Sample records for autoclave curing

  1. Out-of-Autoclave Cure Composites (United States)

    Hayes, Brian S.


    As the size of aerospace composite parts exceeds that of even the largest autoclaves, the development of new out-of-autoclave processes and materials is necessary to ensure quality and performance. Many out-of-autoclave prepreg systems can produce high-quality composites initially; however, due to long layup times, the resin advancement commonly causes high void content and variations in fiber volume. Applied Poleramic, Inc. (API), developed an aerospace-grade benzoxazine matrix composite prepreg material that offers more than a year out-time at ambient conditions and provides exceptionally low void content when out-of-autoclave cured. When compared with aerospace epoxy prepreg systems, API's innovation offers significant improvements in terms of out-time at ambient temperature and the corresponding tack retention. The carbon fiber composites developed with the optimized matrix technology have significantly better mechanical performance in terms of hot-wet retention and compression when compared with aerospace epoxy matrices. These composites also offer an excellent overall balance of properties. This matrix system imparts very low cure shrinkage, low coefficient of thermal expansion, and low density when compared with most aerospace epoxy prepreg materials.

  2. Resin flow and void formation in an autoclave cure cycle (United States)

    Lionetto, Francesca; Lucia, Massimo; Dell'Anna, Riccardo; Maffezzoli, Alfonso


    A finite element (FE) model able to evaluate both the evolution of resin flow, degree of reaction and void formation during autoclave cure cycles was developed. The model was implemented using a commercial epoxy matrix widely used in aeronautic field. The FE model also included a kinetic and rheological model whose input parameters were experimentally determined by Differential Scanning Calorimetry and rheological analysis. The FE model was able to predict the evolution of degree of reaction with very good agreement with the experimental data. Moreover, the predicted resin losses were lower than 3% of the overall composite resin content.

  3. 700 F properties of autoclave cured PMR-II composites (United States)

    Cifani, Diane


    Studies were conducted to develop autoclave processing parameters for graphite reinforced PMR-2 resin composite materials intended for use in applications at temperatures up to 371 degrees (700 F). The effect of resin composition on autoclaveability was investigated. The effect of various graphite fibers and resin composition on 343 C (650 F) and 371 C (700 F) thermo-oxidative stability and mechanical properties was also investigated. The results of the processing studies show that PMR-2 resin composites can be easily fabricated under autoclave conditions. Autoclaved laminates exposed to 1 atm of air at 343 C (650 F) and 371 C (700 F) exhibited less than 5 percent weight loss after 750 hr exposure to 650 F air and 8 percent weight loss during exposure to 700 F air for 500 hr. After 500 hr exposure, autoclaved laminates exhibited greater than 90 percent retention of initial 650 and 700 F flexural and interlaminar shear strengths. The effect of resin formulated molecular weight and postcure conditions on laminate glass transition temperature is also discussed.

  4. The 700 F properties of autoclave cured PMR-2 composites (United States)

    Vannucci, Raymond D.; Cifani, Diane


    Studies were conducted to develop autoclave processing parameters for graphite reinforced PMR-2 resin composite materials intended for use in applications at temperatures up to 371 degrees (700 F). The effect of resin composition on autoclaveability was investigated. The effect of various graphite fibers and resin composition on 343 C (650 F) and 371 C (700 F) thermo-oxidative stability and mechanical properties was also investigated. The results of the processing studies show that PMR-2 resin composites can be easily fabricated under autoclave conditions. Autoclaved laminates exposed to 1 atm of air at 343 C (650 F) and 371 C (700 F) exhibited less than 5 percent weight loss after 750 hr exposure to 650 F air and 8 percent weight loss during exposure to 700 F air for 500 hr. After 500 hr exposure, autoclaved laminates exhibited greater than 90 percent retention of initial 650 and 700 F flexural and interlaminar shear strengths. The effect of resin formulated molecular weight and postcure conditions on laminate glass transition temperature is also discussed.

  5. Mathematical Model For Autoclave Curing Of Unsaturated Polyester Based Composite Materials

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    Adnan A. Abdul Razak


    Full Text Available Heat transfer process involved in the autoclave curing of fiber-reinforced thermosetting composites is investigated numerically. A model for the prediction of the temperature and the extent of the reaction across the laminate thickness during curing process in the autoclave of unsaturated polyester based composite has been developed. The governing equation for one dimensional heat transfer, and accounting for the heat generation due to the exothermic cure reaction in the composites had been used.  It was found that the temperature at the central of the laminate increases up to the external imposed temperature, because of the thermal conductivity of the resin and fiber. The heat generated by the exothermic reaction of the resin is not adequately removed; the increase in the temperature at the center increases the resins rate reaction, which in turn generates more heat.

  6. Curing Pressure Influence of Out-of-Autoclave Processing on Structural Composites for Commercial Aviation

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    Vasileios M. Drakonakis


    Full Text Available Autoclaving is a process that ensures the highest quality of carbon fiber reinforced polymer (CFRP composite structures used in aviation. During the autoclave process, consolidation of prepreg laminas through simultaneous elevated pressure and temperature results in a uniform high-end material system. This work focuses on analyzing in a fundamental way the applications of pressure and temperature separately during prepreg consolidation. A controlled pressure vessel (press-clave has been designed that applies pressure during the curing process while the temperature is being applied locally by heat blankets. This vessel gives the ability to design manufacturing processes with different pressures while applying temperature at desired regions of the composite. The pressure role on the curing extent and its effect on the interlayer region are also tested in order to evaluate the consolidation of prepregs to a completely uniform material. Such studies may also be used to provide insight into the morphology of interlayer reinforcement concepts, which are widely used in the featherweight composites. Specimens manufactured by press-clave, which separates pressure from heat, are analytically tested and compared to autoclaved specimens in order to demonstrate the suitability of the press-clave to manufacture high-quality composites with excessively reduced cost.

  7. [Methods Used for Monitoring Cure Reactions in Real-time in an Autoclave (United States)

    Cooper, John B.; Wise, Kent L.; Jensen, Brian J. (Technical Monitor)


    The goal of the research was to investigate methods for monitoring cure reactions in real-time in an autoclave. This is of particular importance to NASA Langley Research Center because polyimides were proposed for use in the High Speed Civil Transport (HSCT) program. Understanding the cure chemistry behind the polyimides would allow for intelligent processing of the composites made from their use. This work has led to two publications in peer-reviewed journals and a patent. The journal articles are listed as Appendix A which is on the instrument design of the research and Appendix B which is on the cure chemistry. Also, a patent has been awarded for the instrumental design developed under this grant which is given as Appendix C. There has been a significant amount of research directed at developing methods for monitoring cure reactions in real-time within the autoclave. The various research efforts can be categorized as methods providing either direct chemical bonding information or methods that provide indirect chemical bonding information. Methods falling into the latter category are fluorescence, dielectric loss, ultrasonic and similar type methods. Correlation of such measurements with the underlying chemistry is often quite difficult since these techniques do not allow monitoring of the curing chemistry which is ultimately responsible for material properties. Direct methods such as vibrational spectroscopy, however, can often be easily correlated with the underlying chemistry of a reaction. Such methods include Raman spectroscopy, mid-IR absorbance, and near-IR absorbance. With the recent advances in fiber-optics, these spectroscopic techniques can be applied to remote on-line monitoring.

  8. Monitoring cure properties of out-of-autoclave BMI composites using IFPI sensor (United States)

    Kaur, Amardeep; Anandan, Sudharshan; Yuan, Lei; Watkins, Steve E.; Chandrashekhara, K.; Xiao, Hai; Phan, Nam


    A non-destructive technique for inspection of a Bismaleimide (BMI) composite is presented using an optical fiber sensor. High performance BMI composites are used for Aerospace application for their mechanical strength. They are also used as an alternative to toughened epoxy resins. A femtosecond-laser-inscribed Intrinsic Fabry-Perot Interferometer (IFPI) sensor is used to perform real time cure monitoring of a BMI composite. The composite is cured using the out-of-autoclave (OOA) process. The IFPI sensor was used for in-situ monitoring; different curing stages are analyzed throughout the curing process. Temperature-induced-strain was measured to analyze the cure properties. The IFPI structure comprises of two reflecting mirrors inscribed on the core of the fiber using a femtosecond-laser manufacturing process. The manufacturing process makes the sensor thermally stable and robust for embedded applications. The sensor can withstand very high temperatures of up to 850 °C. The temperature and strain sensitivities of embedded IFPI sensor were measured to be 1.4 pm/μepsilon and 0.6 pm/μepsilon respectively.

  9. An Investigation of Steam Curing Pressure Effect on Pozzolan Additive Autoclaved Aerated Concrete

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    Kadir Güçlüer


    Full Text Available Autoclaved Aerated Concrete (AAC is a porous light weight concrete obtained by adding a pore-forming material to a mixture made of finely pulverized siliceous aggregate and inorganic binder (lime and/or cement and hardened by steam cure. In this study fly ash was used instead of siliceous aggregate and experiment samples were obtained by adding 3%, 6%, 9%, 12% silica fume to the cement. Samples were cured under 1560C and 4 bars and 1770C and 8 bars, and were investigated for compressive strength, bulk density and ultrasound pulse velocity to determine their mechanical and physical properties. Microstructure of samples was observed by using SEM and XRD techniques. Samples’ bulk density values and compressive strengths are changing between 0.6-0.7 kg/dm3 and 2.5-4.4 MPa respectively.

  10. Experimental Study of Monitoring and Controlling of Composite Cure Process in Autoclave Featured with Fiber Optic Sensor

    Institute of Scientific and Technical Information of China (English)


    With the aid of the latest fiber optic sensing technology, parameters in the cure process of thermosetting resin-matrix composite, such as temperature, viscosity, void and residual stress, can be monitored entirely and efficiently. In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology,the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.

  11. Relationship between Structural Characteristics of Fly Ash and Reactivity under Autoclave Curing

    Institute of Scientific and Technical Information of China (English)


    The reactivity of autoclaved materials is conventionally estimated by their chemical composition. In this paper, after determining the chemical composition of various types of fly ash, a series of new tests which included X-ray Diffraction (XRD), infrared spectral analysis (IR) and bound water testing, were applied to investigate the performance of autoclaved fly ash products. The relationship between the infrared spectral analysis of Si-O wavenumber (about 1 100 cm-1) and its autoclaved chemical reactivity, and compressive strength of its autoclaved samples, is analyzed. The results show that fly ash with a lower wavenumber will have stronger autoclaved chemical reactivity and higher compressive strength for its autoclaved sample. Thus, the Si-O stretching vibration wavelength can be used to estimate autoclaved chemical reactivity of fly ash, so as to control the quality of fly ash to be autoclaved, and to predict the compressive strength of autoclaved fly ash products.

  12. Long Out-time, Out-of-Autoclave Cure Composites Project (United States)

    National Aeronautics and Space Administration — As the size of composite parts exceed that of even the largest autoclaves, new out-of-autoclave processes and materials are necessary to achieve the same level of...

  13. Mechanical Characterization of In and Out-of-Autoclave Cured Composite Panels for Large Launch Vehicles (United States)

    Kellas, Sotiris; Lerch, Bradley A.; Wilmoth, Nathan


    Two manufacturing demonstration panels (1/16th-arc-segments of 10 m diameter cylinder) were fabricated under the composites part of the Lightweight Space Structures and Materials program. Both panels were of sandwich construction with aluminum core and 8-ply quasi-isotropic graphite/epoxy facesheets. One of the panels was constructed with in-autoclave curable unidirectional prepreg (IM7/977-3) and the second with out-of-autoclave unidirectional prepreg (T40-800B/5320-1). Following NDE inspection, each panel was divided into a number of small specimens for material property characterization and a large (0.914 m wide by 1.524 m long) panel for a buckling study. Results from the small specimen tests were used to (a) assess the fabrication quality of each 1/16th arc segment panel and (b) to develop and/or verify basic material property inputs to Finite Element analysis models. The mechanical performance of the two material systems is assessed at the coupon level by comparing average measured properties such as flatwise tension, edgewise compression, and facesheet tension. The buckling response of the 0.914 m wide by 1.524 m long panel provided a comparison between the in- and out-of autoclave systems at a larger scale.

  14. An Investigation of Stimulating the Autoclave Curing Process of Resin Matrix/Fiber Reinforced Composite Material,Ⅰ: Process model

    Institute of Scientific and Technical Information of China (English)


    A mathematical model is made which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the composite is developed. The model provides the variation of temperature distribution, the cure reaction process in the resin, the resin flow and fibers stress inside the composite, and the void variation and the residual stress distribution. It can be used to illustrate the mechanism of curing process and optimize the cure cycle of composite material in order to ensure the quality of a product.

  15. Effect of Steam-Autoclaved Curing on Chloride Permeability of High Strength Concrete%二次高温养护对高强混凝土抗 Cl-渗透性的影响

    Institute of Scientific and Technical Information of China (English)

    刘东升; 朱建舟; 谭克锋


    利用氯离子快速渗透法(RCM)研究了普通蒸汽养护后(80℃,0.1 MPa)再进行压蒸(180℃,1 MPa)养护,即二次高温养护,对不同胶凝材料体系的高强混凝土抗Cl-渗透性的影响。结果表明:对于纯水泥混凝土,与标养相比,“蒸养-压蒸”养护使混凝土抗Cl -渗透性能劣化。掺入粉煤灰、矿粉以及硅灰以等比例取代水泥时,“蒸养-压蒸”都较为充分地激发了上述混合材的火山灰活性,但不同掺合料对“蒸养-压蒸”后高强混凝土抗Cl-渗透性能影响差别较大。 XRD和SEM研究表明上述结果的产生与高温下水化产物的种类和分布有关。%Rapid choloride migration test (RCMT) was used to investigate the influence of curing methods and mineral admixtures on chloride ingress resistance of high strength concrete .The results indicate that steam cu-ring and autoclaving curing , especially autoclaving curing , considerably aggravated the chloride penetration through pure cement concrete when compared with normal curing .Incorporating silica fume can improve the chloride ingress resistance of steam curing concrete but degrades autoclaving curing concrete .Adding fly ash with low pozzolanic activity can increase chloride ingress resistance of autoclaving curing concrete , while chlo-ride penetration resistance of steam curing concrete becomes lower .The measure of multi-elements mineral admixtures mixing is propitious to improving the chloride ingress resistance of concrete compared with pure ce-ment concrete under same curing conditions .Results above was analyzed by XRD and SEM .

  16. Fast estimating concrete strength method applying microwave autoclave curing technology%应用微波蒸压技术的混凝土强度快速测定方法

    Institute of Scientific and Technical Information of China (English)

    蒋德稳; 田安国; 胡杰; 赵政


    为了快速测定混凝土强度,将微波技术应用到传统的蒸压养护工艺中,自行设计和制作了小型微波蒸压釜。通过试验得出了釜腔内温度压力大小、恒温恒压养护时间对混凝土早期强度的影响规律,进而总结出微波蒸压养护条件下混凝土快速养护制度。通过15批次(5种配合比)不同强度等级混凝土的微波蒸压养护和标准养护对比试验,建立了微波蒸压养护条件下的混凝土强度线性和非线性回归模型,模型中考虑了加速养护混凝土强度和混凝土水灰比,具有较好的相关关系。试验分析发现:运用微波技术,可以均匀、迅速地提高混凝土内部温度,减小温度应力,使混凝土1 h内获得较高(28 d强度40%~50%)、稳定的早期强度,可以作为预拌混凝土生产企业和施工现场进行强度控制和配合比调整时的依据。%In order to estimate concrete strength quickly,microwave was applied to the conditional autoclave curing. Small microwave autoclave suitable for the microwave autoclaved were self designed and made. By experiment research,the effect laws of temperature in autoclave and constant temperature curing time on the early strength of concrete were investigated,and rapid curing system was summa-rized on the condition of microwave and autoclave. By the contrast test of microwave autoclave curing and standard curing of 15 batches of different strength grade concrete,the linear and nonlinear regression model of concrete strength determination were established with better correlativity on the condition of microwave and autoclave. Concrete strength accelerated of curing and water-cement-ratio was considered in the model. It was found that the internal temperature of concrete would be uniformly,rapidly improved by microwave,and the temperature stress would be reduced.The high and stable early strength of concrete(40~50 percent of 28 d strength)was obtained

  17. Polimerização complementar em autoclave, microondas e estufa de um compósito restaurador direto = The effect of post-cure heating in autoclave, microwave oven and conventional oven on direct composite resin

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    Arossi, Guilherme Anziliero


    Full Text Available Com o objetivo de tornar o processo de confecção de restaurações indiretas mais acessível, reduzindo seus custos com a resina utilizada e os métodos de polimerização complementar, este estudo testou a possibilidade de se utilizar resinas diretas com métodos de polimerização complementar alternativos. Corpos de prova foram confeccionados com a resina Charisma e fotopolimerizados por 20 segundos. Em seguida as amostras foram submetidas à polimerização complementar em autoclave, microondas e estufa. Foram estabelecidos dois grupos controles: um controle negativo, que consistiu na utilização da resina Charisma fotopolimerizada convencionalmente (20s; e um grupo controle positivo, formado por amostras do compósito restaurador indireto Targis. O ensaio de microdureza Knoop foi realizado após uma semana de armazenagem e os resultados submetidos à análise estatística. Os três métodos de polimerização complementar propostos determinaram um aumento na microdureza do compósito restaurador direto quando comparado ao controle negativo (p 0,05. Conclui-se que, considerando o desenho experimental deste estudo, a polimerização complementar em autoclave, microondas ou estufa aumenta a microdureza da resina Charisma previamente fotopolimerizada

  18. Optimal Composite Curing System (United States)

    Handel, Paul; Guerin, Daniel

    The Optimal Composite Curing System (OCCS) is an intelligent control system which incorporates heat transfer and resin kinetic models coupled with expert knowledge. It controls the curing of epoxy impregnated composites, preventing part overheating while maintaining maximum cure heatup rate. This results in a significant reduction in total cure time over standard methods. The system uses a cure process model, operating in real-time, to determine optimal cure profiles for tool/part configurations of varying thermal characteristics. These profiles indicate the heating and cooling necessary to insure a complete cure of each part in the autoclave in the minimum amount of time. The system coordinates these profiles to determine an optimal cure profile for a batch of thermally variant parts. Using process specified rules for proper autoclave operation, OCCS automatically controls the cure process, implementing the prescribed cure while monitoring the operation of the autoclave equipment.

  19. Manufacturing and Shear Response Characterization of Carbon Nanofiber Modified CFRP Using the Out-of-Autoclave-Vacuum-Bag-Only Cure Process

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    Erin E. McDonald


    Full Text Available The interlaminar shear response is studied for carbon nanofiber (CNF modified out-of-autoclave-vacuum-bag-only (OOA-VBO carbon fiber reinforced plastic (CFRP. Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testingwas used to study the in-plane shear performance of [±45°]4s composite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination.

  20. Manufacturing and shear response characterization of carbon nanofiber modified CFRP using the out-of-autoclave-vacuum-bag-only cure process. (United States)

    McDonald, Erin E; Wallace, Landon F; Hickman, Gregory J S; Hsiao, Kuang-Ting


    The interlaminar shear response is studied for carbon nanofiber (CNF) modified out-of-autoclave-vacuum-bag-only (OOA-VBO) carbon fiber reinforced plastic (CFRP). Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testing was used to study the in-plane shear performance of [± 45°]4s composite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC) surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination.

  1. Mechanical Properties of Autoclaved Shell-aggregate

    Institute of Scientific and Technical Information of China (English)

    MA Hailong; CUI Chong; LI Xing; Pierre Chevrier; Vanessa Bouchart; TANG Feng


    Waste solid propylene oxide sludge(POS)and fly ash were used as main raw material to prepare propylene oxide sludge aggregate(POSA)under the condition of autoclaved(180 ℃,1.0 MPa)curing.Three different test methods namely cylinder compressive strength(CCS),individual aggregate compressive strength(IACS)and strength contribution rate(SCR)proposed were used to characterize the mechanical properties of the autoclaved POSA.POS shell-aggregate with SCR of 94% were prepared under the hydrothermal synthesis and autoclaved curing.The experimental results indicate that CCS and IACS have good consistency in characterizing mechanical properties of POSA.It is suggested that SCR not only can characterize the strength of POSA core,but also can reflect the effect of shell on the performance of POSA.By means of least square method,relationships between CCS and IACS,CCS and SCR,IACS and SCR were deduced.

  2. BALU: Largest autoclave research facility in the world

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    Hakan Ucan


    Full Text Available Among the large-scale facilities operated at the Center for Lightweight-Production-Technology of the German Aerospace Center in Stade BALU is the world's largest research autoclave. With a loading length of 20m and a loading diameter of 5.8 m the main objective of the facility is the optimization of the curing process operated by components made of carbon fiber on an industrial scale. For this reason, a novel dynamic autoclaving control has been developed that is characterized by peripheral devices to expend the performance of the facility for differential applications, by sensing systems to detect the component state throughout the curing process and by a feedback system, which is capable to intervene into the running autoclave process.

  3. Autoclave nuclear criticality safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    D`Aquila, D.M. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States); Tayloe, R.W. Jr. [Battelle, Columbus, OH (United States)


    Steam-heated autoclaves are used in gaseous diffusion uranium enrichment plants to heat large cylinders of UF{sub 6}. Nuclear criticality safety for these autoclaves is evaluated. To enhance criticality safety, systems are incorporated into the design of autoclaves to limit the amount of water present. These safety systems also increase the likelihood that any UF{sub 6} inadvertently released from a cylinder into an autoclave is not released to the environment. Up to 140 pounds of water can be held up in large autoclaves. This mass of water is sufficient to support a nuclear criticality when optimally combined with 125 pounds of UF{sub 6} enriched to 5 percent U{sup 235}. However, water in autoclaves is widely dispersed as condensed droplets and vapor, and is extremely unlikely to form a critical configuration with released UF{sub 6}.

  4. Comparison of Autoclave and Out-of-Autoclave Composites (United States)

    Sutter, James K.; Kenner, W. Scott; Pelham, Larry; Miller, Sandi G.; Polis, Danel L.; Nailadi, Chaitra; Zimmerman, Thomas J.; Lort, Richard D.; Hou, Tan-Hung; Quade, Derek J.; Lerch, Bradley A.; Walker, James; Fikes, John


    The National Aeronautics and Space Administration (NASA) Exploration Systems Mission Directorate initiated an Advanced Composite Technology Project through the Exploration Technology Development Program in order to support the polymer composite needs for future heavy lift launch architectures. As an example, the large composite dry structural applications on Ares V inspired the evaluation of autoclave and out-of-autoclave (OOA) composite materials. A NASA and industry team selected the most appropriate materials based on component requirements for a heavy lift launch vehicle. Autoclaved and OOA composites were fabricated and results will highlight differences in processing conditions, laminate quality, as well as initial room temperature thermal and mechanical performance. Results from this study compare solid laminates that were both fiber-placed and hand-laid. Due to the large size of heavy-lift launch vehicle composite structures, there is significant potential that the uncured composite material or prepreg will experience significant out-life during component fabrication. Therefore, prepreg out-life was a critical factor examined in this comparison. In order to rigorously test material suppliers recommended out-life, the NASA/Industry team extended the out-time of the uncured composite prepreg to values that were approximately 50% beyond the manufacturers out-time limits. Early results indicate that the OOA prepreg composite materials suffered in both composite quality and mechanical property performance from their extended out-time. However, the OOA materials performed similarly to the autoclaved composites when processed within a few days of exposure to ambient "shop" floor handling. Follow on studies evaluating autoclave and OOA aluminum honeycomb core sandwich composites are planned.

  5. Out of the Autoclave Fabrication of LaRC[TradeMark] PETI-9 Polyimide Laminates (United States)

    Cano, Robert J.; Jensen, Brian J.


    The NASA Langley Research Center developed polyimide system, LaRC PETI-9, has successfully been processed into composites by high temperature vacuum assisted resin transfer molding (HT-VARTM). To extend the application of this high use temperature material to other out-of-autoclave (OOA) processing techniques, the fabrication of PETI- 9 laminates was evaluated using only a vacuum bag and oven cure. A LaRC PETI-9 polyimide solution in NMP was prepared and successfully utilized to fabricate unidirectional IM7 carbon fiber prepreg that was subsequently processed into composites with a vacuum bag and oven cure OOA process. Composite panels of good quality were successfully fabricated and mechanically tested. Processing characteristics, composite panel quality and mechanical properties are presented in this work. The resultant properties are compared to previously developed LaRC material systems processed by both autoclave and OOA techniques including the well characterized, autoclave processed LaRC PETI-5.

  6. No-Oven, No-Autoclave Composite Processing (United States)

    Rauscher, Michael D.


    Very large composite structures, such as those used in NASA's Space Launch System, push the boundaries imposed by current autoclaves. New technology is needed to maintain composite performance and free manufacturing engineers from the restraints of curing equipment size limitations. Recent efforts on a Phase II project by Cornerstone Research Group, Inc. (CRG), have advanced the technology and manufacturing readiness levels of a unique two-part epoxy resin system. Designed for room-temperature infusion of a dry carbon preform, the system includes a no-heat-added cure that delivers 350 F composite performance in a matter of hours. This no-oven, no-autoclave (NONA) composite processing eliminates part-size constraints imposed by infrastructure and lowers costs by increasing throughput and reducing capital-specific, process-flow bottlenecks. As a result of the Phase II activity, NONA materials and processes were used to make high-temperature composite tooling suitable for further production of carbon-epoxy laminates and honeycomb/ sandwich-structure composites with an aluminum core. The technology platform involves tooling design, resin infusion processing, composite part design, and resin chemistry. The various technology elements are combined to achieve a fully cured part. The individual elements are not unusual, but they are combined in such a way that enables proper management of the heat generated by the epoxy resin during cure. The result is a self-cured carbon/ epoxy composite part that is mechanically and chemically stable at temperatures up to 350 F. As a result of the successful SBIR effort, CRG has launched NONA Composites as a spinoff subsidiary. The company sells resin to end users, fabricates finished goods for customers, and sells composite tooling made with NONA materials and processes to composite manufacturers.

  7. Volume of an Industrial Autoclave

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    Nicholas Madaffari


    Full Text Available We were able to determine the volume of an industrial autoclave sterilization tank using a technique learned in calculus. By measuring the dimensions of the tank and roughly estimating the equation of curvature at the ends of the tank, we were able to revolve half of the end of the tank around the x axis to get its fluid volume. Adding the two volumes of the ends and the volume of the cylindrical portion on the tank yielded the total volume.

  8. Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition. (United States)

    Kikuma, Jun; Tsunashima, Masamichi; Ishikawa, Tetsuji; Matsuno, Shin-ya; Ogawa, Akihiro; Matsui, Kunio; Sato, Masugu


    Hydrothermal formation of tobermorite from a pre-cured cake has been investigated by transmission X-ray diffraction (XRD) using high-energy X-rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide-angle X-ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non-crystalline C-S-H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures.

  9. Mercury release during autoclave sterilization of amalgam. (United States)

    Parsell, D E; Karns, L; Buchanan, W T; Johnson, R B


    Natural teeth are an invaluable teaching tool for preclinical instruction in operative dentistry and endodontic techniques. Cavity preparation in teeth containing amalgam restorations is a realistic simulation of an often experienced clinical situation. As various pathogens are contained in saliva, teeth must be disinfected before use by students. The purpose of this study is to indirectly evaluate whether mercury vapor is released from amalgam restorations in such teeth during steam autoclave sterilization. Mercury vapor detection, sample mass changes and x-ray fluorescence data were collected from experimental steam autoclave sterilization of amalgam samples sealed in autoclave bags. All of the data showed evidence of mercury vapor generation coincident to steam autoclave sterilization. Mercury vapor levels within the room where amalgam was exposed to steam autoclave sterilization reached levels that constitute an unnecessary health risk to dental personnel. The volume of amalgam tested simulated that contained in 175 amalgam restored teeth. Initial venting of the autoclave chamber produced mercury vapor concentrations significantly in excess of OSHA vapor concentration ceiling levels. Thus, the use of a steam autoclave for sterilization of amalgam containing teeth for use in preclinical laboratory exercises may be harmful to personnel involved.

  10. Face-Sheet Quality Analysis and Thermo-Physical Property Characterization of OOA and Autoclave Panels (United States)

    Miller, Sandi G.; Lort, Richard D., III; Zimmerman, Thomas J.; Sutter, James K.; Pelham, Larry I.; McCorkle, Linda S.; Scheiman, Daniel A.


    Increased application of polymer matrix composite (PMC) materials in large vehicle structures requires consideration of non-autoclave manufacturing technology. The NASA Composites for Exploration project, and its predecessor, Lightweight Spacecraft Structures and Materials project, were tasked with the development of materials and manufacturing processes for structures that will perform in a heavy-lift-launch vehicle environment. Both autoclave and out of autoclave processable materials were considered. Large PMC structures envisioned for such a vehicle included the payload shroud and the interstage connector. In this study, composite sandwich panels representing 1/16th segments of the barrel section of the Ares V rocket fairing were prepared as 1.8 m x 2.4 m sections of the 10 m diameter arc segment. IM7/977-3 was used as the face-sheet prepreg of the autoclave processed panels and T40-800B/5320-1 for the out of autoclave panels. The core was 49.7 kg/sq m (3.1 lb/cu ft (pcf)) aluminum honeycomb. Face-sheets were fabricated by automated tape laying 153 mm wide unidirectional tape. This work details analysis of the manufactured panels where face-sheet quality was characterized by optical microscopy, cured ply thickness measurements, acid digestion, and thermal analysis.

  11. Autoclave foam concrete: Structure and properties (United States)

    Mestnikov, Alexei; Semenov, Semen; Strokova, Valeria; Nelubova, Viktoria


    This paper describes the technology and properties of autoclaved foam concrete taking into account practical experience and laboratory studies. The results of study of raw materials and analysis of structure and properties of foam-concrete before and after autoclave treatment are basic in this work. Experimental studies of structure and properties of foam concrete are carried out according to up-to-date methods and equipment on the base of the shared knowledge centers. Results of experimental studies give a deep understanding of properties of raw materials, possible changes and new formations in inner layers of porous material providing the improvement of constructional and operational properties of autoclaved foam concrete. Principal directions of technology enhancement as well as developing of production of autoclave foam concretes under cold-weather conditions in Russia climate are justified.

  12. A compensation approach to the tool used in autoclave based on FEA

    Institute of Scientific and Technical Information of China (English)

    Zhang Ji; Li Yingguang; Li Nanya; and Liao Wenhe


    Optimization of the curing process can not control the deformation of composite part prepared in autoclave accurately. And traditional "trial-and-error" tool surface compensation approach is low efficiency, high cost and can not control part deformation quantificationally. In order to address these issues, tool compensation approach based on FEA is presented. Model of multi-field coupling relationship in autoclave is realized. And finite element analysis model of composite part's curing process is developed to analyze part deformation. According to displacement of the part surface nodes after deformation, tool surface which compensated by the displacement of composite part which analyzed by FEA is used to control part deformation. A cylindrical composite part is ana- lyzed to verify the approach, and the result proves the correctness and validity of the approach.


    Directory of Open Access Journals (Sweden)

    V. N. Yaglov


    Full Text Available The paper proposes a technology for obtaining bricks on the basis of lime-silica mixtures where chemical interactions are practically completely realized in dispersive state at the stage of preparation of binding contact maturing and raw mixture as a whole. The role of forming operation (moulding is changed in principle because in this case conversion of dispersive system into a rock-like solid occurs and due to this the solid obtains complete water-resistance in contact with water immediately after forming operation. Theoretical basis for the developed technology is capability of silicate dispersive substances (hydrated calcium silicate to transit in non-stable state, to form a rock-like water-resistant solid in the moment of mechanical load application during forming process. Specific feature of the proposed method is an exclusion of additional operations for autoclaving of products from the process of obtaining a silicate brick.Synthetic hydrated calcium silicate in contrast to natural ones are more uniform in composition and structure, they contain less impurities and they are characterized by dispersive composition and due to the mentioned advantages they find wider practical application. Contact-condensation binders permit to manipulate product properties on their basis and ensure maximum correspondence to the requirements of the concrete application. Raw material sources for obtaining synthetic hydrated calcium silicates are practically un-limited because calcium-silicon containing substances are found as in various technogenic wastes so in natural compounds as well. So the problem for obtaining hydrated calcium silicates having contact-condensation ability for structure formation becomes more and more actual one. This transition is considered as dependent principally on arrangement rate of substance particles which determined the level of its instability.

  14. Autoclave performance and operator knowledge of autoclave use in primary care: a survey of UK practices. (United States)

    Coulter, W A; Chew-Graham, C A; Cheung, S W; Burke, F J


    Changes in the delivery of health care have increased the demand for minor surgical and screening procedures in general practice. This has increased the risk of cross-infection with blood-borne viruses and the demand for sterile instruments. The aim of this study was to investigate the knowledge and training of medical personnel in England and Wales on aspects of autoclave use, and to test the effectiveness of their practice autoclaves. An anonymous postal questionnaire and autoclave performance survey using biological indicators was made of 700 general medical practitioners selected at random from FHSA lists from 12 Health Authorities in England and Wales. The overall response rate was 53.1% (N= 372) comprising 10% general practitioners and 90% practice nurses. Eighty-two percent of respondents used autoclaves with a mean age of 2.5 years, of which 91% had been serviced in the past year. While 35% of respondents made daily observation of gauges, 19% did not routinely monitor autoclave effectiveness. Six autoclaves failed to sterilize the spore test ampoules. Fourteen percent of respondents did not autoclave instruments after every patient. Only 33.1% reported wearing gloves during minor operations. Fifty five percent had training in cross-infection prevention. It was concluded that although there has been improvement in instrument decontamination procedures in general practice compared with previous surveys, further education of medical practitioners and practice nurses in the use of autoclaves and infection prevention and control is indicated. The failure of 2% of the autoclaves to kill spores suggests the need for increased monitoring of autoclave performance. Two-thirds of practitioners exposed themselves to increased risk of infection by carrying out minor surgery without the protection of gloves.

  15. Intelligent sensor-model automated control of PMR-15 autoclave processing (United States)

    Hart, S.; Kranbuehl, D.; Loos, A.; Hinds, B.; Koury, J.


    An intelligent sensor model system has been built and used for automated control of the PMR-15 cure process in the autoclave. The system uses frequency-dependent FM sensing (FDEMS), the Loos processing model, and the Air Force QPAL intelligent software shell. The Loos model is used to predict and optimize the cure process including the time-temperature dependence of the extent of reaction, flow, and part consolidation. The FDEMS sensing system in turn monitors, in situ, the removal of solvent, changes in the viscosity, reaction advancement and cure completion in the mold continuously throughout the processing cycle. The sensor information is compared with the optimum processing conditions from the model. The QPAL composite cure control system allows comparison of the sensor monitoring with the model predictions to be broken down into a series of discrete steps and provides a language for making decisions on what to do next regarding time-temperature and pressure.

  16. Effect of In-Situ Curing on Compressive Strength of Reactive Powder Concrete


    Bali Ika; Kushartomo Widodo; Jonathan


    A development of Reactive Powder Concrete (RPC) currently is the use of quartz powder as a stabilizing agent with the content to cement ratio of 30% and steam curing method in an autoclave temperature of 250ºC which produced a high compressive strength of 180 MPa. That RPC can be generated due to one reason for using the technique of steam curing in an autoclave in the laboratory. This study proposes in-situ curing method in order the curing can be applied in the field and with a reasonable c...

  17. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas


    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  18. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads (United States)

    Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.


    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  19. Critical parameters for electron beam curing of cationic epoxies and property comparison of electron beam cured cationic epoxies versus thermal cured resins and composites

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C.J.; Norris, R.E.; Yarborough, K. [Oak Ridge National Lab., TN (United States). Oak Ridge Centers for Manufacturing Technology; Havens, S.J. [Oak Ridge Inst. for Science and Education, TN (United States); Lopata, V.J. [Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada). Whiteshell Labs.


    Electron beam curing of composites is a nonthermal, nonautoclave curing process offering the following advantages compared to conventional thermal curing: substantially reduced manufacturing costs and curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvements in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance electron beam curing of composites. The CRADA has successfully developed hundreds of new toughened and untoughened resins, offering unlimited formulation and processing flexibility. Several patent applications have been filed for this work. Composites made from these easily processable, low shrinkage material match the performance of thermal cured composites and exhibit: low void contents comparable to autoclave cured composites (less than 1%); superb low water absorption values in the same range as cyanate esters (less than 1%); glass transition temperatures rivaling those of polyimides (greater than 390 C); mechanical properties comparable to high performance, autoclave cured composites; and excellent property retention after cryogenic and thermal cycling. These materials have been used to manufacture many composite parts using various fabrication processes including hand lay-up, tow placement, filament winding, resin transfer molding and vacuum assisted resin transfer molding.

  20. Cure SMA (United States)

    ... SMA Europe and TREAT-NMD for Meeting with EMA Regulators Cure SMA will be participating in a one-day workshop with The European Medicines Agency (EMA—the European equivalent of the FDA), SMA... READ ...

  1. Elevated Temperature, Residual Compressive Strength of Impact-Damaged Sandwich Structure Manufactured Out-of-Autoclave (United States)

    Grimsley, Brian W.; Sutter, James K.; Burke, Eric R.; Dixon, Genevieve D.; Gyekenyesi, Thomas G.; Smeltzer, Stanley S.


    Several 1/16th-scale curved sandwich composite panel sections of a 10 m diameter barrel were fabricated to demonstrate the manufacturability of large-scale curved sections using minimum gauge, [+60/-60/0]s, toughened epoxy composite facesheets co-cured with low density (50 kilograms per cubic meters) aluminum honeycomb core. One of these panels was fabricated out of autoclave (OoA) by the vacuum bag oven (VBO) process using Cycom(Registered Trademark) T40-800b/5320-1 prepreg system while another panel with the same lay-up and dimensions was fabricated using the autoclave-cure, toughened epoxy prepreg system Cycom(Registered Trademark) IM7/977-3. The resulting 2.44 m x 2 m curved panels were investigated by non-destructive evaluation (NDE) at NASA Langley Research Center (NASA LaRC) to determine initial fabrication quality and then cut into smaller coupons for elevated temperature wet (ETW) mechanical property characterization. Mechanical property characterization of the sandwich coupons was conducted including edge-wise compression (EWC), and compression-after-impact (CAI) at conditions ranging from 25 C/dry to 150 C/wet. The details and results of this characterization effort are presented in this paper.

  2. Process For Autoclaving HMW PMR-II Composites (United States)

    Vannucci, Raymond D.; Cifani, Diane


    Parts made of graphite-reinforced, high-molecular-weight (HMW) PMR-II polyimide easy to fabricate by autoclaving. Study showed autoclaved HMW PMR-II parts equal in quality to those made by compression molding. Well suited to use at temperatures up to 700 degrees F (371 degrees C). In aircraft engines, they offer advantages of strength and light weight.

  3. Lightweight autoclavable wide-angle contact lens for vitreous surgery. (United States)

    Chalam, K V; Gupta, Shailesh K; Agarwal, Swati


    The authors describe an autoclavable, self-stabilizing, lightweight wide-angle contact lens for vitrectomy. The lens has two optical pieces with perforated plastic casing to sustain a high temperature (150 degrees C) for autoclaving. The lens has a 106 degrees static and 127 degrees dynamic field of view. The footplates and reduced weight (2.4 grams) due to the plastic casing allow self-stabilization of the lens. The open lens design.with high temperature resistant plastic prevents fogging during autoclaving and surgery. The autoclavable, self-stabilizing, lightweight wide-angle contact lens allows visualization of the peripheral retina during surgery and faster sterilization by autoclaving between surgeries without the disadvantage of lens fogging.

  4. Evaluation of dimensional stability of autoclavable elastomeric impression material. (United States)

    Surendra, G P; Anjum, Ayesha; Satish Babu, C L; Shetty, Shilpa


    Impressions are important sources of cross contamination between patients and dental laboratories. As a part of infection control impressions contaminated with variety of micro-organisms via blood and oral secretions should be cleaned and disinfected or sterilized before being handled in dental laboratory. The purpose of this study was to determine the effect of autoclaving on dimensional stability of elastomeric impression material (polyvinyl siloxane-Affinis). In this in vitro study standardized stainless steel die as per ADA specification number 19 was fabricated. Polyvinyl siloxane (Affinis) light body and putty viscosity elastomeric impression materials were used. A total of 40 impressions of the stainless steel die were made and numeric coding system was used to identify the samples. Measurements were made using a measuring microscope. Distance between the cross lines CD and C'D' reproduced in the impression were measured before autoclaving, immediately after autoclaving and 24 hours after autoclaving and dimensional change was calculated. The data obtained was subjected to statistical analysis. The mean difference in dimensional change between the three groups was not statistically significant (P > 0.05). However the results revealed that there was higher mean dimensional change immediately after autoclaving when compared to the other 2 time intervals. It is desirable to delay the casting of an autoclavable elastomeric impression material by about 24 hours. Though disinfection of impression is routinely followed autoclaving of impression is an effective method of sterilization.

  5. Autoclave decomposition method for metals in soils and sediments. (United States)

    Navarrete-López, M; Jonathan, M P; Rodríguez-Espinosa, P F; Salgado-Galeana, J A


    Leaching of partially leached metals (Fe, Mn, Cd, Co, Cu, Ni, Pb, and Zn) was done using autoclave technique which was modified based on EPA 3051A digestion technique. The autoclave method was developed as an alternative to the regular digestion procedure passed the safety norms for partial extraction of metals in polytetrafluoroethylene (PFA vessel) with a low constant temperature (119.5° ± 1.5°C) and the recovery of elements were also precise. The autoclave method was also validated using two Standard Reference Materials (SRMs: Loam Soil B and Loam Soil D) and the recoveries were equally superior to the traditionally established digestion methods. Application of the autoclave was samples from different natural environments (beach, mangrove, river, and city soil) to reproduce the recovery of elements during subsequent analysis.

  6. No-Oven, No-Autoclave, Composite Processing Project (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) proposes to continue the efforts from the 2010 NASA SBIR Phase I topic X5.03, "No-Oven, No-Autoclave (NONA) Composite...

  7. Identification of autoclave-resistant Anisakis simplex allergens. (United States)

    Carballeda-Sangiao, Noelia; Olivares, Fabiola; Rodriguez-Mahillo, Ana I; Careche, Mercedes; Tejada, Margarita; Moneo, Ignacio; González-Muñoz, Miguel


    Anisakis simplex is a fish parasite able to induce allergic reactions in humans infected when eating raw or undercooked fish parasitized with viable third-stage larvae. Some authors claim that exposure to nonviable Anisakis material can result in allergic symptoms in previously sensitized patients, indicating that parasite allergens are resistant to the thermal treatments of usual cooking procedures. Furthermore, some patients report symptoms after eating canned fish. The aim of this work was the analysis of parasite allergen stability in heating to 121 °C in an autoclave to simulate the thermal process applied to canned fish. Third-stage larvae were subjected to autoclaving for 20, 40, and 80 min, and parasite crude extracts were analyzed by electrophoresis, immunoblotting, and a flow-cytometric basophil activation test. Allergens resistant to autoclaving were separated by reversed-phase high-performance liquid chromatography and identified by ion trap mass spectrometry. Protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that autoclaving considerably reduced the number and intensity of identifiable protein bands in a time-dependent manner. Several allergens were detected by immunoblotting with a pool of A. simplex allergic patients' sera after autoclaving. Allergens of 9 and 14 kDa resistant to autoclaving were identified as Ani s 4 and Ani s 1 allergens, respectively. Functional analysis showed that allergens retain their capacity to activate basophils even after autoclaving for 80 min. In conclusion, some relevant A. simplex allergens retain their capacity to bind immunoglobulin E and activate basophils after being subjected to autoclaving, which is a method equivalent to that used in industrial canning processes.

  8. Generating Autoclave-Level Mechanical Properties with Out-of-Autoclave Thermoplastic Placement of Large Composite Aerospace Structures Project (United States)

    National Aeronautics and Space Administration — Out-of-autoclave thermoplastic tape/tow placement (TP-ATP) is nearing commercialization but suffers a moderate gap in mechanical properties compared with laminates...

  9. Hard and soft computing models of composite curing process looking toward monitoring and control (United States)

    Rubino, F.; Carlone, P.; Aleksendrić, D.; Ćirović, V.; Sorrentino, L.; Bellini, C.


    The curing process of thermosetting resins plays a key role on the final quality of the composite material components. Soft computing techniques proved to be an efficient method to control and optimize the curing process, replacing the conventional experimental and numerical approaches. In this paper artificial neural network (ANN) and fuzzy logic control (FLC) were implemented together to predict and control the temperature and degree of cure profile during the autoclave curing process. The obtained outcomes proved the capability of ANNs and FLC with respect to the hard computing methods.

  10. Evaluation of Sandwich Structure Bonding In Out-of-Autoclave Processing (United States)

    Hou, Tan-Hung; Baughman, James M.; Zimmerman, Thomas J.; Sutter, James K.; Gardner, John M.


    The out-of-autoclave-vacuum-bag-only (OOA-VBO) process is low in capital expenditures compared to the traditional autoclave, however, the material challenges for OOA-VBO workable material systems are high. Presently there are few such aerospace grade prepreg materials available commercially. In this study, we evaluated processing and properties of honeycomb sandwich structure (HC/SS) panels fabricated by co-curing composite face sheet with adhesives by the OOA-VBO process in an oven. The prepreg materials were IM7/MTM 45-1 and T40-800B/5320. Adhesives studied were AF-555M, XMTA-241/PM15, FM-309-1M and FM-300K. Aluminum H/C cores with and without perforations were included. It was found that adhesives in IM7/MTM 45-1/AF-555M, T40-800B/5320/FM 309-1M and T40-800B/5320/FM-300K panels all foamed but yielded high flatwise tensile (FWT) strength values above 8,275 kPA (1,200 psi). IM7/MTM 45-1/XMTA-241/PM15 did not foam, yet yielded a low FWT strength. SEM photomicrographs revealed that the origin of this low strength was poor adhesion in the interfaces between the adhesive and face sheet composite due to poor wetting associated with the high initial viscosity of the XMTA-241/PM15 adhesive.

  11. Numerical and Experimental Study of the Bleeder Flow in Autoclave Process (United States)

    Li, Yanxia; Li, Min; Gu, Yizhuo; Zhang, Zuoguang


    In the autoclave process, resin flow is a primary mechanics for the removing of excess resin and voids entrapped in the laminate and obtaining a uniform and void free composite part. A numerical method was developed to simulate the resin flow in the laminate and the bleeder, and the effects of `bleeder flow' on the resin flow and fiber compaction were conducted. At the same time, fiber distribution in the cured laminates was investigated by both experiments and simulations for the CF/Epoxy and CF/BMI composites. The data of the experiments and simulations demonstrated that fibers consolidated and reconsolidated in the laminate and it was impacted by the viscosity and gel time of the resin system. Compared to the post study in which only resin flow in the laminate are considered, these results will deepen the understanding of the consolidation process, resin pressure variation and void control during the autoclave process, which is valuable for the study of the performance of composite parts, provided that fiber distribution does affect some properties of composite material.

  12. Optimization of the curing process of a sandwich panel (United States)

    Phyo Maung, Pyi; Tatarnikov, O.; Malysheva, G.


    This study presented finite element modelling and experimental measurements of temperatures during the autoclave curing of the T-50 aircraft wing sandwich panel. This panel consists of upper and lower carbon fibre based laminates and an aluminium foil honeycomb. The finite element modelling was performed using the Femap-Nastran product. During processing, the temperature at various points on the surface of the panel was measured using the thermocouples. The finite element method simulated the thermal conditions and determined the temperatures in the different parts of the panel for a full cycle of the curing process. A comparison of the calculated and experimental data shows that their difference does not exceed 6%.

  13. Modelling heat generation and transfer during cure of thermoset composites processed by resin transfer moulding (RTM)


    Skordos, Alexandros A.; Maistros, George M.; Turmel, Denis J-P; Partridge, Ivana K


    The development of a heat transfer model for the curing stage of the RTM process is presented. Despite the intense interest in the modelling and simulation of this process the relevant work is currently limited to development of flow models of the filling stage. The principles of heat transfer modelling of composites cure have already been reported and applied to the autoclave process by many investigators. In the present investigation, the same concept is used for the imple...

  14. X-33 Tank Failure During Autoclave Fabrication (United States)

    Nettles, Alan T.; Munafo, Paul (Technical Monitor)


    During a repair cure cycle on tank #1 of the X-33 liquid hydrogen tanks, a skin to core disbond occurred. Both the inner skin and outer skin of the lobe #1 sandwich panel was noted to have been disbonded and cracked- An investigation was undertaken to determine the cause of this failure. The investigation consisted of reviewing all of the processing data and performing testing on the failed lobe #1, as well as the other lobes, which did not fail during the cure cycle. The tests consisted of residual stress measurements in one of the intact lobes and "plug-pulls" to assess skin to core strength on all of the remaining lobes. Results showed an extremely low bondline strength due to lack of proper filleting of the adhesive, in addition, tests showed a very rapid decrease in strength with increasing temperature, as well as a further decrease in strength with a larger number of cycles. Also, the honeycomb used was not vented so pressure could build up within the cells. All of these factors appeared to be contributors to the failure.

  15. Color stability of shade guides after autoclave sterilization. (United States)

    Schmeling, Max; Sartori, Neimar; Monteiro, Sylvio; Baratieri, Luiz


    This study evaluated the influence of 120 autoclave sterilization cycles on the color stability of two commercial shade guides (Vita Classical and Vita System 3D-Master). The specimens were evaluated by spectrophotometer before and after the sterilization cycles. The color was described using the three-dimensional CIELab system. The statistical analysis was performed in three chromaticity coordinates, before and after sterilization cycles, using the paired samples t test. All specimens became darker after autoclave sterilization cycles. However, specimens of Vita Classical became redder, while those of the Vita System 3D-Master became more yellow. Repeated cycles of autoclave sterilization caused statistically significant changes in the color coordinates of the two shade guides. However, these differences are considered clinically acceptable.

  16. Anaerobic digestion of autoclaved and untreated food waste

    Energy Technology Data Exchange (ETDEWEB)

    Tampio, Elina, E-mail: [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland); Ervasti, Satu; Paavola, Teija [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland); Heaven, Sonia; Banks, Charles [University of Southampton, Faculty of Engineering and the Environment, Southampton SO17 1BJ (United Kingdom); Rintala, Jukka [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland)


    Highlights: • Autoclaving decreased the formation of NH4-N and H{sub 2}S during food waste digestion. • Stable digestion was achieved with untreated and autoclaved FW at OLR 6 kg VS/m{sup 3}day. • Use of acclimated inoculum allowed very rapid increases in OLR. • Highest CH{sub 4} yields were observed at OLR 3 kg VS/m{sup 3}day with untreated FW. • Autoclaved FW produced highest CH{sub 4} yields during OLR 4 kgVS/m{sup 3}day. - Abstract: Anaerobic digestion of autoclaved (160 °C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids (VS)/m{sup 3} d. Methane yields at all OLR were 5–10% higher for untreated FW (maximum 0.483 ± 0.013 m{sup 3} CH{sub 4}/kg VS at 3 kg VS/m{sup 3} d) than autoclaved FW (maximum 0.439 ± 0.020 m{sup 3} CH{sub 4}/kg VS at 4 kg VS/m{sup 3} d). The residual methane potential of both digestates at all OLRs was less than 0.110 m{sup 3} CH{sub 4}/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.

  17. Improving and monitoring autoclave performance in dental practice. (United States)

    Palenik, C J; Burke, F J; Coulter, W A; Cheung, S W


    The sterilisation of instruments is central to the infection control process in the dental surgery, with the autoclave being most frequently used for this process. For effective operation, among other factors, it is essential that the autoclave is loaded correctly and tested regularly to ensure that it is operating at a temperature and pressure which will kill all micro-organisms. Biological indicators are another method of verifying the sterilisation process, since the sterilisation of the bacterial spores within the test ampoule provides a guarantee that sterilising conditions have been achieved.

  18. Effect of In-Situ Curing on Compressive Strength of Reactive Powder Concrete

    Directory of Open Access Journals (Sweden)

    Bali Ika


    Full Text Available A development of Reactive Powder Concrete (RPC currently is the use of quartz powder as a stabilizing agent with the content to cement ratio of 30% and steam curing method in an autoclave temperature of 250ºC which produced a high compressive strength of 180 MPa. That RPC can be generated due to one reason for using the technique of steam curing in an autoclave in the laboratory. This study proposes in-situ curing method in order the curing can be applied in the field and with a reasonable compressive strength results of RPC. As the benchmarks in this study are the curing methods in laboratory that are steam curing of 90°C for 8 hours (C1, and water curing for 28 days (C2. For the in-situ curing methods that are covering with tarpaulins and flowed steam of 3 hours per day for 7 days (C3, covering with wet sacks for 28 days (C4, and covering with wet sacks for 28 days for specimen with unwashed sand as fine aggregate (C5. The comparison of compressive strength of the specimens in this study showed compressive strength of RPC with in-situ steam curing (101.64 MPa close to the compressive strength of RPC with steam curing in the laboratory with 8.2% of different. While in-situ wet curing compared with the water curing in laboratory has the different of 3.4%. These results indicated that the proposed in-situ curing methods are reasonable good in term of the compressive strength that can be achieved.

  19. Autoclave Sterilization of PEDOT:PSS Electrophysiology Devices. (United States)

    Uguz, Ilke; Ganji, Mehran; Hama, Adel; Tanaka, Atsunori; Inal, Sahika; Youssef, Ahmed; Owens, Roisin M; Quilichini, Pascale P; Ghestem, Antoine; Bernard, Christophe; Dayeh, Shadi A; Malliaras, George G


    Autoclaving, the most widely available sterilization method, is applied to poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) electrophysiology devices. The process does not harm morphology or electrical properties, while it effectively kills E. coli intentionally cultured on the devices. This finding paves the way to widespread introduction of PEDOT:PSS electrophysiology devices to the clinic.

  20. Effectiveness of Bench Top Non-Vacuum Autoclaves on Dental Turbine Chamber Sterilization Effectiveness of Bench Top Non-Vacuum Autoclaves on Dental Turbine Chamber Sterilization

    Directory of Open Access Journals (Sweden)

    Taraneh Movahhed


    Full Text Available Introduction: Dental turbine chamber is a suitable reservoir for living microorganisms, so chamber sterilization is necessary for reducing cross contamination risk. On the other hand, in non-vacuum autoclaves, steam penetration into turbine chamber is doubtful, while they are still in use in dental clinics. In this study, performance of small non-vacuum autoclave in turbine chamber sterilization was evaluated. Methods: A total of 48 dental turbines were sterilized by large vacuum autoclaves. The turbin chamber cap was opened in aseptic enviroment and a strip contaminated with bacillus stearothermophilus endospores was placed into chamber and chamber cap was closed. Twelve dental turbines were loaded in each of four autoclaves (2 large pre-vacuum autoclaves, 2 bench top non-vacuum autoclaves and sterilization process preformed according to the manufacturer's instructions. After the sterilization cycle, the strips were transferred to culture medium and incubated at 56°C for 48 Hours. As control sample, a biologic indicator that had not been autoclaved was used for each group. Results: Being loaded in different autoclaves, All 48 turbines were sterilized properly and all the cultures were negative. The culture results of four control indicators which were not sterilized, were positive. Conclusion: There was no difference between performance of vacuum and non-vacuum autoclaves in dental turbine chamber sterilization. Both types performed sterilization properly.

  1. Development of a Fully Automated Guided Wave System for In-Process Cure Monitoring of CFRP Composite Laminates (United States)

    Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.; Yaun, Fuh-Gwo


    A guided wave-based in-process cure monitoring technique for carbon fiber reinforced polymer (CFRP) composites was investigated at NASA Langley Research Center. A key cure transition point (vitrification) was identified and the degree of cure was monitored using metrics such as amplitude and time of arrival (TOA) of guided waves. Using an automated system preliminarily developed in this work, high-temperature piezoelectric transducers were utilized to interrogate a twenty-four ply unidirectional composite panel fabricated from Hexcel (Registered Trademark) IM7/8552 prepreg during cure. It was shown that the amplitude of the guided wave increased sharply around vitrification and the TOA curve possessed an inverse relationship with degree of cure. The work is a first step in demonstrating the feasibility of transitioning the technique to perform in-process cure monitoring in an autoclave, defect detection during cure, and ultimately a closed-loop process control to maximize composite part quality and consistency.

  2. The use of solar energy for powering a portable autoclave. (United States)

    Dravid, M N; Chandak, A; Phute, S U; Khadse, R K; Adchitre, H R; Kulkarni, S D


    Climate change and the depletion of fossil fuels have forced the developed world to look for clean energy alternatives. Solar cooking is developing in Asian and African countries blessed with ample sun, but is still at an early stage. A portable autoclave was developed in India using this technology. The Prince-40 Concentrator provided adequate capacity to autoclave culture media and treat biomedical waste in a small laboratory set-up, and could save electricity worth Rs. 15,000 (188.10 GBP)/year or LPG worth Rs. 37,500 (470.25 GBP)/year. This technology would be of immense use in health centres in rural areas with frequent power cuts or no power supply.

  3. Porosity and Mechanical Strength of an Autoclaved Clayey Cellular Concrete

    Directory of Open Access Journals (Sweden)

    P. O. Guglielmi


    Full Text Available This paper investigates the porosity and the mechanical strength of an Autoclaved Clayey Cellular Concrete (ACCC with the binder produced with 75 wt% kaolinite clay and 25 wt% Portland cement. Aluminum powder was used as foaming agent, from 0.2 wt% to 0.8 wt%, producing specimens with different porosities. The results show that the specimens with higher content of aluminum presented pore coalescence, which can explain the lower porosity of these samples. The porosities obtained with the aluminum contents used in the study were high (approximately 80%, what accounts for the low mechanical strength of the investigated cellular concretes (maximum of 0.62 MPa. Nevertheless, comparing the results obtained in this study to the ones for low temperature clayey aerated concrete with similar compositions, it can be observed that autoclaving is effective for increasing the material mechanical strength.

  4. Hydrolysis of organic matter during autoclaving of commingled household waste. (United States)

    Papadimitriou, E K


    Commingled household waste (HW) that had a controlled composition was autoclaved at elevated pressures in the presence of saturated steam for one hour at the nominal temperature levels of 130 degrees C, 160 degrees C and 200 degrees C. The focus of this study was the impact of temperature/pressure on hydrolysis of organic matter during autoclaving and the extent of its hydrolysis. The pH decreased with autoclaving temperature with which it had a linear relationship, and ranged from 7.4 and 6 in floc, and 6.7 and 3.6 in steam condensate. Overall, organic matter solubilisation, as indicated by dissolved organic carbon, biological and chemical oxygen demands, and total dissolved solids, increased with temperature. Lignin did not appear to hydrolyse. Hemicellulose hydrolysed and degraded the most, followed by cellulose. The highest recoveries of hemicellulose and cellulose in solution were achieved at 160 degrees C, although the latter could be due to experimental error. The largest losses of hemicellulose and cellulose were recorded at 200 degrees C. The performance of the system in respect to hydrolysis was inferior compared to other hydrothermal systems, particularly those employing wet oxidation.

  5. Anaerobic digestion of autoclaved and untreated food waste. (United States)

    Tampio, Elina; Ervasti, Satu; Paavola, Teija; Heaven, Sonia; Banks, Charles; Rintala, Jukka


    Anaerobic digestion of autoclaved (160°C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids(VS)/m(3)d. Methane yields at all OLR were 5-10% higher for untreated FW (maximum 0.483±0.013 m(3) CH4/kg VS at 3 kg VS/m(3) d) than autoclaved FW (maximum 0.439±0.020 m(3) CH4/kg VS at 4 kg VS/m(3) d). The residual methane potential of both digestates at all OLRs was less than 0.110 m(3) CH4/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.

  6. Influence of post-cure treatments on hardness and marginal adaptation of composite resin inlay restorations: an in vitro study

    Directory of Open Access Journals (Sweden)

    Laiza Tatiana Poskus


    Full Text Available OBJECTIVES: The purpose of this study was to evaluate the Vickers hardness number (VHN and the in vitro marginal adaptation of inlay restorations of three hybrid composite resins (Filtek Z250, Opallis and Esthet-X subjected to two post-cure treatments. MATERIAL AND METHODS: For the microhardness test, three different groups were prepared in accordance with the post-cure treatments: control group (only light cure for 40 s, autoclave group (light cure for 40 s + autoclave for 15 min at 130ºC; and microwave group (light cure for 40 s + microwave for 3 min at 450 W. To assess the marginal adaptation, the composite resin was inserted incrementally into a mesial-occlusal-distal cavity brass mold and each increment light-cured for 40 s. A previous reading in micrometers was taken at the cervical wall, using a stereomicroscope magnifying glass equipped with a digital video camera and image-analysis software. Subsequently, the specimens were subjected to the post-cure treatments (autoclave and microwave and a reading was taken again at the cervical wall. Data were compared using ANOVA for the hardness test, split-plot ANOVA for the adaptation assessment and Tukey's test for multiple comparisons. A significance level of 5% was adopted for all analyses. RESULTS: The post-cure treatments increased the hardness of conventional composites (p<0.001 and the gap values of inlay restorations (p<0.01. Filtek Z250 showed higher hardness (p<0.001 and lower gap values than Opallis and Esthet-X (p<0.05. Gap values did not exceed 90 µm for any of the experimental conditions. CONCLUSION: The post-cure treatments increased the VHN and the gap values on the cervical floor of composite resin inlays. Moreover, Filtek Z250 showed the best results, with higher hardness and lower gap values.

  7. An autoclave treatment reduces the solubility and antigenicity of an allergenic protein found in buckwheat flour. (United States)

    Tomotake, Hiroyuki; Yamazaki, Rikio; Yamato, Masayuki


    The effects of an autoclave treatment of buckwheat flour on a 24-kDa allergenic protein were investigated by measuring reduction in solubility and antibody binding. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the intensity of the major bands, including that of the 24-kDa allergen, was reduced by the autoclave treatment. The protein solubility in buckwheat flour was variably decreased by the autoclave treatment. Enzyme-linked immunosorbent assay analysis using a monoclonal antibody specific for buckwheat 24-kDa protein showed that the reactivity of protein extracts (10 μg/ml) from buckwheat flour was lowered by the autoclave treatment. The autoclave treatment may reduce the major allergen content of buckwheat. Future studies will determine if autoclaving treatments affect the allergenicity of the 24-kDa buckwheat protein.

  8. Gravity Effects of Curing Angle on Laminated Composite Structures: A Review on Novel Study



    Composites manufactured by small and medium industries/entrepreneurs (SMI/E) are conventionally cured in the horizontal position. Hence, the confined space restricts optimum productivity. Besides, SMI/E is unable to allocate high budget for high-end technology such as autoclave and vacuum mechanical oven which limits the development of SMI/E as a result of high capital cost. Through a series of literature review, the review confirmed that there is no similar scientific study has been conducte...




    The authors study the possibility of increasing the polymer composite material strength, of reducing anisotropy of cross-breaking strength. The effect is achieved due to local inhibition of prepreg package. During the prepreg curing process by the vacuum-autoclave method, the inlay gelling action occurs later than in three-layer prepreg packets though they are located between them. The processes of increasing cross-breaking strength and of reducing the anisotropy are associated with the possi...

  10. Curing Behavior of Epoxy Asphalt

    Institute of Scientific and Technical Information of China (English)

    YU Jianying; CONG Peiliang; WU Shaopeng; CHENG Songbo


    The curing process of epoxy asphalt was analyzed by Fourier transform infrared (FT-IR)spectroscopy.Effect of curing temperature on viscosity of epoxy asphalt,and changes of mechanical properties with curing time were investigated.The evolution of concentration of epoxy band was followed as a function of the applied curing process.The experimental results indicate that the curing reaction rate of epoxy asphalt is invariable before 70 min at 120℃,and it decreases when curing time exceeds 70 min.The viscosity of epoxy asphalt increases slowly with curing time at initial curing stage.But it increases quickly after initial curing stage and the initial curing time decreases as the curing temperature increases.The tensile strength increases slowly at incipient curing stage and increases rapidly when curing time is form 20 min to 70 min.The elongation at break shows a decrease with curing time,but it exceeds 200%after cured.

  11. Sobrerresistencia en estructuras de concreto celular de autoclave


    J. L. Varela Rivera; S. A. Chan Esquivel; L. E. Fernández Baqueiro


    En este trabajo se determinan factores de sobrerresistencia globales (R) para estructuras en volado a base de muros de concreto celular de autoclave (CCA). Los factores R se obtienen como el producto de factores de sobrerresistencia independientes asociados a la cantidad de acero de refuerzo, el esfuerzo de fluencia del acero de refuerzo, la velocidad de aplicación de las cargas, los factores de carga y resistencia empleados en el diseño, el método de diseño empleado, la redundancia en las es...

  12. Fiber-Matrix Interface Studies on Electron Beam Cured Composites

    Energy Technology Data Exchange (ETDEWEB)

    Drazel, L.T.; Janke, C.J.; Yarborough, K.D.


    The recently completed Department of Energy (DOE) and industry sponsored Cooperative Research and Development Agreement (CRADA) entitled, ''Electron Beam Curing of Polymer Matrix Composites,'' determined that the interlaminar shear strength properties of the best electron beam cured IM7/epoxy composites were 19-28% lower than autoclave cured IM7/epoxy composites (i.e. IM7/977-2 and IM7/977-3). Low interlaminar shear strength is widely acknowledged as the key barrier to the successful acceptance and implementation of electron beam cured composites in the aircraft/aerospace industry. The objective of this work was to improve the interlaminar shear strength properties of electron beam cured composites by formulating and evaluating several different fiber sizings or coating materials. The researchers have recently achieved some promising results by having discovered that the application of epoxy-based, electron beam compatible sizings or coatings onto surface-treated, unsized IM7 carbon fibers improved the composite interlaminar shear strength properties by as much as 55% versus composites fabricated from surface-treated, unsized IM7 fibers. In addition, by applying these same epoxy-based sizings or coatings onto surface-treated, unsized IM7 fibers it was possible to achieve an 11% increase in the composite interlaminar shear strength compared to composites made from surface-treated, GP-sized IM7 fibers. Work is continuing in this area of research to further improve these properties.

  13. Carbon Foam Self-Heated Tooling for Out-of-Autoclave Composites Manufacturing Project (United States)

    National Aeronautics and Space Administration — Touchstone Research Laboratory, Ltd. (Touchstone) has developed a novel and innovative Out-of-Autoclave (OOA) composites manufacturing process with an electrically...

  14. Acidic ammonothermal growth of gallium nitride in a liner-free molybdenum alloy autoclave (United States)

    Malkowski, Thomas F.; Pimputkar, Siddha; Speck, James S.; DenBaars, Steven P.; Nakamura, Shuji


    This paper discusses promising materials for use as internal, non-load bearing components as well as molybdenum-based alloys for autoclave structural components for an ammonothermal autoclave. An autoclave was constructed from the commercial titanium-zirconium-molybdenum (TZM) alloy and was found to be chemically inert and mechanically stable under acidic ammonothermal conditions. Preliminary seeded growth of GaN was demonstrated with negligible incorporation of transition metals (including molybdenum) into the grown material (560 °C). The possibility of a 'universal', inexpensive, liner-free ammonothermal autoclave capable of exposure to basic and acidic chemistry is demonstrated.

  15. Radiation curing of epoxies (United States)

    Dickson, Lawrence W.; Singh, Ajit

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

  16. Method of controlling a resin curing process. [for fiber reinforced composites (United States)

    Webster, Charles Neal (Inventor); Scott, Robert O. (Inventor)


    The invention relates to an analytical technique for controlling the curing process of fiber-reinforced composite materials that are formed using thermosetting resins. The technique is the percent gel method and involves development of a time-to-gel equation as a function of temperature. From this equation a rate-of-gel equation is then determined, and a percent gel is calculated which is the product of rate-of-gel times time. Percent gel accounting is used to control the proper pressure application point in an autoclave cure process to achieve desired properties in a production composite part.

  17. Optimization of the Temperature-Time Curve for the Curing Process of Thermoset Matrix Composites (United States)

    Aleksendrić, Dragan; Carlone, Pierpaolo; Ćirović, Velimir


    An intelligent optimization model aiming at off-line or pre-series optimization of the thermal curing cycle of polymer matrix composites is proposed and discussed. The computational procedure is based on the coupling of a finite element thermochemical process model, dynamic artificial neural networks and genetic algorithms. Objective of the optimization routine is the maximization of the composite degree of cure by the definition of the autoclave temperature. Obtained outcomes evidenced the capability of the method as well as its efficiency with respect to hard computing or experimental procedures.

  18. Constructing of cure monitoring system with piezoelectric ceramics for composite laminate (United States)

    Oshima, Nobuo; Inoue, Kouichi; Motogi, Shinya; Fukuda, Takehito


    The cure monitoring system with piezoelectric ceramics is constructed. An embedded type piezoelectric ceramics sensor with flat lead wires is developed. And the piezoelectric ceramics is embedded into composite laminate. A dummy piezoelectric ceramics is set in the autoclave oven. The impedance of the piezoelectric ceramics which is embedded in the composite laminate and that of the dummy piezoelectric ceramics are measured by a LCR meter. The piezoelectric ceramics have strong temperature dependency. The temperature dependency of the impedance of piezoelectric ceramics is corrected by the information from the dummy piezoelectric ceramics. A dielectric sensor is also embedded in the composite laminate as a reference sensor for the degree of cure. The change in calculated cure index shows good correspondence with change in the log ion viscosity which is measured by the dielectric cure monitoring sensor.

  19. The Curing Meter

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede


    Curing technology concerns adjustment and control of temperature and moisture conditions in hardening structures and elements of concrete. The curing technology comprises e.g. measurement, adjustment and control of the moisture conditions during the early hardening phase of the concrete to achiev...... from concrete surfaces in the early hardening phase. The Concrete Curing Meter is designed for simple and reliable monitoring of water loss from a wet surface of fresh concrete. This new measuring technique has been tested with several prototypes of the Curing Meter.......Curing technology concerns adjustment and control of temperature and moisture conditions in hardening structures and elements of concrete. The curing technology comprises e.g. measurement, adjustment and control of the moisture conditions during the early hardening phase of the concrete to achieve...... an optimal development of properties in the hardening concrete – so-called "moisture curing". Proper moisture curing is vital to concrete but laborious to accomplish and difficult to control at the construction site with present methods. This paper concerns a new method for site measurement of evaporation...

  20. 煅烧磷石膏对蒸压硅酸盐制品水化过程的影响%Effect of calcined phosphogypsum on hydration process of autoclaved silicate products

    Institute of Scientific and Technical Information of China (English)

    陆金驰; 李东南; 陈凯; 黄金林


    磷石膏经高温煅烧改性后与粉煤灰、砂粉、石灰及水泥熟料等制备蒸压硅酸盐制品,研究了不同温度煅烧的磷石膏对蒸压硅酸盐制品水化过程的影响,用蒸压制品中未反应的Ca(OH)2量及结合水量分析它们的反应速率,用XRD测定蒸压硅酸盐制品的水化产物,并结合SEM分析,结果表明,经煅烧的磷石膏对蒸压硅酸盐制品的水化有明显的促进作用,托勃莫来石与C-S-H (1)等水化产物的迅速生长而形成密实的水化产物结构是其增强蒸压硅酸盐制品的根本原因.%The effects of calcined phosphogypsum on the hydration process of the autoclaved silicate products were investigated in this paper. The influence of adding phosphogypsum calcined at different temperatures on the hydration rate of autoclaved silicate products was analyzed for un-reacted Ca(OH)2 content and combined water. The hydrates were determined with XRD and SEM. It was found that the hydration of autoclaved silicate products with added phosphogypsum calcined over 500℃ was greatly improved. The hydrates of the autoclaved silicate products with added phosphogypsum calcined over 500℃ had more un-reacted Ca(OH)2 content and combined water in the same curing time, and the research indicated that adding phosphogypsum calcined over 500℃ could also reinforce the compressive strength of autoclaved silicate products. It was pointed out that the aluminate phase present in the raw materials cannot hydrate to form more ettringite during autoclaved curing, and rapid formation of such hydrates as calcium silicate hydrate (1) and tobermorite with a more compact structure is the main reason for strengthening autoclaved silicate products.

  1. Economic method of development of canned food sterilization regimes for industry autoclaves

    Directory of Open Access Journals (Sweden)

    Stolyanov A. V.


    Full Text Available Utilization of the sterilization equipment AVK-30M for development of sterilization regimes of canned food for industrial autoclaves, particularly for ASCAMAT 230, has been described. Energy consumption of autoclaves during stages of heating and sterilization has been compared as well

  2. PATI RESISTEN SAGU HASIL PROSES HIDROLISIS ASAM DAN AUTOCLAVING-COOLING [Resistant Starch of Sago from Acid Hydrolyzis and Autoclaving-Cooling Processes

    Directory of Open Access Journals (Sweden)

    Feri Kusnandar


    Full Text Available The aim of this study was to produce resistant starch (RS from a combination of acid hydrolysis and autoclaving-cooling processes of sago starch. This study compared two methods of starch modification to produce RS, i.e. (1 acid hydrolysis treatment followed by autoclaving-cooling cycles (AH-AC, and (2 autoclaving-cooling cycles followed by acid hydrolysis treatment (AC-AH. The acid hydrolysis used 1 and 2% HCl while autoclaving-cooling process consisted of three-cycle of autoclaving at 121°C for 30 min followed by cooling at 4°C for 72 hrs. Both AH-AC and AC-AH modification methods decreased starch content, altered amylose and amylopectin ratio, and increased RS contents. Both modification methods also yielded nearly flat pasting profiles at both heating and cooling phases as compared to that of native sago starch. At the same HCl concentration, the AH-AC process yielded a higher RS content than that of AC-AH. Among all treatments, the acid hydrolysis treatment using 1% HCl followed by three cycles of autoclaving-cooling process yielded the highest RS content (74.28%. The crystallinity of RS was also lower than of native sago starch, but its A crystalline type remained the same.

  3. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, D., E-mail: [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, Area delle Scienze 181/A, 43124 Parma (Italy); Michelini, E. [Department of Civil, Environmental, Land Management Engineering and Architecture, University of Parma, Area delle Scienze 181/A, 43124 Parma (Italy); Rosati, G. [Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)


    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  4. C-CURE (United States)

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

  5. Wet autoclave pretreatment for immunohistochemical demonstration of oestrogen receptors in routinely processed breast carcinoma tissue. (United States)

    Bier, B; Bankfalvi, A; Grote, L; Blasius, S; Ofner, D; Böcker, W; Jasani, B; Schmid, K W


    The immunohistochemical demonstration of oestrogen receptor (OR) was performed on 32 randomly selected and routinely processed breast carcinomas after wet autoclave pretreatment of sections. The autoclave method was compared to the OR status found on frozen sections as well as to alternative pretreatment methods such as enzymatic predigestion and microwave irradiation. Using four different monoclonal antibody clones (H222, LH1, CC4-5, 1D5.26), the OR status was evaluated for each of the various pretreatment methods applied. All cases with a high OR content on frozen sections (n = 11) also showed a high OR status on wet autoclave-pretreated paraffin tissues using antibody clones 1D5.26 and CC4-5; in cases with low OR content on frozen sections, no false-negative cases were recorded using only the antibody 1D5.26 neither after wet autoclave nor microwave pretreatment. In addition, with this antibody, OR was detectable after autoclave pretreatment in two cases which were considered to be OR-negative even on frozen sections. When the primary antibody was omitted, no false-positive cases were observed after wet autoclave pretreatment. Thus, in our hands, wet autoclave pretreatment, in combination with the antibody 1D5.26, offers a highly sensitive method for the immunohistochemical demonstration of OR in routinely formalin-fixed, paraffin-embedded sections of breast carcinomas.

  6. Effect of curing way on mechanical properties of PHC pipe piles%养护方式对PHC管桩力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    王成启; 王春明; 周郁兵; 张宜兵


    The compressive strength and brittleness and modulus of elasticity of PHC pipe piles on standard curing and non-steam autoclaved and steam autoclaved are experimentally studied. The results show that the increase value of the compressive strength decreases continually according to the sequence of standard curing and non-steam autoclaved and steam autoclaved and circumstance humidity affects brittleness of PHC pipe piles and the brittleness of non-steam autoclaved concrete is less than steam autoclaved concrete’s. Moreover, circumstance humidity affects also modulus of elasticity of PHC pipe piles, cur-ing can increases modulus of elasticity of non-steam autoclaved piles concrete and modulus of elasticity of non-steam auto-claved piles concrete greater than steam autoclaved piles concrete’s.%文章开展标准养护、免压蒸养护和高压蒸汽养护3种养护方式对PHC管桩混凝土抗压强度、脆性和弹性模量的影响研究。结果表明,3种养护方式PHC管桩混凝土的抗压强度增幅按标准养护、免压蒸养护和高压蒸养的次序递减;环境湿度对免压蒸PHC管桩混凝土的脆性有一定的影响,免压蒸混凝土的脆性小于高压蒸养混凝土;环境湿度也对免压蒸PHC管桩混凝土的弹性模量产生一定的影响,适当后期养护可提高免压蒸混凝土的弹性模量,免压蒸养护混凝土的弹性模量大于高压蒸养混凝土。



    Ладієва, Леся Ростиславівна; Ширма, А. В.


    The algorithm of optimal control of autoclave start mode in the production of nitric acid is proposed. By optimality criterion is selected minimum time-autoclave at preset mode with the restriction on the concentration of nitric acid. End time start mode is entered on the terminal part of the cost function. The method of penalties and a gradient procedure is used to solve the problem. The applied algorithm is allowed to bring an autoclave at a given technological regime.Keywords: production o...

  8. Radiation curing in the eighties

    Energy Technology Data Exchange (ETDEWEB)

    Vrancken, A. (UCB, Drogenbos (Belgium). Chemical Specialities Div.)


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

  9. Characteristics of an Extrusion Panel Made by Applying a Modified Curing Method

    Directory of Open Access Journals (Sweden)

    Haseog Kim


    Full Text Available CO2 emitted from building materials and the construction materials industry has reached about 67 million tons. Controls on the use of consumed fossil fuels and the reduction of emission gases are essential for the reduction of CO2 in the construction area as one reduces the second and third curing to emit CO2 in the construction materials industry. In this study, a new curing method was addressed by using a low energy curing admixture (LA in order to exclude autoclave curing. The new curing method was applied to make panels. Then, its physical properties, depending on the mixed amount of fiber, type of fiber and mixed ratio of fiber, were observed. The type of fiber did not appear to be a main factor that affected strength, while the LA mixing ratio and mixing amount of fiber appeared to be major factors affecting the strength. Applying the proposed new curing method can reduce carbon and restrain the use of fossil fuels through a reduction of the second and third curing processes, which emit CO2 in the construction materials industry. Therefore, it will be helpful to reduce global warming.

  10. Gravity Effects of Curing Angle on Laminated Composite Structures: A Review on Novel Study

    Directory of Open Access Journals (Sweden)

    T. T. T. Jennise


    Full Text Available Composites manufactured by small and medium industries/entrepreneurs (SMI/E are conventionally cured in the horizontal position. Hence, the confined space restricts optimum productivity. Besides, SMI/E is unable to allocate high budget for high-end technology such as autoclave and vacuum mechanical oven which limits the development of SMI/E as a result of high capital cost. Through a series of literature review, the review confirmed that there is no similar scientific study has been conducted. Consequently, the review is carried out to facilitate the investigation of the feasibility of a gravity cured glass fiber laminated thermosetting composites via vacuum bagging at angle position from horizontal (0° to vertical (90° to enhance the curing space required.

  11. Thermal Insulation and Strength of Autoclaved Light Concrete

    Institute of Scientific and Technical Information of China (English)

    YANG Ruochong; ZHU Jipeng; WU Zhishen; WU Zhiren; LI Min; PENG Changhai


    The primary objective of this study was to develop an autoclaved light concrete (ALC) material with ultra-thermal insulation property and to investigate the relationship between its physical characteristics and mechanical properties. Through tests of dry bulk density and compressive strength, relationship of physical characteristics and mechanical properties of samples were studied,resulting in a material with ultra-thermal insulation property. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) were applied to analyze the micro-morphology and elemental composition of samples. To identify the product phases, X-ray diffraction (XRD) was engaged. The test results showed that compressive strength and thermal coefficient were reduced with the increasing of aluminum powder within the mixtures. As a result the optimal thermal coefficient and compressive strength of samples were improved to 0.061 W/(m · k) and 1.2 MPa, respectively. SEM,EDX and XRD analyses showed that calcium silicate hydrate and tobermorite crystal were main resultant phases.

  12. Carbon Foam Self-Heated Tooling for Out-of-Autoclave Composites Manufacturing Project (United States)

    National Aeronautics and Space Administration — This proposal addresses NASA's need for non-autoclave composites manufacture. The Constellation program, including the Ares V launch vehicle, will require very...

  13. Leaching of a copper flotation concentrate with ammonium persulfate in an autoclave system

    Institute of Scientific and Technical Information of China (English)

    M Deniz Turan; H Soner Altundoan


    The leaching behavior of a copper flotation concentrate was investigated using ammonium persulfate (APS) in an autoclave sys-tem. The decomposition products of APS, active oxygen, and acidic medium were used to extract metals from the concentrate. Leaching ex-periments were performed to compare the availability of APS as an oxidizing agent for leaching of the concentrate under atmospheric condi-tions and in an autoclave system. Leaching temperature and APS concentration were found to be important parameters in both leaching sys-tems. Atmospheric leaching studies showed that the metal extractions increased with the increase in APS concentration and temperature (up to 333 K). A similar tendency was determined in the autoclave studies up to 423 K. It was also determined that the metal extractions de-creased at temperatures above 423 K due to the passivation of the particle surface by molten elemental sulfur. The results showed that higher copper extractions could be achieved using an autoclave system.

  14. In vitro comparison of autoclave polymerization on the transverse strength of denture base resins. (United States)

    Durkan, Rukiye; Ozel, Mehmet Birol; Bağiş, Bora; Usanmaz, Ali


    The aim of this study was to determine the effect of autoclave polymerization on the transverse strength of denture base polymers. To this end, 30 rectangular test specimens were fabricated of two heat-polymerized denture base polymers. The test groups were: (I) control, i.e., conventional water bath to polymerize resins by heat at 100 degrees C for 30 minutes; (II) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 10 minutes; and (III) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 20 minutes. The specimens were tested with three-point bending test at a crosshead speed of 5 mm/min. It was revealed that the transverse strength of specimens increased with statistical significance when the autoclave was used for polymerization.

  15. Dual cure photocatalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    DeVoe, R.J.; Brown-Wensley, K.A.; Holmes, G.L.; Mathis, M.D.; McCormick, F.B.; Palazzotto, M.C.; Spurgeon, K.M. (Minnesota Mining and Mfg. Co., St. Paul, MN (USA). Corporate Research Labs.)


    A family of dual cure photocatalyst systems is being developed to be used in the solventless processing of organic coatings. The photocatalyst systems consist of organometallic compounds often in combination with other agents. Upon photolysis, the photocatalyst system generates a Lewis acid and a free radical. The Lewis acid can initiate the polymerization of epoxies or the addition of isocyanates and polyols to form polyurethanes while the free radical can initiate the polymerization of acrylates. The performance of the various photocatalyst systems will be compared on the basis of the physical properties of the cured compositions they produce. 17 figs.

  16. The Effect of Autoclaving on Torsional Moment of Two Nickel-Titanium Endodontic Files (United States)


    Endodontic Journal , doi:10.1111/j.1365- 2591.2011.01958.x 45, 156–161, 2012 doi:10.1111/j.1365-2591.2011.01958.x Wiley Blackwell Publishing, 111 River... Journal , 45, 156–161, 2012. 15. SUBJECT TERMS autoclave, nickel–titanium, rotary endodontic , torsion. 16. SECURITY CLASSIFICATION OF: unclassified 17... endodontic files. International Endodontic Journal , 45, 156–161, 2012. Aim To evaluate the effects of repeated autoclaving on torsional strength of two

  17. Radiography Monitoring of Osteoconduction and Osteoinduction of Orthotopic Allograft Autoclaved Covered With Propolis


    BOUDRA Abdellatif; Hamdi, Mohamed; AMARA Karim; BOUKNINE Asma


    The veterinarian orthopedic surgeon is often faced to the loss of bone substance in diaphyseal region of long bones. Our study is based on a biological approach to the filling of segmental bone loss by implanting an autoclaved orthotopic allograft of one centimeter length covered and uncovered with propolis in the femoral diaphysis under general anesthesia and sterile condition. The experiment involved eight adult dogs, from local breed and different sex; split into two groups. An autoclaved ...

  18. Low-coherence interferometric measurements of optical losses in autoclave cured composite samples with embedded optical fibers (United States)

    Di Sante, Raffaella; Bastianini, Filippo; Donati, Lorenzo


    In this work a high-performance optical low-coherence reflectometer (OLCR) has been used to estimate the optical losses in optical fibers and fiber Bragg grating sensors embedded into CFRP material samples. An ASE tunable narrowband light source coupled to a Michelson interferometer allowed the high spatial resolution localization of both the concentrated and the distributed loss for different fiber coatings and type. In particular, acrylate- and polyimidecoated fibers and bend-insensitive fibers were tested. By using the OLCR it was possible to locate and identify the sources of optical loss introduced by the CFRP manufacturing process, therefore obtaining useful information on the efficiency of the embedding process.

  19. Morphological effects of autoclaved diet on the myenteric neurons of rats

    Institute of Scientific and Technical Information of China (English)

    Patrícia O Gon(c)alez; Naianne K Clebis; Renata B Mari; Karina M Gagliardo; Sandra R Stabille; Haroldo G Faria; Edson A Liberti; José Roberto Kfoury Jr


    AIM: To evaluate the effect of autoclaved diet on the jejunum neurons of the myenteric plexus of rats during their growth.METHODS: The experimental groups were made up of rats going through weaning whose mothers Received either an autoclaved or a non-autoclaved diet during gestation and lactation, and rats that were fed the same diet as their mothers during the post-weaning period. In order to measure the neurons' body pro-file and to quantify the number of neurons per area, preparations were stained by the nicotinamide adenine dinucleotide-diaphorase method.RESULTS: No significant changes were observed in rats' body weight or in the number of neurons regard-less of the diet used (P > 0.05). There was a decrease in the jejunum-ileum length in rats treated with an autoclaved diet (P < 0.05). An increase in the neuronal cross-sectional area was seen in rats that had Received the autoclaved diet, an effect that was significant for animals undergoing weaning. In addition, all observed factors showed significant differences when related to the age of the animals.CONCLUSION: The autoclaved diet did not alter the quantity of neurons, but increased their cell body area, suggesting changes similar to those observed in pro-tein deficiency.

  20. Effect of Sterilization by Dry Heat or Autoclaving on Bacterial Penetration through Berea Sandstone. (United States)

    Jenneman, G E; McInerney, M J; Crocker, M E; Knapp, R M


    A study was undertaken to determine why bacteria could penetrate lengths of consolidated sandstone (Berea) faster when the sandstone was sterilized by autoclaving than when dry heat (150 degrees C, 3 h) was used. Changes in permeability, porosity, and pore entrance size of the rock as a result of autoclaving were not sufficient to explain the differences in penetration times observed, but electron dispersion spectroscopy and electron microscopy of the rock revealed changes in mineral composition and clay morphology. Autoclaved cores contained more chloride than dry-heated cores, and the clays of autoclaved cores were aggregated and irregularly shaped. Therefore, the decreases in bacterial penetration rates caused by autoclave sterilization were probably the result of a change in surface charge of the pores of the rock and of a reduction in surface area of clays available for adhesion. The results implied that dry-heat sterilization was preferable to autoclaving when examining biotic and abiotic interactions in a native-state rock model.

  1. Evaluation of dimensional stability and accuracy of autoclavable polyvinyl siloxane impression material. (United States)

    Reddy, Subash M; Vijitha, D; Karthikeyan, S; Balasubramanian, R; Satish, A


    Dimensionally stable autoclavable impressions will be effective in controlling the cross-infection and contamination caused by patient's saliva and other oral secretions. The accuracy of newly introduced autoclavable polyvinyl siloxane impression material was assessed for its dimensional stability and accuracy. A standard metal model (Dentoform, U-501, Columbia) was customised for impression making. The impressions were made using the newly introduced polyvinyl siloxane impression materials (AFFINIS, Coltene/Whaledent AG, 9450 Alstalten, Switzerland). Fifty impressions were made and were divided into two groups A and B of 25 each. Group A was the control sample (non-autoclaved impressions) and group B was the test sample (autoclaved impressions), which was subjected to the steam autoclave procedure at 134 °C for 18 min, casts were poured in type IV gypsum products. The customised metal model, casts obtained from control and test group were subjected to laboratory evaluation with help of a travelling microscope (×10 magnification), and digital vernier calliper (0.01 mm/10 μm accuracy). Data analysis was done using one-way ANOVA and One-Sample t test to evaluate the overall accuracy (P polyvinyl siloxane impression material is accurate and dimensional stable for clinical use when steam autoclaved at 134 °C for 18 min.

  2. Curing the queue

    NARCIS (Netherlands)

    Zonderland, Maartje Elisabeth


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


    Directory of Open Access Journals (Sweden)

    Mr. Alexander E. Protsenko


    Full Text Available The authors study the possibility of increasing the polymer composite material strength, of reducing anisotropy of cross-breaking strength. The effect is achieved due to local inhibition of prepreg package. During the prepreg curing process by the vacuum-autoclave method, the inlay gelling action occurs later than in three-layer prepreg packets though they are located between them. The processes of increasing cross-breaking strength and of reducing the anisotropy are associated with the possibility of free shrinkage of three-layer prepreg packets.

  4. Efficient composite fabrication using electron-beam rapidly cured polymers engineered for several manufacturing processes

    Energy Technology Data Exchange (ETDEWEB)

    Walton, T.C. [Aeroplas Corp. International, Nashua, NH (United States); Crivello, J.V. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Chemistry


    Low cost, efficiently processed ultra high specific strength and stiffness graphite fiber reinforced polymeric composite materials are of great interest to commercial transportation, construction and aerospace industries for use in various components with enhanced degrees of weight reduction, corrosion/erosion resistance and fatigue resistance. 10 MeV Electron Beam cure processing has been found to increase the cure rate by an order of magnitude over thermally cured systems yet provide less molded in stresses and high T{sub g}s. However, a limited range of resins are available which are easily processed with low shrinkage and with performance properties equal or exceeding those of state of the art toughened epoxies and BMI`s. The technology, introduced by an academia-industry partnership sparked by Langley Research Center utilizes a cost effective, rapid curing polymeric composite processing technique which effectively reduces the need for expensive tooling and energy inefficient autoclave processing and can cure the laminate in seconds (compared to hours for thermal curing) in ambient or sub-ambient conditions. The process is based on electron beam (E-Beam) curing of a new series of (65 to 1,000,000 cPs.) specially formulated resins that have been shown to exhibit excellent mechanical and physical properties once cured. Fabrication processes utilizing these specially formulated and newly commercialized resins, (e.g. including Vacuum Assist Resin Transfer molding (VARTM), vacuum bag prepreg layup, pultrusion and filament winding grades) are engineered to cure with low shrinkage, provide excellent mechanical properties, be processed solventless (environmentally friendly) and are inherently non toxic.

  5. Composite Cure Process Modeling and Simulations using COMPRO(Registered Trademark) and Validation of Residual Strains using Fiber Optics Sensors (United States)

    Sreekantamurthy, Thammaiah; Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.


    Composite cure process induced residual strains and warping deformations in composite components present significant challenges in the manufacturing of advanced composite structure. As a part of the Manufacturing Process and Simulation initiative of the NASA Advanced Composite Project (ACP), research is being conducted on the composite cure process by developing an understanding of the fundamental mechanisms by which the process induced factors influence the residual responses. In this regard, analytical studies have been conducted on the cure process modeling of composite structural parts with varied physical, thermal, and resin flow process characteristics. The cure process simulation results were analyzed to interpret the cure response predictions based on the underlying physics incorporated into the modeling tool. In the cure-kinetic analysis, the model predictions on the degree of cure, resin viscosity and modulus were interpreted with reference to the temperature distribution in the composite panel part and tool setup during autoclave or hot-press curing cycles. In the fiber-bed compaction simulation, the pore pressure and resin flow velocity in the porous media models, and the compaction strain responses under applied pressure were studied to interpret the fiber volume fraction distribution predictions. In the structural simulation, the effect of temperature on the resin and ply modulus, and thermal coefficient changes during curing on predicted mechanical strains and chemical cure shrinkage strains were studied to understand the residual strains and stress response predictions. In addition to computational analysis, experimental studies were conducted to measure strains during the curing of laminated panels by means of optical fiber Bragg grating sensors (FBGs) embedded in the resin impregnated panels. The residual strain measurements from laboratory tests were then compared with the analytical model predictions. The paper describes the cure process

  6. Morpho-structural variations of bacterial spores after treatment in steam vacuum assisted autoclave. (United States)

    Fonzi, M; Montomoli, E; Gasparini, R; Devanna, D; Fonzi, L


    This study intended to verify, through microbiological techniques and TEM investigations, the killing of bacterial spores after treatment in steam autoclave, and to propose strictly morphological considerations about the target of this sterilisation process. Autoclave is the most common device for sterilising instruments in order to prevent cross infections in dental offices. The autoclave efficiency has been improved in the last years and part of this improvement is related to both a better and more correct use of the autoclave system and to the technological innovations introduced in the last generation of devices. However, associations as ADA or CDC suggest to regularly verify the process of 'autoclaving' through biological indicators (BI). The most commonly used BI are made of spores strips or suspensions of Bacillus Subtilis (pb 168) and Bacillus Stearothermophilus (ATCC 10149). They visually prove, changing colours on enzymatic base, the death of micro-organism and if the physical parameters, necessary for sterilisation, have been achieved. These two strains of endospore-forming bacteria were processed and prepared following two different techniques: Karnovsky fixed and epon embedded--phosphotungstic acid fixed for direct observation. The kind and the extent of analysed modifications are extremely various: from deep lacerations, which changed the spore structure, to little clefts which let the cytoplasm go out.

  7. Some factors affecting the compressive strength of nickel slag autoclaved product%影响镍渣蒸压制品抗压强度的因素研究

    Institute of Scientific and Technical Information of China (English)

    余涛; 曹德光; 刘文威; 李浩璇; 陆石强


    试验利用镍渣、水泥熟料、熟石灰、电石渣等原料制备镍渣蒸压制品,探索了成型压力、增强剂加入量、加水量和蒸养制度等因素对镍渣蒸压制品抗压强度的影响规律.结果表明,本试验合适的成型压力为15~20 MPa,增强剂的最佳加入量为0.5%,合理的加水量为8.57%~10.00%,最佳的蒸压养护温度为180℃或190℃,对应的蒸压养护时间为8h或9h.此外,使用电石渣代替熟石灰利用相同工艺条件制备蒸压制品的抗压强度无明显差异.%Prepared from autoclaved product of nickel slag,cement clinker,slaked lime,carbide slag,the experiment studied some factors that affecting the compressive strength of nickel slag autoclaved product,such as molding pressure,content of enhancer,content of water added,steam curing system and so on.The results show that the suitable molding pressure is 15~20 MPa;the optimum enhancer content is 0.5%;the reasonable amount of water added is 8.57%~10.00%;the best autoclaving temperature is 180 ℃ or 190 ℃;autoclaving time is eight or nine hours.In addition,under the same process conditions,autoclaved product was successfully prepared if using carbide slag instead of slaked lime,and the compressive strength of autoclaved product had no significant difference.

  8. Modeling and simulation of high-pressure industrial autoclave polyethylene reactor

    Directory of Open Access Journals (Sweden)


    Full Text Available High-pressure technology for polyethylene production has been widely used by industries around the world. A good model for the reactor fluid dynamics is essential to set the operating conditions of an autoclave reactor. The high-pressure autoclave reactor model developed in this work was based on a non-isothermal dynamic model, where PID control equations are used to maintain the operation at the unstable steady state. The kinetic mechanism to describe the polymerization rate and molecular weight averages are presented. The model is capable of computing temperature, concentration gradients and polymer characteristics. The model was validated for an existing industrial reactor and data for production of homopolymer polyethylene and has represented well the behavior of the autoclave reactor used in ethylene homopolymerization.



    R BELOUETTAR; Klepaczko, J.R.; Abadlia, M.T.


    Ce travail présente une étude expérimentale du comportement mécanique du béton cellulaire autoclavé. L’étude est portée essentiellement sur une série d’essais mécaniques en compression quasistatique à différentes vitesses de déformation variables entre 10-4 s-1 et 10 s-1 et à deux états différents (état sec et état saturé d’eau). En général, l’augmentation de la vitesse de déformation donne une augmentation de la contrainte critique du béton cellulaire autoclavé. Le béton cellulaire autoclavé...

  10. One-step formation and sterilization of gellan and hyaluronan nanohydrogels using autoclave. (United States)

    Montanari, Elita; De Rugeriis, Maria Cristina; Di Meo, Chiara; Censi, Roberta; Coviello, Tommasina; Alhaique, Franco; Matricardi, Pietro


    The sterilization of nanoparticles for biomedical applications is one of the challenges that must be faced in the development of nanoparticulate systems. Usually, autoclave sterilization cannot be applied because of stability concerns when polymeric nanoparticles are involved. This paper describes an innovative method which allows to obtain, using a single step autoclave procedure, the preparation and, at the same time, the sterilization of self-assembling nanohydrogels (NHs) obtained with cholesterol-derivatized gellan and hyaluronic acid. Moreover, by using this approach, NHs, while formed in the autoclave, can be easily loaded with drugs. The obtained NHs dispersion can be lyophilized in the presence of a cryoprotectant, leading to the original NHs after re-dispersion in water.

  11. Improved extraction procedures for polychlorinated biphenyls in solid samples with aqueous sodium hydroxide under autoclave conditions. (United States)

    Akimoto, Y; Inouye, Y


    The efficacy of the extraction of polychlorinated biphenyls (PCBs) from varnish-infiltrated insulating papers as a model of solid materials with an aqueous sodium hydroxide (NaOH) by autoclaving at 121 degrees C for 30 min was compared with those for the conventional procedures, i.e., saponification with 1 N ethanolic NaOH in a boiling water bath for 60 min and extraction with benzene in a Soxhlet apparatus. The newly invented autoclaving method was found to be superior to the conventional ones, yielding approximately 5- to 6-fold cumulative PCB congeners without being accompanied by extended decomposition. Therefore, the autoclave-based sample treatment is recommended for more accurate determination of PCBs in the case of PCB-impregnated solid materials such as hardened oils and resin-coated or -infiltrated papers instead of being treated conventionally.

  12. Control over particle size distribution by autoclaving poloxamer-stabilized trimyristin nanodispersions

    DEFF Research Database (Denmark)

    Göke, Katrin; Roese, Elin; Arnold, Andreas


    into the bloodstream. Consequently, small particles with a narrow particle size distribution are desired. Hitherto, there are, however, only limited possibilities for the preparation of monodisperse, pharmaceutically relevant dispersions. In this work, the effect of autoclaving at 121 °C on the particle size...... distribution of lipid nanoemulsions and -suspensions consisting of the pharmaceutically relevant components trimyristin and poloxamer 188 was studied. Additionally, the amount of emulsifier needed to stabilize both untreated and autoclaved particles was assessed. In our study, four dispersions of mean particle...... sizes from 45 to 150 nm were prepared by high-pressure melt homogenization. The particle size distribution before and after autoclaving was characterized using static and dynamic light scattering, differential scanning calorimetry, and transmission electron microscopy. Asymmetrical flow field...

  13. The release of 14C—chlorsulfuron bound residue by autoclaving method and its identification

    Institute of Scientific and Technical Information of China (English)

    GUOJiangfeng; PINGXiaofei; 等


    When individual microorganisms were used to release bound pesticide resdues,it was ussually not take into full account whether the autoclaving method could lead to the release of bound residues.The soil containing bound 14C-chlorsulfuron residues was treated with an autoclave in this study.The results reveal that the bound 14C-chlorsulfuron residue can be released from the soil when treated with the autoclave and the release rate can be remarkably enhanced by adding water into the soil when subjected to such treatment.A TLC analysis showed that the released 14C-residue was one of the degraded products of 14C-chlorsulfuron.After derivatization and analysis using the GC-MS,the released 14C-residue was tentatively identified as 2-amnino-4-hydroxyl-6-methyl-1,3,5-triazine.

  14. UV irradiation and autoclave treatment for elimination of contaminating DNA from laboratory consumables. (United States)

    Gefrides, Lisa A; Powell, Mark C; Donley, Michael A; Kahn, Roger


    Laboratories employ various approaches to ensure that their consumables are free of DNA contamination. They may purchase pre-treated consumables, perform quality control checks prior to casework, and use in-house profile databases for contamination detection. It is better to prevent contamination prior to DNA typing than identify it after samples are processed. To this end, laboratories may UV irradiate or autoclave consumables prior to use but treatment procedures are typically based on killing microorganisms and not on the elimination of DNA. We report a systematic study of UV and autoclave treatments on the persistence of DNA from saliva. This study was undertaken to determine the best decontamination strategy for the removal of DNA from laboratory consumables. We have identified autoclave and UV irradiation procedures that can eliminate nanogram quantities of contaminating DNA contained within cellular material. Autoclaving is more effective than UV irradiation because it can eliminate short fragments of contaminating DNA more effectively. Lengthy autoclave or UV irradiation treatments are required. Depending on bulb power, a UV crosslinker may take a minimum of 2h to achieve an effective dose for elimination of nanogram quantities of contaminating DNA (>7250mJ/cm(2)). Similarly autoclaving may also take 2h to eliminate similar quantities of contaminating DNA. For this study, we used dried saliva stains to determine the effective dose. Dried saliva stains were chosen because purified DNA as well as fresh saliva are less difficult to eradicate than dried stains and also because consumable contamination is more likely to be in the form of a collection of dry cells.

  15. Autoclave and beta-amylolysis lead to reduced in vitro digestibility of starch. (United States)

    Hickman, B Elliot; Janaswamy, Srinivas; Yao, Yuan


    In this study, a combination of autoclave and beta-amylolysis was used to modulate the digestibility of normal corn starch (NCS) and wheat starch (WS). The modification procedure comprised three cycles of autoclave at 35% moisture content and 121 degrees C, beta-amylolysis, and one additional cycle of autoclave. Starch materials were sampled at each stage and characterized. The fine structure of starch was determined using high-performance size-exclusion chromatography, the micromorphology of starch dispersion was imaged using cryo-SEM, the crystalline pattern was evaluated using wide-angle X-ray powder diffraction, and the digestibility was measured using Englyst assay. After beta-amylolysis, amylose was enriched (from 25.4 to 33.2% for NCS and from 27.5 to 32.8% for WS) and the branch density was increased (from 5.2 to 7.7% for NCS and from 5.3 to 7.9% for WS). Cryo-SEM images showed that the autoclave treatment led to the formation of a low-swelling, high-density gel network, whereas beta-amylolysis nearly demolished the network structure. The loss of A-type crystalline structure and the formation of B- and V-type structures resulted from autoclave, which suggests the formation of amylose-based ordered structure. Englyst assay indicated that, due to beta-amylolysis, the resistant starch (RS) content was increased to 30 from 11% of native NCS and to 23 from 9% of native WS. In contrast, autoclave showed only minor impact on RS levels. The increase of RS observed in this study is associated with enhanced branch density, which is different from the four types of RS commonly defined.

  16. Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles. (United States)

    Neumann, Oara; Feronti, Curtis; Neumann, Albert D; Dong, Anjie; Schell, Kevin; Lu, Benjamin; Kim, Eric; Quinn, Mary; Thompson, Shea; Grady, Nathaniel; Nordlander, Peter; Oden, Maria; Halas, Naomi J


    The lack of readily available sterilization processes for medicine and dentistry practices in the developing world is a major risk factor for the propagation of disease. Modern medical facilities in the developed world often use autoclave systems to sterilize medical instruments and equipment and process waste that could contain harmful contagions. Here, we show the use of broadband light-absorbing nanoparticles as solar photothermal heaters, which generate high-temperature steam for a standalone, efficient solar autoclave useful for sanitation of instruments or materials in resource-limited, remote locations. Sterilization was verified using a standard Geobacillus stearothermophilus-based biological indicator.

  17. Bisphenol-A: an estrogenic substance is released from polycarbonate flasks during autoclaving. (United States)

    Krishnan, A V; Stathis, P; Permuth, S F; Tokes, L; Feldman, D


    In studies to determine whether Saccharomyces cerevisiae produced estrogens, the organism was grown in culture media prepared using distilled water autoclaved in polycarbonate flasks. The yeast-conditioned media showed the presence of a substance that competed with [3H]estradiol for binding to estrogen receptors (ER) from rat uterus. However, it soon became clear that the estrogenic substance in the conditioned media was not a product of the yeast grown in culture, but was leached out of the polycarbonate flasks during the autoclaving procedure. [3H]Estradiol displacement activity was monitored by ER RRA, and the active substance was purified from autoclaved medium using a series of HPLC steps. The final purified product was identified as bisphenol-A (BPA) by nuclear magnetic resonance spectroscopy and mass spectrometry. BPA could also be identified in distilled water autoclaved in polycarbonate flasks without the requirement of either the organism or the constituents of the culture medium. Authentic BPA was active in competitive RRAs, demonstrating an affinity approximately 1:2000 that of estradiol for ER. In functional assays, BPA (10-25 nM) induced progesterone receptors in cultured human mammary cancer cells (MCF-7) at a potency of approximately 1:5000 compared to that of estradiol. The BPA effect on PR induction was blocked by tamoxifen. In addition, BPA (25 nM) increased the rate of proliferation of MCF-7 cells assessed by [3H]thymidine incorporation. Thus, BPA exhibited estrogenic activity by both RRA and two functional bioresponse assays. Finally, MCF-7 cells grown in media prepared with water autoclaved in polycarbonate exhibited higher progesterone receptor levels than cells.grown in media prepared with water autoclaved in glass, suggesting an estrogenic effect of the water autoclaved in polycarbonate. Our findings raise the possibility that unsuspected estrogenic activity in the form of BPA may have an impact on experiments employing media autoclaved in

  18. Modeling HIV Cure (United States)

    Perelson, Alan; Conway, Jessica; Cao, Youfang

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

  19. Production technology of low silicon iron copper tailings autoclaved brick%低硅铜铁尾矿生产蒸压砖的技术研究

    Institute of Scientific and Technical Information of China (English)

    邓景明; 唐怀志


      以低硅铜铁尾矿为主要原料,掺入适量矿渣、铜渣、硅铝酸盐、硫酸盐、碳酸盐组成的固化剂经过加压成型后,在183℃温度的蒸压养护下制成标准砖,该砖平均抗压强度达到13.6 MPa,抗冻性能指标合格,固体废弃物利用率达到90%以上.%The paper introduces a kind of autoclaved brick, which is made of low silicon copper iron tailings as a main raw material, and appropriate mixture of amount of slag, copper slag, aluminosilicate, sulfates, carbonates as curing agent. The mixture is pressed into brick and cured at 183 ℃, which can reach 13.6 MPa of average compressive strength and qualified frost resistance index.

  20. Biofiltration of Methane from Ruminants Gas Effluent Using Autoclaved Aerated Concrete as the Carrier Material

    NARCIS (Netherlands)

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Peiren, Nico; De Campeneere, Sam; Ho, Adrian; Boon, Nico


    Abstract The performance of Methane-Oxidizing Bacteria (MOB) immobilized on Autoclaved Aerated Concrete (AAC) in a biofilter setup to remove methane from ruminants gas effluent was investigated. Two dairy cows were housed in respiration chambers for two days where the exhaust gas from the chambers w

  1. Effects of autoclaving and pullulanase debranching on the resistant starch yield of normal maize starch

    Directory of Open Access Journals (Sweden)



    Full Text Available In this study, resistant starch (RS, type 3, was prepared by the autoclaving and debranching of normal maize starch isolated from a selected ZP genotype. The objectives of this study were to optimize both starch autoclaving and debranching with pullulanase (PromozymeBrewQ for the production of RS. Autoclaving at 120 °C (30 min increased the RS content of all samples, whereas freezing at –20 °C did not have an obvious effect on the RS contents. The highest RS yield in the autoclaved starch samples was 7.0 % after three autoclaving–cooling cycles. After pullulanase debranching at 50 °C and retrogradation at 4 °C, the RS yields ranged from 10.2 to 25.5 % in all samples (depending on the hydrolysis time. Debranched starch samples with a maximum RS yield of 25.5 % were obtained after a debranching time of 24 h. This study showed that starch from the selected ZP maize genotype is suitable for pullulanase treatment and RS preparation but that additional studies with a greater number of different treatments (incubation time/temperature are necessary to manipulate and promote crystallization and enhance RS formation.

  2. Thermal properties of Poly(ethylene terephthalate) recovered from municipal solid waste by steam autoclaving (United States)

    The goal of this study was to evaluate the effects of steam autoclaving on the properties of PET, data which could ultimately be applied to determine the most likely end use of this potentially huge waste stream. Through the course of the study it was determined that stretch blow molding in bottle ...

  3. Control over Particle Size Distribution by Autoclaving Poloxamer-Stabilized Trimyristin Nanodispersions. (United States)

    Göke, Katrin; Roese, Elin; Arnold, Andreas; Kuntsche, Judith; Bunjes, Heike


    Lipid nanoparticles are under investigation as delivery systems for poorly water-soluble drugs. The particle size in these dispersions strongly influences important pharmaceutical properties like biodistribution and drug loading capacity; it should be below 500 nm for direct injection into the bloodstream. Consequently, small particles with a narrow particle size distribution are desired. Hitherto, there are, however, only limited possibilities for the preparation of monodisperse, pharmaceutically relevant dispersions. In this work, the effect of autoclaving at 121 °C on the particle size distribution of lipid nanoemulsions and -suspensions consisting of the pharmaceutically relevant components trimyristin and poloxamer 188 was studied. Additionally, the amount of emulsifier needed to stabilize both untreated and autoclaved particles was assessed. In our study, four dispersions of mean particle sizes from 45 to 150 nm were prepared by high-pressure melt homogenization. The particle size distribution before and after autoclaving was characterized using static and dynamic light scattering, differential scanning calorimetry, and transmission electron microscopy. Asymmetrical flow field-flow fractionation was used for particle size distribution analyses and for the determination of free poloxamer 188. Upon autoclaving, the mean particle size increased to up to 200 nm, but not proportionally to the initial size. At the same time, the particle size distribution width decreased remarkably. Heat treatment thus seems to be a promising approach to achieve the desired narrow particle size distribution of such dispersions. Related to the lipid content, suspension particles needed more emulsifier for stabilization than emulsion droplets, and smaller particles more than larger ones.


    Directory of Open Access Journals (Sweden)



    Full Text Available Ce travail présente une étude expérimentale du comportement mécanique du béton cellulaire autoclavé. L’étude est portée essentiellement sur une série d’essais mécaniques en compression quasistatique à différentes vitesses de déformation variables entre 10-4 s-1 et 10 s-1 et à deux états différents (état sec et état saturé d’eau. En général, l’augmentation de la vitesse de déformation donne une augmentation de la contrainte critique du béton cellulaire autoclavé. Le béton cellulaire autoclavé présente une sensibilité à la vitesse de déformation positive. La valeur du module d’élasticité est proche de la valeur standard (1.5 GPa pour un béton cellulaire autoclavé de masse volumique égale à 500-550 kg/m3.

  5. Biochemical methane potential tests of different autoclaved and microwaved lignocellulosic organic fractions of municipal solid waste. (United States)

    Pecorini, Isabella; Baldi, Francesco; Carnevale, Ennio Antonio; Corti, Andrea


    The aim of this research was to enhance the anaerobic biodegradability and methane production of two synthetic Organic Fractions of Municipal Solid Waste with different lignocellulosic contents by assessing microwave and autoclave pre-treatments. Biochemical Methane Potential assays were performed for 21days. Changes in the soluble fractions of the organic matter (measured by soluble chemical oxygen demand, carbohydrates and proteins), the first order hydrolysis constant kh and the cumulated methane production at 21days were used to evaluate the efficiency of microwaving and autoclaving pretreatments on substrates solubilization and anaerobic digestion. Microwave treatment led to a methane production increase of 8.5% for both the tested organic fractions while autoclave treatment had an increase ranging from 1.0% to 4.4%. Results showed an increase of the soluble fraction after pre-treatments for both the synthetic organic fractions. Soluble chemical oxygen demand observed significant increases for pretreated substrates (up to 219.8%). In this regard, the mediocre results of methane's production led to the conclusion that autoclaving and microwaving resulted in the hydrolysis of a significant fraction of non-biodegradable organic substances recalcitrant to anaerobic digestion.

  6. Autoclave reduction of jarosites and other metal sulfates : a new approach to major waste problems

    NARCIS (Netherlands)

    Hage, J.T.L.


    Industrial jarosite is a waste product of the zinc industry. It is considered a serious environmental problem, due to the quantity produced and the mobile hazardous metals it contains. Over 50 million tons are already stored worldwide. The jarosite sludge autoclave treatment process described in thi

  7. Synthesis and characterization of strontium carboxylates at room temperature and at high temperature in autoclave vessels

    DEFF Research Database (Denmark)

    Christgau, Stephan; Ståhl, Kenny; Andersen, Jens Enevold Thaulov


    -ray crystallography. Optimum conditions were found at T = 120-1400C, a base-to-acid ratio of 1.2 and 15 min. of reaction-time in an autoclave vessel. Large crystals were readily obtained within a time period of hours. The crystal structures of strontium D-glutamate hexahydrate (I) and strontium di-(hydrogen L...

  8. Utilization of squid pen for the efficient production of chitosanase and antioxidants through prolonged autoclave treatment. (United States)

    Wang, San-Lang; Wu, Pei-Chen; Liang, Tzu-Wen


    We have developed a culture system for efficient production of chitosanase by Bacillus sp. TKU004. TKU004 was cultivated by using squid pen powder as the sole carbon/nitrogen source. The effects of autoclave treatments of the medium on the production of chitosanase were investigated. Autoclave treatment of squid pen powder for 45 min remarkably promoted enzyme productivity. When the culture medium containing an initial squid pen powder concentration of 3% was autoclaved for 45 min, the chitosanase activity was optimal and reached 0.14-0.16 U/mL. In addition, extracellular surfactant-stable chitosanase was purified from the TKU004 culture supernatant. The antioxidant activity of TKU004 culture supernatant was determined through the scavenging ability of DPPH, with 70% per mL. With this method, we have shown that marine wastes can be utilized efficiently through prolonged autoclave treatments to generate a high value-added product, and have revealed its hidden potential in the production of functional foods.

  9. Effects of autoclaving on the proximate composition of stored castor (Ricinus communis seeds

    Directory of Open Access Journals (Sweden)



    Full Text Available Negedu A, Ameh JB, Umoh VJ, Atawodi SE, Rai MK. 2013. Effects of autoclaving on the proximate composition of stored castor (Ricinus communis seeds. Nusantara Bioscience 5: 51-56. The effect of autoclaving on the proximate composition, free fatty acids and peroxide value of castor (Ricinus communis L. seeds in storage were studied. Seeds of castor were surface sterilized, dried and divided into two equal sets of 300g each. One set was autoclaved at 15 1b pressure for 30 minutes at 121oC and the other set served as control. Each set was prepared in triplicates and both sets were stored under same room temperature conditions for a period of 180 days and agitated intermittently. Analysis of the proximate composition showed that autoclaving treatment caused an increased total fat content, reduced moisture, protein, nitrogen free extract (soluble sugar and ash contents of the seeds in storage, as well as a non-significant increase in crude fiber (non-soluble sugar content. It increased the free fatty acid content and decreased the peroxide value of seed oil.

  10. NONA Cure of Prepreg Structures Project (United States)

    National Aeronautics and Space Administration — CRG's no-oven, no-autoclave (NONA) composite processing technology enables the fabrication of high-performance composite parts without the limitations imposed by...

  11. Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

    Directory of Open Access Journals (Sweden)

    Xiao-Cui Gong

    Full Text Available Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR. However, it is not entirely clear if "endogenous" bacteria (e.g., spores in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain. The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

  12. Composite Cryotank Technologies and Development 2.4 and 5.5M out of Autoclave Tank Test Results (United States)

    Jackson, Justin R.; Vickers, John; Fikes, John


    The Composite Cryotank Technologies and Demonstration (CCTD) project substantially matured composite, cryogenic propellant tank technology. The project involved the design, analysis, fabrication, and testing of large-scale (2.4-m-diameter precursor and 5.5-m-diameter) composite cryotanks. Design features included a one-piece wall design that minimized tank weight, a Y-joint that incorporated an engineered material to alleviate stress concentration under combined loading, and a fluted core cylindrical section that inherently allows for venting and purging. The tanks used out-of-autoclave (OoA) cured graphite/epoxy material and processes to enable large (up to 10-m-diameter) cryotank fabrication, and thin-ply prepreg to minimize hydrogen permeation through tank walls. Both tanks were fabricated at Boeing using automated fiber placement on breakdown tooling. A fluted core skirt that efficiently carried axial loads and enabled hydrogen purging was included on the 5.5-m-diameter tank. Ultrasonic inspection was performed, and a structural health monitoring system was installed to identify any impact damage during ground processing. The precursor and 5.5-m-diameter tanks were tested in custom test fixtures at the National Aeronautics and Space Administration Marshall Space Flight Center. The testing, which consisted of a sequence of pressure and thermal cycles using liquid hydrogen, was successfully concluded and obtained valuable structural, thermal, and permeation performance data. This technology can be applied to a variety of aircraft and spacecraft applications that would benefit from 30 to 40% weight savings and substantial cost savings compared to aluminum lithium tanks.

  13. Controversies in HIV cure research

    Directory of Open Access Journals (Sweden)

    Johnston Rowena


    Full Text Available Abstract Background Antiretroviral therapy significantly reduces HIV viral burden and prolongs life, but does not cure HIV infection. The major scientific barrier to a cure is thought to be the persistence of the virus in cellular and/or anatomical reservoirs. Discussion Most efforts to date, including pharmaco, immuno or gene therapy, have failed to cure patients, with the notable exception of a stem cell transplant recipient commonly known as the Berlin patient. This case has revived interest in the potential to cure HIV infection and has highlighted the need to resolve critical questions in the basic, pre-clinical and clinical research spheres as they pertain specifically to efforts to eradicate HIV from the body of an infected person (a sterilizing cure or at least render the need for lifelong antiretroviral therapy obsolete (functional cure. This paper describes ongoing debates in each of these research spheres as they were presented and discussed at a satellite session that took place at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Rome in July 2011. Summary The resolution of these debates may have important implications for the search for a cure, the most efficient ways to identify and test promising interventions, and ultimately the availability of such a cure to diverse groups of HIV patients around the world.


    Directory of Open Access Journals (Sweden)

    Pınar GÜLTEKİN


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

  15. Elevated Temperature, Notched Compression Performance of Out of Autoclave Processed Composites (United States)

    Grimsley, Brian W.; Sutter, James K.; Dixon, Genevieve D.; Smeltzer, Satn S.


    Curved honeycomb sandwich panels composed of carbon fiber reinforced toughened-epoxy polymer facesheets are being evaluated for potential use as payload fairing components on the NASA heavy-lift space launch system (HL-SLS). These proposed composite sandwich panels provide the most efficient aerospace launch structures, and offer mass and thermal advantages when compared with existing metallic payload fairing structures. NASA and industry are investigating recently developed carbon fiber epoxy prepreg systems which can be fabricated using out-of autoclave (OOA) processes. Specifically, OOA processes using vacuum pressure in an oven and thereby significantly reducing the cost associated with manufacturing large (up to 10 m diameter) composite structures when compared with autoclave. One of these OOA composite material systems, CYCOM(R) 5320-1, was selected for manufacture of a 1/16th scale barrel portion of the payload fairing; such that, the system could be compared with the well-characterized prepreg system, CYCOM(R) 977-3, typically processed in an autoclave. Notched compression coupons for each material were obtained from the minimum-gauge flat laminate [60/-60/0]S witness panels produced in this manufacturing study. The coupons were also conditioned to an effective moisture equilibrium point and tested according to ASTM D6484M-09 at temperatures ranging from 25 C up to 177 C. The results of this elevated temperature mechanical characterization study demonstrate that, for thin coupons, the OHC strength of the OOA laminate was equivalent to the flight certified autoclave processed composite laminates; the limitations on the elevated temperature range are hot-wet conditions up to 163 C and are only within the margins of testing error. At 25 C, both the wet and dry OOA material coupons demonstrated greater OHC failure strengths than the autoclave processed material laminates. These results indicate a substantial improvement in OOA material development and

  16. MODIFIKASI PATI GARUT (Marantha arundinacea) DENGAN PERLAKUAN SIKLUS PEMANASAN SUHU TINGGI-PENDINGINAN ( AUTOCLAVING-COOLING CYCLING) UNTUK MENGHASILKAN PATI RESISTEN TIPE III [Arrowroot (Marantha arundinacea) Starch Modification Through Autoclaving-Cooling Cycling Treatment to Produce Resistant Starch Type III


    Sugiyono*; Ratih Pratiwi2); Didah Nur Faridah


    The objectives of this research were to modify arrowroot starch to produce resistant starch type III by autoclaving-cooling cycling and to characterize the modified arrowroot starches according to their chemical properties. The research consisted of three steps : arrowroot extraction, starch modification, and chemical characterization. The extraction of arrowroot produced 10.78% starch. Starch modification by autoclaving-cooling cycle(s) was run in 6 different treatments with the aim of obser...

  17. Novel techniques for concrete curing

    DEFF Research Database (Denmark)

    Kovler, Konstantin; Jensen, Ole Mejlhede


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

  18. Dimensional stability of a polyvinylsiloxane impression material following ethylene oxide and steam autoclave sterilization. (United States)

    Holtan, J R; Olin, P S; Rudney, J D


    Polyvinlsiloxane impressions were made from a stainless steel master die machined to stimulate five full veneer crown preparations symmetrically placed in an arch form. Three groups of 10 impressions each were made. Treatment groups were sterilized using an ethylene oxide gas and a conventional steam autoclave. Casts were poured and intrapreparation, height, and diameter measurements were made using a stereomicroscope, a digital electronic caliper, and a 1-inch travel dial indicator. Analysis of dimensional changes for the two groups showed that casts made from impressions sterilized by ethylene oxide are acceptable for use in the construction of fixed or removable prostheses. Casts made from impressions sterilized in a steam autoclave can be used for the fabrication of diagnostic casts and some transitional prostheses, but not for routine construction of crowns or fixed partial dentures.

  19. HYACE - a novel autoclave coring equipment for systematic offshore gashydrate sampling

    Energy Technology Data Exchange (ETDEWEB)

    Amann, H.; Hohnberg, H.J.; Reinelt, R. [Technische Univ. Berlin (Germany). Inst. fuer Schiffs- und Meerestechnik, Fachgebiet Maritime Technik


    HYACE, the acronym for hydrate autoclave coring equipment system, is a research and development project sponsored by the European Union`s Marine Science and Technology Programme MAST. The project was to have started in the fourth quarter of 1997 and is to last 30 months. The main activities of the project will be in the development and prototype testing of an innovative down-hole controlled autoclave coring system. This system will be designed to sample marine sediments at extended down-hole conditions maintaining as many parameters constant as possible. In general terms, the main aim of the project is to contribute to systematic ground truthing of a necessarily ephemeral phenomenon of growing global significance: sampling and analysis of gas hydrates in their natural environment. (MSK)

  20. Torsional properties of stainless-steel and nickel-titanium files after multiple autoclave sterilizations. (United States)

    Hilt, B R; Cunningham, C J; Shen, C; Richards, N


    This study tested the hypothesis that multiple sterilizations of endodontic stainless-steel and nickel-titanium files will lead to a continuous decrease in the resistance of files to separation by torsion. One hundred stainless-steel and 100 nickel-titanium #30 K-type files were divided into 20 groups of 10 and sterilized in increments of 10 cycles, using a full cycle and a fast cycle autoclave. These files were tested by twisting each of them in a clockwise direction until fracture (torque g-cm). Samples of the fractured files were embedded in an epoxy resin and polished for Knoop hardness tests. In addition, the samples were chemically etched to reveal changes in microstructure. The findings of this study indicate that neither the number of sterilization cycles nor the type of autoclave sterilization used affects the torsional properties, hardness, and microstructure of stainless-steel and nickel-titanium files.


    Directory of Open Access Journals (Sweden)

    Z. Owsiak


    Full Text Available This paper presents the results from the tests of autoclaved aerated concrete with halloysite as a cement additive. Good pozzolanic properties make it a suitable material to be used as a partial replacement of a portion of cement. Basic physical and mechanical properties of the composites with various mineral content are discussed. The compressive strength test results indicate an increase in strength of the AAC containing 2.5 % and 5 % halloysite relative to the reference specimen. Thermal conductivity and density values remained at the same level. Observations of the microstructure in the scanning electron microscope confirmed the results from the XRD tests. Anhydrite was observed in addition to tobermorite. The results from the tests of the autoclaved aerated concretes in which halloysite was incorporated as 7.5 % and 10 % cement replacement showed an increase in compressive strength, density and thermal conductivity values.

  2. Correlation of cure monitoring techniques (United States)

    Chang, S. S.; Mopsik, F. I.; Hunston, D. L.

    Six different composite matrix or neat resin cure-monitoring methods are presently used to follow the cure process in a model epoxy system, and the results obtained are compared. Differential scanning calorimetry, viscosity monitoring, the ultrasonic shear wave propagation technique, dielectric spectrometry, and two different fluorescence intensity techniques are compared with a view to common traits and differences. Dielectric fluorescence and ultrasonic measurement techniques are noted to be applicable to on-line process monitoring.

  3. Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy


    Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman


    Introduction: Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). Methods and Materials: In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autocla...

  4. Multiple autoclave cycles affect the surface of rotary nickel-titanium files: an atomic force microscopy study. (United States)

    Valois, Caroline R A; Silva, Luciano P; Azevedo, Ricardo B


    The purpose of this study was to evaluate the surface of rotary nickel-titanium (Ni-Ti) files after multiple autoclave cycles. Two different types of rotary Ni-Ti (Greater Taper and ProFile) were attached to a glass base. After 1, 5, and 10 autoclave cycles the files were positioned in the atomic force microscope. The analyses were performed on 15 different points. The same files were used as control before any autoclave cycle. The following vertical topographic parameters were measured: arithmetic mean roughness, maximum height, and root mean square. The differences were tested by analysis of variance with Tukey test. All topographic parameters were higher for both Greater Taper and ProFile after 10 cycles compared with the control (P autoclave cycles increase the depth of surface irregularities located on rotary Ni-Ti files.

  5. Achieving appropriate design for developing world heath care: the case of a low-cost autoclave for primary health clinics. (United States)

    Cho, Hallie S; Tao, Gregory D; Winter, Amos


    In developing world health clinics, incidence of surgical site infection is 2 to 10 times higher than in developed world hospitals. This paper identifies lack of availability of appropriately designed, low-cost autoclaves in developing world health clinics as a major contributing factor to the dramatic gap in surgical site infection rates. The paper describes the process of developing a low-cost autoclave that addresses the unique challenges faced by developing world primary health clinics and discusses how appropriateness of design was determined. The resulting pressure cooker-based autoclave design was fabricated and tested against the CDC specifications. Twelve partnering clinics in Nepal trialed these autoclaves from July until December 2012.

  6. Autoclaved Tumor Bone for Skeletal Reconstruction in Paediatric Patients: A Low Cost Alternative in Developing Countries

    Directory of Open Access Journals (Sweden)

    Masood Umer


    Full Text Available We reviewed in this series forty patients of pediatric age who underwent resection for malignant tumors of musculoskeletal system followed by biological reconstruction. Our surgical procedure for reconstruction included (1 wide en bloc resection of the tumor; (2 curettage of tumor from the resected bone; (3 autoclaving for 8 minutes (4 bone grafting from the fibula (both vascularized and nonvascularized fibular grafts used; (5 reimplantation of the autoclaved bone into the host bone defect and fixation with plates. Functional evaluation was done using MSTS scoring system. At final followup of at least 18 months (mean 29.2 months, 31 patients had recovered without any complications. Thirty-eight patients successfully achieved a solid bony union between the graft and recipient bone. Three patients had surgical site infection. They were managed with wound debridement and flap coverage of the defect. Local recurrence and nonunion occurred in two patients each. One patient underwent disarticulation at hip due to extensive local disease and one died of metastasis. For patients with non-union, revision procedure with bone graft and compression plates was successfully used. The use of autoclaved tumor grafts provides a limb salvage option that is inexpensive and independent of external resources and is a viable option for musculoskeletal tumor management in developing countries.

  7. Role of the wireless thermologger system in the management of the autoclave unequipped with sensor ports. (United States)

    Uetera, Yushi; Shigematsu, Hiroshi; Baba, Zenzou; Kumada, Naohito; Kawamura, Kunio


    Recently, the wireless thermologger system was developed. It consists of a wireless logger and the attached computer system. The wireless logger has a wireless structure and can be placed anywhere in the sterilizer chamber for thermometry. In the present study, thermal evaluations were performed twice using the wireless thermologger system in the sterilizer chamber of the prevacuum autoclave unequipped with sensor ports when it failed to pass the Bowie-Dick test and underwent mechanical repairs. Thermometry was performed when the Bowie-Dick test cycle was operated. The heat up time was measured in the range of 120.0-134.0 degrees C. The F0 value was calculated with the reference temperature at 121.0 degrees C and Z value at 10 degrees C when the sterilization temperature was over 120.0 degrees C. The first thermal evaluation was performed after three air-leaking points were repaired along with the replacement of the vacuum pump and the thermosensor. It revealed that the heat-up time was 4 min and 42 s and the F0 value was 137.5. After the temperature control systems were adjusted using the process calibrator in the prevacuum autoclave, the second thermal evaluation revealed that the heat up time was 2 mins 1 s and the F0 value was 102.7. The present study suggests that the wireless thermologger system is useful in the management of the autoclave unequipped with sensor ports when it undergoes mechanical repairs.

  8. Pressure impact of autoclave treatment on water sorption and pectin composition of flax cellulosic-fibres. (United States)

    Alix, S; Colasse, L; Morvan, C; Lebrun, L; Marais, S


    The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In order to reduce the water absorption of this non-woven technical fibres, an autoclave treatment was performed which was expected to remove the pectins and then to reduce the water sorption on their negative charges. The impact of autoclave pressure (0.5, 1 and 2 bars) on water sorption was investigated by using a gravimetric static equilibrium method. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. The lowest pressure treatments impacted only the Langmuir contribution while the 2 bar autoclave-treatment positively impacted the water resistance in the core of fibres by reducing Henry's absorption rate. This was shown to be related to the chemical modifications at the surface and in the core of fibres. A schematic model is presented relating the water sorption and the pectic composition of the fabric.

  9. Autoclave method for rapid preparation of bacterial PCR-template DNA. (United States)

    Simmon, Keith E; Steadman, Dewey D; Durkin, Sarah; Baldwin, Amy; Jeffrey, Wade H; Sheridan, Peter; Horton, Rene; Shields, Malcolm S


    An autoclave method for preparing bacterial DNA for PCR template is presented, it eliminates the use of detergents, organic solvents, and mechanical cellular disruption approaches, thereby significantly reducing processing time and costs while increasing reproducibility. Bacteria are lysed by rapid heating and depressurization in an autoclave. The lysate, cleared by microcentrifugation, was either used directly in the PCR reaction, or concentrated by ultrafiltration. This approach was compared with seven established methods of DNA template preparation from four bacterial sources which included boiling Triton X-100 and SDS, bead beating, lysozyme/proteinase K, and CTAB lysis method components. Bacteria examined were Enterococcus and Escherichia coli, a natural marine bacterial community and an Antarctic cyanobacterial-mat. DNAs were tested for their suitability as PCR templates by repetitive element random amplified polymorphic DNA (RAPD) and denaturing gradient gel electrophoresis (DGGE) analysis. The autoclave method produced PCR amplifiable template comparable or superior to the other methods, with greater reproducibility, much shorter processing time, and at a significantly lower cost.

  10. Influence of autoclave sterilization on the surface parameters and mechanical properties of six orthodontic wires. (United States)

    Pernier, C; Grosgogeat, B; Ponsonnet, L; Benay, G; Lissac, M


    Orthodontic wires are frequently packaged in individual sealed bags in order to avoid cross-contamination. The instructions on the wrapper generally advise autoclave sterilization of the package and its contents if additional protection is desired. However, sterilization can modify the surface parameters and the mechanical properties of many types of material. The aim of this research was to determine the influence of one of the most widely used sterilization processes, autoclaving (18 minutes at 134 degrees C, as recommended by the French Ministry of Health), on the surface parameters and mechanical properties of six wires currently used in orthodontics (one stainless steel alloy: Tru-Chrome RMO; two nickel-titanium shape memory alloys: Neo Sentalloy and Neo Sentalloy with Ionguard GAC; and three titanium-molybdenum alloys: TMA(R) and Low Friction TMA Ormco and Resolve GAC). The alloys were analysed on receipt and after sterilization, using surface structure observation techniques, including optical, scanning electron and atomic force microscopy and profilometry. The mechanical properties were assessed by three-point bending tests. The results showed that autoclave sterilization had no adverse effects on the surface parameters or on the selected mechanical properties. This supports the possibility for practitioners to systematically sterilize wires before placing them in the oral environment.

  11. Impact of autoclave sterilization on the activity and structure of formulated heparin. (United States)

    Beaudet, Julie M; Weyers, Amanda; Solakyildirim, Kemal; Yang, Bo; Takieddin, Majde; Mousa, Shaker; Zhang, Fuming; Linhardt, Robert J


    The stability of a formulated heparin was examined during its sterilization by autoclaving. A new method to follow loss in heparin binding to the serine protease inhibitor, antithrombin III, and the serine protease, thrombin, was developed using a surface plasmon resonance competitive binding assay. This loss in binding affinity correlated well with loss in antifactor IIa (thrombin) activity as well as antifactor Xa activity as measured using conventional amidolytic assays. Autoclaving also resulted in a modest breakdown of the heparin backbone as confirmed by a slight reduction in number-averaged and weight-averaged molecular weight and an increase in polydispersity. Although no clear changes were observed by nuclear magnetic resonance spectroscopy, disaccharide composition analysis using high-performance liquid chromatography-electrospray ionization-mass spectrometry suggested that loss of selected sulfo groups had taken place. It is this sulfo group loss that probably accounts for a decrease in the binding of autoclaved heparin to antithrombin III and thrombin as well as the observed decrease in its amidolytic activity.

  12. Curing units' ability to cure restorative composites and dual-cured composite cements under composite overlay. (United States)

    Park, Sung-Ho; Kim, Su-Sun; Cho, Yong-Sik; Lee, Chang-Kyu; Noh, Byng-Duk


    This study compared the efficacy of using conventional low-power density QTH (LQTH) units, high-power density QTH (HQTH) units, argon (Ar) laser and Plasma arc curing (PAC) units for curing dual-cured resin cements and restorative resin composites under a pre-cured resin composite overlay. The microhardness of the two types of restorative resins (Z100 and Tetric Ceram) and a dual-cured resin cement (Variolink II) were measured after they were light cured for 60 seconds in a 2 mm Teflon mold. The recorded microhardness was determined to be the optimum microhard-ness (OM). Either one of the two types of restorative resins (Z100, Tetric Ceram) or the dual cured resin cement (Variolink II) were placed under a 1.5-mm thick and 8 mm diameter pre-cured Targis (Vivadent/Ivoclar AG, Schaan, Liechtenstein) overlay. The specimens that were prepared for each material were divided into four groups depending upon the curing units used (HQTH, PAC, Laser or LQTH) and were further subdi-vided into subgroups according to light curing time. The curing times used were 30, 60, 90 and 120 seconds for HQTH; 12, 24, 36 and 48 seconds for the PAC unit; 15, 30, 45 and 60 for the Laser and 60, 120 or 180 seconds for the LQTH unit. Fifteen specimens were assigned to each sub- group. The microhardness of the upper and and lower composite surfaces under the Targis overlay were measured using an Optidur Vickers hardness-measuring instrument (Göttfert Feinwerktechnik GmbH, Buchen, Germany). In each material, for each group, a three-way ANOVA with Tukey was used at the 0.05 level of significance to compare the microhardnesses of the upper and lower composite surfaces and the previously measured OM of the material. From the OM of each material, 80% OM was calculated and the time required for the microhardness of the upper and lower surface of the specimen to reach 100% and 80% of OM was determined. In Z100 and Tetric Ceram, when the composites were light cured for 120 seconds using the HQTH lamp

  13. West Angeles Community Development Corporation final technical report on export market feasibility planning and research for the solar medical autoclave

    Energy Technology Data Exchange (ETDEWEB)

    Power, G.D.


    This report summarizes core findings from an investigation performed by the staff of West Angeles Community Development Corporation (CDC) regarding the feasibility of marketing the Solar Medical Autoclave (``autoclave``) in South Africa. The investigation was completed during 1997, the period prescribed by the Grant Award made by the U.S. Department of Energy on January 1, 1997, and was monitored by the National Renewable Energy Laboratory.

  14. Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness

    Directory of Open Access Journals (Sweden)

    Carola Esposito Corcione


    Full Text Available The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was also deeply investigated. A highly exothermal reaction, based on a self-activated frontal polymerization reaction, was supposed and verified trough a suitable temperature signal acquisition system, specifically realized for this measurement. This is one of the first studies carried out on the curing behavior of these peculiar cold-cured epoxy resins as a function of curing time and thickness.

  15. Curing efficiency of various types of light-curing units. (United States)

    Rahiotis, Chris; Kakaboura, Afrodite; Loukidis, Michalis; Vougiouklakis, George


    This study compared monomer conversion (DC), the per cent linear polymerization shrinkage (%LS), the wall-to-wall contraction pattern (per cent of peripheral opening, %DM, and maximal marginal gap, MG) and depth of cure (DOC), of a hybrid resin composite (Spectrum TPH) exposed to different types of light-curing units and exposure modes (Virtuoso-PAC, Elipar TriLight-QTH, and FreeLight-LED). The QTH and LED units were used in two curing modes: the exponential ramp and the continuous output modes. Monomer conversion was investigated by micro Multiple Internal Reflection (MIR)-Fourier-transform infrared (FTIR) spectroscopy and %LS was measured by the deflective disc method. The wall-to-wall contraction method used a cylindrical cavity model in extracted human teeth. The per cent debonded margins relative to the cavity periphery (%DM) and the width of maximum gap (MG) was evaluated. The DOC was determined using Vickers microhardness measurements (200 g load, 20 s) at the top surface (H0), at 2 mm (H2) and at 4 mm (H4) depths, and the results expressed as H2/H0 and H4/H0 ratios. Significantly lower %DC and %LS values were provided by PAC and LED units. No differences were found in %DM among the curing units and PAC exhibited the highest MG. No significant differences were noted among light-curing groups in terms of H2/H0 microhardness values. The QTH, operated in exponential mode, resulted in the highest H4/H0 value. The exponential mode of the QTH demonstrated superior performance for the total of the characteristics evaluated.

  16. Evaluation of the effect of inactivation by microwave and autoclave in homeopathic medicines

    Directory of Open Access Journals (Sweden)

    Carlos Moacir Bonato


    Full Text Available Background: The Brazilian Pharmacopoeia defines the sterilization process as a "method" intended to remove or destroy all forms of life, animal or plant, macroscopic or microscopic, saprophytic or not, present in the product concerned, without ensuring the complete inactivation of toxins or cellular enzymes. Microwaves are electromagnetic waves with frequencies ranging between 300MHz (300x106 Hz and 300 GHz (300x109 Hz and wavelengths from 1 m to 1 mm[1]. They are waves that lie within the region between TV waves and the infrared region within the spectrum of electromagnetic waves. According to the Technical Standards Textbook for Homeopathic Pharmacy, glass tubes may be reused after washed with running and purified water and inactivated by autoclaving at 120oC for 30 minutes or by a dry air buffer at 180oC for 30 minutes or at 140oC for 1 hour [2]. Aims: Current experiment evaluates the influence of ultra-diluted Sulphur with and without inactivation by autoclaving and microwaving for certain variables in the germination and growth of sorghum (Sorghum bicolor L. Moench - cv TX623B. Methodology: Ten milliliters of Sulphur in homeopathic dinamizations (proposed by Hering - DH 9DH, 18DH and 30DH inactivated by microwave and by autoclave heat, and control with water, were added to petri dishes in which 20 sorghum seeds were distributed. The experiment was conducted in a growth chamber (BOD at 25oC and during a 16-h photoperiod. Double-blind methodology to avoid researcher’s possible interferences or trends, coupled to statistic treatment at the end of the experiment, was employed. Data underwent variance analysis and means were compared by Scott-Knott’s test at 5% probability. Results: Homeopathy Sulphur changed the evaluated parameters of 9DH, 18 DH and 30 DH dinamizations when compared to control (water. Differences existed with regard to effects of the different microwave-treated (M9DH, M18DH, M30DH and

  17. Autoclave sterilization produces acrylamide in rodent diets: implications for toxicity testing. (United States)

    Twaddle, Nathan C; Churchwell, Mona I; McDaniel, L Patrice; Doerge, Daniel R


    Acrylamide (AA) is a neurotoxic and carcinogenic contaminant that is formed during the cooking of starchy foods. Assessment of human risks from toxicants is routinely performed using laboratory rodents, and such testing requires careful control of unintended exposures, particularly through the diet. This study describes an analytical method based on liquid chromatography with electrospray tandem mass spectrometry that was used to measure endogenous AA in rodent diets and to survey a number of commercial products for contamination. Method sensitivity permitted accurate quantification of endogenous levels of AA in raw diets below 20 ppb. Autoclaving a standard rodent diet (NIH-31) increased the AA content 14-fold, from 17 to 240 ppb. A nutritionally equivalent diet that was sterilized by irradiation was found to contain approximately 10 ppb of AA (NIH-31IR). A toxicokinetic study of AA and its epoxide metabolite, glycidamide, was performed by switching mice from NIH-31IR to the autoclaved diet for a 30 min feeding period (average AA dose administered was 4.5 microg/kg of body weight). The concentrations of AA and glycidamide were measured in serum collected at various times. The elimination half-lives and the areas under the respective concentration-time curves were similar for AA and glycidamide. Mice maintained on autoclaved NIH-31 diet, but otherwise untreated, showed elevated steady state levels of a glycidamide-derived DNA adduct in liver relative to mice maintained on the irradiated diet. This study demonstrates that a heat sterilization procedure used in laboratory animal husbandry (i.e., autoclaving) can lead to the formation of significant levels of AA in basal diets used for toxicity testing. AA in rodent diets is bioavailable, is distributed to tissues, and is metabolically activated to a genotoxic metabolite, which produces quantifiable cumulative DNA damage. Although the contribution of endogenous AA to the incidence of tumors in multiple organs of

  18. Breather cloth for vacuum curing (United States)

    Reed, M. W.


    Finely-woven nylon cloth that has been treated with Teflon improves vacuum adhesive bonding of coatings to substrates. Cloth is placed over coating; entire assembly, including substrate, coating, and cloth, is placed in plastic vacuum bag for curing. Cloth allows coating to "breathe" when bag is evacuated. Applications include bonding film coatings to solar concentrators and collectors.

  19. Effects of Autoclaving and Mercuric Chloride Sterilization on PAHs Dissipation in a Two-Liquid-Phase Soil Slurry

    Institute of Scientific and Technical Information of China (English)

    WANG Cong-Ying; WANG Fang; WANG Tao; YANG Xing-Lun; BIAN Yong-Rong; F.O.KENGARA; LI Zeng-Bo; JIANG Xin


    A two-liquid-phase (TLP) soil slurry system was employed to quantify the efficiencies of autoclaving and mercuric chloride sterilization in the dissipation of polycyclic aromatic hydrocarbons (PAHs). The fates of 11 PAHs (naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, dibenzo(a, h)anthracene) were recorded over 113 days of incubation. No microorganisms were detected in the HgCl2-sterilized soil slurries during the whole incubation period, indicating very effective sterilization. However, about 2%-36% losses of PAHs were observed in the HgCl2-sterilized slurry. In contrast to the HgCl2-sterilized soil slurry, some microorganisms survived in the autoclaved soil slurries. Moreover,significant biodegradation of 6 PAHs (naphthalene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene) was observed in the autoclaved soil slurries. This indicated that biodegradation results of PAHs in the soil slurries, calculated on basis of the autoclaved control, would be underestimated. It could be concluded that the sterilization efficiency and effectiveness of HgCl2 on soil slurry was much higher than those of autoclaving at 121 ℃ for 45 min.

  20. Autoclave Fully Automatic Feeding and Discharging Can Trolley%杀菌釜全自动进出料台车

    Institute of Scientific and Technical Information of China (English)

    周东; 陈书琼; 陈凯; 林伟杰


    针对八宝粥罐头杀菌茏进出杀菌釜一直由人工完成,存在效率低,劳动强度大,可靠性差的问题,提出了一种杀菌釜全自动进出料台车设计方法.主要设计理念为装满八宝粥罐头的杀菌笼放置在台车轨道上,随台车运送到杀菌釜,杀菌釜内有与台车相对应的运送轨道,通过电机控制两端推块翻转,顺利实现将杀菌笼推进和拉出杀菌釜.%For the end of eight-treasure can bactericidal cage feeding and discharging autoclave had been done manuelly with low efficiency, high labor intensity and poor reliability. This paper put forward a kind of autoclave automatic feeding and discharging can trolley design method. The main design concept is the bactericidal cage full of eight-treasure porridge can be put on the tracks and sent to the autoclave with the trolley. There are tracks in the autoclave corresponding to the trolley with controlled the both ends ejector pads roll-over through the motor, push and pull out the bactericidal cage from autoclave smoothly.

  1. Rapid Development of the Radiation Curing Sector

    Institute of Scientific and Technical Information of China (English)


    @@ Radiation curing is an advanced material surface treatment technology using ultraviolet (UV) radiation and electronic beams (EB). With the greater attention paid to environ mentel protection in recent years ,radiation curing has developed rapidly.

  2. Accelerated Cure Project for Multiple Sclerosis (United States)

    ... main content Accelerating research toward a cure for multiple sclerosis Home Contact Us Search form Search Connect Volunteer ... is to accelerate efforts toward a cure for multiple sclerosis by rapidly advancing research that determines its causes ...

  3. Stress Free Temperature Testing and Calculations on Out-of-Autoclave Composites (United States)

    Cox, Sarah B.; Tate, LeNetra C.; Danley, Susan E.; Sampson, Jeffrey W.; Taylor, Brian J.; Sutter, James K.; Miller, Sandi G.


    Future launch vehicles will require the incorporation of large composite parts that will make up primary and secondary components of the vehicle. NASA has explored the feasibility of manufacturing these large components using Out-of-Autoclave impregnated carbon fiber composite systems through many composites development projects. Most recently, the Composites for Exploration Project has been looking at the development of a 10 meter diameter fairing structure, similar in size to what will be required for a heavy launch vehicle. The development of new material systems requires the investigation of the material properties and the stress in the parts. Residual stress is an important factor to incorporate when modeling the stresses that a part is undergoing. Testing was performed to verify the stress free temperature with two-ply asymmetric panels. A comparison was done between three newly developed out of autoclave IM7/Bismaleimide (BMI) systems. This paper presents the testing results and the analysis performed to determine the stress free temperature of the materials

  4. Treatment of Clinical Solid Waste Using a Steam Autoclave as a Possible Alternative Technology to Incineration

    Directory of Open Access Journals (Sweden)

    Mohd Omar Ab Kadir


    Full Text Available A steam autoclave was used to sterilize bacteria in clinical solid waste in order to determine an alternative to incineration technology in clinical solid waste management. The influence of contact time (0, 5, 15, 30 and 60 min and temperature (111 °C, 121 °C and 131 °C at automated saturated steam pressure was investigated. Results showed that with increasing contact time and temperature, the number of surviving bacteria decreased. The optimum experimental conditions as measured by degree of inactivation of bacteria were 121 °C for 15 minutes (min for Gram negative bacteria, 121 °C and 131 °C for 60 and 30 min for Gram positive bacteria, respectively. The re-growth of bacteria in sterilized waste was also evaluated in the present study. It was found that bacterial re-growth started two days after the inactivation. The present study recommends that the steam autoclave cannot be considered as an alternative technology to incineration in clinical solid waste management.

  5. Use of clinoptilolite for the immobilization of heavy metal ions and preparation of autoclaved building composites

    Energy Technology Data Exchange (ETDEWEB)

    Mozgawa, W., E-mail: [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. Mickiewicza 30, 30-059 Krakow (Poland); Krol, M.; Pichor, W. [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, al. Mickiewicza 30, 30-059 Krakow (Poland)


    The work presents the results of application of natural clinoptilolite for immobilization of heavy metal cations (Ag{sup +}, Pb{sup 2+}, Cd{sup 2+} and Cr{sup 3+}) from aqueous solutions and uses zeolite to prepare autoclaved building composites. Sorption has been conducted on sodium form of natural clinoptilolite originated from Poland. Clinoptilolite (sodium form containing heavy metal cations) has been applied to obtain new building materials which have good physical properties. Samples produced by autoclaving process showed relatively low bulk density (about 1.35 g/cm{sup 3}). The compressive strength depended on the amount of CaO in the initial mixture. Its maximum value was about 40 MPa. The influence of heavy metal cations on the compressive strength values was insignificant (except for the Cr{sup 3+} ions). However, all the cations modified the microstructure and the ordered state of C-S-H phase. Efficiency of Ag{sup +}, Cd{sup 2+} and Pb{sup 2+} ions immobilization on the mineral matrix was shown. In the work, results of IR spectroscopy, atomic absorption spectroscopy (AAS) studies, X-ray diffraction analysis, SEM observations and technological investigations are presented.

  6. Immunohistochemical diagnosis of Alport's syndrome in paraffin-embedded renal sections: antigen retrieval with autoclave heating. (United States)

    Naito, Ichiro; Ninomiya, Yoshifumi; Nomura, Shinsuke


    Alport's syndrome (AS) is a hereditary renal disease caused by mutations in the genes encoding collagen type IV. Immunohistochemical analysis of the alpha chains of collagen type IV has been found to be useful for the diagnosis of this disease. The monoclonal antibodies (mAbs) generated by us recognize alpha 1(IV) through alpha 6(IV) chains of collagen type IV on fresh-frozen sections but not on paraffin-embedded sections. Antigen retrieval by autoclave heating has been found to restore the epitopes recognized by the mAbs; however the heating conditions had not been well established. In this study, the heating conditions were carefully examined using renal sections obtained from AS and non-AS patients. The heating was performed in an autoclave, at 105 degrees -127 degrees C for 6-8 min. During the heating, the sections were immersed in 0.2 N HCl solution (pH 0.9). Then, the mAbs were applied for 30 min, and the bound mAbs were detected using the LSAB kit. The optimal temperature for the antigen retrieval varied among specimens, and was dependent on the type of basement membrane examined. Thus, it was considered that heating at two or three different temperatures could be helpful for the precise diagnosis of AS. Adopting the antigen retrieval method could extend the possibility of immunohistochemical diagnosis of AS to cases without using fresh-frozen sections.

  7. Evaluation of an autoclave resistant anatomic nose model for the testing of nasal swabs. (United States)

    Bartolitius, Lennart; Frickmann, Hagen; Warnke, Philipp; Ottl, Peter; Podbielski, Andreas


    A nose model that allows for the comparison of different modes of sample acquisition as well as of nasal swab systems concerning their suitability to detect defined quantities of intranasal microorganisms, and further for training procedures of medical staff, was evaluated. Based on an imprint of a human nose, a model made of a silicone elastomer was formed. Autoclave stability was assessed. Using an inoculation suspension containing Staphylococcus aureus and Staphylococcus epidermidis, the model was compared with standardized glass plate inoculations. Effects of inoculation time, mode of sampling, and sample storage time were assessed. The model was stable to 20 autoclaving cycles. There were no differences regarding the optimum coverage from the nose and from glass plates. Optimum sampling time was 1 h after inoculation. Storage time after sampling was of minor relevance for the recovery. Rotating the swab around its own axis while circling the nasal cavity resulted in best sampling results. The suitability of the assessed nose model for the comparison of sampling strategies and systems was confirmed. Without disadvantages in comparison with sampling from standardized glass plates, the model allows for the assessment of a correct sampling technique due to its anatomically correct shape.

  8. Stress Free Temperature Testing and Residual Stress Calculations on Out-of-Autoclave Composites (United States)

    Cox, Sarah; Tate, LaNetra C.; Danley, Susan; Sampson, Jeff; Taylor, Brian; Miller, Sandi


    Future launch vehicles will require the incorporation large composite parts that will make up primary and secondary components of the vehicle. NASA has explored the feasibility of manufacturing these large components using Out-of-Autoclave impregnated carbon fiber composite systems through many composites development projects. Most recently, the Composites for Exploration Project has been looking at the development of a 10 meter diameter fairing structure, similar in size to what will be required for a heavy launch vehicle. The development of new material systems requires the investigation of the material properties and the stress in the parts. Residual stress is an important factor to incorporate when modeling the stresses that a part is undergoing. Testing was performed to verify the stress free temperature with two-ply asymmetric panels. A comparison was done between three newly developed out of autoclave IM7 /Bismalieimide (BMI) systems. This paper presents the testing results and the analysis performed to determine the residual stress of the materials.

  9. Treatment of clinical solid waste using a steam autoclave as a possible alternative technology to incineration. (United States)

    Hossain, Md Sohrab; Balakrishnan, Venugopal; Rahman, Nik Norulaini Nik Ab; Sarker, Md Zaidul Islam; Kadir, Mohd Omar Ab


    A steam autoclave was used to sterilize bacteria in clinical solid waste in order to determine an alternative to incineration technology in clinical solid waste management. The influence of contact time (0, 5, 15, 30 and 60 min) and temperature (111 °C, 121 °C and 131 °C) at automated saturated steam pressure was investigated. Results showed that with increasing contact time and temperature, the number of surviving bacteria decreased. The optimum experimental conditions as measured by degree of inactivation of bacteria were 121 °C for 15 minutes (min) for Gram negative bacteria, 121 °C and 131 °C for 60 and 30 min for Gram positive bacteria, respectively. The re-growth of bacteria in sterilized waste was also evaluated in the present study. It was found that bacterial re-growth started two days after the inactivation. The present study recommends that the steam autoclave cannot be considered as an alternative technology to incineration in clinical solid waste management.

  10. [A project to improve the validity rate for nursing staff operating single door autoclave sterilizers]. (United States)

    Chen, Chun-Hung; Li, Cheng-Chang; Chou, Chuan-Yu; Chen, Shu-Hwa


    This project was designed to improve the low validity rate for nurses responsible to operate single door autoclave sterilizers in the operating room. By investigating the current status, we found that the nursing staff validity rate of cognition on the autoclave sterilizer was 85%, and the practice operating check validity rate was only 80%. Such was due to a lack of in-service education. Problems with operation included: 1. Unsafe behaviors - not following standard procedure, lacking relevant operating knowledge and absence of a check form; 2. Unsafe environment - the conveying steam piping was typically not covered and lacked operation marks. Recommended improvement measures included: 1. holding in-service education; 2. generating an operation procedure flow chart; 3. implementing obstacle eliminating procedures; 4. covering piping to prevent fire and burns; 5. performing regular checks to ensure all procedures are followed. Following intervention, nursing staff cognition rose from 85% to 100%, while the operation validity rate rose from 80% to 100%. These changes ensure a safer operating room environment, and helps facilities move toward a zero accident rate in the healthcare environment.

  11. Curcumin complexation with cyclodextrins by the autoclave process: Method development and characterization of complex formation. (United States)

    Hagbani, Turki Al; Nazzal, Sami


    One approach to enhance curcumin (CUR) aqueous solubility is to use cyclodextrins (CDs) to form inclusion complexes where CUR is encapsulated as a guest molecule within the internal cavity of the water-soluble CD. Several methods have been reported for the complexation of CUR with CDs. Limited information, however, is available on the use of the autoclave process (AU) in complex formation. The aims of this work were therefore to (1) investigate and evaluate the AU cycle as a complex formation method to enhance CUR solubility; (2) compare the efficacy of the AU process with the freeze-drying (FD) and evaporation (EV) processes in complex formation; and (3) confirm CUR stability by characterizing CUR:CD complexes by NMR, Raman spectroscopy, DSC, and XRD. Significant differences were found in the saturation solubility of CUR from its complexes with CD when prepared by the three complexation methods. The AU yielded a complex with expected chemical and physical fingerprints for a CUR:CD inclusion complex that maintained the chemical integrity and stability of CUR and provided the highest solubility of CUR in water. Physical and chemical characterizations of the AU complexes confirmed the encapsulated of CUR inside the CD cavity and the transformation of the crystalline CUR:CD inclusion complex to an amorphous form. It was concluded that the autoclave process with its short processing time could be used as an alternate and efficient methods for drug:CD complexation.

  12. The effect of autoclaving on soluble protein composition and trypsin inhibitor activity of cracked soybeans

    Directory of Open Access Journals (Sweden)

    Stanojević Slađana P.


    Full Text Available The effects of autoclaving conditions (heating for 5, 10 and 15 minutes at 0.5 bars over pressure and oil-extracting temperatures (40°C, 60°C on protein content, composition, and inhibitor activity of cracked soybeans were investigated. The results obtained indicated that oil-extracting method and heat treatment had significant influence on soluble protein content and composition. Raw soybean samples defatted at lower temperature had better solubility (535.42±2.10 mg/g than those obtained by the Soxhlet procedure (345.53±2.80. The same results were obtained for nitrogen solubility index. Autoclaving combined with two oil-extraction methods decreased protein solubility to 180.32±1.50 -245.41±1.41 mg/g, while the dominant component of heat treated flours was 11S fraction. High content of glycinin fraction (44.59-41.10% implies the possible use of treated samples in food industry. Residual activity of treated samples was 43.40-84.26%. Kunitz inhibitor (KTI was responsible for residual inhibitor activity.

  13. Numeric model of the normative consumption of heat for the colour homogenisation of wood in pressure autoclaves (United States)

    Dzurenda, Ladislav


    This paper presents a numeric model of the normative consumption of heat for the colour homogenisation of unfrozen wood using saturated steam in pressure autoclaves, in the form of a technically feasible standard. For more effective determination of the objectively necessary consumption of heat for steaming non-frozen wood in a steam autoclave, a program was prepared in EXCEL in the form of a numeric table. Based on the technical and technological data on machinery, the range of colour homogenised wood and the colour-homogenisation regime, the program provides information about normative - the consumption of heat per 1 mł - of colour homogenised wood as well as about the consumption of heat for individual items of the thermal balance off the process of colour homogenisation in a pressure autoclave.

  14. Validation of the efficacy of a solar-thermal powered autoclave system for off-grid medical instrument wet sterilization. (United States)

    Kaseman, Tremayne; Boubour, Jean; Schuler, Douglas A


    This work describes the efficacy of a solar-thermal powered autoclave used for the wet sterilization of medical instruments in off-grid settings where electrical power is not readily available. Twenty-seven trials of the solar-thermal powered system were run using an unmodified non-electric autoclave loaded with a simulated bundle of medical instruments and biological test agents. Results showed that in 100% of the trials the autoclave achieved temperatures in excess of 121°C for 30 minutes, indicator tape displayed visible reactions to steam sterilization, and biological tests showed that microbial agents had been eliminated, in compliance with the Centers for Disease Control and Prevention requirements for efficacious wet sterilization.

  15. 压力蒸汽灭菌器的性能验证%The Performance Validation of Autoclave

    Institute of Scientific and Technical Information of China (English)

    吕恒源; 杨海军


    Autoclave is a common device of validation. By the performance validation of autoclave, we can confirm that the autoclave can reaches the performance requirements of equipment within the prescribed time, temperature and pressure conditions, reagents can be effective sterilization.%压力蒸汽灭菌器是一种常见的消毒灭菌装置。通过开展灭菌效果验证可确认压力蒸汽灭菌器是否能在规定的时间、温度和压力条件下达到设备性能指标要求,试剂是否能被有效灭菌。

  16. The Design of Autoclave Controlling System%发泡建材蒸压釜控制系统设计

    Institute of Scientific and Technical Information of China (English)



    发泡建材蒸压釜属大型压力容器,主要介绍了符合蒸压釜相关安全性能规定的控制器设计方法,以及规模蒸压釜群的能源管理系统的设计方法,从而可以实现设备与能源的最优利用.%The autoclave is a kind of large pressure vessel. The design method of autoclave controller, used in the production of aerated concrete, was mainly introduced, as well as the energy management system for scaled autoclave group by which the optimal utilization of facilities and energy could be realized.

  17. Treatment of infectious waste: development and testing of an add-on set for used gravity displacement autoclaves. (United States)

    Stolze, René; Kühling, Jan-Gerd


    The safe management of potentially infectious healthcare waste is gaining increasing worldwide importance. In developing countries, simple incinerators are used for the treatment of this type of waste stream. However, as these incinerators produce high emissions and represent the main generators of dioxin and furans in these countries, alternative and cost-effective solutions are needed. As steam treatment systems do not produce persistent organic pollutants, the use of existing (older) medical autoclaves could represent a solution for the treatment of infectious waste. ETLog Health EnviroTech & Logistics, the German-based consulting and engineering company carried out the first research into whether gravity air displacement autoclaves can be used for the safe decontamination of infectious waste. The research showed that it is not possible to decontaminate waste using this type of autoclave. A subsequent research and development phase might, however, make it possible to develop a new process cycle. Tests carried out on the basis of international standards and norms showed that by applying this process cycle and using an add-on set, it is possible to treat healthcare waste using the existing stock of older medical autoclaves. The process cycle and the add-on set developed were tested under existing conditions in Hanoi, Vietnam using the treatment cycle developed for a 13-year-old autoclave. All the parameters for infectious waste decontamination were reached. As modified autoclaves prevent the emission of toxic substances, this approach presents an interim solution, which avoids the impacts on human health and the environment caused by the incineration of healthcare waste.

  18. Techniques for internal water curing of concrete

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Pietro, Lura


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

  19. The effects of composition, diameter and post-curing methods on the flexural properties of fiber posts.

    Directory of Open Access Journals (Sweden)

    Nadia Ereifej.


    Full Text Available Objective: This study evaluated the influence of fiber composition, diameter and post-curing treatments performed at relining on flexural strength and modulus of fiber-posts. Materials and methods: Sixty posts of Reforpost® Glass Fiber [GF] and Reforpost® Carbon Fiber [CF] (Angelus, Londrina, PR, Brazil with diameters of 1.0mm and 1.4mm were used. Each group was further subdivided into three subgroups (n=5 according to treatment received: dry-stored control group (C, oven-cured (Ov or autoclaved (Ac. A universal testing machine measured flexural strength and modulus of all specimens. Results: Post composition and post-curing treatments had no significant effects on flexural properties of specimens while post diameter had significant effects (p<0.05. The highest flexural strength and modulus (MPa (1331±95.8 and 21532±1550, respectively were obtained with Ov/GF/1.1, while lowest values (890±79.4 and 10675±952, respectively were for Ac/GF/1.5. Conclusions: 1.1mm diameter posts had better mechanical properties than 1.5mm thick posts. Neither post composition nor post-curing procedures affected the mechanical properties of relined posts.

  20. From HCV To HBV Cure. (United States)

    Schinazi, Raymond F; Asselah, Tarik


    Approximately 170 million people are chronically infected with HCV and 350 million are chronically infected with HBV worldwide. It is estimated that more than one million patients die from complications related to chronic viral hepatitis, mainly HCC which is one of the most frequent cancers in many countries, especially Africa, the Middle East and Asia. HCV drug development has been impressive, and this revolution led to several direct-acting antiviral agents achieving an HCV cure after only 6-12 weeks. This progress could theorically lead to HCV global elimination making HCV and its consequences a rarity. HBV research and development programs can learn from the HCV experience, to achieve an HBV functional or sterilizing cure. This review will summarize key steps which have been realized for an HCV cure, and discuss the next steps to achieve for an HCV elimination. And also, how this HCV revolution has inspired scientists and clinicians to achieve the same for HBV.

  1. Freud's psychoanalysis: a moral cure. (United States)

    Eriksson, Johan


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

  2. Process test on five-autoclave linkage operation for autoclaved fly ash brick%蒸压粉煤灰砖“五釜联动操作”的工艺试验

    Institute of Scientific and Technical Information of China (English)



    On the basis of the possibility analysis of five-autoclave linkage operation for autoclaving fly ash brick combine of the Tianyie building material company autoclaved fly ash brick production line, the paper describes the improvement on supply steam equipment of autoclave, so as to achieve energy conservation.%结合天业建材公司蒸压粉煤灰砖的生产实践,在对蒸压粉煤灰砖五釜联动操作的可行性分析、研究的基础上,提出了对蒸压釜供汽部分的设备改造方案和蒸压粉煤灰砖五釜联动操作的工艺试验方案,指出砖瓦企业实现节能减排、低碳发展必须抓好关键设备的技术改造、技术创新。

  3. Composite cure monitoring with Bragg grating sensors (United States)

    Slattery, Kerry T.; Corona-Bittick, Kelli; Dorr, Donald J.


    Residual stress is induced in fiber composite materials during the cure process because the thermal expansion coefficient of the fiber is generally much lower than that of the polymer matrix. The two materials are 'locked' together at the cure temperature. Then, as they cool, the matrix attempts to contract more than the fiber leading to tension in the matrix and compression in the fiber. This can lead to the formation of microcracks parallel to the fibers in thick composite piles or yarns. The magnitude of residual stress can be reduced by modifying the cure cycle; however, optimizing the cure cycle requires a complete understanding of the state of cure throughout the composite. This is a complex problem -- especially in thick composites. Pilot studies have been performed placing Bragg gratin sensors in glass fabric preforms and monitoring the response of the grating during resin infusion and cure. The typical response shows the initial thermal expansion of the Bragg grating, a rapid contraction of the grating as the resin gels, slower contraction during cure, and thermal contraction at the composite thermal expansion coefficient during cool down. This data is then sued with micromechanical models of the fiber/matrix interaction during cure to establish material parameters for cure simulation. Once verified, these cure simulation methods will be used to optimize tooling design and cure cycles in composite components.

  4. MODIFIKASI PATI GARUT (Marantha arundinacea DENGAN PERLAKUAN SIKLUS PEMANASAN SUHU TINGGI-PENDINGINAN ( AUTOCLAVING-COOLING CYCLING UNTUK MENGHASILKAN PATI RESISTEN TIPE III [Arrowroot (Marantha arundinacea Starch Modification Through Autoclaving-Cooling Cycling Treatment to Produce Resistant Starch Type III

    Directory of Open Access Journals (Sweden)



    Full Text Available The objectives of this research were to modify arrowroot starch to produce resistant starch type III by autoclaving-cooling cycling and to characterize the modified arrowroot starches according to their chemical properties. The research consisted of three steps : arrowroot extraction, starch modification, and chemical characterization. The extraction of arrowroot produced 10.78% starch. Starch modification by autoclaving-cooling cycle(s was run in 6 different treatments with the aim of observing optimal yield of resistant starch. Resistant starch (RS was produced through 1, 3, 5 cycle(s of autoclaving-cooling treatment with different gelatinization periods (15 and 30 minutes autoclaving for each cycle. Properties analyzed were starch digestibility, fat content, protein content, resistant starch content, and dietary fiber content. Native starch and commercial RS type III (Novelose 330 were also analyzed as a comparison. Based on the starch digestibility, modified starch from 5 cycles, 15 minutes gelatinization period had the lowest digestibility while modified starch from 3 cycles, 15 minutes gelatinization period had no significant difference with commercial RS type III. Those two modified starches, native starch, and Novelose 330 were chosen for further chemical analysis. The fat content and protein content of the four samples were below 1% (db. Low fat and protein content were required to optimize the RS yield. The modification treatment increased the dietary fiber content. The RS content of native starch, Novelose 330, modified starch 3 cycles, 15 minutes gelatinization period, and modified starch 5 cycles, 15 minutes gelatinization period were 2.12% (db, 20.80% (db, 10.91% (db, and 12.15% (db, respectively. It means that repeating autoclaving-cooling cycling could increase RS yield up to 6 times.

  5. Preparation of Slowly Digestible Starch by Citric Acid-hydrolysis with Autoclaving

    Directory of Open Access Journals (Sweden)

    Hansong Yu


    Full Text Available Aim of study is to produce Slowly Digestible Starch (SDS by a combination of citric acid-hydrolysis and autoclaving from raw corn starch. The effects of citric acid concentration, acid hydrolysis time, temperature and refrigeration and retro gradation time on the formation of SDS were investigated. The optimal process conditions optimized by Box-Benhnken’s central composite design and response surface analysis was as follows: concentration of citric acid is 0.08 M, acid hydrolyzed at 116°C for 14.5 min, and then stored at 0°C for 72 h. Under these optimal conditions, the content of SDS peaked at 19.38%.

  6. Note: CO₂-mineral dissolution experiments using a rocking autoclave and a novel titanium reaction cell. (United States)

    Purser, Gemma; Rochelle, Christopher A; Wallis, Humphrey C; Rosenqvist, Jörgen; Kilpatrick, Andrew D; Yardley, Bruce W D


    A novel titanium reaction cell has been constructed for the study of water-rock-CO2 reactions. The reaction cell has been used within a direct-sampling rocking autoclave and offers certain advantages over traditional "flexible gold/titanium cell" approaches. The main advantage is robustness, as flexible cells are prone to rupture on depressurisation during gas-rich experiments. The reaction cell was tested in experiments during an inter-laboratory comparison study, in which mineral kinetic data were determined. The cell performed well during experiments up to 130 °C and 300 bars pressure. The data obtained were similar to those of other laboratories participating in the study, and also to previously published data.

  7. Spring-back simulation of flat symmetrical laminates with angled plies manufactured through autoclave processing (United States)

    Nasir, M. N. M.; Aminanda, Y.; Mezeix, L.; Seman, M. A.; Rivai, A.; Ali, K. M.


    This paper presents a non-linear finite element analysis (FEA) method to predict the spring-back deformation for composite structures manufactured using autoclave processing. It is a progression from previous accompanying study on flat unidirectional samples and the aim is to observe spring-back warpage on laminates consisting of angled (±45°) plies compared to unidirectional (0°) laminate. Three samples for each of the symmetrical laminates with angled plies [45/0]S and [45/-45]S are manufactured and the warpage form is observed. FEA model that was utilized in the previous study, along with the physical mechanisms of spring-back such as the first ply stretching and tool-part interaction mechanisms, are maintained with only changes in material orientation for the part and the tool-part interface components. Upon comparison, the data shows that the spring-back form for symmetrical laminate becomes more complex to predict.

  8. Comparative Evaluation of Dimensional Accuracy of Elastomeric Impression Materials when Treated with Autoclave, Microwave, and Chemical Disinfection


    Kamble, Suresh S.; Khandeparker, Rakshit Vijay; Somasundaram, P; Raghav, Shweta; Babaji, Rashmi P; Varghese, T Joju


    Background: Impression materials during impression procedure often get infected with various infectious diseases. Hence, disinfection of impression materials with various disinfectants is advised to protect the dental team. Disinfection can alter the dimensional accuracy of impression materials. The present study was aimed to evaluate the dimensional accuracy of elastomeric impression materials when treated with different disinfectants; autoclave, chemical, and microwave method. Materials and...

  9. 蒸压釜釜盖开裂失效分析%Failure Analysis on Cracking of Autoclave Cover

    Institute of Scientific and Technical Information of China (English)

    潘安霞; 师红旗; 丁毅; 马立群


    采用宏微观组织分析、化学成分分析、SEM断口形貌分析、EDS腐蚀产物化学成分分析等手段,分析了321不锈钢釜盖开裂的原因.结果表明,该釜盖的开裂属于氯化物应力腐蚀开裂,蒸压釜的工作介质和工作压力共同导致了釜盖的开裂,并提出了相应的改进措施.%The cracking of autoclave cover was analyzed by morphology and microstnicture analysis, SEM micro-morphology of fracture surface, EDS corrosion products analysis. The results show that the cracking of autoclave cover is attributed to stress corrosion cracking. Working stress and working fluid of the autoclave cover lead to the cracking of the autoclave cover jointly. Finally, the relative protection countermeasures are proposed.

  10. The effect of autoclaving on the physical and biological properties of dicalcium phosphate dihydrate bioceramics: brushite vs. monetite. (United States)

    Tamimi, Faleh; Le Nihouannen, Damien; Eimar, Hazem; Sheikh, Zeeshan; Komarova, Svetlana; Barralet, Jake


    Dicalcium phosphate dihydrate (brushite) is an osteoconductive biomaterial with great potential as a bioresorbable cement for bone regeneration. Preset brushite cement can be dehydrated into dicalcium phosphate anhydrous (monetite) bioceramics by autoclaving. This heat treatment results in changes in the physical characteristics of the material, improving in vivo bioresorption. This property is a great advantage in bone regeneration; however, it is not known how autoclaving brushite preset cement might improve its capacity to regenerate bone. This study was designed to compare brushite bioceramics with monetite bioceramics in terms of physical characteristics in vitro, and in vivo performance upon bone implantation. In this study we observed that monetite bioceramics prepared by autoclaving preset brushite cements had higher porosity, interconnected porosity and specific surface area than their brushite precursors. In vitro cell culture experiments revealed that bone marrow cells expressed higher levels of osteogenic genes Runx2, Opn, and Alp when the cells were cultured on monetite ceramics rather than on brushite ones. In vivo experiments revealed that monetite bioceramics resorbed faster than brushite ones and were more infiltrated with newly formed bone. In summary, autoclaving preset brushite cements results in a material with improved properties for bone regeneration procedures.

  11. Cure-A-Phobia感

    Institute of Scientific and Technical Information of China (English)




  12. Report: Factors affecting the content of potentially toxic elements in the biodegradable fraction of autoclaved household waste. (United States)

    Papadimitriou, Efstathios K; Barton, John R


    A total of 3.4 tonnes of household waste (HW) that had a controlled composition were autoclaved in the presence of saturated steam for 1 h at the nominal temperature levels of 130, 160 and 200 degrees C. The levels of Cd, Cr, Cu, Pb, Hg, Ni, and Zn were examined in samples of the fibrous, predominantly-biodegradable fraction (floc) derived from the autoclaved HW, aqueous extracts from floc, and the condensate from steam that was released from the reactor. This data was used to study the impact of the overall levels of potential toxic elements (PTEs) in HW feed and autoclaving process parameters on the levels of PTEs in floc. No consistent correlation was found to exist between the levels of PTEs in HW feed and those in the produced floc. This was primarily attributed in the inherent variability of PTEs in waste materials. Autoclaving temperature, pressure and mixing were all found to affect the mobilization and removal of PTEs from HW and their presence in floc. Temperature/pressure appeared to increase PTE removal through the condensate path, although that removal had only a negligible impact on the contents of PTEs in floc. Autoclaving temperature correlated positively, although not significantly at a 95% confidence level, with the levels of Pb and Zn in floc. On the other hand, it correlated negatively with the Hg content in floc. Increasing temperature/pressure also increased the water extraction of PTEs from floc, with the exception of Cr. However, in the context of producing high quality compost, the extraction rates were too low to bring about a substantial decrease of PTEs in floc.

  13. Comparative analysis of the effect of autoclaving and 10% formalin storage on extracted teeth: A microleakage evaluation

    Directory of Open Access Journals (Sweden)

    Attam Kanika


    Full Text Available Aim: This study compares the effect of formalin and autoclaving the tooth samples by evaluating microleakage in-vitro . Materials and Methods: Forty-five extracted human permanent incisor teeth were taken and randomly divided into three groups (with different methods of storage and disinfection with 15 teeth each: Group 1: Control-extracted teeth in this group were stored in normal saline, Group 2: the extracted teeth in this group were stored in 10 % formalin for two weeks and Group 3: the extracted teeth were Autoclaved at 121°C, at 15 psi pressure for 40 minutes. In all the groups after the specified storage period, class V cavities were prepared on the labial surface and restoration was performed with Z100 restorative. Finished and polished samples were subjected to 500 cycles of thermocycling. All specimens were immersed in methylene blue for 24 hours. After sectioning, the margins of restora-tion were evaluated for dye leakage at 10 X magnification, using an optical microscope. Data were subjected to nonparametric Kruskal Wallis one way analysis of variance. Inter-group comparisons were performed using the Mann Whitney test ( P < 0.05. Results: The authors found that the microleakage in the formalin group was considerably lower than that in the control group. The autoclave group showed slightly higher mean microleakage, but the difference was not statistically significant. Conclusion: Both autoclaving and formalin storage affect, to a varying degree, the microleakage values in vitro . The results in the autoclaving group matched those of the control group more closely, with only a slight difference.

  14. Dimensional stability ofautoclave sterilised addition cured impressions and trays. (United States)

    Deb, S; Etemad-Shahidi, S; Millar, B J


    The aim of this study was to investigate the dimensional accuracy of impressions following sterilisation by autoclaving. Dental impressions (75) were of a dentoform containing 6 reference points. The impressions were split into 5 groups of 15, each group used a different impression technique. Groups were divided into 3 subgroups with 5 impressions as control, 5 for disinfection by Perform-ID and 5 being autoclaved. Measurements were made using a travelling light microscope. A minimal significant dimensional difference (0.01impression method. No significant dimensional differences were observed for all other groups (P>0.05). The trays and materials tested were suitable for the autoclave sterilisation.

  15. Interfacial Properties of Electron Beam Cured Composites

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, C.C.


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

  16. Microwave Cure of Phenol-Formaldehyde Adhesive


    高谷, 政広; 田平, 英敏; 岡本, 忠


    [Synopsis] Phenol-formaldehyde resin has been used as a versatile material for adhesives and coatings of a wide range of adherends because of its excellent performance in water- resistance, strength against abrasion, and so on. However, it has a drawback of slow rate of cure and relevant emission of formaldehyde gas after bonding. We studied the curing performance under irradiation of microwave for the purpose of looking for a way of accelerating the cure rate of phenol formaldehyde resin. Th...

  17. Electron Beam Curing of Advanced Composites

    Institute of Scientific and Technical Information of China (English)


    The fundamental concept of electron beam method and the application in cure of composites are elaborated in this paper. The components of electron beam curing system are introduced. The mechanisms of interaction between electron beam and polymer matrix composites are presented. Recent studies reported including work of authors themselves on electron beam curing of composites are also discussed. Moreover, the authors believe that it is necessary to do the basic research about understanding how electron beam affects cured network and the mechanical/physical properties of the composites, for establishing a quantitative or semi-quantitative formulation.

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

    Directory of Open Access Journals (Sweden)

    Priyanka Verma


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

  19. Prevention is better than cure

    CERN Multimedia

    Anaïs Schaeffer


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

  20. Hepatitis C, stigma and cure. (United States)

    Marinho, Rui Tato; Barreira, David Pires


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

  1. Curing Mechanism of Condensed Polynuclear Aromatic Resin and Thermal Stability of Cured Resin

    Institute of Scientific and Technical Information of China (English)

    Li Shibin; Sun Qiqian; Wang Yuwei; Wu Mingbo; Zhang Zailong


    In order to improve the thermal stability of condensed polynuclear aromatic (COPNA) resin synthesized from vacuum residue, 1,4-benzenedimethanol was added to cure COPNA resin. The curing mechanism was investigated by pro-ton nuclear magnetic resonance spectrometry, solid carbon-13 nuclear magnetic resonance spectrometry and Fourier trans-form infrared spectroscopy. Microstructures of the uncured and the cured COPNA resins were studied by scanning electron microscopy and X-ray diffractometry. The thermal stability of COPNA resins before and after curing was tested by thermo-gravimetric analysis. The element composition of the cured COPNA resin heated at different temperatures was analyzed by an element analyzer. The results showed that the uncured COPNA resin reacted with the cross-linking agent during the cur-ing process, and the curing mechanism was conifrmed to be the electrophilic substitution reaction. Compared with the un-cured COPNA resin, the cured COPNA resin had a smooth surface, well-ordered and streamlined sheet structure with more crystalline solids, better molecular arrangement and orientation. The weight loss process of the uncured and cured COPNA resins was divided into three stages. Carbon residue of the cured COPNA resin was 41.65%at 600℃, which was much higher than 25.02%of the uncured COPNA resin, which indicated that the cured COPNA resin had higher thermal stability.

  2. 7 CFR 29.6010 - Cured. (United States)


    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Cured. 29.6010 Section 29.6010 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6010 Cured. Tobacco dried of its sap by either natural or...

  3. Dental resin cure monitoring by inherent fluorescence (United States)

    Li, Qun; Zhou, Jack X.; Li, Qingxiong; Wang, Sean X.


    It is demonstrated that the inherent fluorescence of a dental composite resin can be utilized to monitor the curing status, i.e. degree of conversion of the resin. The method does not require any sample preparation and is potentially very fast for real time cure monitoring. The method is verified by Raman spectroscopy analysis.

  4. Direct Synthesis of Fe3C-Functionalized Graphene by High Temperature Autoclave Pyrolysis for Oxygen Reduction

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei


    We present a novel approach to direct fabrication of few-layer graphene sheets with encapsulated Fe3C nanoparticles from pyrolysis of volatile non-graphitic precursors without any substrate. This one-step autoclave approach is facile and potentially scalable for production. Tested as an electroca......We present a novel approach to direct fabrication of few-layer graphene sheets with encapsulated Fe3C nanoparticles from pyrolysis of volatile non-graphitic precursors without any substrate. This one-step autoclave approach is facile and potentially scalable for production. Tested...... as an electrocatalyst, the graphene-based composite exhibited excellent catalytic activity towards the oxygen reduction reaction in alkaline solution with an onset potential of ca. 1.05 V (vs. the reversible hydrogen electrode) and a half-wave potential of 0.83 V, which is comparable to the commercial Pt/C catalyst....

  5. Comparative study and histomorphometric analysis of bone allografts lyophilized and sterilized by autoclaving, gamma irradiation and ethylene oxide in rats

    Directory of Open Access Journals (Sweden)

    Otavio Machado de Almeida


    Full Text Available PURPOSE: To compare three sterilization methods (autoclave, gamma irradiation and ethylene oxide over non demineralized lyophilized bone allografts. METHODS: Bone allografts were implanted on paravertebral muscles of 21 rats. After 30 days animals were sacrificed and grafts underwent comparative analysis regarding histomorphometric and macroscopic parameters. RESULTS: Allografts that underwent the three sterilization methods presents similar weight gain, cortical thickness similar to control group, and less fibrosis than the control group. Grafts that underwent sterilization in autoclave presented less presence of multinucleated giant cells, although not statistically significant. There was also no statistically significant difference regarding mineralization on the three groups. CONCLUSION: The three sterilization methods cause similar effects on bone allografts regarding macroscopic and histomorphometric parameters.

  6. [Technological process of cell disruption for extracting astaxanthin from Phaffia rhodozyma by acid method under autoclave conditions]. (United States)

    Lu, Baoju; Xiao, Anfeng; Lil, Lijun; Ni, Hui; Cai, Huinong; Su, Wenjin


    Phaffia rhodozyma is one of the organisms for production of astaxanthin, and the key process for extracting intracellular astaxanthin is cell disruption. In this work, cell disruption for extracting astaxanthin from Phaffia rhodozyma was studied with autoclave method at low acid concentration. The optimum disrupting conditions were: autoclave pressure 0.1 MPa, 121 degrees C; hydrochloric acid concentration 0.5 mol/L; liquid to material ratio (V/W) 30 mL/g dry cell weight and disruption time 2 min. Under the optimum conditions, medium scale experiment showed that astaxanthin and total carotenoids recovery from Phaffia rhodozyma were (84.8 +/- 3.2)% and (93.3 +/- 2)%, respectively. This new method can lead to no poisonous residues and get high extraction yield, which have good prospects to be put into industrial production.

  7. 9 CFR 319.103 - Cured beef tongue. (United States)


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

  8. Structure-Processing-Property Relationships at the Fiber-Matrix Interface in Electron-Beam Cured Composite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C.J.


    The objective of this project was to characterize the properties of the resin and the fiber- resin interface in electron beam cured materials by evaluating several structural and processing parameters. The Oak Ridge National Laboratory (ORNL) has recently determined that the interlaminar shear strength properties of electron beam cured composites were 19-28% lower than for autoclave cured composites. Low interlaminar shear strength is widely acknowledged as the key barrier to the successfid acceptance and implementation of electron beam cured composites in industry. In this project we found that simple resin modification and process improvements are unlikely to substantially improve the interlaminar shear strength properties of electron beam cured composites. However, sizings and coatings were shown to improve these properties and there appears to be significant potential for further improvement. In this work we determined that the application of epoxy-based, electron beam compatible sizings or coatings onto surface- treated, unsized carbon fibers improved the composite interlaminar shear strength by as much as 55% compared to composites fabricated from surface-treated, unsized carbon fibers and 11 YO compared to composites made from surface-treated, GP sized carbon fibers. This work has identified many promising pathways for increasing the interlaminar shear strength of electron beam cured composites. As a result of these promising developments we have recently submitted a U.S. Department of Energy-Energy Research (DOE-ER) sponsored Laboratory Technical Research-Cooperative Research and Development Agreement (LTR- CRADA) proposal entitled, "Interracial Properties of Electron Beam Cured Composites", to continue this work. If funded, ORNL will lead a 3-year, $2.6 million effort involving eight industrial partners, NASA-Langley, and the U.S. Air Force. The principal objective of this CRADA is to significantly improve the interracial properties of carbon

  9. Curing agent for polyepoxides and epoxy resins and composites cured therewith. [preventing carbon fiber release (United States)

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


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

  10. Synthesis of hollow ZnO microspheres by an integrated autoclave and pyrolysis process. (United States)

    Duan, Jinxia; Huang, Xintang; Wang, Enke; Ai, Hanhua


    Hollow zinc oxide microspheres have been synthesized from a micro ZnBr2·2H2O precursor obtained by an autoclave process in bromoform steam at 220 °C /2.5 MPa. Field-emission scanning electron microscropy (FE-SEM) and transmission electron microscopy (TEM) show that the products are about 1.0 µm single crystal spherical particles with hollow interiors, partly open surfaces and walls self-assembled by ZnO nanoparticles. X-ray diffraction (XRD) analysis shows that the as-prepared ZnO hollow spheres are of a hexagonal phase structure. A possible formation mechanism is suggested on the basis of the shape evolution of ZnO nanostructures observed by SEM and TEM. The room-temperature photoluminescence (PL) spectrum shows UV emission around 386 nm and weak green emission peaks indicating that there are few defects in the single crystal grains of the ZnO microspheres.

  11. Pressure-accelerated azide-alkyne cycloaddition: micro capillary versus autoclave reactor performance. (United States)

    Borukhova, Svetlana; Seeger, Andreas D; Noël, Timothy; Wang, Qi; Busch, Markus; Hessel, Volker


    Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard conditions are well established. Herein, we apply novel-process-window (NPWs) principles, such as intensification of intrinsic kinetics of a reaction using high temperature, pressure, and concentration, on azide-alkyne cycloaddition towards synthesis of Rufinamide precursor. We applied three main activation methods (i.e., uncatalyzed batch, uncatalyzed flow, and catalyzed flow) on uncatalyzed and catalyzed azide-alkyne cycloaddition. We compare the performance of two reactors, a specialized autoclave batch reactor for high-pressure operation up to 1800 bar and a capillary flow reactor (up to 400 bar). A differentiated and comprehensive picture is given for the two reactors and the three methods of activation. Reaction speedup and consequent increases in space-time yields is achieved, while the process window for favorable operation to selectively produce Rufinamide precursor in good yields is widened. The best conditions thus determined are applied to several azide-alkyne cycloadditions to widen the scope of the presented methodology.

  12. Development and calibration of a load sensing cervical distractor capable of withstanding autoclave sterilization. (United States)

    Demetropoulos, C K; Truumees, E; Herkowitz, H N; Yang, K H


    In surgery of the cervical spine, a Caspar pin distractor is often used to apply a tensile load to the spine in order to open up the disc space. This is often done in order to place a graft or other interbody fusion device in the spine. Ideally a tight interference fit is achieved. If the spine is over distracted, allowing for a large graft, there is an increased risk of subsidence into the endplate. If there is too little distraction, there is an increased risk of graft dislodgement or pseudoarthrosis. Generally, graft height is selected from preoperative measurements and observed distraction without knowing the intraoperative compressive load. This device was designed to give the surgeon an assessment of this applied load. Instrumentation of the device involved the application of strain gauges and the selection of materials that would survive standard autoclave sterilization. The device was calibrated, sterilized and once again calibrated to demonstrate its suitability for surgical use. Results demonstrate excellent linearity in the calibration, and no difference was detected in the pre- and post-sterilization calibrations.

  13. CO2 sequestration by carbonation of steelmaking slags in an autoclave reactor. (United States)

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Chu, Hsiao-Wen; Wang, Chu-Fang; Chiang, Pen-Chi


    Carbon dioxide (CO(2)) sequestration experiments using the accelerated carbonation of three types of steelmaking slags, i.e., ultra-fine (UF) slag, fly-ash (FA) slag, and blended hydraulic slag cement (BHC), were performed in an autoclave reactor. The effects of reaction time, liquid-to-solid ratio (L/S), temperature, CO(2) pressure, and initial pH on CO(2) sequestration were evaluated. Two different CO(2) pressures were chosen: the normal condition (700 psig) and the supercritical condition (1300 psig). The carbonation conversion was determined quantitatively by using thermo-gravimetric analysis (TGA). The major factors that affected the conversion were reaction time (5 min to 12h) and temperature (40-160°C). The BHC was found to have the highest carbonation conversion of approximately 68%, corresponding to a capacity of 0.283 kg CO(2)/kg BHC, in 12h at 700 psig and 160°C. In addition, the carbonation products were confirmed to be mainly in CaCO(3), which was determined by using scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) to analyze samples before and after carbonation. Furthermore, reaction kinetics were expressed with a surface coverage model, and the carbon footprint of the developed technology in this investigation was calculated by a life cycle assessment (LCA).

  14. Preparation of New Cementitious System using Fly Ash and Dehydrated Autoclaved Aerated Concrete

    Institute of Scientific and Technical Information of China (English)

    SHUI Zhonghe; LU Jianxin; TIAN Sufang; SHEN Peiliang; DING Sha


    We experimentally studied the interaction between pozzolanic material (fly ash) and dehydrated autoclaved aerated concrete (DAAC). The DAAC powder was obtained by grinding aerated concrete waste to particles finer than 75μm and was then heated to temperatures up to 900℃. New cementitious material was prepared by proportioning fly ash and DAAC, named as AF. X-ray diffraction (XRD) was employed to identify the crystalline phases of DAAC before and after rehydration. The hydration process of AF was analyzed by the heat of hydration and non-evaporable water content (Wn). The experimental results show that the highest reactivity of DAAC can be obtained by calcining the powder at 700℃and the dehydrated products are mainlyβ-C2S and CaO. The cumulative heat of hydration and Wn was found to be strongly dependent on the replacement level of fly ash, increasing the replacement level of fly ash lowered them in AF. The strength contribution rates on pozzolanic effect of fly ash in AF are always negative, showing a contrary tendency of that of cement-fly ash system.

  15. Nonlinear Modeling of Autoclaved Aerated Concrete Masonry Wall Strengthened using Ferrocement Sandwich Structure

    KAUST Repository

    M., Abdel-Mooty


    Autoclaved Aerated Concrete (AAC) block are used mainly as non-load-bearing walls that provide heat insulation. This results in considerable saving in cooling energy particularly in hot desert environment with large variation of daily and seasonal temperatures. However, due to the relatively low strength there use load bearing walls is limited to single storey and low-rise construction. A system to enhance the strength of the AAC masonry wall in resisting both inplane vertical and combined vertical and lateral loads using ferrocement technology is proposed in this research. The proposed system significantly enhances the load carrying capacity and stiffness of the AAC wall without affecting its insulation characteristics. Ferrocement is made of cement mortar reinforced with closely spaced wire mesh. Full scale wall specimens with height of 2100mm and width of 1820mm were tested with different configuration of ferrocement. A finite elementmodel is developed and verified against the experimentalwork. The results of the finite element model correlates well with the experimental results.

  16. The Hydrothermal Autoclave Synthesis of the Nanopowders of the Refractory ZrO2 and HfO2 Oxides

    Directory of Open Access Journals (Sweden)

    N.F. Karpovich


    Full Text Available The nanopowders of the transition metal ZrO2 and HfO2 oxides were obtained by the hydrothermal autoclave synthesis. The nanoparticles possess a rounded shape and a size range of 40 to 80 nm (ZrO2, of 10 to 40 nm (HfO2. X-ray diffraction analysis and electron microscopy show that the structure of the nanoparticles is monoclinic.

  17. Improving the purity of GaN grown by the ammonothermal method with in-autoclave gas-phase acidic mineralizer synthesis (United States)

    Tomida, D.; Chichibu, S. F.; Kagamitani, Y.; Bao, Q.; Hazu, K.; Simura, R.; Sugiyama, K.; Yokoyama, C.; Ishiguro, T.; Fukuda, T.


    In-autoclave synthesis of a gas-phase acidic mineralizer was investigated for high-purity GaN growth by the ammonothermal (AT) method. To reduce oxygen contamination of GaN from highly hygroscopic NH4Cl powder, purified NH3 and HCl gases were introduced sequentially fed into a Pt-lined autoclave to synthesize NH4Cl within the autoclave. The autoclave was pre-charged with GaN seed wafers and polycrystalline precursors, and carefully dehydrated under dynamic vacuum. Because of the decrease in oxygen concentration, the lattice parameter approached the intrinsic value. The Ga-polar layers exhibit a near-band-edge emission peak at room temperature.

  18. Induction of cellular and humoral responses by autoclaved and heat-killed antigen of Leishmania donovani in experimental visceral leishmaniasis. (United States)

    Nagill, Rajeev; Mahajan, Raman; Sharma, Meenakshi; Kaur, Sukhbir


    The potential of autoclaved and heat-killed antigen of Leishmania donovani to induce cell-mediated and humoral response has been evaluated in the present study. The vaccines were delivered thrice subcutaneously at an interval of 2 weeks. Two weeks after second booster, BALB/c mice were challenged with 10(7) stationary phase promastigotes of L. donovani. Significant protection was achieved in immunized mice against L. donovani challenge with 69% to 76% and 59% to 64% reduction in parasite load in the liver and spleen respectively. Immunization induced significantly higher level of delayed type hypersensitivity (DTH) response in mice immunized with heat-killed antigen followed by autoclaved antigen. The immune response was assessed by quantifying Leishmania-specific antibodies and cytokine production. The antibody response was predominantly of IgG type with increased IgG2a production and lesser amount of IgM. The immunization preferentially stimulates the production of IFN-gamma and IL-2 in splenocytes which suggests a Th1 type response with a concomitant down-regulation of IL-10 and IL-4. These results indicate a potential for the heat-killed and autoclaved antigen as a vaccine which could trigger cell-mediated immune response.

  19. Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces. (United States)

    Nagai, Masahiro; Takakuda, Kazuo


    The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.

  20. Curing efficiency of modern LED units. (United States)

    Rencz, Adam; Hickel, Reinhard; Ilie, Nicoleta


    Recent reports claim that modern light-emitting diode (LED) curing units improve curing efficiency by increasing the units' irradiance. In this context also, short polymerisation times up to 5 s are proposed. The aim of this study was to examine whether there are differences in the curing efficiency of modern LED curing units by assessing their effect on two different composite materials and by varying the irradiation time. A nano- and a micro-hybrid resin-based composite (RBC) were polymerised for 5, 10 and 20 s with three commercial and a Prototype LED unit (Elipar™ S10). Cylindrical specimens (6 mm in depth, 4 mm in diameter) were prepared in three increments, each 2-mm thick, and were consecutively cured. Degree of cure was measured for 20 min in real time at the bottom of the samples, starting with the photoinitiation. The micro-mechanical properties (modulus of elasticity, E and Vickers hardness, HV) were measured as a function of depth, in 100-μm steps, on the above described samples stored in distilled water for 24 h at 37°C. Data were analysed with multivariate ANOVA followed by Tukey's test, t test and partial eta-squared statistics. In descending order of the strength of their effect, the type of RBC, depth, polymerisation time and curing unit were significant factors affecting the micro-mechanical parameters (p surface, a minimum of 20 s of irradiation is necessary for an adequate polymerisation 2 mm beyond the surface.

  1. One-step microwave foaming and curing (United States)

    Gagliani, J.; Lee, R.; Sorathia, U. A. K.; Wilcoxson, A. L.


    Process that combines microwave foaming and curing of polyimide precursors in single step produces fire-resistant foam slabs of much larger volume than has previously been possible. By adding selected conductive fillers to powder precursors and by using high-power microwave oven, foam slabs with dimensions in excess of 61 by 61 by 7.6 cm are made. Typical foaming and curing and curing time is 35 minutes in microwave oven with additional 1 to 2 hour postcure in conventional oven.

  2. Estabelecimento de ciclo de cura de pré-impregnados aeronáuticos Establishment of cure cycle of aeronautic prepregs

    Directory of Open Access Journals (Sweden)

    Michelle L. Costa


    Full Text Available Os compósitos poliméricos podem ser produzidos via moldagem em autoclave, onde as condições de processamento podem ser otimizadas a partir do conhecimento físico-químico da matriz polimérica. A evolução da cinética da reação de cura ocorre simultaneamente com as modificações no comportamento reológico do sistema polimérico, sendo comum denominar o fenômeno de comportamento reo-cinético. O presente trabalho tem como objetivo conhecer os parâmetros de cura, cinéticos e reológicos, de três diferentes sistemas de pré-impregnados de resina epóxi (cura a 177 °C, conhecidos como F161, F584 e 8552, hoje usados na indústria aeronáutica brasileira. Este estudo foi realizado com o auxílio das técnicas de DSC e reologia, utilizando-se análises dinâmicas e isotérmicas. Com isso, foi possível estabelecer a ordem de reação e a cinética de cura dos sistemas estudados. Neste estudo, foram utilizados como modelos matemáticos o de ordem n e o autocatalítico com ordem total de aproximadamente 2. A temperatura de gel foi de ~100 °C, e o tempo de gel correspondente foi de 135 segundos. A partir do conhecimento da cinética de cura e dos parâmetros reológicos dos sistemas de pré-impregnados foi possível estabelecer um ciclo de cura destinado à consolidação das peças aeronáuticas via moldagem em autoclave.Autoclave molding produces polymer composites, where the processing conditions can be optimized with physicochemical knowledge of the polymeric matrix. The cure reaction evolves simultaneously with changes in rheology, which is normally refered to as rheo-kinetic behavior. With the knowledge of the appropriate cure cycle one can identify the steps in which pressure should be applied and when to raise the temperature. This paper is aimed at investigating the cure, kinetics and rheological parameters of three prepreg epoxy systems, namely F161, F584 and 8552, which are currently used in the Brazilian aeronautic industry

  3. Acceleration of curing of resin composite at the bottom surface using slow-start curing methods. (United States)

    Yoshikawa, Takako; Morigami, Makoto; Sadr, Alireza; Tagami, Junji


    The aim of this study was to evaluate the effect of two slow-start curing methods on acceleration of the curing of resin composite specimens at the bottom surface. The light-cured resin composite was polymerized using one of three curing techniques: (1) 600 mW/cm(2) for 60 s, (2) 270 mW/cm(2) for 10 s+0-s interval+600 mW/cm(2) for 50 s, and (3) 270 mW/cm(2) for 10 s+5-s interval+600 mW/cm(2) for 50 s. After light curing, Knoop hardness number was measured at the top and bottom surfaces of the resin specimens. The slow-start curing method with the 5-s interval caused greater acceleration of curing of the resin composite at the bottom surface of the specimens than the slow-start curing method with the 0-s interval. The light-cured resin composite, which had increased contrast ratios during polymerization, showed acceleration of curing at the bottom surface.

  4. [Mineral water as a cure]. (United States)

    Nocco, Priska Binz


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

  5. Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

    KAUST Repository

    Chubar, Natalia


    The sorption of Mn(II) by viable and inactivated cells of Shewanella putrefaciens, a non-pathogenic, facultative anaerobic, gram-negative bacterium characterised as a Mn(IV) and Fe(III) reducer, was studied under aerobic conditions, as a function of pH, bacterial density and metal loading. During a short contact time (3-24h), the adsorptive behaviour of live and dead bacteria toward Mn(II) was sufficiently similar, an observation that was reflected in the studies on adsorption kinetics at various metal loadings, effects of pH, bacteria density, isotherms and drifting of pH during adsorption. Continuing the experiment for an additional 2-30days demonstrated that the Mn(II) sorption by suspensions of viable and autoclaved cells differed significantly from one another. The sorption to dead cells was characterised by a rapid equilibration and was described by an isotherm. In contrast, the sorption (uptake) to live bacteria exhibited a complex time-dependent uptake. This uptake began as adsorption and ion exchange processes followed by bioprecipitation, and it was accompanied by the formation of polymeric sugars (EPS) and the release of dissolved organic substances. FTIR, EXAFS/XANES and XPS demonstrated that manganese(II) phosphate was the main precipitate formed in 125ml batches, which is the first evidence of the ability of microbes to synthesise manganese phosphates. XPS and XANES spectra did not detect Mn(II) oxidation. Although the release of protein-like compounds by the viable bacteria increased in the presence of Mn2+ (and, by contrast, the release of carbohydrates did not change), electrochemical analyses did not indicate any aqueous complexation of Mn(II) by the organic ligands. © 2012 Elsevier Ltd.

  6. Light-cured resin for post patterns. (United States)

    Waldmeier, M D; Grasso, J E


    A method of using light-cured acrylic resin as an alternative to the use of chemically-cured acrylic resins with elastomeric impressions for direct post patterns is presented. The GC Unifast LC acrylic resin is a powder/liquid type resin cured by exposure to visible light. The polymerization process has four stages before final curing: slurry, stringy, dough-like (plastic), and rubber-like (elastic). Advantages over current direct and indirect procedures include ease of manipulation of the material and no change in laboratory handling procedures. While in the dough-like state, the material can be contoured. In the rubber-like state, it is flexible to disengage from minor undercut areas.

  7. Fast Curing of Composite Wood Products

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Arthur J. Ragauskas


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


    Directory of Open Access Journals (Sweden)

    Johannes Steinhaus


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

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

    Directory of Open Access Journals (Sweden)


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

  10. 蒸压膨胀珍珠岩保温板的研制及性能分析%Research on the preparation and properties of autoclaved insulation board made by expanded perlite

    Institute of Scientific and Technical Information of China (English)

    张宪圆; 林克辉; 谢红波; 杨军


    Expanded perlite insulation board was successfully prepared by autoclave curing method,which two kinds of expanded perlite with different packing densities were used as light-weight aggregate respectively,and Portland cement or self-made binder was used as cementing material. Hydrophobic treatment was also applied. The results indicate that the compressive and flexural strengths of insulation board made in this way are much higher than the requirement in national standard GB/T 10303-2001 "Expanded Perlite Thermal Insulation"; volume water absorption of EP insulation board is reduced significantly when the emulsion of silicone hydrophobic agent is used.%采用2种堆积密度不同的膨胀珍珠岩作轻骨料,以水泥和自制胶结料作为胶凝材料,通过蒸压养护方式制备成保温板,并进行了憎水处理.结果表明,采用该工艺制备的保温板其抗压及抗折强度优于GB/T10303-2001《膨胀珍珠岩绝热制品》标准要求;有机硅憎水剂乳液可显著降低保温板的体积吸水率.

  11. High Power UV LED Industrial Curing Systems

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. Cure fraction estimation from the mixture cure models for grouped survival data. (United States)

    Yu, Binbing; Tiwari, Ram C; Cronin, Kathleen A; Feuer, Eric J


    Mixture cure models are usually used to model failure time data with long-term survivors. These models have been applied to grouped survival data. The models provide simultaneous estimates of the proportion of the patients cured from disease and the distribution of the survival times for uncured patients (latency distribution). However, a crucial issue with mixture cure models is the identifiability of the cure fraction and parameters of kernel distribution. Cure fraction estimates can be quite sensitive to the choice of latency distributions and length of follow-up time. In this paper, sensitivity of parameter estimates under semi-parametric model and several most commonly used parametric models, namely lognormal, loglogistic, Weibull and generalized Gamma distributions, is explored. The cure fraction estimates from the model with generalized Gamma distribution is found to be quite robust. A simulation study was carried out to examine the effect of follow-up time and latency distribution specification on cure fraction estimation. The cure models with generalized Gamma latency distribution are applied to the population-based survival data for several cancer sites from the Surveillance, Epidemiology and End Results (SEER) Program. Several cautions on the general use of cure model are advised.

  13. Comparative study on compressive strength of Self cured SCC and Normally cured SCC

    Directory of Open Access Journals (Sweden)

    Ms. Akanksha A. Patil


    Full Text Available Curing is the process of maintaining proper moisture content particularly within 28 days to promote optimum cement hydration immediately after placement. Self-compacting concrete is made up of admixture i.e. superplasticizer. In recent years, self-compacting concrete (SCC has gained wide use for placement in congested reinforced concrete structures with difficult casting conditions. Also various curing methods are adopted in the construction industry especially for vertical structures, inaccessible areas s.a. high rise buildings, water scarce areas etc. In such structures conventional curing is not practically possible in most of the cases. But we need efficient curing which improves the strength and durability of concrete. In the present work, comparison of compressive strength of normally cured SCC and SCC cured with self curing material i.e. wax based, white pigmented, membrane forming concrete curing compound has been done. This study is investigating that weather the use of self curing compound is economical or not in remote areas of water without compromising with the compressive strength of concrete.

  14. Fiber-Reinforced Epoxy Composites and Methods of Making Same Without the Use of Oven or Autoclave (United States)

    Barnell, Thomas J. (Inventor); Rauscher, Michael D. (Inventor); Stienecker, Rick D. (Inventor); Nickerson, David M. (Inventor); Tong, Tat H. (Inventor)


    Method embodiments for producing a fiber-reinforced epoxy composite comprise providing a mold defining a shape for a composite, applying a fiber reinforcement over the mold, covering the mold and fiber reinforcement thereon in a vacuum enclosure, performing a vacuum on the vacuum enclosure to produce a pressure gradient, insulating at least a portion of the vacuum enclosure with thermal insulation, infusing the fiber reinforcement with a reactive mixture of uncured epoxy resin and curing agent under vacuum conditions, wherein the reactive mixture of uncured epoxy resin and curing agent generates exothermic heat, and producing the fiber-reinforced epoxy composite having a glass transition temperature of at least about C. by curing the fiber reinforcement infused with the reactive mixture of uncured epoxy resin and curing agent by utilizing the exothermically generated heat, wherein the curing is conducted inside the thermally insulated vacuum enclosure without utilization of an external heat source or an external radiation source.

  15. Direct synthesis of Fe3 C-functionalized graphene by high temperature autoclave pyrolysis for oxygen reduction. (United States)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei; Huang, Yunjie; Cleemann, Lars N; Xing, Wei; Bjerrum, Niels J; Li, Qingfeng


    We present a novel approach to direct fabrication of few-layer graphene sheets with encapsulated Fe3 C nanoparticles from pyrolysis of volatile non-graphitic precursors without any substrate. This one-step autoclave approach is facile and potentially scalable for production. Tested as an electrocatalyst, the graphene-based composite exhibited excellent catalytic activity towards the oxygen reduction reaction in alkaline solution with an onset potential of ca. 1.05 V (vs. the reversible hydrogen electrode) and a half-wave potential of 0.83 V, which is comparable to the commercial Pt/C catalyst.

  16. Autoclaved aerated concrete masonry with external insulation. Features of moisture conditions during the initial period of operation (rus

    Directory of Open Access Journals (Sweden)

    Kuptaraeva P.D.


    Full Text Available Building designs at the moment of commissioning include the initial (building and technological moisture. Thermal insulation systems influence on the yield of the initial moisture from the structures. However, there are no specific design requirements about determining initial moisture content in insulation systems.In this article the features of the initial period of operation on an example of aerated concrete are defined: the results of field surveys and calculations are shown and compared. On the basis of this comparison basic advice on the accounting features of the initial period of operation of autoclaved aerated concrete structures with external insulation are given.

  17. Measurement on Hydrate Products Crystallinity Degrees of Autoclaved Silicate Products%蒸压硅酸盐制品水化产物的结晶度分析

    Institute of Scientific and Technical Information of China (English)

    柯昌君; 王淑英; 王浩; 袁兵


    利用烧失量和酸溶法测定不同固体废物蒸压样品的结合水量和溶出差,研究固体废物蒸压样品中水化产物量、结晶度与其强度的关系.结果表明,粉煤灰、废玻璃、废混凝土蒸压样品的结晶度较低,钢渣蒸压样品的结晶度较高.蒸压样品的溶出差、结合水量和结晶度与水化产物种类有关.蒸压样品的结晶度可间接表达结晶良好的水化产物占总水化产物量的多少,并可用来确定不同蒸压制品的合理养护制度,指导蒸压制品的工艺优化.蒸压样品的结晶度存在合理范围.%The relationships of solid waste autoclaved samples compressive strength and their crystal-Unity degrees, hydrate amounts were studied with dissolved amount difference and bound water a-mount measured with loss on ignition and acid digestion method. The results showed that the crystal-linity degrees of autoclaved samples, such as fly ash, waste glass and waste concrete are in a low level except that the crystallinity degree of autoclaved steel slag sample is higher. The dissolved amount difference, bound water amount and crystallinity degree of the autoclaved samples were related to their hydrate types. The crystallinity degrees of autoclaved samples could be indirectly represented as the ratios of well-crystallized hydrate amounts to total hydrate amounts in the autoclaved samples, and used to determine the autoclaved schedule and guide the technology optimization for autoclaved products. There is a reasonable crystallinity degree range for the compressive strength of autoclaved samples.


    Institute of Scientific and Technical Information of China (English)

    Jian-wen Bao; Yang Li; Xiang-bao Chen; Feng-mei Li


    Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250°C.

  19. Assessment of Curing Efficiency and Effect of Moist Curing on Performance of Fly Ash Concrete

    Institute of Scientific and Technical Information of China (English)

    LI Meili; QIAN Jueshi; WANG Lixia; XU Shanshan; JIA Xingwen; FAN Yunyan


    This study was conducted to evaluate the sensitivity of compressive strength,water permeability and electrical resistance of near-surface layer concrete with different fly ash contents to curing conditions. It is shown that the sensitivity to curing condition and fly ash content descends in the following order: difference between internal and surface resistivity (ρ)at 28 days, water permeability and compressive strength; both of longer duration of moist curing and use of fly ash in concrete enhanced the water penetration resistance. It is indicated that the resistivity difference p at 28 days can reflect accurately the curing history of fly ash concrete regardless of mix proportions; and use of fly ash in concrete requires longer moist curing duration.

  20. Strength development, hydration reaction and pore structure of autoclaved slag cement with added silica fume

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Y. [China Building Materials Academy, Beijing (China); Siemer, D.D. [LITCO, Idaho Falls, ID (United States); Scheetz, B.E. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.


    Under continuous hydrothermal treatment the strength of portland cement paste decreases with curing time and the pore structure coarsens. It was found in this study that the compressive strength of slag cement paste containing 67.5 wt.% ggbfs also decreases with time after 24 hour hydrothermal processing, but with a small addition of silica fume to the slag cement, the cement strength increases and the pore structure densifies when processed under comparable conditions. Based on observations XRD and SEM, these changes are attributed to: (1) changes in the hydration reactions and products by highly reactive silica fume, such that amorphous products dominate and the strength reducing phase {alpha}-C{sub 2}SH does not form; (2) slower hydration of slag, partially caused by the decreased pH of the pore solution, favors the formation of a dense pore structure; and (3) the space filling properties of the micro particles of silica fume.

  1. Diclofenac sodium injection sterilized by autoclave and the occurrence of cyclic reaction producing a small amount of impurity. (United States)

    Roy, J; Islam, M; Khan, A H; Das, S C; Akhteruzzaman, M; Deb, A K; Alam, A H


    A known impurity is formed in the production of a parenteral dosage form of diclofenac sodium if terminally sterilized by autoclave. This impurity has been detected as 1-(2,6-dichlorophenyl) indolin-2qone, which is also an intermediate from which diclofenac sodium is generally synthesized. It is only the condition of the autoclave method (i.e., 123 +/- 2 degrees C) that enforces the intramolecular cyclic reaction of diclofenac sodium forming the indolinone derivative and sodium hydroxide. The formation of this impurity has been found to depend on the initial pH of the formulation. The reaction follows first-order kinetics, and the energy of activation is 5.34 kcal/mol. The other excipients in the formulation do not have a role in this reaction. The concentration of the impurity in the resultant product in the ampule goes beyond the limit of the raw materials in the pharmacopoeias. It is thus preferable to use an alternative sterilization method; that is, an aseptic filtration method in which the formation of this impurity can be avoided.

  2. [The effect of autoclave sterilization on the surface properties of orthodontic brackets after fitting in the mouth]. (United States)

    Rerhrhaye, W; Ouaki, B; Zaoui, F; Aalloula, E


    Repeated sterilizations of the orthodontic bands, after fitting in mouth, are likely to involve modifications of their surface properties. Through this study we have tried to observe the effect of sterilization by autoclave on the surface of the orthodontic bands, as well as the contribution of the use of ultrasound in the chain of sterilization. The sample was composed of 30 orthodontic bands divided into 5 groups: a group of new bands (witnesses) and 4 groups having undergone respectively 1 cycle, 3 cycles, 5 cycles and 7 cycles of autoclave sterilization according to the World Health Organization recommendations. For half of each group bands, ultrasonic cleaning has not been provided. The scanning electron microscopy with the elementary microanalysis by X-rays was used for the investigation of surface. At the exam, new bands showed surface irregularities probably due to manufacturing procedures. And the bands, without ultrasonic cleaning, showed the presence of contamination and discolourations. Moreover, there were no modifications on the surface of the bands cleaned by ultrasounds before sterilization. The presence of surface irregularities associated with deposits observed on the bands surface, may be the site of bio corrosion by contributing bio film accumulation. The stay duration of the orthodontic bands in mouth, during orthodontic treatment, is important. So the effect of sterilization on the surface of the orthodontic bands must encourage other scientific research to determine the long term effects of sterilization which remains an essential process in our daily practice.

  3. Solubility study of nickel ferrite in boric acid using a flow-through autoclave system under high temperature and high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Choi, Ke Chon; Ha, Yeong Keong [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    The solubility of nickel ferrite in an aqueous solution of boric acid was studied by varying the pH at the temperatures ranging from 25 .deg. C to 320 .deg. C. A flow-through autoclave system was specially designed and fabricated to measure the solubility of Fe in hydrothermal solutions under high temperature and pressure. The performance of this flow-through system was directly compared with the conventional static state technique using a batch-type autoclave system. The stability of fluid velocity for the flow-through autoclave system was verified prior to the solubility measurement. The influence of chemical additives, such as boric acid and H2, on the solubility of nickel ferrite was also evaluated.

  4. Validation of Autoclave Protocols for Successful Decontamination of Category A Medical Waste Generated from Care of Patients with Serious Communicable Diseases. (United States)

    Garibaldi, Brian T; Reimers, Mallory; Ernst, Neysa; Bova, Gregory; Nowakowski, Elaine; Bukowski, James; Ellis, Brandon C; Smith, Chris; Sauer, Lauren; Dionne, Kim; Carroll, Karen C; Maragakis, Lisa L; Parrish, Nicole M


    In response to the Ebola outbreak in 2014, many hospitals designated specific areas to care for patients with Ebola and other highly infectious diseases. The safe handling of category A infectious substances is a unique challenge in this environment. One solution is on-site waste treatment with a steam sterilizer or autoclave. The Johns Hopkins Hospital (JHH) installed two pass-through autoclaves in its biocontainment unit (BCU). The JHH BCU and The Johns Hopkins biosafety level 3 (BSL-3) clinical microbiology laboratory designed and validated waste-handling protocols with simulated patient trash to ensure adequate sterilization. The results of the validation process revealed that autoclave factory default settings are potentially ineffective for certain types of medical waste and highlighted the critical role of waste packaging in successful sterilization. The lessons learned from the JHH validation process can inform the design of waste management protocols to ensure effective treatment of highly infectious medical waste.

  5. Curing mechanism of flexible aqueous polymeric coatings. (United States)

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


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

  6. Prevent and cure disuse bone loss (United States)

    Jee, Webster S. S.


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

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

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


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

  8. Production process and equipment selection of autoclaved brick%一种蒸压砖生产工艺流程及设备选型

    Institute of Scientific and Technical Information of China (English)



    The paper describes how to reduce the added proportion of calcium carbide slurry, improve the auto⁃claved brick quality, and reduce production costs of autoclaved brick by optimizing the production process and equipment selection to eliminate the mud clumping of calcium carbide slurry in autoclaved calcium carbide sludge brick.%通过优化生产工艺流程及设备选型消除电石泥蒸压砖中的电石泥结团,降低电石泥原料添加比例和提高蒸压砖质量,降低蒸压砖生产成本。

  9. An energy-dispersive X-ray analysis and SEM study of debris remaining on endodontic instruments after ultrasonic cleaning and autoclave sterilization. (United States)

    Parirokh, Masoud; Asgary, Saeed; Eghbal, Mohammad Jafar


    This study was carried out to investigate metallic and non-metallic debris remaining on endodontic files after ultrasonic cleaning and autoclave processing. Forty-eight unused rotary and hand endodontic files, including eight different brands, were tested. Instruments were cleaned with ultrasound, autoclaved and before and after each step were observed by scanning electron microscopy (SEM). Adherent debris was analysed by energy-dispersive X-ray analysis (EDXA). All of the instruments before ultrasound cleaning were contaminated with metallic and non-metallic debris. Although most non-metallic debris was removed by ultrasonic cleaning, most of the metallic debris remained even after the final step of sterilization.

  10. Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure. (United States)

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


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

  11. Creep measurements on curing epoxy systems

    DEFF Research Database (Denmark)

    Kammer, Charlotte; Szabo, Peter


    The chemical curing of a stoichiometric mixture of the diglycidyl ether of bisphenol A and a 1,3-bis-(aminomethyl)-cyclohexane is studied.Creep experiments are combined with measurements in a Differential Scanning Calorimeter (DSC) to determine the change in bulk viscosity due to network formation....

  12. Mechanical characterization and modeling of curing thermosets

    NARCIS (Netherlands)

    Van 't Hof, C.


    Chemical shrinkage and simultaneous build-up of mechanical properties in curing thermosets leads to the build-up of residual stresses and strains. Depending on the constraints these may cause interface failure, dimensional inaccuracy or failure in the thermoset or its surrounding structure. The pre


    Institute of Scientific and Technical Information of China (English)


    This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent.The technology of microwave curing E44 epoxy resins is investigated,the mechanical properties of cured epoxy resin samples in different contents of curing agent by microwave and thermal curing methods are measured respectively, and then some experimental results for which are obtained.At last, this paper analyses why microwave curing can improve mechanical property of epoxy resin.

  14. Thermal and Cure Kinetics of Epoxy Molding Compounds Cured with Thermal Latency Accelerators

    Directory of Open Access Journals (Sweden)

    Chean-Cheng Su


    Full Text Available The cure kinetics and mechanisms of a biphenyl type epoxy molding compounds (EMCs with thermal latency organophosphine accelerators were studied using differential scanning calorimetry (DSC. Although the use of triphenylphosphine-1,4-benzoquinone (TPP-BQ and triphenylphosphine (TPP catalysts in biphenyl type EMCs exhibited autocatalytic mechanisms, thermal latency was higher in the TPP-BQ catalyst in EMCs than in the TPP catalyst in EMCs. Analyses of thermal characteristics indicated that TPP-BQ is inactive at low temperatures. At high temperatures, however, TPP-BQ increases the curing rate of EMC in dynamic and isothermal curing experiments. The reaction of EMCs with the TPP-BQ latent catalyst also had a higher temperature sensitivity compared to the reaction of EMCs with TPP catalyst. In resin transfer molding, EMCs containing the TPP-BQ thermal latency accelerator are least active at a low temperature. Consequently, EMCs have a low melt viscosity before gelation, and the resins and filler are evenly mixed in the kneading process. Additionally, flowability is increased before the EMCs form a network structure in the molding process. The proposed kinetic model adequately describes curing behavior in EMCs cured with two different organophosphine catalysts up to the rubber state in the progress of curing.

  15. Bond strength of a light-cured and two auto-cured glass ionomer liners. (United States)

    Holtan, J R; Nystrom, G P; Olin, P S; Rudney, J; Douglas, W H


    Ninety-nine extracted human molar teeth were used in this study comparing the shear bond strengths on dentine of one light-cured and two auto-cured polyalkenoate (glass ionomer) cements. Bond strength can be influenced by differences in tooth structure. A balanced-incomplete block design (Hull and Nie, 1981) was used to reduce variation attributable to such differences. Cements were applied to paired dentine surfaces in combinations such that 66 tooth sides were treated with each material. A light-cured dentinal adhesive and composite resin restorative material were then placed and shear bond strength testing was conducted exactly 24 h after the completion of each specimen. Mean forces (MPa) for the three materials were compared using an appropriate analysis of variance model (balanced-incomplete-blocks) The shear bond strengths (MPa) of the light-cured liner (Espe, Seefeld/Oberbay, FRG) was 4.71 +/- 1.16. Vitrabond showed the greatest variance of all three materials tested, however this material's average bond strength was greater than the maximum achieved for the other materials. Student-Newman-Keuls comparison of means showed that all cements differed significantly from each other (alpha = 0.05). It is concluded that the light-cured glass ionomer liner exhibited significantly better shear bond strength performance than the two auto-cured glass ionomers tested.

  16. [Dimensional accuracy of microwave-cured denture base resin]. (United States)

    Uchida, K; Okamoto, F; Ogata, K; Sato, T


    Recently, microwave-cured denture base resin was developed, and the resin solved the problem of internal porosity which had been generated by curing the conventional denture base resins with microwave irradiation. In this study, the dimensional accuracy of microwave-cured denture base resin was compared with that of other denture base resins, such as pour-type resin, heat-cured resin and heat-shock resin. From the experiment, the following results were obtained. 1. Dimensional accuracy of microwave-cured denture base resin was better than that of heat-cured resin and heat-shock resin, and was similar to that of pour-type resin. 2. Dimensional accuracy of microwave-cured denture base resin by slow cooling method and rapid cooling method was almost the same. Those findings suggest that microwave-cured denture base resin is valuable in clinic.

  17. Effect of curing on clinical retention. A 7-year evaluation

    DEFF Research Database (Denmark)

    van Dijken, Jan WV; Pallesen, Ulla

    Objective: To evaluate in a prospective evaluation the retention of Class V compomer and hybrid resin composite restorations placed with a 1-step self etch system and cured with continuous, soft-start and pulse-delay curing. Methods: 139 Class V restorations were placed and cured at random in 60...... subjects with a compomer (Dyract AP;68) or resin composite (Tetric Ceram:67) and cured for 40s with continuous, soft-start and pulse-delay modes. The restorations were evaluated with slightly modified USPHS criteria yearly during 7 years. Results: Of 135 restorations evaluated at 7 years, 29 were lost, 17...... compomer (25%) and 12 Tetric Ceram (18%). The cumulative loss rates for the compomer and resin composite restorations cured with the three curing modes were. continuous cure: 26.1%/18.2%, soft-start: 22.7%/19.0%, pulse delay: 26.1%/16.7%. No statistical difference were seen between the curing modes...

  18. Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots (United States)

    ... Drinking Peroxide as 'Natural' Cure Leads to Dangerous Blood Clots ... 9, 2017 (HealthDay News) -- Ingesting high-concentration hydrogen peroxide as a "natural cure" or cleansing agent may ...

  19. Mössbauer study of oxide films of Fe-, Sn-, Cr- doped zirconium alloys during corrosion in autoclave (United States)

    Filippov, V. P.; Bateev, A. B.; Lauer, Yu. A.


    Mössbauer investigations were used to compare iron atom states in oxide films of binary Zr-Fe, ternary Zr-Fe-Cu and quaternary Zr-Fe-Cr-Sn alloys. Oxide films are received in an autoclave at a temperature of 350-360 °C and at pressure of 16.8 MPa. The corrosion process decomposes the intermetallic precipitates in alloys and forms metallic iron with inclusions of chromium atoms α-Fe(Cr), α-Fe(Cu), α-Fe 2O3 and Fe 3O4 compounds. Some iron ions are formed in divalent and in trivalent paramagnetic states. The additional doping influences on corrosion kinetics and concentration of iron compounds and phases formed in oxide films. It was shown the correlation between concentration of iron in different chemical states and corrosion resistance of alloys.

  20. Determination of metal concentrations in certified plastic reference materials after small-size autoclave and microwave-assisted digestion followed with inductively coupled plasma optical emission spectrometry (United States)

    Lehtimäki, Esa; Väisänen, Ari


    The digestion methods for the determination of As, Cd, Cr, Pb, Sb, Sn and Zn concentrations in plastic samples using microwave-assisted digestion (MW-AD) and small-size autoclave digestion was developed. The certified polyethylene, polypropylene, polyvinyl chloride and acrylonitrile butadiene styrene certified reference materials were used in order to find digestion method working properly for several sample matrices. Efficiency of the digestion methods was evaluated by analyzing the residual carbon in digests by TOC analyzer. MW-AD using a mixture of 7 mL of HNO3 and 3 mL of H2O2 as a digestion solution resulted in excellent recoveries for As, Cd, Pb, Sb and Zn, and were in the range of 92-107% for all the analytes except Pb in polyethylene material. Autoclave digestion using 5 mL of concentrated HNO3 as a digestion solution resulted in similar recoveries with the exception of a higher As recovery (98%). Tin recovery resulted in low level after both MW-AD and autoclave digestion. Autoclave digestion was further developed resulting in a partially open two-step digestion process especially for the determination of Sn and Cr. The method resulted in higher recoveries of Sn and Cr (87 and 76%) but with the lower concentration of easily volatile As, Cd and Sb.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  2. 7 CFR 29.6002 - Air-cured. (United States)


    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Air-cured. 29.6002 Section 29.6002 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6002 Air-cured. Tobacco cured under natural atmospheric...

  3. Alternative cancer cures: "unproven" or "disproven"? (United States)

    Vickers, Andrew


    Oncology has always coexisted with therapies offered outside of conventional cancer treatment centers and based on theories not found in biomedicine. These alternative cancer cures have often been described as "unproven," suggesting that appropriate clinical trials have not been conducted and that the therapeutic value of the treatment is unknown. Contrary to much popular and scientific writing, many alternative cancer treatments have been investigated in good quality clinical trials, and they have been shown to be ineffective. In this article, clinical trial data on a number of alternative cancer cures including Livingston-Wheeler, Di Bella Multitherapy, antineoplastons, vitamin C, hydrazine sulfate, Laetrile, and psychotherapy are reviewed. The label "unproven" is inappropriate for such therapies; it is time to assert that many alternative cancer therapies have been "disproven."

  4. Cure of HCV related liver disease. (United States)

    Shiffman, Mitchell L; Benhamou, Yves


    Chronic hepatitis C virus (HCV) causes chronic liver injury and can lead to cirrhosis and hepatocellular carcinoma (HCC). HCV can also interact with the immune system to cause several HCV related disorders including essential mixed cryoglobulinemia, vasculitis, dermatitis, glomerulonephritis and lymphoma. A strong association between HCV and diabetes mellitus also exists. These extrahepatic features may lead to increased fatigue and a reduced quality of life. It is now possible to cure most patients with chronic HCV using oral antiviral therapy. Many of these HCV-related disorders and symptoms can be cured when HCV is eradicated. However, some patients may have irreversible injury to extrahepatic sites, cirrhosis that cannot resolve, an increased risk for HCC, persistent fatigue and a reduced quality of life, despite achieving sustained virological response.

  5. Curing Reaction Model of Epoxy Asphalt Binder

    Institute of Scientific and Technical Information of China (English)

    QIAN Zhendong; CHEN Leilei; WANG Yaqi; SHEN Jialin


    In order to understand the strength developing law of the epoxy asphalt mixture,a curing reaction model of the epoxy asphalt binder was proposed based upon the thermokinetic analysis.Given some assumptions,the model was developed by applying the Kissinger law as well as Arrhenius equation,and the differential scanning calorimetry was performed for estimating the model parameters.To monitor the strength development of the epoxy asphalt mixture,a strength test program was employed and then results were compared to those produced from the proposed model.The comparative evaluation shows that a good consistency exists between the outputs from test program and the proposed model,indicating that the proposed model can be used effectively for simulating the curing reaction process for the epoxy asphalt binder and predicting the strength development for the epoxy asphalt mixture.

  6. Contactless optoelectronic technique for monitoring epoxy cure. (United States)

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


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

  7. Light-Curing Adhesive Repair Tapes (United States)

    Allred, Ronald; Haight, Andrea Hoyt


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

  8. Fast curing ethylene vinyl acetate films with dual curing agent towards application as encapsulation materials for photovoltaic modules

    Directory of Open Access Journals (Sweden)

    W-H. Ruan


    Full Text Available To speed up curing of ethylene vinyl acetate (EVA films as encapsulation materials for photovoltaic modules, a dual curing agent of benzoyl peroxide (BPO and butylperoxy 2-ethylhexyl carbonate (TBEC was introduced in this work. The experimental results indicated that for the weight ratio of BPO/TBEC of 0.6/2.4, over 80% gel content of EVA was yielded after curing at 130°C for 12 min. Compared with the case of single curing agent, the present one obviously operated at much lower temperature with faster rate. By carefully studying the influence of curing agent proportion and curing conditions on gel content of EVA films, as well as rheology and curing kinetics, the mechanism involved was analyzed and verified. The results are believed to be useful for developing new curing system of EVA encapsulation films with improved processability.

  9. Development of Cooking Test Device with Bantam Autoclave Group%群锅蒸煮实验装置的研制

    Institute of Scientific and Technical Information of China (English)

    胡明辅; 李淑兰; 陈克利; 别玉


    A set of self-made cooking test device with bantam autoclave group is introduced including its principles, main structure, body design , and operation processes. The device is mainly composed of four parts; I is a box and rack supporting the box and two motion systems ; II is the lid movement system for smoothly opening the lid and closing it tightly; IK is a autoclave group base motion system for fixing the autoclaves in the shaft rotating disc supporter and driving axis of the supporter submerged in oil using for heating the autoclaves; IV is a heating measurement and control system to complete heating the oil, measuring, displaying and controlling temperature. Cooking wood or nonwood fibrous material under different conditions in 8 or more autoclaves can simultaneously carried out during one cooking cycle. The advantages of this device are efficient, precise and even temperature control, and reliable seal.%介绍了群锅蒸煮实验装置的基本原理、主要结构、锅体设计、实验过程等.该装置主要结构包括:箱体和机架、箱盖运动系统、蒸煮群锅运动系统、加热测量控制系统.该装置的优点是一次可同时进行8锅以上蒸煮实验,同时还具有加热均匀、温度控制精确、密封可靠、操作简单的特点.

  10. Using Sex to Cure the Genome.

    Directory of Open Access Journals (Sweden)

    Eduardo P C Rocha


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

  11. Coating and curing apparatus and methods

    Energy Technology Data Exchange (ETDEWEB)

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


    Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

  12. Photothermal Monitoring Of Curing Of Polymers (United States)

    Rooney, Michael


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

  13. Sage Gene Expression Profiles Characterizing Cure (United States)


    therapies to improve breast cancer cure frequency. Down Regulation of VEGF in MTCL Cells. RNA interference has been a powerful genetic tool to study...Science 296, 550 (2002). 100. D. A. Rubinson et al., Nat Genet 33, 401 (2003). 101. E. Devroe, P. A. Silver, BMC Biotechnol 2 (2002). 102. J. P...double- plotted along the estrous cycle. Double plotting of rhythmic patterns is a standard chronobiological technique that allows visualization of

  14. An investigation on the effect of light cure and self cure composite resins on bonding strength of light cure glass ionomer to dentin (In-vitro

    Directory of Open Access Journals (Sweden)

    Pahlavan A


    Full Text Available Composite reins have recently become popular for posterior teeth restorations. Gap"nformation and subsequent microleakage are of the complications resulting from such restorations. One of the"ntechniques to overcome polymerization shrinkage of composite resins is sandwich technique (application of"nglass ionomer as a base beneath the composite resin. Since polymerization patterns in two types of composite"nresins (light cure and self cure differ from each other, various effects on the bond strength between glass"nionomer and dentin are expected."nPurpose: The aim of this in vitro study was to evaluate the effects of self- cure and light- cure composite"nresins in sandwich technique on the bond strength of light cure glass ionomer and dentin."nMaterials and Methods: 40 extracted human premolars were selected and divided into four groups:"nGroup 1: Light cure glass ionomer of 1mm thickness was placed on dentin."nGroup 2: 1mm thickness of light cure glass ionomer plus a mass of self cure composite resin of 2mm"nthickness were placed."nGroup 3: 1mm thickness of light cure glass ionomer plus light cure composite resin as two separate 1mm layer"nwere placed."nGroup 4: 1mm thickness of light cure glass ionomer with 37% phosphoric acid etching followed by two"nseparate layers of light cure composite resin of 1 mm thickness were placed."nSEM was used to determine gap size ai Gl- dentin and Gi- composite interlaces. The findings were analyzed"nby ANOVA and t-student tests."nResults: Groups 1 and 2 showed no gap at Gl-dentm interface and also cracks were not observed in all these"nspecimens. In group 3, there was gap between light cure GI and light cure composite resin and cracks were"nseen in GI, too. Group 4 showed gap at both interfaces and more cracks were seen in GI. Groups I and 2"nshowed the least gap formation and group 4 showed the most. Statistically significant difference was found"nbetween groups 3, 4 and group 1 (control, 2."nConclusion: Base

  15. Cure Behavior and Thermal Properties of Diepoxidized Cardanol Resin Cured by Electron Beam Process

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Donghwan; Cheon, Jinsil [Kumoh National Institute of Technology, Gumi (Korea, Republic of)


    Thermal curing of epoxy resin requires high temperature, time-consuming process and the volatilization of hardener. It has known that electron beam curing of epoxy resin is a fast process and occurs at low or room temperature that help reduce residual mechanical stresses in thermosetting polymers. Diepoxidized cardanol (DEC) can be synthesized by an enzymatic method from cashew nut shell liquid (CNSL), that constitutes nearly one-third of the total nut weight. A large amount of CNSL can be formed as a byproduct of the mechanical processes used to render the cashew kerneledible and its total production approaches one million tons annually, which can be bio-degradable and replace the industrial thermosetting plastics. It is expected that DEC may be cured as in an epoxy resin, which was constituted on two epoxide group and long alkyl chain, and two-types of onium salts (cationic initiator) were used as a photo-initiator. The experimental variables of this study are type and concentration of photo-initiators and electron beam dosage. In this study, the effects of initiator type and concentration on the cure behavior and the thermal properties of DEC resin processed by using electron beam technology were studied using FT-IR, TGA, TMA, DSC, and DMA. Figure 1 is the FT-IR results, showing the change of chemical structure of pure DEC and electron beam cured DEC. The characteristic absorption peak of epoxide group appeared at 850cm{sup -1}. The shape and the height were reduced when the sample was irradiated with electron beam. From this result, the epoxide groups is DEC were opened by electron beam and cured. After then, electron beam cured DEC was investigated the effect of forming 3-dimensional network.

  16. Accurate Cure Modeling for Isothermal Processing of Fast Curing Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Alexander Bernath


    Full Text Available In this work a holistic approach for the characterization and mathematical modeling of the reaction kinetics of a fast epoxy resin is shown. Major composite manufacturing processes like resin transfer molding involve isothermal curing at temperatures far below the ultimate glass transition temperature. Hence, premature vitrification occurs during curing and consequently has to be taken into account by the kinetic model. In order to show the benefit of using a complex kinetic model, the Kamal-Malkin kinetic model is compared to the Grindling kinetic model in terms of prediction quality for isothermal processing. From the selected models, only the Grindling kinetic is capable of taking into account vitrification. Non-isothermal, isothermal and combined differential scanning calorimetry (DSC measurements are conducted and processed for subsequent use for model parametrization. In order to demonstrate which DSC measurements are vital for proper cure modeling, both models are fitted to varying sets of measurements. Special attention is given to the evaluation of isothermal DSC measurements which are subject to deviations arising from unrecorded cross-linking prior to the beginning of the measurement as well as from physical aging effects. It is found that isothermal measurements are vital for accurate modeling of isothermal cure and cannot be neglected. Accurate cure predictions are achieved using the Grindling kinetic model.

  17. Cure mechanisms in materials for use in esthetic dentistry. (United States)

    Kwon, Tae-Yub; Bagheri, Rafat; Kim, Young K; Kim, Kyo-Han; Burrow, Michael F


    The current paper reviews the curing mechanisms found in resin-based materials used in dentistry. Historical aspects of dental products and the associated curing mechanisms are reviewed. In comparison with common industrial procedures, curing methods employed for dental materials are relatively limited because of the need to polymerize quickly in the oral cavity at an ambient temperature. Heat-cure and self-cure dental resins utilize benzoyl peroxide initiator alone with a tertiary amine co-initiator. At present, most dental restorative composites use a camphorquinone-amine complex initiation, visible light-cure, one-component systems, although alternative photoinitiators have been researched and developed. A multiple curing mode in a dual-cure material is a complex combination of various initiation systems. The use of aryl sulfinic acid sodium salt to overcome adverse chemical interactions between simplified adhesives and self- or dual-cure composites is based on another self-cure polymerization mechanism, sulfinic acid-initiated polymerization, proposed by Hagger in 1948. The sodium salt of aryl sulfinic acid reacts with an acidic monomer in simplified adhesives, and is believed to produce radicals. Clinically, it is important to try to optimize the degree of conversion of resin-based materials using proper manipulation and adequate light-curing techniques to ensure the best outcome for materials used to restore teeth.

  18. Rubber curing chemistry governing the orientation of layered silicate

    Directory of Open Access Journals (Sweden)


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

  19. Cure shrinkage effects in epoxy and polycyanate matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Spellman, G.P.


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


    Directory of Open Access Journals (Sweden)



    Full Text Available The main objective of this work is to compare the difference between microwave heating and conventional thermal heating in fabricating carbon/epoxy composites. Two types of epoxy resin systems were used as matrices, LY5052-HY5052 and DGEBA-HY917-DY073. All composite samples were fabricated using resin transfer moulding (RTM technique. The curing of the LY5052-HY5052-carbon and the DGEBA-HY917-DY073-carbon composite systems, were carried out at 100 °C and 120 °C, respectively. Microwave heating showed better temperature control than conventional heating, however, the heating rate of the microwave cured samples were slower than the conventionally cured samples. This was attributed to the lower power (250 W used when heating with microwaves compared to 2000 W used in conventional heating. Study of thermal characteristics as curing progressed showed that the polymerisation reaction occurred at a faster rate during microwave curing than in conventional curing for both the DGEBA and the LY/HY5052 carbon composite systems. The actual cure cycle was reduced from 60 minutes to 40 minutes when using microwaves for curing DGEBA-carbon composites. As for LY/HY5052-carbon composites, the actual cure cycle was reduced from 3 hours to 40 minutes. Both conventional and microwave heating yielded similar glass transition temperatures (120 °C for DGEBA systems and 130 °C for LY/HY5052 systems. Microwave cured composites had higher void contents than conventionally cured composites (2.2-2.8% and 1.8-2.4% for DGEBA and LY/HY5052 microwave cured composites, respectively, compared to 0.2-0.4% for both DGEBA and LY/HY5052 thermally cured composites. C-scan traces showed that all composites, regardless of methods of curing, had minimal defects.

  1. Curing Study of Epoxy/clay Nanocomposite by a New Aromatic Diamine Functional Curing Agent

    Directory of Open Access Journals (Sweden)

    Seyed Mahdi Saadati


    Full Text Available The curing behavior of an epoxy/clay nanocomposite system composed of diglycidyl ether of bisphenol A (DGEBA epoxy resin with a new aromatic diamine curing agent and organically modified clay was investigated. Epoxy/clay nanocomposite samples were prepared by mixing DGEBA, different percentages of nanoclay (1, 3, 5, 7, and 9% and 4-(4-(2,6-diphenylpyridin-4-ylphenoxybenzene-1,3-diamine (DAP. The optimum ratio of the epoxy/clay nanocomposite system (3% was investigated by total enthalpy of the curing reaction from differential scanning calorimetry (DSC thermograms. The kinetic parameters such as activation energy, pre-exponential factor, and rate constant were obtained from DSC data.

  2. Experimental Study on the Curing Effect of Dredged Sediments with Three Types of Curing Agents

    Directory of Open Access Journals (Sweden)

    Yan Lei-Ming


    Full Text Available Sediment solidification technology is widely used to dispose dredged sediment, three types of curing agents were used in this study to solidified the dredged sediment from shallows in Nantong with three types of curing agents: JY, ZL and FJ. The results showed that the optimal additive amounts of these three curing agents were 140g JY, 16g ZL, 2.0g FJ per 1000g of the dredged sediment respectively, their 28d USC were up to 2.48 MPa, 2.96 MPa and 3.00 MPa. JY has obvious early strength effect, which of FJ is not that obvious, but the later-stage strength of sediment solidified by FJ are relatively higher.


    Institute of Scientific and Technical Information of China (English)

    Fei Xie; Zong-hui Liu; De-qing Wei


    A kind of aziridine crosslinkers was synthesized and used to crosslink acrylate copolymers. The crosslinking properties and curing kinetics of the resin were studied. It was found that with the increase of the content of crosslinker in the emulsion, the mechanical properties and solvent resistance of the resin will be apparently improved, but its glass transition temperature (Tg) is very low. The lowest amount of crosslinker used in the acrylic resin emulsion is 0.25%. Curing kinetics studied by DSC show that this curing reaction occurs readily because the apparent activation energy of the reaction is low(65.1 KJ/mol). These results demonstrate that the aziridine crosslinker is indeed a low temperature crosslinking agent and can be used at room temperature.

  4. Improving a self-curing dental resin by eliminating oxygen, hydroquinone and water from its curing process. (United States)

    Keh, En-Sheng; Hayakawa, Iwao; Takahashi, Hidekazu; Watanabe, Akihiko; Iwasaki, Yasuhiko; Akiyoshi, Kazunari; Nakabayashi, Nobuo


    Self-curing dental resins are always manipulated in the presence of curing inhibitory factors such as oxygen, hydroquinone, water and another contaminants such as saliva and blood. The purpose of this study was to elucidate the effects of eliminating these curing inhibitory factors on resin properties. Several clinically relevant characteristics of an experimental resin cured in the absence of inhibitory factors (purified group) were determined and compared with the resin cured conventionally (control group). The purified group showed a significantly shorter induction period and higher reaction exotherm. It also showed significantly higher tensile strength and lower strain to failure. With regard to the amount of residual monomer, fracture toughness and fatigue strength the improvements were not significant. These findings suggest that the polymerization outcomes and mechanical properties of the purified group resin can be improved in general. Dental clinicians should pay attention to the storage and curing environments while manipulating the self-curing resin.

  5. Cure behavior of epoxy polymers used in microelectronics (United States)

    Taweeplengsangsuke, Jantrawan


    Underfill resins are used to reduce solder fatigue in flip-chip assemblies. Both underfilling and curing processes are critical to achieve reliable finished products. This study included two main themes; the development of processing diagrams for commercial underfill resins and the fundamental understanding of cure kinetics and evolution of cure stresses in model epoxies. A variety of techniques have been used to characterize the fundamental phenomena involved in the processing of underfill resins. The flow behavior, cure kinetics, cure stresses, outgassing phenomena and void formation of underfill resins were studied. Processing diagrams for underfill resins were developed by mapping fundamental phenomena involved to provide a guideline for underfilling and curing steps. With these processing diagrams one should be able to design his underfilling and curing process with scientific approach. Two commercial underfill resins, which were evaluated as part of a SEMATECH program, where shown to possess significantly different processing characteristics. However, the appropriate explanation could not be made without knowing the proprietary chemistry of the systems. Therefore, model epoxies were formulated. Three different systems were investigated; amine, imidazole, and anhydride curing agent systems. With the known chemistry, the reaction kinetics and developed cure stress can be explained more clearly. Vitrification, which severely retards the rate of reaction, was found in amine (N-aminoethylpiperazine) and anhydride (Hexahydro-4-methylphthalic anhydride) cured systems when the cure temperatures were lower than the glass transition temperature (T g) of fully cured samples; however, imidazole(2-ethyl-4-methyl-imidazole) did not show vitrification when it was cured at 20 degrees below the T g of fully cured sample due to the large exotherms. Interestingly for imidazole system, the higher cure temperature exhibited a lower Tg. This could possibly be explained by the

  6. Mechanical modeling of stress generation during cure of encapsulating resins

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.; Chambers, R.S.; Guess, T.R. (Sandia National Labs., Albuquerque, NM (USA)); Plazek, D.J.; Bero, C. (Pittsburgh Univ., PA (USA). Dept. of Materials Science and Engineering)


    We have developed a numerical model for calculating stresses generated during cure of shrinking encapsulating resins. Mechanical modeling of polymer encapsulated electronic devices usually focuses on stress generated during cooling after cure. The stress developed during cure, due to shrinkage of the encapsulant, is normally neglected. That assumption is valid if both the shear and bulk moduli of the encapsulant at the cure temperature are negligible with respect to the moduli at lower temperatures. Our measurements on a model epoxy encapsulant show that the shear modulus during cure, varying from 0 to 6 MPa, is at least 100 times smaller than that at ambient temperature. In contrast, the bulk modulus at the cure temperature is only 2.5 times smaller. Since the bulk modulus during cure cannot be neglected, significant stress can be produced if volume shrinkage is constrained by a stiff mold or embedded elements. In fact, mechanical failure of encapsulating materials during cure has been evident in some of our experiments. Using measurements of shear and bulk moduli plus volume shrinkage as inputs to a finite element model, we have successfully predicted the shrinkage strains and stresses developed during cure of a model epoxy resin inside a cylindrical tube. Consideration of cure shrinkage stress has led to a process modification that appears to reduce mechanical failures in a real encapsulated device. 6 refs., 6 figs.

  7. Influence of curing protocol on selected properties of light-curing polymers

    DEFF Research Database (Denmark)

    Dewaele, Magali; Asmussen, Erik; Peutzfeldt, Anne;


    The purpose of this study was to investigate the effect of light-curing protocol on degree of conversion (DC), volume contraction (C), elastic modulus (E), and glass transition temperature (T(g)) as measured on a model polymer. It was a further aim to correlate the measured values with each other....

  8. Research on Optimization of Mold Temperature Fields in Autoclave Age Forming%热压罐时效成形模具温度场优化研究

    Institute of Scientific and Technical Information of China (English)

    张旭生; 甘忠; 张海燕


    In the process of autoclave age forming, temperature is the most important parameter. Molds and different sections of parts experience temperature difference during the forming process of aircraft integrated panels. Aiming at improving forming qualities, decreasing the temperature difference and homogenizing temperature fields, it analyzes several different types of hole optimizing schemes through simulation of the autoclave and the mold with application software computational fluid mechanics FLUENT. Results show that in the T- shaped wind road, the mould surface temperature field uniformity is the best.%通过计算流体力学方法(CFD),应用软件FLUENT对热压罐以及模具进行建模模拟,对一字型、十字型、T型3种不同风道进行了模拟仿真.分析结果表明,T型风道对改善温度场均匀性效果最优.

  9. Radiation curing of carbon fibre composites (United States)

    Spadaro, G.; Alessi, S.; Dispenza, C.; Sabatino, M. A.; Pitarresi, G.; Tumino, D.; Przbytniak, G.


    Epoxy/carbon fibre reinforced composites were produced by means of e-beam irradiation through a pulsed 10 MeV electron beam accelerator. The matrix consisted of a difunctional epoxy monomer (DGEBA) and an initiator of cationic polymerisation, while the reinforcement was a unidirectional high modulus carbon fibre fabric. Dynamic mechanical thermal analysis was carried out in order to determine the cross-linking degree. The analysis pointed out a nonuniformity in the cross-linking degree of the e-beam cured panels, with the formation of clusters at low Tg (glass transition temperature) and clusters at high Tg. An out-of-mould post irradiation thermal treatment on e-beam cured samples provides a higher uniformity in the network although some slight degradation effects. Mode I delamination fracture toughness and Interlaminar Shear Strength (ISS) were also investigated by means of Double Cantilever Beam (DCB) and Short Beam Shear tests, respectively. Results from this mechanical characterisation allowed to correlate fracture toughness of the bulk matrix resin, cross-linking density and fibre/matrix interaction to the delamination fracture behaviour of the fibre reinforced material.

  10. CURE: Clean use of reactor energy

    Energy Technology Data Exchange (ETDEWEB)



    This paper presents the results of a joint Westinghouse Hanford Company (Westinghouse Hanford)-Pacific Northwest Laboratory (PNL) study that considered the feasibility of treating radioactive waste before disposal to reduce the inventory of long-lived radionuclides, making the waste more suitable for geologic disposal. The treatment considered here is one in which waste would be chemically separated so that long-lived radionuclides can be treated using specific processes appropriate for the nuclide. The technical feasibility of enhancing repository performance by this type of treatment is considered in this report. A joint Westinghouse Hanford-PNL study group developed a concept called the Clean Use of Reactor Energy (CURE), and evaluated the potential of current technology to reduce the long-lived radionuclide content in waste from the nuclear power industry. The CURE process consists of three components: chemical separation of elements that have significant quantities of long-lived radioisotopes in the waste, exposure in a neutron flux to transmute the radioisotopes to stable nuclides, and packaging of radionuclides that cannot be transmuted easily for storage or geologic disposal. 76 refs., 32 figs., 24 tabs.

  11. Dilute phosphoric acid-catalysed hydrolysis of municipal bio-waste wood shavings using autoclave parr reactor system. (United States)

    Orozco, Angela M; Al-Muhtaseb, Ala'a H; Albadarin, Ahmad B; Rooney, David; Walker, Gavin M; Ahmad, Mohammad N M


    The visibility of using municipal bio-waste, wood shavings, as a potential feedstock for ethanol production was investigated. Dilute acid hydrolysis of wood shavings with H₃PO₄ was undertaken in autoclave parr reactor. A combined severity factor (CSF) was used to integrate the effects of hydrolysis times, temperature and acid concentration into a single variable. Xylose concentration reached a maximum value of 17 g/100 g dry mass corresponding to a yield of 100% at the best identified conditions of 2.5 wt.% H₃PO₄, 175 °C and 10 min reaction time corresponding to a CSF of 1.9. However, for glucose, an average yield of 30% was obtained at 5 wt.% H₃PO₄, 200 °C and 10 min. Xylose production increased with increasing temperature and acid concentration, but its transformation to the degradation product furfural was also catalysed by those factors. The maximum furfural formed was 3 g/100 g dry mass, corresponding to the 24% yield.

  12. Interaction of aluminum with PHFtau in Alzheimer's disease neurofibrillary degeneration evidenced by desferrioxamine-assisted chelating autoclave method. (United States)

    Murayama, H; Shin, R W; Higuchi, J; Shibuya, S; Muramoto, T; Kitamoto, T


    To demonstrate that aluminum III (Al) interacts with PHFtau in neurofibrillary degeneration (NFD) of Alzheimer's disease (AD) brain, we developed a "chelating autoclave method" that allows Al chelation by using trivalent-cationic chelator desferrioxamine. Its application to AD brain sections before Morin histochemistry for Al attenuated the positive fluorescence of neurofibrillary tangles, indicating Al removal from them. This method, applied for immunostaining with phosphorylation-dependent anti-tau antibodies, significantly enhanced the PHFtau immunoreactivity of the NFD. These results suggest that each of the phosphorylated epitopes in PHFtau are partially masked by Al binding. Incubation of AD sections with AlCl(3) before Morin staining revealed Al accumulation with association to neurofibrillary tangles. Such incubation before immunostaining with the phosphorylation-dependent anti-tau antibodies abolished the immunolabeling of the NFD and this abolition was reversed by the Al chelation. These findings indicate cumulative Al binding to and thereby antigenic masking of the phosphorylated epitopes of PHFtau. Al binding was further documented for electrophoretically-resolved PHFtau on immunoblots, indicating direct Al binding to PHFtau. In vitro aggregation by AlCl(3) was observed for PHFtau but was lost on dephosphorylation of PHFtau. Taken together, phosphorylation-dependent and direct PHFtau-Al interaction occurs in the NFD of the AD brain.

  13. Reformulating polycaprolactone fumarate to eliminate toxic diethylene glycol: effects of polymeric branching and autoclave sterilization on material properties. (United States)

    Runge, M Brett; Wang, Huan; Spinner, Robert J; Windebank, Anthony J; Yaszemski, Michael J


    Polycaprolactone fumarate (PCLF) is a cross-linkable derivative of polycaprolactone diol that has been shown to be an effective nerve conduit material that supports regeneration across segmental nerve defects and has warranted future clinical trials. Degradation of PCLF (PCLF(DEG)) releases toxic small molecules of diethylene glycol used as the initiator for the synthesis of polycaprolactone diol. In an effort to eliminate this toxic degradation product we present a strategy for the synthesis of PCLF from either propylene glycol (PCLF(PPD)) or glycerol (PCLF(GLY)). PCLF(PPD) is linear and resembles the previously studied PCLF(DEG), while PCLF(GLY) is branched and exhibits dramatically different material properties. The synthesis and characterization of their thermal, rheological, and mechanical properties are reported. The results show that the linear PCLF(PPD) has material properties similar to the previously studied PCLF(DEG). The branched PCLF(GLY) exhibits dramatically lower crystalline properties resulting in lower rheological and mechanical moduli, and is therefore a more compliant material. In addition, the question of an appropriate Food and Drug Administration approvable sterilization method is addressed. This study shows that autoclave sterilization of PCLF materials is an acceptable sterilization method for cross-linked PCLF and has minimal effect on the PCLF thermal and mechanical properties.

  14. 利用油页岩灰制备蒸压砖的试验研究%Study on preparation of autoclaved brick with oil shale ash

    Institute of Scientific and Technical Information of China (English)

    高子栋; 潘红


    The autoclaved brick is prepared with the oil shale ash, the fly ash, the calcium carbide residue, the gyp⁃sum and the stone chips. The effect on properties of autoclaved brick is studied by changing the ratio of oil shale ash and fly ash. When the ratio of oil shale ash increases, the compressive strength and the flexural strength of au⁃toclaved brick increase first, and then decrease, and the drying shrinkage value keep increasing. When the ratio of oil shale ash is 30%, the strength grade of autoclaved brick could achieves MU15. When the ratio of oil shale ash is 50%, the strength grade of autoclaved brick could also achieve MU10.%采用油页岩灰、粉煤灰、电石渣、石膏、石屑等作为原材料,制备了一种蒸压砖,研究了油页岩灰替代粉煤灰的比例对产品性能的影响。试验结果表明,随油页岩灰比例不断增大,蒸压砖的抗压强度、抗折强度均呈先提高后降低的变化趋势,干燥收缩值不断提高。当油页岩灰替代粉煤灰的比例为30%时,蒸压砖强度等级可达到标准JC239—2001《粉煤灰砖》中的MU15;当油页岩灰替代粉煤灰的比例为50%时,蒸压砖强度等级仍可达到MU10。

  15. In situ cure monitoring of advanced fiber reinforced composites (United States)

    Powell, Graham R.; Crosby, Peter A.; Fernando, Gerard F.; France, Chris M.; Spooncer, Ronald C.; Waters, David N.


    This paper describes a comparative study of in-situ cure monitoring and cure modelling by three methods: (a) evanescent wave spectroscopy, (b) refractive index change, (c) near- infrared spectroscopy. Optical fibers were embedded into aerospace epoxy resins during the manufacturing process of the composite. The cure characteristics were then tracked in real- time during the processing of the material via evanescent wave interaction. This technique is based upon monitoring of characteristic infrared absorption bands of the resin system to find the concentration of the epoxy and amine hardener as a function of cure time. Hence this technique is suitable for on-line process monitoring and optimization. Results obtained from the optical fiber sensors were used to model the curing behavior of the resin system. The results were compared with near-infrared spectroscopy and differential scanning calorimetry experiments carried out under similar conditions. The feasibility of utilizing refractive index changes to monitor the extent of cure has also been demonstrated.

  16. Photoacoustic monitoring of inhomogeneous curing processes in polystyrene emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Luna, M.; Gutierrez-Juarez, G.; Rodriguez-Vizcaino, J.M.; Varela-Nsjera, J.B.; Rodriguez-Palencia, J.M.; Bernal-Alvarado, J.; Sosa, M. [Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico); Alvarado-Gil, J.J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Antigua Carretera a Progreso, Merida, Yucatan (Mexico)


    The time evolution of the inhomogeneous curing process of polystyrene emulsions is studied using a variant of the conventional photoacoustic (PA) technique. The thermal effusivity, as a function of time, is determined in order to monitor the sintering process of a styrene emulsion in different steps of the manufacturing procedure. PA measurements of thermal effusivity show a sigmoidal growth as a function of time during the curing process. The parameterization of these curves permits the determination of the characteristic curing time and velocity of the process. A decreasing of the curing time and an increasing curing velocity for the final steps of the manufacturing process are observed. The feasibility of our approach and its potentiality for the characterization of other curing process are discussed. (author)

  17. Experimental and numerical study of heterogeneous pressure-temperature-induced lethal and sublethal injury of Lactococcus lactis in a medium scale high-pressure autoclave. (United States)

    Kilimann, K V; Kitsubun, P; Delgado, A; Gänzle, M G; Chapleau, N; Le Bail, A; Hartmann, C


    The present contribution is dedicated to experimental and theoretical assessment of microbiological process heterogeneities of the high-pressure (HP) inactivation of Lactococcus lactis ssp. cremoris MG 1363. The inactivation kinetics are determined in dependence of pressure, process time, temperature and absence or presence of co-solutes in the buffer system namely 4 M sodium chloride and 1.5 M sucrose. The kinetic analysis is carried out in a 0.1-L autoclave in order to minimise thermal and convective effects. Upon these data, a deterministic inactivation model is formulated with the logistic equation. Its independent variables represent the counts of viable cells (viable but injured) and of the stress-resistant cells (viable and not injured). This model is then coupled to a thermo-fluiddynamical simulation method, high-pressure computer fluid dynamics technique (HP-CFD), which yields spatiotemporal temperature and flow fields occurring during the HP application inside any considered autoclave. Besides the thermo-fluiddynamic quantities, the coupled model predicts also the spatiotemporal distribution of both viable (VC) and stress-resistant cell counts (SRC). In order to assess the process non-uniformity of the microbial inactivation in a 3.3-L autoclave experimentally, microbial samples are placed at two distinct locations and are exposed to various process conditions. It can be shown with both, experimental and theoretical models that thermal heterogeneities induce process non-uniformities of more than one decimal power in the counts of the viable cells at the end of the treatment.

  18. The effect of multiple autoclave cycles on the surface of rotary nickel-titanium endodontic files: An in vitro atomic force microscopy investigation

    Directory of Open Access Journals (Sweden)

    Ashish Shashikant Nair


    Full Text Available Aims: To observe and study the effect of multiple autoclave sterilization cycles, on the surface of nickel-titanium (NiTi files. Materials and Methods: The file used for this study was the M two file (VDW and ProTaper (Dentsply. The apical 5 mm of the files were attached to a silicon wafer and subjected to autoclave cycles under standardized conditions. They were scanned with an AFM after 1, 5, and 10 cycles. The unsterilized files were used as control, before start of the study. Three vertical topographic parameters namely maximum height (MH, root mean square (RMS of surface roughness, and arithmetic mean roughness (AMRwere measured with the atomic force microscope (AFM. Analysis of variance along with Tukey′s test was used to test the differences. Results: The vertical topographic parameters were higher for both the files, right after the first cycle, when compared with the control (P < 0.01. The surface roughness increased sharply for M two when compared to ProTaper, though ProTaper had a rougher surface initially. Conclusions: The study confirmed that the irregularities present on the surface of the file became more prominent with multiple autoclave cycles, a fact that should be kept in mind during their reuse.

  19. Process Formulations And Curing Conditions That Affect Saltstone Properties

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. M.; Pickenheim, B. R.; Daniel, W. E.


    The first objective of this study was to analyze saltstone fresh properties to determine the feasibility of reducing the formulation water to premix (w/p) ratio while varying the amount of extra water and admixtures used during processing at the Saltstone Production Facility (SPF). The second part of this study was to provide information for understanding the impact of curing conditions (cure temperature, relative humidity (RH)) and processing formulation on the performance properties of cured saltstone.

  20. The curing process of layered silicate/epoxy nanocomposites


    Nieminen, Ilkka


    The industrial methods of processing polymeric thermoset matrix nanocomposites require a good knowledge of the matrix curing process. The dispersion of nanoparticles in the matrix effects the curing process due to the interaction between nanoparticles and the matrix at the atomic level, especially when the nanoparticles have been treated with a surfactant agent ( alquilammonium) that is in competition with the reactive groups of the hardener. This thesis investigates the curing process o...

  1. 浅谈粉煤灰蒸压釜安装的几个要点%Talking about Several Key Points in the Installation of Fly-ash Autoclaved Kettle

    Institute of Scientific and Technical Information of China (English)



    详细介绍了粉煤灰蒸压釜安装过程中的几个要点,并提出了粉煤灰蒸压釜安装过程中需要注意的事项。%This paper introduces in detail several key points in the installation of fly-ash autoclaved kettle, and puts forward the matters needing attention in the installation of fly-ash autoclaved kettle.

  2. Optical fibre grating refractometers for resin cure monitoring (United States)

    Buggy, S. J.; Chehura, E.; James, S. W.; Tatam, R. P.


    The use of fibre grating refractometers as a means of monitoring the cure of a UV-cured epoxy resin is presented. The wavelength shift of the attenuation bands of a long period grating and the spectral response of a tilted fibre Bragg grating sensor were measured simultaneously during the cure of the resin and compared with measurements made using a fibre optic Fresnel-based refractometer. The results showed a good correlation (6 × 10-3 rius) and illustrate the potential of the techniques for non-invasive composite material cure monitoring.

  3. Curing Methods and Their Effects on The Strength of Concrete


    Nuruddeen Usman; Muhammad Nura Isa


    There are a lot of arguments on which method of curing concrete gives good strength. These different opinions results into this study, which aim at investigating the effects of different curing methods on the strength of concrete. Laboratory test was employed for this study. Normal concretes were prepared using specified mix ratio of 1:2:4 and 1:3:6. The cubes tested for compressive strength at 3, 7, 21, and 28 days of curing respectively using four curing methods namely immersion...

  4. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel Part 1: 8-Ply In-Autoclave Facesheets. Part 1; 8-Ply In-Autoclave Facesheets (United States)

    Myers, David E.; Pineda, Evan J.; Zalewski, Bart F.; Kosareo, Daniel N.; Kellas, Sotiris


    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10-m diameter barrel section of the heavy lift launch vehicle, were manufactured under the NASA Composites for Exploration program and the NASA Space Launch Systems program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: inautoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3.00- by 5.00-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center. Furthermore, linear eigenvalue and geometrically nonlinear finite element analysis was performed to predict the compressive response of the 3.00- by 5.00-ft panels. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panel composed of 8-ply, IM7/977-3 facesheets (referred to Panel A). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yield good qualitative and quantitative predictions. Additionally, it was predicted correctly that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber misalignments, and three-dimensional (3 D) effects on the compressive response of the panel.

  5. Ambient Cured Alkali Activated Flyash Masonry Units (United States)

    Venugopal, K.; Radhakrishna; Sasalatti, Vinod M.


    Geopolymers belong to a category of non-conventional and non-Portland cement based cementitious binders which are produced using industrial by products like fly ash and ground granulated blast furnace slag (GGBFS). This paper reports on the development of geopolymer mortars for production of masonry units. The geopolymer mortars were prepared by mixing various by products with manufactured sand and a liquid mixture of sodium silicate and sodium hydroxide solutions. After curing at ambient conditions, the masonry units were tested for strength properties such as water absorption, initial rate of absorption, compression, shear- bond, and stress-strain behaviour etc. It was observed that the flexural strength of the blocks is more than 2 MPa and shear bond strength is more than 0.4MPa. It was found that the properties of geopolymer blocks were superior to the traditional masonry units. Hence they can be recommended for structural masonry.

  6. Helicobacter pylori: Basic Mechanisms to Clinical Cure

    Directory of Open Access Journals (Sweden)

    ABR Thomson


    Full Text Available Since its rediscovery 10 years ago, Helicobacter pylori has reshaped our thinking about the course of peptic ulcer disease. Our approach to the patient with a duodenal ulcer has become one of attempting eradication therapy at the time of first diagnosis, in the hope of curing the ulcer disease. Gastric and duodenal ulceration are only two of the manifestations of this chronic antral infection; other complications of H pylori include gastritis, gastric cancer and possible maltomas. Therapy of H pylori infection is complicated and involves dual therapy with an antibiotic plus a protein pump inhibitor, such as omeprazole 20 mg bid plus amoxicillin 1 g bid for two weeks, triple or quadruple therapy with bismuth, two antibiotics and an H2-receptor antagonist. Vaccination against H pylori is on the far horizon.

  7. Brane polarization is no cure for tachyons

    CERN Document Server

    Bena, Iosif


    Anti-M2 and anti-D3 branes placed in regions with charges dissolved in fluxes have a tachyon in their near-horizon region, which causes these branes to repel each other. If the branes are on the Coulomb branch this tachyon gives rise to a runaway behavior, but when the branes are polarized into five-branes this tachyon only appears to lower the energy of the polarized branes, without affecting its stability. We analyze brane polarization in the presence of a brane-brane-repelling tachyon and show that when the branes are polarized along the direction of the tachyon the polarized shell is unstable. This implies that tachyons cannot be cured by brane polarization and indicates that, at least in a certain regime of parameters, anti-D3 branes polarized into NS5 branes at the bottom of the Klebanov-Strassler solution have an instability.

  8. Stratospheric experiments on curing of composite materials (United States)

    Chudinov, Viacheslav; Kondyurin, Alexey; Svistkov, Alexander L.; Efremov, Denis; Demin, Anton; Terpugov, Viktor; Rusakov, Sergey


    Future space exploration requires a large light-weight structure for habitats, greenhouses, space bases, space factories and other constructions. A new approach enabling large-size constructions in space relies on the use of the technology of polymerization of fiber-filled composites with a curable polymer matrix applied in the free space environment on Erath orbit. In orbit, the material is exposed to high vacuum, dramatic temperature changes, plasma of free space due to cosmic rays, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The development of appropriate polymer matrix composites requires an understanding of the chemical processes of polymer matrix curing under the specific free space conditions to be encountered. The goal of the stratospheric flight experiment is an investigation of the effect of the stratospheric conditions on the uncured polymer matrix of the composite material. The unique combination of low residual pressure, high intensity UV radiation including short-wave UV component, cosmic rays and other aspects associated with solar irradiation strongly influences the chemical processes in polymeric materials. We have done the stratospheric flight experiments with uncured composites (prepreg). A balloon with payload equipped with heater, temperature/pressure/irradiation sensors, microprocessor, carrying the samples of uncured prepreg has been launched to stratosphere of 25-30 km altitude. After the flight, the samples have been tested with FTIR, gel-fraction, tensile test and DMA. The effect of cosmic radiation has been observed. The composite was successfully cured during the stratospheric flight. The study was supported by RFBR grants 12-08-00970 and 14-08-96011.

  9. Curing of epoxy matrix composite in stratosphere (United States)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela

    Large structures for habitats, greenhouses, space bases, space factories are needed for next stage of space exploitation. A new approach enabling large-size constructions in space relies on the use of the polymerization technology of fiber-filled composites with a curable polymer matrix applied in the free space environment. The polymerisation process is proposed for the material exposed to high vacuum, dramatic temperature changes, space plasma, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The stratospheric flight experiments are directed to an investigation of the curing polymer matrix under the stratospheric conditions on. The unique combination of low atmospheric pressure, high intensity UV radiation including short wavelength UV and diurnal temperature variations associated with solar irradiation strongly influences the chemical processes in polymeric materials. The first flight experiment with uncured composites was a part of the NASA scientific balloon flight program realised at the NASA stratospheric balloon station in Alice Springs, Australia. A flight cassette installed on payload was lifted with a “zero-pressure” stratospheric balloon filled with Helium. Columbia Scientific Balloon Facility (CSBF) provided the launch, flight telemetry and landing of the balloon and payload. A cassette of uncured composite materials with an epoxy resin matrix was exposed 3 days in the stratosphere (40 km altitude). The second flight experiment was realised in South Australia in 2012, when the cassette was exposed in 27 km altitude. An analysis of the chemical structure of the composites showed, that the space irradiations are responsible for crosslinking of the uncured polymers exposed in the stratosphere. The first prepreg in the world was cured successfully in stratosphere. The investigations were supported by Alexander von Humboldt Foundation, NASA and RFBR (12-08-00970) grants.

  10. Influence of curing tip distance on resin composite Knoop hardness number, using three different light curing units. (United States)

    Caldas, Danilo Biazzetto de Menezes; de Almeida, Janaina Bertoncelo; Correr-Sobrinho, Lourenço; Sinhoreti, Mário Alexandre Coelho; Consani, Simonides


    This in vitro study evaluated the influence of curing tip distance on the Knoop Hardness Number (KHN) of a resin composite when using three different light curing units: (1) a halogen light (XL 1500 curing unit-3M), (2) a "softstart-polymerization" (Elipar Trilight curing in an exponential mode-ESPE) and (3) a PAC (Apolo 95E curing unit-DMD). The resin composite, Filtek Z250 (3M), was cured by these curing units at three light-tip distances from the resin composite: 0 mm, 6 mm and 12 mm. The resin composite specimens were flattened to their middle portion and submitted to 18 KHN measurements perspecimen. The results showed that for the Elipar Trilight unit, the hardness of the resin composite decreased as the light tip distance increased. The XL 1500 unit presented a significant decrease in hardness as the depth of cure of the resin composite increased. Apolo 95E caused a decrease in the resin composite hardness values when the depth of cure and light tip distance increased.

  11. Cure Kinetics of DGEBA with Hyperbranched Poly(3-hydroxyphenyl) Phosphate as Curing Agent Studied by Non-isothermal DSC

    Institute of Scientific and Technical Information of China (English)


    The cure kinetics of diglycidyl ether of bisphenol A(DGEBA) with hyperbranched poly(3-hydroxyphenyl) phosphate(HHPP) as the curing agent was investigated by means of non-isothermal differential scanning calorimetry(DSC) at various heating rates. The results were compared with the corresponding results by using 1,3-dihydroxybenzene(DHB) as a model compound. The results show that HHPP can enhance the cure reaction of DGEBA, resulting in the decrease of the peak temperature of the curing curve as well as the decrease of the activation energy because of the flexible -P-O- groups in the backbone of HHPP. However, both the activation energy of the cured polymer and the peak temperature of the curing curve are increased with DHB as a curing agent. The cure kinetics of the DGEBA/HHPP system was calculated by using the isoconversional method given by Málek. It was found that the two-parameter autocatalytic model(esták-Berggren equation) is the most adequate one to describe the cure kinetics of the studied system at various heating rates. The obtained non-isothermal DSC curves from the experimental data show the results being accordant with those theoretically calculated.

  12. The effect of curing time and curing method on microleakge of conservative adhesive resin restorations: an in vitro study

    Directory of Open Access Journals (Sweden)

    Alireza Heidari


    Full Text Available Background and Aims: Using the conservative adhesive resin restoration (CAR in uncooperative children lead to numerous problems because of being time consuming. The purpose of this study was to compare the microleakage of conservative adhesive resin restoration under separate curing and co-curing.Materials and Methods: In this experimental study, 120 intact premolar teeth were collected and 120 vertical grooves were prepared on them. Then the teeth were divided into four groups: group 1, separated curing of bonding agent, flowable composite and sealant; group 2, co-curing of all materials for 60 seconds; group 3,co-curing of all materials for 40 seconds and group 4, co-curing of all materials for 20 seconds. Then the specimens were thermocycled and immersed in basic fuchsin solution. The teeth were sectioned horizontally and dye penetration was evaluated with stereomicroscope. Date were analyzed using one-way ANOVA and Scheffe test.Results: Mean value of dye penetration in groups 1, 2, 3, and 4 was 1.53±0.6, 2.06±0.6, 2.5±0.7 and 3.53±0.6, respectively. There was a statistically significant difference between group 1 and the other groups (P=0.0001.Conclusion: Considering the problems caused by microleakage in conservative resin adhesive restorations, co-curing method should not be used. In the case of using co-curing method, 60 second curing time is suggested for sufficient polymerization.

  13. Micromechanical properties of veneer luting resins after curing through ceramics. (United States)

    Oztürk, Elif; Hickel, Reinhard; Bolay, Sükran; Ilie, Nicoleta


    The aim of this study was to assess the performance of light-cured luting resin after curing under the ceramic restoration in comparison to dual-cured luting resin, by evaluating the micromechanical properties. Two hundred seventy thin luting composite films of ca. 170 μm in thickness were prepared by using two light-cured luting resins (Variolink Veneer, Ivoclar Vivadent; RelyX Veneer, 3M ESPE) and a dual-cured luting resin (Variolink II, Ivoclar Vivadent). The composites were cured by using a LED-unit (Bluephase®, Ivoclar Vivadent) with three different curing times (10, 20, and 30 s) under two ceramics (IPS e.max Press, Ivoclar Vivadent; IPS Empress® CAD, Ivoclar Vivadent) of different thicknesses (0, 0.75, and 2 mm). Forty-five groups were included, each containing six thin films. The samples were stored after curing for 24 h at 37°C by maintaining moisture conditions with distilled water. Micromechanical properties of the composites were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). For each sample, ten indentations were made, thus totalizing 60 measurements per group. Micromechanical properties of the luting resins were statistically analyzed (SPSS 17.0). Significant differences were observed between the micromechanical properties of the luting resins (p mechanical properties compared to the light-cured luting resins. The effect of luting resin type on the micromechanical properties of the luting resins was higher than the effect of curing time, ceramic type and ceramic thickness respectively (*The values of reference without ceramics for 30 s curing time).

  14. Hardening of a dual-cure resin cement using QTH and LED curing units


    Santos,Maria Jacinta Moraes Coelho; Passos, Sheila Pestana; Encarnação, Monalisa Olga Lessa da; Santos Junior,Gildo Coelho; Bottino, Marco Antonio [UNESP


    p. 110-115 OBJECTIVE: This study evaluated the surface hardness of a resin cement (RelyX ARC) photoactivated through indirect composite resin (Cristobal) disks of different thicknesses using either a light-emitting diode (LED) or quartz tungsten halogen (QTH) light source. MATERIAL AND METHODS: Eighteen resin cement specimens were prepared and divided into 6 groups according to the type of curing unit and the thickness of resin disks interposed between the cement surface and light sourc...

  15. Immunization against leishmaniasis by PLGA nanospheres loaded with an experimental autoclaved Leishmania major (ALM) and Quillaja saponins. (United States)

    Tafaghodi, M; Eskandari, M; Kharazizadeh, M; Khamesipour, A; Jaafari, M R


    Immune responses against the Leishmania antigens are not sufficient to protect against a leishmania challenge. Therefore these antigens need to be potentiated by various adjuvants and delivery systems. In this study, Poly (d,l-lactide-co-glycolide (PLGA) nanospheres as antigen delivery system and Quillaja saponins (QS) as immunoadjuvant have been used to enhance the immune response against autoclaved Leishmania major (ALM). PLGA nanospheres were prepared by a double-emulsion (W/O/W) technique. Particulate characteristics were studied by scanning electron microscopy and particle size analysis. Mean diameter for nanospheres loaded with ALM+QS was 294 ± 106 nm. BALB/c mice were immunized three times in 3-weeks intervals using ALM plus QS loaded nanospheres [(ALM+QS)PLGA], ALM encapsulated with PLGA nanospheres [(ALM)PLGA], (ALM)PLGA + QS, ALM + QS, ALM alone or PBS. The intensity of infection induced by L. major challenge was assessed by measuring size of footpad swelling. The strongest protection, showed by significantly (P < 0.05) smaller footpad, were observed in mice immunized with (ALM)PLGA. The (ALM+QS)PLGA group showed the least protection and highest swelling, while the (ALM)PLGA+QS, ALM+QS and ALM showed an intermediate protection with no significant difference. The mice immunized with ALM and ALM+QS showed the highest IgG2a/IgG1 ratio (P < 0.01), followed by (ALM)PLGA+QS. The highest IFN-γ and lowest IL-4 production was seen in (ALM)PLGA+QS, ALM+QS groups. The highest parasite burden was observed in (ALM)PLGA+QS and (ALM+QS)PLGA groups. It is concluded that PLGA nanospheres as a vaccine delivery system could increase the protective immune responses, but QS adjuvant has a reverse effect on protective immune responses and the least protective responses were seen in the presence of this adjuvant.

  16. Immunization against leishmaniasis by PLGA nanospheres encapsulated with autoclaved Leishmania major (ALM) and CpG-ODN. (United States)

    Tafaghodi, Mohsen; Khamesipour, Ali; Jaafari, Mahmoud R


    Various adjuvants and delivery systems have been evaluated for increasing the protective immune responses against leishmaniasis and mostly have been shown not to be effective enough. In this study, poly(D,L-lactide-co-glycolide) (PLGA) nanospheres as an antigen delivery system and CpG-ODN as an immunoadjuvant have been used for the first time to enhance the immune response against autoclaved Leishmania major (ALM). PLGA nanospheres were prepared by a double-emulsion (W/O/W) technique. Particulate characteristics were studied by scanning electron microscopy and particle size analysis. Mean diameter of ALM + CpG-ODN-loaded nanospheres was 300 ± 128 nm. BALB/c mice were immunized three times in 3-week intervals using ALM plus CpG-ODN-loaded nanospheres [(ALM + CpG-ODN)(PLGA)], ALM encapsulated PLGA nanospheres [(ALM)(PLGA)], (ALM)(PLGA) + CpG, ALM + CpG, ALM alone, or phosphate buffer solution (PBS). The intensity of infection induced by L. major challenge was assessed by measuring size of footpad swelling. The strongest protection, showed by significantly (P<0.05) smaller footpad, was observed in mice immunized with (ALM + CpG-ODN)(PLGA). The (ALM)(PLGA), (ALM)(PLGA) + CpG, and ALM + CpG were also showed a significantly (P<0.05) smaller footpad swelling compared to the groups received either PBS or ALM alone. The mice immunized with (ALM + CpG-ODN)(PLGA), (ALM)(PLGA) + CpG, and ALM + CpG showed the highest IgG2a/IgG1 ratio, interferon-γ production, and lowest interleukin-4 production compared to the other groups. It is concluded that when both PLGA nanospheres and CpG-ODN adjuvants were used simultaneously, it induce stronger immune response and enhance protection rate against Leishmania infection.


    Directory of Open Access Journals (Sweden)



    Full Text Available An Experimental study was conducted to assess the Acid resistance of flyash based geopolymer mortar specimens of size 50x50x50mm with a ratio of flyash to sand as 1:3.The ratio between solution(Sodiumhydroxide and Sodium silicate solution to flyash were 0.376,0.386,0.396 and 0.416. After casting the specimens were subjected to both ambient curing and heat curing. In heat curing the specimens were kept continuously at 60oC for 24 hrs. Durability of specimens was assessed by immersing them in 5% of sulfuric acid and 5%hydrochloric acid for a period of 14 weeks. Evaluation of its resistance in terms of change in weight, compressive strength and visual appearance at regular intervals was carried out. After exposure in the acid solutions for 14 weeks, the samples showed very low weight loss. Results obtained from the present study indicate that Geopolymers are highly resistance to sulfuric acid and hydrochloric acid.

  18. Cure Behaviors of epoxy resin initiated by methylanilinium slats as latent cationic curing agent.

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J.; Kim, T.J.; Lee, C.J.; Lee, J.R. [Korea Research Institute of Chemical Technology, Taejeon (Korea); Park, J.K.; Shin, J.H. [Seoul National University, Seoul (Korea)


    The effect of novel N-crotyl-N, N-dimethyl-4-methylanilinium hexafluoroantimonate (CMH) curing agent as a thermal latent initiator on thermal behaviors, rheological properties, and thermal stability of diglycidylether of bisphenol A (DGEBA) epoxy cationic system was investigated. From DSC measurements of DGEBA/CMH system, it was shown that this system exhibits an excellent thermal latent characteristic at a given temperature. The conversion and conversion rate of DGEBA/CMH system increased with increasing the concentration of initiator, due to high activity of CMH. Rheological properties of the system were investigated under isothermal condition using a rheometer. The gelation time was obtained from the analysis of storage modulus (G'), loss modulus (G''), and damping factor (tan {delta}). As a result, the reduction of gelation time was affected by high curing temperature and concentration of CMH, resulting in high degree of network formation in cationic polymerization, due to difference of activity. The thermal stability of the cured epoxy resin was discussed in terms of the activation energy for decomposition and thermal factors determined from TGA measurements. (author). 29 refs., 3 tabs., 10 figs.

  19. Improved method facilitates debulking and curing of phenolic impregnated asbestos (United States)

    Gaines, P.


    Workpieces covered with phenolic impregnated asbestos tape and then wrapped with a specified thickness of nylon yarn under pressure, are debulked and cured in a standard oven. This method of debulking and curing is used in the fabrication of ablative chambers for the Gemini and Apollo attitude control engines.

  20. Isothermal epoxy-cure monitoring using nonlinear ultrasonics

    NARCIS (Netherlands)

    Koissin, V.; Demcenko, A.; Korneev, V.A.


    Isothermal curing of LY 1564SP resin in an aluminium-adhesive-aluminium laminate is investigated, using a nonlinear ultrasonic immersion technique, to prove its applicability for this type of dynamic material transformation. For verification and comparison, epoxy-cure kinetics and rheological behavi

  1. Shortest exposure time possible with LED curing lights

    NARCIS (Netherlands)

    Busemann, I.; Lipke, C.; Schattenberg, A.V.M.B.; Willershausen, B.; Ernst, C.P.


    PURPOSE: To investigate the shortest exposure time of different light emitting diode (LED)-curing devices for different resin composites in a clinically relevant laboratory model. METHODS: Nine LED curing devices (Bluephase, Bluephase 16i, Bluephase G2, Bluephase 20i/Ivoclar Vivadent, DEMI/sds Kerr,

  2. Curing mechanism of alkaline phenolic resin with organic ester

    Institute of Scientific and Technical Information of China (English)

    Huang Renhe; Wang Yanmin; Zhang Baoping


    To study the curing mechanism of alkaline phenolic resin with organic ester, three esters were chosen to react with three systems - alkaline phenolic resin, potassium hydroxide aqueous solution containing phenol, and potassium hydroxide aqueous solution. The variations of pH, heat release and gel pH during the reactions were monitored and measured. Infrared spectroscopy (IR) and thermal gravity analysis (TG) techniques were used to characterize the curing reaction. It was found that organic ester is only partial y hydrolyzed and resin can be cured through organic ester hydrolysis process as wel as the reaction with redundant organic ester. The sequential curing mechanism of alkaline phenolic resin cured by organic ester was identified as fol ows: a portion of organic ester is firstly hydrolyzed owing to the effect of the strong alkaline; the gel is then formed after the pH decreases to about 10.8-10.88, meanwhile, the redundant organic ester (i.e. non-hydrolysis ester) starts the curing reaction with the resin. It has also been found that the curing rate depends on the hydrolysis velocity of organic ester. The faster the hydrolysis speed of the ester, the faster the curing rate of the resin.

  3. Development of various curing effect of nominal strength Geopolymer concrete

    Directory of Open Access Journals (Sweden)

    S. Kumaravel


    Full Text Available Geopolymer concrete is an innovative method and is produced by complete elimination of ordinary Portland cement byproduced in fly ash. This study on different condition of curing in geopolymer concrete suitable for curing at ambient and heat-cured condition of temperature will widen its application to concrete structures. Low lime fly ash is used as the base material, which is reacted by alkaline solution and additional use of ground granulated blast furnace slag. Workability of fresh concrete and compressive strength of geopolymer concrete was investigated. The curing effect of geopolymer concrete is steam, hot air and ambient cubes specimens are tested in different days. Results are compared for various curing and strength of concrete.


    Institute of Scientific and Technical Information of China (English)

    Jian-wen Bao; Ye Li; Xiang-yu Zhong; Xiang-bao Chen; Feng-mei Li


    The post-cure kinetics of electron beam (EB) curing of epoxy resin initiated by diaryiodinium was investigated.The post-cure reaction fits first order reaction kinetics. The reaction rate constant increases with increasing treatment temperature of post-cure. The reaction rate of post-cure is much lower than the rate of its reaction on electron beam treatment.

  5. 陶粒赤泥粉煤灰免烧砖性能研究%Research on properties of red mud fly ash from the burn exemption autoclaved brick

    Institute of Scientific and Technical Information of China (English)

    王敦强; 徐捷; 周国栋


    Based on the requirement of national energy conservation and environmental protection, we use the waste red mud and fly ash of Shandong Xinfa Aluminum and Electricity Group as the main raw material and with lime and cement as sharpened agent to produce red mud ceramsite fly ash from burn from autoclaved brick that is pressured molding by the pressure brick machine and natural curing. In order to make the industrialization production and substitute for clay brick, we make a quantitative analysis of the ratio of raw material and production process. Then, we get the reasonable ratio of raw materials and production process parameters, and discusse the influence of the ratio of raw material and production process parameters on the performance of the products. The results show; 1. When the composition is made up of 25% red mud, 18% fly ash, 45% ceramsite and 12% cement, brick products have the highest intensity; 2. When the composition is made up of 18% red mud, 21% fly ash, 50% ceramsite and 11% cement, the strength of the brick products meets the requirements, heat insulation performance is improved greatly and other physical properties also meet the requirement.%基于国家节能环保的要求,以山东信发铝电集团的废弃物赤泥、粉煤灰为主要原料,用石灰、水泥作为激化剂,经压砖机压制成型,自然养护来生产赤泥陶粒粉煤灰免烧免蒸压砖.为了使其工业化生产并能代替粘土砖,对原材料配比和生产工艺进行了定量分析,得出了合理的试验配方和生产工艺参数,探讨了原材料配比和生产工艺参数对砖制品性能的影响.结果表明:(1)当25%赤泥、18%粉煤灰、45%陶粒、12%水泥时,砖制品的强度最高.(2)当18%赤泥,21%粉煤灰,50%陶粒和11%水泥时,强度满足要求,保温性能大大提高,吸水率、冻融性和放射性等各方面物理特性符合要求.

  6. Technology status of autoclaved aerated concrete by utilizing mine tailings%利用矿山尾矿制备加气混凝土技术现状

    Institute of Scientific and Technical Information of China (English)

    罗立群; 舒伟


    根据发展循环经济和矿山清洁生产的开发思路,简述了矿山尾矿的产出和利用现状。针对尾矿堆存侵占土地、破坏生态环境、导致空气污染、易发生安全事故等危害,介绍了尾矿再选和大宗消纳等综合利用的两大途径。叙述了尾矿制备加气混凝土的技术特征,指出尾矿加气混凝土制品具有尾矿利用量大、节能降耗显著、保温隔热、质轻抗震、加工容易等综合优良性能,阐述了加气混凝土制备机理及其制品的性能表征,重点总结了利用铁尾矿、铜尾矿、黄金尾矿和其它矿山尾矿制备加气混凝土的技术现状。结合加气混凝土的生产和工程应用实际,提出尾矿制备加气混凝土应重点注意矿山尾矿粒度对建材原料的适应性、活化石灰的质量与原料中钙质矿物的影响、注重科学试验和人才培训、加强尾矿建材制品的力学性能研究等实际问题。%According to development idea on circular economy and clean production to exploiting mineral resources ,the present output and harm of producing on mine tailings were briefly reviewed .Tailings stockpiling have terrible effects on the expropriation of land ,the destruction of the ecological environment , causing air pollution ,easy to produce the safety accidents ,etc .Therefore ,two approaches of comprehensive utilization on tailings ,i .e .,recycling of useful components and bulk of consumption were introduced .On the basis of descriptions on the technical features of tailings ,related properties of autoclaved aerated concrete (AAC) with large amount of tailings utilization ,significant in energy saving ,thermal insulation ,light weight ,easy processing ,aseismatic performance were indicated respectively ,The technical status of utilizing iron tailings ,copper tailings ,gold tailings and other mine tailings to produce autoclaved aerated concrete was summarized intensively after the preparation mechanism

  7. Variation of Resin Properties Through the Thickness of Cured Samples (United States)


    It is the purpose of this work to gain knowledge of the glassy materials used as matrices in composites and to study the homogeneity resulting from the curing process. An attempt is made to link the glass transition quantitatively with the presence of a given material. Expoxy resins containing various amounts of hardener (TGDDM/DDS system) were cured in a muffle furnace at 473 K for seven hours. The glass transition temperature, T sub g versus weight minus percent of hardener in the epoxy resin were measured. A limit was rapidly reached in T sub g at only two percent hardener. Thus, the glass transition of the fully cured epoxy-amine matrix seems not much different from the epoxide-epoxide cure. The T sub g versus cure-time for the epoxide-epoxide reaction was also studied. My 720 was cured by itself in an oil bath at 473 K for different lengths of time. The T sub g was found to increase exponentially with the cure time, and a maximum T sub g of about 450 K was reached after eleven hours. The reaction was found to be inhibited by running the sample under argon.

  8. Development of Geopolymer Concrete with Different Curing Conditions

    Directory of Open Access Journals (Sweden)

    M.F. Nuruddin Nuruddin


    Full Text Available Environmental issues resulted from cement production have become a major concern today. To develop a sustainable future it is encouraged to limit the use of this construction material that can affect the environment. Cement replacement material was proposed to partially replace cement portion in concrete. Geopolymer is a part of inorganic polymer material that has similar bonding function like cement in concrete. It consists of alkaline solutions and geological source material. Alkaline liquids used in this research are 8 M sodium hydroxide (NaOH solution and sodium silicate (Na2SiO3 solutions, while source materials are fly ash and microwave incinerated rice husk ash (MIRHA. Three different curing regimes, namely hot gunny curing, ambient curing, and external exposure curing, were applied to obtain suitable method that was suitable with cast in situ application. Geopolymer concrete samples were tested on their compressive strength and microstructure properties. It was found that external exposure curing had the highest compressive strength compared to other two curing methods. Scanning electron microscopy analysis also showed better improvement in interfacial transition zone for concrete sample with external exposure curing.

  9. Electron Beam Cured Epoxy Resin Composites for High Temperature Applications (United States)

    Janke, Christopher J.; Dorsey, George F.; Havens, Stephen J.; Lopata, Vincent J.; Meador, Michael A.


    Electron beam curing of Polymer Matrix Composites (PMC's) is a nonthermal, nonautoclave curing process that has been demonstrated to be a cost effective and advantageous alternative to conventional thermal curing. Advantages of electron beam curing include: reduced manufacturing costs; significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvement in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance the electron beam curing of PMC technology. Over the last several years a significant amount of effort within the CRADA has been devoted to the development and optimization of resin systems and PMCs that match the performance of thermal cured composites. This highly successful materials development effort has resulted in a board family of high performance, electron beam curable cationic epoxy resin systems possessing a wide range of excellent processing and property profiles. Hundreds of resin systems, both toughened and untoughened, offering unlimited formulation and processing flexibility have been developed and evaluated in the CRADA program.

  10. A 'cure' for Down syndrome: what do parents want? (United States)

    Inglis, A; Lohn, Z; Austin, J C; Hippman, C


    Recent advancements in molecular genetics raise the possibility that therapeutics or a 'cure' for Down syndrome (DS) may become available. However, there are no data regarding how parents of children with DS perceive the possibility of mitigating specific manifestations such as the intellectual disability (ID) associated with DS, or curing the condition entirely. To explore these issues, we distributed a questionnaire to members of the Lower Mainland Down Syndrome Society in British Columbia, Canada. Questionnaires were completed by 101 parents (response rate=41%). A majority (61%) viewed the possibility of reversing ID in DS positively, but only 41% said that they would 'cure' their child of DS if it were possible. Twenty-seven percent of respondents said they would not 'cure' their child, and 32% were unsure if they would 'cure' their child. The most commonly cited motivation for opting for a 'cure' was to increase their child's independence. However, parental attitudes' towards a 'cure' for DS were complex, affected by ethical issues, perceived societal values, and pragmatic factors such as the age of the individual and long-term care-giving burden. These findings could be used by healthcare professionals supporting families who include a member with DS and to direct future research.

  11. Composite depth of cure using four polymerization techniques

    Directory of Open Access Journals (Sweden)

    Ericson Janolio de Camargo


    Full Text Available The light-curing technique is relevant to reduce the degree of polymerization shrinkage, improving clinical and esthetic success of composite resin restorations. OBJECTIVE: To evaluate in vitro the effect of four light-curing techniques on depth of cure of a composite resin. MATERIAL AND METHODS: Ten specimens of a composite resin were made in cylindrical cavities prepared in PVC plates (3.0 X 7.0 mm for each light-curing technique. Four photoactivation methods were investigated: stepped, ramped, pulse-delay and traditional. Specimens were longitudinally sectioned and polished for microhardness measurements (kg/mm², which were made at 0.1, 1.0, 2.0 and 4.0 mm from the irradiated surface. Data were subjected to ANOVA and Tukey's test. RESULTS: The effect of factors studied (curing method and distance from the surface and the interaction of these factors was statistically significant (p<0.05. The traditional method of cure provided higher microhardness values (69.6 ± 2.5 than the stepped (63.5 ± 3.1 and pulsed (63.9 ± 3.2 methods at all depths evaluated, but it did not differ from the ramped method (66.7± 4.4 at 0.1 and 1.0 mm of depth. CONCLUSION: All techniques employed provided satisfactory cure of the composite resin up to the depth of 2.0 mm from the irradiated surface.

  12. Development of a resin curing model for UV nanoimprint. (United States)

    Lee, Jin Woo; Cho, Dong-Woo


    UV nanoimprint lithography uses UV light as an energy source. It is performed at room temperature and low pressure, and has its own merits as compared to thermal nanoimprint. In this paper, a measurement system was developed to measure the degree of resin curing in UV nanoimprint to improve our understanding of the resin solidification phenomenon. A curing model was then established based on the measurement results. The measurement system measured the degree of cure in real time and was composed of a Fourier transform infrared spectroscopy system, a UV light source, and an optical guide. Also, new UV-curable resins that had low viscosity values were developed for the UV nanoimprint process, and imprint tests using these resins were performed successfully. The curing model considered the UV irradiation time, power, and curing temperature, which are important parameters in the UV nanoimprint process. The degree of cure had an exponential relation to UV irradiation time, power, and temperature; thus, the curing model was expressed as an exponential function of the UV irradiation time, power, and temperature. The developed model was verified for various UV-curable resins.

  13. Escherichia coli K-12 survives anaerobic exposure at pH 2 without RpoS, Gad, or hydrogenases, but shows sensitivity to autoclaved broth products.

    Directory of Open Access Journals (Sweden)

    Daniel P Riggins

    Full Text Available Escherichia coli and other enteric bacteria survive exposure to extreme acid (pH 2 or lower in gastric fluid. Aerated cultures survive via regulons expressing glutamate decarboxylase (Gad, activated by RpoS, cyclopropane fatty acid synthase (Cfa and others. But extreme-acid survival is rarely tested under low oxygen, a condition found in the stomach and the intestinal tract. We observed survival of E. coli K-12 W3110 at pH 1.2-pH 2.0, conducting all manipulations (overnight culture at pH 5.5, extreme-acid exposure, dilution and plating in a glove box excluding oxygen (10% H2, 5% CO2, balance N2. With dissolved O2 concentrations maintained below 6 µM, survival at pH 2 required Cfa but did not require GadC, RpoS, or hydrogenases. Extreme-acid survival in broth (containing tryptone and yeast extract was diminished in media that had been autoclaved compared to media that had been filtered. The effect of autoclaved media on extreme-acid survival was most pronounced when oxygen was excluded. Exposure to H2O2 during extreme-acid treatment increased the death rate slightly for W3110 and to a greater extent for the rpoS deletion strain. Survival at pH 2 was increased in strains lacking the anaerobic regulator fnr. During anaerobic growth at pH 5.5, strains deleted for fnr showed enhanced transcription of acid-survival genes gadB, cfa, and hdeA, as well as catalase (katE. We show that E. coli cultured under oxygen exclusion (<6 µM O2 requires mechanisms different from those of aerated cultures. Extreme acid survival is more sensitive to autoclave products under oxygen exclusion.

  14. Changes on degree of conversion of dual-cure luting light-cured with blue LED (United States)

    Bandéca, M. C.; El-Mowafy, O.; Saade, E. G.; Rastelli, A. N. S.; Bagnato, V. S.; Porto-Neto, S. T.


    The indirect adhesive procedures constitute recently a substantial portion of contemporary esthetic restorative treatments. The resin cements have been used to bond tooth substrate and restorative materials. Due to recently introduction of the self-bonding resin luting cement based on a new monomer, filler and initiation technology has become important to study the degree of conversion of these new materials. In the present work the polymerization reaction and the filler content of dual-cured dental resin cements were studied by means of infra-red spectroscopy (FT-IR) and thermogravimetry (TG). Twenty specimens were made in a metallic mold (8 mm diameter × 1 mm thick) from each of 2 cements, Panavia® F2.0 (Kuraray) and RelyX™ Unicem Applicap (3M/ESPE). Each specimen was cured with blue LED with power density of 500 mW/cm2 for 30 s. Immediately after curing, 24 and 48 h, and 7 days DC was determined. For each time interval 5 specimens were pulverized, pressed with KBr and analyzed with FT-IR. The TG measurements were performed in Netzsch TG 209 under oxygen atmosphere and heating rate of 10°C/min from 25 to 700°C. A two-way ANOVA showed DC (%) mean values statistically significance differences between two cements ( p 0.05). The Relx-Y™ Unicem mean values were significantly higher than Panavia® F 2.0. The degree of conversion means values increasing with the storage time and the filler content showed similar for both resin cements.

  15. Research on use of high calcium desulfurization ash in autoclaved brick%利用高钙固硫灰生产蒸压砖的研究

    Institute of Scientific and Technical Information of China (English)

    陈滨; 刘恒波; 万军


      The paper researches on the process of high calcium desulfurization ash autoclaved brick, and puts forward the ways to use the high calcium, high sulfur and low silicon of fly ash from the circulating fluidized bed boiler.%  对高钙固硫灰生产蒸压砖的生产工艺进行了研究,提出了重点解决循环流化床锅炉粉煤灰的高钙、高硫、低硅难题的有效途径

  16. Experimental observation of internal water curing of concrete

    DEFF Research Database (Denmark)

    Lura, Pietro; Jensen, Ole Mejlhede


    Internal water curing has a significant effect on concrete. In addition to affecting hydration and moisture distribution, it influences most concrete properties, such as strength, shrinkage, cracking, and durability. The following paper is an overview of experimental methods to study internal water...... curing of concrete and its consequences. The special techniques needed to study internal water curing are dealt with along with the consequences of this process. Examples of applications are given and new measuring techniques that may potentially be applied to this field are addressed....

  17. Chemical modification of L-glutamine to alpha-amino glutarimide on autoclaving facilitates Agrobacterium infection of host and non-host plants: A new use of a known compound

    Directory of Open Access Journals (Sweden)

    Das Pralay


    Full Text Available Abstract Background Accidental autoclaving of L-glutamine was found to facilitate the Agrobacterium infection of a non host plant like tea in an earlier study. In the present communication, we elucidate the structural changes in L-glutamine due to autoclaving and also confirm the role of heat transformed L-glutamine in Agrobacterium mediated genetic transformation of host/non host plants. Results When autoclaved at 121°C and 15 psi for 20 or 40 min, L-glutamine was structurally modified into 5-oxo proline and 3-amino glutarimide (α-amino glutarimide, respectively. Of the two autoclaved products, only α-amino glutarimide facilitated Agrobacterium infection of a number of resistant to susceptible plants. However, the compound did not have any vir gene inducing property. Conclusions We report a one pot autoclave process for the synthesis of 5-oxo proline and α-amino glutarimide from L-glutamine. Xenobiotic detoxifying property of α-amino glutarimide is also proposed.

  18. 基于CATIA的半实物仿真用液压釜的设计与研究%Design and research of autoclave based on CATIA for hardware-in-the-loop simulation

    Institute of Scientific and Technical Information of China (English)

    陈江; 赵文纯; 鞠海洪


    For the design and research of an autoclave for hardware-in-loop simulation, a design method for autoclave based on the CATIA virtual prototype technology was proposed. The 3D modeling was carried out by using CATIA. Then, the weakness of the autoclave was checked and optimized by using CATIA-Analysis in order to improve the safety and reliability of autoclave. Finally, an autoclave which can meet the design requirements was designed.%针对半实物仿真用液压釜进行了设计与研究.提出了基于CATIA虚拟样机技术的的液压釜设计方法,通过CATIA进行三维实体建模,并通过CATIA-Analysis对液压釜薄弱处进行枝核优化,用以提高液压釜使用运行的安全性和可靠性,最终设计出满足要求的液压釜.

  19. Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units. (United States)

    Bahrololoomi, Zahra; Soleimani, Ali Asghar; Jafari, Najmeh; Varkesh, Bentolhoda


    Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

  20. Measuring Vapors To Monitor the State of Cure of a Resin (United States)

    Cramer, Elliott; Perey, Daniel F.; Yost, William T.


    A proposed noninvasive method of monitoring the cure path and the state of cure of an epoxy or other resin involves measurement of the concentration( s) of one or more compound(s) in the vaporous effluent emitted during the curing process. The method is based on the following general ideas: (1) The concentrations of the effluent compounds in the vicinity of the curing resin are approximately proportional to the instantaneous rate of curing. (2) As curing proceeds at a given temperature, subsequent decreases in the concentrations are indicative of approaching completion of cure; that is, the lower are the concentrations, the more nearly complete is the cure.

  1. The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements. (United States)

    Souza-Junior, Eduardo José; Prieto, Lúcia Trazzi; Soares, Giulliana Panfiglio; Dias, Carlos Tadeu dos Santos; Aguiar, Flávio Henrique Baggio; Paulillo, Luís Alexandre Maffei Sartini


    The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37°C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p ≤ 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.

  2. Comparative Study of Alkali-Activated Fly Ash Manufactured Under Pulsed Microwave Curing and Thermal Oven Curing


    Shi, Shi; Bai, Yun; Li, H.; Xu, D. L.; Basheer, P. A. Muhammed


    This paper compares the alkali-activated fly ash (AAFA) manufactured with thermal oven curing and pulsed microwave curing methods. Fly ash activated by 8M NaOH solution at a liquid to solid ratio of 0.3 was cured by thermal oven at 85°C and domestic microwave oven, respectively. Apart from compressive strength test, the temperature profiles of AAFA samples were captured by thermal camera. Reaction products of AAFA were characterised with XRD, FTIR and TG/DTG, while the microstructure of AAFA ...

  3. Chemistry and technology of Cured and Smoked Meat Products

    Directory of Open Access Journals (Sweden)

    V. K. Mathur


    Full Text Available Recent developments in the chemistry and technology of cured and smoked meat products are reviewed. Various factors physical, chemical and microbiological affecting water holding capacity of cured meats and cured colour formation and its stability during storage are discussed. Methods of preparation of various types of cured and smoked meat products have been briefly described. Developments in the use of synthetic casings and skinless sausages have been mentioned. Smoke constituents, their role and physico-chemical aspects of mechanism and functions of smoking are discussed. Advancements in the methods of smoke generation, conventional smoking and some kilns, electrostatic smoking and smoking by use of liquid smokes have been described. Some of the methods of preparation of liquid smokes are also given.

  4. Cure monitoring using ultrasonic guided waves in wires (United States)

    Vogt, T.; Lowe, M.; Cawley, P.


    The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented.

  5. Curing of Epoxy Resin Induced by Femtosecond Laser Pulse

    Institute of Scientific and Technical Information of China (English)

    LI Yubin; ZHANG Zuoguang


    The possibility of curing of epoxy resin induced by femtosecond laser beam was explored through choosing different initiators . Absorption spectroscopy, infrared spectroscopy (IR), stereomicroscopy and scanning electron microscopy (SEM) were applied to analyze the structure of epoxy resin systems after irradiation with a femtosecond laser beam. The experimental results show that the epoxy resin systems containing diaryliodonium salts can be cured by irradiation of Jemtosecond laser pulse, while the systems containing benzoin can not be cured. It is found that diaryliodonium salts decompose under the irradiation of femtosecond laser pulse through multi ( two ) -photon absorption, initiating the ring-opening polymerization of epoxy resin. And the appearance of cured area has a sheet structure consisting of many tiny lamellar structures.


    The CURE electrocoagulation technology was demonstrated under the Superfund Innovative Technology Evaluation (SITE) program at the U.S. Department of Energy (DOE) Rocky Flats Environmental Technology Site (RFETS), where water from the solar evaporation ponds (SEPs) was contaminat...

  7. Cure monitoring using ultrasonic guided waves in wires. (United States)

    Vogt, T; Lowe, M; Cawley, P


    The possibility of using ultrasonic guided waves for monitoring the cure process of epoxy resins is investigated. The two techniques presented use a wire waveguide which is partly embedded in the resin. The first technique is based on the measurement of attenuation due to leakage of bulk waves into the resin surrounding the waveguide. The second technique measures the reflection of the guided wave that occurs at the point where the waveguide enters the resin. Both the attenuation and the reflection coefficient change significantly during cure, and the numerical methods to relate these to the material properties of the curing resin are presented in this paper. The results from the modeling are experimentally verified and show good agreement. The applicability of each testing method is discussed, and typical cure-monitoring curves are presented.

  8. Factors affecting dry-cured ham consumer acceptability. (United States)

    Morales, R; Guerrero, L; Aguiar, A P S; Guàrdia, M D; Gou, P


    The objectives of the present study were (1) to compare the relative importance of price, processing time, texture and intramuscular fat in purchase intention of dry-cured ham through conjoint analysis, (2) to evaluate the effect of dry-cured ham appearance on consumer expectations, and (3) to describe the consumer sensory preferences of dry-cured ham using external preference mapping. Texture and processing time influenced the consumer preferences in conjoint analysis. Red colour intensity, colour uniformity, external fat and white film presence/absence influenced consumer expectations. The consumer disliked hams with bitter and metallic flavour and with excessive saltiness and piquantness. Differences between expected and experienced acceptability were found, which indicates that the visual preference of consumers does not allow them to select a dry-cured ham that satisfies their sensory preferences of flavour and texture.

  9. The Prevention and Cure of Cervical Vertebra Disease

    Institute of Scientific and Technical Information of China (English)


    CERVICAL vertebra problems are common and usually occur in middleaged and elderly people, especially those who often bend over. The symptoms patients might encounter are dizziness, headache, neck and shoulder pain and numbness, and even viscera trouble. The following exercises are a simple and convenient way to prevent and cure cervical vertebra problems. If you continue doing the exercises, you can prevent and cure them. Here are the exercises step by step:

  10. Cure Characteristics of Tricyanate Ester High Temperature Composite Resins (PREPRINT) (United States)


    isothermal DSC data were analyzed via the Kissinger [17], Ozawa [18], and Friedman [19] methods, as described in the recent analysis of dicyanate ester...7 present the graphical analysis that underlies the Kissinger [17], Ozawa [18], and Friedman [19] methods, respectively, of non-isothermal DSC cure...where β is the heating rate and Tp the absolute temperature at the peak cure rate, is proportional to the activation energy. For the Ozawa method

  11. In-situ cure monitoring of epoxy resin systems


    Powell, Graham


    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. This thesis describes the work carried out at Brunel University to develop novel optical fibre sensors capable of monitoring the cure state of an epoxy/amine resin system. The sensors were of simple construction, consisting of an optical fibre from which the silicone cladding layer had been removed over a short length. This stripped length was embedded into the curing resin system. The sensor...

  12. Research on basic mechanical properties of autoclaved fly ash brick%蒸压粉煤灰砖基本力学性能研究

    Institute of Scientific and Technical Information of China (English)

    刘双龙; 闫欢欢


    按照《砌墙砖试验方法》(GB/T2542-2003)对蒸压粉煤灰砖进行砖的含水率、抗压强度、抗折强度试验。确定蒸压粉煤灰砖的基本力学指标,为编制辽宁省地方标准《蒸压粉煤灰砖建筑技术规范》提供试验依据。结果表明,蒸压粉煤灰砖含水率为2.96%,抗压强度为11.46MPa,抗折强度为1.68MPa,在实际工程上可替代普通烧结砖使用。%According to the GB/T 2542-2003 of masonry brick test method,the moisture content,compressive strength,transverse strength of the autoclaved fly ash brick are test.The results show that the autoclaved fly ash brick moisture content is 2.96 %,the compressive strength is 11.46 MPa,and the transverse strength is 1.68 MPa,so it can used as a substitute for the common fired brick in project.The mechanics index can provide a basis for the Liaoning standards of fly ash brick construction technical specifications.

  13. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel: Comparison of In- and Out-of-Autoclave Facesheet Configurations (United States)

    Pineda, Evan Jorge; Myers, David E.; Kosareo, Daniel N.; Zalewski, Bart F.; Kellas, Sotiris; Dixon, Genevieve D.; Krivanek, Thomas M.; Gyekenyesi, Thomas G.


    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10-m diameter barrel section of the Heavy Lift Launch Vehicle, were manufactured and tested under the NASA Composites for Exploration and the NASA Constellation Ares V programs. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.0 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: in-autoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3 ft. by 5 ft. panels were cut from the 1/16th barrel sections and tested under compressive loading. Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of each 3 ft. by 5 ft. panel. To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yielded good qualitative and quantitative predictions. Additionally, it was correctly predicted that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber angle misalignments, and three-dimensional effects on the compressive response of the panel.

  14. A pilot-scale steam autoclave system for treating municipal solid waste for recovery of renewable organic content: Operational results and energy usage. (United States)

    Holtman, Kevin M; Bozzi, David V; Franqui-Villanueva, Diana; Offeman, Richard D; Orts, William J


    A pilot-scale (1800 kg per batch capacity) autoclave used in this study reduces municipal solid waste to a debris contaminated pulp product that is efficiently separated into its renewable organic content and non-renewable organic content fractions using a rotary trommel screen. The renewable organic content can be recovered at nearly 90% efficiency and the trommel rejects are also much easier to sort for recovery. This study provides the evaluation of autoclave operation, including mass and energy balances for the purpose of integration into organic diversion systems. Several methods of cooking municipal solid waste were explored from indirect oil heating only, a combination of oil and direct steam during the same cooking cycle, and steam only. Gross energy requirements averaged 1290 kJ kg(-1) material in vessel, including the weight of free water and steam added during heating. On average, steam recovery can recoup 43% of the water added and 30% of the energy, supplying on average 40% of steam requirements for the next cook. Steam recycle from one vessel to the next can reduce gross energy requirements to an average of 790 kJ kg(-1).

  15. Microwave or autoclave treatments destroy the infectivity of infectious bronchitis virus and avian pneumovirus but allow detection by reverse transcriptase-polymerase chain reaction. (United States)

    Elhafi, G; Naylor, C J; Savage, C E; Jones, R C


    A method is described for enabling safe transit of denatured virus samples for polymerase chain reaction (PCR) identification without the risk of unwanted viable viruses. Cotton swabs dipped in avian infectious bronchitis virus (IBV) or avian pneumovirus (APV) were allowed to dry. Newcastle disease virus and avian influenza viruses were used as controls. Autoclaving and microwave treatment for as little as 20 sec destroyed the infectivity of all four viruses. However, both IBV and APV could be detected by reverse transcriptase (RT)-PCR after autoclaving and as long as 5 min microwave treatment (Newcastle disease virus and avian influenza viruses were not tested). Double microwave treatment of IBV and APV with an interval of 2 to 7 days between was tested. After the second treatment, RT-PCR products were readily detected in all samples. Swabs from the tracheas and cloacas of chicks infected with IBV shown to contain infectious virus were microwaved. Swabs from both sources were positive by RT-PCR. Microwave treatment appears to be a satisfactory method of inactivating virus while preserving nucleic acid for PCR identification.

  16. Clinical Application of Paper-plastic Package's Extension of Autoclave Pack%纸塑包装延长高压灭菌包的临床应用

    Institute of Scientific and Technical Information of China (English)



    目的:纸塑包装延长高压灭菌包的临床应用.方法:双层棉包布常规包装高压灭菌按要求存放7d,霉季5d,而纸塑包装可保存6个月.结果:纸塑包装大大延长无菌包的无菌时间.包装安全经济,可靠,并可预防院内感染.%Goal: clinical application of paper-plastic package’s extension of autoclave pack.Method: things regularly packed with double cotton and autoclaving can be stored for 7d, or 5d in mildew season; but thing packed with paper can be stored for 6 months.Result: paper pack greatly expands the asepsis time of sterility pack.The pack is safe and reliable, and can prevent infection in hospital.


    Directory of Open Access Journals (Sweden)

    Bedov Anatolij Ivanovich


    Full Text Available Relevant structural solutions, physical and mechanical characteristics, coefficients of thermal conductivity for exterior masonry walls made of autoclaved gas-concrete blocks are provided in the article. If a single-layer wall is under consideration, an autoclaved gas-concrete block is capable of performing the two principal functions of a shell structure, including the function of thermal protection and the bearing function. The functions are performed simultaneously. Therefore, the application of the above masonry material means the design development and erection of exterior walls of residential buildings noteworthy for their thermal efficiency. In the event of frameless structures, the height of the residential building in question may be up to 5 stories, while the use of a monolithic or a ready-made frame makes it possible to build high-rise buildings, and the number of stories is not limited in this case. If the average block density is equal to 400…500 kilograms per cubic meter, the designed wall thickness is to be equal to 400 mm. Its thermal resistance may be lower than the one set in the event of the per-element design of the thermal protection (Rreq = 3.41 м2 C/Watt, in Ufa, although it will meet the requirements of the applicable regulations if per-unit power consumption rate is considered.


    Institute of Scientific and Technical Information of China (English)

    GAO Tao; PENG Wei; YAO Chunyan


    Analytical simulation and corresponding proof-test are adopted to study the principle of the curing process of photopolymer resin diamond tools. The influence of the diamond as abrasives in photopolymer resin owing to the absorptivity of the diamond for the UV light on the photopolymer resin curing process is discussed. Based on the above, a kind of diamond tool-dicing blade is selected to analyze the curing process of photopolymer bond diamond tools. An analytical model of curing process is developed and a correlation curve between the depth of polymerization of the photopolymer resin diamond tools and the exposure time to represent the curing process of photopolymer bond dicing blade. A test is done to proof-test the validity of the analytical model and the correlation curve. The simulated data fit the experimental results, which demonstrates the analytical models and numerical algorithm are of high reliability. The analytical simulation method could possibly be used to optimize the curing cycle and improve the quality of the photopolymers resin bond diamond tools.

  19. Monitoring the Cure State of Thermosetting Resins by Ultrasound

    Directory of Open Access Journals (Sweden)

    Alfonso Maffezzoli


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

  20. Depth of cure of bulk-fill flowable composite resins. (United States)

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


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

  1. On autoclaved aerated concrete block wall and plaster layer anti-crack%浅谈蒸压加气混凝土砌块墙体及粉刷层防裂

    Institute of Scientific and Technical Information of China (English)



    According to the comparison on characteristics of the autoclaved aerated concrete block and traditional red brick, the author analyzes causes of wall crack quality common diseases, and provides corresponding control measures, so as to solve the crack problem of the autoclaved aerated concrete block wall and the plaster layer, thus promoting application of the autoclaved aerated concrete block.%通过比较蒸压加气混凝土砌块与传统红砖的特性,分析其墙体裂缝质量通病的原因,并提出相应的控制措施,以解决蒸压加气混凝土砌块墙体及粉刷层的开裂问题,从而推广蒸压加气混凝土砌块的应用.

  2. Optimization Study on Processing Conditions of Corn Resistant Starch by Autoclaving and Acid Hydrolysis Treatment%压热酸解法制备玉米抗性淀粉的工艺优化

    Institute of Scientific and Technical Information of China (English)

    冯铄涵; 阚建全


    The resistant starch was prepared with the High amylose corn starch by autoclaving-cooling cycles combined with acids hydrolysis treatment.The effects of concentration of starch solution,autoclaved temperature,autoclaved time and times of autoclaved-cooling cycles on the content of RS were studied in the autoclaved treatment.The type,concentration and treatment time of acids were also studied in the acid hydrolysis process.The results showed that the optimum conditions is: 30% starch solution was autoclaved at 125℃ for 45min,after repeated 2 times,0.15mol/L citric acid hydrolysised for 12h.The yield of resistant starch is up to 39.27%.%以高直链玉米淀粉为原料,研究压热-冷却循环结合酸解法制备抗性淀粉的最佳工艺条件。通过单因素实验和正交实验探讨了压热-冷却循环过程中淀粉溶液浓度、压热温度、压热时间、循环次数以及酸解处理过程中酸的种类、酸的浓度、酸解时间对抗性淀粉得率的影响。结果表明,在淀粉溶液浓度为30%、压热温度125℃、压热时间45min条件下,经过2次压热-冷却循环,然后0.15mol/L柠檬酸水解处理12h,在此条件下抗性淀粉得率可达39.27%。

  3. Degree of cure-dependent modelling for polymer curing processes at small-strain. Part I: consistent reformulation (United States)

    Hossain, M.; Steinmann, P.


    A physically-based small strain curing model has been developed and discussed in our previous contribution (Hossain et al. in Comput Mech 43:769-779, 2009a) which was extended later for finite strain elasticity and viscoelasticity including shrinkage in Hossain et al. (Comput Mech 44(5):621-630, 2009b) and in Hossain et al. (Comput Mech 46(3):363-375, 2010), respectively. The previously proposed constitutive models for curing processes are based on the temporal evolution of the material parameters, namely the shear modulus and the relaxation time (in the case of viscoelasticity). In the current paper, a thermodynamically consistent small strain constitutive model is formulated that is directly based on the degree of cure, a key parameter in the curing (reaction) kinetics. The new formulation is also in line with the earlier proposed hypoelastic approach. The curing process of polymers is a complex phenomenon involving a series of chemical reactions which transform a viscoelastic fluid into a viscoelastic solid during which the temperature, the chemistry and the mechanics are coupled. Part I of this work will deal with an isothermal viscoelastic formulation including shrinkage effects whereas the following Part II will give emphasis on the thermomechanical coupled approach. Some representative numerical examples conclude the paper and show the capability of the newly proposed constitutive formulation to capture major phenomena observed during the curing processes of polymers.

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

    Energy Technology Data Exchange (ETDEWEB)

    Corcione, C. Esposito; Striani, R.; Frigione, M., E-mail:


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


    Directory of Open Access Journals (Sweden)

    Dr. Lilibeth A. Roxas


    Full Text Available The potential of Native Chicken to be processed into palatable ham was conducted making use of Queen Pineapple (QP crude extract as one of the curing ingredients. Primarily, the main goal is to develop a protocol in the manufacture of processed native chicken ham and determine the organoleptic quality of native chicken ham product. The age of the bird and maturity of the fruit were considered for the best organoleptic quality of chicken ham. In this study, the combine injection and dry cure (CIDC method of the conventional formula was adopted. The desired amount of QP crude extract was first determined for the pump pickle. Curing salt was used for the control while different volume of pineapple crude extract was used in two treatments. The protocols for processing native chicken were developed using slaughter native chicken, and QP crude extract as curing ingredient for ham making. Color, flavor, juiciness and tenderness were among the desirable characteristics considered in this study. The sensory evaluation by trained panelists on QP-cured ham samples demonstrated comparable results. All the cooked meat samples were apparently acceptable to the sensory panel. The mean scores for flavor, juiciness and tenderness of meat samples have slight differences; however, they are not statistically significant. Indeed, native chicken can be processed into palatable ham with queen pineapple (Formosa variety extract that served as curing ingredient, flavor enhancer and tenderizer. Native Chicken QP-Cured ham is a commendable value-added product for both native chicken and queen pineapple by-products (butterball size.

  6. Influence of argon laser curing on resin bond strength. (United States)

    Hinoura, K; Miyazaki, M; Onose, H


    Light cured resin composites are usually cured with halogen lamps whose light output decreases with time and distance to the resin surface. This study compared bond strengths of resins to tooth structure cured with either an argon laser or a conventional halogen light. The enamel and dentin of bovine incisors were ground on the buccal surface with wet #600 grit SiC paper. A 4 x 2 mm mold was placed on the tooth surface and Scotchbond 2/Silux and Clearfil Photobond/Photo Clearfil A were placed into the molds and cured using a Quick Light or an argon laser for exposure times of 10, 20, and 30 seconds, and distances of 0.0, 0.5, 1.0, and 1.5 mm from the resin surface. The intensity of the Quick Light was measured as 510 mW/cm2 at 470 +/- 15 nm and the intensity of the argon laser was adjusted to 510 mW/cm2 before curing. Shear bond tests at a crosshead speed of 1.0 mm/min were performed after 24 hours of storage in water. The bond strengths obtained with the halogen lamp and the laser were not significantly different at the same exposure times and at 0.0 or 0.5 mm from the resin surface. The laser cured bond strengths did not decrease with increasing distance whereas there was a significant decrease in halogen bond strengths at distances greater than 0.5 mm for both resins. The use of the laser might provide a clinical advantage in cases where the curing light source cannot be brought into proximity to the surface of the resin.


    Energy Technology Data Exchange (ETDEWEB)

    Adu-Wusu, K; Paul Burket, P


    Wet Air Oxidation (WAO) is one of the two technologies being considered for the destruction of Tetraphenylborate (TPB) in Tank 48H. Batch bench-scale autoclave testing with radioactive (actual) Tank 48H waste is among the tests required in the WAO Technology Maturation Plan. The goal of the autoclave testing is to validate that the simulant being used for extensive WAO vendor testing adequately represents the Tank 48H waste. The test objective was to demonstrate comparable test results when running simulated waste and real waste under similar test conditions. Specifically: (1) Confirm the TPB destruction efficiency and rate (same reaction times) obtained from comparable simulant tests, (2) Determine the destruction efficiency of other organics including biphenyl, (3) Identify and quantify the reaction byproducts, and (4) Determine off-gas composition. Batch bench-scale stirred autoclave tests were conducted with simulated and actual Tank 48H wastes at SRNL. Experimental conditions were chosen based on continuous-flow pilot-scale simulant testing performed at Siemens Water Technologies Corporation (SWT) in Rothschild, Wisconsin. The following items were demonstrated as a result of this testing. (1) Tetraphenylborate was destroyed to below detection limits during the 1-hour reaction time at 280 C. Destruction efficiency of TPB was > 99.997%. (2) Other organics (TPB associated compounds), except biphenyl, were destroyed to below their respective detection limits. Biphenyl was partially destroyed in the process, mainly due to its propensity to reside in the vapor phase during the WAO reaction. Biphenyl is expected to be removed in the gas phase during the actual process, which is a continuous-flow system. (3) Reaction byproducts, remnants of MST, and the PUREX sludge, were characterized in this work. Radioactive species, such as Pu, Sr-90 and Cs-137 were quantified in the filtrate and slurry samples. Notably, Cs-137, boron and potassium were shown as soluble as a

  8. Photothermal radiometry monitoring of light curing in resins

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano-Arjona, M A [Applied Physics Department, Cinvestav-Unidad Merida, A.P. 73 Cordemex, Merida, 97310 (Mexico); Medina-Esquivel, R [Cinvestav-Unidad Queretaro, Libramiento Norponiente 2000 Fracc. Real de Juriquilla, CP 76230, Queretaro (Mexico); Alvarado-Gil, J J [Applied Physics Department, Cinvestav-Unidad Merida, A.P. 73 Cordemex, Merida, 97310 (Mexico)


    Real time measurement of thermal diffusivity during the evolution of the light curing process in dental resins is reported using photothermal radiometry. The curing is induced by a non-modulated blue light beam, and at the same time, a modulated red laser beam is sent onto the sample, generating a train of thermal waves that produce modulated infrared radiation. The monitoring of this radiation permits to follow the time evolution of the process. The methodology is applied to two different commercially available light curing resin-based composites. In all cases thermal diffusivity follows a first order kinetics with similar stabilization characteristic times. Analysis of this kinetics permits to exhibit the close relationship of increase in thermal diffusivity with the decrease in monomer concentration and extension of the polymerization in the resin, induced by the curing light. It is also shown that the configuration in which the resin is illuminated by the modulated laser can be the basis for the development of an in situ technique for the determination of the degree of curing.

  9. Caul and method for bonding and curing intricate composite structures (United States)

    Willden, Kurtis S. (Inventor); Goodno, Kenneth N. (Inventor)


    The invention disclosed here is a method for forming and curing an intricate structure of criss-crossing composite stringers and frames that are bonded to a skin panel. A structure constructed in accordance with the invention would be well-suited for use as a portion of an aircraft fuselage, a boat hull, or the like. The method is preferably practiced by applying uncured composite stringers to an uncured composite sheet panel. This is followed by placing cured frames crosswise over the stringers. The frames have openings at the locations where they intersect with the stringers which enables the frames to come into direct contact with the skin along most of their length. During the forming and curing process, the stringers are covered with a plurality of cauls, and the entire assembly of skin panel, stringers, frames and cauls is subjected to a vacuum bagging and curing process. The cauls serve to maintain both part shape and to control the flow of resin within the stringers as they are cured. Further, they probably eliminate the need for intermediate protective materials between the vacuum bag and the stringers.

  10. Thermal stability and curing kinetics of polycarbosilane fibers

    Institute of Scientific and Technical Information of China (English)


    Thermal stability and curing kinetics of polycarbosilane (PCS) fibers were studied by thermogravimetry (TG), Fourier transform infrared spectroscopy(FT-IR). Curing is an essential step in the preparation of SiC fibers and the properties of SiC fibers are affected greatly by curing conditions. TG measurement performed in air shows that mass gain starts at approximately 200℃ and PCS fibers are sensitive to oxygen. Curing with oxygen, which results in crosslinking on the surface, enabled PCS fibers to retain its shape during high-temperature pyrolysis. The curing of PCS fibers is oxidation of Si-H and Si-CH3, then Si-O-Si and Si-O-C bonds are formed. This is a first order reaction, with activation energy of 79.27 kJ/mol, and the pre-exponential factor is calculated as 3.07 × 106.The kinetics model was obtained and the experimental data of PCS fibers show good agreement with the kinetics model.

  11. Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages


    Xiao Zhang; Hongduo Zhao


    The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law,...

  12. Prediction of 28-day Compressive Strength of Concrete from Early Strength and Accelerated Curing Parameters


    T.R. Neelakantan; S. Ramasundaram; Shanmugavel, R.; R. Vinoth


    Predicting 28-day compressive strength of concrete is an important research task for many years. In this study, concrete specimens were cured in two phases, initially at room temperature for a maximum of 30 h and later at a higher temperature for accelerated curing for a maximum of 3 h. Using the early strength obtained after the two-phase curing and the curing parameters, regression equations were developed to predict the 28-day compressive strength. For the accelerated curing (higher temper...

  13. Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy

    Directory of Open Access Journals (Sweden)

    Sunint Singh


    Full Text Available Background: Conventional heat cure poly methyl methacrylate (PMMA is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy. Aim and Objectives: This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy. Materials and Methods: Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed. Results: Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable. Conclusion: Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by

  14. Influence of light curing units on failure of directcomposite restorations

    Directory of Open Access Journals (Sweden)

    Sameer Jadhav


    Full Text Available Light polymerizable tooth colored restorative materials are most widely preferred for advantages such as esthetics, improved physical properties and operator′s control over the working time. Since the introduction of these light polymerizable restorative materials, there has been a concern about the depth of appropriate cure throughout the restoration. Photopolymerization of the composite is of fundamental importance because adequate polymerization is a crucial factor for optimization of the physical and mechanical properties and clinical results of the composite material. Inadequate polymerization results in greater deterioration at the margins of the restoration, decreased bond strength between the tooth and the restoration, greater cytotoxicity, and reduced hardness. Therefore, the dentist must use a light curing unit that delivers adequate and sufficient energy to optimize composite polymerization. Varying light intensity affects the degree of conversion of monomer to polymer and depth of cure.


    Institute of Scientific and Technical Information of China (English)

    杨祖顺; 赵世文; 段智泉; 罗山; 杨萍; 田云屏


    目的 研究压力蒸汽灭菌器的灭菌延迟时间问题,为科学设定灭菌参数提供依据.方法 用动态温度监测仪监测方法,观察不同包装及装载方式下灭菌器内动态温度变化,确定灭菌器达到设定温度所需的延迟时间.结果灭菌器不同位置、不同载量的灭菌延迟时间为0 min;在空载条件下,以标准测试包和生物垃圾袋全开口方式包装,其灭菌延迟时间为0 min;以玻璃瓶、塑料瓶、生物垃圾袋半开口及生物垃圾袋密闭方式包装,其灭菌延迟时间分别为14 min、35 min、5 min和24 min.在满载复合因素影响下,最长的灭菌延迟时间可达48 min,且若灭菌参数仅设定为121℃、30 min,不能达到灭菌效果.结论 在进行灭菌参数设定时,应考虑压力蒸汽灭菌器的灭菌延迟时间,根据灭菌物品包装及装载方式,调整灭菌参数,否则可能造成灭菌操作失败.%Objective To study the sterilization delay time of autoclave in order to provide a basis for setting its sterilization parameters scientifically. Methods The dynamic temperature recorder monitoring method was utilized in the laboratory to monitor the interior dynamic change of temperature under different packing and loading modes, and to determine the sterilization delay time of autoclave. Results The sterilization delay time of autoclave was 0 min under different position or different load. Under no load condition, there was hardly sterilization delay time when temperature sensing probe were packed with standard test kits and full opening plastic bag. However, the sterilization delay time were 14 min, 35 min, 5 min and 24 min when parked with glass bottle, plastic bottle, half opening plastic bag or sealing plastic bag respectively. The longest sterilization delay time was up to 48 min under complex loading mode. And there was no sterilization efficacy if the sterilization parameters was set as 121 ℃ , 30min only. Conclusion The sterilization delay

  16. Pretreatment of poultry manure anaerobic-digested effluents by electrolysis, centrifugation and autoclaving process for Chlorella vulgaris growth and pollutants removal. (United States)

    Wang, Mengzi; Wu, Yu; Li, Baoming; Dong, Renjie; Lu, Haifeng; Zhou, Hongde; Cao, Wei


    Different pretreatments (electrolysis, centrifugation and autoclaving) coupled with Chlorella vulgaris biological system was used for the treatment of poultry manure anaerobic-digested effluents. The pretreated effluents were used as the growth medium for algal cultivation. The pollutant removal efficiencies of the combined treatments were determined. Electrochemical pretreatment can efficiently remove the ammonia (NH4+), total phosphorus (TP), total organic carbon (TOC), total carbon (TC), turbidity and bacteria in the digested effluents. About 100.0% NH4+, turbidity and bacteria, 97.6% TP, 81.5% TOC and 96.6% inorganic carbon were removed by 5-h electrochemical treatment. The maximal algal biomass accumulation (0.53 g L(-1)) was obtained from culture in the effluents pretreated with 2-h electrolysis. The pollutants removal amounts by the combination of electrolysis and biological treatment were much higher than the other combinations.

  17. Pretreatment of banana agricultural waste for bio-ethanol production: individual and interactive effects of acid and alkali pretreatments with autoclaving, microwave heating and ultrasonication. (United States)

    Gabhane, Jagdish; William, S P M Prince; Gadhe, Abhijit; Rath, Ritika; Vaidya, Atul Narayan; Wate, Satish


    Banana agricultural waste is one of the potential lignocellulosic substrates which are mostly un-utilized but sufficiently available in many parts of the world. In the present study, suitability of banana waste for biofuel production with respect to pretreatment and reducing sugar yield was assessed. The effectiveness of both acid and alkali pretreatments along with autoclaving, microwave heating and ultrasonication on different morphological parts of banana (BMPs) was studied. The data were statistically analyzed using ANOVA and numerical point prediction tool of MINITAB RELEASE 14. Accordingly, the optimum cumulative conditions for maximum recovery of reducing sugar through acid pretreatment are: leaf (LF) as the substrate with 25 min of reaction time and 180°C of reaction temperature using microwave. Whereas, the optimum conditions for alkaline pretreatments are: pith (PH) as the substrate with 51 min of reaction time and 50°C of reaction temperature using ultrasonication (US).

  18. Cleavage of catalytic ally grown carbon nanofibers into hydrophilic segments by oxidation in a mixture of concentrated HNO3-H2SO4 in an autoclave

    Institute of Scientific and Technical Information of China (English)

    TENG Li-hua; WANG Zhi-jiang; TANG Tian-di


    The catalytically grown carbon nanofibers were treated by a mixture of concentrated nitric aid and sulfuric aid in an autoclave at temperature 333,363 and 423 K.It was found that the samples treated at 363 K and 423 K were still well dispersed in water 15 hours later,indicating that carbon nanofibers can be made hydrophilicy.It was also found that the dispersion was destroyed when the pH value was lowered by adding acid.The results are significant when the carbon nanofibers are used as enhancing component in polymer composite material because several hundreds of nm are perfect size and the hydrophilicity controls the dispersion of CNFs in the polymer media.It is concluded that the amount of the oxygen-containing groups on the surface and the hydrophilicity of the carbon nanofibers can be controlled by the treatment temperature,and that the carbon nanofibers can be cleaved into uniform segments.

  19. Iron atoms redistribution in oxide films of Zr-Fe, Zr-Fe-Cu alloys during corrosion in autoclave at 350°C (United States)

    Filippov, V.; Bateev, A.


    The data on changes of iron atoms state in the oxide films of binary Zr-1.24 mas.%Fe and ternary Zr-1.39 mas.%Fe-0.60 mas.%Cu zirconium alloys are obtained. Alloys are subjected to corrosion tests under autoclave conditions at 350°C temperature in a steam-water environment under pressure p = 16.8 MPa. In initial specimens of the alloys the iron atoms are in the form of intermetallic compounds. In oxide films the decomposition of intermetallic compounds and formation of new compounds occurs with structural phase distortion. In the oxide films metallic the metallic iron particles α-Fe, iron oxide in the form of hematite α-Fe2O3, solid solutions of iron ions in ZrO2 are formed. The phase composition of the oxide films depends on the alloy composition and changes during the growth process of the oxide film.

  20. Efetividade de um protocolo de reprocessamento na esterilização de canetas de alta-rotação em autoclave gravitacional


    Alvarenga, Camila Fonseca; Reis, Cleomenes; Tipple,Anaclara Ferreira Veiga; Paiva,Enilza Maria Mendonça de; Sasamoto,Sandra Aragão de Almeida


    v.13,n.3,p.560--565,jul./set. 2011. Canetas odontológicas de alta-rotação são instrumentos de grande uso na prática clínica, com descontaminação polêmica, por apresentar complexo funcionamento. Estudo microbiológico, realizado no Serviço Odontológico da Universidade Federal de Goiás, teve como objetivo avaliar a efetividade do reprocessamento de canetas odontológicas de alta-rotação em autoclave gravitacional, seguindo um protocolo. Observados os aspectos éticos, os dados foram obtidos por...

  1. Pilot scale test on autoclaved brick production by semi-dry desulfurization by-products%半干法脱硫灰生产蒸压砖中试试验研究

    Institute of Scientific and Technical Information of China (English)

    刘松涛; 陈传敏; 赵毅; 卢林; 王涛; 杨艳芬


    The semi-dry desulfurization by-products are difficult to be utilized. Pilot scale study on the production technology of autoclaved brick which was mixed with semi-dry desulfurization by-products, slag and quicklime. The results show that autoclaved brick mixed with 50% semi-dry desulfurization ash and 10% quicklime dosage can meet the mechanical properties of MU20 strength grade. The mineral, such as hydrated calcium silicate, hydrated calcium aluminate and hydration sulphoaluminate, formed in autoclaved process can strengthen the strength of autoclaved brick.%为了解决半干法脱硫灰难以利用的问题,用脱硫灰、炉渣和CaO进行了蒸压砖生产的中试试验研究.研究表明:生产强度等级为MU20的脱硫灰蒸压砖,脱硫灰的掺量可控制在50%左右,CaO的掺量控制在10%左右.蒸压过程中形成的水化硅酸钙、水化铝酸钙和水化硫铝酸钙等矿物有利于增强蒸压砖强度.

  2. Analysis on non-autoclave pipe pile concrete raw material and maintenance system%免压蒸管桩混凝土原材料及养护制度分析

    Institute of Scientific and Technical Information of China (English)



    Combining with non-autoclave pipe pile concrete research status,starting from two aspects of raw material selection and maintenance system,the paper explores quality control measures of non-autoclave pipe pile concrete,analyzes the economy of non-autoclave pipe pile,and finally points out that:it not only reduces pipe pile producing energy consumption,but also improves pipe pile concrete durability through applying non-autoclave maintenance technology.%结合免压蒸管桩混凝土的研究现状,从原材料选用与养护制度两方面,探讨了免压蒸管桩混凝土的质量控制措施,并分析了免压蒸管桩的经济性,指出采用免压蒸养护生产工艺,既降低了管桩的生产能耗,又提高了管桩混凝土的耐久性。

  3. 环氧丙烷装置皂化电石渣处理方案%Feasibility scheme of epoxy propane saponification calcium carbide slag produce autoclaved fly ash brick

    Institute of Scientific and Technical Information of China (English)

    林盛海; 吴学亮


    本文介绍了皂化废电石渣用于生产蒸压粉煤灰砖的可行性。%The feasibility scheme of epoxy propane saponification Calcium carbide slag produce autoclaved fly ash brick was introduced.

  4. Application of a new type of electric appliance control mechanical safety interlock protection device in autoclaves%新型蒸压釜电器控制机械安全联锁保护装置

    Institute of Scientific and Technical Information of China (English)

    苏旭明; 李建华


    Autoclaves are widely used in industrial production. As a quick opening type pressure vessel, the safety interlock device is not perfect, which affects the safe operation of the autoclave. According to practical use, com⁃bines autoclaved reactor operating conditions, this paper introduces a electrical control mechanical safety interlock protection device which improves the autoclave safety coefficient, and prolongs service life of the interlock protec⁃tion device.%蒸压釜在工业生产中得到了广泛的使用,作为快开门式压力容器,安全联锁装置不完善,会对蒸压釜的安全运行造成影响。根据现场实际使用情况,结合蒸压釜的工作条件,介绍了一种电器控制机械安全联锁装置,提高了蒸压釜安全运行系数,也延长了联锁保护装置的使用寿命。

  5. Temperature and curing time affect composite sorption and solubility

    Directory of Open Access Journals (Sweden)

    Fabrício Luscino Alves de Castro


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

  6. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel. Part 2; 6-Ply In-Autoclave Facesheets (United States)

    Pineda, Evan J.; Meyers, David E.; Kosareo, Daniel N.; Zalewski, Bart F.; Dixon, Genevieve D.


    Four honeycomb sandwich panel types, representing 1/16th arc segments of a 10-m diameter barrel section of the Heavy Lift Launch Vehicle (HLLV), were manufactured and tested under the NASA Composites for Exploration program and the NASA Constellation Ares V program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: in-autoclave IM7/977-3 and out-of-autoclave T40-800b/5320-1. Smaller 3- by 5-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center (LaRC). Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of each 3- by 5-ft panel. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panels composed of 6-ply, IM7/977-3 facesheets (referred to as Panels B-1 and B-2). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear models yield good qualitative and quantitative predictions. Additionally, it was correctly predicted that the panel would fail in buckling prior to failing in strength. Furthermore, several imperfection studies were performed to investigate the influence of geometric imperfections, fiber angle misalignments, and three-dimensional (3-D) effects on the compressive response of the panel.

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

    Directory of Open Access Journals (Sweden)

    Jovičić Mirjana C.


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

  8. Grey Disorder in Field Flue—Cured Tobacco

    Institute of Scientific and Technical Information of China (English)



    A field study was carried out on the grey disorder in flue-cured tobacco( Nicotiana tabacum L.) leaves.The results showed that low Eh and high available Fe content in the soils were responsible for the grey tobacco and dead roots.Grey disorder leaves produced low quality lamina,which was low in N,nicotine,reduced sugar and K contents,In this study,soil available Mn and leaf Mn contents were in a relatively low level and should not be an important factor in the occurrence of grey disorder in flue-cured tobacco.

  9. Magnetoactive elastomeric composites: Cure, tensile, electrical and magnetic properties

    Indian Academy of Sciences (India)

    K Sasikumar; G Suresh; K A Thomas; Reji John; V Natarajan; T Mukundan; R M R Vishnubhatla


    Magnetically active elastomer materials were prepared by incorporating nickel powder in synthetic elastomeric matrices, polychloroprene and nitrile rubber. Cure characteristics, mechanical, electrical and magnetic properties were experimentally determined for different volume fractions of magnetoactive filler. The cure time decreases sharply for initial filler loading and the decrease is marginal for additional loading of filler. The tensile strength and modulus at 100% strain was found to increase with increase in the volume fraction of nickel due to reinforcement action. The magnetic impedance and a.c. conductivity are found to increase with increase in volume fraction of nickel as well as frequency.

  10. Realtime 3D stress measurement in curing epoxy packaging

    DEFF Research Database (Denmark)

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


    This paper presents a novel method to characterize stress in microsystem packaging. A circular p-type piezoresistor is implemented on a (001) silicon chip. We use the circular stress sensor to determine the packaging induced stress in a polystyrene tube filled with epoxy. The epoxy curing process...... is monitored by stress measurements. From the stress measurements we conclude that the epoxy cures in 8 hours at room temperature. We find the difference in in-plane normal stresses to be sigmaxx-sigmayy=6.7 MPa and (sigmaxx+sigmayy-0.4sigmazz)=232 MPa....

  11. Preliminary toxicological study of Sylgard 184 curing agent

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.M.; London, J.E.; Drake, G.A.; Thomas, R.G.


    The acute oral LD/sub 50//sup 30/ values for mice and rats receiving Sylgard 184 curing agent were greater than 5 g/kg. According to classical guidelines, the compound would be considered slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit demonstrated the compound to be mildly irritating. Eye irritation studies, also in the rabbit, showed that Sylgard 184 curing agent was a mild but transitory irritant. The sensitization study in guinea pigs did not show the resin to be deleterious.

  12. Emergent Cure Chemistry in the Development of Aerospace Materials (United States)


    R4 R3-SHR3-S-CH2-CH2-R4Product Anti-Markovnikov • Thiol-ene chemistry is a hybrid of free radical and condensation chemistry . It combines the speed...Charts 3. DATES COVERED (From - To) March 2015-March 2015 4. TITLE AND SUBTITLE Emergent cure chemistry in the development of aerospace materials...cure chemistry in the development of aerospace materials Joseph M. Mabry, Ph.D. Air Force Research Laboratory (661) 275-5857

  13. Cure Monitoring and Control with Combined Dielectric/Temperature Probes. (United States)


    DGEBA with expressions include an additional menthane diamine at 90*C were used parameter, 8, which accounts for to make the plots (the actual data...parameters to match Fig. 2 data. DGEBA cured with menthane diamine at Frequencies are 1,10,100 and 1000 Rz 900C. -5- ally with time (following the to slow down...mum. An example of such a result ure 2 shows plots correspondizg to is presented in Section 3.1 below. the model curves of Fig. 1 for DGEBA cured

  14. Effect of Autoclaved Schedule for Compressive Strength of Hematite Tailing Bricks%蒸压制度对赤铁矿尾矿蒸压砖强度的影响

    Institute of Scientific and Technical Information of China (English)

    赵云良; 张一敏; 陈铁军


    Effect of autoclaved schedule for compressive strength of hematite tailing-lime-yellow sand system was studied. The suitable autoclaved schedule was that rise time, autoclave pressure, autoclave time, and decompression time were 2.1 h, 1. 2 MPa, 6 h and 3. 5 h, respectively, when the quality ratio of hematite tailings: lime: yellow sands was equal to 70:15:15 and forming pressure was 20 MPa. The mechanism of Effect of autoclaved schedule for compressive strength was discussed by XRD and DSC. The results show that in the hydration reaction process, hydrogarnet is firstly generated, and then CSH( 1) and high-strength tobermorite under the condition of 1. 2 MPa autoclaved pressure. With autoclave continuing, tobermorite is gradated into relative low-strength xonotlite.%研究了蒸压制度对赤铁矿尾矿-石灰-黄沙体系蒸压砖抗压强度的影响,确定了原料中尾矿、石灰、黄沙的质量比为70∶15∶15,成型压力为20 MPa的砖坯的适宜蒸压制度为∶升压时间2.1h,蒸汽压力1.2 MPa,恒压时间6h,降压时间3.5h.利用XRD 、DSC对蒸压砖抗压强度形成机理进行了探讨,结果表明,赤铁矿尾矿-石灰-黄沙体系在1.2MPa蒸汽压力下首先生成了水石榴石,而后生成CSH(Ⅰ)凝胶和高强度的托勃莫来石,随着蒸压时间的延长,托勃莫来石逐渐转化成强度相对较低的硬硅钙石.

  15. RC-加气混凝土砌块组合墙的抗震性能%Seismic performance of composite walls of RC-autoclaved aerated concrete blocks

    Institute of Scientific and Technical Information of China (English)

    刘佩; 袁泉; 郭猛; 李鹏飞


    Three composite wall specimens of RC-autoclaved aerated concrete blocks were tested under cyclic lateral loading to investigate their seismic performance. The damage processes and failure characters of the composite wall specimens were presented. And the load-bearing capacity, hysteresis behavior, stiffness and ductility capacity of the composite wall specimens were investigated, which were compared with those of the ordinary wall of autoclaved aerated concrete blocks. Test results show that the presence of constructional columns and beams constrained the propagation of cracks in the autoclaved aerate concrete blocks. And then the brittle behavior of the autoclaved aerated concrete blocks is changed, and the mechanical performance of the autoclaved aerated concrete blocks is improved. Composite walls of RC-autoclaved aerated concrete blocks with reasonable forms possess good seismic performance, and research on the composite walls provides a basis for the application of walls of autoclaved aerated concrete blocks in multi-storey buildings.%为了解RC-加气混凝土砌块组合墙的抗震性能,进行3片不同构造形式的RC-加气混凝土砌块墙的水平低周反复荷载试验.介绍组合墙试件的破坏过程和破坏特点,重点研究3片试件的承载力、滞回曲线、刚度和延性性能,并与已有普通加气混凝土砌块墙试验数据进行对比分析.研究结果表明:构造柱和系梁限制砌块裂缝的产生和发展,改善砌块的脆性性质,提高砌块的力学性能;通过合理构造措施将钢筋混凝土与加气混凝土砌块结合在一起形成的组合承重墙,具有较好的抗震性能,为加气混凝土砌块墙在多层房屋结构中的应用提供基础.

  16. Effects of feeding high protein or conventional canola meal on dry cured and conventionally cured bacon. (United States)

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


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

  17. Volatile compounds of dry-cured Iberian ham as affected by the length of the curing process. (United States)

    Ruiz, J; Ventanas, J; Cava, R; Andrés, A; García, C


    Volatile compounds from 10 dry-cured Iberian hams ripened for two different processing times, a prolonged traditional one (600 days) and a shortened process (420 days), were analysed by purge and trap coupled to gas chromatography-mass spectroscopy. Eighty-three compounds were identified which agreed with the major classes found in other ham types. The amount of methyl branched alkanes was much higher than in other dry-cured ham types, probably due to the feeding regime. The percentages of 2- and 3-methylbutanal were higher (p<0.0001 and p<0.0003, respectively) in the longer aged hams, whereas the amounts of some compounds from lipid oxidation decreased from 420 to 600 days aging. In agreement with these observations, 600-day hams had higher scores for those odour and flavour traits usually considered to be positive attributes and lower scores for rancidity. A positive and significant correlation between 2-methyl butanal and cured flavour was found.

  18. 响应面法优化压热法制备莲子抗性淀粉工艺的研究%Optimization of the Autoclaving Process for Preparation Lotus Seeds Resistant Starch by Response Surface Methods

    Institute of Scientific and Technical Information of China (English)

    汪颖; 郑宝东; 张怡; 林雨菲; 李淑婷


    以莲子淀粉为原料,采用压热法制备莲子抗性淀粉,通过单因素试验,研究淀粉乳浓度、压热温度、压热时间和淀粉乳pH值4个因素对莲子抗性淀粉得率的影响.利用响应面法进行分析,得到莲子抗性淀粉制备的最佳工艺条件.结果表明,所得的方程达到显著水平,压热法制备莲子抗性淀粉的最佳工艺条件为:淀粉乳浓度30%,压热温度111℃,压热时间10 min,淀粉乳pH值为6~7.实际测得的莲子抗性淀粉得率为41.89%±1.23%,与理论预测值基本一致.%Lotus seed resistant starch was prepared by autoclaving. On the basis of single factor tests, the effect of starch concentration, autoclaving temperature, autoclaving time and pH value on the yield of lotus seeds resistant starch were studied. The conditions of preparing resistant starch were optimized with response surface methods. Results revealed that the model was significant, and the optimal conditions were as follows: starch concentration of 30%, autoclaving temperature of 111 °C, autoclaving time of 10 min, pH6~7. With these optimized conditions, the yield of lotus seeds resistant starch reached 41.89%±1.23%, the same as the prediction value in the model.

  19. 用于热压浸出工艺的高压釜装备研究及工程放大%Application of Autoclave in Pilot Plant Test in Pressure Leaching Process

    Institute of Scientific and Technical Information of China (English)

    段东平; 周娥; 陈思明; 夏光祥


      热压浸出是湿法冶金领域发展至今非常有推广前景的高效工艺,高压釜是该工艺的核心装备与关键技术。系统回顾了中国科学院过程工程研究所多年来利用热压浸出工艺处理难冶金银精矿、高铁闪锌矿、氧化铜矿及红土矿等的研究历程,从实验室小试—扩试—示范工程直至工业生产的途径,分别采用了管式高压釜、空气搅拌高压釜、钛复合板高压釜以及100 m3生产型高压釜,实现了这些难处理矿产资源的高效清洁利用。%The pressure leaching is a very efficient hydrometallurgy process with autoclave being the key equipment and technology.This paper systematically reviewed gold and silver concentrate,high iron sphalerite, copper oxide ore and Laterite were treated by pressure leaching from laboratory test,expanded test to the industrial production of the demonstration project in IPE.Respectively,in a tubular autoclave,air stirred autoclave,titanium autoclave and industrial autoclave of 100 m3,these refractory mineral resources were extracted efficiently and cleanly.

  20. Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin

    Directory of Open Access Journals (Sweden)

    Sheila Pestana Passos


    Full Text Available The aim of this study was to evaluate the effects of different light-curing units and resin cement curing types on the bond durability of a feldspathic ceramic bonded to dentin. The crowns of 40 human molars were sectioned, exposing the dentin. Forty ceramic blocks of VITA VM7 were produced according to the manufacturer's recommendations. The ceramic surface was etched with 10% hydrofluoric acid / 60s and silanized. The dentin was treated with 37% phosphoric acid / 15s, and the adhesive was applied. The ceramic blocks were divided and cemented to dentin according to resin cement / RC curing type (dual- and photo-cured, light-curing unit (halogen light / QTH and LED, and storage conditions (dry and storage / 150 days + 12,000 cycles / thermocycling. All blocks were stored in distilled water (37°C / 24h and sectioned (n = 10: G1 - QTH + RC Photo, G2 - QTH + RC Dual, G3 - LED + RC Photo, G4 - LED + RC Dual. Groups G5, G6, G7, and G8 were obtained exactly as G1 through G4, respectively, and then stored and thermocycled. Microtensile bond strength tests were performed (EMIC, and data were statistically analyzed by ANOVA and Tukey's test (5%. The bond strength values (MPa were: G1 - 12.95 (6.40ab; G2 - 12.02 (4.59ab; G3 - 13.09 (5.62ab; G4 - 15.96 (6.32a; G5 - 6.22 (5.90c; G6 - 9.48 (5.99bc; G7 - 12.78 (11.30ab; and G8 - 8.34 (5.98bc. The same superscript letters indicate no significant differences. Different light-curing units affected the bond strength between ceramic cemented to dentin when the photo-cured cement was used, and only after aging (LED > QTH. There was no difference between the effects of dual- and photo-cured resin-luting agents on the microtensile bond strength of the cement used in this study.

  1. Recidivism and Self-Cure of Smoking and Obesity (United States)

    Schacter, Stanley


    Data indicate that addictive-appetitive disorders such as obesity, opiate use, and cigarette smoking are not (as most professionals believe) markedly resistant to long-term modification. Studies of nontherapeutic populations indicate that long-term self-cures of smoking, obesity, and drug use are relatively common events. (Author/GC)

  2. 21 CFR 177.2400 - Perfluorocarbon cured elastomers. (United States)


    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only... generally recognized as safe (GRAS) in food or food packaging. (2) Substances used in accordance with a... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Perfluorocarbon cured elastomers. 177.2400...

  3. Hot embossing of microstructures on addition curing polydimethylsiloxane films

    DEFF Research Database (Denmark)

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


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

  4. Sodium nitrite: the "cure" for nitric oxide insufficiency. (United States)

    Parthasarathy, Deepa K; Bryan, Nathan S


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

  5. Gout: why is this curable disease so seldom cured?

    NARCIS (Netherlands)

    Doherty, M.; Jansen, T.L.Th.A.; Nuki, G.; Pascual, E.; Perez-Ruiz, F.; Punzi, L.; So, A.K.; Bardin, T.


    Gout is the most common inflammatory arthritis and one in which pathogenesis and risk factors are best understood. One of the treatment objectives in current guidelines is 'cure'. However, audits show that only a minority of patients with gout receive adequate advice and treatment. Suboptimal care a

  6. A consensus on criteria for cure of acromegaly

    NARCIS (Netherlands)

    A. Giustina (Andrea); P. Chanson (Philippe); M.D. Bronstein; A. Klibanski; S.W.J. Lamberts (Steven); F.F. Casanueva; P. Trainer; E. Ghigo (Ezio); K.K.Y. Ho; S. Melmed (Shlomo)


    textabstractObjective: The Acromegaly Consensus Group met in April 2009 to revisit the guidelines on criteria for cure as defined in 2000. Participants: Participants included 74 neurosurgeons and endocrinologists with extensive experience of treating acromegaly. Evidence/Consensus Process: Relevant

  7. Specific pretreatments reduce curing period of vanilla (Vanilla planifolia) beans. (United States)

    Sreedhar, R V; Roohie, K; Venkatachalam, L; Narayan, M S; Bhagyalakshmi, N


    With the aiming of reducing the curing period, effects of pretreatments on flavor formation in vanilla beans during accelerated curing at 38 degrees C for 40 days were studied. Moisture loss, change in texture, levels of flavoring compounds, and activities of relevant enzymes were compared among various pretreatments as well as the commercial sample. Use of naphthalene acetic acid (NAA; 5 mg/L) or Ethrel (1%) with blanching pretreatment resulted in 3-fold higher vanillin on the 10th day. Other flavoring compounds-vanillic acid, p-hydroxybenzoic acid, and p-hydroxybenzaldehyde-fluctuated greatly, showing no correlation with the pretreatments. Scarification of beans resulted in nearly 4- and 3.6-fold higher vanillin formations on the 10th day in NAA- and Ethrel-treated beans, respectively, as compared to control with a significant change in texture. When activities of major relevant enzymes were followed, addition of NAA or Ethrel helped to retain higher levels of cellulase throughout the curing period and higher levels of beta-glucosidase on the 20th day that correlated with higher vanillin content during curing and subsequent periods. Peroxidase, being highest throughout, did not correlate with the change in levels of major flavoring compounds. The pretreatment methods of the present study may find importance for realizing higher flavor formation in a shorter period because the major quality parameters were found to be comparable to those of a commercial sample.

  8. Student Actor Ailments: Ten Ills and How To Cure Them. (United States)

    Bishop, Barbara Long


    Lists the top ten acting ailments often encountered in student actors, and offers advice to cure these ailments: the split personality, the beauty queen and the leading man, the comedian, the director in training, the moody one, the character-clueless, the loner, the mimic, the stage-frightened, and the opening night artist. (SR)

  9. Nutidig mental sundhedsfremme i et historisk Mind-Cure perspektiv

    DEFF Research Database (Denmark)

    Wistoft, Karen


    the tradition, while also retaining the limitations noted by James. Three examples of this are mindfulness, religious coping and learned optimism. This article discusses how James’s critique can challenge these current Mind-Cure methods. The point is that illness, suffering and mental disorder have...

  10. LED Curing Lights and Temperature Changes in Different Tooth Sites

    Directory of Open Access Journals (Sweden)

    E. Armellin


    Full Text Available Objectives. The aim of this in vitro study was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit. Methods. Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA, Wilcoxon test, Kruskal-Wallis test, and Pearson’s χ2. After ANOVA, the Bonferroni multiple comparison test was performed. Results. Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin was evaluated. Significance. Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure.

  11. Bacterial spoilage of meat and cured meat products

    NARCIS (Netherlands)

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


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

  12. Curing Reaction Kinetics of Epoxy Resin Using Dicyandiamide Modified by Aromatic Amines

    Institute of Scientific and Technical Information of China (English)

    CHEN Lianxi; TIAN Hua; LIU Quanwen; Wang Jun


    The curing reaction and reaction mechanism of epoxy resin E-44, for which aromatic amine modified dicyandiamide was used as a curing reagent, were investigated by means of differential scanning calorimetry (DSC). The results showed that the modified dicyandiamide had better curing characteristic than ummodified dicyandiamide for epoxy resin E-44, and the curing reaction could be carried out at moderate temperature. Apparent activation energy of the curing reaction was decreased appreciably from 123.829 kJ/mol to 61.550-64.405 kJ/mol, and reaction order was decreased from 0.941 to 0.896-0.900. Curing reaction mechanism also was discussed.

  13. Application conditions for ester cured alkaline phenolic resin sand

    Institute of Scientific and Technical Information of China (English)

    Ren-he Huang; Bao-ping Zhang; Yao-ji Tang


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

  14. Research on the Preparation and Performance of Non-autoclaved High-strength Pipe Pile Concrete with Metakaolin%掺偏高岭土免压蒸高强管桩混凝土的制备与性能研究

    Institute of Scientific and Technical Information of China (English)

    曾俊杰; 水中和; 王胜年; 陈伟; 李龙


    High-strength pipe pile concrete was prepared with the incorporation of metakaolin, slag and fly ash under steam curing condition at 80 ℃. The influence of admixtures on concrete performances such as compressive strength, chloride penetration resistance and frost resistance were investigated. Feature of concrete pore structure was characterized by MIP. The results showed that the compressive strength of the steam cured concrete was increased by the incorporation of metakaolin, slag and fly ash, while the chloride penetration resistance, frost resistance and pore structure were improved significantly. The compressive strength of non-autoclaved high-strength pipe pile concrete prepared in this study reached C80. Meanwhile, the chloride diffusion coefficients were less than 2. 0 ×10-12 m2/s, while the freezing and thawing resistance was more than 400 times.%以偏高岭土、矿粉、粉煤灰为主要矿物掺合料,采用80℃常压蒸汽养护工艺进行高强管桩混凝土制备,研究了偏高岭土、矿粉、粉煤灰复合掺合料对混凝土力学性能和抗渗、抗冻等耐久性的影响,并采用压汞法分析了混凝土孔结构特征.结果表明,复掺偏高岭土、矿粉和粉煤灰能提高蒸养混凝土抗压强度,改善混凝土抗渗性和抗冻性,优化混凝土孔结构,所制备的免压蒸高强管桩混凝土强度达到C80等级,氯离子扩散系数低于2.0×10-12 m2/s,抗冻融循环次数大于400次.

  15. Comparative study of optical fiber cure-monitoring methods (United States)

    Crosby, Peter A.; Powell, Graham R.; Fernando, Gerard F.; Waters, David N.; France, Chris M.; Spooncer, Ronald C.


    This paper reports on a comparative study undertaken for different types of optical fiber sensor developed to monitor the cure of an epoxy resin system. The optical fiber sensors used to monitor the cure process were based on transmission spectroscopy, evanescent wave spectroscopy and refractive index monitoring. The transmission sensor was prepared by aligning two optical fibers within a specially prepared sleeve with a gap between the optical fiber end-faces. During cure, resin from the specimen flowed into the gap between the optical fibers allowing transmission spectra of the resin to be obtained. The evanescent wave sensor was prepared by stripping the cladding from a high refractive index core optical fiber. The prepared sensor was embedded in the sample and attenuated total reflectance spectra recorded from the resin/core boundary. Refractive index monitoring was undertaken using a high refractive index core optical fiber which had a small portion of its cladding removed. The prepared sensor was embedded in the resin specimen and light from a single wavelength source was launched into the fiber. Changes in the guiding characteristics of the sensor due to refractive index changes at the resin/core boundary were used to monitor the progress of the cure reaction. The transmission and evanescent wave spectroscopy sensors were used to follow changes in characteristic near-infrared absorption bands of the resin over the range 1450 - 1700 nm during the cure reaction. Consequently these techniques required tunable wavelength sources covering specific wavelength ranges. However, the refractive index based sensor used a single wavelength source. Therefore the equipment costs for this type of sensor were considerably less. Additionally, the refractive index sensor did not require a single wavelength source at any particular wavelength and could be applied to any spectral region in which the optical fiber would transmit light. The advantages and disadvantages of these

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

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

    DEFF Research Database (Denmark)

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


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


    Institute of Scientific and Technical Information of China (English)


    The curing process of chemical reacton between flexible unsaturated polymer resin and diphenylmethane bismaleimides which have been chain-prolonged by diaminodiphenylmethane is presented, also the kinetics parameters and curing technology are investigated.

  19. Experimental study on shear property of autoclaved fly ash brick masonry in Xinjiang region%新疆地区蒸压粉煤灰实心砖砌体抗剪性能试验研究

    Institute of Scientific and Technical Information of China (English)

    袁康; 陈燕华; 常新军; 何志军


    Autoclaved fly ash brick is classified as one new wall material to replace fired brick, promoting the shear property of autoclaved fly ash brick masonry is very important for improving the earthquake resistance and crack resistance of masonry structure.Because of fluting the surface of brick,the shear property of ribbed autoclaved fly ash brick masonry would be improved. In the paper,the shear property of ribbed autoclaved fly ash brick masonry, common autoclaved fly ash brick masonry and fired brick have been comparative studied,and the earthquake resistance and crack resistance measures have been discussed under the premise of relative standard citations,in order to provide the theoretical basis for autoclaved fly ash brick's further promotion and application in Xinjiang which is located in seismic high-incidence area, while have climate characteristics of dry climate, high annual temperature difference,high diurnal temperature difference.%蒸压粉煤灰砖属于可以替代烧结普通砖的新型墙体材料,提高蒸压粉煤灰砖砌体的抗剪性能是改善此类砌体结构抗震、抗裂能力的关键.带肋蒸压粉煤灰砖通过改善砖的外形,在砖的表面开槽形成肋状,可提高砖砌体的抗剪能力.本文对带肋蒸压粉煤灰砖砌体、普通蒸压粉煤灰砖砌体和烧结普通砖砌体的抗剪性能进行了比较研究,并结合相关规范条文探讨了带肋蒸压粉煤灰砖的有关抗震、抗裂措施,为蒸压粉煤灰砖在地处地震高发区同时具备气候干燥,年温差、日温差大的新疆地区推广应用提供理论依据.

  20. Finding a cure for HIV: will it ever be achievable?

    Directory of Open Access Journals (Sweden)

    Lewin Sharon R


    Full Text Available Abstract Combination antiretroviral therapy (cART has led to a major reduction in HIV-related mortality and morbidity. However, HIV still cannot be cured. With the absence of an effective prophylactic or therapeutic vaccine, increasing numbers of infected people, emerging new toxicities secondary to cART and the need for life-long treatment, there is now a real urgency to find a cure for HIV. There are currently multiple barriers to curing HIV. The most significant barrier is the establishment of a latent or "silent" infection in resting CD4+ T cells. In latent HIV infection, the virus is able to integrate into the host cell genome, but does not proceed to active replication. As a consequence, antiviral agents, as well as the immune system, are unable to eliminate these long-lived, latently infected cells. Reactivation of latently infected resting CD4+ T cells can then re-establish infection once cART is stopped. Other significant barriers to cure include residual viral replication in patients receiving cART, even when the virus is not detectable by conventional assays. In addition, HIV can be sequestered in anatomical reservoirs, such as the brain, gastrointestinal tract and genitourinary tract. Achieving either a functional cure (long-term control of HIV in the absence of cART or a sterilizing cure (elimination of all HIV-infected cells remains a major challenge. Several studies have now demonstrated that treatment intensification appears to have little impact on latent reservoirs. Some potential and promising approaches that may reduce the latent reservoir include very early initiation of cART and the use of agents that could potentially reverse latent infection. Agents that reverse latent infection will promote viral production; however, simultaneous administration of cART will prevent subsequent rounds of viral replication. Such drugs as histone deacetylase inhibitors, currently used and licensed for the treatment of some cancers, or

  1. Variable frequency microwave (VFM) curing, processing of thermoset prepreg laminates. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, F.L.


    The objective of this work was to investigate the beneficial effect of the variable frequency microwave (VFM) technology to cure thermosetting prepreg laminates. Further, it was to investigate the interrelationship and effect on the curing process of frequency, band width, and curing time with different types of laminates. Previous studies of microwave-assisted curing of neat resins (epoxy) and unidirectional glass and carbon fiber laminates with a fixed frequency of 2.45 GHz, have shown that a substantial reduction in the curing time was obtained. Results of this earlier work indicate that the microwave-assisted curing of multidirectional glass fiber laminates also show a substantial reduction of the required curing time. This may be explained by the penetration of microwave energy directly and throughout the laminate with enhancement of the kinetics of the chemical reaction. The fixed frequency microwave radiation of 2.45 GHz has been demonstrated to be a partially acceptable method to cure unidirectional carbon fiber laminates. Multidirectional carbon fiber/epoxy laminates demonstrate a lack of coupling during the curing process. A direct curing of these laminates was not possible by microwave radiation with the experimental approach used in agreement with previous work. In addition to this short coming, the unidirectional laminate samples cured with the fixed frequency are visually nonuniform. Localized areas of darker colors (burn, hot spots, overheating) are attributed to the formation of standing waves within the microwave cavity. For this reason, the laminates are subject to proper rotation while curing through fixed frequency. The present research indicates that variable frequency microwave technology is a sound and acceptable processing method to effectively cure uni-, bi- or multi-directional thermosetting glass fiber laminates. Also, this methodology will effectively cure unidirectional thermosetting carbon fiber laminates. For all these cases, this

  2. Cure Cycle Effect on High-Temperature Polymer Composite Structures Molded by VARTM


    Ahmed Khattab


    This paper presents an analytical and experimental investigation of cure cycle effect on carbon-fiber reinforced high-temperature polymer composite structures molded by vacuum assisted resin transfer molding (VARTM). The molded composite structure consists of AS4-8 harness carbon-fiber fabrics and a high-temperature polymer (Cycom 5250-4-RTM). Thermal and resin cure analysis is performed to model the cure cycle of the VARTM process. The temperature and cure variations with time are determined...

  3. Experimental investigation of interface curing stresses between PMMA and composite using digital speckle correlation method

    Institute of Scientific and Technical Information of China (English)


    This paper studies the interface curing stresses between polymethyl methacrylate (PMMA) and composite by means of digital speckle correlation method (DSCM).A new method by combining DSCM with the marker points is developed to measure the interface curing stresses,and the measurement principle is introduced.The interface curing stresses between PMMA and composite with different curing bonding conditions are measured and analyzed,this indicates that the residual stress for furnace heating and furnace cooling ...

  4. Progress Toward HIV Eradication: Case Reports, Current Efforts, and the Challenges Associated with Cure. (United States)

    Martin, Alyssa R; Siliciano, Robert F


    An estimated 35 million people worldwide are infected with HIV, yet a widely applicable cure strategy remains elusive. Recent case reports have suggested that curing HIV infection is possible, renewing excitement about research efforts. We describe those cases and discuss their relevance to the global HIV epidemic. We also review ongoing cure strategies that are transitioning from the lab to the clinic, and the assays and clinical assessments that can be used to evaluate cure interventions.

  5. Implications of prioritizing HIV cure: new momentum to overcome old challenges in HIV


    Tucker, JD; Gilbertson, A; Lo, YR; Vitória, M


    Background Curing HIV is a new strategic priority for several major AIDS organizations. In step with this new priority, HIV cure research and related programs are advancing in low, middle, and high-income country settings. This HIV cure momentum may influence existing HIV programs and research priorities. Discussion Despite the early stage of ongoing HIV cure efforts, these changes have directly influenced HIV research funding priorities, pilot programs, and HIV messaging. The building moment...

  6. Study of catalytic effect of ammonium molybdate on the bisphthalonitrile resins curing reaction with aromatic amine

    Institute of Scientific and Technical Information of China (English)

    Wen Ting Li; Fang Zuo; Kun Jia; Xiao Bo Liu


    A kind of catalyst, ammonium molybdate was developed in this paper to promote the curing reaction of bisphthalonitrile resins with aromatic amine as curing agent, and the catalytic effect was studied by differential scanning calorimetry (DSC), rheometric measurements and thermogravimetric analysis (TGA). The results indicated that the catalyst could improve the curing rate and increase the curing degree, which could be regulated by the content of the catalyst used in the reaction.

  7. Ionizing radiation post-curing of objects produced by stereolithography and other methods (United States)

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


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

  8. Influence of Cure Shrinkage on Process-Induced Stress and Deformation in Thick Thermosetting Composites (United States)


    unidirectional composite micromechanics model The constituent fiber properties (constant), the resin properties and chemical shrinkage (cure dependent...during cure. Changes in the resin properties directly influence the mechanical properties in the composite, and chemical shrinkage represents a...xA (5) The expansion coefficients, otL and or, are based on the micromechanics model utilizing constant fiber properties. cure dependent resin

  9. Curing lights for orthodontic bonding: A systematic review and meta-analysis

    NARCIS (Netherlands)

    Fleming, P.S.; Eliades, T.; Katsaros, C.; Pandis, N.


    INTRODUCTION: Light cure of resin-based adhesives is the mainstay of orthodontic bonding. In recent years, alternatives to conventional halogen lights offering reduced curing time and the potential for lower attachment failure rates have emerged. The relative merits of curing lights in current use,

  10. Curing Behavior and Viscoelasticity of Dual-Curable Adhesives Based on High-Reactivity Azo Initiator (United States)

    Lee, Jong-Gyu; Shim, Gyu-Seong; Park, Ji-Won; Kim, Hyun-Joong; Moon, Sang-Eun; Kim, Young-Kwan; No, Dong-Hun; Kim, Jong-Hwan; Han, Kwan-Young


    We have investigated the curing behavior of dual-curable acrylic resin to solve problems associated with curing of adhesives in shaded areas during display manufacture. A low-temperature curing-type thermal initiator, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), with a 30°C half-life decomposition temperature was used in the investigation. Dual-curable adhesives were prepared according to the thermal initiator content and ultraviolet (UV) radiation dose. The effects of thermal initiator and UV irradiation on the curing behavior and viscoelasticity were investigated. Using Fourier-transform infrared spectroscopy and gel-fraction analysis, an evaluation was carried out to determine the degree of curing after dual UV/thermal curing. In addition, the real-time curing behavior was evaluated using thermogravimetric analysis, differential scanning calorimetry, and a UV/advanced rheometric expansion system. A lift-off test was carried out to verify the effects of dual curing on adhesion performance. Application of UV irradiation before thermal curing suppressed the thermal curing efficiency. Also, the network structure formed after dual curing with low UV dose showed higher crosslinking density. Therefore, the thermal initiator radical effectively influenced uncured areas with low curing temperature and initiator content without causing problems in UV-curable zones.

  11. Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages

    Directory of Open Access Journals (Sweden)

    Xiao Zhang


    Full Text Available The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA. Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs.

  12. Gene Therapy to Cure HIV: Where to from Here? (United States)

    Johnston, Rowena


    A variety of approaches are being tested to cure HIV, but with the exception of the Berlin patient case, none has been successful. The Berlin patient, positive for both HIV and acute myeloid leukemia (AML), received two stem cell transplants from a donor homozygous for the CCR5delta32 mutation. In the 8 years since his second transplant, he has remained free of both HIV and AML. This case provides strong proof-of-principle that a cure for HIV is possible and might be achieved through gene therapy. Several technological barriers must be resolved and are discussed here, including the safe delivery of the intervention throughout the body of the infected person, increased efficiency of gene editing, and avoidance of resistance to the therapy. Delivery of a gene therapy intervention to HIV-infected people around the world will also be a considerable challenge.

  13. Monolithic growth of partly cured polydimethylsiloxane thin film layers

    DEFF Research Database (Denmark)

    Yu, Liyun; Skov, Anne Ladegaard


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

  14. Social desirability in personality inventories: symptoms, diagnosis and prescribed cure. (United States)

    Bäckström, Martin; Björklund, Fredrik


    An analysis of social desirability in personality assessment is presented. Starting with the symptoms, Study 1 showed that mean ratings of graded personality items are moderately to strongly linearly related to social desirability (Self Deception, Impression formation, and the first Principal Component), suggesting that item popularity may be a useful heuristic tool for identifying items which elicit socially desirable responding. We diagnose the cause of socially desirable responding as an interaction between the evaluative content of the item and enhancement motivation in the rater. Study 2 introduced a possible cure; evaluative neutralization of items. To test the feasibility of the method lay psychometricians (undergraduates) reformulated existing personality test items according to written instructions. The new items were indeed lower in social desirability while essentially retaining the five factor structure and reliability of the inventory. We conclude that although neutralization is no miracle cure, it is simple and has beneficial effects.

  15. Properties of Cement Mortar with Phosphogpysum under Steam Curing Condition

    Directory of Open Access Journals (Sweden)

    Kyoungju Mun


    Full Text Available The purpose of this study is to utilize waste PG as an admixture for concrete products cured by steam. For the study, waste PG was classified into 4 forms (dehydrate, β-hemihydrate, III-anhydrite, and II-anhydrite, which were calcined at various temperatures. Also, various admixtures were prepared with PG, fly-ash (FA, and granulated blast-furnace slag (BFS. The basic properties of cement mortars containing these admixtures were analyzed and examined through X-ray diffraction, scanning electron microscopy, compressive strength, and acid corrosion resistance. According to the results, cement mortars made with III-anhydrite of waste PG and BFS exhibited strength similar to that of cement mortars made with II-anhydrite. Therefore, III-anhydrite PG calcined at lower temperature can be used as a steam curing admixture for concrete second production.

  16. Epoxy-silicate nanocomposites: Cure monitoring and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Farzana [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada - NRC, Montreal, QC (Canada)]. E-mail:; Chen, Jihua [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada -NRC, Montreal, QC (Canada); Hojjati, Mehdi [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada - NRC, Montreal, QC (Canada)


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

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

    Directory of Open Access Journals (Sweden)

    Cemil Dizman


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

  18. PERBEDAAN KANDUNGAN SENYAWA VOLATIL DAUN SALAM (Eugenia polyantha Wight) PADA BEBERAPA PROSES CURING The Difference of Volatile Compounds of Bay Leaf (Eugenia polyantha Wight.) in Several Curing Processes



    The influence of curing process toward flavour substances of bay leaf has been conducted. Bay leaves were cured with three different time of process: 0, 2 and 4 days and extracted by simultaneous distillation-extraction using n- hexane. Flavour extract was evaporated by vacuum rotary evaporator and remained solvent was flushed with nitrogen gas. Flavour compounds of the bay leaf extract were analysed using GC-MS. The result showed that curing process affected the composition of bay leaf flavo...

  19. Compaction and Cure of Resin Film Infusion Prepregs


    Thompson, Joseph E.


    Gutowski et al.'s model has been employed to describe the cure and consolidation of prepregs used for resin film infusion. Resin kinetics, rheology, flow and fiber deformation are considered. Resin kinetics are simulated with an isothermal autocatalytic-1 type relation. The non-Newtonian viscosity of the Cytec™ 754 resin is represented with a gel type expression. The one dimensional flow of resin through a deformable, partially saturated porous medium is studied. A nonlinear partial...

  20. On the probability of cure for heavy-ion radiotherapy. (United States)

    Hanin, Leonid; Zaider, Marco


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

  1. Screening and cervical cancer cure: population based cohort study


    Andrae, B.; Andersson, T. M.-L.; Lambert, P C; Kemetli, L.; Silfverdal, L.; Strander, B.; Ryd, W.; Dillner, J.; Tornberg, S.; Sparen, P.


    Objective To determine whether detection of invasive cervical cancer by screening results in better prognosis or merely increases the lead time until death. Design Nationwide population based cohort study. Setting Sweden. Participants All 1230 women with cervical cancer diagnosed during 1999-2001 in Sweden prospectively followed up for an average of 8.5 years. Main outcome measures Cure proportions and five year relative survival ratios, stratified by screening history, mode of detection, age...

  2. Adherend Surface Effects on Epoxy Cure by NMR (United States)


    questions. 3 2. Summary of results. The structure and dynamics of the cure of the epoxy resin system based on the diglycidyl ether of bisphenol-A ( DGEBA ) is... DGEBA ), obtained from Dow Chemical Co. (der 332) was heated in the oven at temperature 160 OC until completely melted. The sample was cooled and at the...epoxy to ether conversion with the NMR analysis. (b) Results and Interpretation. The mixture of DGEBA with DDS was studied at temperature 1600C. The

  3. Wormholes as a cure for black hole singularities

    CERN Document Server

    Olmo, Gonzalo J; Sanchez-Puente, Antonio


    Using exactly solvable models, it is shown that black hole singularities in different electrically charged configurations can be cured. Our solutions describe black hole space-times with a wormhole giving structure to the otherwise point-like singularity. We show that geodesic completeness is satisfied despite the existence of curvature divergences at the wormhole throat. In some cases, physical observers can go through the wormhole and in other cases the throat lies at an infinite affine distance.

  4. Targeting the brain reservoirs: towards an HIV cure

    Directory of Open Access Journals (Sweden)

    Celine Marban


    Full Text Available One of the top research priorities of the international AIDS society by the action Towards an HIV Cure is the purge or the decrease of the pool of all latently infected cells. This strategy is based on reactivation of latently reservoirs (the shock followed by an intensifying Combination Antiretroviral Therapy (cART to kill them (the kill. The Central Nervous System (CNS has potential latently infected cells i.e. perivascular macrophages, microglial cells and astrocytes which will need to be eliminate. However the CNS has several characteristics that may preclude the achievement of a cure. In this review we discuss several limitations to the eradication of brain reservoirs and how we could circumvent these limitations by making it efforts in 4 directions: (i designing efficient Latency-Reversal Agents for CNS-cell types (ii improving cART by targeting HIV transcription (iii improving delivery of HIV drugs in the CNS and in the CNS-cell types (iv developing therapeutic immunization. As a prerequisite to these efforts we also believe that a better comprehension of molecular mechanisms involved in establishment and persistence of HIV latency in brain reservoirs are essential to design new molecules for strategies aiming to achieve a cure for instance the shock and kill strategy.

  5. [Can we cure autism? From outcome to intervention]. (United States)

    Alessandri, M; Thorp, D; Mundy, P; Tuchman, R F


    Outcome in autism is variable but with a significant trend toward a poor prognosis and despite reports that outcome in individuals with autism may be improving secondary to early intensive interventions there is still much to be learned about the natural history and the effects of intervention in autism spectrum disorders. While there may not be a known cure for autism, there are a number of viable treatment options available. The primary models of treatment are non pharmacological interventions that include intervention models such as applied behavior analysis and developmental and structured teaching. The role of pharmacological interventions is limited to treating specific symptoms that may be interfering with a child's ability to learn or function within a particular environment. The question of whether or not we can cure autism needs to be discussed in terms of the need to overcome the as of yet poorly understood fundamental disturbance in autism and the need to develop treatment protocols specifically targeting social deficits. At the present time, it is more appropriate to speak of our quest to understand autism than it is to speak of a cure.

  6. A 50-Year Journey to Cure Childhood Acute Lymphoblastic Leukemia (United States)

    Pui, Ching-Hon; Evans, William E.


    The 50th anniversary of Seminars in Hematology coincides with the 50th of St. Jude Children’s Research Hospital, and both milestones are inexorably linked to studies contributing to the cure of childhood acute lymphoblastic leukemia (ALL). We thought it fitting, therefore, to mark these events by traveling back in time to point out some of the achievements, institutions, study groups and individuals that have made cure of childhood ALL a reality. In many instances, progress was driven by new ideas, while in others it was driven by new experimental tools that allowed more precise assessment of the biology of leukemic blasts and their utility in selecting therapy. We also discuss a number of contemporary advances that point the way to exciting future directions. Whatever pathways are taken, a clear challenge will be to use emerging genome-based or immunologic-based treatment options in ways that will enhance, rather than duplicate or compromise, recent gains in outcome with classic cytotoxic chemotherapy. The theme of this journey serves as a reminder of the chief ingredient of any research directed to a catastrophic disease such as ALL. It is the audacity of a small group of investigators who confronted a childhood cancer with the goal of cure, not palliation, as their mindset. PMID:23953334


    Directory of Open Access Journals (Sweden)

    Jaroslava Budinski-Simendić


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

  8. The electron beam cure of epoxy paste adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.D. [Air Force Advanced Composites Program office, McClellan AFB, CA (United States); Janke, C.J. [Oak Ridge National Lab., TN (United States). Oak Ridge Centers for Manufacturing Technology; Lopata, V.J. [Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada). Whiteshell Labs.


    Recently developed epoxy paste adhesives were electron beam cured and experimentally explored to determine their suitability for use in an aerospace-quality aircraft component. There were two major goals for this program. The first was to determine whether the electron beam-curable past adhesives were capable of meeting the requirements of the US Air Force T-38 supersonic jet trainer composite windshield frame. The T-38 windshield frame`s arch is currently manufactured by bonding thin stainless steel plies using an aerospace-grade thermally-cured epoxy film adhesive. The second goal was to develop the lowest cost hand layup and debulk process that could be used to produce laminated steel plies with acceptable properties. The laminate properties examined to determine adhesive suitability include laminate mechanical and physical properties at room, adhesive tack, out-time capability, and the debulk requirements needed to achieve these properties. Eighteen past adhesives and four scrim cloths were experimentally examined using this criteria. One paste adhesive was found to have suitable characteristics in each of these categories and was later chosen for the manufacture of the T-38 windshield frame. This experimental study shows that by using low-cost debulk and layup processes, the electron beam-cured past adhesive mechanical and physical properties meet the specifications of the T-38 composite windshield frame.

  9. Persistent Comorbidities in Cushing’s Syndrome after Endocrine Cure

    Directory of Open Access Journals (Sweden)

    Eugenia Resmini


    Full Text Available It was assumed that resolution of hypercortisolism in Cushing syndrome (CS was followed by normalization of morbidity; however, in the last decade evidence is accumulating that patients with cured CS still have increased morbidity and mortality after the biochemical control of hypercortisolism. Patients with CS have an increased cardiovascular and metabolic risk and persistent accumulation of central fat, with an unfavorable adipokine profile, not only during the active phase of the disease but also long after biochemical remission. Clinical management should be particularly careful in identifying global cardiovascular risk, as a primary goal during the followup of these patients, aimed at improving global vascular morbidity. Moreover bone mass is reduced not only due to the endogenous hypercortisolism but also due to duration and dose of exogenous glucocorticoid (GC replacement therapy after surgery. Thus, therapy in operated patients with inhibition of the hypothalamic-pituitary-adrenal axis should be reduced to the lowest dose and duration possible. Specific treatments should be considered in patients with decreased bone mass, aimed at reducing the increased fracture incidence. Finally, cognitive and health related quality of life impairments, described in active disease, are still abnormal after endocrine cure. Thus, residual morbidity persists in cured CS, suggesting irreversibility of GC-induced phenomena, typical of chronic hypercortisolism.

  10. Microwaves energy in curing process of water glass molding sands

    Directory of Open Access Journals (Sweden)

    Granat K.


    Full Text Available This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO2 process (identical sands have also been tested for comparison after CO2 blowing process and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO2 process.

  11. Dataset of producing and curing concrete using domestic treated wastewater. (United States)

    Asadollahfardi, Gholamreza; Delnavaz, Mohammad; Rashnoiee, Vahid; Fazeli, Alireza; Gonabadi, Navid


    We tested the setting time of cement, slump and compressive and tensile strength of 54 triplicate cubic samples and 9 cylindrical samples of concrete with and without a Super plasticizer admixture. We produced concrete samples made with drinking water and treated domestic wastewater containing 300, 400 kg/m(3) of cement before chlorination and then cured concrete samples made with drinking water and treated wastewater. Second, concrete samples made with 350 kg/m(3) of cement with a Superplasticizer admixture made with drinking water and treated wastewater and then cured with treated wastewater. The compressive strength of all the concrete samples made with treated wastewater had a high coefficient of determination with the control concrete samples. A 28-day tensile strength of all the samples was 96-100% of the tensile strength of the control samples and the setting time was reduced by 30 min which was consistent with a ASTMC191 standard. All samples produced and cured with treated waste water did not have a significant effect on water absorption, slump and surface electrical resistivity tests. However, compressive strength at 21 days of concrete samples using 300 kg/m(3) of cement in rapid freezing and thawing conditions was about 11% lower than concrete samples made with drinking water.

  12. 变电站蒸压粉煤灰砖砌体围墙裂缝分析与防治%Analysis and Prevention of Substation of Autoclaved Fly Ash Brick Masonry Wall Cracks

    Institute of Scientific and Technical Information of China (English)



    本文结合变电站工程实际,分析了变电站工程蒸压粉煤灰砖砌体清水围墙裂缝产生的原因,从蒸压粉煤灰砖的生产、构造设计及砌筑施工等几个方面提出了防治措施。%Combining with the actual substation engineering, Analyzed the causes of transformer substation project of autoclaved fly ash brick masonry wall cracks in water, Puts forward the prevention measures from the aspects of production, structure design and masonry construction of autoclaved fly ash brick.

  13. Buckling Testing and Analysis of Honeycomb Sandwich Panel Arc Segments of a Full-Scale Fairing Barrel. Part 3; 8-ply Out-of-Autoclave Facesheets (United States)

    Pineda, Evan J.; Myers, David E.; Kosareo, Daniel N.; Kellas, Sotiris


    Four honeycomb sandwich panels, representing 1/16th arc segments of a 10 m diameter barrel section of the heavy lift launch vehicle, were manufactured under the NASA Composites for Exploration program and the NASA Constellation Ares V program. Two configurations were chosen for the panels: 6-ply facesheets with 1.125 in. honeycomb core and 8-ply facesheets with 1.000 in. honeycomb core. Additionally, two separate carbon fiber/epoxy material systems were chosen for the facesheets: inautoclave IM7/977-3 and out-of-autoclave T40-800B/5320-1. Smaller 3- by 5-ft panels were cut from the 1/16th barrel sections. These panels were tested under compressive loading at the NASA Langley Research Center. Furthermore, linear eigenvalue and geometrically nonlinear finite element analyses were performed to predict the compressive response of the 3- by 5-ft panels. This manuscript summarizes the experimental and analytical modeling efforts pertaining to the panel composed of 8-ply, T40-800B/5320-1 facesheets (referred to as Panel C). To improve the robustness of the geometrically nonlinear finite element model, measured surface imperfections were included in the geometry of the model. Both the linear and nonlinear, two-dimensional (2-D) and three-dimensional (3-D), models yield good qualitative and quantitative predictions. Additionally, it was predicted correctly that the panel would fail in buckling prior to failing in strength.

  14. Comparison of autoclave, microwave, IR and UV-C stabilization of whole wheat flour branny fractions upon the nutritional properties of whole wheat bread. (United States)

    Demir, Mustafa Kürşat; Elgün, Adem


    In this study, whole wheat bread (WWB) prepared by whole wheat flour (WWF) which its branny fraction (35 ± 1% w/w whole flour) previously was stabilized with different processes. Branny fractions obtained by milling of two different Bezostaja-1 wheat samples (medium and high strong) at 65 ± 1% wheat flour extraction ratio. These fractions were stabilized using autoclave (AU), microwave (MW), infrared (IR) and ultraviolet-C (UV-C) methods. Then, WWF obtained by remixing of stabilized branny fraction (35 ± 1% w/w) and wheat flour (65 ± 1% w/w) of same wheat samples. Following this process, WWB was made from WWF. WWB were analyzed to determine their nutritional properties as crude protein, in vitro protein digestibility (IVPD), phytic acid content, total and HCl-extractable mineral concentrations, total phenolic content (TPC), antioxidant activity and total dietary fiber (TDF). While IVPD, TPC and antioxidant activity of WWB increased together with all stabilization methods, a significant (P < 0.05) loss was observed on phytic acid content of the WWB. Especially, UV-C and IR treatments had positive effects on TPC and antioxidant activity. AU and MW stabilization methods increased total mineral and HCl-extractable minerals of WWB. As a result of this study, all stabilization processes had an improving effect on nutritional characteristic of WWB.

  15. Energy filtering transmission electron microscopy immunocytochemistry and antigen retrieval of surface layer proteins from Tannerella forsythensis using microwave or autoclave heating with citraconic anhydride. (United States)

    Moriguchi, K; Mitamura, Y; Iwami, J; Hasegawa, Y; Higuchi, N; Murakami, Y; Maeda, H; Yoshimura, F; Nakamura, H; Ohno, N


    Tannerella forsythensis (Bacteroides forsythus), an anaerobic Gram-negative species of bacteria that plays a role in the progression of periodontal disease, has a unique bacterial protein profile. It is characterized by two unique protein bands with molecular weights of more than 200 kDa. It also is known to have a typical surface layer (S-layer) consisting of regularly arrayed subunits outside the outer membrane. We examined the relationship between high molecular weight proteins and the S-layer using electron microscopic immunolabeling with chemical fixation and an antigen retrieval procedure consisting of heating in a microwave oven or autoclave with citraconic anhydride. Immunogold particles were localized clearly at the outermost cell surface. We also used energy-filtering transmission electron microscopy (EFTEM) to visualize 3, 3'-diaminobenzidine tetrahydrochloride (DAB) reaction products after microwave antigen retrieval with 1% citraconic anhydride. The three-window method for electron spectroscopic images (ESI) of nitrogen by the EFTEM reflected the presence of moieties demonstrated by the DAB reaction with horseradish peroxidase (HRP)-conjugated secondary antibodies instead of immunogold particles. The mapping patterns of net nitrogen were restricted to the outermost cell surface.

  16. Research on autoclaved reaction activities of Si/Al -based industrial residues%硅铝质工业废弃物蒸压反应活性研究

    Institute of Scientific and Technical Information of China (English)



    Mass fractions of active SiO2 and A12O3 ,and infrared spectrum (IR) were used to analyze the autoclaved reaction activities of Si/Al - based industrial residues, such as fly ash and coal dust slag etc. Results showed that autoclaved reaction activities of Si/Al - based industrial residues had an evident relationship with the mass fractions of active SiO2 and A12O3 ,and Si - O stretching vibration frequency about 1 100 cm-1 in strong absorption region of IR,that is the more mass fractions of active SiO2 and Al2 O3, and the lower Si-O stretching vibration frequency about 1 100 cm -1 in strong absorption region of IR, the stronger autoclaved reaction activities and the higher compressive strength of autoclaved products.%通过测定活性二氧化硅、氧化铝含量及红外光谱分析等方法研究粉煤灰、煤粉炉渣等硅铝质工业废弃物的蒸压反应活性.结果表明,硅铝质工业废弃物的蒸压反应活性与其活性二氧化硅、氧化铝含量及红外光谱1 100 cm-1附近强吸收区的Si-O伸缩振动频率存在明显的对应关系,即活性二氧化硅、氧化铝含量越高,红外光谱1 100 cm-1附近强吸收区的Si-O伸缩振动频率越低,蒸压反应活性越强,蒸压制晶强度越高.

  17. 环境温度对蒸压粉煤灰砖混合料消化的影响%Effect of environmental temperature on slaking of autoclaved fly ash brick mixture

    Institute of Scientific and Technical Information of China (English)



      The paper analyzes the effect of environmental temperature on slaking of autoclaved fly ash brick mixture, and the relationship between mixture and environmental temperature.%  分析了蒸压粉煤灰砖影响混合料消化的因素,分析了混合料与环境温度的关系,并对某企业存在的问题给出了解决办法。

  18. KOMPOSISI KIMIA DAN KRISTALINITAS TEPUNG PISANG TERMODIFIKASI SECARA FERMENTASI SPONTAN DAN SIKLUS PEMANASAN BERTEKANAN-PENDINGINAN (Chemical Composition and Crystallinity of Modified Banana Flour by Spontaneous Fermentation and Autoclaving-Cooling Cycle

    Directory of Open Access Journals (Sweden)

    Nurhayati Nurhayati


    (39,13 – 42,68% bk dibandingkan dengan yang satu siklus (29,34 – 35,93% bk. Proses pemanasan bertekananpendinginan menurunkan kristalinitas tepung pisang dari 18,74-20,08% menjadi 6,98-9,52%. Difraksi sinar X menunjukkan granula pati pisang adalah granula tipe C yang merupakan campuran dari granula tipe A dan tipe B. Kata kunci: Tepung pisang termodifikasi, fermentasi spontan, autoclaving-cooling cycles

  19. Effect of base monomer's refractive index on curing depth and polymerization conversion of photo-cured resin composites. (United States)

    Fujita, Kou; Nishiyama, Norihiro; Nemoto, Kimiya; Okada, Tamami; Ikemi, Takuji


    In this study, we examined the effect of the transmitted amount of visible light through a resin composite on the curing depth and polymerization conversion. Transmitted amount of visible light was strongly dependent on the magnitude of refractive index difference that existed between the resin and silica filler. More specifically, the differences arose from the type of base monomer used. The transmitted amount of visible light exhibited a good correlation with the curing depth and Knoop hardness ratio of the bottom surface against the top surface of the resin composite. To improve the polymerization conversion of the cavity floor, it is important to reduce the refractive index difference that exists between the base resin and silica filler.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Takashi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Takeda, Satoe; Shiraishi, Katsutoshi


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

  1. Study on preparation of autoclaved brick by Yellow River silt and fly ash added waste papermaking liquor%利用造纸黑液和粉煤灰-泥砂制备蒸压砖的研究

    Institute of Scientific and Technical Information of China (English)

    张新爱; 关润伶


    以粉煤灰、黄河泥砂为主要原料,炉渣为骨料,石灰、石膏为激发剂,用造纸黑液代替水做拌和液制备黄河泥砂-粉煤灰蒸压砖。结果表明,造纸黑液代水制备蒸压砖是可行的,制备的蒸压砖可以达到JC 239-2001《粉煤灰砖》规定的MU25级的质量要求。%Autoclaved brick is prepared by fly ash and Yellow River silt as main materials, waste papermaking liquor as mixing liquid. The results show that it is feasible to make autoclaved brick by waste papermaking liquor as mixing liquid. The autoclaved brick meets the demand of MU25 grade in JC 239-2001 (fly ash bricks) standard.

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

    Directory of Open Access Journals (Sweden)

    Tanvir Manzur


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

  3. Energy saving estimation on radiation process. Electron beam curing of paint

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Hideaki (Nihon Parkerizing Co., Ltd., Tokyo); Maekawa, H.; Ito, Y.; Nishikawa, I.; Fujii, H.; Murata, K.


    When the quantity of paint used for industrial coating is assumed to be 420,000 tons, it is estimated that the area being coated is 2.8 billion m/sup 2/, the petroleum required for pretreatment steam, drying and baking is 1.68 million tons, and the required amount of energy saving is 120,000 tons per year in terms of petroleum. The authors examined how the adoption of electron beam curing for surface coating contributes to the energy saving. So far, it has been said that electron beam curing is more efficient than thermal or light curing in energy consumption, but the premise condition was not clear. The theoretical energy requirement for thermal curing, light curing and electron beam curing was calculated and compared. The comparison of the measured values was also performed. The amount of energy required for thermal curing, UV light curing and electron beam curing was roughly 100:10:1, and the cost of energy for them was 50:5:1. In spite of the large merit of electron beam curing, it has not spread as expected, because of the repayment cost of the facility and the cost of inert gas required for the process. Energy saving is brought about by electron beam curing, but the overall cost must be examined case by case.

  4. Effects of light curing method and resin composite composition on composite adaptation to the cavity wall. (United States)

    Yoshikawa, Takako; Morigami, Makoto; Sadr, Alireza; Tagami, Junji


    This study aimed to evaluate the effects of the light curing method and resin composite composition on marginal sealing and resin composite adaptation to the cavity wall. Cylindrical cavities were prepared on the buccal or lingual cervical regions. The teeth were restored using Clearfil Liner Bond 2V adhesive system and filled with Clearfil Photo Bright or Palfique Estelite resin composite. The resins were cured using the conventional or slow-start light curing method. After thermal cycling, the specimens were subjected to a dye penetration test. The slow-start curing method showed better resin composite adaptation to the cavity wall for both composites. Furthermore, the slow-start curing method resulted in significantly improved dentin marginal sealing compared with the conventional method for Clearfil Photo Bright. The light-cured resin composite, which exhibited increased contrast ratios duringpolymerization, seems to suggest high compensation for polymerization contraction stress when using the slow-start curing method.

  5. A cure shrinkage model for analyzing the stresses and strains in encapsulated assemblies (United States)

    Chambers, R. S.; Lagasse, R. R.; Guess, T. R.; Plazek, D. J.; Bero, C.

    Electrical component assemblies are encapsulated to provide delicate parts with voltage isolation and protection against damage caused by shock, vibration, and harsh atmospheric environments. During cure, thermosetting resins shrink and harden simultaneously. If the natural deformation of the resin is constrained by adhesion to the mold or to relatively stiff embedded components, cure shrinkage stresses are generated in the encapsulant. Subsequent cooling or thermal cycling produces additional stresses that are caused by the mismatches in thermal strains among the materials in the encapsulated assembly. Although cure shrinkage stresses frequently are neglected because they are considerably smaller than thermal stresses, cure shrinkage stresses can cause delamination or fractures in the encapsulant, since the partially cured resin is not as tough as the fully cured material. Cracks generated during cure can compromise performance (e.g., permit dielectric breakdown), degrade a component's protection, and grow under subsequent thermal cycling producing residual stresses that differ from those found in uncracked assemblies.

  6. A cure shrinkage model for analyzing the stresses and strains in encapsulated assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, R.S.; Lagasse, R.R.; Guess, T.R. [Sandia National Labs., Albuquerque, NM (United States); Plazek, D.J.; Bero, C. [Pittsburgh Univ., PA (United States). Dept. of Materials Science and Engineering


    Electrical component assemblies are encapsulated to provide delicate parts with voltage isolation and protection against damage caused by shock, vibration, and harsh atmospheric environments. During cure, thermosetting resins shrink and harden simultaneously. If the natural deformation of the resin is constrained by adhesion to the mold or to relatively stiff embedded components, cure shrinkage stresses are generated in the encapsulant. Subsequent cooling or thermal cycling produces additional stresses that are caused by the mismatches in thermal strains among the materials in the encapsulated assembly. Although cure shrinkage stresses frequently are neglected because they are considerably smaller than thermal stresses, cure shrinkage stresses can cause delamination or fractures in the encapsulant, since the partially cured resin is not as tough as the fully cured material. Cracks generated during cure can compromise performance (e. g., permit dielectric breakdown), degrade a component`s protection, and grow under subsequent thermal cycling producing residual stresses that differ from those found in uncracked assemblies. 3 refs., 11 figs.

  7. [Effects of silicon carbide on the cure depth, hardness and compressive strength of composite resin]. (United States)

    Wang, Ke; Lin, Yi'na; Liu, Xiaoqing


    The hardness, compressive strength and cure depth are important indices of the composite resin. This investigation was made with regard to the effects of silicon carbide on the cure depth, hardness and compressive strength of the light-curing composite resin. Different amounts of silicon carbide were added to the light-curing composite resin, which accounted for 0 wt%, 1 wt%, 0.6 wt%, 0.3 wt%, 0.1 wt%, 0.05 wt% and 0.005 wt% of the composite resin, respectively. The hardness, compressive strength and cure depth of the six afore-mentioned groups of composite resin were measured by the vernier caliper, the vickers hardness tester and the tensile strength of machine, respectively. The results showed that silicon carbide improved the hardness and compressive strength of the light-curing composite resin,when the concentration was 0.05 wt%. And the cure depth was close to that of control.

  8. An exponential chemorheological model for viscosity dependence on degree-of-cure of a polyfurfuryl alcohol resin during the post-gel curing stage

    DEFF Research Database (Denmark)

    Dominguez, J.C.; Oliet, M.; Alonso, María Virginia


    In the present study, the chemorheological behavior of a bio-based polyfurfuryl alcohol (PFA) resin has been determined by rheological isothermal tests at different curing temperatures for the post-gel curing stage of the resin, using three different amounts of catalyst (2, 4 and 6 wt %). Instead...

  9. The effects of halogen and light-emitting diode light curing on the depth of cure and surface microhardness of composite resins

    Directory of Open Access Journals (Sweden)

    Batu Can Yaman


    Full Text Available Aim : Light-emitting diode light curing units (LED LCUs have become more popular than halogen LCUs in routine dental restorative treatment. The aim of the study was to compare the effects of two conventional halogen (Hilux Plus and VIP and two LED (Elipar FreeLight 2 and Smart Lite light curing units on the depth of cure and the microhardness of various esthetic restorative materials. Materials and Methods : The curing depth and microhardness of a compomer (Dyract Extra, a resin-modified glass ionomer (Vitremer, a packable composite (Sculpt It, an ormocer (Admira, a hybrid composite (Tetric Ceram, two microhybrid composites (Miris and Clearfil Photo Posterior and, a nanofil composite (Filtek Supreme were determined using a scraping method and a hardness tester. A total of 320 samples were prepared using the eight different materials (n = 10 samples for each subgroup. The scraping test was based on ISO 4049:2000. Vicker′s microhardness testing was carried out using hardness tester (Zwick 3212. Data were analyzed using one-way analysis of variance (ANOVA, Bonferroni and the Kolmogorov-Smirnov tests. Results : Best microhardness results were obtained with the LED light curing units and Tetric EvoCeram and Filtek Supreme achieved the highest hardness values. The nanofil composite, Filtek Supreme, showed the best curing depth results in all the tested light curing systems. Conclusions : The LEDs were found to be more successful than the halogen units with respect to both curing depth and microhardness properties.

  10. 烤房类型对烤后烟叶质量的影响%Effect of Differont Types of Curing Barns on Tobacoo Leaf Quantity after Curing

    Institute of Scientific and Technical Information of China (English)



    [目的]考察3种类型烤房在烟叶鲜叶初加工过程中的整体效果.[方法]采用云南烟区普遍使用的气流下降式密集烤房密集型烤房、气流上升式密集烤房和普通立式炉小烤房3种烤房,分析比较不同类型烤房烤后烟叶的主要化学成分、物理特性、外观等级、评吸质量的差异.[结果]不同类型烤房烤后烟叶中上等烟叶比例气流下降式密集烤房比普通立式炉小烤房密集烤房分别高出2.86%和0.87%,比气流上升式密集烤房高出7.75%和4.29%;不同类型烤房烤后烟叶根据多数化学指标均为气流下降式密集烤房烤房烤后烟叶化学成分最为协调,气流上升式密集烤房次之,普通立式炉小烤房较差;不同类型烤房烤后上中下部位烟叶感官质量和物理特性均为气流下降式密集烤房最好,气流上升式密集烤房次之,普通立式炉小烤房效果较差.[结论]气流下降式密集电烤房结构设计合理可以推广应用.%[ Objective] To investigate the effect of three types of curing bams on the primary processing quality of fresh tobacco leaves. [ Method] Airflow-descending dense curing barna,airflow-ascending dense curing bams and common vertical furnace-curing bams in Yunnan tobacco area were adopted for analyzing and comparing the difference of main chemical components,physical characteristics,appearance grade and smoking quality of tobaccos cured by the three types of curing bamB. [ Result ] The medium and high-grade tobacco proportions after being cured by the airflow-descending dense curing barns were higher than that by the common vertical furnace min-curing bams and dense curing bams by 2.86% and 0.87% respectively,and higher than that by airflow-ascending dense curing bams hy 7.75% and 4.29%. According to a majority of chemical indicators,the tobacco chemical components cured by airflow-descending dense curing bams were the most coordinate,followed by the airflow

  11. Cure-WISE: HETDEX Data Reduction with Astro-WISE (United States)

    Snigula, J. M.; Drory, N.; Fabricius, M.; Landriau, M.; Montesano, F.; Hill, G. J.; Gebhardt, K.; Cornell, M. E.


    The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX, Hill et al. 2012b) is a blind spectroscopic survey to map the evolution of dark energy using Lyman-alpha emitting galaxies at redshifts 1.9currently receives a wide-field upgrade (Hill et al. 2012a) to accomodate the spectrographs and to provide the needed field of view. Over the projected five year run of the survey we expect to obtain approximately 170 GB of data each night. For the data reduction we developed the Cure pipeline, to automatically find and calibrate the observed spectra, subtract the sky background, and detect and classify different types of sources. Cure employs rigorous statistical methods and complete pixel-level error propagation throughout the reduction process to ensure Poisson-limited performance and meaningful significance values. To automate the reduction of the whole dataset we implemented the Cure pipeline in the Astro-WISE framework. This integration provides for HETDEX a database backend with complete dependency tracking of the various reduction steps, automated checks, and a searchable interface to the detected sources and user management. It can be used to create various web interfaces for data access and quality control. Astro-WISE allows us to reduce the data from all the IFUs in parallel on a compute cluster. This cluster allows us to reduce the observed data in quasi real time and still have excess capacity for rerunning parts of the reduction. Finally, the Astro-WISE interface will be used to provide access to reduced data products to the general community.

  12. [Stress profile during curing contraction of composite resin adhesives]. (United States)

    Kunzelmann, K H; Hickel, R


    The wall-to-wall curing contraction of thin composite resin layers was recorded with a tensometer. The composite resin was applied to cylindrically shaped ceramic sample holders with diameters of 3 mm, 4 mm and 8 mm. The distances of the sample holders was set at 50 microns, 100 microns, 150 microns, 200 microns and 300 microns. The shrinkage stress recordings clearly show that the shrinkage forces are governed by the distance of the sample holders and not by the volume or the configuration factor of the composite resin layers.

  13. Invasive Scedosporium sternal osteomyelitis following lung transplant: Cured

    Directory of Open Access Journals (Sweden)

    E.J. Denton


    Full Text Available Scedosporium is an important pathogen in cystic fibrosis (CF and post-transplant but rarely causes invasive infection. Treatment remains challenging, particularly due to inherent resistance to multiple antifungal agents. We present a young man with CF who developed invasive sternal and rib infection 10-months following lung transplant. The infection has been clinically and radiologically cured with extensive surgery and triazole therapy. This case highlights the importance of adjunctive surgery in addition to prolonged triazole treatment to manage invasive Scedosporium infections in immunosuppressed patients.

  14. Chosen quality parameters of pork sausage produced without curing mixture

    Directory of Open Access Journals (Sweden)

    Adam Kostecki


    Full Text Available Background. The aim of this study was to determine the infl uence of the dried celeriac juice addition, as a nitrogenous compounds sources, on the quality of the experimental pork sausage. Material and methods. In the sausages with vegetable preparation addition and in traditionally cured sausages amount of the sodium nitrate (III and sodium nitrate (V was determined (in the batter and 24 h after production. Moreover the total number of aerobic bacteria, number of coli forms, anaerobic survived bacteria, coagulase positive staphylococci, Listeria monocytogenes and occurrence of Salmonella in 25 g (according to Polish Standards was determined during sausages storing (after 2, 14 and 21 days. Also sensory evaluation was carried out (after 2 and 14 days. After 2, 7, 14 and 21 days the amount of drip loss in the package was determined. Result. In the experimental sausage produced with the addition of vegetable preparation (E0, the content was 2.2 times higher of sodium nitrate (V while sodium nitrate (III three times lower, compared to traditionally cured sausages (K. In the E0 sausages faster aerobic microorganisms proliferation was observed. However, in these products, in comparison to the control group (K, no higher contamination with coliform bacteria, anaerobic sporulating bacteria, coagulase positive Staphylococci, Listeria monocytogenes or Salmonella was found. The sensory evaluation (colour in cross-section, fl avour, taste, consistency showed no statistically significant difference between the experimental sausages. Conclusions. In the sausages produced with dried celeriac juice addition there was above twice more sodium nitrate (V and threefold less sodium nitrate (III in comparison to traditionally cured sausages and faster growth of aerobic bacteria was demonstrated. Sensory quality of ‘cold’ and ‘hot’ sausages without curing salt was worse, but the score number was never lower than 4,1, so the sausages were accepted. In the

  15. Solid Rocket Fuel Constitutive Theory and Polymer Cure (United States)

    Ream, Robert


    Solid Rocket Fuel is a complex composite material for which no general constitutive theory, based on first principles, has been developed. One of the principles such a relation would depend on is the morphology of the binder. A theory of polymer curing is required to determine this morphology. During work on such a theory an algorithm was developed for counting the number of ways a polymer chain could assemble. The methods used to develop and check this algorithm led to an analytic solution to the problem. This solution is used in a probability distribution function which characterizes the morphology of the polymer.

  16. Preliminary toxicological study of Sylgard 184 encapsulating resin: curing agent

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.M.; Drake, G.A.; London, J.E.; Thomas, R.G.


    The acute oral LD/sub 50//sup 30/ values for Sylgard 184 (100 parts encapsulating resin plus 10 parts curing agent) were greater than 5 g/kg in rats and mice. According to classical guidelines, the mixture would be considered slightly toxic or practically nontoxic in both species. Skin application studies in the rabbit demonstrated the mixture to be mildly irritating. Eye irritation tests, also in the rabbit, showed the Sylgard 184 mixture to be a mild but transitory irritant. The sensitization study in the guinea pig demonstrated the mixture to be a very mild sensitizer in two of six animals.

  17. Chemical Interpretation of the Relaxed Permittivity during Epoxy Resin Cure. (United States)


    contributions of other polar groups and their time variation are included. The isothermal cure of a stoichiometric mixture of a DGEBA epoxy resin, EPON 825. with...the DGEBA molecule, and since it contains only a single epoxide. this material does not crosslink. At low temperatures and at all frequencies, the...ratios of DGEBA and DDS gave an epoxy dipole moment of 8.SE-30 C-u and an amine dipole moment of 19.8E-30 C-m [10]. The experimental data and the curves

  18. Curing characteristics of chlorosulphonated polyethylene and natural rubber blends


    M. MARINOVIC-CINCOVIC; J. BUDINSKI SIMENDIC; Markovic, G.; Radovanovic, B.


    The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV) and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40) blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microsc...

  19. Low toxicity aromatic diamine curing agents for adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Dorsey, G.F.


    Increasing severity of regulations for handling of hazardous materials has led to formulation of adhesives with considerably lowered toxicities for use at the Oak Ridge Y-12 Plant. Fundamental was the development of Asilamine aromatic diamines, a family of liquid aromatic diamines useful as substitutes for methylenedianiline (MDA), a widely used adhesives curing agent. The use of Asilamine has allowed us to continue operations without dealing with expensive measures for regulation of MDA as a carcinogen promulgated by the Occupational Safety and Health Administration (OSHA).

  20. The Mechanism of Carotenoid Degradation in Flue-Cured Tobacco and Changes in the Related Enzyme Activities at the Leaf-Drying Stage During the Bulk Curing Process

    Institute of Scientific and Technical Information of China (English)

    SONG Zhao-peng; LI Tong-shuai; ZHANG Yong-gang; CAO Hui-jing; GONG Chang-rong; ZHANG Wei-jian


    The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology.The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University,China,based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity.The results showed that the carotenoid degradation components(β-carotene,lutein,neoxanthin,and violaxthin)decreased gradually at the color-fixing stage during the bulk curing process.The carotenoid degradation components viz.,β-carotene,lutein,neoxanthin,and violaxthin at the slow heating curing(T1)were relatively higher than the rapid heating curing(T2)accounting for 10,2,32 and 32%respectively,but there were no differences among treatments(P>0.05).The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant.The lipoxygenase,phenylalanine ammonialyase,peroxidase,and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage.The slow heating could regulate the change in various enzymes' activities reasonably,making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately.Meanwhile,it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.

  1. Influence of curing rate of resin composite on the bond strength to dentin

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Asmussen, E; Peutzfeldt, A


    @ 1000 mW/cm2) for all groups. A split Teflon mold was clamped to the treated dentin surface and filled with resin composite. The rate of cure was varied, using one of four LED-curing units of different power densities. The rate of cure was also varied using the continuous or pulse-delay mode....... In continuous curing mode, in order to give an energy density totaling 16 J/cm2, the power densities (1000, 720, 550, 200 mW/cm2) emitted by the various curing units were compensated for by the light curing period (16, 22, 29 or 80 seconds). In the pulse-delay curing mode, two seconds of light curing at one...... of the four power densities was followed by a one-minute interval, after which light cure was completed (14, 29, 27 or 78 seconds), likewise, giving a total energy density of 16 J/cm2. The specimens produced for each of the eight curing protocols and two resin composites (Tetric EvoCeram, Ivoclar Vivadent...

  2. Benefits of Sealed-Curing on Compressive Strength of Fly Ash-Based Geopolymers

    Directory of Open Access Journals (Sweden)

    Sujeong Lee


    Full Text Available There is no standardized procedure for producing geopolymers; therefore, many researchers develop their own procedures for mixing and curing to achieve good workability and strength development. The curing scheme adopted is important in achieving maximum performance of resultant geopolymers. In this study, we evaluated the impact of sealed and unsealed curing on mechanical strength of geopolymers. Fly ash-based geopolymers cured in sealed and unsealed moulds clearly revealed that retention of water during curing resulted in superior strength development. The average compressive strength of sealed-cured geopolymers measured after 1 day of curing was a modest 50 MPa, while after 7 day curing the average compressive strength increased to 120~135 MPa. In the unsealed specimens the average compressive strength of geopolymers was lower; ranging from 60 to 90 MPa with a slight increase as the curing period increased. Microcracking caused by dehydration is postulated to cause the strength decrease in the unsealed cured samples. These results show that water is a crucial component for the evolution of high strength three-dimensional cross-linked networks in geopolymers.

  3. Synergistic effect of graphene-oxide-doping and microwave-curing on mechanical strength of cement (United States)

    Qin, Hao; Wei, Wei; Hang Hu, Yun


    In this communication, efficient reinforcement of cement matrix was obtained by graphene-oxide (GO) doping and curing treatments. The compressive strength of plain cement is 14.3±0.2 MPa. When the cement contained 0.5 wt% GO, its strength reached 19.4±0.9 MPa. The strength can be further enhanced by curing, which follows the sequence: Microwave-cured GO-cement > Microwave and water-cured GO-cement > Water-cured GO-cement > GO-cement without curing. The highest compressive strength (32.4±0.7 MPa), which was achieved by combining GO-doping and microwave curing, is 126.6±8.1% higher than that without GO-doping and microwave curing. This demonstrates a synergistic effect of GO doping and microwave-curing on the strength of cement composite materials. Furthermore, X-ray diffraction (XRD), Fourier transform Infrared Spectroscopy (FTIR), and field emission scanning electron microscope (FESEM) characterizations revealed that the combination of GO doping and microwave-curing remarkably accelerated cement hydration, leading to the regular and compact structure and thus a high compressive strength. This work provides a new way to improve the mechanical properties of cement composites.

  4. Comparative efficiency of plasma and halogen light sources on composite micro-hardness in different curing conditions


    Dietschi, Didier; Marret, N; Krejci, Ivo


    Recent developments have led to the introduction of high power curing lights, which are claimed to greatly reduce the total curing time. This study evaluated the effectiveness of a plasma-curing device (Apollo 95 E) and a halogen device (Heliolux DLX), in different curing conditions.

  5. Testing the Chemical/Structural Stability of Proton Conducting Perovskite Ceramic Membranes by in Situ/ex Situ Autoclave Raman Microscopy. (United States)

    Slodczyk, Aneta; Zaafrani, Oumaya; Sharp, Matthew D; Kilner, John A; Dabrowski, Bogdan; Lacroix, Olivier; Colomban, Philippe


    Ceramics, which exhibit high proton conductivity at moderate temperatures, are studied as electrolyte membranes or electrode components of fuel cells, electrolysers or CO2 converters. In severe operating conditions (high gas pressure/high temperature), the chemical activity towards potentially reactive atmospheres (water, CO2, etc.) is enhanced. This can lead to mechanical, chemical, and structural instability of the membranes and premature efficiency loss. Since the lifetime duration of a device determines its economical interest, stability/aging tests are essential. Consequently, we have developed autoclaves equipped with a sapphire window, allowing in situ Raman study in the 25-620 °C temperature region under 1-50 bar of water vapor/gas pressure, both with and without the application of an electric field. Taking examples of four widely investigated perovskites (BaZr0.9Yb0.1O3-δ, SrZr0.9Yb0.1O3-δ, BaZr0.25In0.75O3-δ, BaCe0.5Zr0.3Y0.16Zn0.04O3-δ), we demonstrate the high potential of our unique set-up to discriminate between good/stable and instable electrolytes as well as the ability to detect and monitor in situ: (i) the sample surface reaction with surrounding atmospheres and the formation of crystalline or amorphous secondary phases (carbonates, hydroxides, hydrates, etc.); and (ii) the structural modifications as a function of operating conditions. The results of these studies allow us to compare quantitatively the chemical stability versus water (corrosion rate from ~150 µm/day to less than 0.25 µm/day under 200-500 °C/15-80 bar PH2O) and to go further in comprehension of the aging mechanism of the membrane.

  6. Autoclave treatment of pig manure does not reduce the risk of transmission and transfer of tetracycline resistance genes in soil: successive determinations with soil column experiments. (United States)

    Kang, Yijun; Gu, Xian; Hao, Yangyang; Hu, Jian


    The increasing use of antibiotics, especially tetracycline, in livestock feed adversely affects animal health and ecological integrity. Therefore, approaches to decrease this risk are urgently needed. High temperatures facilitate antibiotic degradation; whether this reduces transmission risk and transfer of tetracycline-resistant bacteria (TRBs) and tetracycline resistance genes (TRGs) in soil remains unknown. Successive experiments with soil columns evaluated the effects of autoclaving pig manure (APM) on soil TRB populations and TRGs over time at different soil depths. The data showed sharp increases in TRB populations and TRGs in each subsoil layer of PM (non-APM) and APM treatments within 30 days, indicating that TRBs and TRGs transferred rapidly. The level of TRBs in the upper soil layers was approximately 15-fold higher than in subsoils. TRBs were not dependent on PM and APM levels, especially in the late phase. Nevertheless, higher levels of APM led to rapid expansion of TRBs as compared to PM. Moreover, temporal changes in TRB frequencies in total culturable bacteria (TCBs) were similar to TRBs, indicating that the impact of PM or APM on TRBs was more obvious than for TCBs. TRBs were hypothesized to depend on the numbers of TRGs and indigenous recipient bacteria. In the plough layer, five TRGs (tetB, tetG, tetM, tetW, and tetB/P) existed in each treatment within 150 days. Selective pressure of TC may not be a necessary condition for the transfer and persistence of TRGs in soil. High temperatures might reduce TRBs in PM, which had minimal impact on the transmission and transfer of TRGs in soil. Identifying alternatives to decrease TRG transmission remains a major challenge.

  7. Bond strength between composite resin and resin modified glass ionomer using different adhesive systems and curing techniques


    Alireza Boruziniat; Samineh Gharaei


    Aim: To evaluate bond strength between RMGI and composite using different adhesive systems and curing techniques. Materials and Methods: Sixty prepared samples of RMGI were randomly divided into six groups according to adhesive systems (total-etch, two-step self-etch and all-in-one) and curing techniques (co-curing and pre-curing). In co-curing technique, the adhesive systems were applied on uncured RMGI samples and co-cured together. In the pre-curing technique, before application of adh...

  8. Effect of Different Thicknesses of Pressable Ceramic Veneers on Polymerization of Light-cured and Dual-cured Resin Cements (United States)

    Cho, Seok-Hwan; Lopez, Arnaldo; Berzins, David W.; Prasad, Soni; Ahn, Kwang Woo


    Aim This study evaluated the effects of ceramic veneer thicknesses on the polymerization of two different resin cements. Materials and Methods A total of 80 ceramic veneer discs were fabricated by using a pressable ceramic material (e.max Press; Ivoclar Vivadent) from a Low Translucency (LT) ingot (A1 shade). These discs were divided into light-cured (LC; NX3 Nexus LC; Kerr) and dual-cured (DC; NX3 Nexus DC; Kerr) and each group was further divided into 4 subgroups, based on ceramic disc thickness (0.3 mm, 0.6 mm, 0.9 mm, and 1.2 mm). The values of Vickers microhardness (MH) and degree of conversion (DOC) were obtained for each specimen after a 24-hour storage period. Association between ceramic thickness, resin cement type, and light intensity readings (mW/cm2) with respect to microhardness and degree of conversion was statistically evaluated by using ANOVA. Results For the DOC values, there was no significant difference observed among the LC resin cement subgroups, except in the 1.2 mm subgroup; only the DOC value (14.0 ± 7.4%) of 1.2 mm DC resin cement had significantly difference from that value (28.9 ± 7.5%) of 1.2 mm LC resin cement (P.05). Conclusion The degree of conversion and hardness of the resin cement was unaffected with veneering thicknesses between 0.3 and 0.9 mm. However, the DC resin cement group resulted in a significantly lower DOC and MH values for the 1.2 mm subgroup. Clinical Significance While clinically adequate polymerization of LC resin cement can be achieved with a maximum 1.2 mm of porcelain veneer restoration, the increase of curing time or light intensity is clinically needed for DC resin cements at the thickness of more than 0.9 mm. PMID:26162252

  9. Preparation, curing kinetic and properties of a novel amine with flexible polyoxypropylene side chain curing agent for epoxy resin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guiyou, E-mail:; Jiang, Guanlan; Zhang, Jie


    Highlights: • Novel amines with different length of flexible polyoxypropylene side chain (AFPE) were synthesized. • The non-isothermal curing kinetics of DGEBA/AFPEs were studied in detail. • Structure, morphology and physical properties of AFPEs modified diethylenetriamine/DGEBA systems were studied, and results showed that AFPE was a novel and effective toughening agent for epoxy resins. - Abstract: A novel amine with flexible polyoxypropylene side chain (AFPE) was synthesized and characterized with FT-IR and NMR. Then, AFPEs with different molecular weight were used as a curing agent for diglycidyl ether of bisphenol A (DGEBA), and non-isothermal reaction was detected with DSC. The kinetic parameters of the curing process were determined by Málek method. A two-parameter (m, n) autocatalytic model (Šesták–Berggren equation) was found to be adequate to describe the reaction-controlled kinetics of the studied epoxy resins, yet was insufficient in depicting the diffusion-controlled kinetics of the epoxy resins. The values of E{sub a} depended on the molecular weight of AFPEs, and increased with longer polyoxypropylene chain length in the AFPE. Dynamic mechanical analysis of AFPEs modified DGEBA/diethylenetriamine systems found that with the increasing molecular weight of AFPEs, α relaxation temperature, β relaxation temperature and crosslinking density decreased, while impact strength and elongation at break improved. From scanning electron microscope, tensile surfaces were rougher and sizes of cavities in the surface became larger with the increasing molecular weight of AFPEs. Our study showed that AFPE was a novel and effective toughening agent for epoxy resins.

  10. The Mexican asthma cure. Systemic steroids for gullible gringos. (United States)

    Rubin, B K; LeGatt, D F; Audette, R J


    Asthmatic patients from western Canada and the United States have reported that after visits to an asthma clinic in Mexicali, Mexico, they return home substantially improved or cured having received "a bronchodilator medication unavailable in the United States or Canada because of the big drug companies." Analysis of these medications reveals that the most commonly prescribed combination is the glucocorticoid triamcinolone (unscored white tablets) and the antihistamine chlorpheniramine (coated biconvex orange or red tablets). Occasionally benzodiazepines are added to these medications. The patients are assured that the medications which they have been given are free of side effects and specifically, that corticosteroids are not used. Such therapy is dangerous to the patient who not only is unaware of the medications that he or she is taking, but is unlikely to mention this therapy to his or her physician. These patients risk drug interactions, medication side effects, and the possibility of adrenal failure either with a stress to their system or on withdrawal of drug treatment. Patients are also at risk of abandoning safer forms of asthma therapy for the miracle cure. We, too, are partially responsible for these unethical practices by avoiding the use of steroids and undertreating our patients at times, leaving them unnecessarily restricted and eager for any form of relief.

  11. Definition of Cure in Childhood Acute Myeloid Leukemia (United States)

    Rubnitz, Jeffrey E.; Inaba, Hiroto; Leung, Wing; Pounds, Stanley; Cao, Xueyuan; Campana, Dario; Ribeiro, Raul C.; Pui, Ching-Hon


    Background A better understanding of when cure can be declared in childhood acute myeloid leukemia (AML) would reduce anxiety and improve quality of life of AML survivors. We determined the likelihood of patients with AML to maintain long-term remission after completion of therapy. Patients and Methods The cumulative risk of relapse, time to relapse, event-free survival and overall survival were analyzed for 604 patients with AML enrolled in seven successive clinical trials, divided into 3 treatment eras (1976–1991, 1991–1997, 2002–2008). Results The median time to relapse did not change over time (0.93 years vs. 0.76 vs. 0.8 years for each consecutive era, P = .22) but the risk of relapse decreased significantly (5-year cumulative incidence of relapse 52.6% ± 3.1% vs. 31.5% ± 3.9% vs. 22.0% ± 3.0%, P < .001). Among patients who were in remission 4 years from diagnosis, the probabilities of relapse were 1.7%, 2.9%, and 0.9%, respectively. In the most recent era, all 44 relapses except one occurred within four years of diagnosis. Conclusion Children with AML who are treated with contemporary therapy and remain in remission four years from diagnosis are likely cured. Although late relapses and late deaths from other causes are rare, long-term follow up of survivors is necessary for timely management of late adverse effects. PMID:24798038

  12. Blue light curing units--a dermatological hazard? (United States)

    Chadwick, R G; Traynor, N; Moseley, H; Gibbs, N


    The setting reactions of a large number of dental materials are activated upon exposure to visible blue light emitted from a curing unit. Although the wavelength (lambda) from such devices is principally in the visible spectrum (lambda > 400 nm) a small amount of ultraviolet radiation (UV) is also present. Little attention has been paid to the consequences of such exposure upon the skin of dental surgeons' fingers. This investigation studied the level of UVA I (lambda = 340-400 nm) emitted by three commonly used polymerisation sources and assessed the level of protection afforded by six brands of surgical glove. The integrated irradiances of the Translux, Topaz T100 and Heliomat units in the UVA I range were 15861, 3611 and 305 mW/m2 respectively. For all gloves the mean % transmission, at lambda = 400 nm, was less than 4% with the exception of one brand where, in the stretched state, the level of transmission was 7%. It is concluded that the risk of initiating adverse dermatological consequences as a result of exposure to UVA I, emitted by light polymerisation units, is minimal in normal usage. The combined effects of exposure to radiation of this type and contamination of the fingers with quantities of irritant chemicals, such as found in many dental materials, are unknown. Due to the ability of the gloves to shield the skin from both chemicals and UVA I it is recommended that gloves are routinely worn for all light curing procedures.

  13. Modern Medicine: Towards Prevention, Cure, Well-being and Longevity

    Directory of Open Access Journals (Sweden)

    Singh Ajai


    Full Text Available Modern medicine has done much in the fields of infectious diseases and emergencies to aid cure. In most other fields, it is mostly control that it aims for, which is another name for palliation. Pharmacology, psychopharmacology included, is mostly directed towards such control and palliation too. The thrust, both of clinicians and research, must now turn decisively towards prevention and cure. Also, longevity with well-being is modern medicine′s other big challenge. Advances in vaccines for hypertension, diabetes, cancers etc, deserve attention; as also, the role of meditation, yoga, spirituality etc in preventing disease at various levels. Studies on longevity, life style changes and healthy centenarians deserve special scrutiny to find what aids longevity with wellbeing. A close look at complementary and alternative medicine is needed to find any suitable models they may have, cutting aside their big talk and/or hostility towards mainstream medical care. Medicine is a manifestation of the human eros, and should not become a means of its thanatos. It must realise its true potential, so that eros prevails, and thanatos prevails only ultimately, not prematurely.

  14. Curing characteristics of chlorosulphonated polyethylene and natural rubber blends

    Directory of Open Access Journals (Sweden)



    Full Text Available The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40 blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microscopy (SEM. The results showed that the scorch time decreased with increasing SMR 20 CV and Pergut S 40 contents. This observation is attributed to the increasing solubility of sulfur, as the content of SMR 20 CV and Pergut S 40 in the composition increased. For temperatures greater than 140 oC, the dependence of the scorch time on blend ratios diminishes, as enough thermal energy is available to overcome the activation energy of vulcanization. The differing curing characteristics of the two blends is explained by the compatibility factor of the respective blend. Morphological analysis of the blends shows a very satisfactory agreement.

  15. Effects of Amine and Anhydride Curing Agents on the VARTM Matrix Processing Properties (United States)

    Grimsley, Brian W.; Hubert, Pascal; Song, Xiaolan; Cano, Roberto J.; Loos, Alfred C.; Pipes, R. Byron


    To ensure successful application of composite structure for aerospace vehicles, it is necessary to develop material systems that meet a variety of requirements. The industry has recently developed a number of low-viscosity epoxy resins to meet the processing requirements associated with vacuum assisted resin transfer molding (VARTM) of aerospace components. The curing kinetics and viscosity of two of these resins, an amine-cured epoxy system, Applied Poleramic, Inc. VR-56-4 1, and an anhydride-cured epoxy system, A.T.A.R.D. Laboratories SI-ZG-5A, have been characterized for application in the VARTM process. Simulations were carried out using the process model, COMPRO, to examine heat transfer, curing kinetics and viscosity for different panel thicknesses and cure cycles. Results of these simulations indicate that the two resins have significantly different curing behaviors and flow characteristics.

  16. UV curing of a liquid based bismaleimide-containing polymer system

    Directory of Open Access Journals (Sweden)


    Full Text Available A new liquid formulation of commercial bismaleimide and n-acryloylmorpholine was prepared that could be UV cured as an alternative to traditional thermal cure methods presently used for BMI in the industry. UV curing was shown to be an efficient method which promoted the reaction rate significantly and was able to achieve this at low temperatures (30–50°C. A free radical polymerization approach has been used to explain the cure mechanism and cure kinetics, using data elucidated from the DPC and FTIR. The cured thin film was shown to achieve very high thermal stability (~400°C, with the BMI shown to retard the thermal degradation temperature and rate.

  17. Activities of RILEM Technical Committee: Internal Curing of Concrete and Anticipated Research

    DEFF Research Database (Denmark)

    Kovler, Konstantin; Jensen, Ole Mejlhede

    of Concrete” of the International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM). The authors of this short communication served as a chair (K. Kovler) and secretary (O.M. Jensen) of the TC. The regular and corresponding members were acknowledged RILEM experts......Novel methods of shrinkage mitigation, based on special advanced methods of internal curing (IC), are currently being intensively studied in research groups in several countries. They have been the focus of the State-of-the-Art report prepared by the Technical Committee TC 196-ICC “Internal Curing...... in ACI, JCI (Japan Concrete Institute) and other well-known research associations in the field of concrete science and engineering. Internal curing, as well as external curing, can be classified into two categories: • Internal water curing (sometimes called “water entrainment”), when the curing agent...

  18. Dynamic cure measurement of dental polymer composites using optical coherence tomography (United States)

    Tomlins, Peter H.; Palin, Will M.; Shortall, Adrian C.


    Dental amalgam is being increasingly replaced by Light-activated resin-based dental composites. However, these materials are limited by inefficient setting reactions as a function of depth, constraining the maximum extent of cure and reducing biocompatibility. In this paper we demonstrate a novel metrological tool for dynamic monitoring of refractive index and thickness change through curing resins using spectral-domain optical coherence tomography. We present real-time measurements from pre- to post-cure of a series of un-filled bisphenol-A diglycidyl ether dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) resins with different inhibitor concentrations. Our results demonstrate that refractive index measurements are sensitive to the extent of cure of such resins and that the inhibitor concentration strongly affects the cure dynamics and final extent of cure.

  19. Effect of Curing Procedure on the Properties of Copper-Powder-Filled Conductive Adhesives

    Institute of Scientific and Technical Information of China (English)

    ZHENG Xiaoling; ZHANG Lulu; YOU Min; WU Jianhao; YU Haizhou; YANG Derong; MAO Yuping


    By means of testing the shear strength with single lap joint, measuring electrical resistivity for cured products and the curing strain with strain gauges, the effect of cure parameters on the properties of HT1012 conductive adhesive filled with copper powder was investigated, and the residual stress in the conductive adhesives was also estimated. The experimental results show that the properties such as shear strength of the adhesives, electrical resistivity of products as well as the residual stress of cured HT1012 copper-filled conductive adhesive were evidently affected by curing temperature and time. The diagrams of scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) were also used to determine the properties. The higher mechanical property was achieved under the condition of curing the adhesive 3h at 60℃ as the density of the hydrogen links or linkages existed in the adhesive was relatively higher and the lower electrical resistivity occurred at 80℃.

  20. Influence of Curing Condition on the Adhesive Strength of EVA Modified Mortar to Tile

    Institute of Scientific and Technical Information of China (English)


    The reducing water effectiveness of EVA latex and powder was observed. Adhesive strength of EVA modified mortar to tile under different curing condition was studied. And the adhesive strengths of mortars modified by EVA latex and by EVA powder were compared. The results show that the reducing water effectiveness is improved by 36.12% and 21.55%, respectively, when the content of EVA latex and powder are 8% and 4%. EVA latex and powder can improve the adhesive strength of modified mortar to tile under the standard curing, high temperature curing, and freeze-thaw circle curing.EVA latex can improve the water resistance obviously, besides improve the adhesive strengths of standard curing and high temperature curing, comparing with EVA powder.