCM syndromes was 92%in treatment group and 36%in control group after treatment. The scores of QOL were superior in treatment group after treatment for 14 days and 30 days. Conclusion Yangfei Xiaozhen Tang used orally combining washing has good curative effect on EGFR-TKIs-related adverse skin reactions.%目的:观察养肺消疹汤治疗表皮生长因子受体酪氨酸激酶抑制剂(EGFR-TKIs)药物相关不良皮肤反应的疗效。方法将50例服用EGFR-TKIs后出现皮疹的非小细胞肺癌患者随机分为2组各25例,治疗组采用养肺消疹汤口服联合外洗进行治疗,对照组采用吡美莫司软膏外用的方法进行治疗,观察各组皮疹分级、中医证候、生活质量改善情况。结果治疗组在各个检测时点皮疹分级均有显著改善,且优于对照组;治疗30 d后治疗组、对照组皮疹治疗有效率分别为72%与44%;治疗前后治疗组与对照组中医证候改善率分别为92%与36%;治疗14,30 d后2组生活质量评分治疗组有显著优势。结论养肺消疹汤口服联合外洗对EGFR-TKIs药物相关不良皮肤反应具有良好疗效。

  9. A new study of the {sup 22}Ne(p, γ){sup 23}Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cavanna, F.; Corvisiero, P.; Ferraro, F.; Prati, P. [Universita di Genova, Dipartimento di Fisica, Genova (Italy); INFN, Sezione di Genova (Italy); Depalo, R. [INFN, Sezione di Padova, Padova (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Menzel, M.L.; Anders, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Technische Universitaet Dresden, Dresden (Germany); Aliotta, M.; Bruno, C.G.; Davinson, T.; Scott, D.A. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Bemmerer, D.; Szuecs, T. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Broggini, C.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Caciolli, A. [INFN, Sezione di Padova, Padova (Italy); Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Di Leva, A.; Imbriani, G. [Universita degli Studi di Napoli Federico II, Dipartimento di Fisica, Napoli (Italy); INFN, Sezione di Napoli (Italy); Elekes, Z.; Fueloep, Z.; Gyuerky, G.; Somorjai, E. [Institute of Nuclear Research of the Hungarian Academy of Sciences (MTA ATOMKI), Debrecen (Hungary); Formicola, A.; Junker, M. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gervino, G. [Universita di Torino, Dipartimento di Fisica Sperimentale, Torino (Italy); INFN, Sezione di Torino (Italy); Guglielmetti, A.; Trezzi, D. [Universita degli Studi di Milano, and INFN, Sezione di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [Osservatorio Astronomico di Collurania, Teramo (Italy); Ruhr-Universitaet Bochum, Bochum (Germany); Strieder, F. [Ruhr-Universitaet Bochum, Bochum (Germany); Collaboration: LUNA Collaboration

    2014-11-15

    The {sup 22}Ne(p,γ){sup 23}Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle is active in asymptotic giant branch stars as well as in novae and contributes to the nucleosythesis of neon and sodium isotopes. In order to reduce the uncertainties in the predicted nucleosynthesis yields, new experimental efforts to measure the {sup 22}Ne(p,γ){sup 23}Na cross section directly at the astrophysically relevant energies are needed. In the present work, a feasibility study for a {sup 22}Ne(p,γ){sup 23}Na experiment at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator deep underground in the Gran Sasso laboratory, Italy, is reported. The ion-beam-induced γ-ray background has been studied. The feasibility study led to the first observation of the E{sub p}=186 keV resonance in a direct experiment. An experimental lower limit of 0.12 x 10{sup -6} eV has been obtained for the resonance strength. Informed by the feasibility study, a dedicated experimental setup for the {sup 22}Ne(p,γ){sup 23}Na experiment has been developed. The new setup has been characterized by a study of the temperature and pressure profiles. The beam heating effect that reduces the effective neon gas density due to the heating by the incident proton beam has been studied using the resonance scan technique, and the size of this effect has been determined for a neon gas target. (orig.)

  10. Post-marketing surveillance of the safety profile of iodixanol in the outpatient CT setting. A prospective, multicenter, observational study of patient risk factors, adverse reactions and preventive measures in 9953 patients

    International Nuclear Information System (INIS)

    Non-interventional study in outpatient, contrast-enhanced CT: 1. to determine the extent of preventive measures for risk reduction of adverse drug reactions after contrast-enhanced CT examinations. 2. to prospectively determine the incidence and severity of adverse drug reactions occurring after administration of the iso-osmolar contrast medium iodixanol. 3. to determine a possible influence of preventive measures on the incidence/severity of adverse drug reactions. Evaluable documentation was provided for 9953 patients from 66 radiology centers across Germany. Patient characteristics, aspects of iodixanol administration, and adverse events with an at least 'possible' relationship were documented on a standardized case report form (CRF) and were evaluated up to seven days after contrast medium administration. About 55.5% of patients showed one or more risk factors (e.g. impaired renal function 4.4%, diabetes mellitus 8.5%, hypertension 20.6%). One third of the sites did not implement any preventive measures. Patients with a known risk for an allergy-like reaction were more likely to receive pharmacologic preventive treatment (0.5-50.5%). Oral hydration was the main preventive measure in patients with renal risk factors (<8%) followed by intravenous hydration (1%). Adverse drug reactions, mainly hypersensitivity reactions, occurred in 77 patients (0.74%), but were classified as serious in only 3 patients (0.03%). No statistically significant correlation between risk factors, preventive measures, and adverse reactions could be found. The use of preventive measures for CT examinations in this outpatient setting was generally low with risk patients being pre-medicated more often, depending on their history. In the routine outpatient setting, iso-osmolar iodixanol was very well tolerated in almost 10 000 patients undergoing diagnostic CT. The rate of acute and delayed adverse reactions was low. No correlation could be found between risk factors, preventive measures and

  11. Post-marketing surveillance of the safety profile of iodixanol in the outpatient CT setting. A prospective, multicenter, observational study of patient risk factors, adverse reactions and preventive measures in 9953 patients

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Frank Hugo Heinz [Radiology and Nuclear Medicine Center, Ludwigshafen (Germany)

    2014-11-15

    Non-interventional study in outpatient, contrast-enhanced CT: 1. to determine the extent of preventive measures for risk reduction of adverse drug reactions after contrast-enhanced CT examinations. 2. to prospectively determine the incidence and severity of adverse drug reactions occurring after administration of the iso-osmolar contrast medium iodixanol. 3. to determine a possible influence of preventive measures on the incidence/severity of adverse drug reactions. Evaluable documentation was provided for 9953 patients from 66 radiology centers across Germany. Patient characteristics, aspects of iodixanol administration, and adverse events with an at least 'possible' relationship were documented on a standardized case report form (CRF) and were evaluated up to seven days after contrast medium administration. About 55.5% of patients showed one or more risk factors (e.g. impaired renal function 4.4%, diabetes mellitus 8.5%, hypertension 20.6%). One third of the sites did not implement any preventive measures. Patients with a known risk for an allergy-like reaction were more likely to receive pharmacologic preventive treatment (0.5-50.5%). Oral hydration was the main preventive measure in patients with renal risk factors (<8%) followed by intravenous hydration (1%). Adverse drug reactions, mainly hypersensitivity reactions, occurred in 77 patients (0.74%), but were classified as serious in only 3 patients (0.03%). No statistically significant correlation between risk factors, preventive measures, and adverse reactions could be found. The use of preventive measures for CT examinations in this outpatient setting was generally low with risk patients being pre-medicated more often, depending on their history. In the routine outpatient setting, iso-osmolar iodixanol was very well tolerated in almost 10 000 patients undergoing diagnostic CT. The rate of acute and delayed adverse reactions was low. No correlation could be found between risk factors, preventive

  12. Dechlorinating reaction of organic chlorides

    International Nuclear Information System (INIS)

    Dechlorination has been examined by the reaction between iron, aluminum powder or CaO and organic chlorides such as C2HCl3 and CH2Cl2. Progress of the reaction was analyzed with mass spectrometer. The reaction between iron and organic chloride was rapidly occurred at the temperature between 350 and 440degC in an atmosphere of argon. Above 380degC, more than 99.5% of C2HCl3 was decomposed within approximately 100 minutes. At 440degC, approximately 60% of C2HCl3 was decomposed by the reaction with aluminium powder within approximately 100 minutes. At 440degC, reaction between C2HCl3 and CaO powder were occurred rapidly in an atmosphere of argon to form CaCl2 and free carbon. Also in an atmosphere of air, nearly the same result was obtained. In this reaction, CaCl2, CO and CO2 were formed. CH2Cl2 was also decomposed by the reaction with iron at the temperature between 380 and 440degC. In the reaction, FeCl2, carbon and hydrogen were formed. CH3+ and CH4 were observed during the dechlorinating reaction of CH2Cl2. Variation in particle size of iron powder such as 100, 150 and 250 mesh did not affect the reaction rate. (author)

  13. Chain reaction

    International Nuclear Information System (INIS)

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  14. Permutation properties of observables

    International Nuclear Information System (INIS)

    Relations which characterize the permutation properties of the polarization observables in nuclear reactions are derived. It is shown that the permutation symmetry of the observables in reactions with identical particles in one of the channels is independent of the reaction mechanism. The angular dependence of the vector analyzing power of the reaction d+d→p+t is studied in a model-free manner. It is proved that, contrary to conclusions reached by some authors, the angular-momentum constraints imposed by the direct mechanisms are insufficient for violating the permutation-symmetry properties. It is shown that if the reaction d+d→p+t at a few tens of MeV of energy proceeds via a pure direct mechanism (usually considered as transfer of a nucleon with l = 0) then the character of its vector analyzing power gives evidence for contributions from the l = 2 transitions

  15. Permutation properties of observables

    International Nuclear Information System (INIS)

    Relations are derived which characterize the permutation properties of the polarization observables in nuclear reactions. It is shown that the permutation symmetry of the observables in reactions with identical particles in one of the channels is independent of the reaction mechanism. The angular dependence of the vector analysing power of the reaction d+d→p+t is studied in a model-free manner. It is prooved that contrary to conclusions made by some authors, the angular momentum constrains imposed by the direct mechanism are insufficient for violating the permutation properties. It is shown that if the reaction d+d→p+t at few tens MeV energy proceeds via a pure direct mechanism (usually considered as l=0 nucleon transfer), then the character of its vector analysing power gives evidence for the contribution from l=2 transitions

  16. Multinucleon transfer reactions

    International Nuclear Information System (INIS)

    Nuclear reactions induced by complex nuclei are studied. The description of the single neutron transfer is used to show some aspect of the theoretical treatment of transfer reactions and rules concerning the dependence of cross sections on quantum numbers of the initial and final channels are deduced. Strongly excited states of 20Ne, 19F, sup(16,17)0, 15N were studied experimentally by using different projectile-target combinations in the four-particle, eight-particle and ten-particle transfer reactions, leading to the some final nuclei. Obtained results are discussed. In addition, studies of the projectile break-up phenomenon were performed. The dissociation of 6Li and 7Li projectiles was investigated in reactions on Pb, Sn and Ni nuclei. These nuclei were chosen to allow measurements at one incident energy below, above and at the Coulomb barrier. The observed spectra indicate that the process proceeds primarily via the resonance level but the shape deviates from the shape which was calculated assuming isotropic decay of the excited 6Li in its center of mass system. The investigations of the elastic scattering turned out to be more fruitful and allowed to define better the Coulomb barrier for the 6Li-target system. (S.B.)

  17. Azlactone Reaction Developments.

    Science.gov (United States)

    de Castro, Pedro P; Carpanez, Arthur G; Amarante, Giovanni W

    2016-07-18

    Azlactones (also known as oxazolones) are heterocycles usually employed in the stereoselective synthesis of α,α-amino acids, heterocycles and natural products. The versatility of the azlactone scaffold arises from the numerous reactive sites, allowing its application in a diversity of transformations. This review aims to cover classical and recent applications of oxazolones, especially those involving stereoselective processes. After a short introduction on their structures and intrinsic reactivities, dynamic kinetic resolution (DKR) processes as well as reactions involving stereoselective formation of a new σ C-C bond, such as alkylation/allylation/arylation, aldol, ene, Michael and Mannich reactions will be exposed. Additionally, cycloadditions, Steglich rearrangement and sulfenylation reactions will also be discussed. Recent developments of the well-known Erlenmeyer azlactones will be described. For the most examples, the proposed mechanism, activation modes and/or key reaction intermediates will be exposed to rationalize both the final product and the observed stereochemistry. Finally, this review gives an overview of the synthetic utility of oxazolones. PMID:27245128

  18. Cluster knockout reactions

    Indian Academy of Sciences (India)

    Arun K Jain; B N Joshi

    2014-04-01

    Cluster knockout reactions are expected to reveal the amount of clustering (such as that of , d and even of heavier clusters such as 12C, 16O etc.) in the target nucleus. In simple terms, incident medium high-energy nuclear projectile interacts strongly with the cluster (present in the target nucleus) as if it were existing as a free entity. Theoretically, the relatively softer interactions of the two outgoing particles with the residual nucleus lead to optical distortions and are treated in terms of distorted wave (DW) formalism. The long-range projectile–cluster interaction is accounted for, in terms of the finite range (FR) direct reaction formalism, as against the more commonly adopted zero-range (ZR) distorted wave impulse approximation (DWIA) formalism. Comparison of the DWIA calculations with the observed data provide information about the momentum distribution and the clustering spectroscopic factor of the target nucleus. Interesting results and some recent advancements in the area of (, 2) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out.

  19. EXERCISE AND REACTION TIMES

    Directory of Open Access Journals (Sweden)

    Varun

    2015-03-01

    Full Text Available OBJECTIVES: Physical exercise provides multiple benefits to an individual. It is known that exercising regularly can prevent coronary heart disease, hypertension and obesity and improve flexibility. The effect of exercise on visual reaction time needs to be studied, a s the existing data on the benefit of aerobic exercise on psychomotor functions is insufficient. MATERIALS AND METHODS: Online Visual reaction time is measured before and after exercise. Subjects were instructed to run on the spot with a springy step in ex aggerated motion for 50 to 60 counts at 2 counts per second, maintaining a constant rhythm. RESULTS: We observed that reaction time was significantly lower after performance of exercise. Individuals reported improved mental alertness, feel good factor, bet ter mood and increase circulation. CONCLUSION: Improving reaction times in sports can help the athlete to optimize his performance in making decisions and increasing attention span for example getting off the starting blocks sooner or successfully making c ontact with the ball. In addition this study shows that use of physical exercise helps improve cognitive function. Exercise proves to be a cheap non pharmacological alternative to improve cognitive performance.

  20. Conceptual model for concrete long time degradation in a deep nuclear waste repository

    Energy Technology Data Exchange (ETDEWEB)

    Lagerblad, B.; Traegaardh, J. [Swedish Cement and Concrete Research Inst., Stockholm (Sweden)

    1994-02-01

    This report is mainly a state-of-the-art report of concrete long time durability in the environment expected in a deep site underground nuclear waste repository in Swedish crystalline bedrock. The report treats how the concrete and the surrounding groundwater will interact and how they will be affected by cement chemistry, type of aggregate etc. The different mechanisms for concrete alteration treated include sulphate attack, carbonation, chloride attack, alkali-silica reaction and leaching phenomena. In a long time perspective, the chemical alterations in concrete is mainly governed by the surrounding groundwater composition. After closure the composition of the groundwater will change character from a modified meteoric to a saline composition. Therefore two different simulated groundwater compositions have been used in modelling the chemical interaction between concrete and groundwater. The report also includes a study of old and historical concrete which show observations concerning recrystallization phenomena in concrete. 72 refs, 39 figs.

  1. Conceptual model for concrete long time degradation in a deep nuclear waste repository

    International Nuclear Information System (INIS)

    This report is mainly a state-of-the-art report of concrete long time durability in the environment expected in a deep site underground nuclear waste repository in Swedish crystalline bedrock. The report treats how the concrete and the surrounding groundwater will interact and how they will be affected by cement chemistry, type of aggregate etc. The different mechanisms for concrete alteration treated include sulphate attack, carbonation, chloride attack, alkali-silica reaction and leaching phenomena. In a long time perspective, the chemical alterations in concrete is mainly governed by the surrounding groundwater composition. After closure the composition of the groundwater will change character from a modified meteoric to a saline composition. Therefore two different simulated groundwater compositions have been used in modelling the chemical interaction between concrete and groundwater. The report also includes a study of old and historical concrete which show observations concerning recrystallization phenomena in concrete. 72 refs, 39 figs

  2. On Reaction Coordinate Optimality.

    Science.gov (United States)

    Krivov, Sergei V

    2013-01-01

    The following question is addressed: how to establish that a constructed reaction coordinate is optimal, i.e., that it provides an accurate description of dynamics. It is shown that the reaction coordinate is optimal if its cut free energy profile, determined using length-weighted transitions, is constant, i.e., it is position and sampling interval independent. The observation leads to a number of interesting results. In particular, the equilibrium flux between two boundary states can be computed exactly as diffusion on a free energy profile associated with the coordinate. The mean square displacement, for the trajectory projected onto the coordinate, grows linear with time. That for the same trajectory projected onto a suboptimal coordinate grows slower than linear with time. The results are illustrated on a number of model systems, Sierpinski gasket, FIP35 protein, and beta3s peptide. PMID:26589017

  3. Observation and nursing experience of adverse reactions of children vaccinated with chicken pox vaccine%儿童接种水痘疫苗的不良反应观察及护理体会

    Institute of Scientific and Technical Information of China (English)

    李晓琴

    2015-01-01

    objective: to investigate the children chickenpox vaccine adverse reactions and the nursing countermeasures. Methods: retrospectiveanalysis of 226 cases of children had chickenpox vaccine in our adverse reactions and the nursing measures. Results: all children within a few hours after inoculation, there are different degree of mild fever, swelling pain, mild skin rashes, mild chicken pox adverse reaction, nursing measures, reduce the adverse reaction. Conclusion: the adverse reactions of vaccinated children appear in the corresponding nursing measures, can effectively reduce the occurrence of adverse reactions, and improve the success rate of the vaccination is chickenpox vaccine ascending children's health.%目的:探讨儿童接种水痘疫苗的不良反应及护理对策.方法:回顾分析我院已经接种水痘疫苗的儿童226例的不良反应及护理措施.结果:所有儿童在接种结束后的几小时内,出现有不同程度上的轻微发热、局部红肿疼痛、轻微皮疹、轻度水痘不良反应,采取护理措施后,不良反应减少.结论:针对接种后的儿童出现的不良反应进行相应的护理措施,能够有效的减少不良反应的发生,提高接种是水痘疫苗的成功率,提升儿童的身体健康.

  4. On thermonuclear reaction rates

    OpenAIRE

    Hans J. Haubold; Mathai, Arak Mathai

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  5. Fluctuations in catalytic surface reactions

    CERN Document Server

    Imbihl, R

    2003-01-01

    The internal reaction-induced fluctuations which occur in catalytic CO oxidation on a Pt field emitter tip have been studied using field electron microscopy (FEM) as a spatially resolving method. The structurally heterogeneous Pt tip consists of facets of different orientations with nanoscale dimensions. The FEM resolution of roughly 2 nm corresponds to a few hundred reacting adsorbed particles whose variations in the density are imaged as brightness fluctuations. In the bistable range of the reaction one finds fluctuation-induced transitions between the two stable branches of the reaction kinetics. The fluctuations exhibit a behaviour similar to that of an equilibrium phase transition, i.e. the amplitude diverges upon approaching the bifurcation point terminating the bistable range of the reaction. Simulations with a hybrid Monte Carlo/mean-field model reproduce the experimental observations. Fluctuations on different facets are typically uncorrelated but within a single facet a high degree of spatial cohere...

  6. Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

    Science.gov (United States)

    Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

    2016-01-01

    A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

  7. The Glyoxal Clock Reaction

    Science.gov (United States)

    Ealy, Julie B.; Negron, Alexandra Rodriguez; Stephens, Jessica; Stauffer, Rebecca; Furrow, Stanley D.

    2007-01-01

    Research on the glyoxal clock reaction has led to adaptation of the clock reaction to a general chemistry experiment. This particular reaction is just one of many that used formaldehyde in the past. The kinetics of the glyoxal clock makes the reaction suitable as a general chemistry lab using a Calculator Based Laboratory (CBL) or a LabPro. The…

  8. Potential reactivity of the andesitic rocks from Cabo de Gata (SE Spain); Reactividad potencial de las rocas andesiticas de Cabo de Gata (SE de Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, J.; Iglesia, A. la; Garcia Calleja, M. A.; Lopez-Ruiz, J.

    2010-07-01

    Andesitic rocks produce an alkali-silica reaction with the components of the interstitial phase of concrete. This reaction can be considered as belonging to the slow-kinetic type, since the incongruent dissolution of the rock-forming minerals leads to the late formation of siliceous calc-alkaline gel. As a conquence, the conventional mortar-bar method does not detect such reaction until 90 days later. (Author) 9 refs.

  9. Practice Gaps: Drug Reactions.

    Science.gov (United States)

    Wolverton, Stephen E

    2016-07-01

    The term "drug reactions" is relevant to dermatology in three categories of reactions: cutaneous drug reactions without systemic features, cutaneous drug reactions with systemic features, and systemic drugs prescribed by the dermatologist with systematic adverse effects. This article uses examples from each of these categories to illustrate several important principles central to drug reaction diagnosis and management. The information presented will help clinicians attain the highest possible level of certainty before making clinical decisions. PMID:27363888

  10. Planar-transverse amplitude-phase pattern in nonelastic reactions

    International Nuclear Information System (INIS)

    The first evidence is presented that the phase pattern of the planar-transverse optimal reaction amplitudes found previously for elastic-scattering strong-interaction reactions also holds for nonelastic reactions. The pattern is observed in the reaction p+p→d+π in the energy range between 300 and 800 MeV

  11. Planar-transverse amplitude-phase pattern in nonelastic reactions

    Science.gov (United States)

    Arash, Firooz; Moravcsik, Michael J.; Goldstein, Gary R.; Bugg, David V.

    1989-01-01

    The first evidence is presented that the phase pattern of the planar-transverse optimal reaction amplitudes found previously for elastic-scattering strong-interaction reactions also holds for nonelastic reactions. The pattern is observed in the reaction p+p-->d+π in the energy range between 300 and 800 MeV.

  12. Nuclear reactions. An introduction

    International Nuclear Information System (INIS)

    methods and tools with basic theoretical knowledge. Emphasis is placed on the importance of spin and orbital angular momentum (leading e.g. to applications in energy research, such as fusion with polarized nuclei), and on the operational definition of observables in nuclear physics. The end-of-chapter problems serve above all to elucidate and detail physical ideas that could not be presented in full detail in the main text. Readers are assumed to have a working knowledge of quantum mechanics and a basic grasp of both non-relativistic and relativistic kinematics; the latter in particular is a prerequisite for interpreting nuclear reactions and the connections to particle and high-energy physics.

  13. Incomplete fusion reactions

    International Nuclear Information System (INIS)

    Various aspects of the mechanism of heavy-ion induced reactions in the range of bombarding energies from a few to about 20 MeV/A are reviewed with special emphasis on the reactions for very asymmetric systems. Results of the experimental studies of binary reactions and particularly of the incomplete fusion reactions (selected by means of various coincidence techniques)are discussed. A model of generalized critical angular momentum is formulated. The model explains essential features of the incomplete fusion reactions and predicts that particular reaction channels are localized in well defined regions of angular momenta. An extension of this model (the sum-rule model) is also proposed in attempt to consistently describe the complete fusion reactions, incomplete fusion reactions and multibody reactions in the framework of statistical competition constrained by the angular momentum limitations. (author)

  14. 阳性激发点推拿方案治疗足底筋膜炎临床观察%Clinical Observation of Treating Plantar Fasciitis through Positive Reaction Point Massage

    Institute of Scientific and Technical Information of China (English)

    杨扬; 赵雨; 吕建琴

    2012-01-01

    目的 探讨阳性激发点推拿治疗对足底筋膜炎的临床疗效.方法 对2011年3月-8月门诊确诊为足底筋膜炎的52例患者,采用随机方式分为治疗组和对照组各26例,治疗组采用阳性激发点推拿,对照组采用电针治疗.并对两组患者治疗5次后的即时疗效率、日本骨科学会(JOA)足底治疗疗效评分、每次治疗后的疼痛面谱量化评分、3个月随访疼痛复发率等疗效进行对照分析.结果 治疗组和对照组经连续治疗5次后,其JOA足底治疗疗效评分分别为(91.32±10.61)、(82.92±13.61)分,总有效率分别为96.15%、80.77%,差异均有统计学意义(P<0.05).疼痛面谱量化评分,治疗组在第一次治疗后较对照组改善明显,差异有统计学意义(P<0.05).3个月后随访疼痛复发情况,治疗组复发人数较对照组少,差异有统计学意义(P<0.05).结论 阳性激发点推拿治疗法对改善足底筋膜炎引发的足底疼痛、步行不适等症状优于电针治疗法,值得临床推广运用.%Objective To discuss the clinical effects of positive reaction point massage in treating plantar fasciitis. Methods Fifty-two patients diagnosed to have plantar fasciitis between March and August 2011 in our hospital were randomly divided into the treatment group and the control group with 26 patients in each. Patients in the treatment group were treated by positive reaction point massage, while those in the control group were treated by acupuncture. Then, the immediate effective rate after 5 times of treatment, Japanese Orthopedic Association (JOA) Scores, the assessment face scale (AFS) scores, and recurrences after 3 months were compared and analyzed between the two groups of patients. Results After 5 times of continuous treatment, JOA scores for patients in the treatment group and the control group were respectively 91.32 ± 10.61 and 82.92 ± 13.61, and the total effective rate were 96.15% and 80.77% for the two groups, which were

  15. Teachers’ Reactions Towards Misbehavior in the Classroom

    OpenAIRE

    Çoban, Ahmet; Dicle Üniversitesi, Ziya Gökalp Eğitim Fakültesi, Eğitim Bilimleri Bölümü

    2015-01-01

    The purpose of this research is to determine primary school teachers’ reactions towards student misbehavior in the classroom, and to evaluate and analyze these behaviors in terms of different dimensions. We observed the courses of 43 primary school teachers from four different schools. Our aim is to reveal the reactions of primary school teachers towards their students’ misbehavior in the classroom, and whether these reactions change regarding variables such as school, class, and course. Furt...

  16. Interface reactions in film materials

    Institute of Scientific and Technical Information of China (English)

    Fengwu Zhu; Zhonghai Zhai; Guanghua Yu

    2003-01-01

    Interface reaction (IR) is a frequently observed phenomenon in the study of advanced thin film materials. It is very important to study the reaction conditions at which IR happens and then to suppress or make use of it, the necessary conditions, including both thermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems, including oxide/silicon,oxide/metal, metal/metal, metal/semiconductor and semiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were also introduced.

  17. Liquid drop effects in subbarrier transfer reactions

    International Nuclear Information System (INIS)

    Reaction products from a multitude of binary channels are observed to emerge at large c.m. angles at subbarrier energies for the 50Ti + 93Nb system. The energy spectra of these products and the distance where they first emerge indicate that these reaction products result from the neck which is formed outside the Coulomb barrier. 9 refs., 5 figs

  18. Exotic meson production in the f1(1285)π- system observed in the reaction π-p→ηπ+π-π-p at 18 GeV/c

    International Nuclear Information System (INIS)

    This Letter reports results from the partial wave analysis of the π-π-π+η final state in π-p collisions at 18 GeV/c. Strong evidence is observed for production of two mesons with exotic quantum numbers of spin, parity and charge conjugation, JPC=1-+ in the decay channel f1(1285)π-. The mass M=1709±24±41 MeV/c2 and width Γ=403±80±115 MeV/c2 of the first state are consistent with the parameters of the previously observed π1(1600). The second resonance with mass M=2001±30±92 MeV/c2 and width Γ=333±52±49 MeV/c2 agrees very well with predictions from theoretical models. In addition, the presence of π2(1900) is confirmed with mass M=2003±88±148 MeV/c2 and width Γ=306±132±121 MeV/c2 and a new state, a1(2096), is observed with mass M=2096±17±121 MeV/c2 and width Γ=451±41±81 MeV/c2. The decay properties of these last two states are consistent with flux tube model predictions for hybrid mesons with non-exotic quantum numbers

  19. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  20. Microscale Thermite Reactions.

    Science.gov (United States)

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  1. Anaphylaxis-Like Reactions

    Science.gov (United States)

    ... be "primed" by previous exposure to cause anaphylaxis, anaphylactoid reactions can occur with no previous exposure at all. ... an X-ray. Although the mechanism of an anaphylactoid reaction is different, the treatment is the same as ...

  2. Common Reactions After Trauma

    Science.gov (United States)

    ... here Enter ZIP code here Common Reactions After Trauma Public This section is for Veterans, General Public, Family, & Friends Common Reactions After Trauma Available in Spanish: Reacciones Comunes Después de un ...

  3. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately

  4. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  5. Anaphylactoid reactions to paracetamol

    OpenAIRE

    Ayonrinde, O.; Saker, B.

    2000-01-01

    The toxic effects of paracetamol in overdose quantities are well recognised but the occurrence of anaphylactoid reactions to paracetamol is infrequently identified by consumers and health care professionals. Nevertheless adverse reactions to this drug, even in therapeutic doses, can have fatal or near fatal consequences. A case of an anaphylactoid reaction to paracetamol is described.


Keywords: paracetamol; anaphylaxis; allergy; hypersensitivity

  6. Reaction pathways of propene pyrolysis.

    Science.gov (United States)

    Qu, Yena; Su, Kehe; Wang, Xin; Liu, Yan; Zeng, Qingfeng; Cheng, Laifei; Zhang, Litong

    2010-05-01

    The gas-phase reaction pathways in preparing pyrolytic carbon with propene pyrolysis have been investigated in detail with a total number of 110 transition states and 50 intermediates. The structure of the species was determined with density functional theory at B3PW91/6-311G(d,p) level. The transition states and their linked intermediates were confirmed with frequency and the intrinsic reaction coordinates analyses. The elementary reactions were explored in the pathways of both direct and the radical attacking decompositions. The energy barriers and the reaction energies were determined with accurate model chemistry method at G3(MP2) level after an examination of the nondynamic electronic correlations. The heat capacities and entropies were obtained with statistical thermodynamics. The Gibbs free energies at 298.15 K for all the reaction steps were reported. Those at any temperature can be developed with classical thermodynamics by using the fitted (as a function of temperature) heat capacities. It was found that the most favorable paths are mainly in the radical attacking chain reactions. The chain was proposed with 26 reaction steps including two steps of the initialization of the chain to produce H and CH(3) radicals. For a typical temperature (1200 K) adopted in the experiments, the highest energy barriers were found in the production of C(3) to be 203.4 and 193.7 kJ/mol. The highest energy barriers for the production of C(2) and C were found 174.1 and 181.4 kJ/mol, respectively. These results are comparable with the most recent experimental observation of the apparent activation energy 201.9 +/- 0.6 or 137 +/- 25 kJ/mol. PMID:20082392

  7. Trimolecular reactions of uranium hexafluoride with water.

    Science.gov (United States)

    Lind, Maria C; Garrison, Stephen L; Becnel, James M

    2010-04-01

    The hydrolysis reaction of uranium hexafluoride (UF(6)) is a key step in the synthesis of uranium dioxide (UO(2)) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF(6) molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizable barrier of 78.2 kJ x mol(-1), indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO(2) product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF(6) molecules and one water molecule, and (2) the reaction of two water molecules with a single UF(6) molecule. The predicted reaction of two UF(6) molecules with one water molecule displays an interesting "fluorine-shuttle" mechanism, a significant energy barrier of 69.0 kJ x mol(-1) to the formation of UF(5)OH, and an enthalpy of reaction (DeltaH(298)) of +17.9 kJ x mol(-1). The reaction of a single UF(6) molecule with two water molecules displays a "proton-shuttle" mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ x mol(-1) and an exothermic enthalpy of reaction (DeltaH(298)) of -13.9 kJ x mol(-1). The exothermic nature of the overall UF(6) + 2H(2)O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging. PMID:20210345

  8. Method of integral transforms for calculating few-body reactions

    OpenAIRE

    Efros, V. D.; Leidemann, W.; Orlandini, G.

    1998-01-01

    A non-conventional approach to calculating reactions in quantum mechanics is presented. Reaction observables are obtained with bound state calculation techniques. The accuracy of the method to calculate few-nucleon response functions is discussed.

  9. Observation of a Broad Structure at an Invariant Mass of 4.32 GeV/$c^2$ in the Reaction $e^+e^-\\to\\pi^+\\pi^-\\psi(2S)$ Measured at BaBar

    CERN Document Server

    Aubert, B; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, R; Allen, M T; Allison, J; Allmendinger, T; Altenburg, D D; Andreotti, M; Angelini, C; Anulli, F; Arnaud, N; Aston, D; Azzolini, V; Baak, M; Back, J J; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Barate, R; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Battaglia, M; Bauer, J M; Bechtle, P; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Benelli, G; Berger, N; Bernard, D; Berryhill, J W; Best, D S; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bhuyan, B; Bianchi, F; Biasini, M; Biesiada, J; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P C; Blount, N L; Bomben, M; Bondioli, M; Bonneaud, G R; Bosisio, L; Boutigny, D; Bowerman, D A; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Briand, H; Brown, C M; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Bugg, W; Bukin, A D; Bula, R; Burchat, P R; Burke, J P; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Capra, R; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Cenci, R; Chai, X; Chaisanguanthum, K S; Chao, M; Charles, E; Charles, M J; Chauveau, J; Chavez, C A; Chen, A; Chen, C; Chen, E; Chen, J C; Chen, S; Chen, X; Chen, X R; Cheng, B; Cheng, C H; Chia, Y M; Cibinetto, G; Clark, P J; Claus, R; Cochran, J; Coleman, J P; Contri, R; Convery, M R; Cossutti, F; Cottingham, W N; Couderc, F; Covarelli, R; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L; Cristinziani, M; Cunha, A; Curry, S; Côté, D; D'Orazio, A; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; De Nardo, Gallieno; De Sangro, R; De, N; Del Amo-Sánchez, P; Del Buono, L; Del Re, D; Della Ricca, G; Denig, A G; Di Lodovico, F; Di Marco, E; Dingfelder, J C; Dittongo, S; Dong, L; Dorfan, J; Druzhinin, V P; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Ebert, M; Eckhart, E A; Eckmann, R; Edgar, C L; Edwards, A J; Egede, U; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Eyges, V; Fabozzi, F; Faccini, R; Fang, F; Feltresi, E; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Flacco, C J; Flack, R L; Flächer, H U; Flood, K T; Ford, K E; Ford, W T; Forster, I J; Forti, F; Fortin, D; Foulkes, S D; Franek, B; Frey, R; Fritsch, M; Fry, J R; Fulsom, B G; Gabathuler, E; Gaidot, A; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gary, J W; Gaspero, M; Gatto, C; Gaz, A; George, K A; Gill, M S; Giorgi, M A; Gladney, L; Glanzman, T; Godang, R; Golubev, V B; Gowdy, S J; Gradl, W; Graham, M T; Graugès-Pous, E; Grenier, P; Gritsan, A V; Groot; Grosdidier, G; Groysman, Y; Hadavand, H K; Haire, M; Halyo, V; Hamano, K; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, A J; Hartfiel, B L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hill, E J; Hirschauer, J F; Hitlin, D G; Hollar, J J; Hong, T M; Honscheid, K; Hopkins, D A; Hrynóva, T; Hufnagel, D; Hulsbergen, W D; Hutchcroft, D E; Höcker, A; Igonkina, O; Innes, W R; Izen, J M; Jackson, P D; Jackson, P S; Jacobsen, R G; Jain, V; Jasper, H; Jawahery, A; Jessop, C P; John, M J J; Judd, D; Kadyk, J A; Kagan, H; Karyotakis, Yu; Kass, R; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Klose, V; Knecht, N S; Koch, H; Kolomensky, Yu G; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kreisel, A; Krishnamurthy, M; Kroeger, R; Kroseberg, J; Kukartsev, G; Kutter, P E; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lanceri, L; Lange, D J; Lankford, A J; Latham, T E; Latour, E; Lau, Y P; Lazzaro, A; Le Diberder, F R; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Lewandowski, B; Li Gioi, L; Li, S; Li, X; Lista, L; Liu, H; Lo Vetere, M; LoSecco, J M; Lockman, W S; Lombardo, V; Long, O; Lou, X C; Lu, M; Luitz, S; Lund, P; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lü, C; Lüth, V; MacFarlane, D B; Macri, M M; Mader, W F; Majewski, S A; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Marchiori, G; Margoni, M; Marks, J; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Mclachlin, S E; Meadows, B T; Mellado, B; Menges, W; Messner, R; Meyer, N T; Meyer, W T; Mihályi, A; Mir, L M; Mishra, K; Mohanty, G B; Mommsen, R K; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M; Muheim, F; Müller, D R; Nagel, M; Naisbit, M T; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nesom, G; Nicholson, H; Nikolich, M B; Nogowski, R; Nugent, I M; O'Grady, C P; Ocariz, J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Oyanguren, A; Ozcan, V E; Paar, H P; Pacetti, S; Palano, A; Palombo, F; Pan, B; Pan, Y; Panduro-Vazquez, W; Panetta, J; Paolucci, P; Pappagallo, M; Park, W; Passaggio, S; Patel, P M; Patrignani, C; Patteri, P; Payne, D J; Pelizaeus, M; Perazzo, A; Perl, M; Peruzzi, I M; Peters, K; Petersen, B A; Petrella, A; Petzold, A; Piatenko, T; Piccolo, D; Piccolo, M; Piemontese, L; Pierini, M; Piredda, G; Playfer, S; Poireau, V; Polci, F; Pompili, A; Porter, F C; Posocco, M; Prell, S; Prencipe, E; Prepost, R; Pripstein, M; Pruvot, S; Pulliam, T; Purohit, M V; Qi, N D; Rahatlou, S; Rahimi, A M; Rahmat, R; Rama, M; Ratcliff, B N; Raven, G; Ricciardi, S; Richman, J D; Ritchie, J L; Rizzo, G; Roat, C; Roberts, D A; Robertson, A I; Robertson, S H; Robutti, E; Rodier, S; Roe, N A; Ronan, M T; Roney, J M; Rong, G; Roodman, A; Roos, L; Rosenberg, E I; Rotondo, M; Roudeau, P; Rubin, A E; Ruddick, W O; Ryd, A; Röthel, W; Sacco, R; Saeed, M A; Safai-Tehrani, F; Saleem, M; Salnikov, A A; Salvatore, F; Samuel, A; Sanders, D A; Santroni, A; Saremi, S; Satpathy, A; Schalk, T; Schenk, S; Schilling, C J; Schindler, R H; Schofield, K C; Schott, G; Schröder, T; Schröder, H; Schubert, J; Schubert, K R; Schumm, B A; Schune, M H; Schwiening, J; Schwierz, R; Schwitters, R F; Sciacca, C; Sciolla, G; Seiden, A; Sekula, S J; Serednyakov, S I; Sharma, V; Shen, B C; Sherwood, D J; Simard, M; Simi, G; Simonetto, F; Sinev, N B; Skovpen, Y I; Smith, A J S; Smith, J G; Snoek, H L; Snyder, A; Sobie, R J; Soffer, A; Sokoloff, M D; Solodov, E P; Spaan, B; Spanier, S M; Spitznagel, M; Spradlin, P; Steinke, M; Stelzer, J; Stocchi, A; Stoker, D P; Stroili, R; Strom, D; Strube, J; Stugu, B; Stängle, H; Su, D; Sullivan, M K; Summers, D J; Sundermann, J E; Suzuki, K; Swain, S K; Taras, P; Taylor, F; Telnov, A V; Teodorescu, L; Ter-Antonian, R; Therin, G; Thiebaux, C; Thompson, J M; Tisserand, V; Todyshev, Y K; Toki, W H; Torrence, E; Tosi, S; Touramanis, C; Ulmer, K A; Uwer, U; Van Bakel, N; Vasseur, G; Vavra, J; Verderi, M; Viaud, F B; Vitale, L; Voci, C; Voena, C; Volk, A; Wagner, S R; Wagoner, D E; Waldi, R; Walker, D; Walsh, J J; Wang, K; Wang, P; Wang, W F; Wappler, F R; Watson, A T; Weaver, M; Weinstein, A J R; Wenzel, W A; Wilden, L; Williams, D C; Williams, J C; Wilson, F F; Wilson, J R; Wilson, M G; Wilson, R J; Winklmeier, F; Wisniewski, W J; Wittgen, M; Wong, Q K; Wormser, G; Wren, A C; Wright, D H; Wright, D M; Wu, J; Wu, S L; Xie, Y; Yamamoto, R K; Yarritu, A K; Ye, S; Yi, J I; Yi, K; Young, C C; Yu, Z; Yéche, C; Zain, S B; Zallo, A; Zeng, Q; Zghiche, A; Zhang, J; Zhang, L; Zhao, H W; Zhu, Y S; Ziegler, V; Zito, M; Çuhadar-Dönszelmann, T; al, et

    2006-01-01

    We measure the cross section for the process $e^+e^-\\to\\pi^+\\pi^-\\psi(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II $e^+e^-$ storage rings. The study is based on 298 fb$^{-1}$ of data recorded with the BaBar detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. This structure is not compatible with the Y(4260) previously reported by this experiment. A single resonance is adequate to describe the cross-section in the low-energy region ($<$5.7 GeV).

  10. Direct-reaction and isospin symmetries in d + d reactions

    International Nuclear Information System (INIS)

    We have measured angular distributions of the analyzing powers A/sub y/, A/sub x/x, A/sub y/y, and A/sub x/z for the 2H(d,p)3H reaction at deuteron lab energies E/sub d/ of 13.39 and 17.00 MeV. These distributions do not show the symmetry or antisymmetry about 900 (c.m.) expected on the basis of a simple direct-neutron-transfer reaction mechanism. In a companion experiment, we have measured the same four analyzing powers for both the 2H(d,p)3H reaction and its charge-symmetric partner 2H(d,n)3He at E/sub d/ = 15.50 and 17.00 MeV in a restricted angular range. These latter data were obtained by simultaneously detecting the tritons and helions. Only small differences were observed in the respective analyzing powers for the two reactions, which suggests a weakening of the mechanism responsible for the larger differences found by others at lower energies

  11. Noncanonical Reactions of Flavoenzymes

    Directory of Open Access Journals (Sweden)

    Pablo Sobrado

    2012-11-01

    Full Text Available Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel chemistries. Recent mechanistic and structural data supporting novel flavin functionalities in reactions catalyzed by chorismate synthase, type II isopentenyl diphosphate isomerase, UDP-galactopyranose mutase, and alkyl-dihydroxyacetonephosphate synthase are presented in this review. In these enzymes, the flavin plays either a direct role in acid/base reactions or as a nucleophile or electrophile. In addition, the flavin cofactor is proposed to function as a “molecular scaffold” in the formation of UDP-galactofuranose and alkyl-dihydroxyacetonephosphate by forming a covalent adduct with reaction intermediates.

  12. Cosmetic tattoo pigment reaction

    OpenAIRE

    Greywal, Tanya; Cohen, Philip R

    2016-01-01

    BackgroundCutaneous reactions to tattoos are most commonly granulomatous or lichenoid. PurposeWe describe a woman who developed a lymphocytic reaction following a cosmetic tattoo procedure with black dye. The reaction occurred not only at the site of the tattoos (eyebrows and eyelash lines), but also in non-tattooed skin (bilateral malar cheeks). Methods and MaterialsWe reviewed PubMed for the following terms: cosmetic, dye, granuloma, granulomatous, lichenoid, lymphocytic, ...

  13. Anaphylactic reactions to cinoxacin.

    OpenAIRE

    Stricker, B H; Slagboom, G.; Demaeseneer, R.; Slootmaekers, V.; Thijs, I.; Olsson, S

    1988-01-01

    During 1981 to mid-1988 three cases of anaphylactic shock after treatment with the quinolone derivative cinoxacin were reviewed by the Netherlands Centre for Monitoring of Adverse Reactions to Drugs and 17 cases of an anaphylactic type of reaction notified to the World Health Organisation Collaborating Centre for International Drug Monitoring. In five out of six patients for whom data were available the reaction began shortly after taking a single capsule of a second or next course of treatme...

  14. Reaction kinetics of polybutylene terephthalate polycondensation reaction

    NARCIS (Netherlands)

    Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.

    2005-01-01

    The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl tereph

  15. Reactions at Solid Surfaces

    CERN Document Server

    Ertl, Gerhard

    2009-01-01

    Expanding on the ideas first presented in Gerhard Ertl's acclaimed Baker Lectures at Cornell University, Reactions at Solid Surfaces comprises an authoritative, self-contained, book-length introduction to surface reactions for both professional chemists and students alike. Outlining our present understanding of the fundamental processes underlying reactions at solid surfaces, the book provides the reader with a complete view of how chemistry works at surfaces, and how to understand and probe the dynamics of surface reactions. Comparing traditional surface probes with more modern ones, and brin

  16. Desosamine in multicomponent reactions

    NARCIS (Netherlands)

    Achatz, Sepp; Dömling, Alexander

    2006-01-01

    Desosamine occurring ubiquitously in natural products is introduced into isocyanide based multicomponent reaction chemistry. Corresponding products are of potential interest for the design of novel antibiotics. © 2006.

  17. Reaction chemistry of nitrogen species in hydrothermal systems: Simple reactions, waste simulants, and actual wastes

    International Nuclear Information System (INIS)

    Results are presented from hydrothermal reaction systems containing organic components, nitrogen components, and an oxidant. Reaction chemistry observed in simple systems and in simple waste simulants is used to develop a model which presents global nitrogen chemistry in these reactive systems. The global reaction path suggested is then compared with results obtained for the treatment of an actual waste stream containing only C-N-0-H species

  18. The Blue Bottle Reaction as a General Chemistry Experiment on Reaction Mechanisms

    Science.gov (United States)

    Engerer, Steven C.; Cook, A. Gilbert

    1999-11-01

    A kinetics/reaction mechanism experiment using the classic blue bottle reaction is described. Using the scientific method (observe, question, hypothesize, experiment, repeat) students propose and test possible reaction mechanisms for the methylene blue-catalyzed oxidation of dextrose with its dramatic color change. Students are led to discover the three-step mechanism through a series of questions. An advanced version for honors lab courses is also suggested.

  19. Chemical reaction and separation method

    NARCIS (Netherlands)

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.

    2005-01-01

    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  20. Clock Reaction: Outreach Attraction

    Science.gov (United States)

    Carpenter, Yuen-ying; Phillips, Heather A.; Jakubinek, Michael B.

    2010-01-01

    Chemistry students are often introduced to the concept of reaction rates through demonstrations or laboratory activities involving the well-known iodine clock reaction. For example, a laboratory experiment involving thiosulfate as an iodine scavenger is part of the first-year general chemistry laboratory curriculum at Dalhousie University. With…

  1. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  2. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  3. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction

  4. Finkelstein Reaction in Functionalized Crown-ether Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Xiao Hua WANG; Han Zhi WANG; Hui LIU; Yuan KOU

    2006-01-01

    Functional crown-ether ionic liquids were used as catalytic green solvents of Finkelstein reaction of 1-bromooctane and iodide. The rate and yield of the reaction were obvious improved compared with that using crown ether in water. No free crown ether loss was observed after reaction.

  5. Note on interference effects in two-step reaction processes

    International Nuclear Information System (INIS)

    The reaction processes in which a one-step transition is forbidden are analyzed from the point of view of the first order perturbation theory. The interference between two competing two-step reaction paths is found to be always constructive. A qualitative explanation of the experimentally observed reaction intensities is presented. (author)

  6. Nuclear Reactions from Lattice QCD

    CERN Document Server

    Briceño, Raúl A; Luu, Thomas C

    2014-01-01

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path ...

  7. Performance Characteristics of Waste Glass Powder Substituting Portland Cement in Mortar Mixtures

    OpenAIRE

    Kara, P; Csetényi, L; Borosnyói, A

    2014-01-01

    In several countries, waste glass causes environmental concerns as quantities stockpiled exceed recycling in the packaging stream. Being amorphous and having relatively high silicium and calcium contents, glass is pozzolanic or even cementitious, when finely ground. Reducing particle sizes typically to less than 100 µm may give control over the alkali-silica reaction in concrete, therefore making this material a possible substitute to Portland cement. Such use may moderate the problem of dump...

  8. Caracterização de produtos de deterioração do betão por métodos petrográficos

    OpenAIRE

    Rodrigues, A. P.; Fernandes, I; Noronha, F.

    2010-01-01

    This study aimed to characterize the products of deterioration of concrete by petrographicmethods. Samples from seven concrete structures as well as three samples produced in laboratory testswere studied. The external evidence of deterioration of the structures were confirmed by petrographicmicroscope and analysis by scanning electron microscope / spectrometer energy dispersion lead to theidentification of alkali-silica gel, trona, ettringite, gypsum and thaumasite as reaction products

  9. In situ AFM Observations of Li-Oxygen Electrochemical Reactions

    OpenAIRE

    Katharajan, Hariharan; Virwani, Kumar; Erpelding, A. David; Garcia, Jeannette M.

    2016-01-01

    The morphologies of crystalline lithium peroxide (Li2O2) discharge products in Li-O2 batteries have been shown to exhibit a dependency on subtle variations within the battery cell-operating environment including exposure to ambient air, moisture, or additives. As a result, imaging battery discharge products in real time under carefully controlled environmental conditions is a challenging obstacle for complete mechanistic understanding of Li2O2 growth and deposition during discharge in metal-a...

  10. Isovector spin observables in nuclear charge reactions at LAMPF

    International Nuclear Information System (INIS)

    LAMPF has undertaken a major development program to upgrade facilities for nuclear charge-exchange studies at intermediate energies. The major components of this upgrade are a medium-resolution spectrometer and neutron time-of-flight system for good resolution (δ E < 1 MeV) charge-exchange perograms in (n,p) and (p,n) respectively. Major emphasis is placed on polarization phenomena using polarized beams and analyzing the polarization of the outgoing particle

  11. Hypersensitivity reactions to corticosteroids.

    Science.gov (United States)

    Vatti, Rani R; Ali, Fatima; Teuber, Suzanne; Chang, Christopher; Gershwin, M Eric

    2014-08-01

    Hypersensitivity reactions to corticosteroids (CS) are rare in the general population, but they are not uncommon in high-risk groups such as patients who receive repeated doses of CS. Hypersensitivity reactions to steroids are broadly divided into two categories: immediate reactions, typically occurring within 1 h of drug administration, and non-immediate reactions, which manifest more than an hour after drug administration. The latter group is more common. We reviewed the literature using the search terms "hypersensitivity to steroids, adverse effects of steroids, steroid allergy, allergic contact dermatitis, corticosteroid side effects, and type I hypersensitivity" to identify studies or clinical reports of steroid hypersensitivity. We discuss the prevalence, mechanism, presentation, evaluation, and therapeutic options in corticosteroid hypersensitivity reactions. There is a paucity of literature on corticosteroid allergy, with most reports being case reports. Most reports involve non-systemic application of corticosteroids. Steroid hypersensitivity has been associated with type I IgE-mediated allergy including anaphylaxis. The overall prevalence of type I steroid hypersensitivity is estimated to be 0.3-0.5%. Allergic contact dermatitis (ACD) is the most commonly reported non-immediate hypersensitivity reaction and usually follows topical CS application. Atopic dermatitis and stasis dermatitis of the lower extremities are risk factors for the development of ACD from topical CS. Patients can also develop hypersensitivity reactions to nasal, inhaled, oral, and parenteral CS. A close and detailed evaluation is required for the clinician to confirm the presence of a true hypersensitivity reaction to the suspected drug and choose the safest alternative. Choosing an alternative CS is not only paramount to the patient's safety but also ameliorates the worry of developing an allergic, and potentially fatal, steroid hypersensitivity reaction. This evaluation becomes

  12. The Reaction Wheel Pendulum

    CERN Document Server

    Block, Daniel J; Spong, Mark W

    2007-01-01

    This monograph describes the Reaction Wheel Pendulum, the newest inverted-pendulum-like device for control education and research. We discuss the history and background of the reaction wheel pendulum and other similar experimental devices. We develop mathematical models of the reaction wheel pendulum in depth, including linear and nonlinear models, and models of the sensors and actuators that are used for feedback control. We treat various aspects of the control problem, from linear control of themotor, to stabilization of the pendulum about an equilibrium configuration using linear control, t

  13. Electron transfer reactions

    CERN Document Server

    Cannon, R D

    2013-01-01

    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  14. Modification of the tuberculin reaction by levan.

    Science.gov (United States)

    Shezen, E.; Leibovici, J.; Wolman, M.

    1978-01-01

    High molecular levan (polyfructoside) inhibits the skin tuberculin reaction in guinea pigs as judged by the degree of induration and erythema. The effect is dose-dependent. No effect on cellular infiltration was observed in histological studies. The lymph nodes of levan-treated animals were smaller and exhibited a much milder granulomatous reaction than those of non-treated animals. Images Fig. 2 Fig. 3 PMID:718799

  15. Competitive Reactions to Advertising and Promotion Attacks

    OpenAIRE

    Jan-Benedict E. M. Steenkamp; Vincent R. Nijs; Dominique M. Hanssens; Dekimpe, Marnik G.

    2005-01-01

    How do competitors react to each other's price-promotion and advertising attacks? What are the reasons for the observed reaction behavior? We answer these questions by performing a large-scale empirical study on the short-run and long-run reactions to promotion and advertising shocks in over 400 consumer product categories over a four-year time span. Our results clearly show that the most predominant form of competitive response is passive in nature. When a reaction does occur, it is usually ...

  16. Competitive reactions to advertising and promotion attacks.

    OpenAIRE

    Steenkamp, Jan-Benedict E.M.; Vincent R. Nijs; Hanssens, Dominique M; Dekimpe, Marnik G.

    2005-01-01

    How do competitors react to each other's price-promotion and advertising attacks? What are the reasons for the observed reaction behavior? We answer these questions by performing a large-scale empirical study on the short-run and long-run reactions to promotion and advertising shocks in over 400 consumer product categories over a four-year time span. Our results clearly show that the most predominant form of competitive response is passive in nature. When a reaction does occur, it is usually ...

  17. Resonance effects in fusion and transfer reactions

    International Nuclear Information System (INIS)

    Recent results from fusion and transfer reactions are reviewed together with information they provide for understanding resonance phenomena present in other channels. From present understanding of elastic scattering to a consideration of fusion and the direct reaction channels the discussion covers light nucleus--nucleus systems with targets of A = 10 to 18, reactions of 12C and 16O ions on target nuclei A = 20 to 58, an attempt to characterize the relevant features which have emerged thus far, and parallels with the behaviors observed in the light systems. 69 references

  18. Fractional diffusion equations coupled by reaction terms

    Science.gov (United States)

    Lenzi, E. K.; Menechini Neto, R.; Tateishi, A. A.; Lenzi, M. K.; Ribeiro, H. V.

    2016-09-01

    We investigate the behavior for a set of fractional reaction-diffusion equations that extend the usual ones by the presence of spatial fractional derivatives of distributed order in the diffusive term. These equations are coupled via the reaction terms which may represent reversible or irreversible processes. For these equations, we find exact solutions and show that the spreading of the distributions is asymptotically governed by the same the long-tailed distribution. Furthermore, we observe that the coupling introduced by reaction terms creates an interplay between different diffusive regimes leading us to a rich class of behaviors related to anomalous diffusion.

  19. Clinical Observation of Diphenhydramine Combined with Prednisone in the Prevention of Iodine-containing Contrast Agent Allergic Reactions%苯海拉明联合泼尼松预防碘造影剂过敏反应的临床观察

    Institute of Scientific and Technical Information of China (English)

    胡立禄; 高全清; 刘振良

    2016-01-01

    OBJECTIVE:To observe the success rate and safety of diphenhydramine combined with prednisone in the preven-tion of iodine-containing contrast agent allergic reactions. METHODS:1 day before surgery,42 patients with positive iodine aller-gy test was given 40 mg Prednisone tablet,orally,3 times a day,50 mg diphenhydramine was given by intramuscular injection and 1 ml iodine contrast by intravenous injection(allergy test performed again)1 h before surgery. After all patients used iodine con-trast in 15 min,vascular interventional treatment was conducted if there was no bronchospasm,angioedema,leather ball sample itchy rash,hypotension,itching and other allergic reactions. Prevention success rate were observed,and the incidence of adverse re-actions was recorded. RESULTS:Prevention success rate was 90.48%,the incidence of adverse reactions was 7.14%,and it self-improved after stopping drugs. CONCLUSIONS:Diphenhydramine combined with prednisone has high success rate in the pre-vention of iodine-containing contrast agent allergic reactions,with good safety.%目的:观察苯海拉明联合泼尼松预防碘造影剂过敏反应的成功率和安全性。方法:42例碘过敏试验呈阳性患者于术前1 d给予泼尼松片40 mg,口服,每日3次,术前1 h给予苯海拉明50 mg,肌内注射,并同时静脉注射碘造影剂1 ml(再次进行过敏试验)。所有患者使用碘造影剂15 min后若不存在支气管痉挛、血管性水肿、皮团样皮疹、低血压、瘙痒等过敏反应,方可行血管介入治疗。观察42例患者预防成功率及不良反应发生情况。结果:预防成功率为90.48%;不良反应发生率为7.14%,经停药后症状均自行好转。结论:苯海拉明联合泼尼松预防碘造影剂过敏反应具有较高的成功率,安全性较好。

  20. Autocatalysis in reaction networks.

    Science.gov (United States)

    Deshpande, Abhishek; Gopalkrishnan, Manoj

    2014-10-01

    The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is that if all reactions are reversible in a weak sense, then no species can go extinct. A notion that has been found useful in thinking about persistence is that of "critical siphon." We explore the combinatorics of critical siphons, with a view toward the persistence conjecture. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: Every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and nonautocatalytic weakly reversible networks are persistent. Our results clarify that the difficulties in proving the persistence conjecture are essentially due to competition between drainable and self-replicable siphons. PMID:25245394

  1. Chemisorption And Precipitation Reactions

    Science.gov (United States)

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  2. Nucleon induced reactions

    International Nuclear Information System (INIS)

    The collection contains full texts of 37 contributions; all fall within the INIS Subject Scope. The topics treated include some unsolved problems of nuclear reactions and relevant problems of nuclear structure at low and intermediate energies. (Z.S.)

  3. Allergic reactions in anaesthesia

    DEFF Research Database (Denmark)

    Krøigaard, M; Garvey, L H; Menné, T;

    2005-01-01

    BACKGROUND: The aim of this retrospective survey of possible allergic reactions during anaesthesia was to investigate whether the cause suspected by anaesthetists involved corresponded with the cause found on subsequent investigation in the Danish Anaesthesia Allergy Centre (DAAC). METHODS: Case...... notes and anaesthetic charts from 111 reactions in 107 patients investigated in the DAAC were scrutinized for either suspicions of or warnings against specific substances stated to be the cause of the supposed allergic reaction. RESULTS: In 67 cases, one or more substances were suspected. In 49 of these...... match, the right substance being suspected, but investigations showed an additional allergen or several substances, including the right substance being suspected. CONCLUSIONS: An informed guess is not a reliable way of determining the cause of a supposed allergic reaction during anaesthesia and may put...

  4. Ofloxacin induced hypersensitivity reaction

    Directory of Open Access Journals (Sweden)

    Hari Babu Ramineni

    2015-01-01

    Full Text Available Ofloxacin is a commonly used antimicrobial agent to combat various infections. The adverse profile of quinolones includes gastrointestinal symptoms, which are the most frequent, neuropsychiatric symptoms, hematologic abnormalities are less common. We report a rare case of ofloxacin induced hypersensitivity reaction in a 57 year old female patient with complaints of rashes over the axilla, upper limb and back, abdomen, thorax associated with exfoliation of skin all over the axilla associated with severe itching. Based on history and clinical examination patient was diagnosed as ofloxacin induced hypersensitivity reaction and was successfully treated with antihistamines and corticosteroids. Pharmacovigilance should be a part of patient care in order to reduce occurrence of adverse drug reaction and also encourage practitioners in reporting so as to gather more and more data regarding adverse drug reactions. [Int J Res Med Sci 2015; 3(1.000: 349-351

  5. Adverse reactions to cosmetics

    OpenAIRE

    Dogra A; Minocha Y; Kaur S

    2003-01-01

    Adverse reaction to cosmetics constitute a small but significant number of cases of contact dermatitis with varied appearances. These can present as contact allergic dermatitis, photodermatitis, contact irritant dermatitis, contact urticaria, hypopigmentation, hyperpigmentotion or depigmentation, hair and nail breakage. Fifty patients were included for the study to assess the role of commonly used cosmetics in causing adverse reactions. It was found that hair dyes, lipsticks and surprisingly ...

  6. Meson production in + reactions

    Indian Academy of Sciences (India)

    H Machner; M Betigeri; J Bojowald; A Budzanowski; A Chatterjee; J Ernst; L Freindl; D Frekers; W Garske; K Grewer; A Hamacher; J Ilieva; L Jarczyk; K Kilian; S Kliczewski; W Klimala; D Kolev; T Kutsarova; J Lieb; H Machner; A Magiera; H Nann; L Pentchev; H S Plendl; D Protić; B Razen; P Von Rossen; B J Roy; R Siudak; J Smyrski; R V Srikantiah; A Strzałkowski; R Tsenov; K Zwoll

    2001-08-01

    Total and differential cross sections for the reactions $p+d → 3He + 0 with = ; and + → 3H + + were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward–backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied.

  7. Oxygen evolution reaction catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  8. EXERCISE AND REACTION TIMES

    OpenAIRE

    Varun; Neeraj; Ushadhar; Yogesh; Rinku

    2015-01-01

    OBJECTIVES: Physical exercise provides multiple benefits to an individual. It is known that exercising regularly can prevent coronary heart disease, hypertension and obesity and improve flexibility. The effect of exercise on visual reaction time needs to be studied, a s the existing data on the benefit of aerobic exercise on psychomotor functions is insufficient. MATERIALS AND METHODS: Online Visual reaction time is measured before and after exercise. Subjects were ...

  9. The power-law reaction rate coefficient for barrierless reactions

    OpenAIRE

    Yin, Cangtao; Du, Jiulin

    2014-01-01

    The power-law reaction rate coefficient for the barrierless reactions is studied if the reactions take place in systems with power-law distributions, and a generalized rate formula for the barrierless reactions in Gorin model is derived. We show that due to barrierless, different from those for bimolecular and unimolcular reactions, the power-law rate coefficient for the barrierless reactions does not have the factor of power-law distribution function and thus it is not very strongly dependen...

  10. Satellite observations

    Science.gov (United States)

    1984-05-01

    In 1982 and 1983, six scientific satellites were operated successfully. Two of them, JIKIKEN and ISS-b, performed observations of the Earth's plasma environment. HINOTORI, the solar maximum satellite, observed a number of solar flares. HAKUCHO and newly launched TENMA conducted various observations of cosmic X-ray sources. HIMAWARI-2 is a meteorological satellite but its payload includes a solar particle monitor. EXOS-C was successfully launched in February, 1983, and participants in the MAP (Middle Atmosphere Program). Following these missions, the PLANET-A project comprising two missions, MS-T5 and PLANET-A, is under preparation for the participation in the international cooperative exploration of Comet P/Halley. The third X-ray astronomy satellite ASTRO-C is currently scheduled for 1987 launch.

  11. Observational $\\Delta\

    CERN Document Server

    Hernández, Antonio García; Monteiro, Mário J P F G; Suárez, Juan Carlos; Reese, Daniel R; Pascual-Granado, Javier; Garrido, Rafael

    2015-01-01

    Delta Scuti ($\\delta$ Sct) stars are intermediate-mass pulsators, whose intrinsic oscillations have been studied for decades. However, modelling their pulsations remains a real theoretical challenge, thereby even hampering the precise determination of global stellar parameters. In this work, we used space photometry observations of eclipsing binaries with a $\\delta$ Sct component to obtain reliable physical parameters and oscillation frequencies. Using that information, we derived an observational scaling relation between the stellar mean density and a frequency pattern in the oscillation spectrum. This pattern is analogous to the solar-like large separation but in the low order regime. We also show that this relation is independent of the rotation rate. These findings open the possibility of accurately characterizing this type of pulsator and validate the frequency pattern as a new observable for $\\delta$ Sct stars.

  12. Clinical Observation of the Effect of Thermal Insulation on the Intraopera-tive Stress Reaction of 68 Patients in the Operating Room%保温护理对68例手术室患者术中应激影响的临床观察

    Institute of Scientific and Technical Information of China (English)

    张瑾

    2015-01-01

    Objective To observe the clinical effect of thermal insulation on the intraoperative stress reaction of patients in the op-erating room. Methods 136 cases with surgery admitted in the Department of Surgery of our hospital from May 2012 to May 2014 were randomly divided into the control group(n=68) and the observation group(n=68), treated by the conventional nursing, thermal insulation, respectively. And the physiological stress response was compared between the two groups. Results The physiological stress response decreased significantly in both groups after surgery compared with before surgery, and that decreased more obvious-ly in the observation group than in the control group (P<0.05). The level of physiological indexes lowered significantly in both groups after surgery compared with before surgery, and that lowered more obviously in the observation group than in the control group(P<0.05). The scores of patients' satisfaction with therapeutic effect, operation, attitude, environment and propaganda and ed-ucation were much better in the observation group than those in the control group(P<0.05). The level of physiological indexes low-ered significantly in both groups after surgery compared with before surgery, and that lowered more obviously in the observation group than in the control group(P<0.05). The scores of level of patients' satisfaction with therapeutic effect, operation, attitude, en-vironment and propaganda and education were much higher in the observation group than those in the control group (P<0.05). Conclusion Thermal insulation can significantly improve the stress reaction in patients in the operating room, enhance the quality of nursing, and make the patients recover quickly with good clinical application value.%目的:探讨保温护理对手术室患者术中应激影响的临床效果。方法整群选取2012年5月-2014年5月在该院外科收治的手术的136例患者随机分为对照组(n=68,予以常规护理)和观察组(n=68,

  13. In situ observation of surface reactions with synchrotron radiation induced semiconductor processes by infrared reflection absorption spectroscopy using buried metal layer substrates; Umekomi kinzokuso kiban wo mochiita sekigai hansha kyushu supekutoruho ni yoru hoshako reiki handotai process hanno no sonoba kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshigoe, A.; Hirano, S. [The Graduate University for Advanced Studies, Yokohama (Japan); Mase, K.; Urisu, T. [Institute for Molecular Science, Aichi (Japan)

    1996-11-20

    It is known that infrared reflection absorption spectroscopy (IRAS) on semiconductor or insulator surfaces becomes practicable by using buried metal layer (BML) substrates, in which the metal thin film is buried order semiconductor or insulator films. In this work, IRAS has been measured for Langmuir-Blodgett films deposited on the BML substrate with SiO2/Al/Si(100) structure and the observed spectrum intensity has been quantitatively compared with the calculation assuming the ideal multilayer structure for the BML substrate. The BML-IRAS using CoSi2 has been adopted to the detection of SiHn on the Si (100) substrate during synchrotron radiation (SR) stimulated Si2H6 gas source molecular beam epitaxy. It has been found that SiH2 and SiH3 on the Si (100) surface are easily decomposed by SR, but SiH can`t be decomposed. From these experiments, it has been concluded that the BML-IRAS is an useful in situ observation technique for the photo-stimulated surface reactions. 26 refs., 9 figs.

  14. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  15. Marketing Mix Reactions to Entry

    OpenAIRE

    Robinson, William T.

    1988-01-01

    Initial product, distribution, marketing expenditure, and price reactions by incumbents are examined for 115 entrants into oligopolistic markets. The most common reaction pattern is either no reaction or only a single reaction. It is very unusual for entrants to face reactions across the entire marketing mix. Reactions in the first two years after entry are explained as a function of the entrant's strategy, incumbent characteristics, and industry characteristics. The explanation provides insi...

  16. Introduction to chemical reaction engineering

    International Nuclear Information System (INIS)

    This deals with chemical reaction engineering with thirteen chapters. The contents of this book are introduction on reaction engineering, chemical kinetics, thermodynamics and chemical reaction, abnormal reactor, non-isothermal reactor, nonideal reactor, catalysis in nonuniform system, diffusion and reaction in porosity catalyst, design catalyst heterogeneous reactor in solid bed, a high molecule polymerization, bio reaction engineering, reaction engineering in material process, control multi-variable reactor process using digital computer.

  17. Macroscopic observables

    International Nuclear Information System (INIS)

    We study macroscopic observables defined as the total value of a physical quantity over a collection of quantum systems. We show that previous results obtained for an infinite ensemble of identically prepared systems lead to incorrect conclusions for finite ensembles. In particular, exact measurement of a macroscopic observable significantly disturbs the state of any finite ensemble. However, we show how this disturbance can be made arbitrarily small when the measurements are of finite accuracy. We demonstrate a general trade-off between state disturbance and measurement coarseness as a function of the size of the ensemble. Using this trade-off, we show that the histories generated by any sequence of finite accuracy macroscopic measurements always generate a consistent family in the absence of large-scale entanglement for sufficiently large ensembles. Hence, macroscopic observables behave 'classically' provided that their accuracy is coarser than the quantum correlation length scale of the system. The role of these observable is also discussed in the context of NMR quantum information processing and bulk ensemble quantum state tomography

  18. Babylonian observations

    Science.gov (United States)

    Brown, D.

    Very few cuneiform records survive from Mesopotamia of datable astronomical observations made prior to the mid-eighth century BC. Those that do record occasional eclipses, and in one isolated case the dates of the heliacal rising and setting of Venus over a few years sometime in the first half of the second millennium BC. After the mid-eighth century BC the situation changes dramatically. Incomplete records of daily observations of astronomical and meteorological events are preserved from c. 747 BC until the Christian Period. These records are without accompanying ominous interpretation, although it is highly probable that they were compiled by diviners for astrological purposes. They include numerous observations of use to historical astronomers, such as the times of eclipses and occultations, and the dates of comet appearances and meteor showers. The question arises as to why such records do not survive from earlier times; celestial divination was employed as far back as the third millenium BC. It is surely not without importance that the earliest known accurate astronomical predictions accompany the later records, and that the mid-eighth century BC ushered in a period of centralised Assyrian control of Mesopotamia and the concomitant employment by the Assyrian ruler of large numbers of professional celestial diviners. The programme of daily observations evidently began when a high premium was first set on the accurate astronomical prediction of ominous events. It is in this light that we must approach this valuable source material for historical astronomy.

  19. Flare Observations

    Directory of Open Access Journals (Sweden)

    Benz Arnold O.

    2008-02-01

    Full Text Available Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting reconnection of magnetic field lines as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s lower ionosphere. While flare scenarios have slowly converged over the past decades, every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  20. Minisatellite Attitude Guidance Using Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Ion STROE

    2015-06-01

    Full Text Available In a previous paper [2], the active torques needed for the minisatellite attitude guidance from one fixed attitude posture to another fixed attitude posture were determined using an inverse dynamics method. But when considering reaction/momentum wheels, instead of this active torques computation, the purpose is to compute the angular velocities of the three reaction wheels which ensure the minisatellite to rotate from the initial to the final attitude. This paper presents this computation of reaction wheels angular velocities using a similar inverse dynamics method based on inverting Euler’s equations of motion for a rigid body with one fixed point, written in the framework of the x-y-z sequence of rotations parameterization. For the particular case A=B not equal C of an axisymmetric minisatellite, the two computations are compared: the active torques computation versus the computation of reaction wheels angular velocities ̇x , ̇y and ̇z. An interesting observation comes out from this numerical study: if the three reaction wheels are identical (with Iw the moment of inertia of one reaction wheel with respect to its central axis, then the evolutions in time of the products between Iw and the derivatives of the reaction wheels angular velocities, i.e. ̇ , ̇ and ̇ remain the same and do not depend on the moment of inertia Iw.

  1. Adverse reactions to cosmetics

    Directory of Open Access Journals (Sweden)

    Dogra A

    2003-03-01

    Full Text Available Adverse reaction to cosmetics constitute a small but significant number of cases of contact dermatitis with varied appearances. These can present as contact allergic dermatitis, photodermatitis, contact irritant dermatitis, contact urticaria, hypopigmentation, hyperpigmentotion or depigmentation, hair and nail breakage. Fifty patients were included for the study to assess the role of commonly used cosmetics in causing adverse reactions. It was found that hair dyes, lipsticks and surprisingly shaving creams caused more reaction as compared to other cosmetics. Overall incidence of contact allergic dermatitis seen was 3.3% with patients own cosmetics. Patch testing was also done with the basic ingredients and showed positive results in few cases where casual link could be established. It is recommended that labeling of the cosmetics should be done to help the dermatologists and the patients to identify the causative allergen in cosmetic preparation.

  2. Reaction Qualifications Revisited

    DEFF Research Database (Denmark)

    Lippert-Rasmussen, Kasper

    2009-01-01

      When, in a competitive sphere, people are selected on the basis of qualifications only, their chances of acquiring positions of advantage may seem to depend entirely upon their abilities, not discriminatory bias. However, if reaction qualifications - i.e. characteristics which contribute...... of merit. Specifically, it preserves symmetry between negative evaluations of antimeritocratic bases of selection and negative evaluations of qualifications rooted in comparable antimeritocratic reactions. So if employers should not select among applicants on the basis of their (the employers') racial...... preferences, recipients should not respond to the applicant actually hired on the basis of their (the recipients') racial preferences. My account decomposes the meritocratic ideal into four separate norms, one of which applies to recipients rather than to selectors. Finally, it defends the view that reaction...

  3. A dynamical model of surrogate reactions

    CERN Document Server

    Aritomo, Y; Nishio, K

    2010-01-01

    A new dynamical model is developed to describe the whole process of surrogate reactions; transfer of several nucleons at an initial stage, thermal equilibration of residues leading to washing out of shell effects and decay of populated compound nuclei are treated in a unified framework. Multi-dimensional Langevin equations are employed to describe time-evolution of collective coordinates with a time-dependent potential energy surface corresponding to different stages of surrogate reactions. The new model is capable of calculating spin distributions of the compound nuclei, one of the most important quantity in the surrogate technique. Furthermore, various observables of surrogate reactions can be calculated, e.g., energy and angular distribution of ejectile, and mass distributions of fission fragments. These features are important to assess validity of the proposed model itself, to understand mechanisms of the surrogate reactions and to determine unknown parameters of the model. It is found that spin distribut...

  4. Reaction between drug substances and pharmaceutical excipients

    DEFF Research Database (Denmark)

    Larsen, Jesper; Cornett, Claus; Jaroszewski, Jerzy Witold;

    2009-01-01

    The reactivity of citric acid towards drug substances in the solid state was examined using the beta-blocker carvedilol as a model compound. The reaction mixtures were analysed by LC-MS, the reaction products were isolated by preparative HPLC, and the structures were elucidated by microprobe NMR...... spectroscopy. Heating a mixture of solid carvedilol and solid citric acid monohydrate for 96h at 50 degrees C resulted in the formation of about 3% of a symmetrical ester as well as of a number of other reaction products in smaller amounts. Formation of the symmetrical ester was also observed at room...... temperature. At 70 degrees C, the amounts of three isomeric esters formed reached 6-8%. The minor reaction products were citric acid amides, O-acetylcarvedilol, and esters of itaconic acid....

  5. Interfacial Reaction Kinetics

    OpenAIRE

    O'Shaughnessy, Ben; Vavylonis, Dimitrios

    1998-01-01

    We study irreversible A-B reaction kinetics at a fixed interface separating two immiscible bulk phases, A and B. We consider general dynamical exponent $z$, where $x_t\\sim t^{1/z}$ is the rms diffusion distance after time $t$. At short times the number of reactions per unit area, $R_t$, is {\\em 2nd order} in the far-field reactant densities $n_A^{\\infty},n_B^{\\infty}$. For spatial dimensions $d$ above a critical value $d_c=z-1$, simple mean field (MF) kinetics pertain, $R_t\\sim Q_b t n_A^{\\in...

  6. Investigating Reaction-Driven Cracking

    Science.gov (United States)

    Kelemen, P. B.; Hirth, G.; Savage, H. M.

    2013-12-01

    for constant volume replacement. Natural examples have fracture energy densities due to strain energy density of 100's of MPa [2]. Despite theory and observation, until now lab experiments on peridotite hydration and carbonation have not produced reaction-driven cracking. Slow kinetics and limited reactive surface area in low porosity samples may be the cause. Also, maximum stress may be limited by 'disjoining pressure', above which nano-films along grain boundaries collapse, and crystal growth essentially ceases [7]. To address these issues, we've begun experiments on analog materials with fast reaction rates, e.g., CaO + H2O = Ca(OH)2, to efficiently investigate the role of confining pressure and other factors on reaction-driven fracture events. Intriguingly, commercially available 'demolition mortar', largely CaO, produces stresses of 70 MPa or more around 1 inch bore holes at room T and P [8], even though there is a free surface at the top of the borehole, and hydration in a 'closed' system creates ~ 40% air-filled pore space. [1] Jamtveit et al EPSL 08 [2] Kelemen & Hirth EPSL 12 [3] Kelemen et al AREPS 11 [4] Aharonov et al JGR 98 [5] Fletcher & Merino GCA 01 [6] Macdonald & Fyfe T'phys 85 [7] Espinosa-Marzal & Scherer GSL Special Papers 10 [8] Laefer et al Mag Concrete Res 10

  7. Observing environments

    DEFF Research Database (Denmark)

    Alrøe, Hugo Fjelsted; Noe, Egon

    2012-01-01

    Context: Society is faced with “wicked” problems of environmental sustainability, which are inherently multiperspectival, and there is a need for explicitly constructivist and perspectivist theories to address them. Problem: However, different constructivist theories construe the environment in...... different ways. The aim of this paper is to clarify the conceptions of environment in constructivist approaches, and thereby to assist the sciences of complex systems and complex environmental problems. Method: We describe the terms used for “the environment” in von Uexküll, Maturana & Varela, and Luhmann......, and analyse how their conceptions of environment are connected to differences of perspective and observation. Results: We show the need to distinguish between inside and outside perspectives on the environment, and identify two very different and complementary logics of observation, the logic of...

  8. Biomixing by chemotaxis and efficiency of biological reactions: the critical reaction case

    CERN Document Server

    Kiselev, Alexander

    2012-01-01

    Many phenomena in biology involve both reactions and chemotaxis. These processes can clearly influence each other, and chemotaxis can play an important role in sustaining and speeding up the reaction. In continuation of our earlier work, we consider a model with a single density function involving diffusion, advection, chemotaxis, and absorbing reaction. The model is motivated, in particular, by the studies of coral broadcast spawning, where experimental observations of the efficiency of fertilization rates significantly exceed the data obtained from numerical models that do not take chemotaxis (attraction of sperm gametes by a chemical secreted by egg gametes) into account. We consider the case of the weakly coupled quadratic reaction term, which is the most natural from the biological point of view and was left open. The result is that similarly to higher power coupling, the chemotaxis plays a crucial role in ensuring efficiency of reaction. However, mathematically, the picture is quite different in the qua...

  9. Managing Your Emotional Reactions

    Science.gov (United States)

    ... takes a bit more practice for some people. Learning to React Well Managing emotional reactions means choosing how and when to express ... easier to make choices that work out well. Learning to react well takes ... at taking emotional situations in stride and expressing emotions in healthy ...

  10. Chain Reaction Polymerization.

    Science.gov (United States)

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  11. The Gewald multicomponent reaction

    NARCIS (Netherlands)

    Huang, Yijun; Doemling, Alexander

    2011-01-01

    The Gewald reaction of sulfur, cyanoacetic acid derivatives, and oxo-component (G-3CR) yielding highly substituted 2-aminothiophene derivatives has seen diverse applications in combinatorial and medicinal chemistry. Its products are of great use in pharmaceutical industry mainly as small molecular w

  12. Explaining competitive reaction effects

    NARCIS (Netherlands)

    Leeflang, P.S.H.; Wittink, D.R.

    2001-01-01

    Changes in promotional expenditure decisions for a brand, as in other marketing decisions, should be based on the expected impact on purchase and consumption behavior as well as on the likely reactions by competitors. Purchase behavior may be predicted from estimated demand functions. Competitive re

  13. Relativistic heavy ion reactions

    International Nuclear Information System (INIS)

    Relativistic heavy ion reactions are reviewed in terms of our present understanding of some selected experimental results from the LBL Bevalac and the CERN ISR. The Lund Model for nucleus-nucleus collisions is presented and its power of predictivity is illustrated. (authors)

  14. Reaction Formulation: A Bibliography.

    Science.gov (United States)

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  15. Reaction product imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  16. Oral Hypersensitivity Reactions

    Science.gov (United States)

    ... and ulcers. Affected individuals may complain of a burning sensation and mouth sensitivity to cold, hot, and spicy foods. Lichenoid ... melon, and pineapple, are all associated with this syndrome. You should inform your ... reaction in the mouth, though some are more common than others. If ...

  17. Photoneutron reactions in astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Varlamov, V. V., E-mail: Varlamov@depni.sinp.msu.ru; Ishkhanov, B. S.; Orlin, V. N.; Peskov, N. N.; Stopani, K. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

    2014-12-15

    Among key problems in nuclear astrophysics, that of obtaining deeper insight into the mechanism of synthesis of chemical elements is of paramount importance. The majority of heavy elements existing in nature are produced in stars via radiative neutron capture in so-called s- and r processes, which are, respectively, slow and fast, in relation to competing β{sup −}-decay processes. At the same time, we know 35 neutron-deficient so-called bypassed p-nuclei that lie between {sup 74}Se and {sup 196}Hg and which cannot originate from the aforementioned s- and r-processes. Their production is possible in (γ, n), (γ, p), or (γ, α) photonuclear reactions. In view of this, data on photoneutron reactions play an important role in predicting and describing processes leading to the production of p-nuclei. Interest in determining cross sections for photoneutron reactions in the threshold energy region, which is of particular importance for astrophysics, has grown substantially in recent years. The use of modern sources of quasimonoenergetic photons obtained in processes of inverse Compton laser-radiation scattering on relativistic electronsmakes it possible to reveal rather interesting special features of respective cross sections, manifestations of pygmy E1 and M1 resonances, or the production of nuclei in isomeric states, on one hand, and to revisit the problem of systematic discrepancies between data on reaction cross sections from experiments of different types, on the other hand. Data obtained on the basis of our new experimental-theoretical approach to evaluating cross sections for partial photoneutron reactions are invoked in considering these problems.

  18. The human acrosome reaction

    Institute of Scientific and Technical Information of China (English)

    H.W.G.Baker; D.Y.Liu; C.Garrett; M.Martic

    2000-01-01

    We developed tests of sperm-oocyte interaction: sperm-zona binding, zona-induced acrosome reaction, spermzona penetration and sperm-oolemma binding, using oocytes which failed to fertilise in clinical in vitro fertilization (IVF). Although oocyte defects contribute to failure of sperm oocyte interaction, rarely are all oocytes from one woman affected. Low or zero fertilization in standard IVFwas usually caused by sperm abnormalities. Poor sperm-zona pellucida binding was frequently associated with failure of standard IVF and obvious defects of sperm motility or morphology. The size and shape of the acrosome is particularly important for sperm binding to the oocyte. The proportion of acrosome intact sperm in the insemination medium was related to the IVF rate. Inducing the acrosome reaction with a calcium ionophore reduced sperm-zona binding. Blocking acrosome dispersal with an acrosin inhibitor prevented spermzona penetration. Sperm-zona penetration was even more highly related to IVF rates than was sperm-zona binding. Some patients had low or zero fertilization rates with standard IVF but normal sperm by conventional tests and normal sperm-zona binding. Few of their sperm underwent the acrosome reaction on the surface of the zona and none penetrated the zona. In contrast, fertilization and pregnancy rates were high with intracytoplasmic sperm injection. We call thiscondition defective zona pellucida induced acrosome reaction. Discovery of the nature of the abnormalities in the signal transduction and effector pathways of the human zona pellucida induced acrosome reaction should result in simpler tests and treatments for the patients and also provide new leads for contraceptive development.

  19. Les observables

    Directory of Open Access Journals (Sweden)

    Bergounioux Gabriel

    2014-07-01

    jacents ? Au cours de cette table ronde, la question des observables sera interrogée en partant d’une réflexion concernant les études qui se fondent sur l’inventaire empirique des données pour construire leurs analyses (statistique lexicale, Labphon, corpus-guided linguistics, sociolinguistique variationniste, linguistique cognitive… et en allant jusqu’aux théories qui postulent l’existence de formalismes préalables dont les discours et les textes ratifieraient, par l’actualisation et la distribution de leurs occurrences, la pertinence épistémologique.

  20. Parameters influencing the pyrotechnic reaction

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Beat [Swiss Department of Defence, Civil Protection and Sports, armasuisse, Science and Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2005-02-01

    Phenomena (reaction effects) such as varied light emissions, sound, varied burning rates, varied heats of reaction and reaction products occur during the reaction of inorganic redox systems used for pyrotechnics. The peculiarity of these redox reactions is, that they take place as solid-solid, solid-liquid or solid-gaseous state reactions. In opposite the theoretical redox reaction normally postulated in inorganic chemistry takes place in a solvent. By variation of different parameters as for example the reducing agent, the oxidizer, the oxygen balance and the particle size, it is possible to create the above-mentioned effects in a wide range. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  1. Metathetical Redox Reaction of (Diacetoxyiodoarenes and Iodoarenes

    Directory of Open Access Journals (Sweden)

    Antoine Jobin-Des Lauriers

    2015-12-01

    Full Text Available The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodoarenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy to access (diacetoxyiodoarenes. A computational study is provided to rationalize the results observed.

  2. Observación de la reacción tisular del precinto comercial de poliamida empleado como método de ligadura en pedículo renal y ute rino en conejos Observation of tissular reaction of commercial polyamide seal used as a method of bond in renal and uterine pedicle in rabbits

    Directory of Open Access Journals (Sweden)

    R Rovere

    2007-01-01

    -absorbables (polypropilene, polyester and polyamide. Staples and vascular clips can also be employed for permanent haemostasia allowing a good occlusion of the vascular pedicles, but their high cost limits their use in veterinary surgery. In this study, tissular reaction at vascular pedicle level was evaluated in rabbits after using a polyamide seal. Six male rabbits underwent nephrectomy and the pedicle was ligatured with polyamide. The remaining six animals underwent ovariohysterectomy with the placement of a seal at uterine cervix level. The haemostasia provided by the implant was immediate and safe after its application. The macroscopic and microscopic observations of the animals showed that the tissular reaction was minimal. Neither tissular necrosis nor a severe inflammation degree were observed during histophatologic studies; nor signs of infection. The polyamide commercial seal is an easy to apply, safe technique, it also causes minimal tissular reaction and has a low cost, making possible its use in vascular pedicle ligatures at surgical veterinary practices.

  3. A characterization of the two-step reaction mechanism of phenol decomposition by a Fenton reaction

    Science.gov (United States)

    Valdés, Cristian; Alzate-Morales, Jans; Osorio, Edison; Villaseñor, Jorge; Navarro-Retamal, Carlos

    2015-11-01

    Phenol is one of the worst contaminants at date, and its degradation has been a crucial task over years. Here, the decomposition process of phenol, in a Fenton reaction, is described. Using scavengers, it was observed that decomposition of phenol was mainly influenced by production of hydroxyl radicals. Experimental and theoretical activation energies (Ea) for phenol oxidation intermediates were calculated. According to these Ea, phenol decomposition is a two-step reaction mechanism mediated predominantly by hydroxyl radicals, producing a decomposition yield order given as hydroquinone > catechol > resorcinol. Furthermore, traces of reaction derived acids were detected by HPLC and GS-MS.

  4. Isovector giant resonances in sup 6 He, sup 1 sup 2 B, sup 9 sup 0 Y, sup 1 sup 2 sup 0 In, and sup 2 sup 0 sup 8 Tl observed in the ( sup 7 Li, sup 7 Be) charge-exchange reaction

    CERN Document Server

    Annakkage, T; Winfield, J S; Berg, G P A; Brown, J A; Crawley, G; Danczyk, S; Fujiwara, M; Mercer, D J; Pham, K; Roberts, D A; Stasko, J T; Yoo, G H

    1999-01-01

    The ( sup 7 Li, sup 7 Be) and ( sup 7 Li, sup 7 Be gamma) reactions have been studied at bombarding energies of 50 A MeV on targets of sup 6 Li, sup 1 sup 2 C, sup 9 sup 0 Zr, sup 1 sup 2 sup 0 Sn, sup 2 sup 0 sup 8 Pb, and polystyrene. The detection of Doppler-shifted gamma-rays from excited sup 7 Be permits the identification of the spinflip and non-spinflip characteristics. Transitions to over 20 discrete states and resonances have been observed. Angular distributions for sup 6 Li and sup 1 sup 2 C are well described by microscopic one-step distorted-waves calculations with shell-model transition amplitudes. The transitions to the ground states of sup 6 He and sup 1 sup 2 C exhibit significant Gamow-Teller strength, but approx 7% and approx 17%, respectively, of the calculated cross sections at theta approx 0 deg. arise from the tensor interaction. A broad resonance at approx 5.6 MeV in the halo nucleus sup 6 He with J suppi = (2 sup + , 1 sup - , 0 sup +) seems to correspond to a structure predicted at th...

  5. 静脉输注核黄素致新生儿局部不良反应的观察和护理体会%Observation and nursing experience on the local adverse reactions of the newborn induced by the intravenous infusion of riboflavin

    Institute of Scientific and Technical Information of China (English)

    杨妩媚

    2014-01-01

    Objective:to grasp the treatment methods for the new born after the use of the riboflavin subcutaneous fluid extravasations.Methods:to pose an individualized use of hirudoid ointment,phento lamine,and magnesium sulfate on the newborn according to the concrete situations.Results:the selected pa-tients received good Results:and no scarring.Conclusions:infusing the riboflavin sodium phosphate to the newborn is prone to the local adverse reactions.But through the active observation and reasonable care measures,the patient newborn can achieve good results.%目的:针对新生儿使用核黄素后液体皮下外渗,了解处理的方法。方法:根据具体反映情况,针对性使用喜疗妥软膏,酚妥拉明,硫酸镁等。结果:所选病例均取的良好效果,无疤痕形成。结论:新生儿输注核黄素磷酸钠容易发生局部不良反应,但通过积极的观察和合理的护理措施,都能取得良好的效果。

  6. 静脉输注核黄素致新生儿局部不良反应的观察和护理体会%Observation and nursing experience on the local adverse reactions of the newborn induced by the intravenous infusion of riboflavin

    Institute of Scientific and Technical Information of China (English)

    杨妩媚

    2014-01-01

    目的:针对新生儿使用核黄素后液体皮下外渗,了解处理的方法。方法根据具体反应情况,针对性使用多磺酸粘多糖乳膏、酚妥拉明、硫酸镁等。结果所选病例均取得良好效果,无瘢痕形成。结论新生儿输注核黄素磷酸钠容易发生局部不良反应,但通过积极的观察和合理的护理措施,都能取得良好的效果。%Objective To grasp the treatment methods for the new born after the use of the riboflavin subcutaneous fluid extravasations.Methods To pose an individualized use of hirudoid ointment, phento lamine, and magnesium sulfate on the newborn according to the concrete situations.Results The selected patients received good results and no scarring.Conclusion Infusing the riboflavin sodium phosphate to the newborn is prone to the local adverse reactions. But through the active observation and reasonable care measures, the patient newborn can achieve good results.

  7. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  8. Neutrons from Piezonuclear Reactions

    CERN Document Server

    Cardone, F; Mignani, R; Perconti, W; Petrucci, A; Rosetto, F; Spera, G

    2007-01-01

    We report the results obtained by cavitating water solutions of iron salts (iron chloride and iron nitrate) with different concentrations at different ultrasound powers. In all cases we detected a neutron radiation well higher than the background level. The neutron production is perfectly reproducible and can at some extent be controlled. These evidences for neutron emission generated by cavitation support some preliminary clues for the possibility of piezonuclear reactions (namely nuclear reactions induced by pressure and shock waves) obtained in the last ten years. We have been able for the first time to state some basic features of such a neutron emission induced by cavitation, namely: 1) a marked threshold behavior in power, energy and time; 2) its occurring without a concomitant production of gamma radiation.

  9. Nuclear reactions in astrophysics

    International Nuclear Information System (INIS)

    It is revised the nuclear reactions which present an interest in astrophysics regarding the explanation of some problems such as the relative quantity of the elements, the structure and evolution of the stars. The principal object of the study is the determination of the experimental possibilities in the field of astrophysics, of an accelerator Van de Graaff's 700 KeV type. Two hundred nuclear reactions approximately, were found, and nothing or very little has been done in the intervals of energy which are of interest. Since the bombardment energies and the involved sections are low in some cases, there are real possibilities, for the largest number of stars to obtain important statistical data with the above mentioned accelerator, taking some necessary precautions. (author)

  10. Photooxidative reactions of psoralens

    International Nuclear Information System (INIS)

    The mechanism and biological significance of photooxidative reactions of psoralens are reviewed. Skin-photosensitizing activities of bifunctional and monofunctional psoralens are compared. Antioxidants tocopherols and butilated hydroxytoluene inhibit photochemical reactions of psoralens responsible for induction of erythema. The same antioxidants do not inhibit PUVA-therapy of psriasis. Though psoralens can generate singlet oxygen under UVA-irradiation (315 - 400 nm), nevertheless singlet oxygen does not play significant role in 8-methoxypsoralen (8-MOP) sensitized photooxidation of tocopherol or dihydroxyphenylalanine (DOPA). SH-compounds enhance the rate of 8-MOP sensitized photooxidation of DOPA by a factor of four, simultaneously the rate of oxidation of SH-groups is enhanced many fold in the presence of DOPA. Under UVA-irradiation in organic solvents psoralens are photooxidized. Dimeric photooxidized psoralens are easily destructed in water medium, their destruction induce oxidation of unsaturated lipids and DOPA. (author)

  11. Two photon reactions

    International Nuclear Information System (INIS)

    Some recent results from the field of photon-photon interaction are presented. After a brief general introduction author discusses resonance production, exclusive processes with the four pion final state (γγ→π+π-π+π-), exclusive reaction γγ→psi psi, γγ - 2 body final state and jet production. Total hadronic cross sections for γγ - interactions and the photon structure function are also considered. (M.F.W.)

  12. Polymerase chain reaction

    OpenAIRE

    Gaurav Solanki

    2015-01-01

    The polymerase chain reaction (PCR) is a technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications. There are three major steps involved in the PCR technique: denaturation, annealing and extension. PCR is useful in the investigation...

  13. Photochemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

    1993-12-01

    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  14. Kinetics of interfacial reaction between uranium dioxide and zircaloy-2

    International Nuclear Information System (INIS)

    Solid state reaction between UO2 pellets and zircaloy-2 has been studied at temperature between 1270 and 1775 K. It has been observed that the reaction results in the formation of three layers. The kinetics of growth of these layers have been studied in depth and are found to obey parabolic relatjon with annealing time. The temperature dependence of the growth rate of these reaction layers obeys an Arrhenius type of relation. Micro cracks and longitudinal gaps were observed in some of the couples (towards UO2 pellet side) annealed for longer period. The presence of gaps and cracks suggests that the reaction is assisted by a process involving stress and strain in the reaction zone set up by differential contraction between uranium dioxide and reaction layers. (author)

  15. Observational exobiology

    Science.gov (United States)

    Tarter, J.

    1986-01-01

    The Earth's atmosphere absorbs partially or completely many ultraviolet, infrared and submillimeter wavelengths. Atmospheric seeing distorts small images, imposing a limit on the achievable angular resolution at optical and infrared wavelengths that is much poorer than the intrinsic capability of telescope optics. The atomic and molecular species of the atmosphere confuse or prevent the spectral studies of similar compounds outside of the terrestrial environment. Telescopes placed in orbit above the atmosphere avoid these problems and enjoy a unique view of the universe. There are many complex questions pertaining to the origin and evolution of the biogenic elements and compounds and the existence of terrestrial types of planets elsewhere that can be only tackled from orbiting facilities. The detailed nature of the spacecraft, platforms and instrumentation most likely to be launched by the United States and Europe in the near future in an attempt to determine what observational programs would be tractable and which areas of interest to exobiology required hardware capabilities beyond those currently envisioned are considered.

  16. Chemical reaction between single hydrogen atom and graphene

    International Nuclear Information System (INIS)

    We study chemical reaction between a single hydrogen atom and a graphene, which is the elemental reaction between hydrogen and graphitic carbon materials. In the present work, classical molecular dynamics simulation is used with modified Brenner's empirical bond order potential. The three reactions, that is, absorption reaction, reflection reaction and penetration reaction, are observed in our simulation. Reaction rates depend on the incident energy of the hydrogen atom and the graphene temperature. The dependence can be explained by the following mechanisms: (1) The hydrogen atom receives repulsive force by π-electrons in addition to nuclear repulsion. (2) Absorbing the hydrogen atom, the graphene transforms its structure to the 'overhand' configuration such as sp3 state. (3) The hexagonal hole of the graphene is expanded during the penetration of the hydrogen atom. (author)

  17. On "Sub-Threshold" Reactions Involving Nuclear Fission

    OpenAIRE

    Goldhaber, M.; Shrock, R.

    2000-01-01

    We analyze reactions of several types that are naively below threshold but can proceed because of the release of binding energy from nuclear fission and occasionally the formation of Coulombic bound states. These reactions include (i) photofission with pion production and (ii) charged current neutrino-nucleus reactions that lead to fission and/or formation of a Coulomb bound state of a $\\mu^-$ with the nucleus of a fission fragment. We comment on the possible experimental observation of these...

  18. Incidence and severity of anaphylactoid reactions to colloid volume substitutes.

    Science.gov (United States)

    Ring, J; Messmer, K

    1977-02-26

    All available colloid volume substitutes carry the risk of anaphylactoid reactions. In a multicentre prospective trial, 69 cases of anaphylactoid reactions have been observed among 200 906 infusions of colloid volume substitutes. The frequency of severe reactions (shock, cardiac and/or respiratory arrest) was 0-003% for plasma-protein solutions, 0-006% for hydroxyethyl starch, 0-008% for dextran, and 0-038% for gelatin solutions. PMID:65572

  19. Astrophysical Reaction Rates as a Challenge for Nuclear Reaction Theory

    OpenAIRE

    Rauscher, T.

    2010-01-01

    The relevant energy ranges for stellar nuclear reactions are introduced. Low-energy compound and direct reactions are discussed. Stellar modifications of the cross sections are presented. Implications for experiments are outlined.

  20. REACTION CHEMISTRY RELATED TO FCC GASOLINE QUALITY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    transfer reactions. All the reactions occurred in the chain termination step are reversible adsorption and desorption processes. The olefins are the products from desorption of carbenium ions. The chain mechanism of n-hexane cracking can be used to well explain the product distribution.   The cracking of n-hexane over Y and Beta zeolites shows high values of CCL. It means that bimolecular reactions of chain propagation proceed to a higher extent. Therefore, Y and Beta zeolites exhibit a higher selectivity for iso-paraffins which are the products only in chain propagation step. Whereas, a low value of CCL observed from small-pore ferrierite zeolite indicates that the monomolecular route is the main cracking pathway. Since the olefins are formed by monomole-cular reaction in chain termination, ZSM-5 and ferrierite zeolites favor the formation of olefins, and the value of CCL of these small-pore zeolites approaches the theoretical minimum value of CCL.   The values of CCL depend also on the reaction temperature, in particular the CCL of Y and Beta zeolites. Our results show that the CCL for n-hexane cracking over HY and ZSM-5 zeolites increases with the increase of reaction temperature, indicating an increasing contribution of the monomolecular reaction in the chain initiation and termination. This can be explained on the basis of the higher activation energy for monomolecular reaction as compared to that for bimolecular reaction in propagation. In addition, the apparent activation energy of the overall reaction and some elementary reactions supports the theoretical postulation of the chain mechanism of n-hexane cracking.    Catalyst design is based on the understanding of the chain mechanism of the cracking reactions and the correlation between CCL and zeolite properties. A new series of GOR catalysts, which stand for “Gasoline olefin reduction” catalysts, has been developed and commercially applied in a number of refineries. The commercial results indicate

  1. Compound-nuclear reaction cross sections via surrogate reactions

    International Nuclear Information System (INIS)

    The surrogate reaction method is an indirect technique for determining cross sections for nuclear reactions that proceed through a well-defined compound nucleus. In this method, the same compound nucleus is produced by an alternate ('surrogate') reaction and its decay products measured. The assumptions underlying the method are examined for the special case of 235U(n, f)

  2. Insect bite reactions

    Directory of Open Access Journals (Sweden)

    Sanjay Singh

    2013-01-01

    Full Text Available Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some

  3. On some microstructural aspects of concrete deterioration

    Directory of Open Access Journals (Sweden)

    Draper, E. A.

    1993-12-01

    Full Text Available There are numerous mechanisms that can lead to deterioration of portland-cement concrete in service. The best known are corrosion of reinforcement, freezing-thawing expansion, alkali-silica reaction, acid attack, and sulfate-related problems, including delayed ettringite formation. Additionally, concrete can deteriorate as a consequence of improper processing, including curing. Often, several of the above mechanisms of deterioration are jointly responsible for the observed damage. This paper briefly reviews the light-optical and electronoptical microscopic methods available to study some of the causes of concrete deterioration, and briefly describes selected case studies. Specifically, microstructural features resulting from physical (e.g., freezing-thawing and chemical (e.g., alkali-silica reaction, delayed ettringite formation deterioration of concrete are highlighted. Corrosion of reinforcement is not discussed.

    Hay numerosos procesos que pueden afectar al hormigón de cemento portland. Los más conocidos son: la corrosión de las armaduras, el efecto expansivo del hielo-deshielo, la reacción álcali-árido, el ataque ácido y los problemas que atañen a los sulfates, incluyendo la formación de ettringita expansiva. Además, el hormigón puede deteriorarse como consecuencia de determinados procesos, entre los que se cuenta el curado. A menudo, más de uno de los mecanismos citados influyen conjuntamente en el daño observado en el hormigón. El presente artículo revisa brevemente métodos de microscopía óptica y electrónica utilizados para estudiar las causas que motivaron deterioro en el hormigón, y resume algún caso seleccionado; concretamente, se destacan los efectos microestructurales que resultan de mecanismos físicos (por ejemplo, de hielo-deshielo y químicos (p.ej., reacción álcali-sílice; formación de ettringita expansiva. No se hace mención de aspectos relativos a corrosión de armaduras.

  4. Chernobyl - the government reaction

    International Nuclear Information System (INIS)

    The Farmers' Union of Wales submitted this memorandum to the Agriculture Committee of the House of Commons giving its interpretation of the Government's reaction to the Chernobyl disaster. The primary aim of the paper is to provide an objective assessment of the impact of the disaster and the Government's handling of it, for future reference. The subject is dealt with under the following headings:- Chernobyl nuclear fallout in Wales, monitoring of milk and fresh vegetables, silage contamination, the North Wales Sheep Sector, soil, herbage and genetic implications, recommendations for the future. (UK)

  5. Progress in all-order breakup reaction theories

    Indian Academy of Sciences (India)

    R Chatterjee

    2010-07-01

    Progress in breakup reaction theories, like the distorted wave Born approximation, the continuum discretized coupled channels method and the dynamical eikonal approximation, is brought into focus. The need to calculate exclusive reaction observables and the utility of benchmark tests as arbitrators of theoretical models are discussed.

  6. Adverse blood transfusion reactions at tertiary care hospital

    Directory of Open Access Journals (Sweden)

    Surekha K. Chavan

    2016-06-01

    Conclusions: Not a single case of anaphylactic reactions, TRALI, acute immune hemolytic transfusion reaction, and Sepsis was observed. This can be an underestimation of the true incidence because of under reporting which can be improved by proper hemovigilence system to provide better patient care. [Int J Res Med Sci 2016; 4(6.000: 2402-2407

  7. High stereoselectivity on low temperature Diels-Alder reactions

    Directory of Open Access Journals (Sweden)

    Invernize Paulo

    2005-12-01

    Full Text Available Abstract We have found that some of the usually poor dienophiles (2-cycloenones can undergo Diels-Alder reaction at -78°C with unusually high stereoselectivity in the presence of niobium pentachloride as a Lewis acid catalyst. A remarkable difference in reaction rates for unsubstituted and α- or β-methyl substituted 2-cycloenones was also observed.

  8. Polarization in heavy-ion reactions

    International Nuclear Information System (INIS)

    Determination of the polarization and spin alignment of reaction products emitted from heavy ion reactions should provide a sensitive test of reaction mechanisms. Techniques for producing both polarized beams and polarized targets are advancing rapidly. At the Oak Ridge National Laboraotry interest in this field has lead to the design and construction of a laser optically pumped polarized target by illuminating a supersonic gas jet. This target, which is mounted in the scattering chamber of a magnetic spectrometer, will be used to observe effects when deformed polarized targets are bombarded by heavy ions. Mutual research interests led to the invitation of Professor Fick, a pioneer in heavy ion polarization research who recently reviewed the status of this field, to Oak Ridge. While at ORNL he presented a series of lectures on this subject. Notes from these lectures are presented

  9. Oscillatory reactions on single crystal surfaces

    Science.gov (United States)

    Imbihl, R.

    1993-12-01

    Heterogeneous catalytic reactions exhibit under certain conditions kinetic oscillations which have been investigated both with polycrystalline materials and with single crystal surfaces as catalysts. The present paper reviews single-crystal experiments conducted under isothermal, low pressure conditions ( p Turing structures and the appearance of deterministic chaos, and chemical turbulence. The mechanistic steps leading to the observed phenomena have been investigated and appropriate mathematical models have been formulated and analyzed using bifurcation theory. The driving force for the rate oscillations has been shown to result from structural changes of the substrate in the case of catalytic CO oxidation on Pt surfaces, subsurface oxygen formation in the case of catalytic CO oxidation on Pd surfaces, and in the chemical reaction network described by a vacancy model in the case of the NO reduction reactions.

  10. Ubiquitous ``glassy'' relaxation in catalytic reaction networks

    Science.gov (United States)

    Awazu, Akinori; Kaneko, Kunihiko

    2009-10-01

    Study of reversible catalytic reaction networks is important not only as an issue for chemical thermodynamics but also for protocells. From extensive numerical simulations and theoretical analysis, slow relaxation dynamics to sustain nonequlibrium states are commonly observed. These dynamics show two types of salient behaviors that are reminiscent of glassy behavior: slow relaxation along with the logarithmic time dependence of the correlation function and the emergence of plateaus in the relaxation-time course. The former behavior is explained by the eigenvalue distribution of a Jacobian matrix around the equilibrium state that depends on the distribution of kinetic coefficients of reactions. The latter behavior is associated with kinetic constraints rather than metastable states and is due to the absence of catalysts for chemicals in excess and the negative correlation between two chemical species. Examples are given and generality is discussed with relevance to bottleneck-type dynamics in biochemical reactions as well.

  11. What happens actually in multinucleon transfer reactions?

    International Nuclear Information System (INIS)

    In the 90Zr+208Pb reaction at 560 MeV identical Gaussian isotopic distributions having a width of 2.5 u are observed for products of Z comprised between 40 and 32: Are they really due to a multineutron pick-up process accompanying any proton stripping, as believed today? In fact they are distributions of the neutron number N of the product around its most probable value: This uncertainty in N results from the lifetime of only 0.17 yoctosecond of a new state of nuclear matter, which has been also found in the fission reaction. Interestingly, the new state is characterized by the disappearance of any proton charge and might be triggered, in fission, by a combined shifting of the proton phase against the neutron phase of ordinary matter: It may be asked whether this state is triggered, in transfer reactions, by the crossing of the Coulomb barrier, at which any proton charge should logically disappear.

  12. Decoupling interfacial reactions between plasmas and liquids: charge transfer vs plasma neutral reactions.

    Science.gov (United States)

    Rumbach, Paul; Witzke, Megan; Sankaran, R Mohan; Go, David B

    2013-11-01

    Plasmas (gas discharges) formed at the surface of liquids can promote a complex mixture of reactions in solution. Here, we decouple two classes of reactions, those initiated by electrons (electrolysis) and those initiated by gaseous neutral species, by examining an atmospheric-pressure microplasma formed in different ambients at the surface of aqueous saline (NaCl) solutions. Electrolytic reactions between plasma electrons and aqueous ions yield an excess of hydroxide ions (OH(-)), making the solution more basic, while reactions between reactive neutral species formed in the plasma phase and the solution lead to nitrous acid (HNO2), nitric acid (HNO3), and hydrogen peroxide (H2O2), making the solution more acidic. The relative importance of either reaction path is quantified by pH measurements, and we find that it depends directly on the composition of the ambient background gas. With a background gas of oxygen or argon, electron transfer reactions yielding excess OH(-) dominate, while HNO2 and HNO3 formed in the plasma and by the dissolution of nitrogen oxide (NOx) species dominate in the case of air and nitrogen. For pure nitrogen (N2) gas, we observe a unique coupling between both reactions, where oxygen (O2) gas formed via water electrolysis reacts in the bulk of the plasma to form NOx, HNO2, and HNO3. PMID:24144120

  13. Observation of complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions: Measurement and analysis of forward recoil ranges at E/A{approx}5-6 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pushpendra P.; Kumar Sharma, Manoj; Unnati; Singh, Devendra P.; Singh, B.P.; Prasad, R. [A. M. University, Accelerator Laboratory, Department of Physics, Aligarh (India); Kumar, Rakesh; Golda, K.S. [Inter-University Accelerator Center, NP Group, P. O. Box No. 10502, New Delhi (India)

    2007-10-15

    With a view to study complete- and incomplete-fusion components in {sup 159}Tb,{sup 169}Tm({sup 16}O,x) reactions, experiments have been carried out at the Inter-University Accelerator Center, New Delhi, India using the 15UD Pelletron accelerator facilities. The forward mean recoil ranges for some radio-nuclides: {sup 168m}Lu, {sup 167}Lu, {sup 167}Yb, {sup 166}Tm produced in the {sup 16}O+{sup 159}Tb system at {approx}90 MeV, and {sup 179}Re, {sup 177}Re, {sup 177}W, {sup 178}Ta and {sup 177}Hf produced in the {sup 16}O+{sup 169}Tm system at {approx}87 MeV have been measured. The recoil-catcher activation technique followed by off-line {gamma}-spectrometry has been employed in the present work. The analysis of forward mean ranges for different radio-nuclides has been done in the framework of the degree of linear momentum transfer from projectile to target nucleus by adopting break-up fusion model considerations. Different complete- and incomplete-fusion components, which may be attributed to the fusion of {sup 16}O and/or {sup 12}C and {sup 8}Be transfer from the {sup 16}O projectile to the target nucleus have been observed. An attempt has also been made to separate out the relative percentage contributions of complete- and incomplete-fusion components using experimentally measured forward recoil ranges. The complete-fusion contributions deduced from recoil range distribution are found to be consistent with the prediction of the theoretical model code PACE. The analysis of data indicates the complete- and incomplete-fusion competition for both the systems at the given energies. (orig.)

  14. (d,pγ) Reactions and the surrogate reaction technique

    International Nuclear Information System (INIS)

    Neutron-capture reactions on neutron-rich nuclei are important to understand r-process nucleosynthesis, as well as applied needs such as stewardship science and nuclear energy. Because of the short half-lives of these species, it is not possible to measure these reactions directly with neutron beams on unstable targets. The (d,pγ) reaction with radioactive ion beams has been proposed as a surrogate reaction for (n,γ). Experiments to develop (d,pγ) techniques with radioactive ion beams and to demonstrate the efficacy of the (d,pγ) reaction as a surrogate for (n,γ) are discussed

  15. Zeolite Catalyzed Aldol Condensation Reactions

    OpenAIRE

    Adedayo I. Inegbenebor; Raphael C. Mordi; Oluwakayode M. Ogunwole

    2015-01-01

    The review is based on the description of zeolite structure, uses, synthesis, and catalytic aldol reaction in aldol condensation. An internal aldolcondensation reaction has been achieved over ZSM-5 zeolite with high silica-alumina ratio at 350oC. It therefore follows that zeolite canfunction as a catalyst in aldol type condensation reactions and that weak acid sites as well as a small number of active sites favor the aldolcondensation reaction of carbonyl compounds. However, the mixed condens...

  16. Reaction spreading on percolating clusters

    OpenAIRE

    Bianco, Federico; Chibbaro, Sergio; Vergni, Davide; Vulpiani, Angelo

    2013-01-01

    Reaction-diffusion processes in two-dimensional percolating structures are investigated. Two different problems are addressed: reaction spreading on a percolating cluster and front propagation through a percolating channel. For reaction spreading, numerical data and analytical estimates show a power-law behavior of the reaction product as M(t) \\sim t^dl, where dl is the connectivity dimension. In a percolating channel, a statistically stationary traveling wave develops. The speed and the widt...

  17. Hydrogen isotope exchange reactions

    International Nuclear Information System (INIS)

    The two most widely used methods for following hydrogen isotope exchange reactions, namely dedeuteriation and detritiation, involve in the first place the synthesis of an appropriately labelled compound. Rates of dedeuteriation are usually followed by measuring changes in the 1H n.m.r. spectrum of the substrate (examples are given); the method not only gives the rate but also the site(s) of exchange. It is limited to rather slow reactions and is not as accurate as some of the other methods. The development of deuterium n.m.r. spectroscopy means that changes in the 2H n.m.r. spectrum can also be used to measure rates of dedeuteriation. The development of liquid scintillation counting greatly eased the problem of how to detect weak β emitters; the attractions of tritium as a tracer were thereby much enhanced. Nowadays the study of rates of detritiation constitutes one of the most versatile and accurate methods of following hydrogen isotope exchange. Examples of the technique are given. (U.K.)

  18. Status of breakup reaction theory

    International Nuclear Information System (INIS)

    Recent studies on breakup reactions with the continuum-discretized coupled-channels method are reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, dynamical relativistic effects on Coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple-α reaction rate) and new approach to inclusive breakup processes.

  19. Medications and Drug Allergic Reactions

    Science.gov (United States)

    ... breathing. This is most common in adults with asthma and in people with nasal polyps (benign growths). Other reactions to NSAIDs can result in hives or in rare instances, severe reactions can result in shock. A number of factors influence your chances of having an adverse reaction ...

  20. The power-law reaction rate coefficient for barrierless reactions

    International Nuclear Information System (INIS)

    We study the power-law reaction rate coefficient for barrierless reactions, when the reactions take place in systems with power-law distributions, and derive a generalized rate formula for the barrierless reactions in the Gorin model. We show that, unlike those for bimolecular and unimolcular reactions, due to the lack of barriers, the power-law rate coefficient for barrierless reactions does not have a power-law function, and thus is not very strongly dependent on the ν-parameter. Four barrierless reactions are taken as application examples to calculate the new rate coefficients, which with larger fitting ν-parameters can be exactly in agreement with measurements in the experimental studies. (paper)

  1. Particle densities in ultrarelativistic heavy ion reactions extrapolated from proton-nucleus collisions

    International Nuclear Information System (INIS)

    Rapidity density distributions in central ultra-relativistic heavy ion reactions are estimated from high energy proton-nucleus collisions and compared with some cosmic ray events. Deviations from a simple scaling of pA reactions are observed. (author)

  2. Linear free energy relationship in reactions between diphenyl amine and benzyl bromides

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2006-05-01

    Rate of reaction between benzyl bromide and diphenyl amine is retarded by electron-donating groups and enhanced by electron-withdrawing groups present on the benzene ring of the substrate. Hammett's reaction constant of the reaction decreases with increase in temperature according to the equation, \\rho = -11.92 + 3.54/ T. Minimal structural effects observed are attributed to the fact that the isokinetic temperature of the reaction is close to the reaction temperature.

  3. Recyclable hydrotalcite clay catalysed Baylis-Hillman reaction

    Indian Academy of Sciences (India)

    Vivek Srivastava

    2013-09-01

    The Baylis-Hillman reaction using ionic liquid/hydrotalcite clay catalytic system has been observed to be more reactive in terms of yield and reaction rate than DABCO/acetonitrile system. During the process, the reactants enjoy ionic liquid/hydrotalcite clay catalytic system and gives corresponding Baylis-Hillman reaction products in good yield. The application of our catalytic system has been diversifying for the synthesis of lactone ceramide analogue from (S)-Garner aldehyde-methyl acrylate using Baylis-Hillman reaction. Recycling of ionic liquid/hydrotalcite clay catalytic system has also been demonstrated in this report.

  4. The Influence Factors of the BZ Oscillating Reaction

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ As a typical oscillating chemical reaction, studies of the Belousov-Zhabotinsky reaction have not only yielded important results to provide insights to many kinetic and thermodynamic problems, but also provided suggestive models for a number of important biological processes. Now the BZ reaction has become a useful experimental model for studying nonlinear phenomena in distributed systems. We carried out a systematic study of the influence factors on the BZ reaction in a closed system, and some new observations are reported here forthe first time.

  5. The Influence Factors of the BZ Oscillating Reaction

    Institute of Scientific and Technical Information of China (English)

    LIU; XiuHui

    2001-01-01

    As a typical oscillating chemical reaction, studies of the Belousov-Zhabotinsky reaction have not only yielded important results to provide insights to many kinetic and thermodynamic problems, but also provided suggestive models for a number of important biological processes. Now the BZ reaction has become a useful experimental model for studying nonlinear phenomena in distributed systems. We carried out a systematic study of the influence factors on the BZ reaction in a closed system, and some new observations are reported here forthe first time.  ……

  6. The reaction of uranium with moist hydrogen

    International Nuclear Information System (INIS)

    The reaction of uranium in moist hydrogen at a total pressure of 101 kPa over the temperature range 1050-2000C and water vapour pressures in the range 5-100 kPa has been examined in a limited thermogravimetric study. It has been shown that initially there is a period during which only linear kinetics are observed with a rate similar to that exhibited in similarly moist argon, i.e. hydrogen has no apparent effect on the reaction. At water vapour pressures of and above 49 kPa, corresponding to hydrogen:water vapour pressure ratios in the range 1:1 to 1:100, over the exposure times studied (not > 20h) only such linear kinetics are observed. Below this water vapour pressure and after an initial period of linear kinetics a continuously increasing reaction rate was observed in some instances resulting from rapid attach on localised areas. The localised reaction rates were approximately 2-3 orders of magnitude faster than the original linear reaction kinetics and the interaction rates in either moist argon or moist air. Comparison with a single experiment carried out at 1500C indicated that breakaway rates were approaching that in dry hydrogen. During breakaway attack there was a significant increase in the relative amounts of uranium hydride formed. The duration of the linear kinetics phase was extended by pre-oxidation of the uranium surface, decreasing temperature at a constant water vapour pressure, or increasing water vapour pressure (or water vapour: hydrogen pressure ratio) at a constant temperature. (author)

  7. The effect of catalyst support on the RWGS reaction

    International Nuclear Information System (INIS)

    'Full text:' Methane steam reforming is generally applied in order to produce synthesis gas mainly consist of hydrogen and carbon monoxide for later utilization in SOFC. This reaction is always carried out with the water gas shift reaction over a catalyst at elevated temperatures resulting in some carbon dioxide production. The CO/CO2 production selectivity strongly depends on the influence of water gas shift reaction. It was observed that the reactivity of this reaction depended on the type of support material. Stabilities, activities, and kinetics of the reverse water gas shift reaction (RWGS) for commercial nickel on CeO2, ZrO2, CeO2-ZrO2, TiO2, MgO, and Al2O3 supports were studied in order to observe the influence of the support on this reaction. According to the experiment, the activities of Ni/CeO2 toward the reverse water gas shift reaction (RWGS) were very high, and reached equilibrium level at approximately 600oC (where the conversion of CO2 was closed to 1). Other oxide supports provided lower activities toward this reaction. It was observed that the activity of Ni/Al2O3 toward this reaction was the lowest. The kinetics of this reaction was also studied. Carbon dioxide presented positive effect on the reverse water gas shift reaction. The reaction orders in carbon dioxide were observed to be positive partial value between 0-1. It slightly decreased with increasing temperature for Ni/ CeO2 and Ni/CeO2-ZrO2, whereas it seemed to be independent of the operating temperature for other materials in the range of conditions studied. Hydrogen also showed positive effect on the reverse water gas shift reaction for all materials. The reaction order in hydrogen for all materials was observed to be the positive value and less than one for the range of conditions studied. The approximate values for all catalysts were between 0.45-0.65, and seemed to be independent of the operating temperature. The estimated values of the apparent activation energy for RWGS reaction

  8. ASR potential of quartz based on expansion values and microscopic characteristics of mortar bars

    Science.gov (United States)

    Stastna, Aneta; Sachlova, Sarka; Kuchynova, Marketa; Pertold, Zdenek; Prikryl, Richard

    2016-04-01

    The alkali-silica reaction (ASR) is one of the most damaging factors for concrete structures. Different analytical techniques are used to quantify ASR potential of aggregates. The accelerated mortar bar test (ASTM C1260) in combination with the petrographic examination of aggregates by microscopic techniques belongs to the frequently employed methods. Such a methodical approach enables quantification of the ASR potential, based on the expansion values of accelerated mortar bars; and also to identify deleterious components in aggregates. In this study, the accelerated mortar bar test (ASTM C1260) was modified and combined with the scanning electron microscopy of polished sections prepared from mortar bars. The standard 14-day test period of mortar bars was prolonged to 1-year. ASR potential of aggregates was assessed based on expansion values (both 14-day and 1-year) of mortar bars and microscopic analysis of ASR products (alkali silica gels, microcracks, dissolution gaps) detected in the sections. Different varieties of quartz-rich rocks including chert, quartz meta-greywacke, three types of quartzite and pegmatite were used as aggregate. Only quartz from pegmatite was assessed to be non reactive (14-day expansion of 0.08%, 1-year expansion of 1.25%). Aggregate sections exhibited minor ASR products even after 1-year of mortar bar immersion in 1 M NaOH. Expansion values of the rest of samples exceeded the limit of 0.10% after 14-day test period indicating aggregates as reactive. The highest ASR potential was detected in mortar bars containing chert (14-day expansion of 0.55%, 1-year expansion of 2.70%) and quartz meta-greywacke (14-day expansion of 0.46%, 1-year expansion of 2.41%). The high ASR potential was explained by presence of cryptocrystalline matrix in significant volumes (24 - 65 vol%). Influence of the lengths of the immersion in the alkaline solution was observed mainly in the microstructure of the cement paste and on the extension of ASR products. The

  9. Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2012-10-01

    Full Text Available The polymerase chain reaction (PCR is a technique in molecular biology to amplify a single or a few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence. PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications. There are three major steps involved in the PCR technique: denaturation, annealing and extension. PCR is useful in the investigation and diagnosis of a growing number of diseases. PCR is also used in forensics laboratories. PCR can identify genes that have been implicated in the development of cancer. The present paper is an attempt to review basics of PCR in relation to its methods, application and use.

  10. Kinetics of Bio-Reactions

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions. The...... models can be used in mass balances for design of processes under process conditions not yet studied experimentally. The value of the predictive kinetic model depends on the quality of the experimental data on which the model is based, and well-founded kinetic models for enzyme reactions have a...... considerable predictive power. This is also true for cell reaction models, when the model is used in its proper context. The chapter first discusses the kinetics for enzymatically catalyzed reactions (“enzyme reactions”). The kinetics can be derived from a mechanistic model. Then, the chapter derives empirical...

  11. The hunt for the dynamical resonances in chemical reaction dynamics: a perspective on historical advances

    Directory of Open Access Journals (Sweden)

    Yu Angyang

    2015-06-01

    Full Text Available The theoretical background and basic definition of the resonances in chemical reaction dynamics have been introduced in this article. The historical breakthrough in the experimental search for the reaction resonances has been reviewed in this report, with an emphasis on the crossed molecular beam apparatus. The research of the chemical reaction resonances has attracted many scientists’ attention from 80s of last century. The chemical reaction resonances in the F+H2 reaction were firstly observed by the researchers of the Chinese Academy of Sciences in 2006. Besides, the partial wave resonances in the chemical reactions have been observed for the first time in 2010.

  12. The role of van der Waals interactions in chemical reactions

    International Nuclear Information System (INIS)

    We are studying the role of van der Waals interactions in the chemical reactions from the theoretical view point, especially, a case related to the tunnel effect. The fist case that the cumulative reaction probability depends on the tunnel effect was increased by the van der waals force. This case was proved by theoretical calculation of the reaction rate constant of the reaction: Mu + F2 → MuF + F. The second case was that a van der Waals well was so deep that pseudo bound state was observed in the reaction: F + H2 → HF + H. A van der Waals complex such as AB(v=j=0)...C was excited to the resonance state of AB(vij)...C and A...BC(v,j) by laser, than the resonance state proceeded to AB + C (predissociation) or A + BC(pre-reaction). We succeeded for the first time to calculate theoretically the pre-reaction by the real three dimentional potential curve. The pre-reaction can be observed only the case that the tunnel probability is larger than the non-adiabatic transition probability. The chemical reactions in solid were explained, too. (S.Y.)

  13. 右美托咪啶用于预防经尿道前列腺电切术中寒战反应的临床观察%Clinical observation of dexmedetomidine for the prevention of shivering reaction in transurethral resection of the prostate

    Institute of Scientific and Technical Information of China (English)

    靳红绪; 魏兰双; 王立红; 徐志杰; 张同军; 孙学飞; 王福朝; 王忠义

    2014-01-01

    Objectives To investigate the effect of dexmedetomidine for the prevention of shivering reaction in transurethral resection of the prostate(TURP).Methods A total of 120 patients undergoing selective TURP,aged 56 to 82 years,ASA grade Ⅰ or Ⅱ,were randomly divided into two groups with 60 cases each.After combined spinal epidural anesthesia,group D received intravenous infusion of dexmedetomidine at the dose of 3 μg · (kg · h)-1 within 10 min and then 0.4μg · (kg · h)-1 until 30 min before the end of operation.Group C received intravenous infusion of equal volume of normal saline with same way.Changes of heart rate(HR),mean arterial pressure (MAP),respiratory rate(RR),pulse oxygen saturation(Sp02) and occurrence rate and degree of shivering at each point were observed and recorded.Results There were no significant differences of hemodynamic and respiratory parameters at any time point between the two groups (P > 0.05).The rate of shivering occurrence and scores of shivering in group D were significantly lower than those of group C (P < 0.05).Conclusions Dexmedetomidine is deemed as safe,reliable and feasible to prevent the shivering reaction in TURP.%目的 观察右美托咪啶用于预防经尿道前列腺电切术(TURP)中患者发生寒战反应的效果.方法 择期拟行TURP的患者120例,年龄56~ 82岁,ASA分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为2组,每组60例.腰硬联合麻醉后D组采用静脉泵注右美托咪啶3μg·(kg·h)-1,10 min后调整输注速度为0.4μg·(kg·h)-1,术毕前30 min停止输注.C组则按相同方法泵注等量生理盐水.观察并记录两组患者泵注药物前及泵注后各时点心率(HR)、平均动脉压(MAP)、呼吸频率(RR)、血氧饱和度(SpO2)的变化;并观察寒战发生率和寒战程度分级等情况.结果 两组患者术中血流动力学及呼吸均保持平稳,比较差异无统计学意义(P>0.05);D组寒战反应发生率及寒战程

  14. Crossed molecular beam studies of unimolecular reaction dynamics

    International Nuclear Information System (INIS)

    The study of seven radical-molecule reactions using the crossed molecular beam technique with supersonic nozzle beams is reported. Product angular and velocity distributions were obtained and compared with statistical calculations in order to identify dynamical features of the reactions. In the reaction of chlorine and fluorine atoms with vinyl bromide, the product energy distributions are found to deviate from predictions of the statistical model. A similar effect is observed in the reaction of chlorine atoms with 1, 2 and 3-bromopropene. The reaction of oxygen atoms with ICl and CF3I has been used to obtain an improved value of the IO bond energy, 55.0 +- 2.0 kcal mol-1. In all reactions studied, the product energy and angular distributions are found to be coupled, and this is attributed to a kinematic effect of the conservation of angular momentum

  15. Surface reactions of tellurium on steel and zircaloy 4

    International Nuclear Information System (INIS)

    The reaction between tellurium vapours and 316 stainless steel and zircaloy 4 surfaces has been studied in the temperature range of 823-1223 K and 923-1273 K respectively. The reaction product, thickness and the intergranular attack penetration was measured for the reaction of tellurium in 316 stainless steel. In the case of zircaloy 4 reaction product was brittle and scooped out. Hence the thickness of the individual bands could not be measured. It was observed that the reaction of tellurium on 316 stainless steel and zircaloy 4 resulted in the formation of two bands in both the cases. In the case of 316 stainless steel-tellurium reaction, the outer band was rich in iron and nickel while the inner band was rich in chromium, whereas in the case of zircaloy 4-tellurium, the outer band was rich in zirconium and the inner band contained tin in addition to zirconium. Tellurium was found in both the bands. (auth.)

  16. Energy dependence of fission observables

    Science.gov (United States)

    Paşca, Horia

    2016-01-01

    The mass, charge and isotopic distributions of fission fragments are studied within an improved scission-point statistical model in the reaction 235U+n at different energies of the incident neutron. The available experimental data are well reproduced and the energy-dependencies of the observable characteristics of fission are predicted for future experiments. The calculated mass distribution of 238U+n is also compared with experimental data.

  17. Reaction-diffusion fronts under stochastic advection

    CERN Document Server

    Martí, A C; Sancho, J M

    1997-01-01

    We study front propagation in stirred media using a simplified modelization of the turbulent flow. Computer simulations reveal the existence of the two limiting propagation modes observed in recent experiments with liquid phase isothermal reactions. These two modes respectively correspond to a wrinkled although sharp propagating interface and to a broadened one. Specific laws relative to the enhancement of the front velocity in each regime are confirmed by our simulations.

  18. Progress Towards a Positron Reaction Microscope

    OpenAIRE

    Williams, A. I.; Kover, A.; Murtagh, D. J.; Laricchia, G

    2010-01-01

    The progress toward the construction of a positron reaction microscope is outlined. The design principles of an electrostatic lens system used to focus and transport the positron beam with a similar to 1 mm diameter spot are briefly discussed. Also presented here are the results obtained from the characterisation of the supersonic gas jet assembly, an increased peaking factor of similar to 4 has been observed along with a centerline density of 10(12) cm(-3).

  19. Photocatalytic reaction on photofuel cell titania electrode

    OpenAIRE

    Nishikiori, Hiromasa; Kato, Yotaro

    2012-01-01

    Benzoic acid-doped titania electrodes were prepared from titanium alkoxide sols containing benzoic acid in order to examine the photocatalytic reaction of the fuel material concentrated on the titania surface of a photofuel cell electrode. This doping was developed in order to understand the physicochemical processes on the titania rather than to advance the practical use of the photofuel cells. The observed photocurrent and CO(2) and H(2)O productions indicated that the oxidation of the benz...

  20. Ubiquitous "glassy" relaxation in catalytic reaction networks

    OpenAIRE

    Awazu, Akinori; Kaneko, Kunihiko

    2009-01-01

    Study of reversible catalytic reaction networks is important not only as an issue for chemical thermodynamics but also for protocells. From extensive numerical simulations and theoretical analysis, slow relaxation dynamics to sustain nonequlibrium states are commonly observed. These dynamics show two types of salient behaviors that are reminiscent of glassy behavior: slow relaxation along with the logarithmic time dependence of the correlation function and the emergence of plateaus in the rel...

  1. Fusion reaction product diagnostics in ASDEX

    International Nuclear Information System (INIS)

    A diagnostic method was developed to look for the charged fusion products from the D(D,p)T-reactions in the divertor tokamak ASDEX. With a semi-conductor detector it was possible to evaluate the ion temperature in thermal plasmas from the proton energy spectra as well as from the triton spectra. In lower-hybrid wave heated plasmas non-thermal (fast) ions were observed. These ions create fusion products with a characteristically different energy spectrum. (orig.)

  2. Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution

    International Nuclear Information System (INIS)

    Highlights: ► Gasification of sugarcane bagasse has been investigated using a semi batch reactor. ► Global reaction mechanism combining pyrolysis and gasification reactions is presented. ► High flow rates of syngas supported fragmentation and secondary reactions. ► CO flow rate increased at higher heating rates at the expense of CO2 production. ► At high temperatures merger between pyrolysis and char gasification occurs. -- Abstract: Steam gasification of sugarcane bagasse has been investigated. A semi batch reactor with a fixed amount of sugarcane bagasse sample placed in steady flow of high temperature steam at atmospheric pressure has been used. The gasification of bagasse was examined at reactor and steam temperatures of 800, 900 and 1000 °C. The evolution of syngas flow rate and chemical composition has been monitored. The evolution of chemical composition and total flow rate of the syngas has been used to formulate a global reaction mechanism. The mechanism combines pyrolysis reaction mechanisms from the literature and steam gasification/reforming reactions. Steam gasification steps include steam–hydrocarbons reforming, char gasification and water gas shift reactions. Evidence of fragmentation, secondary ring opening reactions and tertiary reactions resulting in formation of gaseous hydrocarbons is supported by higher flow rates of syngas and hydrogen at high heating rates and high reactor temperatures. Increase in carbon monoxide flow rate at the expense of carbon dioxide flow rate with the increase in reactor temperature has been observed. This increase in the ratio of CO/CO2 flow rate confirms the production of CO and CO2 from the competing reaction routes. At 1000 °C gasification a total merging between the pyrolysis step and the char gasification step has been observed. This is attributed to acceleration of char gasification reactions and acceleration of steam–hydrocarbons reforming reactions. These hydrocarbons are the precursors to char

  3. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    OpenAIRE

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is viola...

  4. Transient ion ejection during nanocomposite thermite reactions

    Science.gov (United States)

    Zhou, Lei; Piekiel, Nicholas; Chowdhury, Snehaunshu; Lee, Donggeun; Zachariah, Michael R.

    2009-10-01

    We observe an intense ion pulse from nanocomposite thermite reactions, which we temporally probe using a recently developed temperature jump/time of flight mass spectrometer. These ion pulses are observed to be much shorter in duration than the overall thermite reaction time. Ion ejection appears in stages as positive ions are ejected prior to nanocomposite thermite ignition, and ignition of the thermite mixtures leads to a second ionization step which is primarily dominated by negative species. The positive species are identified from mass spectrometric measurements and the results show that the positive ion species are comprised of Na ions with minor species of Al and K ions. This observation can be explained by a diffusion based ion-current mechanism, in which strong Al ion diffusion flux formed through the oxide shell, and the surface Na and K ions from salt contaminations are ejected by the strong electrostatic repulsion. The fact that the negative ionization step occurs during the ignition event suggests a strong relation between the nanocomposite thermite reaction and the negative ionization process.

  5. Resonance Reaction in Diffusion-Influenced Bimolecular Reactions

    CERN Document Server

    Kolb, Jakob J; Dzubiella, Joachim

    2016-01-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new resonant reaction behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  6. Communication: Resonance reaction in diffusion-influenced bimolecular reactions

    Science.gov (United States)

    Kolb, Jakob J.; Angioletti-Uberti, Stefano; Dzubiella, Joachim

    2016-02-01

    We investigate the influence of a stochastically fluctuating step-barrier potential on bimolecular reaction rates by exact analytical theory and stochastic simulations. We demonstrate that the system exhibits a new "resonant reaction" behavior with rate enhancement if an appropriately defined fluctuation decay length is of the order of the system size. Importantly, we find that in the proximity of resonance, the standard reciprocal additivity law for diffusion and surface reaction rates is violated due to the dynamical coupling of multiple kinetic processes. Together, these findings may have important repercussions on the correct interpretation of various kinetic reaction problems in complex systems, as, e.g., in biomolecular association or catalysis.

  7. Global observations of formaldehyde

    Science.gov (United States)

    Wittrock, F.; Richter, A.; Heckel, A.; Tarsu, M.; Burrows, J. P.

    Formaldehyde (HCHO) indicates and supports photochemical activity in the atmosphere. Large amounts are expected to found in industrial areas and during biomass burning. HCHO is a major intermediate in the degradation of methane (and many other hydrocarbons). In the absence of heterogenous losses, essentially every methane molecule is converted to HCHO. Therefore it is found throughout the troposphere. It is destroyed via photolysis and reaction with OH. In continental boundary layers, non-methane hydrocarbons (NMHCs) emitted by biogenic and anthropogenic sources dominate over Methane also as a source of HCHO. GOME is the first instrument, that allows observations of Formaldehyde on a global scale giving the opportunity to improve our knowledge about emission fluxes of Methane and NMHCs. This study presents GOME observations of formaldehyde since launch of ERS-2 in 1995. Ground-based measurements are used to validate the GOME HCHO product. In addition time series for selected regions are shown to illustrate the general interannual and interseasonal variation of HCHO depending on the main sources.

  8. clinic observation of compound recombinant human interleukin-11 solution in prevention and treatment of radiotherapy-induced oral mucositis reaction in patients with nasopharyngeal carcinoma%重组人白介素-11在防治鼻咽癌放射性口腔粘膜炎的疗效观察

    Institute of Scientific and Technical Information of China (English)

    蓝余钒; 张绪慧; 汤新跃

    2015-01-01

    Objective To observe the efficacy of recombinant human interleukin-11 ( IL-11) in treatment of oral mucositis related with nasopharyngeal carcinoma(NPC) radiotherapy.Methods 58 cases (from Mar 2013 to Dec 2014) with NPC were randomly divided into the observation group (recombinant human interleukin -11 group n = 30) and the control group (nomal saline group n = 28) . The patients were given conventional treatment if oral mucositis grade were II –IV.Results 1.The incidences of grade I were 46.7% , 3.60% and the incidences of grade III were 16.7%, 42.8% in the observation group and control group respectively(P < 0. 05) .2. in the observation group, the rate of radioactive mucositis at 20Gy and 30Gy was 33.3% and 63.4% respectively, which in the control group was 78.5% and 21.5% respectively(P < 0. 05). 3. The median time of occurrence on radiation mucositis in the observation group and in the control group was 18 and 11days respectively (P < 0. 05). 4. The mean time for radioactive oral mucositis of grade III lasting in the observation group and in the control group was 8.2 and 11.4 days respectively(P < 0. 05).Conclusions Compound recombinant human interleukin-11 solution is effective to prevent and treat the radiotherapy - induced oral mucositis reaction. It has no side effects. So it is valuable for clinical application.%目的:观察重组人白介素-11( IL-11)在防治鼻咽癌放射治疗相关性口腔粘膜炎的疗效。方法选取2013年3月~2014年12月在我院肿瘤科就诊的鼻咽癌患者58例,随机分为重组人白介素-11组(n=30)及生理盐水组(n=28),从放疗第一天开始至放疗,当两组患者出现II级及以上口腔粘膜炎时予常规对症处理。观察两组黏膜炎发生率,发生时间,反应程度及不了反应等。结果1.重组人白介素-11组和对照组I级与III级粘膜炎发生率分别为46.7%和3.60%,16.7%和42.8%(P<0.05);2.在照射剂量达20Gy及30Gy时,白介素-11组口腔

  9. [Electromagnetic studies of nuclear structure and reactions

    International Nuclear Information System (INIS)

    The experimental goals are focused on developing an understanding of strong interactions and the structure of hadronic systems by determination of the electromagnetic response; these goals will be accomplished through coincidence detection of final states. Nuclear modeling objectives are to organize and interpret the data through a consistent description of a broad spectrum of reaction observables; calculations are performed in a nonrelativistic diagrammatic framework as well as a relativistic QHD approach. Work is described according to the following arrangement: direct knockout reactions (completion of 16O(e,e'p), 12C(e,e'pp) progress, large acceptance detector physics simulations), giant resonance studies (intermediate-energy experiments with solid-state detectors, the third response function in 12C(e,e'p0) and 16O(e,e'p0), comparison of the 12C(e, e'p0) and 16O(e,e'p3) reactions, quadrupole strength in the 16O(e,e'α0) reaction, quadrupole strength in the 12C(e,e'α) reaction, analysis of the 12C(e,e'p1) and 16O(e,e'p3) angular distributions, analysis of the 40Ca(e,e'x) reaction at low q, analysis of the higher-q 12C(e,e'x) data from Bates), models of nuclear structure (experimental work, Hartree-Fock calculations, phonon excitations in spherical nuclei, shell model calculations, variational methods for relativistic fields), and instrumentation development efforts (developments at CEBAF, CLAS contracts, BLAST developments)

  10. The Effectiveness of High Quality Supplementary Cementitious Materials for Mitigating ASR Expansion in Concrete with High Alkali Content

    Directory of Open Access Journals (Sweden)

    I. Prasetia

    2015-10-01

    Full Text Available Alkali silica reaction (ASR is influenced by external factors such as the surrounding environment of high alkalinity. Countries with cold climate have a high probability to be exposed to high concentrations of NaCl solution by the deicing salt. This condition will lead to serious ASR problems in concrete, if the aggregates contain reactive silica. The main research work in this paper is to investigate the effect of 15% replacement ratio of high quality fine fly ash (FA15% and 42% replacement ratio of blast furnace slag (BFS42% on the ASR mitigation in concrete with different alkali amount inside the pore solution. The experiments were conducted according to the accelerated mortar bars experiment following the JIS A1146 mortar bar test method. In addition, post-analysis such as observation of ASR gel formation by the Uranyl Acetate Fluorescence Method and observation of thin sections using a Polarizing Microscope were also conducted. The mortar bar tests show a very good mitigation effect of supplementary cementitious materials (SCMs. The results show that only small ASR expansions, which can be categorized as “innocuous”, occurred for specimens with 1.2% Na2Oeq using FA15% and BFS42%. However, larger alkali amount inside the system will require more SCMs amount.

  11. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  12. Limits for Stochastic Reaction Networks

    DEFF Research Database (Denmark)

    Cappelletti, Daniele

    Reaction systems have been introduced in the 70s to model biochemical systems. Nowadays their range of applications has increased and they are fruitfully used in dierent elds. The concept is simple: some chemical species react, the set of chemical reactions form a graph and a rate function is...... associated with each reaction. Such functions describe the speed of the dierent reactions, or their propensities. Two modelling regimes are then available: the evolution of the dierent species concentrations can be deterministically modelled through a system of ODE, while the counts of the dierent species at...... a certain time are stochastically modelled by means of a continuous-time Markov chain. Our work concerns primarily stochastic reaction systems, and their asymptotic properties. In Paper I, we consider a reaction system with intermediate species, i.e. species that are produced and fast degraded along...

  13. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  14. The Paterno-Buchi reaction

    DEFF Research Database (Denmark)

    Brogaard, Rasmus Yding; Schalk, Oliver; Boguslavskiy, Andrey E.;

    2012-01-01

    The Paternò-Büchi (PB) reaction between an excited carbonyl compound and an alkene has been widely studied, but so far little is known about the excited-state dynamics of the reaction. In this investigation, we used a compound in which a formyl and a vinyl group are attached to a [2.......2]paracyclophane in order to obtain a model system in pre-reactive conformation for the PB reaction. We studied the excited-state dynamics of the isolated molecule in a molecular beam using femtosecond time-resolved photoelectron spectroscopy and ab initio calculations. The results show that inter-system crossing...... within two picoseconds competes efficiently with the reaction in the singlet manifold. Thus, the PB reaction in this model system takes place in the triplet state on a time scale of nanoseconds. This result stresses the importance of triplet states in the excited-state pathway of the PB reaction...

  15. Nuclear astrophysics from direct reactions

    OpenAIRE

    2008-01-01

    Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation.

  16. Piezonuclear reactions - do they exist?

    CERN Document Server

    Ericsson, G; Sjöstrand, H; Traneus, E

    2009-01-01

    In a number of recent articles in this journal F. Cardone and collaborators have claimed the observation of several striking nuclear phenomena which they attribute to "piezonuclear reactions". One such claim [Phys. Lett. A 373 (2009) 1956] is that subjecting a solution of 228Th to cavitation leads to a "transformation" of thorium nuclei that is 104 times faster than the normal nuclear decay for this isotope. In a "Comment" [Phys. Lett. A 373 (2009) 3795] to the thorium work, we have criticized the evidence provided for this claim. In a "Reply" [Phys. Lett. A 373 (2009) 3797] Cardone et al. answer only some minor points but avoid addressing the real issue. The information provided in their Reply displays a worrying lack of control of their experimental situation and the data they put forward as evidence for their claims. We point out several shortcomings and errors in the described experimental preparations, set-up and reporting, as well as in the data analysis. We conclude that the evidence presented by Cardo...

  17. Glycation Reactions of Casein Micelles.

    Science.gov (United States)

    Moeckel, Ulrike; Duerasch, Anja; Weiz, Alexander; Ruck, Michael; Henle, Thomas

    2016-04-13

    After suspensions of micellar casein or nonmicellar sodium caseinate had been heated, respectively, in the presence and absence of glucose for 0-4 h at 100 °C, glycation compounds were quantitated. The formation of Amadori products as indicators for the "early" Maillard reaction were in the same range for both micellar and nonmicellar caseins, indicating that reactive amino acid side chains within the micelles are accessible for glucose in a comparable way as in nonmicellar casein. Significant differences, however, were observed concerning the formation of the advanced glycation end products (AGEs), namely, N(ε)-carboxymethyllysine (CML), pyrraline, pentosidine, and glyoxal-lysine dimer (GOLD). CML could be observerd in higher amounts in nonmicellar casein, whereas in the micelles the pyrraline formation was increased. Pentosidine and GOLD were formed in comparable amounts. Furthermore, the extent of protein cross-linking was significantly higher in the glycated casein micelles than in the nonmicellar casein samples. Dynamic light scattering and scanning electron microscopy showed that glycation has no influence on the size of the casein micelles, indicating that cross-linking occurs only in the interior of the micelles, but altered the surface morphology. Studies on glycation and nonenzymatic cross-linking can contribute to the understanding of the structure of casein micelles. PMID:27018258

  18. Influences of Reaction Parameters on the Product of a Geothermite Reaction: A Multi-Component Oxidation-Reduction Reaction Study

    OpenAIRE

    Faierson, Eric J.

    2009-01-01

    This study investigated an oxidation-reduction reaction involving a mixture of minerals, glass, and aluminum that exhibited thermite-type reaction behavior. Thermite reactions are a class of Self-propagating High-temperature Synthesis (SHS) reactions. Chemical reactions between raw minerals and a reducing agent, which exhibit thermite-type reaction behavior, are termed geothermite reactions by the author. Geothermite reactions have the potential for use in In-Situ Resource Utilization (ISRU...

  19. Intermediate processes in nuclear reactions

    International Nuclear Information System (INIS)

    The main results presented here cannot be interpreted in terms of the direct reaction model or the statistical models and one can more or less explicitely use some nuclear configurations for their interpretation. The first chapter deals with the so-called second order intermediate structures observed in the elastic and inelastic proton scattering on 66Zn and 70Ge targets in the energetic regions of some isobaric analog resonances. A formal theory for their interpretation is developed and the comparison with the experimental data is presented. New experimental results on the resonant structures observed in the elastic and inelastic scattering of 12C on 24Mg are presented in the second chapter. Detailed statistical analysis and their interpretation is presented too. Charge equilibration in deep inelastic collisions is the main subject of the third chapter. The experimental results obtained by the 98Mo + 154Sm collision at 12 MeV/n, a quantum treatment of a damped harmonic oscillator and the comparison with the experimental data are given. In the last chapter, some results on the existence of two other processes which could candidate to be involved in the main topic are presented. Those processes are: the fast fragmentation and preequilibrium charged particles emission. All these processes originate in the excitation of some simple configurations which can be seen on ''doorway'' states (''Hallway'' in the case of the second intermediate structures). The coupling of these states to other more complicated excitation modes of the nuclei and to outgoing channel=gives the possibility to study the nuclear dynamics. This justifies the interest for their detailed theoretical and experimental investigations. (author)

  20. Speeding chemical reactions by focusing

    Science.gov (United States)

    Lacasta, A. M.; Ramírez-Piscina, L.; Sancho, J. M.; Lindenberg, K.

    2013-04-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, and obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate ˜t-1/2 to very close to the perfect mixing rate, ˜t-1.

  1. Speeding chemical reactions by focusing

    CERN Document Server

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  2. Dynamic Reaction Figures: An Integrative Vehicle for Understanding Chemical Reactions

    Science.gov (United States)

    Schultz, Emeric

    2008-01-01

    A highly flexible learning tool, referred to as a dynamic reaction figure, is described. Application of these figures can (i) yield the correct chemical equation by simply following a set of menu driven directions; (ii) present the underlying "mechanism" in chemical reactions; and (iii) help to solve quantitative problems in a number of different…

  3. [Reaction mechanism studies of heavy ion induced nuclear reactions

    International Nuclear Information System (INIS)

    This report contains papers that discuss: Target Dependence of Complex Fragment Emission in 47-MeV/u La-Induced Reactions; Deconvolution of Time-of-Flight Data to Improve Mass Identification; and Study of the Reaction of La + Al at E/A = 50 MeV with Landau-Vlasov Dynamics

  4. Dynamics of fission and heavy ion reactions

    International Nuclear Information System (INIS)

    Recent advances in a unified macroscopic-microscopic description of large-amplitude collective nuclear motion such as occurs in fission and heavy ion reactions are discussed. With the goal of finding observable quantities that depend upon the magnitude and mechanism of nuclear dissipation, one-body dissipation and two-body viscosity within the framework of a generalized Fokker-Planck equation for the time dependence of the distribution function in phase space of collective coordinates and momenta are considered. Proceeding in two separate directions, the generalized Hamilton equations of motion for the first moments of the distribution function with a new shape parametrization and other technical innovations are first solved. This yields the mean translational fission-fragment kinetic energy and mass of a third fragment that sometimes forms between the two end fragments, as well as the energy required for fusion in symmetric heavy-ion reactions and the mass transfer and capture cross section in asymmetric heavy-ion reactions. In a second direction, we specialize to an inverted-oscillator fission barrier and use Kramers' stationary solution to calculate the mean time from the saddle point to scission for a heavy-ion-induced fission reaction for which experimental information is becoming available. 25 references

  5. Neutrino neutral current reactions in 12C

    Science.gov (United States)

    Parthasarathy, R.; Yesudian, Premkumar

    1985-05-01

    The differential and total cross sections for the nuclear reaction ν μ + 12C (g.s) → 12C ∗ (1 +; T = 1, 15.1 MeV) + νμ are investigated for values of 50 ≤ Eνμ ≤ 300 MeV. An effective Hamiltonian for the above nuclear reaction is constructed from the neutrino-quark neutral current weak interaction, by first constructing the neutrino-nucleon neutral current interaction and then using the impulse approximation along with the non-relativistic reduction procedure. The Weinberg-Salam model is the basis of the calculations. Detailed expressions for the differential cross sections are derived including the nucleon momentum-dependent terms. The numerical results are obtained using the general 1 p-shell wavefunctions of Cohen and Kurath. The sensitivity of the total cross sections to the nuclear models and to the Weinberg angle is studied. The corresponding anti-neutrino reaction is also investigated. The ratio R = (σ Tν μ - σ Toverlineνμ) /(σ Tν μ + σ Toverlineνμ) is found to be independent of the nuclear wavefunctions but very sensitive to the Weinberg angle. Thus this observable can be used to determine the free parameter θw in a nuclear reaction, thereby complementing the studies involving free nucleons. The recoil polarization of the final nucleus 12C ∗(1 +; T = 1, 15.1 MeV) is also studied and its importance is pointed out.

  6. Progress in microscopic direct reaction modeling of nucleon induced reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dupuis, M.; Bauge, E.; Hilaire, S.; Lechaftois, F.; Peru, S.; Pillet, N.; Robin, C. [CEA, DAM, DIF, Arpajon (France)

    2015-12-15

    A microscopic nuclear reaction model is applied to neutron elastic and direct inelastic scatterings, and pre-equilibrium reaction. The JLM folding model is used with nuclear structure information calculated within the quasi-particle random phase approximation implemented with the Gogny D1S interaction. The folding model for direct inelastic scattering is extended to include rearrangement corrections stemming from both isoscalar and isovector density variations occurring during a transition. The quality of the predicted (n,n), (n,n{sup '}), (n,xn) and (n,n{sup '}γ) cross sections, as well as the generality of the present microscopic approach, shows that it is a powerful tool that can help improving nuclear reactions data quality. Short- and long-term perspectives are drawn to extend the present approach to more systems, to include missing reactions mechanisms, and to consistently treat both structure and reaction problems. (orig.)

  7. Progress in microscopic direct reaction modeling of nucleon induced reactions

    International Nuclear Information System (INIS)

    A microscopic nuclear reaction model is applied to neutron elastic and direct inelastic scatterings, and pre-equilibrium reaction. The JLM folding model is used with nuclear structure information calculated within the quasi-particle random phase approximation implemented with the Gogny D1S interaction. The folding model for direct inelastic scattering is extended to include rearrangement corrections stemming from both isoscalar and isovector density variations occurring during a transition. The quality of the predicted (n,n), (n,n'), (n,xn) and (n,n'γ) cross sections, as well as the generality of the present microscopic approach, shows that it is a powerful tool that can help improving nuclear reactions data quality. Short- and long-term perspectives are drawn to extend the present approach to more systems, to include missing reactions mechanisms, and to consistently treat both structure and reaction problems. (orig.)

  8. Microscopic effective reaction theory for deuteron-induced reactions

    CERN Document Server

    Neoh, Yuen Sim; Minomo, Kosho; Ogata, Kazuyuki

    2016-01-01

    The microscopic effective reaction theory is applied to deuteron-induced reactions. A reaction model-space characterized by a $p+n+{\\rm A}$ three-body model is adopted, where A is the target nucleus, and the nucleon-target potential is described by a microscopic folding model based on an effective nucleon-nucleon interaction in nuclear medium and a one-body nuclear density of A. The three-body scattering wave function in the model space is obtained with the continuum-discretized coupled-channels method (CDCC), and the eikonal reaction theory (ERT), an extension of CDCC, is applied to the calculation of neutron removal cross sections. Elastic scattering cross sections of deuteron on $^{58}$Ni and $^{208}$Pb target nuclei at several energies are compared with experimental data. The total reaction cross sections and the neutron removal cross sections at 56 MeV on 14 target nuclei are calculated and compared with experimental values.

  9. Matrix isolation as a tool for studying interstellar chemical reactions

    Science.gov (United States)

    Ball, David W.; Ortman, Bryan J.; Hauge, Robert H.; Margrave, John L.

    1989-01-01

    Since the identification of the OH radical as an interstellar species, over 50 molecular species were identified as interstellar denizens. While identification of new species appears straightforward, an explanation for their mechanisms of formation is not. Most astronomers concede that large bodies like interstellar dust grains are necessary for adsorption of molecules and their energies of reactions, but many of the mechanistic steps are unknown and speculative. It is proposed that data from matrix isolation experiments involving the reactions of refractory materials (especially C, Si, and Fe atoms and clusters) with small molecules (mainly H2, H2O, CO, CO2) are particularly applicable to explaining mechanistic details of likely interstellar chemical reactions. In many cases, matrix isolation techniques are the sole method of studying such reactions; also in many cases, complexations and bond rearrangements yield molecules never before observed. The study of these reactions thus provides a logical basis for the mechanisms of interstellar reactions. A list of reactions is presented that would simulate interstellar chemical reactions. These reactions were studied using FTIR-matrix isolation techniques.

  10. Astronomy with Radioactivities: Chapter 9, Nuclear Reactions

    OpenAIRE

    Wiescher, M.; Rauscher, T.

    2010-01-01

    Nuclear reaction rates determine the abundances of isotopes in stellar burning processes. A multitude of reactions determine the reaction flow pattern which is described in terms of reaction network simulations. The reaction rates are determined by laboratory experiments supplemented by nuclear reaction and structure theory. We will discuss the experimental approach as well as the theoretical tools for obtaining the stellar reaction rates. A detailed analysis of a reaction is only possible fo...

  11. Chemistry of heavy ion reactions

    International Nuclear Information System (INIS)

    The use of heavy ions to induce nuclear reactions was reported as early as 1950. Since that time it has been one of the most active areas of nuclear research. Intense beams of ions as heavy as uranium with energies high enough to overcome the Coulomb barriers of even the heaviest elements are available. The wide variety of possible reactions gives rise to a multitude of products which have been studied by many ingenious chemical and physical techniques. Chemical techniques have been of special value for the separation and unequivocal identification of low yield species from the plethora of other nuclides present. Heavy ion reactions have been essential for the production of the trans-Md elements and a host of new isotopes. The systematics of compound nucleus reactions, transfer reactions, and deeply inelastic reactions have been elucidated using chemical techniques. A review of the variety of chemical procedures and techniques which have been developed for the study of heavy ion reactions and their products is given. Determination of the chemical properties of the trans-Md elements, which are very short-lived and can only be produced an ''atom-at-a-time'' via heavy ion reactions, is discussed. 53 refs., 19 figs

  12. Entropy Effects in Chelation Reactions.

    Science.gov (United States)

    Chung, Chung-Sun

    1984-01-01

    The entropy change for a reaction in aqueous solution can be evaluated as a combination of entropy factors. Valuable insight or understanding can be obtained from a detailed examination of these factors. Several entropy effects of inorganic chemical reactions are discussed as examples. (Author/JN)

  13. Symmetry violation in nuclear reactions

    International Nuclear Information System (INIS)

    Precision studies of nuclear reactions can be used to search for small violations of the discrete symmetries. Recent and proposed experimental work using nuclear reactions to study the breakdown of three symmetries - isospin (I), parity (P) and time-reversal (T) is reviewed. 44 references

  14. Free Radical Reactions in Food.

    Science.gov (United States)

    Taub, Irwin A.

    1984-01-01

    Discusses reactions of free radicals that determine the chemistry of many fresh, processed, and stored foods. Focuses on reactions involving ascorbic acid, myoglobin, and palmitate radicals as representative radicals derived from a vitamin, metallo-protein, and saturated lipid. Basic concepts related to free radical structure, formation, and…

  15. Zeolite Catalyzed Aldol Condensation Reactions

    Directory of Open Access Journals (Sweden)

    Adedayo I. Inegbenebor

    2015-03-01

    Full Text Available The review is based on the description of zeolite structure, uses, synthesis, and catalytic aldol reaction in aldol condensation. An internal aldolcondensation reaction has been achieved over ZSM-5 zeolite with high silica-alumina ratio at 350oC. It therefore follows that zeolite canfunction as a catalyst in aldol type condensation reactions and that weak acid sites as well as a small number of active sites favor the aldolcondensation reaction of carbonyl compounds. However, the mixed condensation product was found to be favored at temperatures above 300oCand the self-condensation of ethanal to crotonaldehyde was favored at temperatures below 300oC. It has also been suggested that both Brønstedand Lewis acids are involved in aldol reactions with Lewis acid sites the most probable catalytic sites. The zeolite group of minerals has founduse in many chemical and allied industries.

  16. Enzymatic reactions in confined environments

    Science.gov (United States)

    Küchler, Andreas; Yoshimoto, Makoto; Luginbühl, Sandra; Mavelli, Fabio; Walde, Peter

    2016-05-01

    Within each biological cell, surface- and volume-confined enzymes control a highly complex network of chemical reactions. These reactions are efficient, timely, and spatially defined. Efforts to transfer such appealing features to in vitro systems have led to several successful examples of chemical reactions catalysed by isolated and immobilized enzymes. In most cases, these enzymes are either bound or adsorbed to an insoluble support, physically trapped in a macromolecular network, or encapsulated within compartments. Advanced applications of enzymatic cascade reactions with immobilized enzymes include enzymatic fuel cells and enzymatic nanoreactors, both for in vitro and possible in vivo applications. In this Review, we discuss some of the general principles of enzymatic reactions confined on surfaces, at interfaces, and inside small volumes. We also highlight the similarities and differences between the in vivo and in vitro cases and attempt to critically evaluate some of the necessary future steps to improve our fundamental understanding of these systems.

  17. Sodium concrete reaction: structural considerations

    International Nuclear Information System (INIS)

    An overview of the sodium concrete reaction phenomenon, with emphasis on structural considerations, is presented. Available test results for limestone, basalt, and magnetite concrete with various test article configurations are reviewed. Generally, tests indicate reaction is self limiting before all sodium is used. Uncertainties, however, concerning the mechanism for penetration of sodium into concrete have resulted in different theories about a reaction model. Structural behavior may be significant in the progression of the reaction due to thermal-structural-chemical interactions involving tensile cracking, compressive crushing, or general deterioration of concrete and the exposure of fresh concrete surfaces to react with sodium. Structural behavior of test articles and potential factors that could enhance the progression of the reaction are discussed

  18. Asymmetric Michael Reaction of Malononitrile Catalyzed by Chiral Ru(Ⅱ) Complex and Achiral Base

    Institute of Scientific and Technical Information of China (English)

    MA Ya-Ping; XING Zhi-Kui; ZHU Jin; CUI Xin; CUN Lin-Feng; DENG Jin-Gen

    2003-01-01

    @@ Michael addition reactions represent one of the most important carbon-carbon bond forming reactions in modern synthetic organic chemistry. [1 ~3] We achieved catalytic enantioselective Michael addition reactions of malononitrile with chiral vicinal diamine-Ru(Ⅱ) complex in the presence of achiral base. High yields and moderate ee were observed.

  19. Performance of Lightweight Concrete based on Granulated Foamglass

    Science.gov (United States)

    Popov, M.; Zakrevskaya, L.; Vaganov, V.; Hempel, S.; Mechtcherine, V.

    2015-11-01

    The paper presents an investigation of lightweight concretes properties, based on granulated foamglass (GFG-LWC) aggregates. The application of granulated foamglass (GFG) in concrete might significantly reduce the volume of waste glass and enhance the recycling industry in order to improve environmental performance. The conducted experiments showed high strength and thermal properties for GFG-LWC. However, the use of GFG in concrete is associated with the risk of harmful alkali-silica reactions (ASR). Thus, one of the main aims was to study ASR manifestation in GFG-LWC. It was found that the lightweight concrete based on porous aggregates, and ordinary concrete, have different a mechanism of ASR. In GFG-LWC, microstructural changes, partial destruction of granules, and accumulation of silica hydro-gel in pores were observed. According to the existing methods of analysis of ASR manifestation in concrete, sample expansion was measured, however, this method was found to be not appropriate to indicate ASR in concrete with porous aggregates. Microstructural analysis and testing of the concrete strength are needed to evaluate the damage degree due to ASR. Low-alkali cement and various pozzolanic additives as preventive measures against ASR were chosen. The final composition of the GFG-LWC provides very good characteristics with respect to compressive strength, thermal conductivity and durability. On the whole, the potential for GFG-LWC has been identified.

  20. Application of Image Analysis to Identify Quartz Grains in Heavy Aggregates Susceptible to ASR in Radiation Shielding Concrete

    Directory of Open Access Journals (Sweden)

    Daria Jóźwiak-Niedźwiedzka

    2016-03-01

    Full Text Available Alkali-silica reaction (ASR is considered as a potential aging-related degradation phenomenon that might impair the durability of concrete in nuclear containments. The objective of this paper is the application of digital analysis of microscopic images to identify the content and size of quartz grains in heavy mineral aggregates. The range of investigation covered magnetite and hematite aggregates, known as good absorbers of gamma radiation. Image acquisition was performed using thin sections observed in transmitted cross-polarized light with λ plate. Image processing, consisting of identification of ferrum oxide and epoxy resin, and the subsequent application of a set of filtering operations resulted in an adequate image reduction allowing the grain size analysis. Quartz grains were classified according to their mean diameter so as to identify the reactive range. Accelerated mortar bar tests were performed to evaluate the ASR potential of the aggregates. The SiO2 content in the heavyweight aggregates determined using the image analysis of thin sections was similar to XRF test result. The content of reactive quartz hematite was 2.7%, suggesting that it would be prone to ASR. The expansion test, according to ASTM C1260, confirmed the prediction obtained using the digital image analysis.

  1. Effects of lithium nitrate admixture on early-age cement hydration

    International Nuclear Information System (INIS)

    Although the benefits of lithium admixtures for mitigation of alkali-silica reaction (ASR) have been well documented, the potential ancillary effects of lithium compounds on cement and concrete remain largely uncharacterized. To examine the effects of the most common lithium admixture - lithium nitrate - on early-age behavior, the admixture was introduced at dosages of 0% to 400% of the recommended dosage to six cements of varying composition and to a cement-fly ash blend. Behavior was examined by isothermal calorimetry and measurements of chemical shrinkage, autogenous shrinkage, and setting time. Results indicate that lithium nitrate accelerates the early hydration of most cements but may retard hydration after 24 h. In the lowest alkali cement tested, set times were shortened in the presence of lithium nitrate by 15-22%. Higher dosages appeared to increase autogenous shrinkage after 40 days. The replacement of cement by Class F fly ash at 20% by weight appeared to diminish the early acceleration effects, but later hydration retardation and autogenous shrinkage were still observed

  2. Molecular polarizabilities in aqueous proton transfer reactions

    International Nuclear Information System (INIS)

    Dipole polarizabilities of individual ions and molecules are computed from first principles in three condensed-phase systems: pure water, pure hydrofluoric acid, and an equimolar mixture of water and hydrofluoric acid in which HF is mostly ionized. We find that the polarizability of fluorine and oxygen centers varies linearly with the value of the bond order, which measures the local degree of advancement of the ionization reaction F-H+H2O[Fδ-·H·δ+OH2]F-+H3O+. This observation explains the validity of the Lorentz-Lorenz formula for mixtures of acids and water and could have important practical consequences concerning the construction of empirical polarizable reactive force fields. Our results are consistent with the Mulliken charge-transfer picture of proton transfer reactions. The present results also suggest that the average isotropic polarizability of a chemical entity changes substantially only when that entity is involved in charge-transfer processes.

  3. Reaction kinetics of bond rotations in graphene

    KAUST Repository

    Skowron, Stephen T.

    2016-04-12

    The formation and healing processes of the fundamental topological defect in graphitic materials, the Stone-Wales (SW) defect, are brought into a chemical context by considering the rotation of a carbon-carbon bond as chemical reaction. We investigate the rates and mechanisms of these SW transformations in graphene at the atomic scale using transmission electron microscopy. We develop a statistical atomic kinetics formalism, using direct observations obtained under different conditions to determine key kinetic parameters of the reactions. Based on the obtained statistics we quantify thermally and irradiation induced routes, identifying a thermal process of healing with an activation energy consistent with predicted adatom catalysed mechanisms. We discover exceptionally high rates for irradiation induced SW healing, incompatible with the previously assumed mechanism of direct knock-on damage and indicating the presence of an efficient nonadiabatic coupling healing mechanism involving beam induced electronic excitations of the SW defect.

  4. A review of tritium conversion reactions

    International Nuclear Information System (INIS)

    The chemical processes by which elemental tritium can be converted to tritiated water have been examined by reviewing the available literature on these processes. It would appear that gas phase conversion reactions at room temperature are slow and that they do not contribute significantly to any observed conversion following releases of elemental tritium. The effects of surfaces are not clearly understood. Metals, however, can increase the rate over the gas phase processes, but the magnitude of this increase is not well documented. Further work is necessary to examine the effects of various materials, elevated temperatures, and other parameters on conversion reactions in order to more closely reflect conditions in reactor buildings and other tritium containing facilities

  5. Light particle revelation on incomplete fusion reactions

    International Nuclear Information System (INIS)

    Incomplete fusion reactions have been studied through light particles emission in the reaction 116Sn + 16O at 125 MeV (ALICE facility in Orsay). We measured energy angular distributions and correlations between any two of these particles (α particles, protons, neutrons), while γ multiplicity measurements provide us fuller informations. From collected data, the following pictures can be drawn: - the only fast particles observed are α particles, while protons and neutrons seem to come only from statistical evaporation; - outgoing channels where two α particles are emitted cannot be solely explained by the sequential emission of 8Be → 2α: about half of the cross section proceeds from statistical evaporation of one α particle. Accordingly, 2αxn channels do not necessarily agree with high value of angular momentum in the entrance channel. From the study of experimental results in the yrast plane, we can assign a large width to the angular momentum distribution

  6. Transfer reaction code with nonlocal interactions

    CERN Document Server

    Titus, L J; Nunes, F M

    2016-01-01

    We present a suite of codes (NLAT for nonlocal adiabatic transfer) to calculate the transfer cross section for single-nucleon transfer reactions, $(d,N)$ or $(N,d)$, including nonlocal nucleon-target interactions, within the adiabatic distorted wave approximation. For this purpose, we implement an iterative method for solving the second order nonlocal differential equation, for both scattering and bound states. The final observables that can be obtained with NLAT are differential angular distributions for the cross sections of $A(d,N)B$ or $B(N,d)A$. Details on the implementation of the T-matrix to obtain the final cross sections within the adiabatic distorted wave approximation method are also provided. This code is suitable to be applied for deuteron induced reactions in the range of $E_d=10-70$ MeV, and provides cross sections with $4\\%$ accuracy.

  7. The 'compensation effect' in the graphite/CO2 reaction

    International Nuclear Information System (INIS)

    The compensation effect is the often observed linear relationship between the activation energy and pre-exponential factor in the Arrhenius equations of a series of related reactions. Previously reported studies of the graphite/CO2 reaction at different total pressures and CO2/CO ratios are used as an example of the compensation effect. The effect is shown in general to be an artefact produced by a strong correlation between the parameter estimates in the conventional Arrhenius plot. A transformation of the Arrhenius plot to minimise the overall correlation between estimates and thus enable detection of a true compensation effect is presented. The results of this transformation on the kinetic data for the graphite/CO2 reaction are consistent with previous analyses of the reaction system. They show that there is only a limited compensation effect within this study and demonstrate the influence of the approach to equilibrium of the graphite/CO2 reaction. (author)

  8. Isotopic exchange in ion-molecule reactions: interstellar implications

    International Nuclear Information System (INIS)

    The results of a study of the rates of isotopic exchange in several positive ion/molecule reactions are outlined. The data were obtained over the temperature range 90 - 550 K using a SIFT apparatus. Reversible reactions of the kind: 13C+ + 12CO reversible 12C+ + 13CO were studied and the rate coefficients were determined. Other similar reactions studied were those between HCO+ and CO in which the carbon and oxygen were variously isotopically labelled. Differences between the rate coefficients were apparent at the lower temperatures which, it is suggested, contribute to the observed enhanced concentrations of the rarer isotopes in interstellar CO and HCO+. Isotopic exchange in the reactions of CH+, CH2+ and CH3+ with HD and D2 and in the reactions of CD+, CD2+ and CD3+ with HD and H2 has also been studied and these data are briefly discussed. (Auth.)

  9. Dynamics of synchrotron VUV-induced intracluster reactions

    Energy Technology Data Exchange (ETDEWEB)

    Grover, J.R. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    Photoionization mass spectrometry (PIMS) using the tunable vacuum ultraviolet radiation available at the National Synchrotron Light Source is being exploited to study photoionization-induced reactions in small van der Waals mixed complexes. The information gained includes the observation and classification of reaction paths, the measurement of onsets, and the determination of relative yields of competing reactions. Additional information is obtained by comparison of the properties of different reacting systems. Special attention is given to finding unexpected features, and most of the reactions investigated to date display such features. However, understanding these reactions demands dynamical information, in addition to what is provided by PIMS. Therefore the program has been expanded to include the measurement of kinetic energy release distributions.

  10. Quantum effects in unimolecular reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gezelter, J.D.

    1995-12-01

    This work is primarily concerned with the development of models for the quantum dynamics of unimolecular isomerization and photodissociation reactions. We apply the rigorous quantum methodology of a Discrete Variable Representation (DVR) with Absorbing Boundary Conditions (ABC) to these models in an attempt to explain some very surprising results from a series of experiments on vibrationally excited ketene. Within the framework of these models, we are able to identify the experimental signatures of tunneling and dynamical resonances in the energy dependence of the rate of ketene isomerization. Additionally, we investigate the step-like features in the energy dependence of the rate of dissociation of triplet ketene to form {sup 3}B{sub 1} CH{sub 2} + {sup 1}{sigma}{sup +} CO that have been observed experimentally. These calculations provide a link between ab initio calculations of the potential energy surfaces and the experimentally observed dynamics on these surfaces. Additionally, we develop an approximate model for the partitioning of energy in the products of photodissociation reactions of large molecules with appreciable barriers to recombination. In simple bond cleavage reactions like CH{sub 3}COCl {yields} CH{sub 3}CO + Cl, the model does considerably better than other impulsive and statistical models in predicting the energy distribution in the products. We also investigate ways of correcting classical mechanics to include the important quantum mechanical aspects of zero-point energy. The method we investigate is found to introduce a number of undesirable dynamical artifacts including a reduction in the above-threshold rates for simple reactions, and a strong mixing of the chaotic and regular energy domains for some model problems. We conclude by discussing some of the directions for future research in the field of theoretical chemical dynamics.

  11. Reaction dynamics and photochemistry of divalent systems

    Energy Technology Data Exchange (ETDEWEB)

    Davis, H.F.

    1992-05-01

    Results are presented of molecular beam studies of bimolecular and unimolecular reactions of Ba. Chapter 1 discusses the reaction Ba + NO{sub 2}. Formation of the dominant BaO({sup 1}{Sigma}) + NO products resulted primarily from decay of long-lived Ba{sup +}NO{sub 2}{sup {minus}} collision complexes. Secondary mechanisms led to formation of forward scattered, internally excited BaO, and BaNO + O. D{sub o}(Ba-NO) = 65{plus_minus}20 kcal/mol. Reactions of ground state and electronically excited Ba with water and alcohols are examined in Chapter 2. Reaction of Ba({sup 1}S) + H{sup 2}O led to BaO + H{sub 2}, whereas excited state Ba({sup 1}D) + H{sub 2}O reacted to form BaOH + H. Collisions between Ba and CH{sub 3}OH led to BaOCH{sub 3} + H. Radical channels involve H-atom migration and are promoted by excitation of the incident Ba atom. In Chapter 3, reactions of Ba({sup 1}S) with ClO{sub 2}2 and O{sub 3} are discussed. Again, direct and complex mechanisms were observed. Formation of BaCl + O{sub 2} from decomposition of Ba{sup +}ClO{sub 2}{sup {minus}} accounted for 10% of total reaction crass section. Although Ba + O{sub 3} {yields} BaO + 0{sub 2} occurs primarily by direct reaction mechanisms, the secondary channel Ba + 0{sub 3} {yields} BaO{sub 2} + 0 involved decay of long lived Ba{sup +}O{sub 3}{sup {minus}} intermediates. D{sub o}(Ba{minus}O{sub 2}) = 120 {plus_minus}20 kcal/mol. Photodissociation dynamics of NO{sub 3} is explored in chapter 4. Visible excitation leads to formation of NO + 0{sub 2} and NO{sub 2} + O. Wavelength dependence of branching ratios is investigated. D{sub o}(O-NO{sub 2}) = 48.55 kcal/mole ;and calculate {Delta}H{sub f}(NO{sub 3}) = 17.75 kcal/mole (298K). Chapter 5 discusses the photodissociation of OClO in a molecular beam. Although ClO({sup 2}II) + O({sup 3}P) is dominant, Cl({sup 2}P) + O{sub 2} also forms, with a max yield of 3.9{plus_minus}0.8% near 404nm.

  12. Thin film reactions on alloy semiconductor substrates

    Energy Technology Data Exchange (ETDEWEB)

    Olson, D.A.

    1990-11-01

    The interactions between Pt and In{sub .53}Ga{sub .47}As have been studied. In{sub .53}Ga{sub .47}As substrates with 70nm Pt films were encapsulated in SiO{sub 2}, and annealed up to 600{degree}C in flowing forming gas. The composition and morphology of the reaction product phases were studied using x-ray diffraction, Auger depth profiling, and transmission electron microscopy. The reaction kinetics were examined with Rutherford Backscattering. Results show that Pt/In{sub .53}Ga{sub .47}As reacts to form many of the reaction products encountered in the Pt/GaAs and Pt/InP reactions: PtGa, Pt{sub 3}Ga, and PtAs{sub 2}. In addition, a ternary phase, Pt(In:Ga){sub 2}, develops, which is a solid solution between PtIn{sub 2} and PtGa{sub 2}. The amount of Ga in the ternary phase increases with annealing temperature, which causes a decrease in the lattice parameter of the phase. The reaction products show a tendency to form layered structures, especially for higher temperatures and longer annealing times. Unlike the binary case, the PtAs{sub 2}, phase is randomly oriented on the substrate, and is intermingle with a significant amount of Pt(In:Ga){sub 2}. Following Pt/In{sub .53}Ga{sub .47}As reactions, two orientation relationships between the Pt(In:Ga){sub 2} product phase and the substrate were observed, despite the large mismatch with the substrate ({approximately}8%). For many metal/compound semiconductor interactions, the reaction rate is diffusion limited, i.e. exhibits a parabolic dependence on time. An additional result of this study was the development of an In-rich layer beneath the reacted layer. The Auger depth profile showed a substantial increase in the sample at this layer. This is a significant result for the production of ohmic contacts, as the Schottky barrier height in this system lower for higher In concentrations. 216 refs.

  13. Metal Chelation in Asymmetric Diels-Alder Reaction (II)

    International Nuclear Information System (INIS)

    In the reaction, the inverse asymmetric induction has been observed by the use of either monovalent Lewis acids or divalent Lewis acids. The reaction of the acrylate of (S)-ethyl lactate with cyclopentadiene proceeded with 86% endo-S selectivity in the presence of TiCl4, divalent Lewis acid, whereas did with 32% endo-R selectivity in the presence of BF3·Et2O, monovalent Lewis acid. When a chiral dienophile which was prepared from benzyl ester of (S)-proline or methyl ester of (S)-indoline-2-carboxylic acid was employed in the reaction, a similar diastereofacial selectivity was also observed. Recently, we reported the similar selectivity in the reaction of methyl (2S,5S)-(5-t-butyldimethylsilyloxypiperidin- 2-yl)ethanoatewith cyclopentadiene.

  14. Investigating ionic effects applied to water based organocatalysed aldol reactions.

    Science.gov (United States)

    Delaney, Joshua P; Henderson, Luke C

    2011-01-01

    Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C(2)-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA) into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination. PMID:22272120

  15. Enhancement of Sonochemical Reaction by Dual-Pulse Ultrasound

    Science.gov (United States)

    Xu, Zheng; Yasuda, Keiji

    2011-07-01

    In order to apply sonochemistry in wastewater treatment, enhancement of sonochemical reaction is necessary. Oxidation of potassium iodide and the degradation of acid orange 7 in aqueous solution using ultrasound irradiation were performed at 490 kHz. Power-modulated pulsed waves were employed and the enhancement of reaction amount was observed compared with using continuous wave. The enhancement ratio for irradiation to rigid wall was larger than that for irradiation to free surface. Moreover, the best modulated pulsed on time was experimentally determined and the effect of the superposition of pulsed waves (dual-pulse) was studied. Enhancement was also observed and calculated separately when using dual-pulse ultrasound. The enhancement upon the use of the dual-transducer was ascribed to the enlargement of sonochemical reaction field. The enhancement upon the incorporating pulsed waves was ascribed to both the reduction of reaction threshold effect and the residual acoustical pressure at the pulsed off time.

  16. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

    Full Text Available Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination.

  17. Revealing Stepwise Mechanisms in Dipolar Cycloaddition Reactions: Computational Study of the Reaction between Nitrones and Isocyanates.

    Science.gov (United States)

    Darù, Andrea; Roca-López, David; Tejero, Tomás; Merino, Pedro

    2016-01-15

    The mechanism of cycloaddition reactions of nitrones with isocyanates has been studied using density functional theory (DFT) methods at the M06-2X/cc-pVTZ level of theory. The exploration of the potential energy surfaces associated with two reactive channels leading to 1,2,4-oxadiazolidin-5-ones and 1,4,2-dioxazolidines revealed that the cycloaddition reaction takes place through a concerted mechanism in gas phase and in apolar solvents but a stepwise mechanism in polar solvents. In stepwise mechanisms, the first step of the reaction is a rare case in which the nitrone oxygen acts as a nucleophile by attacking the central carbon atom of the isocyanate (interacting with the π-system of the C═O bond) to give an intermediate. The corresponding transition structure is stabilized by an attractive electrostatic interaction favored in a polar medium. The second step of the reaction is the rate-limiting one in which the formation of 1,2,4-oxadiazolidin-5-ones or 1,4,2-dioxazolidines is decided. Calculations indicate that formation of 1,2,4-oxadiazolidin-5-ones is favored both kinetically and thermodynamically independently of the solvent, in agreement with experimental observations. Noncovalent interactions (NCI) and topological analysis of the gradient field of electron localization function (ELF) bonding confirmed the observed interactions. PMID:26682934

  18. Integrated Microreactors for Reaction Automation: New Approaches to Reaction Development

    Science.gov (United States)

    McMullen, Jonathan P.; Jensen, Klavs F.

    2010-07-01

    Applications of microsystems (microreactors) in continuous-flow chemistry have expanded rapidly over the past two decades, with numerous reports of higher conversions and yields compared to conventional batch benchtop equipment. Synthesis applications are enhanced by chemical information gained from integrating microreactor components with sensors, actuators, and automated fluid handling. Moreover, miniaturized systems allow experiments on well-defined samples at conditions not easily accessed by conventional means, such as reactions at high pressure and temperatures. The wealth of synthesis information that could potentially be acquired through use of microreactors integrated with physical sensors and analytical chemistry techniques for online reaction monitoring has not yet been well explored. The increased efficiency resulting from use of continuous-flow microreactor platforms to automate reaction screening and optimization encourages a shift from current batchwise chemical reaction development to this new approach. We review advances in this new area and provide application examples of online monitoring and automation.

  19. Anisotropic Inflation and Cosmological Observations

    CERN Document Server

    Emami, Razieh

    2015-01-01

    Recent observations opened up a new window on the inflationary model building. As it was firstly reported by the WMAP data, there may be some indications of statistical anisotropy on the CMB map, although the statistical significance of these findings are under debate. Motivated by these observations, people begun considering new inflationary models which may lead to statistical anisotropy. The simplest possible way to construct anisotropic inflation is to introduce vector fields. During the course of this thesis, we study models of anisotropic inflation and their observational implications such as power spectrum, bispectrum etc. Firstly we build a new model, which contains the gauge field which breaks the conformal invariance while preserving the gauge invariance. We show that in these kind of models, there can be an attractor phase in the evolution of the system when the back-reaction of the gauge field becomes important in the evolution of the inflaton field. We then study the cosmological perturbation the...

  20. Nuclear Reactions at Intermediate Energies

    CERN Document Server

    Shyam, Radhey

    2015-01-01

    In the domain of Nuclear reactions at intermediate energies, the QCD coupling constant $\\alpha_s$ is large enough ($\\sim$ 0.3 - 0.5) to render the perturbative calculational techniques inapplicable. In this regime the quarks are confined into colorless hadrons and it is expected that effective field theories of hadron interactions via exchange of hadrons, provide useful tools to describe such reactions. In this contribution we discuss applications of one such theory, the effective Lagrangian model, in describing the hadronic reactions at intermediate energies whose measurements are the focus of a vast international experimental program.

  1. Palladium-catalyzed coupling reactions

    CERN Document Server

    Molnár, Árpád

    2013-01-01

    This handbook and ready reference brings together all significant issues of practical importance for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of modern-day coupling reactions and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With i

  2. Hypersensitivity reaction associated with phenytoin.

    Science.gov (United States)

    Indu, T H; Basutkar, Roopa Satyanarayan

    2015-09-01

    Hypersensitivity reactions with antiepileptic drugs (AEDs) are generally associated with aromatic AEDs. We present a case of hypersensitivity reactions followed by administration of phenytoin with diazepam and ranitidine in a patient with generalized tonic-clonic seizures. Antigen-antibody reactions or decreased levels of epoxide hydrolase are well known with phenytoin. Increased level of serum phenytoin causing toxicities due to competitive inhibition with diazepam on co-administration was also reported in the literature. Prevention of the adverse effects with AEDs is a multi-stage process, which requires implementation of preventive measures through careful monitoring and prompts interventions. PMID:26692739

  3. Statistical properties of multistep enzyme-mediated reactions

    OpenAIRE

    de Ronde, Wiet H.; Daniels, Bryan C.; Mugler, Andrew; Sinitsyn, Nikolai A.; Nemenman, Ilya

    2008-01-01

    Enzyme-mediated reactions may proceed through multiple intermediate conformational states before creating a final product molecule, and one often wishes to identify such intermediate structures from observations of the product creation. In this paper, we address this problem by solving the chemical master equations for various enzymatic reactions. We devise a perturbation theory analogous to that used in quantum mechanics that allows us to determine the first () and the second (variance) cumu...

  4. Immediate reaction to lidocaine with periorbital edema during upper blepharoplasty

    OpenAIRE

    Benjamin Presman; Vincenzo Vindigni; Ilaria Tocco-Tussardi

    2016-01-01

    Introduction: Blepharoplasty is the fourth most commonly performed cosmetic surgery in the US, with 207,000 operations in 2014. Lidocaine is the preferred anesthetic agent for blepharoplasty. Presentation of case: We describe the unusual case of acute periorbital edema following local anesthesia with lidocaine for upper blepharoplasty. At present, only two other reports of periorbital reactions to lidocaine are present in the literature. The reactions observed are significant palpebral swe...

  5. Pre-compound neutron evaporation in heavy ion fusion reactions

    International Nuclear Information System (INIS)

    In the present investigation, exclusive neutron spectra have been measured in coincidence with the observed γ-rays characteristic to the residual nuclei 53Fe, 55Fe and 56Co. In this new experimental study, we have followed the strategy of forming the compound nucleus 58Ni at the same excitation energy through two different entrance channels viz the mass symmetric reaction 31P +27Al and the mass asymmetric reaction 12C + 46Ti

  6. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    OpenAIRE

    Joshua P. Delaney; Henderson, Luke C.

    2011-01-01

    Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibiti...

  7. Radiochemical studies of fast neutron induced reactions at KFA JUELICH

    International Nuclear Information System (INIS)

    The results of radiochemical study of neutron induced threshold reactions are reported. Integral cross-sections were measured by the activation technique. Tritium and 3He formation cross-sections were determined at 14.6 MeV neutron energy and on neutron spectrum from d-Be break-up reaction. Some preliminary systematic trends observed in the cross-section data described. Some general results of nuclear data measurement for reactor techology are discussed

  8. Kinetics and Mechanisms of Calcite Reactions with Saline Waters

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Piers; *Morse, John W. (*/deceased)

    2010-11-15

    1. Objective The general objective of this research was to determine the kinetics and mechanisms of calcite reactions with saline waters over a wide range of saline water composition, carbon dioxide partial pressure (pCO2), and modest ranges of T and P. This would be done by studying both reaction rates and solubility from changes in solution chemistry. Also, nanoscale observations of calcite surface morphology and composition would be made to provide an understanding of rate controlling mechanisms.

  9. Pre-equilibrium decay processes in energetic heavy ion reactions

    International Nuclear Information System (INIS)

    The Boltzmann master equation (BME) is defined for application to precompound decay in heavy ion reactions in the 10 100 MeV/nucleon regime. Predicted neutron spectra are compared with measured results for central collisions of 20Ne and 12C with 165Ho target nuclei. Comparisons are made with subthreshold π0 yields in heavy ion reactions between 35 and 84 MeV/nucleon, and with the π0 spectra. The BME is found to be an excellent tool for investigating these experimentally observed aspects of non-equilibrium heavy ion reactions. 18 refs., 8 figs

  10. Signaling reactions on membrane surfaces: breaking the law of averages

    Science.gov (United States)

    Groves, Jay T.

    Most intracellular signal transduction reactions take place on the membrane surface. The membrane provides much more than just a surface environment on which signaling molecules are concentrated. There is a growing realization that multiple physical and chemical mechanisms allow the membrane to actively participate in the signaling reactions. Using a combination of single molecule imaging and spectroscopic techniques, my research seeks to directly resolve the actual mechanics of signaling reactions on membrane surfaces both in reconstituted systems and in living cells. These observations are revealing new insights into cellular signaling processes as well as some unexpected functional behaviors of proteins on the membrane surface.

  11. Theoretical study on the reaction of VS+(3∑-, 1Γ) with CO

    Institute of Scientific and Technical Information of China (English)

    Shi Wen Yu; Li Qing Yin; Li Feng Yao; Ming Li; Xiao Guang Xie

    2008-01-01

    Two possible reaction mechanisms of VS+(3Ε-, 1Γ) with CO in the gas phase have been studied by using B3LYP/TZVP and CCSD(T)/6-311+G (3df, 3pd) methods: the O/S exchange reaction (VS+ + CO → VO+ + CS) and the S-transfer reaction (VS+ + CO → V+ + COS). The two reactions proceed via two-step and one-step mechanism, respectively. The barriers of the triplet and singlet PESs are 30.6 and 50.9 kcal/mol, respectively, for O/S exchange reaction and 7.3 and 50.2 kcal/mol, respectively, for the S-transfer reaction. The results indicate that the triplet ground state reaction is more favorable, and the S-transfer reaction is more favorable than the O/S exchange reaction, which is in good agreement with the experimental observation.

  12. A topological characterization of medium-dependent essential metabolic reactions.

    Science.gov (United States)

    Sonnenschein, Nikolaus; Marr, Carsten; Hütt, Marc-Thorsten

    2012-01-01

    Metabolism has frequently been analyzed from a network perspective. A major question is how network properties correlate with biological features like growth rates, flux patterns and enzyme essentiality. Using methods from graph theory as well as established topological categories of metabolic systems, we analyze the essentiality of metabolic reactions depending on the growth medium and identify the topological footprint of these reactions. We find that the typical topological context of a medium-dependent essential reaction is systematically different from that of a globally essential reaction. In particular, we observe systematic differences in the distribution of medium-dependent essential reactions across three-node subgraphs (the network motif signature of medium-dependent essential reactions) compared to globally essential or globally redundant reactions. In this way, we provide evidence that the analysis of metabolic systems on the few-node subgraph scale is meaningful for explaining dynamic patterns. This topological characterization of medium-dependent essentiality provides a better understanding of the interplay between reaction deletions and environmental conditions. PMID:24957651

  13. A Topological Characterization of Medium-Dependent Essential Metabolic Reactions

    Directory of Open Access Journals (Sweden)

    Nikolaus Sonnenschein

    2012-09-01

    Full Text Available Metabolism has frequently been analyzed from a network perspective. A major question is how network properties correlate with biological features like growth rates, flux patterns and enzyme essentiality. Using methods from graph theory as well as established topological categories of metabolic systems, we analyze the essentiality of metabolic reactions depending on the growth medium and identify the topological footprint of these reactions. We find that the typical topological context of a medium-dependent essential reaction is systematically different from that of a globally essential reaction. In particular, we observe systematic differences in the distribution of medium-dependent essential reactions across three-node subgraphs (the network motif signature of medium-dependent essential reactions compared to globally essential or globally redundant reactions. In this way, we provide evidence that the analysis of metabolic systems on the few-node subgraph scale is meaningful for explaining dynamic patterns. This topological characterization of medium-dependent essentiality provides a better understanding of the interplay between reaction deletions and environmental conditions.

  14. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    A. Hansel

    2009-02-01

    Full Text Available Oxidation of isoprene through reaction with NO3 is a significant sink for isoprene that persists after dark. The products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene+NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 62±6% and the combined yield of MACR+MVK is found to be ~10%. Additional hydrocarbon products, thought to be primarily C4 and C5 carbonyl compounds, were observed by the PTR-MS at various m/z ratios and their yields quantified. These other oxidation products are used as additional constraints on the reaction mechanism.

  15. A product study of the isoprene+NO3 reaction

    Directory of Open Access Journals (Sweden)

    R. C. Cohen

    2009-07-01

    Full Text Available Oxidation of isoprene through reaction with NO3 radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NOx sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO3 reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NOx. Product formation in the isoprene + NO3 reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF. The organic nitrate yield is found to be 65±12% of which the majority was nitrooxy carbonyls and the combined yield of methacrolein and methyl vinyl ketone (MACR+MVK is found to be ∼10%. PTR-MS measurements of nitrooxy carbonyls and TD-LIF measurements of total organic nitrates agreed well. The PTR-MS also observed a series of minor oxidation products which were tentatively identified and their yields quantified These other oxidation products are used as additional constraints on the reaction mechanism.

  16. Reactions with light exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenthäler, R.; Faria, P.N. de; Pires, K.C.C.; Lepine-Szily, A.; Guimaraes, V.; Mendes Junior, D.R.; Assuncao, M.; Barioni, A.; Morcelle, V.; Morais, M.C.; Camargo Junior, O.; Alcantara Nuñez, J. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Moro, A.M. [Departamento de FAMN, Universidad de Sevilla, Sevilla (Spain); Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina); Rodriguez-Gallardo, M. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)

    2014-07-01

    Experimental cross sections for the {sup 6}He+{sup 120}Sn are analysed. Elastic scattering angular distributions and alpha particle production cross sections have been measured and are compared with the total reaction cross sections. (author)

  17. Transfer reactions in nuclear astrophysics

    Science.gov (United States)

    Bardayan, D. W.

    2016-08-01

    To a high degree many aspects of the large-scale behavior of objects in the Universe are governed by the underlying nuclear physics. In fact the shell structure of nuclear physics is directly imprinted into the chemical abundances of the elements. The tranquility of the night sky is a direct result of the relatively slow rate of nuclear reactions that control and determines a star’s fate. Understanding the nuclear structure and reaction rates between nuclei is vital to understanding our Universe. Nuclear-transfer reactions make accessible a wealth of knowledge from which we can extract much of the required nuclear physics information. A review of transfer reactions for nuclear astrophysics is presented with an emphasis on the experimental challenges and opportunities for future development.

  18. Reaction-bonded silicon nitride

    International Nuclear Information System (INIS)

    Reaction-bonded silicon nitride (RBSN) has been characterized. The oxidation behaviour in air up to 15000C and 3000 h and the effects of static and cyclic oxidation on room-temperature strength have been studied. (orig./IHOE)

  19. Statistical emission in nuclear reactions

    International Nuclear Information System (INIS)

    Statistical model in nuclear reactions has been extensively developed in the past decades, mainly by V. Weisskopf. However, a clear understanding of the experimental situation regarding low- and medium- energy nuclear reaction is not yet settled. The interpretation is complicated by the fact that often the reactions proceed via other mechanisms, for instance direct effects. The purpose 'of the present paper is to show how a great number of experiments can be put in agreement with the statistical formulas, and particularly the resonance measurements for slow neutrons, the evaporation spectra from medium-energy (n, n'), (p, n) and (n, p) reactions and the (n, p) cross-sections at 14 MeV. From the set of experiments discussed it is possible to obtain a consistent table of a, the parameter of the level density formula. (author)

  20. Microreactors for Studying Enantioselective Reactions

    Czech Academy of Sciences Publication Activity Database

    Pavlorková, Jana

    Prague: Faculty of Chemical Technology, ICT, 2014. [Conference of Post-graduate Students. Prague (CZ), 26.06.2014] Institutional support: RVO:67985858 Keywords : enantioselective reactions * microreactors * molecular chirality Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  1. Solar-thermal reaction processing

    Energy Technology Data Exchange (ETDEWEB)

    Weimer, Alan W; Dahl, Jaimee K; Lewandowski, Allan A; Bingham, Carl; Raska Buechler, Karen J; Grothe, Willy

    2014-03-18

    In an embodiment, a method of conducting a high temperature chemical reaction that produces hydrogen or synthesis gas is described. The high temperature chemical reaction is conducted in a reactor having at least two reactor shells, including an inner shell and an outer shell. Heat absorbing particles are included in a gas stream flowing in the inner shell. The reactor is heated at least in part by a source of concentrated sunlight. The inner shell is heated by the concentrated sunlight. The inner shell re-radiates from the inner wall and heats the heat absorbing particles in the gas stream flowing through the inner shell, and heat transfers from the heat absorbing particles to the first gas stream, thereby heating the reactants in the gas stream to a sufficiently high temperature so that the first gas stream undergoes the desired reaction(s), thereby producing hydrogen or synthesis gas in the gas stream.

  2. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  3. Enzymatic reactions in dense gases

    OpenAIRE

    Knez, Željko

    2012-01-01

    The developments on applications of supercritical fluids as alternative solvents for biocatalytic processes that have taken place over the past two decades have been reviewed. An overview of process parameters influencing enzyme activity and stability, the influence of process parameters on reaction rates and productivity are presented. Applications of various types of reactors for enzymatic reaction in dense fluids, limitations of using enzymes as biocatalyst in supercritical fluids as well ...

  4. Psychosocial reactions to physical illness.

    OpenAIRE

    Lipowski, Z J

    1983-01-01

    Recently medical educators have emphasized the need for physicians to acquire the skills to deal with psychologic aspects of patient care. To facilitate this task a descriptive schema is presented for use in evaluating patients' psychosocial reactions to physical illness. Three core components of such reactions are: the personal meaning of illness, emotional responses to illness and modes of coping with illness. Clinical application of this schema may help with patient management and prevent ...

  5. Drug Reactions in Oral Mucosa

    Directory of Open Access Journals (Sweden)

    Emine Derviş

    2012-12-01

    Full Text Available Both immunologic and nonimmunologic drug reactions can be seen in oral mucosa. Since considerable number of these reactions heals spontaneously without being noticed by the patients, exact frequency of the lesions is unknown. Most common lesions are xerostomia, taste disorders, mucosal ulcerations and edema. In this article, oral lesions resulting from drug intake similar to those from oral lesions of local and systemic diseases, and diagnostic problems caused by these similarities, have been reviewed.

  6. Spatial model of autocatalytic reactions

    OpenAIRE

    De Anna, Pietro; Di Patti, Francesca; Fanelli, Duccio; McKane, Alan J.; Dauxois, Thierry

    2010-01-01

    Biological cells with all of their surface structure and complex interior stripped away are essentially vesicles - membranes composed of lipid bilayers which form closed sacs. Vesicles are thought to be relevant as models of primitive protocells, and they could have provided the ideal environment for pre-biotic reactions to occur. In this paper, we investigate the stochastic dynamics of a set of autocatalytic reactions, within a spatially bounded domain, so as to mimic a primordial cell. The ...

  7. Consumer perceptions and reactions concerning AI

    OpenAIRE

    Figuié, Muriel; Food and Agriculture Organization of the United Nations

    2007-01-01

    This paper focuses on the results of different consumer surveys conducted between 2004 and 2006 with regard to consumers’ perceptions and reactions concerning AI in Vietnam, (mainly in Hanoi). The main results observed are as follows: A high proportion of consumers consider AI to be a food-related risk. However, over time,there has been a slight shift from a fear of consuming poultry to a fear of preparing it (slaughtering it). AI has had a profound effect on poultry consumption, even outside...

  8. Kinetics of actinide complexation reactions

    International Nuclear Information System (INIS)

    Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions

  9. Reaction mechanisms in heavy ion fusion

    Directory of Open Access Journals (Sweden)

    Lubian J.

    2011-10-01

    Full Text Available We discuss the reaction mechanisms involved in heavy ion fusion. We begin with collisions of tightly bound systems, considering three energy regimes: energies above the Coulomb barrier, energies just below the barrier and deep sub-barrier energies. We show that channel coupling effects may influence the fusion process at above-barrier energies, increasing or reducing the cross section predicted by single barrier penetration model. Below the Coulomb barrier, it enhances the cross section, and this effect increases with the system’s size. It is argued that this behavior can be traced back to the increasing importance of Coulomb coupling with the charge of the collision partners. The sharp drop of the fusion cross section observed at deep sub-barrier energies is addressed and the theoretical approaches to this phenomenon are discussed. We then consider the reaction mechanisms involved in fusion reactions of weakly bound systems, paying particular attention to the calculations of complete and incomplete fusion available in the literature.

  10. Nuclear Reactions Used For Superheavy Element Research

    Science.gov (United States)

    Stoyer, Mark A.

    2008-04-01

    Some of the most fascinating questions about the limits of nuclear stability are confronted in the heaviest nuclei. How many more new elements can be synthesized? What are the nuclear and chemical properties of these exotic nuclei? Does the "Island of Stability" exist and can we ever explore the isotopes inhabiting that nuclear region? This paper will focus on the current experimental research on the synthesis and characterization of superheavy nuclei with Z>112 from the Dubna/Livermore collaboration. Reactions using 48Ca projectiles from the U400 cyclotron and actinide targets (233,238U, 237Np, 242,244Pu, 243Am, 245,248Cm, 249Cf) have been investigated using the Dubna Gas Filled Recoil Separator in Dubna over the last 8 years. In addition, several experiments have been performed to investigate the chemical properties of some of the observed longer-lived isotopes produced in these reactions. Some comments will be made on nuclear reactions used for the production of the heaviest elements. A summary of the current status of the upper end of the chart of nuclides will be presented.

  11. Bayesian Estimation of Thermonuclear Reaction Rates

    CERN Document Server

    Iliadis, Christian; Coc, Alain; Timmes, Frank; Starrfield, Sumner

    2016-01-01

    The problem of estimating non-resonant astrophysical S-factors and thermonuclear reaction rates, based on measured nuclear cross sections, is of major interest for nuclear energy generation, neutrino physics, and element synthesis. Many different methods have been applied in the past to this problem, all of them based on traditional statistics. Bayesian methods, on the other hand, are now in widespread use in the physical sciences. In astronomy, for example, Bayesian statistics is applied to the observation of extra-solar planets, gravitational waves, and type Ia supernovae. However, nuclear physics, in particular, has been slow to adopt Bayesian methods. We present the first astrophysical S-factors and reaction rates based on Bayesian statistics. We develop a framework that incorporates robust parameter estimation, systematic effects, and non-Gaussian uncertainties in a consistent manner. The method is applied to the d(p,$\\gamma$)$^3$He, $^3$He($^3$He,2p)$^4$He, and $^3$He($\\alpha$,$\\gamma$)$^7$Be reactions,...

  12. Nuclear Reactions for Astrophysics and Other Applications

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Burke, J T; Dietrich, F S; Scielzo, N D; Ressler, J J

    2011-03-01

    Cross sections for compound-nuclear reactions are required for many applications. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  13. The severe adverse reaction to vitamin k1 injection is anaphylactoid reaction but not anaphylaxis.

    Science.gov (United States)

    Mi, Yan-Ni; Ping, Na-Na; Xiao, Xue; Zhu, Yan-Bing; Liu, Jing; Cao, Yong-Xiao

    2014-01-01

    The severe adverse reaction to vitamin K1 injection is always remarkable and is thought to result from anaphylaxis. Paradoxically, however, some patients administered vitamin K1 injection for the first time have adverse reactions. Using beagle dogs, the present study tested the hypothesis that the response to vitamin K1 is an anaphylactoid reaction. The results showed that serious anaphylaxis-like symptoms appeared in beagle dogs after the administration of vitamin K1 injection for the first time. The plasma histamine concentration increased, and blood pressure decreased sharply. After sensitization, dogs were challenged with vitamin K1 injection and displayed the same degree of symptoms as prior to sensitization. However, when the vitamin K1 injection-sensitized dogs were challenged with a vitamin K1-fat emulsion without solubilizers such asTween-80, the abnormal reactions did not occur. Furthermore, there was no significant change in the plasma immunoglobulin E concentration after vitamin K1 challenge. Following treatment with vitamin K1 injection, the release of histamine and β-hexosaminidase by rat basophilic leukemia-2H3 cells as well as the rate of apoptosis increased. The Tween-80 group displayed results similar to those observed following vitamin K1 injection in vivo. However, the dogs in the vitamin K1-fat emulsion group did not display any abnormal behavior or significant change in plasma histamine. Additionally, degranulation and apoptosis did not occur in rat basophilic leukemia-2H3 cells. Our results indicate that the adverse reaction induced by vitamin K1 injection is an anaphylactoid reaction, not anaphylaxis. Vitamin K1 injection induces the release of inflammatory factors via a non-IgE-mediated immune pathway, for which the trigger may be the solubilizer. PMID:24594861

  14. The severe adverse reaction to vitamin k1 injection is anaphylactoid reaction but not anaphylaxis.

    Directory of Open Access Journals (Sweden)

    Yan-Ni Mi

    Full Text Available The severe adverse reaction to vitamin K1 injection is always remarkable and is thought to result from anaphylaxis. Paradoxically, however, some patients administered vitamin K1 injection for the first time have adverse reactions. Using beagle dogs, the present study tested the hypothesis that the response to vitamin K1 is an anaphylactoid reaction. The results showed that serious anaphylaxis-like symptoms appeared in beagle dogs after the administration of vitamin K1 injection for the first time. The plasma histamine concentration increased, and blood pressure decreased sharply. After sensitization, dogs were challenged with vitamin K1 injection and displayed the same degree of symptoms as prior to sensitization. However, when the vitamin K1 injection-sensitized dogs were challenged with a vitamin K1-fat emulsion without solubilizers such asTween-80, the abnormal reactions did not occur. Furthermore, there was no significant change in the plasma immunoglobulin E concentration after vitamin K1 challenge. Following treatment with vitamin K1 injection, the release of histamine and β-hexosaminidase by rat basophilic leukemia-2H3 cells as well as the rate of apoptosis increased. The Tween-80 group displayed results similar to those observed following vitamin K1 injection in vivo. However, the dogs in the vitamin K1-fat emulsion group did not display any abnormal behavior or significant change in plasma histamine. Additionally, degranulation and apoptosis did not occur in rat basophilic leukemia-2H3 cells. Our results indicate that the adverse reaction induced by vitamin K1 injection is an anaphylactoid reaction, not anaphylaxis. Vitamin K1 injection induces the release of inflammatory factors via a non-IgE-mediated immune pathway, for which the trigger may be the solubilizer.

  15. Observation on the Efficacy of Small Dose of Esmolol Intravenous Pre-injection Alleviating the Reac-tion of Tracheal Intubation for Patients with Hypertension and Coronary Heart Disease%小剂量艾司洛尔预先静脉注射减轻高血压冠心病患者气管插管反应的疗效观察

    Institute of Scientific and Technical Information of China (English)

    王光福; 徐小波; 李河志; 赵辉; 刘绍靖

    2016-01-01

    目的 观察小剂量艾司洛尔预先静脉注射在减轻高血压冠心病患者气管插管反应的作用. 方法 选取2009年2月至2012年10月在武装警察部队四川总队成都医院行全身麻醉手术的高血压冠心病患者60例,根据随机数字表法分为艾司洛尔组和对照组,各30 例. 艾司洛尔组在麻醉插管前5 min给予小剂量艾司洛尔(0.7 mg/kg);对照组仅给予0.9%NaCl注射液,两组麻醉诱导和维持方法相同,分别监测并记录麻醉诱导前、诱导后、插管即刻、插管后1、3、5 min时心率和平均动脉压变化. 结果 对照组插管即刻、插管1、3、5 min 的平均动脉压较诱导前有明显升高[ ( 120 ± 15)mmHg(1 mmHg=0.133 kPa)、(118 ±23) mmHg、(115 ±10) mmHg、(112 ±14) mmHg 比(98 ± 14) mmHg],心率明显增快[(88 ±8)次/min、(94 ±15)次/min、(91 ±10)次/min、(93 ±10)次/min比(76 ±4)次/min],艾司洛尔组的平均动脉压[(101 ±11) mmHg、(104 ±18) mmHg、(101 ± 10) mmHg、(98 ±10) mmHg比(98 ±14) mmHg],心率[(78 ±4)次/min、(81 ±12)次/min、(80 ± 7)次/min、(78 ±5)次/min比(75 ±7)次/min]分别较诱导前有轻度升高,但变化幅度不大. 两组比较差异有统计学意义( P<0.05 ). 结论 小剂量艾司洛尔预先注射能够有效减轻高血压冠心病患者气管插管时的心血管反应.%Objective To observe the effect of intravenous pre-injection of small dose of esmolol on alle-viating the impact of tracheal intubation on patients with hypertension and coronary heart disease .Methods Total of 60 patients with hypertension and coronary heart disease undergoing general anesthesia operations at Chengdu Armed Police Corps Hospital from Feb.2009 to Oct.2012 were selected, and were divide into esmolol group and control group according to random number table method,with 30 patients in each group. The esmolol group was injected with small dose of esmolol(0.7 mg/kg) 5 minutes prior to the anesthetic intubation;the control

  16. Reaction rates for a generalized reaction-diffusion master equation

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2016-01-01

    It has been established that there is an inherent limit to the accuracy of the reaction-diffusion master equation. Specifically, there exists a fundamental lower bound on the mesh size, below which the accuracy deteriorates as the mesh is refined further. In this paper we extend the standard reaction-diffusion master equation to allow molecules occupying neighboring voxels to react, in contrast to the traditional approach, in which molecules react only when occupying the same voxel. We derive reaction rates, in two dimensions as well as three dimensions, to obtain an optimal match to the more fine-grained Smoluchowski model and show in two numerical examples that the extended algorithm is accurate for a wide range of mesh sizes, allowing us to simulate systems that are intractable with the standard reaction-diffusion master equation. In addition, we show that for mesh sizes above the fundamental lower limit of the standard algorithm, the generalized algorithm reduces to the standard algorithm. We derive a lower limit for the generalized algorithm which, in both two dimensions and three dimensions, is of the order of the reaction radius of a reacting pair of molecules.

  17. Biodegradable PELA block copolymers: in vitro degradation and tissue reaction.

    Science.gov (United States)

    Younes, H; Nataf, P R; Cohn, D; Appelbaum, Y J; Pizov, G; Uretzky, G

    1988-01-01

    Degradation of, and tissue reaction elicited by a series of polyethylene oxide (PEO)/polylactic acid (PLA) PELA block copolymers were studied in vitro and in vivo. In particular, the effect of pH, temperature and enzymatic activity was addressed. The mass loss was faster, the more basic the media, while, expectedly, PELA copolymers degraded faster with the higher temperature. The addition of an enzyme (carboxylic ester hydrolase) had no effect. The degradation process strongly affected the mechanical properties of the materials under investigation, the elongation at break dropping drastically after two days of degradation. After seven days, only gross observation of the extensively degraded samples was possible. The in vivo studies compared the tissue reaction elicited by various PELA copolymers to that evoked by PLA. Evaluation of tissue reaction observed with a PELA sample after sterilization with gamma radiation showed acute inflammation with considerable dispersion of the material, 12 days after implantation. The granulomatous reaction observed with PELA copolymers after ethylene oxide sterilization was identical to the reaction observed with PLA. PMID:3064826

  18. Recombination Reactions and Commissioning of DESIREE

    International Nuclear Information System (INIS)

    By combining electron scattering calculations with structure calculations molecular potential energy curves, couplings and autoionization widths are obtained. Using this molecular data the cross sections of different recombination reactions relevant for the fusion plasma of the Divertor can be calculated. Here electron-molecular ion collisions leading to either dissociative recombination, vibrational excitation (or de-excitation) or dissociative excitation have been studied. Furthermore, the believed presence of H- in the plasma is a motivation for the study of mutual neutralization in collisions between H- and light atomic cations (H+, He+, Be+). We have performed both quantum ab initio as well as semi-classical calculations on reactions involving the H2, HeH and BeH molecular systems. On H2, the focus has been on the mutual neutralization reaction in collisions of H+ and H. An fully quantum ab initio study of the reaction produce total cross section and final state distributions in good agreement with experimental studies. Additionally, the neutralization cross sections are computed for collisions between different isotopes of the hydrogen ions and a very small isotope effects are observed. Furthermore, the differential cross section of the reaction is calculated. A semi- classical Landau-Zener model is used to study the reaction. Different methods to obtain the electronic coupling elements between ionic and covalent states are examined by comparing the semiclassical results with those obtained quantum mechanically. Theoretical studies of dissociative excitation of HeH+ are performed where both the resonant and direct processes are investigated. Calculations on the non-adiabatic couplings between resonant states of HeH are under the way and goal is to perform a fully quantum ab intio study of mutual neutralization in He++H- collisions as well dissociative recombination and resonant ion-pair formation. The direct mechanism of dissociative recombination of BeH+ has

  19. Deciphering Time Scale Hierarchy in Reaction Networks.

    Science.gov (United States)

    Nagahata, Yutaka; Maeda, Satoshi; Teramoto, Hiroshi; Horiyama, Takashi; Taketsugu, Tetsuya; Komatsuzaki, Tamiki

    2016-03-01

    Markovian dynamics on complex reaction networks are one of the most intriguing subjects in a wide range of research fields including chemical reactions, biological physics, and ecology. To represent the global kinetics from one node (corresponding to a basin on an energy landscape) to another requires information on multiple pathways that directly or indirectly connect these two nodes through the entire network. In this paper we present a scheme to extract a hierarchical set of global transition states (TSs) over a discrete-time Markov chain derived from first-order rate equations. The TSs can naturally take into account the multiple pathways connecting any pair of nodes. We also propose a new type of disconnectivity graph (DG) to capture the hierarchical organization of different time scales of reactions that can capture changes in the network due to changes in the time scale of observation. The crux is the introduction of the minimum conductance cut (MCC) in graph clustering, corresponding to the dividing surface across the network having the "smallest" transition probability between two disjoint subnetworks (superbasins on the energy landscape) in the network. We present a new combinatorial search algorithm for finding this MCC. We apply our method to a reaction network of Claisen rearrangement of allyl vinyl ether that consists of 23 nodes and 66 links (saddles on the energy landscape) connecting them. We compare the kinetic properties of our DG to those of the transition matrix of the rate equations and show that our graph can properly reveal the hierarchical organization of time scales in a network. PMID:26641663

  20. Small Organic Molecules for Direct Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    TANG Zhuo; GONG Liu-Zhu; MI Ai-Qiao; JIANG Yao-Zhong

    2004-01-01

    Since the pioneering finding by List and Barbas Ⅲ and their coworkers that L-proline could work as a catalyst in the intermolecular direct aldol reaction, the concept of small organic molecules as catalysts has received great attention. However, new organic molecule which have better catalysis ability are reported scarcely.Our groups1 found L-Prolinamides 1 to be active catalysts for the direct aldol reaction of 4-nitrobenaldehyde with neat acetone at room temperature. The enantioselectivity increases as the amide N-H becomes more acidic and thus a better hydrogen bond donor. Introducing another proton donor, hydroxyl, in the catalyst lead to a further improvement in the catalytic enantioselectivity.The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity.Catalyst 2, prepared from L-proline and (1S, 2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes. It is noteworthy that our results refuted the conventional wisdom that the carboxylic acid group of proline is a reqirement for high enatioselectivity and provide a powerful strategy in the molecular design of new organic catalyst because plentiful chiral resource containing multi-hydrogen bonding donor, for example, peptides.Very recently, we found that L-proline-based peptides 3-7 can catalyze the aldol reactions of hydroxyacetone with aldehydes 8 in aqueous media, to give 1,4-diols 9, the disfavored products with either aldolase or L-proline. Both peptides 5 and 6 give good results.The abilities of peptides 5 and 6 to catalyze the direct aldol reactions of hydroxyacetone with avariety of aldehydes were examined under optimal conditions. The results are shown in table. Highyields and entioselectivities of up to 96% ee were observed for aromatic aldehydes