WorldWideScience

Sample records for elastomeric gasket materials

  1. Replacement of thermal column elastomeric gasket in pool type research reactors based on ageing and radiation degradation

    International Nuclear Information System (INIS)

    Pool type research reactors are designed with Thermal column facilities to irradiate samples at different flux levels of thermal neutrons. The sealing of demineralised pool water between stainless steel lined pool wall and the Aluminium Thermal column plate is achieved by an elastomeric gasket. The gasket joint is subjected to pool water temperature ranging from 25degC to 45degC and radiation field of the order of 104 -106 R/hr. The gasket loses its sealing properties due to ageing and radiation degradation after a few years, leading to the leakage and loss of the pool water. Though degradation of the gasket is, generally, predictable, some amount of uncertainty always remains in the leakage rate. The paper describes the study of a few elastomers in radiation environment and replacement of the Thermal column gasket of a swimming pool type research reactor. It includes the details of features like planning and scheduling, the actual sequential execution of the job, various problems encountered and corrective measures applied, engineering and radiological safety measures adopted, development of remote tools, disassembly and reassembly procedure and finally satisfactory completion of the site job in high radiation environment with minimum time and man rem consumption. (author)

  2. Diffusion welding of magnetic materials through porous gaskets made of rolled strips

    International Nuclear Information System (INIS)

    Results are presented of studying peculiarities of producing rolled porous gaskets from nickel strips and formation of magnetic material joints by diffusion welding through such gaskets. The optimum mode of pyrolysis (573 K, 9 K/min) ensuring reduction of formate nickel with specific surface 16-18 m2/g is established. 60-80 ?m thick strips with 50-60% porosity prepared at the 190 mm/min rolling rate are recommended as porous nickel gaskets. Optimum working parameters are determined for diffusion welding of magnetic-soft materials with magnetic-hard ones through porous nickel gaskets ensuring the formation of precise joints with preservation of initial physico-mechanical properties without development of volumetric plastic strains

  3. Evaluation of elastomers as gasket materials in pneumatic and hydraulic systems

    Science.gov (United States)

    Bright, C. W.; Lockhart, B. J.

    1972-01-01

    In the search for superior materials from which to make gaskets for pneumatic and hydraulic systems, promising materials were selected and tested. The testing was conducted in two phases. Those materials that passed the tests of Phase 1 were tested in Phase 2, and categorized in the order of preference.

  4. A guide to the suitability of elastomeric seal materials for use in radioactive material transport packages

    International Nuclear Information System (INIS)

    Elastomeric seals are a frequently favoured method of sealing Radioactive Material Transport (RMT) packages. The sealing technology has been proven for many years in a wide range of industrial applications. The requirements of the RMT package applications, however, are significantly different from those commonly found in other industries. This guide outlines the Regulatory performance requirements placed on an RMT package sealing system by TS-R-1, and then summarises the material, environment and geometry characteristics of elastomeric seals relevant to RMT applications. Tables in the guide list typical material properties for a range of elastomeric materials commonly used in RMT packages

  5. Advanced elastomeric seal design and material for automotive crankshaft applications

    Energy Technology Data Exchange (ETDEWEB)

    Jackowski, R.; Keller, R.; Strubel, D.

    1987-01-01

    The small, lightweight engines of today require elastomeric lip seals to operate at higher shaft speeds and elevated temperatures while retained in aluminum housings and subjected to aggressive cil additives. The use of fluorelastomer in place of silicone material has provided improved seal performance in engine applications. An advanced crankshaft seal, incorporating a half rubber/half metal O.D. and a superior fluoroelastomer material, has been developed to improve seal installation and retention in aluminum housings and extend seal life beyond the present seal technology.

  6. Evaluation of effective material properties of spiral wound gasket through homogenization

    International Nuclear Information System (INIS)

    In this paper, a homogenization methodology is proposed to determine the material properties of spiral wound gaskets (SWGs) using finite element analysis through representative volume elements (RVE) of the gaskets. The constituents of this RVE are described by elasto-plastic material properties. The RVE are subjected to six load cases and the volume averaged responses are analyzed simultaneously to predict the anisotropic properties. The mechanical behaviour is simplified to an orthotropic material model with Hill's plasticity model and the properties are verified with micro-mechanical simulation and experimental results available in the literature. Reasonable agreement is obtained between the results. Formulae for elastic properties are also derived by a simplified analytical method based on lamination theory and compared with those obtained from homogenization.

  7. Performance testing of elastomeric seal materials under low and high temperature conditions: Final report

    Energy Technology Data Exchange (ETDEWEB)

    BRONOWSKI,DAVID R.

    2000-06-01

    The US Department of Energy Offices of Defense Programs and Civilian Radioactive Waste Management jointly sponsored a program to evaluate elastomeric O-ring seal materials for radioactive material shipping containers. The report presents the results of low- and high-temperature tests conducted on 27 common elastomeric compounds.

  8. Performance testing of elastomeric seal materials under low and high temperature conditions: Final report

    International Nuclear Information System (INIS)

    The US Department of Energy Offices of Defense Programs and Civilian Radioactive Waste Management jointly sponsored a program to evaluate elastomeric O-ring seal materials for radioactive material shipping containers. The report presents the results of low- and high-temperature tests conducted on 27 common elastomeric compounds

  9. New Soft Polymeric Materials Applicable as Elastomeric Transducers

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Skov, Anne Ladegaard

    An elastomer is a material characterized by the capability to regain its original size and shape after being deformed (stretched or distorted). An ideal elastomer for electroactive polymer (EAP) applications is a system characterized by high extensibility, flexibility and a good mechanical fatigue. Dielectric elastomers (DEs) are part of electronic EAPs presenting a good combination of electromechanical properties such as high achievable strains and stresses, fast response speeds, long lifetime, high reliability and high efficiency1. Subjected to a voltage, a polymeric electroactive material sandwiched between two compliant electrodes will reduce its thickness and expand its area. The electrical energy transformed into mechanical energy is called actuation and it is studied in the technology of elastomeric transducers. While DEs deform under high voltage, the actuation varies for different materials (ceramics2, glassy polymers3 or soft polymeric networks4-6). The strain actuation for stiff materials such asglassy or semicrystalline polymers is limited by the electrical breakdown7, while the deformation upon actuation for soft materials is limited by the electromechanical breakdown8. This paper presents new soft polymeric materials based on silicone with improved mechanical properties. Silicone elastomers exhibit good characteristics including biocompatibility, oxidation resistance, thermal stability, fast mechanical response with good reproducibility and stable mechanical behaviour over a wide range of temperature10-13. However, silicone elastomer has weak intermolecular forces among polymeric chains, which limits its mechanical strength. Mechanical properties may be improved using different methods (adding fillers14, interpenetrating network synthesis15 or bimodal network synthesis16). In the present study hyperswollen silicone networks are synthesized and rheologically characterized. Their viscoelastic properties make them good candidates for elastomeric transducers. Silicone networks are synthesized using ahydrosilylation reaction at room temperature between vinyl-terminated polydimethyl siloxanes (PDMS), a 4-functional crosslinker and a platinum catalyst. A ‘one-step two-pot’ mixing procedure is applied and to each premix 70% solvent (heptane) is added. The use of solvent causes networks with fewer entanglements, thus giving the polymeric chains opportunity to act as undisturbed ideal springs. The viscoelastic behavior as function of the applied frequency (LVE diagram) is shown for different hyperswollen networks with varying stoichiometric imbalance (r). The results are compared with results of similar un-swollen networks. The hyperswollen networks are significantly softer and still easy to handle. From a mechanical point of view, the materials for EAPs use have to be soft with sufficient mechanical strength so the rupture of the material can be avoided at high strain actuation. Considering the EAP requirements and the experimental data for the hyperswollen networks based on silicone, these materials may be considered as good alternatives for the EAP application.

  10. Irradiation cure processing of elastomeric components

    International Nuclear Information System (INIS)

    A process is described for the manufacture of an article containing elastomeric components comprising the steps of, 1) compounding a layer of elastomeric material; 2) partially curing the layer of elastomeric material by exposing it to irradiation by high-speed electrons sufficient to impart an improved green strength; 3) placing the partially cured layer of elastomeric material in contact with other elastomeric components; 4) shaping the layer of elastomeric material and other elastomeric components to substantially the conformation of the desired article, and 5) curing the layer of elastomeric material and the other elastomeric components. (author)

  11. Radiation resistance of ultra high molecular weight polyethylene and polyetheretherketone as materials for gasket and sealing

    International Nuclear Information System (INIS)

    Radiation resistance of ultra high molecular weight polyethylene (NL-W) and polyetheretherketone (PEEK-450G) was tested to select the gasket and sealing materials used in the piping and valve for high level radioactive liquid in reprocessing of nuclear fuel. The tensile, bending, hardness, and seal tests were carried out after 60Co-?-ray irradiation in air, in oxygen under pressure, and in nitric acid of 3N and 10N at room temperature. For NL-W, the degradation was small until 3.2 MGy by the irradiation in air and in nitric acid, then the sealing was maintained. However, the degradation was observed by the irradiation in oxygen under pressure, then, the physical properties and sealing would be loosed gradually with dose in air at very low dose rate irradiation. For PEEK-450G, the radiation degradation was very small in the these irradiation conditions, but it was observed to degrade in the case of high temperature in high concentration of nitric acid. (author)

  12. Developments in new aircraft tire tread materials. [fatigue life of elastomeric materials

    Science.gov (United States)

    Yager, T. J.; Mccarty, J. L.; Riccitiello, S. R.; Golub, M. A.

    1976-01-01

    Comparative laboratory and field tests were conducted on experimental and state-of-the-art aircraft tire tread materials in a program aimed at seeking new elastomeric materials which would provide improved aircraft tire tread wear, traction, and blowout resistance in the interests of operational safety and economy. The experimental stock was formulated of natural rubber and amorphous vinyl polybutadiene to provide high thermal-oxidative resistance, a characteristic pursued on the premise that thermal oxidation is involved both in the normal abrasion or wear of tire treads and probably in the chain of events leading to blowout failures. Results from the tests demonstrate that the experimental stock provided better heat buildup (hysteresis) and fatigue properties, at least equal wet and dry traction, and greater wear resistance than the state-of-the-art stock.

  13. Elastomeric thermal interface materials with high through-plane thermal conductivity from carbon fiber fillers vertically aligned by electrostatic flocking.

    Science.gov (United States)

    Uetani, Kojiro; Ata, Seisuke; Tomonoh, Shigeki; Yamada, Takeo; Yumura, Motoo; Hata, Kenji

    2014-09-01

    Electrostatic flocking is applied to create an array of aligned carbon fibers from which an elastomeric thermal interface material (TIM) can be fabricated with a high through-plane thermal conductivity of 23.3 W/mK. A high thermal conductivity can be achieved with a significantly low filler level (13.2 wt%). As a result, this material retains the intrinsic properties of the matrix, i.e., elastomeric behavior. PMID:25042211

  14. Unification of reactor elastomeric sealing based on material

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, N.K., E-mail: nksinha@igcar.gov.in [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India); Raj, Baldev [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India)

    2012-02-15

    The unification of elastomeric sealing applications of Indian nuclear reactors based on a few qualified fluoroelastomer/perfluoroelastomer compounds and standardized approaches for finite element analysis (FEA) based design, manufacturing process and antifriction coatings is discussed. It is shown that the advance polymer architecture based Viton{sup Registered-Sign} formulation developed for inflatable seals of 500 MWe Prototype Fast Breeder Reactor (PFBR) and its four basic variations can encompass other sealing applications of PFBR with minimum additional efforts on development and validation. Changing the blend ratio of Viton{sup Registered-Sign} GBL 200S and 600S in inflatable seal formulation could extend its use to Pressurized Heavy Water Reactors (PHWRs). The higher operating temperature of Advanced Heavy Water Reactor (AHWR) seals expands the choice to perfluoroelastomers. FEA based on plane-strain/axisymmetric modeling (with Mooney-Rivlin as the basic constitutive model), seal manufacture by cold feed extrusion and injection molding as well as plasma Teflon-like coating belonging to two variations obtained from the development of inflatable seals provide the necessary standardization for unification. The gains in simplification of design, development and operation of seals along with the enhancements of safety and reliability are expected to be substantial.

  15. Linear dimensional changes in plaster die models using different elastomeric materials

    OpenAIRE

    Jefferson Ricardo Pereira; Karina Yumi Murata; Accácio Lins do Valle; Janaina Salomon Ghizoni; Fábio Kenji Shiratori

    2010-01-01

    Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used...

  16. Biodegradable and Elastomeric Poly(glycerol sebacate) as a Coating Material for Nitinol Bare Stent

    OpenAIRE

    Min Ji Kim; Moon Young Hwang; JiHeung Kim; Dong June Chung

    2014-01-01

    We synthesized and evaluated biodegradable and elastomeric polyesters (poly(glycerol sebacate) (PGS)) using polycondensation between glycerol and sebacic acid to form a cross-linked network structure without using exogenous catalysts. Synthesized materials possess good mechanical properties, elasticity, and surface erosion biodegradation behavior. The tensile strength of the PGS was as high as 0.28?±?0.004?MPa, and Young's modulus was 0.122?±?0.0003?MPa. Elongation was as high a...

  17. Methodology for Evaluating Raw Material Changes to RSRM Elastomeric Insulation Materials

    Science.gov (United States)

    Mildenhall, Scott D.; McCool, Alex (Technical Monitor)

    2001-01-01

    The Reusable Solid Rocket Motor (RSRM) uses asbestos and silicon dioxide filled acrylonitrile butadiene rubber (AS-NBR) as the primary internal insulation to protect the case from heat. During the course of the RSRM Program, several changes have been made to the raw materials and processing of the AS-NBR elastomeric insulation material. These changes have been primarily caused by raw materials becoming obsolete. In addition, some process changes have been implemented that were deemed necessary to improve the quality and consistency of the AS-NBR insulation material. Each change has been evaluated using unique test efforts customized to determine the potential impacts of the specific raw material or process change. Following the evaluations, the various raw material and process changes were successfully implemented with no detectable effect on the performance of the AS-NBR insulation. This paper will discuss some of the raw material and process changes evaluated, the methodology used in designing the unique test plans, and the general evaluation results. A summary of the change history of RSRM AS-NBR internal insulation is also presented.

  18. Predicting the dynamic material constants of Mooney-Rivlin model in broad frequency range for elastomeric components

    Scientific Electronic Library Online (English)

    Kamal, Jahani; Hossein, Mahmoodzade.

    Full Text Available In this paper, dynamic material constants of 2-parameter Mooney-Rivlin model for elastomeric components are identified in broad frequency range. To consider more practical case, an elastomeric engine mount is used as the case study. Finite element model updating technique using Radial Basis Function [...] neural networks is implemented to predict the dynamic material constants. Material constants of 2-parameter Mooney-Rivlin model are obtained by curve fitting on uni-axial stress-strain curve. The initial estimations of the material constants are achieved by using uni-axial tension test data. To ensure of the consistency of dynamic response of a real component, frequency response function of three similar engine mounts are extracted from experimental modal data and average of them used in the procedure. The results showed that this technique can successfully predict dynamic material constants of Mooney-Rivlin model for elastomeric components.

  19. Choice of Elastomeric Material for Buffer Devices of Metallurgical Equipment

    Directory of Open Access Journals (Sweden)

    Firas M.F. Al-Quran

    2012-06-01

    Full Text Available This study sheds light on the materials (elastomers which are used for buffer equipment production. One of the unsolved problems concerning shock absorption is the problem of optimal material choice for the shock absorber. It is the main problem examined in this study. We conclude that the material should be chosen in accordance with such characteristics as energy intensity rate, internal friction and rheological characteristic.

  20. Low-temperature behavior of elastomeric seals. Material property determination for the use in transport and storage casks for radioactive materials

    International Nuclear Information System (INIS)

    Elastomers are used as sealing materials for radioactive waste transport and storage casks. Due to the valid laws and guidelines for these containers the tightness of the elastomeric seals has to be demonstrated for temperature down to -40 C. Therefore the low-temperature behavior of elastomeric seals and the failure mechanism inducing leak rates above the limiting value are of interest. Material properties of elastomeric polymers are significantly temperature dependent, in the low temperature range due to the rubber-glass transition. The measurement of the dynamic storage modulus and the glass transition temperature was performed using dynamic mechanical analysis. Further measurements are necessary to determine the failure temperature of elastomeric seals. The authors show that EPDM is still in the rubber-elastic range at -40 C.

  1. Utilizing stretch-tunable thermochromic elastomeric opal films as novel reversible switchable photonic materials.

    Science.gov (United States)

    Schäfer, Christian G; Lederle, Christina; Zentel, Kristina; Stühn, Bernd; Gallei, Markus

    2014-11-01

    In this work, the preparation of highly thermoresponsive and fully reversible stretch-tunable elastomeric opal films featuring switchable structural colors is reported. Novel particle architectures based on poly(diethylene glycol methylether methacrylate-co-ethyl acrylate) (PDEGMEMA-co-PEA) as shell polymer are synthesized via seeded and stepwise emulsion polymerization protocols. The use of DEGMEMA as comonomer and herein established synthetic strategies leads to monodisperse soft shell particles, which can be directly processed to opal films by using the feasible melt-shear organization technique. Subsequent UV crosslinking strategies open access to mechanically stable and homogeneous elastomeric opal films. The structural colors of the opal films feature mechano- and thermoresponsiveness, which is found to be fully reversible. Optical characterization shows that the combination of both stimuli provokes a photonic bandgap shift of more than 50 nm from 560 nm in the stretched state to 611 nm in the fully swollen state. In addition, versatile colorful patterns onto the colloidal crystal structure are produced by spatial UV-induced crosslinking by using a photomask. This facile approach enables the generation of spatially cross-linked switchable opal films with fascinating optical properties. Herein described strategies for the preparation of PDEGMEMA-containing colloidal architectures, application of the melt-shear ordering technique, and patterned crosslinking of the final opal films open access to novel stimuli-responsive colloidal crystal films, which are expected to be promising materials in the field of security and sensing applications. PMID:25243892

  2. Nuclear power plant accident simulations of gasket materials under simultaneous radiation plus thermal plus mechanical stress conditions

    International Nuclear Information System (INIS)

    In order to probe the response of silicone door gasket materials to a postulated severe accident in an Italian nuclear power plant, compression stress relaxation (CSR) and compression set (CS) measurements were conducted under combined radiation (approximately 6 kGy/h) and temperature (up to 230 degrees C) conditions. By making some reasonable initial assumptions, simplified constant temperature and dose rates were derived that should do a reasonable job of simulating the complex environments for worst-case severe events that combine overall aging plus accidents. Further simplification coupled with thermal-only experiments allowed us to derive thermal-only conditions that can be used to achieve CSR and CS responses similar to those expected from the combined environments that are more difficult to simulate. Although the thermal-only simulations should lead to sealing forces similar to those expected during a severe accident, modulus and density results indicate that significant differences in underlying chemistry are expected for the thermal-only and the combined environment simulations. 15 refs., 31 figs., 15 tabs

  3. Linear dimensional changes in plaster die models using different elastomeric materials

    Directory of Open Access Journals (Sweden)

    Jefferson Ricardo Pereira

    2010-09-01

    Full Text Available Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05 and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm, mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm, polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm. All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.

  4. Behavior of a New Elastomeric material used as polyolefinic geo membrane in waterproofing; Comportamiento de un nuevo material elastomerico utilizado como geomembrana poliolefinica en impermeabilizacion

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, M.; Aguilar, E.; Vara, T. A; Soriano, J.; Garcia, F.; Castillo, F.

    2011-07-01

    Two decades ago that Balsas de Tenerife (BALTEN) and the Centro de Estudios y Experimentacion de Obras Publicas (CEDEX), in its experimental field of the south of the Tenerife Island have installed a series of materials to known their behaviour over time. These products among which was placed over a dozen years ago, on an elastomeric polyolefin. This work presents the performance of this synthetic geo membrane, focusing on the evolution in the time of the tensile properties static puncture, low temperature folding, dynamic impact, joint strength (shear and peeling test), optical microscopy of reflection nd scanning electron microscopy. (Author) 11 refs.

  5. Some basics of EMI gaskets

    International Nuclear Information System (INIS)

    With natural and man-made sources of electromagnetic interference (EMI) ever increasing, and with tighter regulation of military and commercial electronic equipment, design engineers face a growing challenge, both in suppressing and containing electromagnetic emissions generated by equipment, and in shielding components and equipment susceptible to such emissions. The challenge is particularly difficult under extreme environmental conditions and where the equipment must maintain its operational integrity while subjected to radiation from a wide electromagnetic spectrum. The article discusses conductive elastomer gaskets, shielding principles, the principles of conductive gaskets, types of fillers, the influence of vibration on a gasket and the effect of electromagnetic pulses on shielded enclosures. Galvanic corrosion is also of concern in any gasket

  6. Decrease of reaction force of metal gaskets just after initial tightening

    International Nuclear Information System (INIS)

    The decrease of reaction force of some metal gaskets inserted into the test flange at room temperature, 120 C(real cask temperature) and 200 C(accelerated condition) are measured. The reaction forces of metal gaskets in the room temperature have been almost not changed. The reaction force of 120 C and 200 C metal gaskets has decreased according to the temperature increase. After the temperature became stable, the decrease of the reaction force gradually proceeded, this decrease have been as same as previous studies. The bolts of transport and storage casks are usually tightened just after the loading of spent fuels, and then the temperature of metal gaskets at that time is almost the room temperature. The reaction forces of the metal gasket tightened at this condition would be decreased after the temperature increase due to the decay heat of spent fuels. It is confirmed that the loosening of the bolts might be happened if the tightening torque of bolts is not appropriate. It is easy to evaluate that the reaction forces of the metal gasket in storage condition according to Larson-Miller parameter or relaxation of the gasket material, but the decrease of the reaction forces of the metal gasket just after the loading is not able to evaluate by these method. It is necessary to evaluate the reaction forces according to plastic deformation property of the metal gaskets so as to fasten the gaskets safety

  7. Analytical method for distribution of metallic gasket contact stress

    Science.gov (United States)

    Feng, Xiu; Gu, Boqing; Wei, Long; Sun, Jianjun

    2008-11-01

    Metallic gasket seals have been widely used in chemical and petrochemical plants. The failure of sealing system will lead to enormous pecuniary loss, serious environment pollution and personal injury accident. The failure of sealing systems is mostly caused not by the strength of flanges or bolts but by the leakage of the connections. The leakage behavior of bolted flanged connections is related to the gasket contact stress. In particular, the non-uniform distribution of this stress in the radial direction caused by the flange rotational flexibility has a major influence on the tightness of bolted flanged connections. In this paper, based on Warters method and considering the operating pressure, the deformation of the flanges is analyzed theoretically, and the formula for calculating the angle of rotation of the flanges is derived, based on which and the mechanical property of the gasket material, the method for calculating the gasket contact stresses is put forward. The maximum stress at the gasket outer flank calculated by the analytical method is lower than that obtained by numerical simulation, but the mean stresses calculated by the two methods are nearly the same. The analytical method presented in this paper can be used as an engineering method for designing the metallic gasket connections.

  8. Sealing Force Increasing of ACM Gasket through Electron Beam Radiation

    Science.gov (United States)

    dos Santos, D. J.; Batalha, G. F.

    2011-01-01

    Rubber is an engineering material largely used as sealing parts, in form of O-rings, solid gaskets and liquid gaskets, materials applied in liquid state with posterior vulcanization and sealing. Stress relaxation is a rubber characteristic which impacts negatively in such industrial applications (rings and solid gaskets). This work has the purpose to investigate the use of electron beam radiation (EB) as a technology able to decrease the stress relaxation in acrylic rubber (ACM), consequently increasing the sealing capability of this material. ACM samples were irradiated with dose of 100 kGy and 250 kGy, its behavior was comparatively investigated using, dynamic mechanical analysis (DMA) and compression stress relaxation (CSR) experiments. The results obtained by DMA shown an increase of Tg and changes in dynamic mechanical behavior.

  9. Random walks on the Sierpinski Gasket

    OpenAIRE

    Friedberg, R; Martin, O.

    1986-01-01

    The generating functions for random walks on the Sierpinski gasket are computed. For closed walks, we investigate the dependence of these functions on location and the bare hopping parameter. They are continuous on the infinite gasket but not differentiable.

  10. Sierpinski Gaskets for Logic Functions Representation

    OpenAIRE

    Popel, Denis V.; Dani, Anita

    2002-01-01

    This paper introduces a new approach to represent logic functions in the form of Sierpinski Gaskets. The structure of the gasket allows to manipulate with the corresponding logic expression using recursive essence of fractals. Thus, the Sierpinski gasket's pattern has myriad useful properties which can enhance practical features of other graphic representations like decision diagrams. We have covered possible applications of Sierpinski gaskets in logic design and justified o...

  11. Linear dimensional changes in plaster die models using different elastomeric materials

    Scientific Electronic Library Online (English)

    Jefferson Ricardo, Pereira; Karina Yumi, Murata; Accácio Lins do, Valle; Janaina Salomon, Ghizoni; Fábio Kenji, Shiratori.

    2010-09-01

    Full Text Available Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomer [...] ic materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F) were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p

  12. Thermo-mechanical induced deformation simulation studies for metal gaskets for UHV application

    International Nuclear Information System (INIS)

    In vacuum technology, metal gasket seals are extensively employed to achieve a UHV with reduced contamination considering the pressure and temperature variations as it performs a static seal between two stationary members of a mechanical assembly. The optimum sealing is attained over the balancing of the forces effective, which are function of temperature, governs the surface deformation for the metal gasket seal follows into degradation in the leak tightness at elevated temperatures. The prime component exerting the most deformation force over metal gasket seals, gasket seating force is a constant value generated by the bolting of the stationary members of a mechanical assembly. The paper address to metal gasket seals, copper and aluminum, behavior under thermo-mechanical load is analyzed (simulation), with ANSYS platform, workbench. The major concern is to investigate the typical deformation behavior as a function of thermal variation, baking/ cooling. For copper and Aluminum gasket seals, 16mm to 250mm internal diameter, exposed to pre-established gasket seating force under wide temperatures range. The deformation, average and the deformation range, observed to move in a very specific manner and runs to a wide range for a given material and size. The data reported here deserves to be substantial enough to establish the prediction of thermal behavior of metal gasket seals for standardization.

  13. Thermo-mechanical induced deformation simulation studies for metal gaskets for UHV application

    Science.gov (United States)

    Kumar, B. Ramesh; Purohit, S.

    2012-11-01

    In vacuum technology, metal gasket seals are extensively employed to achieve a UHV with reduced contamination considering the pressure and temperature variations as it performs a static seal between two stationary members of a mechanical assembly. The optimum sealing is attained over the balancing of the forces effective, which are function of temperature, governs the surface deformation for the metal gasket seal follows into degradation in the leak tightness at elevated temperatures. The prime component exerting the most deformation force over metal gasket seals, gasket seating force is a constant value generated by the bolting of the stationary members of a mechanical assembly. The paper address to metal gasket seals, copper and aluminum, behavior under thermo-mechanical load is analyzed (simulation), with ANSYS platform, workbench. The major concern is to investigate the typical deformation behavior as a function of thermal variation, baking/ cooling. For copper and Aluminum gasket seals, 16mm to 250mm internal diameter, exposed to pre-established gasket seating force under wide temperatures range. The deformation, average and the deformation range, observed to move in a very specific manner and runs to a wide range for a given material and size. The data reported here deserves to be substantial enough to establish the prediction of thermal behavior of metal gasket seals for standardization.

  14. Sierpinski Gaskets for Logic Functions Representation

    CERN Document Server

    Popel, D V; Popel, Denis V.; Dani, Anita

    2002-01-01

    This paper introduces a new approach to represent logic functions in the form of Sierpinski Gaskets. The structure of the gasket allows to manipulate with the corresponding logic expression using recursive essence of fractals. Thus, the Sierpinski gasket's pattern has myriad useful properties which can enhance practical features of other graphic representations like decision diagrams. We have covered possible applications of Sierpinski gaskets in logic design and justified our assumptions in logic function minimization (both Boolean and multiple-valued cases). The experimental results on benchmarks with advances in the novel structure are considered as well.

  15. Integrated-fin gasket for palm cubic-anvil high pressure apparatus.

    Science.gov (United States)

    Cheng, J-G; Matsubayashi, K; Nagasaki, S; Hisada, A; Hirayama, T; Hedo, M; Kagi, H; Uwatoko, Y

    2014-09-01

    We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression. PMID:25273739

  16. Integrated-fin gasket for palm cubic-anvil high pressure apparatus

    Science.gov (United States)

    Cheng, J.-G.; Matsubayashi, K.; Nagasaki, S.; Hisada, A.; Hirayama, T.; Hedo, M.; Kagi, H.; Uwatoko, Y.

    2014-09-01

    We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression.

  17. Integrated-fin gasket for palm cubic-anvil high pressure apparatus

    International Nuclear Information System (INIS)

    We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression

  18. Reinforcement Of Elastomeric Rubber Using Carbon Fiber Laminates

    OpenAIRE

    Sivaraman R, Roseenid Teresa A.

    2013-01-01

    The Elastomeric rubber is a good energy absorbing device with spring back effect. The effectiveness of any form of rubber depends on its strength and stiffness which cannot be varied beyond a certain limit by using chemical additives alone. So, the elastomeric rubber has to be reinforced by adding a material that is normally stronger and stiffer than rubber. In this paper, the usual problem of vulcanization of rubber was overcome by selecting carbon fibers as the filler material. The unidirec...

  19. Hybrid Methods in Designing Sierpinski Gasket Antennas

    OpenAIRE

    Mudrik Alaydrus

    2010-01-01

    Sierpinki gasket antennas as example of fractal antennas show multiband characteristics. The computer simulation of Sierpinksi gasket monopole with finite ground needs prohibitively large computer memory and more computational time. Hybrid methods consist of surface integral equation method and physical optics or uniform geometrical theory of diffraction should alleviate this computational burdens. The so-called full hybridization of the different methods with modifying the incoming electroma...

  20. Spanning forests on the Sierpinski gasket

    OpenAIRE

    Shu-Chiuan Chang; Lung-Chi Chen

    2008-01-01

    We present the numbers of spanning forests on the Sierpinski gasket $SG_d(n)$ at stage $n$ with dimension $d$ equal to two, three and four, and determine the asymptotic behaviors. The corresponding results on the generalized Sierpinski gasket $SG_{d,b}(n)$ with $d=2$ and $b=3,4$ are obtained. We also derive the upper bounds of the asymptotic growth constants for both $SG_d$ and $SG_{2,b}$.

  1. Zinc oxide nanowire rigid platforms on elastomeric substrates.

    Science.gov (United States)

    Bendall, James S; Graz, Ingrid; Lacour, Stéphanie P

    2011-08-01

    Zinc oxide nanostructured thin films are transparent semiconducting ceramics increasingly used in a wide range of integrated devices. This paper outlines a simple strategy to integrate arrays of zinc oxide nanostructured thin films on elastomeric substrates using templated patterning. The arrays are robust to large uniaxial strains (up to 20% strain), do not fracture, and maintain electrical functionality. The integration of brittle nanostructured semiconducting materials on elastomeric substrates opens promising routes for the manufacture of deformable and stretchable electronics. PMID:21740041

  2. Hybrid Methods in Designing Sierpinski Gasket Antennas

    Directory of Open Access Journals (Sweden)

    Mudrik Alaydrus

    2010-12-01

    Full Text Available Sierpinki gasket antennas as example of fractal antennas show multiband characteristics. The computer simulation of Sierpinksi gasket monopole with finite ground needs prohibitively large computer memory and more computational time. Hybrid methods consist of surface integral equation method and physical optics or uniform geometrical theory of diffraction should alleviate this computational burdens. The so-called full hybridization of the different methods with modifying the incoming electromagnetic waves in case of hybrid method surface integral equation method and physical optics and modification of the Greens function for hybrid method surface integral equation method and uniform geometrical theory of diffraction plays the central role in the observation. Comparison between results of different methods are given and also measurements of three Sierpinksi gasket antennas. The multiband characteristics of the antennas still can be seen with some reduction and enhancement of resonances.

  3. Group structure of the Sierpinski gasket

    International Nuclear Information System (INIS)

    The group structure of the object with non-integer dimension is investigated. It is shown that some extended group based on the point group of the substructure of the fractal is required. The extended group for the Sierpinski gasket, i.e. the fractal with dimension D approx.= 1.58, is based on the permutation group s3. This group of the Sierpinski gasket is a hierarchical and permutational one. It is shown that such a hierarchical structure of the group is caused by the self-similarity of the investigated fractal. (author)

  4. Properties and degradation of the gasket component of a proton exchange membrane fuel cell--a review.

    Science.gov (United States)

    Basuli, Utpal; Jose, Jobin; Lee, Ran Hee; Yoo, Yong Hwan; Jeong, Kwang-Un; Ahn, Jou-Hyeon; Nah, Changwoon

    2012-10-01

    Proton exchange membrane (PEM) fuel cell stack requires gaskets and seals in each cell to keep the reactant gases within their respective regions. Gasket performance is integral to the successful long-term operation of a fuel cell stack. This review focuses on properties, performance and degradation mechanisms of the different polymer gasket materials used in PEM fuel cell under normal operating conditions. The different degradation mechanisms and their corresponding representative mitigation strategies are also presented here. Summary of various properties of elastomers and their advantages and disadvantages in fuel cell'environment are presented. By considering the level of chemical degradation, mechanical properties and cost effectiveness, it can be proposed that EPDM is one of the best choices for gasket material in PEM fuel cell. Finally, the challenges that remain in using rubber component as in PEM fuel cell, as well as the prospects for exploiting them in the future are discussed. PMID:23421125

  5. Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Ethanol-blended Gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Kass, Michael D [ORNL; Pawel, Steven J [ORNL; Theiss, Timothy J [ORNL; Janke, Christopher James [ORNL

    2012-07-01

    In 2008 Oak Ridge National Laboratory began a series of experiments to evaluate the compatibility of fueling infrastructure materials with intermediate levels of ethanol-blended gasoline. Initially, the focus was elastomers, metals, and sealants, and the test fuels were Fuel C, CE10a, CE17a and CE25a. The results of these studies were published in 2010. Follow-on studies were performed with an emphasis on plastic (thermoplastic and thermoset) materials used in underground storage and dispenser systems. These materials were exposed to test fuels of Fuel C and CE25a. Upon completion of this effort, it was felt that additional compatibility data with higher ethanol blends was needed and another round of experimentation was performed on elastomers, metals, and plastics with CE50a and CE85a test fuels. Compatibility of polymers typically relates to the solubility of the solid polymer with a solvent. It can also mean susceptibility to chemical attack, but the polymers and test fuels evaluated in this study are not considered to be chemically reactive with each other. Solubility in polymers is typically assessed by measuring the volume swell of the polymer exposed to the solvent of interest. Elastomers are a class of polymers that are predominantly used as seals, and most o-ring and seal manufacturers provide compatibility tables of their products with various solvents including ethanol, toluene, and isooctane, which are components of aggressive oxygenated gasoline as described by the Society of Automotive Engineers (SAE) J1681. These tables include a ranking based on the level of volume swell in the elastomer associated with exposure to a particular solvent. Swell is usually accompanied by a decrease in hardness (softening) that also affects performance. For seal applications, shrinkage of the elastomer upon drying is also a critical parameter since a contraction of volume can conceivably enable leakage to occur. Shrinkage is also indicative of the removal of one or more components of the elastomers (by the solvent). This extraction of additives can negatively change the properties of the elastomer, leading to reduced performance and durability. For a seal application, some level of volume swell is acceptable, since the expansion will serve to maintain a seal. However, the acceptable level of swell is dependent on the particular application of the elastomer product. It is known that excessive swell can lead to unacceptable extrusion of the elastomer beyond the sealed interface, where it becomes susceptible to damage. Also, since high swell is indicative of high solubility, there is a heightened potential for fluid to seep through the seal and into the environment. Plastics, on the other hand, are used primarily in structural applications, such as solid components, including piping and fluid containment. Volume change, especially in a rigid system, will create internal stresses that may negatively affect performance. In order to better understand and predict the compatibility for a given polymer type and fuel composition, an analysis based on Hansen solubility theory was performed for each plastic and elastomer material. From this study, the solubility distance was calculated for each polymer material and test fuel combination. Using the calculated solubility distance, the ethanol concentration associated with peak swell and overall extent of swell can be predicted for each polymer. The bulk of the material discussion centers on the plastic materials, and their compatibility with Fuel C, CE25a, CE50a, and CE85a. The next section of this paper focuses on the elastomer compatibility with the higher ethanol concentrations with comparison to results obtained previously for the lower ethanol levels. The elastomers were identical to those used in the earlier study. Hansen solubility theory is also applied to the elastomers to provide added interpretation of the results. The final section summarizes the performance of the metal coupons.

  6. The Hausdorff dimension of the CLE gasket

    CERN Document Server

    Miller, Jason; Wilson, David B

    2012-01-01

    The conformal loop ensemble CLE_kappa is the canonical conformally invariant probability measure on non-crossing loops in a proper simply connected domain in the complex plane. The parameter kappa varies between 8/3 and 8; CLE_{8/3} is empty while CLE_8 is a single space-filling loop. In this work we study the geometry of the CLE gasket, the set of points not surrounded by any loop of the CLE. We show that the almost sure Hausdorff dimension of the gasket is bounded from below by 2-(8-kappa)(3 kappa-8)/(32 kappa) when 4gasket dimension for all values of kappa for which it is defined. The dimension agrees with the prediction of Duplantier-Saleur (1989) for the FK gasket.

  7. Elastomeric substrates with embedded stiff platforms for stretchable electronics

    Science.gov (United States)

    Romeo, Alessia; Liu, Qihan; Suo, Zhigang; Lacour, Stéphanie P.

    2013-04-01

    Stretchable electronics typically integrate hard, functional materials on soft substrates. Here we report on engineered elastomeric substrates designed to host stretchable circuitry. Regions of a stiff material, patterned using photolithography, are embedded within a soft elastomer leaving a smooth surface. We present the associated design rules to produce stretchable circuits based on experimental as well as modeling data. We demonstrate our approach with thin-film electronic materials. The "customized" elastomeric substrates may also be used as a generic elastic substrate for stretchable circuits prepared with alternative technologies, such as transfer-printing of inorganic, thinned devices.

  8. COMPARACIÓN DE MODELOS DINÁMICOS DEL COMPORTAMIENTO DE UN MATERIAL ELASTOMÉRICO BAJO TASAS DE DEFORMACIÓN MEDIAS / COMPARISON OF AN ELASTOMERIC MATERIAL BEHAVIOR’S DYNAMIC MODELS UNDER INTERMEDIATE STRAIN RATES

    Scientific Electronic Library Online (English)

    Andrés Felipe, Ramírez; Luis Ernesto, Muñoz.

    2014-06-01

    Full Text Available El presente trabajo estudia dos modelos dinámicos del comportamiento de un material elastomérico cuando se somete a tasas de deformación medias. Los modelos a estudiar fueron los modelos constitutivos de Maxwell y Cowper & Symonds. Se realizó una comparación analítica entre los dos modelos. Se tomar [...] on resultados de pruebas de caracterización dinámica de materiales y se identificaron los parámetros de cada modelo mediante un proceso de identificación multi-variable. Se estudió el nivel de representatividad obtenido en los dos casos, analizando los resultados de la identificación multivariable. Abstract in english This paper studies two dynamic models of an elastomeric material behavior when it is subjected to intermediate strain rates. The studied models were the constitutive Maxwell model and the constitutive Cowper & Symonds model. An analytical comparison of each model was performed. Test results were tak [...] en from a dynamic material’s characterization and the parameters of each model were identified through a process of multi-variable identification. The level of representation obtained in both cases was studied, in order to analyze the analytical comparison with the results of the multi-variable identification.

  9. Effect of Commonly Used Beverage, Soft Drink, and Mouthwash on Force Delivered by Elastomeric Chain: A Comparative In Vitro Study

    OpenAIRE

    Kumar, Kiran; Shetty, Sharath; Krithika, M J; Cyriac, Bobby

    2014-01-01

    Background: The objective was to evaluate and compare the effect of Coca-Cola®, tea, Listerine® mouthwash on the force delivered by elastomeric chain in vitro. Materials and Methods: Four specimen groups (distilled water, Coca-Cola®, tea, Listerine® mouthwash) with a total sample size of 480 specimens. A specimen is described as a four link grey close elastomeric chain. Jigs, each with a series of pins set 25 mm apart, was used to hold stretched elastomeric chains ...

  10. Actuating dielectric elastomers in pure shear deformation by elastomeric conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yin; Chen, Baohong; Zhou, Jinxiong, E-mail: jxzhouxx@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures and School of Aerospace, Xi’an Jiaotong University, Xi' an 710049 (China); Bai, Yuanyuan; Wang, Hong [Electronic Materials Research Laboratory, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-02-10

    Pure shear experiments are commonly used to characterize dielectric elastomer (DE) material properties and to evaluate DE actuator/generator performance. It is increasingly important for many applications to replace conventional carbon grease electrodes with stretchable elastomeric conductors. We formulate a theory for DE with elastomeric conductors, synthesize transparent hydrogel as ionic conductors, and measure actuation of DE in pure shear deformation. Maximum 67% actuation strain is demonstrated. The theory agrees well with our measurement and also correlates well with reported experiments on DE with electronic conductors.

  11. In situ evaluation of orthodontic elastomeric chains

    Scientific Electronic Library Online (English)

    Carolina, Baratieri; Cláudia Trindade, Mattos; Matheus, Alves Jr; Thiago Chon Leon, Lau; Lincoln Issamu, Nojima; Margareth Maria Gomes de, Souza; Monica Tirre, Araujo; Matilde da Cunha Gonçalves, Nojima.

    Full Text Available A hipótese testada foi que a exposição dos elásticos em cadeia ao meio bucal altera sua força de tensão. Portanto, o objetivo deste estudo foi avaliar o comportamento, in situ, de diferentes cadeias elastoméricas quando tensionadas durante 3 semanas. Três tipos de elásticos em cadeia Plastic Chain ( [...] PC), Memory Chain (MC) e Super Slick Chain (SSC) foram inseridos aleatoriamente em 3 dos quadrantes de 13 pacientes com distância fixa de 16 mm e força inicial de 180 g. Foi realizado ensaio de tração em uma máquina de ensaio universal EMIC nos seguintes intervalos: inicial, 1 h, 24 h, 1 semana, 2 semanas e 3 semanas. O teste ANOVA a dois critérios foi aplicado para verificar a influência do material e do tempo na degradação da força. Subsequentemente, foi utilizado o teste ANOVA a um critério e pós-teste de Tukey para identificar diferenças estatísticas (p Abstract in english The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) [...] and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

  12. Reinforcement Of Elastomeric Rubber Using Carbon Fiber Laminates

    Directory of Open Access Journals (Sweden)

    SIVARAMAN R, ROSEENID TERESA A, SIDDANTH S

    2013-07-01

    Full Text Available The Elastomeric rubber is a good energy absorbing device with spring back effect. The effectiveness of any form of rubber depends on its strength and stiffness which cannot be varied beyond a certain limit by using chemical additives alone. So, the elastomeric rubber has to be reinforced by adding a material that is normally stronger and stiffer than rubber. In this paper, the usual problem of vulcanization of rubber was overcome by selecting carbon fibers as the filler material. The unidirectional property of carbon fibers gives it the ability to be oriented in any desired direction, thus imparting required properties. The material was modeled as a composite beam structure initially using the ANSYS software and dynamic analysis was performed to find out the fundamental mode of vibration. A Test specimen was then fabricated according to ASTM standards and experimental investigations were carried out. Mechanical properties of the material such as tensile strength, compression strength, flexure strength and impact strength were obtained from the experimental investigation. The test results of the carbon fiber laminated elastomeric rubber were then compared with ordinary elastomeric rubber with usual additives and it was found to be superior in all aspects.

  13. Gasket sealing performance simulation during cycling operation condition

    International Nuclear Information System (INIS)

    The Steam Generators used in CANDU Nuclear Power Plants employ a primary-side obround manway design with two cover plates on each side of the opening. The sealing action against the high pressure primary side fluid is achieved by a spiral wound gasket installed in a groove in both inner and outer cover. The inner cover gasket will be initially pre stressed by the stud preload and by the internal pressure. The gasket in the outer cover will be initially pre stressed with the stud preload and unloaded during the application of the internal pressure. During the start up and shut down of the unit the temperature of the metal parts will change. This change in metal temperature has a significant effect on the gasket contact pressure and hence leak tightness. Because of the double gasket design, evaluation of the gasket pressure and hence leak tightness is only possible by using Finite Element (FE) analysis. This paper will investigate on a generic CANDU type primary manway the change in gasket contact pressure during the transient operation of the unit (heat up, start up, normal operation, shut down and cooled down) that will include the complex interaction between the manway components. The effect of repeated transient operation on the gasket contact pressure will also be investigated. During transient operation of the units (heat up, start up, operation, shut down and cool down) a complex interaction between the manway components occurs, which not only causes time-varying gasket contact pressure but also induces a non-uniform gasket contact pressure along the gasket width. As a result, the leak tightness of the joint may be affected. The effect of different stud preloads on the gasket contact pressure during transient operation is investigated by the 3D FE Analysis of a primary-side obround manway of CANDU's steam generator. The results are used to justify the seal performance of the manway structure under conditions of different stud pretension loads. The distribution of gasket contact pressure can also be used to evaluate the potential of leakage of any damaged gasket surface. The gasket surface can be damaged during manway disassembly and often needs to be evaluated to decide if a repair is needed or not. (author)

  14. The Hausdorff dimension of the CLE gasket

    OpenAIRE

    Miller, Jason; Sun, Nike; Wilson, David B.

    2012-01-01

    The conformal loop ensemble $\\mathrm{CLE}_{\\kappa}$ is the canonical conformally invariant probability measure on noncrossing loops in a proper simply connected domain in the complex plane. The parameter $\\kappa$ varies between $8/3$ and $8$; $\\mathrm{CLE}_{8/3}$ is empty while $\\mathrm {CLE}_8$ is a single space-filling loop. In this work, we study the geometry of the $\\mathrm{CLE}$ gasket, the set of points not surrounded by any loop of the $\\mathrm{CLE}$. We show that the...

  15. Fluid sealing of static gasketed joints

    International Nuclear Information System (INIS)

    This book brings together the points of view of searchers, gaskets and pressure vessels manufacturers and users concerning fluid sealing problems. The tightness parameter is now considered as a failure criterion and, thus, some aspects concerning the conceiving and building of pressure vessels and apparatuses (and more particularly the bolted assemblies with gaskets), were questioned in order to improve their safety and reliability. New calculation methods, including the tightness parameter are now proposed to standardization authorities. The preoccupations concerning the environmental protection have led the legislative authorities to fix admissible levels of leakage for different industrial components, in particular for petrochemical uses. Strict regulations were enforced in the USA (Clean Air Act) and in Germany (TA Luft). Four papers out of 39 presented in this book of proceedings deal with the control and prevention of leakage in petrochemical refineries, gas production plants and storage systems, and were selected for ETDE. Four other papers dealing with leakage problems in nuclear facilities and high energy physics instruments were selected for INIS. (J.S.)

  16. Effect of storage period on the accuracy of elastomeric impressions

    OpenAIRE

    Eduardo Batista Franco; Leonardo Fernandes da Cunha; Ana Raquel Benetti

    2007-01-01

    AIMS: To investigate the effect of the storage period on the accuracy of recently developed elastomeric materials. METHODS: Simultaneous impressions of a steel die were taken using a polyether (I: Impregum Soft Heavy and Light body, 3M ESPE) and vinyl polysiloxane (P: Perfectim Blue Velvet and Flexi-Velvet, J.Morita). The trays were loaded with the heavy-bodied impression materials while the light-bodied impression materials were simultaneously spread on the steel die. The impressions were po...

  17. Modeling friction phenomena and elastomeric dampers in multibody dynamics analysis

    Science.gov (United States)

    Ju, Changkuan

    The first part of this dissertation focuses on the development, implementation and validation of models that capture the behavior of joints in a realistic manner. These models are presented within the framework of finite element based, nonlinear multibody dynamics formulations that ensure unconditional nonlinear stability of the computation for complex systems of arbitrary topology. The proposed approach can be divided into three parts. First, the joint configuration: this purely kinematic part deals with the description of the configuration of the joint and the evaluation of the relative distance and relative tangential velocity between the contacting bodies. Second, the contact conditions: in most cases, contact at the joint is of an intermittent nature. The enforcement of the unilateral contact condition is a critical aspect of the computational procedure. And finally, the contact forces: this last part deals with the evaluation of the forces that arise at the interface between contacting bodies. The advantage of the proposed approach is that the three parts of the problem can be formulated and implemented independently. Many articulated rotor helicopters use hydraulic dampers, which provide high levels of damping but are also associated with high maintenance costs and difficulties in evaluating their conditions due to the presence of seals, lubricants and numerous moving parts, all operating in a rotating frame. To avoid problems associated with hydraulic dampers, the industry is now switching to elastomeric lead-lag dampers that feature simpler mechanical design, lower part count, and result in "dry" rotors. However, the design of robust elastomeric dampers is hampered by the lack of reliable analytical tools that can be used to predict their damping behavior in the presence of large multi-frequency motions experienced by the rotor and thus the damper. The second part of this dissertation focuses on the development of an elastomeric damper model which predicts the behavior of the elastomeric damper based on a continuum mechanics approach: the configuration of the damper is modeled using a finite element approach, and material behavior is represented by a set of nonlinear constitutive laws and material parameters. The validated finite element model of the elastomeric damper is then coupled with a comprehensive, multibody dynamics analysis code to predict the behavior of complex systems featuring elastomeric components, for example, rotorcraft with elastomeric lead-lag dampers.

  18. Development Of Remote Hanford Connector Gasket Replacement Tooling For DWPF

    International Nuclear Information System (INIS)

    The Defense Waste Processing Facility (DWPF) requested the Savannah River National Laboratory (SRNL) to develop tooling and equipment to remotely replace gaskets in mechanical Hanford connectors to reduce personnel radiation exposure as compared to the current hands-on method. It is also expected that radiation levels will continually increase with future waste streams. The equipment is operated in the Remote Equipment Decontamination Cell (REDC), which is equipped with compressed air, two master-slave manipulators (MSM's) and an electro-mechanical manipulator (EMM) arm for operation of the remote tools. The REDC does not provide access to electrical power, so the equipment must be manually or pneumatically operated. The MSM's have a load limit at full extension of ten pounds, which limited the weight of the installation tool. In order to remotely replace Hanford connector gaskets several operations must be performed remotely, these include: removal of the spent gasket and retaining ring (retaining ring is also called snap ring), loading the new snap ring and gasket into the installation tool and installation of the new gasket into the Hanford connector. SRNL developed and tested tools that successfully perform all of the necessary tasks. Removal of snap rings from horizontal and vertical connectors is performed by separate air actuated retaining ring removal tools and is manipulated in the cell by the MSM. In order install a new gasket, the snap ring loader is used tnew gasket, the snap ring loader is used to load a new snap ring into a groove in the gasket installation tool. A new gasket is placed on the installation tool and retained by custom springs. An MSM lifts the installation tool and presses the mounted gasket against the connector block. Once the installation tool is in position, the gasket and snap ring are installed onto the connector by pneumatic actuation. All of the tools are located on a custom work table with a pneumatic valve station that directs compressed air to the desired tool and vents the tools as needed. Extensive testing of tooling operation was performed in the DWPF manipulator repair shop. This testing allowed the operators to gain confidence before the equipment was exposed to radioactive contamination. The testing also led to multiple design improvements. On July 17 and 29, 2008 the Remote Gasket Replacement Tooling was successfully demonstrated in the REDC at the DWPF of The Savannah River Site.

  19. Thermomechanical behavior of shape memory elastomeric composites

    Science.gov (United States)

    Ge, Qi; Luo, Xiaofan; Rodriguez, Erika D.; Zhang, Xiao; Mather, Patrick T.; Dunn, Martin L.; Qi, H. Jerry

    2012-01-01

    Shape memory polymers (SMPs) can fix a temporary shape and recover their permanent shape in response to environmental stimuli such as heat, electricity, or irradiation. Most thermally activated SMPs use the macromolecular chain mobility change around the glass transition temperature ( Tg) to achieve the shape memory (SM) effects. During this process, the stiffness of the material typically changes by three orders of magnitude. Recently, a composite materials approach was developed to achieve thermally activated shape memory effect where the material exhibits elastomeric response in both the temporary and the recovered configurations. These shape memory elastomeric composites (SMECs) consist of an elastomeric matrix reinforced by a semicrystalline polymer fiber network. The matrix provides background rubber elasticity while the fiber network can transform between solid crystals and melt phases over the operative temperature range. As such it serves as a reversible "switching phase" that enables shape fixing and recovery. Shape memory elastomeric composites provide a new paradigm for the development of a wide array of active polymer composites that utilize the melt-crystal transition to achieve the shape memory effect. This potentially allows for material systems with much simpler chemistries than most shape memory polymers and thus can facilitate more rapid material development and insertion. It is therefore important to understand the thermomechanical behavior and to develop corresponding material models. In this paper, a 3D finite-deformation constitutive modeling framework was developed to describe the thermomechanical behavior of SMEC. The model is phenomenological, although inspired by micromechanical considerations of load transfer between the matrix and fiber phases of a composite system. It treats the matrix as an elastomer and the fibers as a complex solid that itself is an aggregate of melt and crystal phases that evolve from one to the other during a temperature change. As such, the composite consists of an elastomer reinforced by a soft liquid at high temperature and a stiff solid at low temperature. The model includes a kinetic description of the non-isothermal crystallization and melting of the fibers during a temperature change. As the fibers transform from melt to crystal during cooling it is assumed that new crystals are formed in an undeformed state, which requires careful tracking of the kinematics of the evolving phases which comes at a significant computational cost. In order to improve the computational efficiency, an effective phase model (EPM) is adopted to treat the evolving crystal phases as an effective medium. A suite of careful thermomechanical experiments with a SMEC was carried out to calibrate various model parameters, and then to demonstrate the ability of the model to accurately capture the shape memory behavior of the SMEC system during complex thermomechanical loading scenarios. The model also identifies the effects of microstructural design parameters such as the fiber volume fraction.

  20. REVIEW OF ENERGY EFFICIENCY OF REFRIGERATOR/FREEZER GASKETS

    Science.gov (United States)

    The report gives results of an investigation of the significance of heat leakage through gaskets in household refrigerator/freezers, explores different design features, and suggests further study if necessary. he report gives results of an extensive literature review, interviews ...

  1. Experimental Study on the Ultimate Shear Performance of Elastomeric Bearings of Doublefold Elastomeric Layer

    Directory of Open Access Journals (Sweden)

    Hyejin Yoon

    2013-01-01

    Full Text Available The elastomeric bearings shall not fail nor degrade the durability of the bridge due to the loss of its properties during its service life. Since the elastomeric bearings can be used in the seismic design complementarily to seismic devices, even if it is not a seismic isolator, they particularly should secure high shear performance. For elastomeric bearings to behave monolithically, the internal rubber which is located between the steel plates should be single rubber layer. In this study, a series of elastomeric bearings were fabricated and ultimate shear performance was investigated. Some specimens are of single elastomeric layer, the other are of doublefold elastomeric layer. Shear fatigue tests and ultimate shear tests were carried out. Tests results show that the elastomeric bearings whose internal rubber layer is formed by agglomeration of several rubber pads is likely to experience significant loss of its shear performance or early failure.

  2. Rheo-Optics and X-Ray Scattering Study of Elastomeric Polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Pople, John A

    2001-10-16

    Elastomeric polypropylenes (ePP) have been known since the early history of polypropylene. Elastomeric polypropylenes were first synthesized by Natta using heterogeneous Ziegler-type catalysts; he attributed the elastomeric behavior to their low crystallinity and stereoisomer blocks consisting of alternating isotactic crystalline and atactic amorphous segments. Subsequent to Natta's work, there have been a number of reports of the production of related materials produced with different catalysts, with notable advances by Collette, Chien, and Collins. Recently, we reported that metallocene catalysts derived from 2-arylindene ligands produce elastomeric polypropylenes which can be separated into fractions differing in tacticity and crystallinity. Studies of the elastomeric polypropylenes using rheological and optical-polarimetry methods reveal evidence of a physical network in contrast to the blend of atactic and isotactic fractions. Dynamic infrared (IR) polarimetry studies provide evidence of cocrystallization of solvent fractions of the materials subjected to step-shear flows. In the current study, we examine the tensile flow properties of elastomeric polypropylene and its solvent fractions derived from 2-arylindene metallocenes catalysts. The origin of tensile set is studied by simultaneously measuring the tensile stress and optical birefringence. The birefringence follows the flow-induced anisotropy arising from amorphous chain orientation and oriented crystallites. Wide Angle and Small Angle X-ray Scattering (WAXS and SAXS, respectively) were performed to investigate the crystallite orientation as well as strain-induced crystallinity.

  3. Elastomeric urethane coatings for the protection of polyurethane foam insulation

    International Nuclear Information System (INIS)

    Spray applied urethane foam and coatings is a unique, economically effective, insulational system. The system is essentially comprised of polyurethane foam and a protective urethane barrier coating. It is this protective coating that ultimately determines the longevity of the system. Of the various coating materials available, the elastomeric urethane coatings offer the best overall performance standards. The long term benefit of this system can be realized if the Specifying Engineer is fully aware of the requirements of the system

  4. The comparison of System 1000 analysis and type testing for neoprene gasket environmental qualification

    International Nuclear Information System (INIS)

    The typical environmental qualification is to ensure that equipment will operate on demand to meet system performance requirements during normal and abnormal service conditions. There are four environmental qualification methods, type testing, operating experience, analysis and combined method. Generally, the American EQ do not contain the mechanical equipment like pumps and valves in their EQ equipment list because their EQ standard 10CFR50.49 limits EQ equipment as electrical equipment. On the other hand, Canadian EQ contain the mechanical equipment like pumps and valves in their EQ components list, Canadians usually call American 'equipment' as 'components', because their EQ standard CSA N290.13-05 do not limits EQ equipment as electrical equipment. System 1000 program is typical Canadian EQ analysis method using mathematical modeling and comparison with established engineering information and manufacturers' data. Most of Canadian nuclear power utilities like NB Power, Hydro Quebec and OPG use the System 1000 program to evaluate the design life for their EQ components. To qualify a pump, I had to list all the non-metallic parts in the pump and found there are lots of gaskets made by neoprene material. I tried to qualify these neoprene gaskets by analysis using System 1000 program and by type testing. In this paper, I'd like to introduce the qualification results of neoprene gasket both type testing and analysis using System 1000 program 1000 program

  5. Coevolutionary extremal dynamics on gasket fractal

    International Nuclear Information System (INIS)

    We considered a Bak-Sneppen model on a Sierpinski gasket fractal. We calculated the avalanche size distribution and the distribution of distances between subsequent minimal sites. To observe the temporal correlations of the avalanche, we estimated the return time distribution, the first-return time, and the all-return time distribution. The avalanche size distribution follows the power law, P(s)?s-?, with the exponent ?=1.004(7). The distribution of jumping sites also follows the power law, P(r)?r-?, with the critical exponent ?=4.12(4). We observe the periodic oscillation of the distribution of the jumping distances which originated from the jumps of the level when the minimal site crosses the stage of the fractal. The first-return time distribution shows the power law, Pf(t)?t-?f, with the critical exponent ?f=1.418(7). The all-return time distribution is also characterized by the power law, Pa(t)?t-?a, with the exponent ?a=0.522(4). The exponents of the return time satisfy the scaling relation ?f+?a=2 for ?f?2.

  6. Statistical study of static gasket conductance

    International Nuclear Information System (INIS)

    This work is motivated by tightness technological problems associated with metallic gasket. The objective is a better understanding of leakage mechanisms, through the development of new computational tools. In this study, the aperture field between two rough surfaces in contact is described by a short correlated isotropic random Gaussian process. The system is studied as a set of independent elementary surfaces. Joint conductances are evaluated from a statistical study on those elementary surfaces. A computational code is developed using a network approach based on lubrication theory estimation of local conductances. The global conductance computation becomes analogous to an electrical problem for which the resistances are distributed on a random network. The network is built from the identification of the aperture field critical points. Maxima are linked through saddle points. Bond conductances are estimated at the aperture field saddle points. First, a purely plastic model of deformations is considered. Near percolation threshold the conductances display a power behaviour. Far from percolation threshold, numerical results are favourably compared with an effective medium approximation. Secondly, we study the impact of elastic deformations. A computational code based on Boussinesq approximation is coupled to the network approach. The results indicate a significant impact of elastic deformations on conductances. Finally, the network approach is adapted to simulate quasi-static drainage thanks to a classical invasion percolation algorithm. A good comparison between previous experiments and numerical predictions is obtained. (author)

  7. Energy dissipation in elastomeric isolators subjected to seismic forces

    International Nuclear Information System (INIS)

    In this paper, a detailed analysis is presented to elucidate thermal effects in elastomeric seismic isolators. Using the material properties of elastomers and the time history of typical seismic events, it is shown that a properly designed base structure provides effective heat transfer and limits temperature rise in the elastomer. The frequency-dependent material properties are a key factor in designing the base structure for maximum effectiveness. When thermal effects are considered, the material properties of the elastomer(s) do not change with temperature. Thus, the isolator material do not degrade during a prolonged seismic event and effectiveness is thereby optimized

  8. Reduction of molecular gas diffusion through gaskets in leaf gas exchange cuvettes by leaf?mediated pores

    DEFF Research Database (Denmark)

    Boesgaard, Kristine Stove; Mikkelsen, Teis NØrgaard

    2013-01-01

    There is an ongoing debate on how to correct leaf gas exchange measurements for the unavoidable diffusion leakage that occurs when measurements are done in non?ambient CO2 concentrations. In this study, we present a theory on how the CO2 diffusion gradient over the gasket is affected by leaf?mediated pores (LMP) and how LMP reduce diffusive exchange across the gaskets. Recent discussions have so far neglected the processes in the quasi?laminar boundary layer around the gasket. Counter intuitively, LMP reduce the leakage through gaskets, which can be explained by assuming that the boundary layer at the exterior of the cuvette is enriched with air from the inside of the cuvette. The effect can thus be reduced by reducing the boundary layer thickness. The theory clarifies conflicting results from earlier studies. We developed leaf adaptor frames that eliminate LMP during measurements on delicate plant material such as grass leaves with circular cross section, and the effectiveness is shown with respiration measurements on a harp of Deschampsia flexuosa leaves. We conclude that the best solution for measurements with portable photosynthesis systems is to avoid LMP rather than trying to correct for the effects.

  9. Resilin: protein-based elastomeric biomaterials.

    Science.gov (United States)

    Su, Renay S-C; Kim, Yeji; Liu, Julie C

    2014-04-01

    Resilin is an elastomeric protein found in insect cuticles and is remarkable for its high strain, low stiffness, and high resilience. Since the first resilin sequence was identified in Drosophilia melanogaster (fruit fly), researchers have utilized molecular cloning techniques to construct resilin-based proteins for a number of different applications. In addition to exhibiting the superior mechanical properties of resilin, resilin-based proteins are autofluorescent, display self-assembly properties, and undergo phase transitions in response to temperature. These properties have potential application in designing biosensors or environmentally responsive materials for use in tissue engineering or drug delivery. Furthermore, the capability of resilin-based biomaterials has been expanded by designing proteins that include both resilin-based sequences and bioactive domains such as cell-adhesion or matrix metalloproteinase sequences. These new materials maintain the superior mechanical and physical properties of resilin and also have the added benefit of controlling cell response. Because the mechanical and biological properties can be tuned through protein engineering, a wide range of properties can be achieved for tissue engineering applications including muscles, vocal folds, cardiovascular tissues, and cartilage. PMID:23831198

  10. Combination spacer and gasket provides effective static seal

    Science.gov (United States)

    Jones, F. B.

    1966-01-01

    Closely machined steel ring having narrow sealing lands on both faces and a thin coating of a commercially available halocarbon polymer combines the functions of a spacer and static seal ring or gasket having a minimum of potential leak paths. The device is effective over a wide range of temperatures down to minus 423 deg F and at pressure up to 180 psig.

  11. Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

    Scientific Electronic Library Online (English)

    Matheus Melo, Pithon; Caio Souza, Ferraz; Francine Cristina Silva, Rosa; Luciano Pereira, Rosa.

    2015-06-01

    Full Text Available OBJETIVO: verificar os efeitos de diferentes métodos de esterilização/desinfecção nas propriedades mecânicas de elásticos ortodônticos em cadeia. MÉTODOS: segmentos de elástico em cadeia com 5 elos cada foram enviados para esterilização em radiação gama com cobalto 60 (20 KGy). Após esterilização, [...] esses foram contaminados com amostras clínicas de Streptococcus mutans. Passado esse período, foram submetidos aos testes de esterilização/desinfecção por diferentes métodos, formando seis grupos de estudo, assim denominados: Grupo 1 (controle - sem ter sido contaminado), Grupo 2 (álcool 70°GL), Grupo 3 (autoclave), Grupo 4 (ultravioleta), Grupo 5 (ácido peracético) e Grupo 6 (glutaraldeído). Após esterilização/desinfecção, avaliou-se a efetividade desses métodos, por meio de contagem de unidades formadoras de colônias por mL (UFC/mL), e as propriedades mecânicas desses materiais. Utilizou-se o teste t de Student para avaliar o número de UFC, além do ANOVA e, posteriormente, do teste de Tukey para avaliação da força. RESULTADOS: verificou-se que o ultravioleta não obteve eficácia total quanto à esterilização. E não ocorreu perda das propriedades mecânicas dos elásticos, com os diferentes métodos de esterilização utilizados (p > 0,05). CONCLUSÃO: o controle biológico de elásticos em cadeia não interfere nas suas propriedades mecânicas. Abstract in english OBJECTIVE: To investigate the effects of different sterilization/disinfection methods on the mechanical properties of orthodontic elastomeric chains. METHODS: Segments of elastomeric chains with 5 links each were sent for sterilization by cobalt 60 (Co60) (20 KGy) gamma ray technology. After the pr [...] ocedure, the elastomeric chains were contaminated with clinical samples of Streptococcus mutans. Subsequently, the elastomeric chains were submitted to sterilization/disinfection tests carried out by means of different methods, forming six study groups, as follows: Group 1 (control - without contamination), Group 2 (70°GL alcohol), Group 3 (autoclave), Group 4 (ultraviolet), Group 5 (peracetic acid) and Group 6 (glutaraldehyde). After sterilization/disinfection, the effectiveness of these methods, by Colony forming units per mL (CFU/mL), and the mechanical properties of the material were assessed. Student's t-test was used to assess the number of CFUs while ANOVA and Tukey's test were used to assess elastic strength. RESULTS: Ultraviolet treatment was not completely effective for sterilization. No loss of mechanical properties occurred with the use of the different sterilization methods (p > 0.05). CONCLUSION: Biological control of elastomeric chains does not affect their mechanical properties.

  12. Tribological properties and morphology of bimodal elastomeric nitrile butadiene rubber networks

    International Nuclear Information System (INIS)

    Highlights: • Bimodal elastomeric NBR as a new material was developed. • The structure of bimodal elastomeric NBR networks was determined. • The relationship between structure and mechanical properties was investigated. • The tribological properties and mechanisms of bimodal NBR were analyzed. • The benefits of bimodal NBR in the field of tribology were discussed. - Abstract: Bimodal nitrile butadiene rubber (NBR) was examined in this study. The molecular structure was determined by dynamic mechanical analysis and transmission electron microscopy. The relationship between the structure and the mechanical properties related to elastomeric tribological properties was investigated. The properties and the mechanisms of friction and wear of bimodal elastomeric NBR networks were also analyzed. The lubricating characteristics of bimodal NBR networks were revealed based on the mechanisms of friction and wear. Results show that bimodal NBR networks are similar to bimodal polydimethylsiloxane networks. The form and density of the network structure can be controlled from elastomeric networks to thermosetting resin networks. The mechanical properties of bimodal NBR networks, such as elasticity, elongation at break, fatigue characteristic, tensile strength, elastic modulus, and thermal stability can be precisely controlled following the variation in network structure. The friction, wear, and lubrication of bimodal NBR networks can be clearly described according to the principles of tribology. Common elastomers cannot simultaneously reduce friction and wear because of the different mechanisms of friction and wear; however, bimodal elastomer networks can efficiently address this problem

  13. Description of gasket failure in a 7 cell PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Attila; Serra, Maria [Institut de Robotica i Informatica Industrial, Parc Tecnologic de Barcelona, Edifici U, C. Llorens i Artigas, 4-6, 2a Planta, 08028 Barcelona (Spain); Kunusch, Cristian [Laboratorio de Electronica Industrial Control e Instrumentacion, Facultad de Ingenieria, UNLP (Argentina)

    2007-06-10

    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell 2. This stack failure analysis revealed a series of indicators that could be used by a super visional controller in order to initiate a shutdown procedure. (author)

  14. Sierpi\\' nski Gasket Graphs and Some of Their Properties

    CERN Document Server

    Teguia, A M; Teguia, Alberto M.; Godbole, Anant P.

    2005-01-01

    The {\\it Sierpi\\'nski fractal} or {\\it Sierpi\\'nski gasket} $\\Sigma$ is a familiar object studied by specialists in dynamical systems and probability. In this paper, we consider a graph $S_n$ derived from the first $n$ iterations of the process that leads to $\\Sigma$, and study some of its properties, including its cycle structure, domination number and pebbling number. Various open questions are posed.

  15. Spectral Asymptotics for $V$-variable Sierpinski Gaskets

    OpenAIRE

    Freiberg, U.; Hambly, B.M.; Hutchinson, John E.

    2015-01-01

    The family of $V$-variable fractals provides a means of interpolating between two families of random fractals previously considered in the literature; scale irregular fractals ($V=1$) and random recursive fractals ($V=\\infty$). We consider a class of $V$-variable affine nested fractals based on the Sierpinski gasket with a general class of measures. We calculate the spectral exponent for a general measure and find the spectral dimension for these fractals. We show that the s...

  16. Elastomeric organic material for switching application

    Science.gov (United States)

    Shiju, K.; Praveen, T.; Preedep, P.

    2014-10-01

    Organic Electronic devices like OLED, Organic Solar Cells etc are promising as, cost effective alternatives to their inorganic counterparts due to various reasons. However the organic semiconductors currently available are not attractive with respect to their high cost and intricate synthesis protocols. Here we demonstrate that Natural Rubber has the potential to become a cost effective solution to this. Here an attempt has been made to fabricate iodine doped poly isoprene based switching device. In this work Poly methyl methacrylate is used as dielectric layer and Aluminium are employed as electrodes.

  17. Elastomeric organic material for switching application

    International Nuclear Information System (INIS)

    Organic Electronic devices like OLED, Organic Solar Cells etc are promising as, cost effective alternatives to their inorganic counterparts due to various reasons. However the organic semiconductors currently available are not attractive with respect to their high cost and intricate synthesis protocols. Here we demonstrate that Natural Rubber has the potential to become a cost effective solution to this. Here an attempt has been made to fabricate iodine doped poly isoprene based switching device. In this work Poly methyl methacrylate is used as dielectric layer and Aluminium are employed as electrodes

  18. Elastomeric organic material for switching application

    Energy Technology Data Exchange (ETDEWEB)

    Shiju, K., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com; Praveen, T., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com; Preedep, P., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com [Laboratory for Molecular Photonics and Electronics (LAMP), Department of Physics, National Institute of Technology, Calicut, Kerala, 673601 (India)

    2014-10-15

    Organic Electronic devices like OLED, Organic Solar Cells etc are promising as, cost effective alternatives to their inorganic counterparts due to various reasons. However the organic semiconductors currently available are not attractive with respect to their high cost and intricate synthesis protocols. Here we demonstrate that Natural Rubber has the potential to become a cost effective solution to this. Here an attempt has been made to fabricate iodine doped poly isoprene based switching device. In this work Poly methyl methacrylate is used as dielectric layer and Aluminium are employed as electrodes.

  19. Deformation characteristics and its effect on sealability of metal gaskets suffering thermal degradation

    International Nuclear Information System (INIS)

    In order to obtain the performance of the metal gaskets suffering thermal degradation used at the lid of the spent fuel dual-purpose cask, compression test and sliding test were conducted. The result of the compression tests show that the amount of the elastic recovery of the metal gasket suffering thermal degradation is smaller than that of the gasket with no degradation and the leak-tightness is kept sound even under no compressive load because of adhesion of the metal gasket surface to the flanges. It is clear from the sliding test that leak-tightness formed by metal gasket is very sensitive to the sliding phenomena of the flanges. From the observation of the section and contact surface of the metal gaskets after the tests, the increase of the leak rate seems to be mainly due to the distortion of the gasket and the change of minute cervices in the contact surface of the gasket and the change of minute crevices in the contact surface of the gasket. (author)

  20. Development of radiation resistant EPDM based rubber compound for gasket application

    International Nuclear Information System (INIS)

    The elastomer material selected for seals for applications in reprocessing plant is required to possess both radiation and chemical resistance. Ethylene propylene diene monomer (EPDM) is used for gasket application in chemical industries due to its excellent resistance to heat, oxidation, ozone and weather ageing. To ascertain the suitability of EPDM for applications in radioactive environment, EPDM rubber compound was developed and its radiation tolerance has been evaluated by exposing to gamma radiation and measuring the change in the mechanical properties. EPDM rubber, ZnO, MgO, carbon black, aromatic oil, ethylene thiourea and stearic acid were the materials used for the development of rubber compound. Mixing was done as per ASTM D-3182 practice in a laboratory two-roll mill using the mixing cycle for the required formulation. Test slabs and buttons of the mixed compounds were obtained by compression-moulding technique as per ASTM D-3192 procedure and according to the optimum cure time got from Rheometric studies. The rubber compound was sheeted out to an uniform thickness of 2 mm and the product moulding was carried out in a hydraulic compression moulding press at 155? for a curing time of 20 min. The mechanical properties of the rubber compound were determined and were exposed to gamma radiation at the dose of 105, 106, 107 and 108 rads to understand the effect of radiation on the rubber compound. The mechanical properties measured for the rubber compound were 41 MPa as tensile strength, 550% as elongation at break, 39% as compression set and 67 as shore A hardness. These properties degraded with radiation. Degradation is due to the formation of radicals by radiation and subsequent chain scission and crosslinking. Increase in hardness by 11 points was observed after exposure to 108 rads. Tensile strength decreased to 61% and elongation at break decreased to 57% after 108 rads. Compression set, which is the important property of a gasket material was found to increase from 39 to 60% since elasticity is decreased by radiation. Comparison of the mechanical properties of EPDM rubber compound before and after irradiation indicated that the gasket can be used in the plant up to the radiation level of 5 x 107 rads. (author)

  1. Statistical mechanics of the travelling salesman on the Sierpinski gasket

    OpenAIRE

    Bradley, R. M.

    1986-01-01

    We study the statistical mechanics of the travelling salesman on a Sierpinski gasket in which the bond lengths { ?i } are quenched random variables. The problem of finding the shortest closed path which visits all N sites is tractable if all the| ?i — 1 | are less than (2 N + 1)-1. For a particular choice of the bond-length probability distribution and at low temperatures, the system behaves like a set of non-interacting Ising spins in a quenched random magnetic field. The relevance of on...

  2. Description of gasket failure in a 7 cell PEMFC stack

    OpenAIRE

    Husar, Attila; Serra, Maria; Kunusch, Cristian

    2007-01-01

    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode ...

  3. Analytical and Experimental Studies of Liquid and Gas Leaks through Micro and Nano-Porous Gaskets

    Directory of Open Access Journals (Sweden)

    Lotfi Grine

    2013-08-01

    Full Text Available The reliability of industrial installation requires minimum leakage of pressurized sealed joints during operation. At the design stage, the leakage behavior of the gasket must be one of the most important parameter in the gasket selection. The objective of the work presented in this paper is to develop an analytical leak rate prediction methodology used in gasketed joints. A pseudo analytical-experimental innovative approach was used to estimate the characteristics of the porous structure for the purpose of predicting accurate leak rate through gaskets with different fluids under conditions similar to those of operation. The analytical model assumes the flow to be continuum but employs a slip boundary condition on the leak path wall to determine the porosity parameters of the gasket. The analytical model results are validated and confronted against experimental data which were conducted under various conditions of fluid media, pressure, gasket stress and temperature. Two experimental test rigs fully automate that accurately reproduces the real leakage behavior of the gasketed joint have been developed to analyze the mechanical and thermal effects on the gasket flow regime. The gas leaks were measured with multi-gas mass spectrometers while liquid leaks were measure using a sophisticated detection system based on the pressure rise method.

  4. The characteristic of blind flanged bolted joints with full-face gaskets

    International Nuclear Information System (INIS)

    In this paper, the characteristics of blind flanged bolted joints with full-face gaskets such as the contact stress distributions and the variation of axial bolt force are analyzed using axisymmetrical theory of elasticity. The effect of Young's modulus of gaskets, the gasket thickness and the bolt pitch circle diameter on the contact stress distribution are clarified by the numerical calculations. In the experiments, the contact stress distributions were measured by sensitive films when the gasket is asbestos. Variations of axial bolt force are measured using strain gages. The internal pressure is observed when the internal fluid starts to leak. The numerical results are in fairly good agreement with the experimental results. Discussions are made on the sealing performance of gaskets used in these experiments

  5. Comparative study of the behaviour of conventional gasketed and compact non-gasketed flanged pipe joints under bolt up and operating conditions

    International Nuclear Information System (INIS)

    Bolted flanged joints comprise an assembly of a number of important individual components, which are required to perform well together in service. The ideal requirement for a bolted flange joint is a 'zero-leak' condition. However, whilst recommended design procedures for bolted flange joints are available in international codes and standards, leakage problems are still faced by industry. These are common in both normal operating (internal pressure loading) and critical event conditions. The drive is, therefore, to find a flange joint assembly, which provides 'zero-leak condition' and requires little or no maintenance and handling. Considerable investigation in the area of optimised bolted joints has been in progress for the past 10 years comparing traditional gasketed joints and 'compact non-gasketed' joints, using both analytical and experimental approaches. In this present study, two-dimensional non-linear finite element studies have been performed for both gasketed and non-gasketed bolted flange pipe joints. Based on the stress results for the flange and the bolt and the flange rotation/displacement, compact non-gasketed flange joints are shown to be a viable and preferable alternative to the conventional gasketed flange joints. Recommendations are made for a best-fit flange model for static load conditions with 'zero-leak' sealing in a flange joint

  6. Modelling leaktightness in a sealing system using elastomeric seal

    International Nuclear Information System (INIS)

    The container of radioactive gases in a transport cask is governed by the efficiency of the sealing system. The gas release of an elastomeric seal can have two causes: 1) the permeation through the elastomer which is an intrinsic characteristic for the material. 2) the leakage through geometrical defects (cracks, gaps, capillaries...) which are of a random nature. The purpose of this study is to develop representative models of these two leakage processes. In order to validate these models, experimental measurements were performed with a specific equipment ('LISE' test rig), to carry out tests with O-ring in a trapezoidal groove within a temperature range from -50degC to +300degC. The leakage rate was measured with a mass spectrometer using pure gases or gas mixtures. (J.P.N.)

  7. Elastomeric carbon nanotube circuits for local strain sensing

    CERN Document Server

    Maune, H

    2006-01-01

    We use elastomeric polydimethylsiloxane substrates to strain single-walled carbon nanotubes and modulate their electronic properties, with the aim of developing flexible materials that can sense local strain. We demonstrate micron-scale nanotube devices that can be cycled repeatedly through strains as high as 20% while providing reproducible local strain transduction by via the device resistance. We also compress individual nanotubes, and find they undergo an undulatory distortion with a characteristic spatial period of 100-200 nm. The observed period can be understood by the mechanical properties of nanotubes and the substrate in conjunction with continuum elasticity theory. These could potentially be used to create superlattices within individual nanotubes, enabling novel devices and applications.

  8. A Comparative Study on the Efficiency of Pigmented and non Pigmented Elastomeric Chains Using Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Joby Paulose

    2010-12-01

    Full Text Available Orthodontic treatment involves the use of force delivery systems such as arch wires and elastomeric chains. Their mechanical property varies among various manufacturers. It depends on their phase transformation temperature. Differential scanning calorimetry (DSC is a method of thermal analysis which is extensively employed to assess the properties of orthodontic materials. In the field of orthodontics DSC is used to assess the phase transition temperature of orthodontic arch wires, glass transition temperature of polyurethane elastomers, and to evaluate the degree of cure of dental resins. The present study highlights the clinical application of differential scanning calorimetry in evaluating the Glass transition temperature of polyurethane elastomeric chains.

  9. In-situ permeation tests of elastomeric O-ring seals

    International Nuclear Information System (INIS)

    A series of in-situ permeation tests are being conducted to determine permeation coefficients and breakthrough and saturation times for certain elastomeric O-rings with various gases that might be used as leak test tracers. The work is directed towards developing more effective and efficient nuclear material shipping packaging leak test procedures. The tests are in progress presently, and a formal report will be published in 1984

  10. Penetration of a glass-faced transparent elastomeric resin by a lead-antimony-cored bullet

    OpenAIRE

    Hazell, P. J.; Edwards, M. R.; Longstaff, H.; Erskine, J.

    2008-01-01

    The penetration of the lead antimony-cored 7.62 mm × 51 mm bullet into a glass- faced polyurethane elastomeric polymer resin has been studied. The resulting craters in the resin contained elongated bullet core material that had a significant amount of porosity. A simple linear viscoelastic model was applied to AUTODYN-2D to describe the behaviour of the resin and numerical results of the penetration mechanism and depth-of-penetration appeared to match experimental observati...

  11. Random walks on Sierpinski gaskets of different dimensions.

    Science.gov (United States)

    Weber, Sebastian; Klafter, Joseph; Blumen, Alexander

    2010-11-01

    We study random walks (RWs) on classical and dual Sierpinski gaskets (SG and DSG), naturally embedded in d-dimensional Euclidian spaces (ESs). For large d the spectral dimension d(s) approaches 2, the marginal RW dimension. In contrast to RW over two-dimensional ES, RWs over SG and DSG show a very rich behavior. First, the time discrete scale invariance leads to logarithmic-periodic (log-periodic) oscillations in the RW properties monitored, which increase in amplitude with d. Second, the asymptotic approach to the theoretically predicted RW power laws is significantly altered depending on d and on the variant of the fractal (SG or DSG) under study. In addition, we discuss the suitability of standard RW properties to determine d(s), a question of great practical relevance. PMID:21230459

  12. A Digital Image Steganography using Sierpinski Gasket Fractal and PLSB

    Science.gov (United States)

    Rupa, Ch.

    2013-09-01

    Information attacks are caused due to the weaknesses in the information security. These attacks affect the non-repudiation and integrity of the security services. In this paper, a novel security approach that can defend the message from information attacks is proposed. In this new approach the original message is encrypted by Fractal Sierpinski Gasket (FSG) cryptographic algorithm, that result is hidden into an image using penultimate and least significant bit (PLSB) embedding method. This method makes the security more robust than conventional approach. Important properties of fractals are sensitivity and self similarity. These can be exploited to produce avalanche effect. Stegoanalysis of the proposed method shows that it is resistant to various attacks and stronger than the existed steganographic approaches.

  13. Random walks on Sierpinski gaskets of different dimensions

    Science.gov (United States)

    Weber, Sebastian; Klafter, Joseph; Blumen, Alexander

    2010-11-01

    We study random walks (RWs) on classical and dual Sierpinski gaskets (SG and DSG), naturally embedded in d -dimensional Euclidian spaces (ESs). For large d the spectral dimension ds approaches 2, the marginal RW dimension. In contrast to RW over two-dimensional ES, RWs over SG and DSG show a very rich behavior. First, the time discrete scale invariance leads to logarithmic-periodic (log-periodic) oscillations in the RW properties monitored, which increase in amplitude with d . Second, the asymptotic approach to the theoretically predicted RW power laws is significantly altered depending on d and on the variant of the fractal (SG or DSG) under study. In addition, we discuss the suitability of standard RW properties to determine ds , a question of great practical relevance.

  14. Surface effects on in-plane buckling of nanowires on elastomeric substrates

    International Nuclear Information System (INIS)

    Buckling of nanowires on elastomeric substrates shows enhanced stretchability for these materials, and can foster stretchable form of nanoelectronics and nanosystems. Since surface effects can have strong influence on the mechanical behaviour of nanowires, a theoretical model is established to study the surface effects on in-plane buckling of nanowires on elastomeric substrates. The buckling wavelength, amplitude and critical buckling strain are obtained analytically in terms of surface elasticity, residual surface tension, bending and tension stiffness of the nanowire and the elastic modulus of the substrate. The results show that the buckling wavelength is only dependent on the surface elasticity, while both surface elasticity and residual surface tension can have significant effects on the buckling amplitude and critical buckling strain. (paper)

  15. Hybrid magnetorheological fluid–elastomeric lag dampers for helicopter stability augmentation

    International Nuclear Information System (INIS)

    A laboratory demonstration of a hybrid magnetorheological fluid–elastomeric (MRFE) damper is investigated for adjustable or programmable lag mode damping in helicopters, so that damping requirements can be varied as a function of different flight conditions. The laboratory demonstration of this hybrid MRFE lag damper consists of a double lap shear elastomeric damper in parallel with two magnetorheological (MR) flow mode dampers. This is compared to a damper where only elastomeric materials are implemented, i.e., a double lap shear specimen. The relationship between the output force and the quasi-steady harmonic displacement input to a flow mode MR damper is exploited, where the output force can be adjusted as a function of applied magnetic field. Equivalent viscous damping is used to compare the damping characteristics of the hybrid damper to a conventional elastomeric damper under steady-state sinusoidal displacement excitation. To demonstrate feasibility, a hybrid MRFE damper test setup is designed, and single frequency (lag frequency or rotor in-plane bending frequency) and dual frequency (lag frequency and rotor frequency) tests are conducted under different magnetic fields. The hybrid MRFE damper exhibits amplitude-dependent damping behavior. However, with application of a magnetic field, the damping level is controlled to a specific damping level objective as a function of displacement amplitude. Similarly, under dual frequency conditions, damping degradation equency conditions, damping degradation at the lag frequency, because of lag motion at the rotor frequency, can also be recovered by increasing magnetic field. A time-domain analysis is developed to study the nonlinear dynamic behavior of the hybrid MRFE damper. Using rate-dependent elasto-slides, the amplitude-dependent behavior of the hybrid MRFE damper is accurately reconstructed using both constant and current-dependent (i.e. controllable) parameters. The analysis is physically motivated and can be applied to the elastomer and MR fluid damper components separately

  16. Metric characterization of cluster dynamics on the Sierpinski gasket

    International Nuclear Information System (INIS)

    We develop and implement an algorithm for the quantitative characterization of cluster dynamics occurring for cellular automata defined on an arbitrary structure. As a prototype for such systems we focus on the Ising model on a finite Sierpinski gasket, which is known to possess a complex thermodynamic behavior. Our algorithm requires the projection of evolving configurations into an appropriate partition space, where an information-based metric (the Rohlin distance) can be naturally defined and worked out in order to detect the changing and the stable components of clusters. The analysis highlights the existence of different temperature regimes according to the size and the rate of change of clusters. Such regimes are, in turn, related to the correlation length and the emerging 'critical' fluctuations, in agreement with previous thermodynamic analysis, hence providing a non-trivial geometric description of the peculiar critical-like behavior exhibited by the system. Moreover, at high temperatures, we highlight the existence of different timescales controlling the evolution towards chaos

  17. Elastomeric composites based on carbon nanomaterials

    Science.gov (United States)

    Araby, Sherif; Meng, Qingshi; Zhang, Liqun; Zaman, Izzuddin; Majewski, Peter; Ma, Jun

    2015-03-01

    Carbon nanomaterials including carbon black (CB), carbon nanotubes (CNTs) and graphene have attracted increasingly more interest in academia due to their fascinating properties. These nanomaterials can significantly improve the mechanical, electrical, thermal, barrier, and flame retardant properties of elastomers. The improvements are dependent on the molecular nature of the matrix, the intrinsic property, geometry and dispersion of the fillers, and the interface between the matrix and the fillers. In this article, we briefly described the fabrication processes of elastomer composites, illuminated the importance of keeping fillers at nanoscale in matrices, and critically reviewed the recent development of the elastomeric composites by incorporating CB, CNTs, and graphene and its derivatives. Attention has been paid to the mechanical properties and electrical and thermal conductivity. Challenges and further research are discussed at the end of the article.

  18. Friction of soft elastomeric wrinkled surfaces

    Science.gov (United States)

    Rand, Charles J.; Crosby, Alfred J.

    2009-09-01

    We evaluate the sliding of a rigid spherical lens over a surface-wrinkled, elastomeric substrate. Sliding is conducted both parallel and perpendicular to the aligned surface wrinkles, and the sliding force is compared to the required sliding forces on nonwrinkled surfaces. We evaluate the effects of wrinkle dimensions and applied normal force on the sliding resistance. A simple Bowden-Tabor friction model can describe the dependence of the sliding force on normal load, with different coefficients of friction associated with the nonwrinkled and wrinkled surfaces both perpendicular and parallel. The aspect ratio of the wrinkles has a secondary effect on the sliding force. We associate the changes in friction to changes in the tangential stiffness and fracture angle caused by the surface wrinkles.

  19. Device to measure temperature of an annular elastomeric seal

    International Nuclear Information System (INIS)

    A device for measuring in situ the temperature of an annular elastomeric seal is provided which comprises, in a preferred embodiment thereof, an annular elastomeric seal formed of two annular halves, a thermocouple embedded in said seal near the interface of said annular halves, a sleeve having one end molded to one of said halves for supporting and protecting the thermocouple leads and for conducting said leads external of the housing or fixture incorporating said seal

  20. Solvent-resistant elastomeric microfluidic devices and applications

    Science.gov (United States)

    van Dam, Robert Michael

    Microfluidics is increasingly being used in many areas of biotechnology and chemistry to achieve reduced reagent volumes, improved performance, integration, and parallelism, among other advantages. Though early devices were based on rigid materials such as glass and silicon, elastomeric materials such as polydiznethylsiloxane (PDMS) are rapidly emerging as a ubiquitous platform for applications in biotechnology. This is due, in part, to simpler fabrication procedures and to the ability to integrate mechanical microvalves at vastly greater densities. For many applications in the areas of chemical synthesis and analysis, however, PDMS cannot replace glass and silicon due to its incompatibility with many solvents and reagents. Such areas could benefit tremendously from the development of an elastomeric microfluidic device technology that combines the advantages of PDMS with the property of solvent resistance. Simplified fabrication could increase the accessibility of microfluidics, and the possibility of dense valve integration could lead to significant advances in device sophistication. Applications could be more rapidly developed by design re-use due to the independence of mechanical valves on fluid properties (unlike electrokinetic pumping), and the property of permeability could enable novel fluidic functions for accessing a broader range of reactions than is possible in glass and silicon. The first half of this thesis describes our strategies and efforts to develop this new enabling technology. Several approaches are presented in Chapter 3, and two particularly successful ones, based on new elastomers (FNB and PFPE), are described in Chapters 4 and 5. Chapter 6 describes a novel method of fabricating devices from 3D molds that could expand the range of useful clastomers. The second half of this thesis discusses microfluidic combinatorial synthesis and high throughput screening-applications that take particular advantage of the ability to integrate thousands of individual valves and reaction chambers. Chapter 7 introduces several scalable device architectures and presents results of preliminary steps toward the synthesis of combinatorial DNA and peptide arrays. A novel method of performing universal gene expression analysis with combinatorial DNA arrays is described in Chapter 8 and an algorithm for predicting relationships among genes from gene expression array data is presented in Chapter 9.

  1. Diseño de un proceso de separación de los componentes de residuos metaloplásticos de la fabricación de juntas para estanqueidad en la empresa FRACO S. A. / Designing a Process for Separating Leftover Metoplastic Materials in the Production of Engine Gaskets at FRACO S.A. / Desenho de um processo de separação dos componentes de resíduos metaloplásticos da fabricação de juntas de estanqueidade na empresa FRACO S. A.

    Scientific Electronic Library Online (English)

    Óscar Buitrago, Suescún; Víctor, Zambrano Gómez; Daniel, Zambrano Arroyo.

    2008-12-01

    Full Text Available O presente artigo apresenta os resultados da primeira etapa do Projeto de recuperação contingente no marco de cooperação universidade-empresaestado, financiado por Colciencias e executado pela Universidade de Boyaca e a Fabrica Colombiana de Peças Automotoras (FRACO S. A.), que consiste em buscar al [...] ternativas de reaproveitamento para os materiais metaloplásticos, sobra do processo de elaboração de juntas de estanqueidade para motor. Nesta fase da pesquisa foi estudada a forma de separar os materiais que conformam esses materiais para duas referências do produto denominados FracoPlay e FracoPack. O estudo recorreu um árduo trabalho de laboratório, guiado por um estrito desenho estadístico, no qual foram provados dois agentes de separação em diferentes condições de concentração e temperatura. Os resultados obtidos são exitosos e permitem iniciar a etapa de elaboração de novos materiais a partir dos separados. Abstract in spanish El presente artículo presenta los resultados de la primera etapa del Proyecto de recuperación contingente en el marco de cooperación universidad-empresa-Estado, financiado por Colciencias y ejecutado por la Universidad de Boyacá y la Fábrica Colombiana de Repuestos Automotores (FRACO S. A.), que con [...] siste en buscar alternativas de reaprovechamiento para los materiales metaloplásticos sobrantes del proceso de elaboración de juntas de estanqueidad para motor. En esta fase de la investigación se estudió la forma de separar los materiales que conforman estos materiales para dos referencias de producto denominados FracoPlay y FracoPack. Se recurrió a un arduo trabajo de laboratorio, guiado por un estricto diseño estadístico, en el que se probaron dos agentes de separación a diferentes condiciones de concentración y temperatura. Los resultados obtenidos son exitosos y permiten iniciar la etapa de elaboración de nuevos materiales a partir de los separados. Abstract in english This article shows the results of the first stage of the project Contingent Recovery under a University-Company-State Cooperation framework, sponsored by Colciencias and carried out by the University of Boyacá and the Colombian Factory for Auto Parts (FRACO S.A). This project seeks alternatives for [...] re-usage of leftover metoplastic materials from the process of producing gaskets for engines. This phase of research deals with the manner of separating the components that form these materials, with reference to two of the products called FracoPlay and FracoPack. Extensive lab work was involved, guided by a well-planned statistical design in which the separation agents were tested at different conditions of concentration and temperature. The results obtained are satisfactory and allow the beginning of the development stage of new materials from the separated ones.

  2. Development of a snubber type magnetorheological fluid elastomeric lag damper for helicopter stability augmentation

    Science.gov (United States)

    Ngatu, Grum T.

    Most advanced helicopter rotors are typically fitted with lag dampers, such as elastomeric or hybrid fluid-elastomeric (FE) lag dampers, which have lower parts counts, are lighter in weight, easier to maintain, and more reliable than conventional hydraulic dampers. However, the damping and stiffness properties of elastomeric and fluid elastomeric lag dampers are non-linear functions of lag/rev frequency, dynamic lag amplitude, and operating temperature. It has been shown that elastomeric damping and stiffness levels diminish markedly as amplitude of damper motion increases. Further, passive dampers tend to present severe damping losses as damper operating temperature increases either due to in-service self-heating or hot atmospheric conditions. Magnetorheological (MR) dampers have also been considered for application to helicopter rotor lag dampers to mitigate amplitude and frequency dependent damping behaviors. MR dampers present a controllable damping with little or no stiffness. Conventional MR dampers are similar in configuration to linear stroke hydraulic type dampers, which are heavier, occupy a larger space envelope, and are unidirectional. Hydraulic type dampers require dynamic seal to prevent leakage, and consequently, frequent inspections and maintenance are necessary to ensure the reliability of these dampers. Thus, to evaluate the potential of combining the simplicity and reliability of FE and smart MR technologies in augmenting helicopter lag mode stability, an adaptive magnetorheological fluid-elastomeric (MRFE) lag damper is developed in this thesis as a retrofit to an actual fluid-elastomeric (FE) lag damper. Consistent with the loading condition of a helicopter rotor system, single frequency (lag/rev) and dual frequency (lag/rev at 1/rev) sinusoidal loading were applied to the MRFE damper at varying temperature conditions. The complex modulus method was employed to linearly characterize and compare the performance of the MRFE damper with the baseline FE damper performance. Based on experimental measurements, it is shown in the research that at all test temperatures, a significant damping control range, extending beyond the baseline FE damper, can be provided by the MRFE damper with the application of varying magnetic fields. This controllable damping range can be programmed to potentially provide the required damping augmentation as a function of different flight conditions. The added benefits of employing smart MR fluids in MRFE lag dampers are to produce adequate damping at critical flight conditions while concurrently reducing periodic hub loads at other flight conditions and to compensate damping losses associated with temperature. The other main objective of the present research is to develop and formulate a comprehensive analytical model that can accurately describe the non-linear hysteretic behavior that is demonstrated by the MRFE lag damper. Thus, a hydromechanical model, which can delineate the physical flow motion of the system and accurately describe the non-linear hysteretic behavior of the MRFE damper is proposed. The hydromechanical model explored in this study is a design-based model which describes the damper system with a series of lumped hydraulic, mechanical and magnetorheological components. The model employs physical parameters such as inertia, damping, yield force and compliances that are dependent on damper geometry and material properties of components and which can potentially be approximated a priori. Further, temperature variation will mainly cause material properties to change. Once model parameters have been established, the model is shown to simulate accurately the measured hysteretic force-displacement history under single and dual frequency excitations, and varying temperatures.

  3. Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

    International Nuclear Information System (INIS)

    Longterm physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 108--109 Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications

  4. Mechanical-property changes of structural composite materials after low-temperature proton irradiation: Implications for use in SSC magnet systems

    International Nuclear Information System (INIS)

    Long-term physical, mechanical, electrical, and other properties of advanced composites, plastics, and other polymer materials are greatly affected by high-energy proton, neutron, electron, and gamma radiation. The effects of high-energy particles on materials is a critical design parameter to consider when choosing polymeric structural, nonstructural, and elastomeric matrix resin systems. Polymer materials used for filled resins, laminates, seals, gaskets, coatings, insulation and other nonmetallic components must be chosen carefully, and reference data viewed with caution. Most reference data collected in the high-energy physics community to date reflects material property degradation using other than proton irradiations. In most instances, the data were collected for room-temperature irradiations, not 4.2 K or other cryogenic temperatures, and at doses less than 108-109 Rad. Energetic proton (and the accompanying spallation-product particles) provide good simulation fidelity to the expected radiation fields predicted for the cold-mass regions of the SSC magnets, especially the corrector magnets. The authors present here results for some structural composite materials which were part of a larger irradiation-characterization of polymeric materials for SSC applications

  5. Effect of storage period on the accuracy of elastomeric impressions

    Scientific Electronic Library Online (English)

    Eduardo Batista, Franco; Leonardo Fernandes da, Cunha; Ana Raquel, Benetti.

    2007-06-01

    Full Text Available AIMS: To investigate the effect of the storage period on the accuracy of recently developed elastomeric materials. METHODS: Simultaneous impressions of a steel die were taken using a polyether (I: Impregum Soft Heavy and Light body, 3M ESPE) and vinyl polysiloxane (P: Perfectim Blue Velvet and Flexi [...] -Velvet, J.Morita). The trays were loaded with the heavy-bodied impression materials while the light-bodied impression materials were simultaneously spread on the steel die. The impressions were poured after 2 hours, 24 hours, and 7 days. Impressions were stored at approximately 55% relative humidity and room temperature. Ten replicas were produced for each experimental condition (n=60). Accuracy of the stone dies was assessed with a depth-measuring microscope. The difference in height between the surface of the stone die and a standard metallic ring was recorded in micrometers at four demarcated points, by two independent examiners. Data were submitted to two-way ANOVA and Tukey test (a = 0.05). RESULTS: Significant differences were found among the groups. Smaller discrepancies were observed when pouring was performed up to 24 hours (I-2h= 65.0 ± 15.68 µm; I-24h= 81.6 ± 11.13 µm) for the polyether, and up to 7 days for the vinyl polysiloxane (P-2h= 79.1 ± 13.82 µm; P-24h= 96.8 ± 6.02 µm; P-7d= 81.4 ± 4.3 µm). Significant dimensional discrepancies, however, were observed when polyether was stored for 7 days (I-7d= 295.3 ± 17.4 µm). CONCLUSION: Storage may significantly affect the dimensional accuracy of impressions and, thus, a maximum period and storage condition should be specified for the recently developed materials.

  6. Synthesis and Characterization of Elastomeric Heptablock Terpolymers Structured by Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Alfonzo, C.Guillermo; Fleury, Guillaume; Chaffin, Kimberly A.; Bates, Frank S. (UMM); (Medtronic)

    2010-12-07

    We report the synthesis and characterization of fully saturated hydrocarbon block copolymer thermoplastic elastomers with competitive mechanical properties and attractive processing features. Block copolymers containing glassy poly(cyclohexylethylene) (C), elastomeric poly(ethylene-alt-propylene) (P), and semicrystalline poly(ethylene) (E) were produced in a CEC-P-CEC heptablock architecture, denoted XPX, by anionic polymerization and catalytic hydrogenation. The X blocks contain equal volume fractions of C and E, totaling 40%-60% of the material overall. All the XPX polymers are disordered above the melt temperature for E (T{sub m,E} {approx_equal} 95 C) as evidenced by SAXS and dynamic mechanical spectroscopy measurements. Cooling below T{sub m,E} results in crystallization of the E blocks, which induces microphase segregation of E, C, and P into a complex morphology with a continuous rubbery domain and randomly arranged hard domains as shown by TEM. This mechanism of segregation decouples the processing temperature from the XPX molecular weight up to a limiting value. Tensile mechanical testing (simple extension and cyclic loading) demonstrates that the tensile strength (ca. 30 MPa) and strain at break (>500%) are comparable to the behavior of CPC triblock thermoplastic elastomers of similar molecular weight and glass content. However, in the CPC materials, processability is constrained by the order-disorder transition temperature, limiting the applications of these materials. Elastic recovery of the XPX materials following seven cycles of tensile deformation is correlated with the fraction of X in the heptablock copolymer, and the residual strain approaches that of CPC when the fraction of hard blocks f{sub X} {le} 0.39.

  7. Effect of storage period on the accuracy of elastomeric impressions

    Directory of Open Access Journals (Sweden)

    Eduardo Batista Franco

    2007-06-01

    Full Text Available AIMS: To investigate the effect of the storage period on the accuracy of recently developed elastomeric materials. METHODS: Simultaneous impressions of a steel die were taken using a polyether (I: Impregum Soft Heavy and Light body, 3M ESPE and vinyl polysiloxane (P: Perfectim Blue Velvet and Flexi-Velvet, J.Morita. The trays were loaded with the heavy-bodied impression materials while the light-bodied impression materials were simultaneously spread on the steel die. The impressions were poured after 2 hours, 24 hours, and 7 days. Impressions were stored at approximately 55% relative humidity and room temperature. Ten replicas were produced for each experimental condition (n=60. Accuracy of the stone dies was assessed with a depth-measuring microscope. The difference in height between the surface of the stone die and a standard metallic ring was recorded in micrometers at four demarcated points, by two independent examiners. Data were submitted to two-way ANOVA and Tukey test (a = 0.05. RESULTS: Significant differences were found among the groups. Smaller discrepancies were observed when pouring was performed up to 24 hours (I-2h= 65.0 ± 15.68 µm; I-24h= 81.6 ± 11.13 µm for the polyether, and up to 7 days for the vinyl polysiloxane (P-2h= 79.1 ± 13.82 µm; P-24h= 96.8 ± 6.02 µm; P-7d= 81.4 ± 4.3 µm. Significant dimensional discrepancies, however, were observed when polyether was stored for 7 days (I-7d= 295.3 ± 17.4 µm. CONCLUSION: Storage may significantly affect the dimensional accuracy of impressions and, thus, a maximum period and storage condition should be specified for the recently developed materials.

  8. Influence of elastomeric seal plate surface chemistry on interface integrity in biofouling-prone systems: Evaluation of a hydrophobic "easy-release" silicone-epoxy coating for maintaining water seal integrity of a sliding neoprene/steel interface

    Science.gov (United States)

    Andolina, Vincent L.

    The scientific hypothesis of this work is that modulation of the properties of hard materials to exhibit abrasion-reducing and low-energy surfaces will extend the functional lifetimes of elastomeric seals pressed against them in abrasive underwater systems. The initial motivation of this work was to correct a problem noted in the leaking of seals at major hydropower generating facilities subject to fouling by abrasive zebra mussel shells and extensive corrosion. Similar biofouling-influenced problems can develop at seals in medical devices and appliances from regulators in anesthetic machines and SCUBA diving oxygen supply units to autoclave door seals, injection syringe gaskets, medical pumps, drug delivery components, and feeding devices, as well as in food handling equipment like pasteurizers and transfer lines. Maritime and many other heavy industrial seal interfaces could also benefit from this coating system. Little prior work has been done to elucidate the relationship of seal plate surface properties to the friction and wear of elastomeric seals during sliding contacts of these articulating materials, or to examine the secondary influence of mineralized debris within the contacting interfaces. This investigation utilized the seal materials relevant to the hydropower application---neoprene elastomer against carbon steel---with and without the application of a silicone-epoxy coating (WearlonRTM 2020.98) selected for its wear-resistance, hydrophobicity, and "easy-release" capabilities against biological fouling debris present in actual field use. Analytical techniques applied to these materials before and after wear-producing processes included comprehensive Contact Angle measurements for Critical Surface Tension (CA-CST) determination, Scanning Electron Microscopic inspections, together with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and X-Ray Fluorescence (XRF) measurements for determination of surface texture and inorganic composition, Multiple Attenuated Internal Reflection (MAIR-IR) and Microscopic Infrared Spectroscopy for organic surface compositional details, light microscopy for wear area quantification, and profilometry for surface roughness estimation and wear depth quantification. Pin-on-disc dynamic Coefficient of Friction (CoF) measurements provided data relevant to forecasts of seal integrity in dry, wet and biofouling-influenced sliding contact. Actual wear of neoprene seal material against uncoated and coated steel surfaces, wet and dry, was monitored after both rotary and linear cyclic wear testing, demonstrating significant reductions in elastomer wear areas and depths (and resultant volumes) when the coating was present. Coating the steel eliminated a 270% increase in neoprene surface area wear and an 11-fold increase in seal abrasive volume loss associated with underwater rusting in rotary experiments. Linear testing results confirm coating efficacy by reducing wear area in both loading regimes by about half. No coating delamination was observed, apparently due to a differential distribution of silicone and epoxy ingredients at the air-exposed vs. steel-bonded interfaces demonstrated by IR and EDS methods. Frictional testing revealed higher Coefficients of Friction (CoF) associated with the low-speed sliding of Neoprene over coated rather than uncoated steel surfaces in a wet environment, indicating better potential seal adhesion between the hydrophobic elastomer and coating than between the elastomer and intrinsically hydrophilic uncoated steel. When zebra mussel biofouling debris was present in the articulating joints, CoF was reduced as a result of a water channel path produced between the articulating surfaces by the retained biological matter. Easier release of the biofouling from the low-CST coated surfaces restored the seal integrity more rapidly with further water rinsing. Rapid sliding diminished these biofouling-related differences, but revealed a significant advantage in reducing the CoF of the elastomer-on-coating couples to less than 50% of the elastomer-on-steel coupl

  9. Magnetic resonance imaging evaluation of remodeling by cardiac elastomeric tissue scaffold biomaterials in a rat model of myocardial infarction.

    OpenAIRE

    Stuckey, Dj; Ishii, H.; Chen, Qz; Boccaccini, Ar; Hansen, U.; Carr, Ca; Roether, Ja; Jawad, H.; Tyler, Dj; Ali, Nn; Clarke, K.; Harding, SE

    2010-01-01

    Grafting of elastomeric biomaterial scaffolds may offer a radical strategy for the prevention of heart failure after myocardial infarction by increasing efficacy of stem cell delivery as well as acting as mechanical restraint devices to constrain scar expansion. Biomaterials can be partially optimized in vitro, but their in vivo performance is most critical and should ideally be monitored serially and noninvasively. We used magnetic resonance imaging (MRI) to assess three scaffold materials w...

  10. A Comparative Study on the Efficiency of Pigmented and non Pigmented Elastomeric Chains Using Differential Scanning Calorimetry

    OpenAIRE

    Joby Paulose; Rhea Mini Jayan

    2010-01-01

    Orthodontic treatment involves the use of force delivery systems such as arch wires and elastomeric chains. Their mechanical property varies among various manufacturers. It depends on their phase transformation temperature. Differential scanning calorimetry (DSC) is a method of thermal analysis which is extensively employed to assess the properties of orthodontic materials. In the field of orthodontics DSC is used to assess the phase transition temperature of orthodontic arch wires, glass tra...

  11. A 3D regression surface for the room temperature tightness gasket data reduction and bolt load design

    International Nuclear Information System (INIS)

    The purpose of the present work is to propose a new approach for modelling the tightness behaviour of the gaskets used in bolted flange joints. This new approach consists of developing a mathematical model for a three-dimensional (3D) representation of the gasket tightness performance. Rather than considering a 2D graph for characterizing the complete gasket behaviour, a third axis is added to the Sg vs. Tp plot to dissociate the unloading cycles from initial gasket tightening. This leads to the definition of a surface that is represented by a simple polynomial equation that contains six coefficients that are determined by a simple regression calculation. In the first part of the paper, the new approach is tested through a database of 406 room temperature tightness (ROTT) tests performed on different gasket styles. Then, a statistical analysis of the predictions made with the new model demonstrates its ability to predict gasket leak rates much more accurately than it was previously possible with the gasket constants derived from the ROTT Draft 9 or 10 methods. It is also demonstrated that the new approach can be used to model successfully complex gasket behaviours such as the tightness hardening phenomenon. Secondly, the effect of gas pressure change on the leak rate is analysed. It turns out that at high gasket stresses, the actual scheme of the ROTT tests may not allow enough time for reaching a stabilized leak rate value because of a transitory time effete value because of a transitory time effect in the porous structure of gaskets. Then, in order to evaluate the characteristic waiting period (dwell time) before a stabilized flow rate is achieved following a change in the gas pressure level, a simple phenomenological analysis of the flow is performed

  12. New elastomeric silicone based networks applicable as electroactive systems

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Boll, Mads

    2011-01-01

    Commercial elastomer materials are available for dielectric electroactive polymer (DEAP) purposes but the applied commercial elastomers have not been developed with the specific application in mind. It is therefore obvious that optimization of the elastomer material should be possible. In this study we focus on optimization of the mechanical properties of the elastomer and show that it is possible to lower the elastic modulus and still not compromise the other required mechanical properties such as fast response, stability, low degree of viscous dissipation and high extensibility. The elastomers are prepared from a vinyl-terminated polydimethyl siloxane (PDMS) and a 4-functional crosslinker by a platinum-catalyzed hydrosilylation reaction between the two reactants. Traditionally, elastomers based on hydrosilylation are prepared via a ‘one-step two-pot’ procedure (with a mix A and a mix B mixed in a given ratio). An alternative network formulation method is adopted in this study in order to obtain an elastomeric system with controlled topology – a so-called bimodal network. Bimodal networks are synthesized using a ‘two-step four-pot’ mixing procedure which results in a nonhomogeneous network structure which is shown to lead to novel mechanical properties due to the low extensibility of the short chains and the high extensibility of the long chains. The first ensures stability and the last retards the rupture process thereby combining two desired properties for DEAP purposes without necessarily compromising the viscous dissipation. Several elastomers are prepared and tested for the linear viscoelastic behaviour, i.e. behaviour in the small-strain limit (up to approximately 10% strain). The bimodal networks are, however, capable of extensions up to several times their initial length but the focus here is the small-strain limit.

  13. EFFICIENCY OF VIBRATION-DAMPING GASKETS WITH DRY FRICTION FOR REDUCTION NOISE OF CIRCULAR WOODWORKING MACHINES ????????????? ????????????????? ????????? ? ????? ??????? ??? ???????? ???? ?? ????????????? ???????????????????? ???????

    Directory of Open Access Journals (Sweden)

    Osmolovsky D. S.

    2011-06-01

    Full Text Available Reasonable new design for reduction noise for saw disks of woodworking machines, in which gaskets with the dry friction, placed under clamping flange are used, is shown. Experimentally received results, characterizing dissipative and acoustic properties of this design

  14. Water and steam tightness tests of expanded graphite static gaskets for nuclear power plant steam generators

    International Nuclear Information System (INIS)

    We first recalled the information which can be acquired regarding the mechanical behaviour and the tightness of spiral wound gaskets (with asbestos and with expanded graphite) and gaskets made of pure expanded graphite. Tests have been carried out under an hydraulic press at ambient temperature and up to 350 deg C, using helium (up to 200 bar) and a mass spectrometer. We briefly explained why the results achieved are not sufficient to evaluate the gasket leak rate when a liquid is used. Other tests are consequently necessary. We give a short description of the plant used to carry out tests with steam and water up to 350 deg C and 200 bar and to measure a leak rate which may vary from 10-8 g/s to 10-3 g/s and more. The procedure selected will first be indicated as well as the results obtained when using and expanded graphite gasket (ring inserted between two stainless steal rings) at various temperatures under a pressure (steam and then, water) ranging from 1 to 200 bar. (authors). 17 figs., 14 refs

  15. The assessment of service lifetimes of elastomeric seals in a nuclear environment

    International Nuclear Information System (INIS)

    Elastomeric seals are quite widely used in nuclear environments where they are exposed to low dose rate irradiation at moderate temperatures. These materials may be required to operate satisfactorily for long periods, up to the service life of the plant, therefore, their long-term behaviour under such conditions need to be assessed. Because of the timescales involved, it is usually necessary to undertake accelerated testing of the seal materials to obtain data, but many elastomers are known to exhibit dose rate effects and synergism between temperature and radiation. For this reason, data obtained in high dose rate accelerated tests need care in interpretation. A considerable amount of experimental data has previously been obtained on the behaviour of a specific elastomer under conditions of elevated temperature and high dose rate. The data from these accelerated tests have been used to develop a predictive model for assessing the behaviour of elastomeric seals under service conditions. The work reported here is an experimental validation of the predictions of the model under irradiation conditions well outside the temperature and dose rate range used to determine the model parameters. In addition the effect of the presence of water vapour during irradiation has been examined

  16. Stability of colistimethate sodium in a disposable elastomeric infusion device.

    Science.gov (United States)

    Abdulla, Alan; van Leeuwen, Roelof W F; de Vries Schultink, Aurelia H M; Koch, Birgit C P

    2015-05-30

    Infections of the respiratory tract with Pseudomonas aeruginosa in cystic fibrosis patients are frequently treated with colistimethate sodium (CMS). For the intravenous administration of CMS a disposable elastomeric pump is a convenient option. To date, there are no data available on the chemical stability of CMS solutions stored in elastomeric pumps. We evaluated the chemical stability of 0.8mg/mL solutions of CMS by measuring the degradation over a period of 7 days. Test samples were prepared by diluting CMS with saline solution (0.9%). The preparations were transferred to 100-mL elastomeric pumps and stored at 4°C. The chemical stability was measured by a high-performance liquid chromatography method with UV detection. There was no degradation of CMS (<0.5% of CMS present as colistin) for at least 3 day at 4°C, and after 7 days all test samples remained chemically stable (<5% of CMS present as colistin). Since colistin formed in pharmacy-compounded CMS solutions prior to administration may cause toxicity, we advise that the solution should be used before the hydrolysis of CMS occurs. Therefore, we recommend that the 0.8mg/mL solution of CMS can be stored for up to 3 days at 4°C in an elastomeric pump. PMID:25863116

  17. AVALIAÇÃO DA CAPACIDADE DE CÓPIA DE MATERIAIS DE MOLDAGEM ELASTOMÉRICOS DE DIFERENTES SISTEMAS POR MEIO DE UMA TÉCNICA APLICÁVEL CLINICAMENTE / EVALUATION OF THE COPYING ABILITY OF DIFFERENT ELASTOMERIC IMPRESSION MATERIALS USING A CLINICALLY APPLICABLE TECHNIQUE

    Scientific Electronic Library Online (English)

    Rossana Pereira de Almeida, ANTUNES; Wilson, MATSUMOTO; Heitor, PANZERI.

    1997-10-01

    Full Text Available O objetivo deste trabalho foi realizar um estudo comparativo entre diferentes sistemas de materiais de moldagem, tais como o polissulfeto, a silicona de condensação e a silicona de adição, através de uma nova técnica de avaliação não destrutiva e, conseqüentemente, aplicável clinicamente. A partir d [...] a confecção de próteses fixas de três elementos, fundidas em liga de níquel-cromo, obtiveram-se réplicas tridimensionais do espaço entre a restauração e o preparo cavitário, utilizando-se uma silicona de condensação. Essas réplicas foram avaliadas microscopicamente. Os resultados indicaram que, embora alguns materiais tenham apresentado comportamento superior, como o Permlastic e o Extrude, os outros materiais estudados tiveram comportamento clinicamente aceitável, desde que seus moldes sejam convenientemente manipulados, principalmente em relação ao tempo de vazamento do gesso Abstract in english The purpose of this research was to make a comparative study between different systems of impression materials, such as polysulfide, condensation and addition-curing silicones, using a new non-destructive technique of evaluation, and consequently clinically applicable. After obtaining three element [...] nickel-chromium prosthesis, three-dimensional replicas of the space between the restoration and the prepared tooth were made, using a condensation curing silicone. These replicas were microscopically evaluated. The results showed that, although some materials presented a superior behavior, as Permlastic and Extrude, other tested materials had an acceptable clinical behavior provided that their molds had been properly manipulated, specially regarding the time of cast pouring

  18. Physical and chemical regularities of obtaining heat resistant and radiation resistant polymer materials based on polyblend

    International Nuclear Information System (INIS)

    Full text : One of the requirements to elastomer polymer materials, based on polyblend is their resistance to heat and radiation. Elastomeric materials are widely used in nuclear technology. Nowadays, the destruction of elastomeric materials in exploitation conditions is actual, despite the number of their investigations, which were carried out in last decades

  19. Antimicrobial Effect of Zataria Multiflora Extract in Comparison with Chlorhexidine Mouthwash on Experimentally Contaminated Orthodontic Elastomeric Ligatures

    Science.gov (United States)

    Aghili, Hossein; Jafari Nadoushan, Abbas Ali; Herandi, Vahid

    2015-01-01

    Objectives: Long-term use of orthodontic appliances and fixation ligatures creates a favorable environment for the accumulation of oral normal microflora and increases the risk of enamel demineralization and periodontal disease. The aim of this study was to compare the antimicrobial effects of Zataria Multiflora extract and 0.2% chlorhexidine (CHX) mouthwash on experimentally contaminated orthodontic elastomeric ligatures. Materials and Methods: In this lab trial study, Iranian and foreign-made elastomeric ligatures were experimentally contaminated in Streptococcus mutans, Enterococcus faecalis and Candida albicans suspensions. Ligatures were then decontaminated using 0.2% CHX as the control, 0.5 mg/ml Zataria multiflora extract mouthwashes as the test and phosphate buffered saline (PBS) as the negative control for one hour. Antimicrobial properties of both solutions were evaluated by comparing the mean viable bacterial cell count on both rings after decontamination, using SPSS version 15 software. Results: The mean viable bacterial cell count on Iranian ligatures was greater than that on foreign-made ligatures before disinfection (P=0.001), however this difference for C. albicans was not statistically significant (P=0.061). Chlorhexidine mouthwash completely eliminated all tested microorganisms attached to both elastomeric rings, but Zataria extract was only capable of completely eliminating C. albicans from both ligatures. Statistically significant differences were found in viable bacterial counts on both ligatures before and after disinfection with Zataria extract (P=0.0001). Conclusion: Zataria multiflora extract has antimicrobial properties and can be used for disinfection of elastomeric ligatures. In vivo studies are required to evaluate the efficacy of the incorporation of this herbal extract in mouthwashes for orthodontic patients.

  20. Development of Remote Hanford Connector Gasket Replacement Tooling for the Savannah River Site's Defense Waste Processing Facility

    International Nuclear Information System (INIS)

    The Savannah River Site's (SRS) Defense Waste Processing Facility (DWPF) requested development of tooling and equipment to remotely replace gaskets in mechanical Hanford connectors to reduce personnel radiation exposure as compared to the current hands-on method. It is also expected that radiation levels will continually increase As future higher activity waste streams are treated. The facility is well equipped with compressed air, two master-slave manipulators (MSM's) and an electro-mechanical manipulator (EMM) arm for operation of the remote tools in the work cell proposed for remotely changing the gaskets. In order to perform all of the tasks required to remotely replace Hanford connector gaskets several operations must be performed remotely, including removal of the spent gasket and retaining ring, loading the new retaining ring and gasket into the installation tool and installation of the new gasket into the Hanford connector. The Savannah River National Laboratory, SRNL developed and tested multiple tools to perform all of the necessary tasks. Removal of retaining rings from horizontal and vertical connectors is performed by separate air actuated retaining ring removal tools and is manipulated in the cell by the MSM. A new retaining ring is then placed on a platform, rotated under the conical loading tool and raised and compressed into the gasket installation tool by two linear slides actuated by air cylinders. The gasket installation tool is then pressed against installation tool is then pressed against the gasket sealing surface of the Hanford connector using an MSM. Actuation of a custom air cylinder overcomes the force of several different springs to align and fix the installation tool relative to the Hanford connector and seats the retaining ring and gasket. All of the tools are located on a custom work table with a pneumatic valve station that directs compressed air to the desired tool and vents the tools as needed. On July 17 and 29, 2008 the Remote Gasket Replacement Tooling was successfully demonstrated in the Remote Equipment Decontamination Cell, REDC at the DWPF of The Savannah River Site. (authors)

  1. Elastomeric microfluidic diode and rectifier work with Newtonian fluids

    OpenAIRE

    Liu, John; Chen, Yan; Taylor, Clive R.; Scherer, Axel; Kartalov, Emil P.

    2009-01-01

    We report on two microfluidic elastomeric autoregulatory devices—a diode and a rectifier. They exhibit physically interesting and complex nonlinear behaviors (saturation, bias-dependent resistance, and rectification) with a Newtonian fluid. Due to their autoregulatory properties, they operate without active external control. As a result, they enable increased microfluidic device density and overall system miniaturization. The demonstrated diode and rectifier would also be useful components ...

  2. Pigment effect on the long term elasticity of elastomeric ligatures

    Scientific Electronic Library Online (English)

    Érika de Oliveira Dias de, Macêdo; Fabrício Mezzomo, Collares; Vicente Castelo Branco, Leitune; Susana Maria Werner, Samuel; Carmen Beatriz Borges, Fortes.

    2012-06-01

    Full Text Available OBJECTIVE: To evaluate the response of elastomeric ligatures in several colors for a 4 mm traction over time. METHODS: Morelli® elastomeric ligatures, were submitted to traction forces using two rods of circular cross section, until a 4 mm distance was reached, matching the approximate diameter of a [...] n upper central incisor bracket of the same manufacturer. The ligatures were kept in artificial saliva immersion at 37 ºC. Forces levels were measured immediately (0 h), 2, 4, 6, 8, 10, 12, 24, 48, 72, 96 hours, 1, 2, 3, 4 weeks and results were submitted to two-way repeated-measures ANOVA statistical analysis. RESULTS: The gray samples showed the higher initial values of tensile strength. The lowest values were presented by purple, light pink, green, black and red groups. The greater tensile strength instability was presented by red, black, silver, green and gray groups. The greater tensile strength stability was presented by deep pink, dark blue, blue, purple and light pink groups. CONCLUSION: Elastomeric ligatures do not present stable behavior when suffering traction forces over time and different colors display different behaviors. Deep pink, dark blue, blue, purple and light pink groups, displayed the most stable forces, suggesting that they should be used during the treatment to obtain constant forces.

  3. Citotoxicity of nonlatex elastomeric ligatures of orthodontic use

    Scientific Electronic Library Online (English)

    Rogério, Lacerda-Santos; Alane Sonally Benício do, Nascimento; Allana Roberta Bandeira, Pereira; Paulyana Pryscilla de Melo, Freire; Matheus Melo, Pithon; Maria Teresa Villela, Romanos.

    2015-03-01

    Full Text Available The aim of this study is to evaluate cytotoxicity between polyurethane and non-latex orthodontic elastomeric ligatures. Seven elastomeric ligatures of black-coloured from different manufactures (3 non-latex, 3 polyurethane and 1 latex) were divided into 7 groups of 10 elastics each: Group UK (nonlat [...] ex, 3M Unitek), Group TP (nonlatex, TP Orthodontics), Group AO (nonlatex, American Orthodontics), Group O (Polyurethane, OrthoSource), Group M (Polyurethane, Morelli), Group TD (Polyurethane, Tecnident) and Group TC (latex - Control, TP Orthodontics). The cytotoxicity essay was performed using cell cultures (L-929 line cells, mouse fibroblast) that were submitted to the cell viability test with neutral red ("dye-uptake") at 1, 2, 3, 7 and 28 days. Analysis of variance (ANOVA) with 1-way analysis followed by the Tukey post hoc test were employed (p.05). There was a statistically differences (p.05) between the groups O, M and TD at in all experimental times. It can be concluded that the nonlatex elastomeric ligatures of Unitek, TP Orthodontics, and American Orthodontics showed higher cell viability compared to others ligatures.

  4. Response of elastomeric packaging components to a corrosive simulant mixed waste

    International Nuclear Information System (INIS)

    The purpose of hazardous and radioactive materials packaging is to enable these materials to be transported without posing a threat to the health or property of the general public. To achieve this aim, regulations in the US have been written establishing general design requirements for such packagings. While no regulations have been written specifically for mixed waste packaging, regulations for the constituents of mixed wastes, i.e., hazardous and radioactive substances, have been codified by the US Department of Transportation and the US Nuclear Regulatory Commission. Based on these national requirements, a Chemical Compatibility Testing Program was developed in the Transportation Systems Department at SNL. In this paper, the authors present the results of Part B of the second phase of this testing program. The first phase screened five liner materials and six seal materials towards four simulant mixed wastes. Part A of the second phase involved the comprehensive testing of five candidate liner materials to an aqueous Hanford Tank simulant mixed waste. Part B involved similar testing on elastomeric materials, ethylene-propylene and butadiene-acrylonitrile rubber. The comprehensive testing protocol involved exposing the respective materials to a matrix of four gamma radiation doses (?1, 3, 6, and 40 kGy), three temperatures (18, 50, and 60 C), and four exposure times (7, 14, 28, and 180 days). Following their exposure to these combinations of conditions, the materials were evaluated by measuring six material properties. These properties were specific gravity, dimensional changes, hardness, vapor transport rates, compression set, and mechanical properties

  5. Seismic response analysis of base isolated structures with high damping elastomeric bearings

    International Nuclear Information System (INIS)

    Seismic response analysis of base-isolated structures with high damping elastomeric bearings is described in this paper. Emphasis is placed on the adaptation of a nonlinear constitutive model for the isolation bearing together with the treatment of foundation embedment for the soil-structure-interaction analysis. The constitutive model requires six input parameters derived from bearing experimental data under sinusoidal loading. The characteristic behavior of bearing, such as the variation of shear modulus and material damping with the change of maximum shear deformation, can be captured closely by the formulation. In the treatment of soil embedment a spring method is utilized to evaluate the foundation input motion as well as soil stiffness and damping. The above features have been incorporated into a three-dimensional system response program, SISEC, developed at Argonne National Laboratory. Sample problems are presented to illustrate the relative response of isolated and unisolated structures

  6. Optimization of fractional composition of the excipient in the elastomeric covering for asphalt highways

    Directory of Open Access Journals (Sweden)

    E. M. Nurullaev

    2013-04-01

    Full Text Available The computational method of optimum fractional composition of a dispersible filler of polymeric composite on the basis of three-dimensionally linked elastomer is developed according to non-linear programming. The coefficient of dynamic viscosity of polymeric suspension or the initial module of a viscoelasticity of the join solidification low-molecular rubbers with the final functional groups, filled by many fractional dioxide of silicon are considered as criteria of optimization. Influence of the limiting volume filling on energy of mechanical destruction was investigated. The elastomeric material is offered for use as a covering of asphalt highways in the form of a frost-proof waterproofing layer, which allowing multiply to increase operating properties.

  7. Crystallization Induced Structuring and Properties of CEC-P-CEC Elastomeric Multiblock Terpolymers

    Science.gov (United States)

    Guillermo Alfonzo, C.; Fleury, Guillaume; Bates, Frank S.; Chaffin, Kimberly A.

    2010-03-01

    We report the synthesis and characterization of a new class of block copolymer based thermoplastic elastomers that microphase separate in response to block crystallization. Five relatively monodisperse CEC-P-CEC block terpolymers containing glassy poly(cyclohexyl-ethylene) (C), semi-crystalline poly(ethylene) (E) and elastomeric poly(ethylene-alt-propylene) (P) were synthesized in a heptablock architecture by anionic polymerization and catalytic hydrogenation. Microphase segregation is induced from a homogeneous state by E crystallization, resulting in a bicontinuous morphology with CEC and P sub-structures leading to a useful combination of tensile modulus, tensile strength and elastic recovery. This molecular design decouples the material processing temperature from copolymer composition and molecular weight due to a favorable combination of block-block interactions in the melt state.

  8. PRELIMINARY REPORT: EFFECTS OF IRRADIATION AND THERMAL EXPOSURE ON ELASTOMERIC SEALS FOR CASK TRANSPORTATION AND STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Verst, C.; Skidmore, E.; Daugherty, W.

    2014-05-30

    A testing and analysis approach to predict the sealing behavior of elastomeric seal materials in dry storage casks and evaluate their ability to maintain a seal under thermal and radiation exposure conditions of extended storage and beyond was developed, and initial tests have been conducted. The initial tests evaluate the aging response of EPDM elastomer O-ring seals. The thermal and radiation exposure conditions of the CASTOR® V/21 casks were selected for testing as this cask design is of interest due to its widespread use, and close proximity of the seals to the fuel compared to other cask designs leading to a relatively high temperature and dose under storage conditions. A novel test fixture was developed to enable compression stress relaxation measurements for the seal material at the thermal and radiation exposure conditions. A loss of compression stress of 90% is suggested as the threshold at which sealing ability of an elastomeric seal would be lost. Previous studies have shown this value to be conservative to actual leakage failure for most aging conditions. These initial results indicate that the seal would be expected to retain sealing ability throughout extended storage at the cask design conditions, though longer exposure times are needed to validate this assumption. The high constant dose rate used in the testing is not prototypic of the decreasingly low dose rate that would occur under extended storage. The primary degradation mechanism of oxidation of polymeric compounds is highly dependent on temperature and time of exposure, and with radiation expected to exacerbate the oxidation.

  9. Storage containers for radioactive material

    Science.gov (United States)

    Groh, Edward F. (Naperville, IL); Cassidy, Dale A. (Valparaiso, IN); Dates, Leon R. (Elmwood Park, IL)

    1981-01-01

    A radioactive material storage system for use in the laboratory having a flat base plate with a groove in one surface thereof and a hollow pedestal extending perpendicularly away from the other surface thereof, a sealing gasket in the groove, a cover having a filter therein and an outwardly extending flange which fits over the plate, the groove and the gasket, and a clamp for maintaining the cover and the plate sealed together, whereby the plate and the cover and the clamp cooperate to provide a storage area for radioactive material readily accessible for use or

  10. Flexible Connection Elastomeric Rubber as a Pounding Resisting Element between Two Adjacent Building

    Directory of Open Access Journals (Sweden)

    James Jatmiko Oetomo

    2011-11-01

    Full Text Available Flexible Connection Elastomeric Rubber as a Pounding Resisting Element between Two Adjacent Buildings To solve pounding problem of two adjacent buildings, structural designer usually employs a dilatation between the structures or make the two structures as a monolith structure. Other alternative is by using an elastomeric rubber as a pounding resisting element between the two structures. Effectiveness in applying elastomeric rubber component as flexible connection of two adjacent structures is the main focus of this paper. Various simulations such as structure models, earthquake excitations and openings in gap element are studied. Observation of maximum structural responses will be performed for structure model with elastomeric rubber in comparison with (1 monolith structure model and (2 structure model with rigid element (steel element. Simulation results show that application of elastomeric rubbercomponent to prevent structures from pounding problem provides advantages especially in reducing internal forces in the shorter building. However, it slightly increases displacement of both structures.

  11. Micromechanical damage and fracture in elastomeric polymers

    Science.gov (United States)

    Heyden, Stefanie

    This thesis aims at a simple one-parameter macroscopic model of distributed damage and fracture of polymers that is amenable to a straightforward and efficient numerical implementation. The failure model is motivated by post-mortem fractographic observations of void nucleation, growth and coalescence in polyurea stretched to failure, and accounts for the specific fracture energy per unit area attendant to rupture of the material. Furthermore, it is shown that the macroscopic model can be rigorously derived, in the sense of optimal scaling, from a micromechanical model of chain elasticity and failure regularized by means of fractional strain-gradient elasticity. Optimal scaling laws that supply a link between the single parameter of the macroscopic model, namely the critical energy-release rate of the material, and micromechanical parameters pertaining to the elasticity and strength of the polymer chains, and to the strain-gradient elasticity regularization, are derived. Based on optimal scaling laws, it is shown how the critical energy-release rate of specific materials can be determined from test data. In addition, the scope and fidelity of the model is demonstrated by means of an example of application, namely Taylor-impact experiments of polyurea rods. Hereby, optimal transportation meshfree approximation schemes using maximum-entropy interpolation functions are employed. Finally, a different crazing model using full derivatives of the deformation gradient and a core cut-off is presented, along with a numerical non-local regularization model. The numerical model takes into account higher-order deformation gradients in a finite element framework. It is shown how the introduction of non-locality into the model stabilizes the effect of strain localization to small volumes in materials undergoing softening. From an investigation of craze formation in the limit of large deformations, convergence studies verifying scaling properties of both local- and non-local energy contributions are presented.

  12. In vitro study of cytotoxicity of orthodontic elastomeric ligatures

    Scientific Electronic Library Online (English)

    Rogério Lacerda dos, Santos; Matheus Melo, Pithon; Paulyana Pryscilla de Melo, Freire; Maria Teresa Villela, Romanos.

    2012-08-01

    Full Text Available This study investigated the cytotoxicity of crystal-coloured orthodontic elastomeric ligatures of polyurethane. Six ligatures from distinct manufactures were divided into 6 groups of 10 elastics each: Groups P1, P2, P3, P4, P5 and P6 (Polyurethane). The cytotoxicity essay was performed using L-929 l [...] ine cells, which were submitted to the cell viability test with neutral red ("dye-uptake") at time intervals of 1, 2, 3, 7 and 28 days. Analysis of variance (ANOVA) with multiple comparisons and Tukey's test were used (p

  13. Elastic buckling of AlN ribbons on elastomeric substrate

    International Nuclear Information System (INIS)

    For optoelectronic applications requiring unconventional substrates, use of flexible forms of semiconductors may be inevitable. We have fabricated a flexible form of single crystalline AlN ribbons with periodic and wavelike structures on an elastomeric substrate. Single crystalline AlN films were grown on Si (111) substrate using high vacuum unbalanced magnetron sputtering. Crystallinity of the AlN films was confirmed with x-ray diffraction and pole figure. The AlN ribbons were transferred to a prestrained (3.1%) elastomeric substrate and the resulting ''wavy'' ribbons on the substrate were flexible up to 30% strain without any crack formation on the surface. As the film thickness changed from 300 to 900 nm, the periods of the waves varied from 95 to 277 ?m, which were within a 10% error of the calculated values. When we applied more than 30% strain, mechanical instability, such as the failure of AlN ribbons due to the cracks on the surface and the merged ribbons, was observed

  14. In vitro study of cytotoxicity of orthodontic elastomeric ligatures

    Directory of Open Access Journals (Sweden)

    Rogério Lacerda dos Santos

    2012-08-01

    Full Text Available This study investigated the cytotoxicity of crystal-coloured orthodontic elastomeric ligatures of polyurethane. Six ligatures from distinct manufactures were divided into 6 groups of 10 elastics each: Groups P1, P2, P3, P4, P5 and P6 (Polyurethane. The cytotoxicity essay was performed using L-929 line cells, which were submitted to the cell viability test with neutral red ("dye-uptake" at time intervals of 1, 2, 3, 7 and 28 days. Analysis of variance (ANOVA with multiple comparisons and Tukey's test were used (p < .05. There were statistical differences (p < .05 in cell viability between Groups P1, P4, P2 and P3, and Groups P5 and P6 at 1 and 2 days. All elastomeric ligatures were considered suitable for clinical use. The hypothesis was accepted, the P5 and P6 elastomers and the processing route of injection molding for these ligatures showed the lowest cell viability, due the temperature and pressure distinct in the processing of these elastomers.

  15. Microsphere-assisted fabrication of high aspect-ratio elastomeric micropillars and waveguides

    Science.gov (United States)

    Paek, Jungwook; Kim, Jaeyoun

    2014-02-01

    High aspect-ratio micropillars are in strong demand for microtechnology, but their realization remains a difficult challenge, especially when attempted with soft materials. Here we present a direct drawing-based technique for fabricating micropillars with poly(dimethylsiloxane). Despite the material’s extreme softness, our technique enables routine realization of micropillars exceeding 2,000??m in height and 100 in aspect-ratio. It also supports in situ integration of microspheres at the tips of the micropillars. As a validation of the new structure’s utility, we configure it into airflow sensors, in which the micropillars and microspheres function as flexible upright waveguides and self-aligned reflectors, respectively. High-level bending of the micropillar under an airflow and its optical read-out enables mm?s-1 scale-sensing resolution. This new scheme, which uniquely integrates high aspect-ratio elastomeric micropillars and microspheres self-aligned to them, could widen the scope of soft material-based microdevice technology.

  16. Damage of Elastomeric Matrix Composites (EMC-rubbers) Under Static Loading Conditions: Experimental and Numerical Study

    International Nuclear Information System (INIS)

    Elastomeric matrix composites (EMC-rubbers) are considered as isotropic hyper elastic incompressible materials under static loading conditions. As a rubber material element cannot be extended to an infinite stretch ratio, a damage mechanism at large strain is considered. The phenomenon of cavitation plays an important role in the damage of EMCs and influences the toughening mechanism of rubber-modified plastics. Indeed, cavitation in elastomers is thought to be initiated from flaws, which grow primarily due to a hydrostatic tensile stress and ahead of the crack; there will not only be a high stress perpendicular to the plane of the crack but also significant stress components in the other direction. However, there exists historically much discussion on the evolution of the cavitation in elastomers under monotonic and/or static solicitation. Mainly, cavitation instability occurs when the stress levels are sufficiently high so that the void expansion rate becomes infinitely large. Many research works have been performed to understand the effects of rubber cavitation on toughening of plastics. In fact, the cavitation phenomenon is not well known in detail. The most popular idea states that the cavitation is related to the existence of the gas bubbles trapped in the material during the production stage and the growing of the cavities would then be the result of the growing gas bubbles. Further, instable failure mechanism at the end of the cavitation is not well known too.d of the cavitation is not well known too.

  17. Shape-Memory Polymers Based on Fatty Acid-Filled Elastomeric Ionomers

    Science.gov (United States)

    Izzo, Elise; Weiss, Robert

    2009-03-01

    Shape memory polymers (SMPs) have applications as medical devices, actuators, sensors, artificial muscles, switches, smart textiles, and self-deployable structures. All previous design of SMPs has involved synthesizing new polymers or modifying existing polymers. This paper describes a new type of SMP based on blends of an elastomeric ionomer and low molar mass fatty acids or their salts (FAS). Shape memory elastomers were prepared from mixtures of a sulfonated EPDM ionomer and various amounts of a FAS (e.g., zinc stearate, zinc oleate, and various aliphalic acids). Nanophase separation of the metal sulfonate groups provided the ``permanent'' crosslinks, while sub-microscopic crystals of the low molecular weight FAS provided a physical crosslink needed for the temporary shape. The material was deformed above the melting point of the FAS and the new shape was fixed by cooling the material while under stress to below the melting point of the FAS. Polar interactions between the ionomer and the FAS stabilized the dispersion of the FAS in the polymer and provided the continuity between the phases that allowed the crystals of the FAS to provide a second network of physical crosslinks. The temporary shape was erased and the material returned to the primary shape by heating above the melting point of the FAS.

  18. Avaliação das tensões liberadas por elásticos ortodônticos em cadeia: estudo in vitro / Assessment of force decay in orthodontic elastomeric chains: an in vitro study

    Scientific Electronic Library Online (English)

    Claudia, Kochenborger; Dayanne Lopes da, Silva; Ernani Menezes, Marchioro; Diogo Antunes, Vargas; Luciane, Hahn.

    2011-12-01

    Full Text Available INTRODUÇÃO: os materiais elastoméricos são considerados importantes fontes de força para a movimentação ortodôntica. OBJETIVO: avaliar a liberação de tensões de quatro marcas comerciais de elásticos ortodônticos em cadeia (Morelli, Ormco, TP e Unitek), em função do tempo, quando mantidas tensionadas [...] por uma força inicial de 150g e imersas em saliva artificial a 37ºC. MÉTODOS: os elásticos em cadeia foram tensionados entre pinos de aço, fixados em uma placa de resina acrílica à distância de 15mm (Morelli e TP) e de 16mm (Unitek e Ormco), ambas medidas correspondendo a uma força de 150g. A leitura da quantidade de tensão liberada pelos elásticos foi realizada com um dinamômetro nos intervalos 30 minutos, 7, 14 e 21 dias. Os dados obtidos foram submetidos à análise de variância (ANOVA) (p Abstract in english INTRODUCTION: Elastomeric materials are considered important sources of orthodontic forces. OBJECTIVE: To assess force degradation over time of four commercially available orthodontic elastomeric chains (Morelli, Ormco, TP and Unitek). METHODS: The synthetic elastics were submerged in 37 ºC syntheti [...] c saliva and stretched by a force of 150 g (15 mm - Morelli and TP; 16mm - Unitek and Ormco). With a dynamometer, the delivered force was evaluated at different intervals: 30 minutes, 7 days, 14 days and 21 days. The results were subjected to ANOVA and Tukey's test. RESULTS: There was a force decay between 19% to 26.67% after 30 minutes, and 36.67% to 57% after 21 days of activation. CONCLUSIONS: TP elastomeric chains exhibited the smallest percentage of force decay, with greater stability at all time intervals tested. Meanwhile, the Unitek chains displayed the highest percentage of force degradation, and no statically significant difference was found in force decay between Ormco and Morelli elastomeric chains during the study period.

  19. Structural evaluation of Marman V-band coupling and flange with conoseal gasket

    Science.gov (United States)

    Oates, J. H.

    1972-01-01

    Results are described of a development test program directed at evaluating the structural capabilities of the Marman V-band coupling and flange with conoseal gasket. The intended end use was for the 75K NERVA flight engine propellant lines. Of major importance in the structural evaluation was the ability to predict stresses throughout the assembly for a variety of loading conditions. Computer finite element analysis was used to predict these stresses but, for the subject configuration, large uncertainties were introduced in modeling the complex geometry and boundary conditions. The purpose of the structural tests was to obtain actual stresses and deflections for correlation with, and updating of the finite element model. Results of the incomplete test program are inconclusive with respect to determining suitability for use on the NERVA engine.

  20. Modified Sierpinski Gasket Patch Antenna for UMTS and 2.4/5.2 WLAN

    Directory of Open Access Journals (Sweden)

    Y. E. Ali

    2013-05-01

    Full Text Available A modified Sierpinski Gasket fractal antenna for multiband application is proposed in this paper. The modified ground plane and the microstrip feed are used to obtain the wider bandwidth at the resonance frequency. The antenna is designed and printed on two layers FR-4 substrate (?r=4.4 and h=1.6 mm to cover the UMTS and 2.4/5.2 WLAN. The radiation pattern of the proposed antenna is similar to an omnidirectional. The proposed antenna has maximum gain of 1.88, 1.6, 4.31 dB at 2, 2.4, 5.2 GHz, respectively The properties of the antenna such as return losses, radiation pattern, input resistance and gain are determined via numerical CST Microwave Studio 2010 software.

  1. Adhesion of elastomeric surfaces structured with micro-dimples

    Science.gov (United States)

    Nanni, Gabriele; Fragouli, Despina; Ceseracciu, Luca; Athanassiou, Athanassia

    2015-01-01

    Topography has a dominant role in determining the adhesion properties of a surface. In this work we explore how arrays of micron-sized dimples can alter the adhesion performance of elastomeric surfaces. We study the effect of the dimple surface coverage, showing that the dimples act both as passive suction devices, allowing to exceed the adhesion performance of untextured surfaces, and crack-like defects, generating stress concentration at the edge of the contact area between the surface of the sample and a flat surface. Interestingly, our results reveal that the suction effect generated by the negative pressure produced by the dimples can be effectively tuned by adjusting their depth. These findings have significant relevance for the fabrication of adhesive systems in which selective adhesion to objects with small difference in weight is required.

  2. Elastomeric polymer resonant waveguide grating based pressure sensor

    Science.gov (United States)

    Song, Fuchuan; Jou Xie, Antonio; Seo, Sang-Woo

    2014-06-01

    In this paper, we demonstrate an elastomeric polymer resonant waveguide grating structure to be used as a pressure sensor. The applied pressure is measured by optical resonance spectrum peak shift. The sensitivity—as high as 86.74 pm psi-1 or 12.58 pm kPa-1—has been experimentally obtained from a fabricated sensor. Potentially, the sensitivity of the demonstrated sensor can be tuned to different pressure ranges by the choices of elastic properties and layer thicknesses of the waveguide and cladding layers. The simulation results agree well with experimental results and indicate that the dominant effect on the sensor is the change of grating period when external pressure is applied. Based on the two-dimensional planar structure, the demonstrated sensor can be used to measure applied surface pressure optically, which has potential applications for optical ultrasound imaging and pressure wave detection/mapping.

  3. Elastomeric polymer resonant waveguide grating based pressure sensor

    International Nuclear Information System (INIS)

    In this paper, we demonstrate an elastomeric polymer resonant waveguide grating structure to be used as a pressure sensor. The applied pressure is measured by optical resonance spectrum peak shift. The sensitivity—as high as 86.74 pm psi?1 or 12.58 pm kPa?1—has been experimentally obtained from a fabricated sensor. Potentially, the sensitivity of the demonstrated sensor can be tuned to different pressure ranges by the choices of elastic properties and layer thicknesses of the waveguide and cladding layers. The simulation results agree well with experimental results and indicate that the dominant effect on the sensor is the change of grating period when external pressure is applied. Based on the two-dimensional planar structure, the demonstrated sensor can be used to measure applied surface pressure optically, which has potential applications for optical ultrasound imaging and pressure wave detection/mapping

  4. Microfluidic fabrication and micromechanics of permeable and impermeable elastomeric microbubbles.

    Science.gov (United States)

    Duncanson, Wynter J; Kodger, Thomas E; Babaee, Sahab; Gonzalez, Grant; Weitz, David A; Bertoldi, Katia

    2015-03-24

    We use droplet microfluidics to produce monodisperse elastomeric microbubbles consisting of gas encapsulated in a polydimethylsiloxane shell. These microbubbles withstand large, repeated deformations without rupture. We perform ?N-scale compression tests on individual microbubbles and find their response to be highly dependent on the shell permeability; during deformation, the pressure inside impermeable microbubbles increases, resulting in an exponential increase in the applied force. Finite element models are used to interpret and extend these experimental results enabling the design and development of deformable microbubbles with a predictable mechanical response. Such microbubbles can be designed to repeatedly transit through the narrow constrictions found in a porous medium functioning as probes of the local pressure. PMID:25730159

  5. Modification of PVC compounds with butadiene-acrylonitrile elastomers

    OpenAIRE

    Stabik, J.; Rojek, M.

    2006-01-01

    Purpose: The purpose of the paper is to present the research programme on influence of acrylonitrile-butadiene copolymers on properties of plasticized polyvinylchloride as window gaskets material.Design/methodology/approach: Short literature review concerning application of modified PVC as gasket material was presented. In experimental part two types of acrylonitrile-butadiene copolymers were used as elastomeric plasticizers. Compounds with fifteen different levels of modifiers content (up to...

  6. Butadiene-acrylonitrile elastomers as PVC modifiers

    OpenAIRE

    Rojek, M.; Stabik, J.

    2007-01-01

    Purpose: The purpose of the paper is to present the results of research programme on influence of acrylonitrile-butadiene copolymers on plasticized polyvinylchloride compounds used as window gasket material.Design/methodology/approach: Short review concerning application of modified plasticized PVC compounds as gasket material was presented. In experimental part two types of acrylonitrile-butadiene copolymers were used as elastomeric plasticizers for PVC. Formulations with fifteen dif...

  7. Gecko gaskets for self-sealing and high-strength reversible bonding of microfluidics.

    Science.gov (United States)

    Wasay, A; Sameoto, D

    2015-07-01

    We report in this work a novel reversible bonding technique for elastomeric microfluidic devices by integrating gecko-inspired dry adhesives with microfluidic channels which greatly enhances the bonding strength of reversibly sealed channels. The concept is applicable to nearly any elastomer and can be used to bond against any smooth surface which allows for van der Waals interactions. It does not require any solvents or glues or sources for plasma activation or thermal-compressive loading to aid the bonding process and is achievable at zero extra cost. We also demonstrate a quick fabrication technique involving soft master thermo-compressive molding of these microfluidic devices with thermoplastic elastomers. The resultant devices can be used for both pressure driven and non-pressure driven flows. We report the maximum contained pressure of these devices manufactured from two grades of styrene ethylene butylene styrene (SEBS) by conducting a burst pressure test with various substrates. PMID:26016928

  8. In vitro evaluation of force degradation of elastomeric chains used in Orthodontics

    Scientific Electronic Library Online (English)

    André, Weissheimer; Arno, Locks; Luciane Macedo de, Menezes; Adriano Ferreti, Borgatto; Carla D' Agostini, Derech.

    2013-02-01

    Full Text Available OBJETIVO: analisar, in vitro, a degradação de força, ao longo do tempo, de elastômeros das marcas comerciais American Orthodontics, Morelli, Ormco e TP Orthodontics. MÉTODOS: a amostra constituiu-se de 80 segmentos de elastômeros em cadeia fechada na cor cinza, divididos em quatro grupos, conforme o [...] fabricante. A distensão foi padronizada em 21mm, com liberação de força inicial variando de 300 a 370g de força. As amostras foram mantidas em saliva artificial em temperatura constante de 37ºC, e a força avaliada nos seguintes intervalos: inicial, 1h, 3h, 5h, 7h, 9h, 1 dia, 7 dias, 14 dias, 21 dias, 28 dias e 35 dias. RESULTADOS: houve diferença estatisticamente significativa na degradação de força entre os grupos avaliados, sendo que no primeiro dia houve perda de 50 a 55% em relação à força inicial. Os valores médios de força em 35 dias variaram de 122 a 148g. CONCLUSÃO: todas as marcas comerciais apresentaram degradação de força ao longo do tempo, sendo que na primeira hora a perda de força esteve entre 59 e 69% da força inicial. Porém, como existe variação dessa degradação dependendo da marca comercial, estudos como esses são importantes para orientação do uso desses elastômeros. Abstract in english OBJECTIVE: To analyze the in vitro force degradation of four different brands of elastomeric chains: American Orthodontics, Morelli, Ormco and TP Orthodontics. METHODS: The sample consisted of 80 gray elastomeric chains that were divided into four groups according to their respective manufacturers. [...] Chain stretching was standardized at 21 mm with initial force release ranging from 300 g to 370 g. The samples were kept in artificial saliva at a constant temperature of 37°C and the degradation force was recorded at the following time intervals: initial, 1, 3, 5, 7 and 9 hours, and 1, 7, 14, 21, 28, and 35 days. RESULTS: There was a statistically significant difference between the groups regarding the force degradation, mainly within the first day, as a force loss of 50-55% was observed during that time in relation to the initial force. The force delivered at 35 days ranged from 122 g to 148 g. CONCLUSION: All groups showed force degradation over time, regardless of their trademarks, a force loss of 59-69% was observed in the first hour compared to baseline. However, because the variation in force degradation depends on the trademark, studies such as the present one are important for guiding the clinical use of these materials.

  9. In vitro evaluation of force degradation of elastomeric chains used in Orthodontics

    Directory of Open Access Journals (Sweden)

    André Weissheimer

    2013-02-01

    Full Text Available OBJECTIVE: To analyze the in vitro force degradation of four different brands of elastomeric chains: American Orthodontics, Morelli, Ormco and TP Orthodontics. METHODS: The sample consisted of 80 gray elastomeric chains that were divided into four groups according to their respective manufacturers. Chain stretching was standardized at 21 mm with initial force release ranging from 300 g to 370 g. The samples were kept in artificial saliva at a constant temperature of 37°C and the degradation force was recorded at the following time intervals: initial, 1, 3, 5, 7 and 9 hours, and 1, 7, 14, 21, 28, and 35 days. RESULTS: There was a statistically significant difference between the groups regarding the force degradation, mainly within the first day, as a force loss of 50-55% was observed during that time in relation to the initial force. The force delivered at 35 days ranged from 122 g to 148 g. CONCLUSION: All groups showed force degradation over time, regardless of their trademarks, a force loss of 59-69% was observed in the first hour compared to baseline. However, because the variation in force degradation depends on the trademark, studies such as the present one are important for guiding the clinical use of these materials.OBJETIVO: analisar, in vitro, a degradação de força, ao longo do tempo, de elastômeros das marcas comerciais American Orthodontics, Morelli, Ormco e TP Orthodontics. MÉTODOS: a amostra constituiu-se de 80 segmentos de elastômeros em cadeia fechada na cor cinza, divididos em quatro grupos, conforme o fabricante. A distensão foi padronizada em 21mm, com liberação de força inicial variando de 300 a 370g de força. As amostras foram mantidas em saliva artificial em temperatura constante de 37ºC, e a força avaliada nos seguintes intervalos: inicial, 1h, 3h, 5h, 7h, 9h, 1 dia, 7 dias, 14 dias, 21 dias, 28 dias e 35 dias. RESULTADOS: houve diferença estatisticamente significativa na degradação de força entre os grupos avaliados, sendo que no primeiro dia houve perda de 50 a 55% em relação à força inicial. Os valores médios de força em 35 dias variaram de 122 a 148g. CONCLUSÃO: todas as marcas comerciais apresentaram degradação de força ao longo do tempo, sendo que na primeira hora a perda de força esteve entre 59 e 69% da força inicial. Porém, como existe variação dessa degradação dependendo da marca comercial, estudos como esses são importantes para orientação do uso desses elastômeros.

  10. Static and cyclic mechanical loading of mesenchymal stem cells on elastomeric, electrospun polyurethane meshes.

    Science.gov (United States)

    Cardwell, Robyn D; Kluge, Jonathan A; Thayer, Patrick S; Guelcher, Scott A; Dahlgren, Linda A; Kaplan, David L; Goldstein, Aaron S

    2015-07-01

    Biomaterial substrates composed of semi-aligned electrospun fibers are attractive supports for the regeneration of connective tissues because the fibers are durable under cyclic tensile loads and can guide cell adhesion, orientation, and gene expression. Previous studies on supported electrospun substrates have shown that both fiber diameter and mechanical deformation can independently influence cell morphology and gene expression. However, no studies have examined the effect of mechanical deformation and fiber diameter on unsupported meshes. Semi-aligned large (1.75??m) and small (0.60??m) diameter fiber meshes were prepared from degradable elastomeric poly(esterurethane urea) (PEUUR) meshes and characterized by tensile testing and scanning electron microscopy (SEM). Next, unsupported meshes were aligned between custom grips (with the stretch axis oriented parallel to axis of fiber alignment), seeded with C3H10T1/2 cells, and subjected to a static load (50?mN, adjusted daily), a cyclic load (4% strain at 0.25?Hz for 30?min, followed by a static tensile loading of 50?mN, daily), or no load. After 3 days of mechanical stimulation, confocal imaging was used to characterize cell shape, while measurements of deoxyribonucleic acid (DNA) content and messenger ribonucleic acid (mRNA) expression were used to characterize cell retention on unsupported meshes and expression of the connective tissue phenotype. Mechanical testing confirmed that these materials deform elastically to at least 10%. Cells adhered to unsupported meshes under all conditions and aligned with the direction of fiber orientation. Application of static and cyclic loads increased cell alignment. Cell density and mRNA expression of connective tissue proteins were not statistically different between experimental groups. However, on large diameter fiber meshes, static loading slightly elevated tenomodulin expression relative to the no load group, and tenascin-C and tenomodulin expression relative to the cyclic load group. These results demonstrate the feasibility of maintaining cell adhesion and alignment on semi-aligned fibrous elastomeric substrates under different mechanical conditions. The study confirms that cell morphology is sensitive to the mechanical environment and suggests that expression of select connective tissue genes may be enhanced on large diameter fiber meshes under static tensile loads. PMID:25902471

  11. A NOVEL DESIGN OF MULTIBAND SQUARE PATCH ANTENNA EMBEDED WITH GASKET FRACTAL SLOT FOR WLAN & WIMAX COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Asit K. Panda

    2012-03-01

    Full Text Available A compact multiband patch antenna embedded with gasket fractal slots is proposed in this paper. The structure consists of square patch element with modified gasket slots on both radiating edge side. The antenna is fed by 50? co-planar waveguide (CPW to make the structure purely planar. The investigation took place ranges between 1-7.5 GHz using CST MWS electromagnetic simulator. There are 3 resonant frequencies appeared at 2.45GHz, 3.6GHz & 5.6 GHz. From the return loss plot it is seen the antenna achieved the IEEE Bluetooth / WLAN (2.4-2.484 GHz, WiMAX (3.4-3.69 GHz & WIFI (5.1-5.825 GHz frequency band with -10 dB return loss and also nearly omni-directional radiation patterns achieved. The peak realized antenna gain is around 5dB in all distinct bands.

  12. Numerical study of effect of elastomeric stress absorbers on stress reduction in bone-dental implant interface

    Scientific Electronic Library Online (English)

    Ghalem, MEHDI; Abderrahmane, BELARBI; Bensmaine, MANSOURI; Zitouni, AZARI.

    2015-02-01

    Full Text Available Objective This paper focused on optimal stress distribution in the mandibular bone surrounding a dental implant and is devoted to the development of a modified Osteoplant® implant type in order to minimize stress concentration in the bone-implant interface. Material and Methods This study investiga [...] ted 0.4 mm thick layers of two elastomeric stress barriers incorporated into the dental implant using 3-D finite element analysis. Results Overall, this proposed implant provoked lower load transfer in bone-implant interface due to the effect of the elastomers as stress absorbers. The stress level in the bone was reduced between 28% and 42% for three load cases: 75 N, 60 N and 27 N in corono-apical, linguo-buccal and disto-mesial direction, respectively. Conclusion The proposed model provided an acceptable solution for load transfer reduction to the mandible. This investigation also permitted to choose how to incorporate two elastomers into the Osteoplant® implant system.

  13. Lateral buckling mechanics in silicon nanowires on elastomeric substrates.

    Science.gov (United States)

    Ryu, Seung Yoon; Xiao, Jianliang; Park, Won Il; Son, Kwang Soo; Huang, Yonggang Y; Paik, Ungyu; Rogers, John A

    2009-09-01

    We describe experimental and theoretical studies of the buckling mechanics in silicon nanowires (SiNWs) on elastomeric substrates. The system involves randomly oriented SiNWs grown using established procedures on silicon wafers, and then transferred and organized into aligned arrays on prestrained slabs of poly(dimethylsiloxane) (PDMS). Releasing the prestrain leads to nonlinear mechanical buckling processes that transform the initially linear SiNWs into sinusoidal (i.e., "wavy") shapes. The displacements associated with these waves lie in the plane of the substrate, unlike previously observed behavior in analogous systems of silicon nanoribbons and carbon nanotubes where motion occurs out-of-plane. Theoretical analysis indicates that the energy associated with this in-plane buckling is slightly lower than the out-of-plane case for the geometries and mechanical properties that characterize the SiNWs. An accurate measurement of the Young's modulus of individual SiNWs, between approximately 170 and approximately 110 GPa for the range of wires examined here, emerges from comparison of theoretical analysis to experimental observations. A simple strain gauge built using SiNWs in these wavy geometries demonstrates one area of potential application. PMID:19670847

  14. Biocide squirting from an elastomeric tri-layer film

    Science.gov (United States)

    Sonntag, Philippe; Hoerner, Pierre; Cheymol, André; Argy, Gilles; Riess, Gérard; Reiter, Günter

    2004-05-01

    Protective layers typically act in a passive way by simply separating two sides. Protection is only efficient as long as the layers are intact. If a high level of protection has to be achieved by thin layers, complementary measures need to be in place to ensure safety, even after breakage of the layer-an important issue in medical applications. Here, we present a novel approach for integrating a biocide liquid into a protective film (about 300-500 ?m thick), which guarantees that a sufficient amount of biocide is rapidly released when the film is punctured. The film is composed of a middle layer, containing the liquid in droplet-like compartments, sandwiched between two elastomeric boundary layers. When the film is punctured, the liquid squirts out of the middle layer. A theoretical model was used to determine the size and density of droplets that are necessary to ensure a sufficient quantity of biocide is expelled from an adequately elastic matrix to provide protection at the site of damage. We demonstrate the utility of this approach for the fabrication of surgical gloves.

  15. Migration of epoxidized soya bean oil from plasticized PVC gaskets into baby food.

    Science.gov (United States)

    Hammarling, L; Gustavsson, H; Svensson, K; Karlsson, S; Oskarsson, A

    1998-01-01

    Expoxidized soya bean oil (ESBO) is used as a plasticizer in PVC gaskets in lids for glass jars used for packaging of ready-cooked baby food. The migration of ESBO from the lids has been determined in 81 samples of different dishes of baby food, including purées of beef, pork, fish, poultry, berries and vegetables. The level of ESBO in baby food has been determined using a gas chromatography/mass spectrometry (GC/MS) analytical procedure with a detection limit of 1.5 mg/kg. Residues of ESBO were found in all dishes except in blueberries. The levels ranged from < 1.5 to 50.8 mg/kg, with a mean of 11.9 mg/kg and a median of 7.8 mg/kg in food with detectable levels. Expoxidized fatty acids may also occur naturally in food. Baby food which had never been in contact with the lids was therefore analysed and no detectable levels of diepoxidized C18-methylester, which was used for the determination of ESBO, were found. That demonstrates that the presented levels of ESBO in the baby food are only due to migration from the lids and not of natural origin. PMID:9602927

  16. Study of the hydro-mechanical behaviour of expanded graphite gaskets

    International Nuclear Information System (INIS)

    The poro-mechanical behaviour models developed by O. Coussy permit to consider various phenomena observed experimentally: thermo-hydro-mechanical couplings, plasticity, etc. The aim of this study is to implement the simplest poro-mechanical model (i.e. the isotropic linear poro-elastic model) to model the gasket hydro-mechanical behaviour. First, isotropic poro-elastic characteristics of expanded graphite have been estimated from these tests conducted at Departement Mecanique et Technologie des Composants (MTC) and data from literature. Then, analytical solutions of the tightness tests developed at the MTC Department have been carried out. These calculations provide a first estimation of porosity variations during a tightness tests with metal/metal contact or in elastic recovery, and during a 'hot thermal transient'. Thickness controlled numerical calculations have proved the analytical calculations relevance. With regard to simulation of tests with metal/metal contact or 'hot thermal transient', stress controlled numerical calculations have pointed out: - a greater vertical displacement on the inner side of the graphite ring and - a z dependence of the radial displacement and thus a porous differential variation between the upper and lower faces of the ring. (author)

  17. Effect of soft metal gasket contacts on contact resistance, energy deposition, and plasma expansion profile in a wire array Z pinch.

    Science.gov (United States)

    Gomez, M R; Zier, J C; Gilgenbach, R M; French, D M; Tang, W; Lau, Y Y

    2008-09-01

    Soft metal gaskets (indium and silver) were used to reduce contact resistance between the wire and the electrode in an aluminum wire Z pinch by more than an order of magnitude over the best weighted contact case. Clamping a gasket over a Z-pinch wire compresses the wire to the electrode with a greater normal force than possible with wire weights. Average contact resistance was reduced from the range of 100-3000 Omega (depending on wire weight mass) to 1-10 Omega with soft metal gaskets. Single wire experiments (13 microm Al 5056) on a 16 kA, 100 kV Marx bank showed an increase in light emission (97%) and emission volume (100%) of the plasma for the reduced contact resistance cases. The measured increases in plasma volume and light emission indicate greater energy deposition in the ablated wire. Additionally, dual-wire experiments showed plasma edge effects were significantly decreased in the soft metal gasket contact case. The average height of the edge effects was reduced by 51% and the width of the edge effects was increased by 40%, thus the gasket contact case provided greater axial uniformity in the plasma expansion profile of an individual wire. PMID:19044418

  18. Experimental and numerical study of damage initiation mechanism in elastomeric composites

    Directory of Open Access Journals (Sweden)

    T.D. Silva Botelho

    2009-09-01

    Full Text Available Purpose: Experimental and Finite Element Analysis (FEA of the damage initiation mechanisms in elastomeric composites were carried out under static loading at room temperature. Double Cantilever Beam (DCB specimens from natural rubber (NR vulcanised and reinforced with other materials such as carbon black, silica, fibres and textiles or metals (rubber composites.Design/methodology/approach: Very huge experimental results were compared with that of the Finite Element Analysis (FEA. Damage mechanism has been described with a threshold criterion to identify damage. The damage was evaluated just at the beginning of the tearing by assuming large strain. A typical type of specimen geometry of Double Cantilever Beam (DCB specimens was considered under static tensile tests conducted on the notched specimens with variable depths.Findings: In this stage of this research, a finite element analysis (FEA has been applied under the same conditions of this part in order to obtain the agreement between experimental and FEA results. The numerical modelling is a representation of a previous experimental study. The specimen is stretched more than once its initial size, so that large strains occur. A hyper elastic Moonley-Rivlin law and a Griffith criterion are chosen. The finite elements analysis was performed with ABAQUS code (V.6.4.4.Practical implications: A damage criterion was suggested in the case of simple tension conditions by assuming large strain levels. an effective finite elements model has been developed to evaluate notch size effects on the load-displacement elastic response of 3D-DCB type specimen.Originality/value: This study proposes a threshold criterion for the damage just at the beginning of the tearing for Double Cantilever Beam (DCB specimens from rubber composites and gives a detail discussion for explaining the damage mechanisms. Comparison of FEA results with those of experimental studies gives many facilities for the sake of simplicity in industrial applications.

  19. Force decay in orthodontic elastomeric chains after immersion in disinfection solutions

    Scientific Electronic Library Online (English)

    Karina Andréa Branco, Losito; Adriana Simoni, Lucato; Carlos Alberto Malanconi, Tubel; Cristian Alexandre, Correa; Julio Cesar Bentos dos, Santos.

    2014-12-01

    Full Text Available Aim: To evaluate the force decay of orthodontic elastomeric chains after immersion in disinfecting solutions. Methods: One-hundred and fifty segments of elastomeric chains were divided in 3 groups: Control group - no disinfection; Chlorhexidine group - disinfection in 0.12% chlorhexidine digluconate [...] solution; and Peracetic acid group - disinfection in 0.2% peracetic acid solution. Elastomeric chains of 14 mm were stretched up to 20 mm and the given force (kgf) was evaluated in an Instron universal testing machine at the following intervals: 1 h, 1 day, 7, 14, 21 and 28 days after the immersion in the disinfecting solutions. Data (kgf) were analyzed statistically by Analysis of Variance and Tukey's test at a 5% significance level. Results: Both groups presented similar force decay along 7 days and remained stable up to 28 days. Force degradation was observed in the first hours of activation (~50%). Conclusions: It may be concluded that there were no significant differences among the investigated groups, in most interval times, indicating that both chemical solutions can be used for previous disinfection of orthodontic elastomeric chains.

  20. Containment of fluid samples in the hydrothermal diamond-anvil cell without the use of metal gaskets: performance and advantages for in situ analysis.

    Science.gov (United States)

    Chou, I-Ming; Bassett, William A; Anderson, Alan J; Mayanovic, Robert A; Shang, Linbo

    2008-11-01

    Metal gaskets (Re, Ir, Inconel, or stainless steel) normally used to contain fluid samples in the hydrothermal diamond-anvil cell (HDAC) are sometimes undesirable due to possible contamination and to gasket deformation at high pressures and temperatures resulting in nonisochoric behavior. Furthermore, in x-ray spectroscopic experiments, metal gaskets may attenuate the incident x-ray beam and emitted fluorescence x-rays, and the interaction of scattered radiation with the gasket may produce fluorescence that interferes with the x-ray spectrum of the sample. New arrangements and procedures were tested for the operation of the HDAC without using the metal gaskets. Distilled, de-ionized water was loaded into the sample chamber, a laser-milled recess 300 microm in diameter and approximately 50 microm deep centered in the 1.0 mm face of the lower diamond anvil, and sealed by pressing the top diamond anvil face directly against the lower one without a metal gasket in between. A maximum sample pressure of 202 MPa at 617 degrees C was maintained for a duration of 10 min without evidence of leakage. A small change in fluid density was observed in one experiment where the sample was held at 266 MPa at 708 degrees C for 10 min. The gasketless HDAC was also employed in x-ray absorption spectroscopy experiments, where, in addition to the sample chamber in the lower diamond, two grooves were milled at a 90 degrees angle to each other around the sample chamber to minimize the attenuation of incident and fluorescent x rays. With a minimum distance between the sample chamber and the grooves of 80 microm, a pressure of 76 MPa at 500 degrees C was maintained for 2 h with no change in the original fluid density. PMID:19045909

  1. Novel elastomeric fibrous networks produced from poly(xylitol sebacate)2:5 by core/shell electrospinning: fabrication and mechanical properties.

    Science.gov (United States)

    Li, Yuan; Thouas, George A; Chen, Qizhi

    2014-12-01

    Fabrication of nonlinear elastic materials that resemble biological tissues remains a challenge in biomaterials research. Here, a new fabrication protocol to produce elastomeric fibrous scaffolds was established, using the core/shell electrospinning technique. A prepolymer of poly(xylitol sebacate) with a 2:5mol ratio of xylitol:sebacic acid (PXS2:5) was first formulated, then co-electrospun with polyvinyl alcohol (PVA - 95,000Mw). After cross-linking of core polymer PXS2:5, the PVA shells were rinsed off in water, leaving a porous elastomeric network of PXS2:5 fibres. Under aqueous conditions, the PXS2:5 fibrous scaffolds exhibited stable, nonlinear J-shaped stress-strain curves, with large average rupture elongation (76%) and Young?s modulus (~1.0MPa), which were in the range of muscle tissue. Rupture elongation of PXS2:5 was also much higher when electrospun, compared to 2D solid sheets (45%). In direct contact with cell monolayers under physiological conditions, PXS2:5 scaffolds were as biocompatible as those made of poly-l-lactic acid (PLLA), with improvements over culture medium alone. In conclusion, the newly developed porous PXS2:5 scaffolds show tissue-like mechanical properties and excellent biocompatibility, making them very promising for bioengineering of soft tissues and organs. PMID:25243671

  2. Seal performance of thermal aged metal gasket of dual purpose metal cask for interim spent fuel storage after external impact load

    International Nuclear Information System (INIS)

    As for interim storage for spent nuclear fuels using dual purpose dry metal cask in Japan, we recognize one of the important technical issues that there is a possibility for the cask with degraded metal gasket during storage to apply to transportation. In our study until 2003 focused on degradation of important components for the cask safety performance during storage and application to transportation, for metal gasket, we conducted property tests for degradation and influence of lid movement on seal performance, and furthermore verification tests. From the results, we developed the method to evaluate leak rate from lid with degraded metal gasket at accidents during transportation and in addition, we found as follows: Lid would hardly move and leak rate would not increase seriously during fire event. Leak rate from lid with degraded metal gasket could be evaluated by using results of leak rate trend depending on horizontal displacement of lid by external impact load. So, with regard to influence of lid movement on seal performance, we conducted additional test for extending horizontal displacement in lid moving in 2004. In addition, seal performance was discussed from the results, both previous and latest test. (authors)

  3. Increasing pumping efficiency in a micro throttle pump by enhancing displacement amplification in an elastomeric substrate

    International Nuclear Information System (INIS)

    Fluid transport is accomplished in a micro throttle pump (MTP) by alternating deformation of a micro channel cast into a polydimethylsiloxane (PDMS) elastomeric substrate. The active deformation is achieved using a bimorph PZT piezoelectric disc actuator bonded to a glass diaphragm. The bimorph PZT deflects the diaphragm as well as alternately pushing and pulling the elastomer layer providing displacement amplification in the PDMS directly surrounding the micro channel. In order to improve pumping rates we have embedded a polymethylmethacrylate (PMMA) ring into the PMDS substrate which increases the magnitude of the displacement amplification achieved. FEM simulation of the elastomeric substrate deformation predicts that the inclusion of the PMMA ring should increase the channel deformation. We experimentally demonstrate that inclusion of a PMMA ring, having a diameter equal to that of the circular node of the PZT/glass/PDMS composite, increases in the throttle resistance ratio by 40% and the maximum pumping rate by 90% compared to an MTP with no ring.

  4. Elastomeric negative acoustic contrast particles for capture, acoustophoretic transport, and confinement of cells in microfluidic systems.

    Science.gov (United States)

    Shields, C Wyatt; Johnson, Leah M; Gao, Lu; López, Gabriel P

    2014-04-15

    We present a particle-based method for the immunospecific capture and confinement of cells using acoustic radiation forces. Ultrasonic standing waves in microfluidic systems have previously been used for the continuous focusing of cells in rapid screening and sorting applications. In aqueous fluids, cells typically exhibit positive acoustic contrast and are thus forced toward the pressure nodes of a standing wave. Conversely, elastomeric particles exhibit negative acoustic contrast and travel toward the pressure antinodes. We have developed a class of elastomeric particles that are synthesized in bulk using a simple nucleation and growth process, providing precise control over their size and functional properties. We demonstrate that the biofunctionalization of these particles can allow the capture and transport of cells to the pressure antinodes solely via acoustic radiation forces, which may enable new acoustics-based cell handling techniques such as the washing, labeling, and sorting of cells with minimal preparatory steps. PMID:24673242

  5. Roll to plate printed stretchable silver electrode using single walled carbon nanotube on elastomeric substrate.

    Science.gov (United States)

    Jung, Minhun; Noh, Jinsoo; Kim, Junseok; Kim, Donghwan; Cho, Gyoujin

    2013-08-01

    Stretchable electronics may open new applications in display, sensors and actuators. To attain the stretchable electronics, the ink formulation should be compatible with elastomeric substrates. Here, we present the formulation of silver nanoparticles and single walled carbon nanotubes (SWNTs) for printing stretchable silver electrodes on the elastomeric substrates. Highly conductive stretchable electrodes can be printed directly on the poly(styrene-b-butadiene-b-styrene) (PSBS) substrates by roll to plate (R2P) gravure printer. During the stretching test, R2P printed silver based stretchable electrodes show the high conductivity of 1000 S cm(-1) at 0.27 wt% of SWNT loading. Furthermore, the resistance of the printed silver electrode was not changed up to 15% of tensile strain. PMID:23882805

  6. A simple scanning spectrometer based on a stretchable elastomeric reflective grating

    Energy Technology Data Exchange (ETDEWEB)

    Ghisleri, C.; Milani, P., E-mail: paolo.milani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano (Italy); WISE srl, Piazza Duse 2, 20122 Milano (Italy); Potenza, M. A. C.; Bellacicca, A. [CIMAINA and Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano (Italy); Ravagnan, L. [WISE srl, Piazza Duse 2, 20122 Milano (Italy)

    2014-02-10

    We report a scanning optical spectrometer based on the use of a stretchable elastomeric reflective grating. The grating is obtained by supersonic cluster beam implantation of silver nanoparticles on polydimethylsiloxane previously grooved by molding to create a replica of a commercial digital versatile disk grating. The use of a stretchable grating allows the spectrometer spanning the whole optical wavelength range by solely extending the diffraction element by more than 100% of its original dimensions. The stretchable reflective optical grating shows excellent performances and stability upon thousands of stretching cycles. The use of this elastomeric element makes the optical layout and the mechanics of the spectrometer extremely simple and advantageous for those applications where spectral resolution is not a major requirement. As a proof of principle, we present the absorption spectrum of Rhodamine B in solution obtained by our spectrometer and compared to commercial instruments.

  7. Microfluidic Automation using elastomeric valves and droplets: reducing reliance on external controllers

    OpenAIRE

    Kim, Sung-jin; Lai, David; Park, Joong Yull; Yokokawa, Ryuji; Takayama, Shuichi

    2012-01-01

    This paper gives an overview of elastomeric valve- and droplet-based microfluidic systems designed to minimize the need of external pressure to control fluid flow. This concept article introduces the working principle of representative components in these devices along with relevant biochemical applications. This is followed by providing a perspective on the roles of different microfluidic valves and systems through comparison of their similarities and differences with transistors (valves) an...

  8. Elastomeric impression as a diagnostic method of cavitation in proximal dentin caries in primary molars

    Scientific Electronic Library Online (English)

    Adriela Azevedo Souza, Mariath; Ana Eliza Lemes, Bressani; Fernando Borba de, Araujo.

    2007-12-01

    Full Text Available The purpose of this study was to validate the elastomeric impression after temporary tooth separation as a method of cavitation detection in proximal caries lesions in primary molars with outer half dentin radiolucency. Fifty-one children (4-10 years old), presenting radiolucency in the outer half o [...] f the dentin at the proximal surfaces of primary molars and proximal anatomic contact with the adjacent tooth (without restoration/cavitated caries lesion) were enrolled in the study. Temporary tooth separation was performed with an orthodontic rubber ring placed around the contact point during 2-3 days. Thereafter, impression of the proximal surfaces was made. The elastomeric impressions were classified as "non-cavitated" or "cavitated" surfaces. Visual inspection after tooth separation was considered as the gold standard. Examiner reliability of visual inspection after tooth separation was determined (kappa 0.92). Impression examination was repeated every 5 participants to evaluate the reproducibility of the method. The frequency of cavitated lesions was 65%, and 67% of those were inactive. Sensitivity, specificity, positive and negative predictive values were 0.88% (95%CI 0.73-0.95), 0.89% (95%CI 0.67-0.97), 0.94% (95%CI 0.79-0.98) and 0.80% (95%CI 0.58-0.92), respectively. Impression examination showed total agreement regarding cavitation. The evaluation of elastomeric impression after tooth separation is a useful clinical resource in cavitation detection for clinicians and researchers when visual inspection is doubtful.

  9. Evaluation of the influence of the polymer-filler interaction on compounds based on epoxidized elastomeric matrix and precipitated silica

    Scientific Electronic Library Online (English)

    Tatiana L. A. C., Rocha; Marly M., Jacobi; Dimitrios, Samios; Robert H., Schuster.

    2006-06-01

    Full Text Available The introduction of epoxy groups into the main chain of elastomers has emerged as a promising alternative, considering the monitoring of polymer-filler interaction leading to changes in the properties of vulcanizates. The epoxidation reaction (in situ) was chosen to modify elastomers, such as polybu [...] tadiene (BR) and copolymer of styrene-butadiene-rubber (SBR), because it is a simple, easily controlled reaction, even considering the small epoxidation degree. The modification degree of the polymeric chain was studied with FT-IR and ¹H-NMR. The shift of the Tg to high temperatures with the increase of the epoxy group in the polymer chain was monitored through differential scanning calorimetry (DSC). An analysis of the dynamic modulus of the material in relation to its dependence on the amplitude and temperature was carried out. The interaction between epoxidized elastomeric matrix and silica as filler was extremely improved, even in the presence of very low content of epoxy groups into the polymer chain.

  10. Evaluation of the influence of the polymer-filler interaction on compounds based on epoxidized elastomeric matrix and precipitated silica

    Directory of Open Access Journals (Sweden)

    Tatiana L. A. C. Rocha

    2006-06-01

    Full Text Available The introduction of epoxy groups into the main chain of elastomers has emerged as a promising alternative, considering the monitoring of polymer-filler interaction leading to changes in the properties of vulcanizates. The epoxidation reaction (in situ was chosen to modify elastomers, such as polybutadiene (BR and copolymer of styrene-butadiene-rubber (SBR, because it is a simple, easily controlled reaction, even considering the small epoxidation degree. The modification degree of the polymeric chain was studied with FT-IR and ¹H-NMR. The shift of the Tg to high temperatures with the increase of the epoxy group in the polymer chain was monitored through differential scanning calorimetry (DSC. An analysis of the dynamic modulus of the material in relation to its dependence on the amplitude and temperature was carried out. The interaction between epoxidized elastomeric matrix and silica as filler was extremely improved, even in the presence of very low content of epoxy groups into the polymer chain.

  11. Fracture mechanics and statistical mechanics of reinforced elastomeric blends

    CERN Document Server

    Heinrich, Gert; Kaliske, Michael; Klüppel, Manfred; Schneider, Konrad; Vilgis, Thomas

    2013-01-01

    Elastomers are found in many applications ranging from technology to daily life applications for example in tires, drive systems, sealings and print rollers. Dynamical operation conditions put extremely high demands on the performance and stability of these materials and their elastic and flow properties can be easily adjusted by simple manipulations on their elastic and viscous properties. However, the required service life suffers often from material damage as a result of wear processes such as abrasion and wear fatigue, mostly caused by crack formation and propagation. This book covers interdisciplinary research between physics, physical chemistry, material sciences and engineering of elastomers within the range from nanometres to millimetres and connects these aspects with the constitutive material properties. The different chapters describe reliable lifetime and durability predictions based on new fracture mechanical testing concepts and advanced material-theoretical methods which are finally implemented...

  12. Quantitative Evaluation of Dental Biofilm Accumulation in Elastomeric Ligatures in Relation to the Amount of Time Within the Oral Cavity

    Directory of Open Access Journals (Sweden)

    Hélida Neiva CAMPOS

    2006-04-01

    Full Text Available Objective: The aim of this study was to evaluate the amount of dental biofilm accumulation in the elastomeric ligatures of orthodontic patients, and compare the volume of biofilm on these ligatures after one, two, three and four weeks of use. Method: Twenty patients with permanent dentition were selected from the Clinic of Orthodontics of the UFJF. No specific instructions regarding oral hygiene were given to these patients. After prophilaxis, only the four second premolars of each patient in the sample received the same type of elastomeric ligatures. All ligatures were individually stored in a Petri plaque, prepared and numbered. Each plaque received one ligature and was weighed in an analytic scale up to two hours before its insertion into the oral cavity. The elastomeric ligatures were removed from the second premolars after one, two, three and four weeks respectively. The ANOVA and the Student's “t” test were applied (P< 0.05. Results: The results showed a weekly and progressive increase in weight of the elastomeric ligatures, being the second week the least relevant. It could be verified that the difference between the initial and final weights was statistically significant. Conclusion: The elastomeric ligatures can accumulate a considerable amount of dental biofilm which tends to increase with time.

  13. Structure and Mechanical Properties of Elastomeric Block Copolymers

    Science.gov (United States)

    Alfonzo, Carlos Guillermo

    This research presents the synthesis (by anionic polymerization and catalytic hydrogenation) and characterization of two types of block copolymers: CMC and XPX. In CMC, C is glassy poly(cyclohexylethylene) and M, the matrix, can be semicrystalline poly(ethylene) E, rubbery poly(ethylene-alt-propylene) P, or rubbery poly(ethylethylene) EE, or a combination to yield: CPC, CEEC, CEC, CPEEC and CEPC, with volume fraction fC = 0.18 -- 0.30. XPX materials have X = CEC, fC = fE, and fPP = 0.40 -- 0.60. Block copolymer phase behavior and morphology were examined through a combination of DSC, rheology, SAXS, WAXS and TEM. CMC materials are melt-ordered due to block thermodynamic incompatibility with TODT > Tg(C) = 147 °C and show lamellar or C cylinder morphologies. The design of XPX yields melt disordered materials up to high Mn with microphase segregation induced by E crystallization. Two high Mn XPX polymers are melt ordered above Tm(E) and show two correlation lengths in SAXS assigned to the C -- E and X -- P length scales. TEM images indicate that all XPX materials, irrespective of melt segregation, are characterized by composite glassy and crystalline hard domains dispersed in rubbery P at room temperature. Tensile and recovery testing at room temperature show that CMC and XPX materials, with the exception of plastic CEC, behave as thermoplastic elastomers with tunable properties. Interestingly, melt disordered XPX materials have competitive mechanical properties comparable to the strongest CMC polymers, but with advantageous processing. For melt ordered CMC, Tprocess > TODT, which is dependent on Mn, while for melt disordered XPX, Tprocess > Tm(E) = 100 °C independent of M n. The deformation of melt disordered XPX materials, probed by recovery studies and WAXS, suggests that deformation is first taken by P, then E and finally C, which causes ultimate failure. This implies that strain recovery in XPX materials can be comparable to that of CPC if materials contain low hard block content or are stretched to strains below the onset of E deformation. Finally, a collection of data of mechanical properties, namely modulus, strain at break, tensile strength and tension set, obtained from CMC, XPX and previously reported materials were examined. Most notably, modulus and tension set were found to be strongly correlated with the volume fractions of C and E, as properties increase with (fC + fE) alpha, where alpha = 1 -- 2.4. Ultimate properties such as tensile strength and strain at break are unaffected by changes in composition as failure is dictated by that of the hard domains and values are similar above a minimum amount of hard block. In addition, modulus, tensile strength and strain at break are inversely correlated to rubber entanglement molecular weight Me, which implies that modulus and ultimate properties are affected by the ability of the rubber network to redistribute stress by entanglement slippage. However, tension set is unresponsive to Me variations, which indicates that irrecoverable deformation in these materials results from deformation of the hard domains.

  14. Phase diagram and exotic spin-spin correlations of J$_1$-J$_2$ Ising model on the Sierpi\\'nski gasket

    OpenAIRE

    Ran, Shi-Ju; LIU, TAO; Zhao, Yang; Su, Gang

    2013-01-01

    The J$_1$-J$_2$ antiferromagnetic Ising model on the fractal Sierpi\\'nski gasket is intensively studied, and a number of exotic properties are disclosed. The ground state phase diagram in the plane of magnetic field-interaction of the system is obtained, where three nontrivial phases including the $1/3$ magnetization plateau ordered and disordered phases, and the $5/9$ plateau partially ordered phase, as well as five boundaries and two intersection points are accurately iden...

  15. Study on the properties of damping bitumen material

    International Nuclear Information System (INIS)

    The damping mechanisms of visco-elastomeric materials under the vibration are described, and the dynamic mechanical properties of damping bitumen material are studied.The experimental results show that the kind of raw materials, temperature and vibrational frequency have great influence on the loss factors of damping bitumen materials and that the plasticizers contributed to the range of damping temperature. The shear motion and the internal dissipation of materials increased by adding the planar filler, such as graphites, are also indicated

  16. Baseline and Lifetime Assessments for DC745U Elastomeric Components

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, R S; Chinn, S C; Herberg, J; Harvey, C; Alviso, C; Vance, A; Cohenour, R; Wilson, M; Solyom, D

    2004-12-20

    The silicone elastomer Dow Corning DC 745U is used in two major components in the W80. We have investigated a number of issues concerning this material. Our studies have accomplished a baseline study of the chemical composition of DC745 and LLNL now has a good understanding of the chemical composition of this material. DC745 crystallizes within the system STS. Two potential means identified to mitigate the risk associated with this phenomenon are to (1) change material formulation and (2) predose the parts to {approx} 25 MRad {gamma}-radiation. A candidate material identified by Gordon Spellman has been studied for composition and the lack of crystallization within the STS has been verified. A sensitivity study of the effects of relevant aging mechanisms also has been performed. The extent of aging due to radiation exposure or elevated temperatures is minimal over the expected course of the LEP. In addition, since the DC745 parts are expected to be replaced at rebuild, the aging clock is essentially being reset. No significant aging issues seem likely to develop for these parts. DC745 parts are also subject to permanent deformation in service. Our studies have shown that the deformation is likely due to incomplete mixing of the raw gum stock and the curing agent at production. This results in areas of low crosslink density that are subject to a higher degree of compression set in service. We have identified two production diagnostic tools based on Nuclear Magnetic Resonance spectroscopy to prescreen the parts at production at KCP. These studies are concluded with specific recommendation for changes to core surveillance for this part based on the chemical knowledge we have gained from this study.

  17. A practical model for lifetime prediction of elastomeric seals in nuclear environments

    International Nuclear Information System (INIS)

    A lifetime prediction model for elastomeric seals in nuclear environments has been developed, based on the principle of time-temperature-dose rate superposition. The earlier empirical model has been simplified and put on a more rigorous mathematical basis, enabling predictions to be made of the behavior of seals at the low dose rates normally seen in service. The model can account for both dose rate effects and synergy between temperature and radiation. Some examples of the practical use of the modified model are given

  18. TN trademark FLEX: a new generation of fluorocarbon o-rings developed by COGEMA logistics with enhanced characteristics at low temperature (-40 C)

    International Nuclear Information System (INIS)

    Three main types of elastomers are used for the sealing of radioactive material transport casks with elastomeric gaskets: EPDM, fluorocarbons type Viton registered (standard designation: FKM) and silicon rubbers. Each rubber has specific characteristics in terms of temperature range, permeability, coefficient of expansion.. For the casks where high temperatures can be reached (200 C in continuous using), FKM gaskets are generally used. The problem is that this type of gasket does not guarantee the leaktightness at -40 C, which is a regulatory requirement. Two solutions are generally used: to specify a minimum heat load or a minimum ambient temperature. The direct consequence is that it is impossible to get B(U) approvals on the new concepts when FKM gaskets are used but only B(M) approvals, which generate significant additional justification costs (multiple submittals of Safety Analysis Reports, calculation of the minimum heat load or of the minimum ambient temperature..). Thus, it is important to develop gaskets with the same performance as FKM gaskets at high temperature but with enhanced performance at low temperature (and mainly, which guarantee the leaktightness at -40 C). COGEMA LOGISTICS has qualified a new generation of fluorocarbon O-rings (TN trademark FLEX gaskets) which can be used in continuous service on a -47 C/+200 C temperature range. TN trademark FLEX gaskets will be implemented on new casks designs

  19. Towards development of lignin reinforced elastomeric compounds with reduced energy dissipation

    Science.gov (United States)

    Bahl, Kushal

    This research deals with development of lignin as reinforcing filler for elastomeric compounds. Lignins are naturally abundant and cost competitive wood derivatives possessing strong mechanical properties and offering reactive functional groups on their surfaces. The presence of the functional groups imparts polarity to the lignin molecules and makes them incompatible with non-polar elastomers. Also, the large particle size of lignin does not produce desired mechanical reinforcement. The present study deals with solving the outstanding issues associated with the use of lignin as fillers for polymeric compounds. In addition, the work specifically focuses on producing rubber compounds with reduced energy dissipation via partial replacement of carbon black with lignin. The first part of this study is devoted to suppression of the polarity of lignin and achievement of compatibility with rubber matrix via modification of lignosulfonates (LS) with cyclohexylamine (CA). CA reduces the polarity of lignin via interactions originating from proton transfer and hydrogen bonding. X-ray Photoelectron Spectroscopy (XPS) confirms the attachment of CA on the surfaces of lignin. The mechanical properties of rubber compounds increase substantially along with improvement in cure properties and increase in crosslink density in the presence of LS particles modified with CA. The tensile strength and storage modulus show an increase by 45% and 41% respectively. The values of the 100% modulus and elongation at break also improve by 35% and 60% respectively. The second part of this study exploits the non-covalent interactions between lignin and carbon black (CB) for the design of novel hybrid filler particles exhibiting lower energy loss in rubber compounds. The hybrid fillers offer unique morphology consisting of coating layers of lignin on carbon black particle aggregates. It is found that such coating layers are formed due to pi-pi interactions between lignin and carbon black. Raman spectroscopy and 1H spin-lattice relaxation times confirm pi-pi interactions. The hybrid fillers offer reduction of networking of carbon black particles and viscoelastic dissipation in rubber compounds without sacrificing the mechanical performance. The third part of this study evaluates the performance of polybutadiene- g-polypentafluorostyrene (PB-g-PPFS) as a coupling agent for promotion of interactions between lignin and rubber and to achieve better overall reinforcing performance. The PB domains of PB-g-PPFS are compatible with styrene-butadiene rubber (SBR) while the PPFS segments engage in arene-perfluoroarene interactions with lignin. These interactions are confirmed via UV-vis spectroscopy data. The efficacy of PB-g-PPFS as a coupling agent is evaluated for compounds filled with lignin and lignin/carbon black hybrid fillers. The results show that the addition of PB-g-PPFS improves the tensile strength by 33% and reduces the viscoelastic loss in filled SBR compounds by improving filler dispersion. The results presented in this thesis demonstrate that the approaches of surface modification, exploitation of non-covalent interactions, and the use of coupling agents are effective in solving the impending issues associated with the use of lignin, the second most abundant bio-derived material, as effective reinforcing filler for polymer compounds.

  20. Assessmentof seismic stability of buildings that have seismicprotection in the form of elastomeric isolators ?????? ??????????????? ?????? ? ????????????? ? ???? ??????????????????? ????

    Directory of Open Access Journals (Sweden)

    Mkrtychev Oleg Vartanovich

    2013-08-01

    Full Text Available Nowadays, various systems of seismic protection are applied to assure seismic protection of buildings and structures, located in earthquake areas. The greatest prevalence and popularity has been attained by the systems of active seismic protection.In this article, the authors study the efficiency of application of an active seismic protection system by taking high-damping rubber elastomeric isolators as an example. Calculations and their comparative analysis were made for a high-rise reinforced concrete building, and their exposure to the seismic impact was examined. Those calculations were made both with and without the application of the active seismic isolation system. Calculations were carried out by means of the linearly-spectral method using Lira software. Maximum relative horizontal moments arising on the top of the building and forces applied to the elements of walls and columns were compared. On the basis of the results of the calculations and their comparative analysis, the conclusion is drawn that elastomeric isolators may be efficiently applied as an active seismic protection system.???????? ??????? ?????????? ????????? ?????? ???????? ????????????, ? ?.?. ??????????????????? ????? (???, ??? ?????? ?? ????????????? ?????? ? ??????????, ????????????? ? ??????????? ??????? ???????. ?????????? ???????-???????????? ?????? ??????????????? ?????? ? ??????????? ??????? ???????? ?????????????? ? ???? ??? ? ??? ??? ? ??????????? ????????? «????». ?????????? ????????????? ?????? ??????????? ???????.

  1. Effect of elastomeric ligatures on frictional forces between the archwire and orthodontic bracket

    Scientific Electronic Library Online (English)

    Flávia Ramos, Venâncio; Sílvia Amélia Scudeler, Vedovello; Carlos Alberto Malanconi, Tubel; Viviane Veroni, Degan; Adriana Simone, Lucato; Letícia Nery, Lealdim.

    2013-03-01

    Full Text Available AIM: To evaluate the frictional force between the archwire and orthodontic bracket generated by elastomeric ligatures with polymer coating (Super slick, TP Orthodontics) and conventional ligatures (Morelli) using two types of insertion techniques. METHODS: Forty elastomeric ligatures, 20 with polyme [...] r coating and 20 conventional, were evaluated. Each type of ligature was separated into two groups (n=10), according to the insertion mode: conventional or crossed (from mesial to distal region crossed in front). To analyze friction, 40 5-cm-long segments of stainless steel orthodontic archwire 0.019" x 0.025" (Morelli) and Edgewise brackets (slot 0.022" x 0.028"; Morelli) were used. Each set (bracket, wire and elastic) was submitted to frictional testing in a universal test machine (Instron 4411) at a crosshead speed of 5 mm/min. Each bracket was moved 5 mm on the wire, with maximum friction and mean friction being recorded by software. Three readouts were taken for each bracket. Data were submitted to two-way ANOVA and Tukey's test (p

  2. A highly sensitive and flexible pressure sensor with electrodes and elastomeric interlayer containing silver nanowires.

    Science.gov (United States)

    Wang, Jun; Jiu, Jinting; Nogi, Masaya; Sugahara, Tohru; Nagao, Shijo; Koga, Hirotaka; He, Peng; Suganuma, Katsuaki

    2015-02-21

    The next-generation application of pressure sensors is gradually being extended to include electronic artificial skin (e-skin), wearable devices, humanoid robotics and smart prosthetics. In these advanced applications, high sensing capability is an essential feature for high performance. Although surface patterning treatments and some special elastomeric interlayers have been applied to improve sensitivity, the process is complex and this inevitably raises the cost and is an obstacle to large-scale production. In the present study a simple printing process without complex patterning has been used for constructing the sensor, and an interlayer is employed comprising elastomeric composites filled with silver nanowires. By increasing the relative permittivity, ?r, of the composite interlayer induced by compression at high nanowire concentration, it has been possible to achieve a maximum sensitivity of 5.54 kPa(-1). The improvement in sensitivity did not sacrifice or undermine the other features of the sensor. Thanks to the silver nanowire electrodes, the sensor is flexible and stable after 200 cycles at a bending radius of 2 mm, and exhibits outstanding reproducibility without hysteresis under similar pressure pulses. The sensor has been readily integrated onto an adhesive bandage and has been successful in detecting human movements. In addition to measuring pressure in direct contact, non-contact pressures such as air flow can also be detected. PMID:25588044

  3. Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres

    Science.gov (United States)

    Park, Minwoo; Im, Jungkyun; Shin, Minkwan; Min, Yuho; Park, Jaeyoon; Cho, Heesook; Park, Soojin; Shim, Mun-Bo; Jeon, Sanghun; Chung, Dae-Young; Bae, Jihyun; Park, Jongjin; Jeong, Unyong; Kim, Kinam

    2012-12-01

    Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (? ~ 2,200 S cm-1 at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.

  4. Geothermal Elastomeric Materials Technology-Transfer (GEM-TT) Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hirasuna, A.R.; Friese, G.J.; Stephens, C.A.

    1982-12-01

    The primary objective, to promote broad use of the earlier developed elastomers technology appears to have been successfully accomplished. The expertise was transferred to three rubber products manufacturers, and is currently commercially available. Significant substantiation of the viability of the technology was fostered through supporting and tracking numerous test efforts in various industry laboratories and out in the field. Numerous papers were presented on the technology and information was also disseminated verbally and by providing data packages. The formal and informal technology transfer effort are described. Several secondary spin-offs also resulted. Steps toward a better understanding of the complex technology transfer process were achieved. The experience provides a data point illustrating one way that technology transfer can be accomplished and a data point which can be used to evaluate its effectiveness. And finally studies were made assessing the potential of elastomers to perform at even higher temperatures.

  5. Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres.

    Science.gov (United States)

    Park, Minwoo; Im, Jungkyun; Shin, Minkwan; Min, Yuho; Park, Jaeyoon; Cho, Heesook; Park, Soojin; Shim, Mun-Bo; Jeon, Sanghun; Chung, Dae-Young; Bae, Jihyun; Park, Jongjin; Jeong, Unyong; Kim, Kinam

    2012-12-01

    Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (? ? 2,200 S cm(-1) at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications. PMID:23178335

  6. Development of high-temperature joints for thermochemical hydrogen production by IS process. Applicability examination of the coned-disk springs assembly and seal performance test of candidate gaskets

    International Nuclear Information System (INIS)

    Thermo-chemical Iodine-Sulfur (IS) process can produce large amount of hydrogen effectively without emission of greenhouse effect gas such as carbon dioxide, where nuclear thermal energy of a high temperature gas-cooled reactor (HTGR) is adopted as a heat source. The IS process uses strong acids such as sulfuric acid and hydriodic acid in high temperature and pressure conditions. Therefore, it is necessary to develop large-size chemical reactors featuring materials that exhibit high temperature and corrosion resistance. A SO3 decomposer, which is one of key components of the IS process, consists of a pressure vessel for high temperature and high pressure helium gas and an internal structure for SO3 decomposition by the latent heat of the helium gas. Since joints of the internal structure will be heated up to 700degC, we designed a high-temperature joint coupled with coned-disk springs and SiC bolts (coned-disk springs assembly) so as to keep seal performance under high temperature condition. This report presents applicability examination results of designed coned-disk springs assembly as well as seal performance test results of candidate gaskets. (author)

  7. Correlation of elastomer material properties from small specimen tests and scale-size bearing tests

    International Nuclear Information System (INIS)

    Tests were performed on small-size elastomer specimens and scale-size laminated elastomeric bearings to correlate the material properties in shear between the two types of tests. An objective of the tests was to see how well the material properties that were determined from specimen tests could predict the response of scale-size laminated elastomeric bearings. Another objective was to compare the results of specimen test and scale-size bearing test conducted by different testing organizations. A comparison between the test results from different organizations on small specimens showed very good agreement. In contrast, the correlation of scale-size bearing tests showed differences in bearing stiffness

  8. Caracterisation de l'effet du vieillissement en milieu aqueux sur les proprietes mecaniques de composites a matrice elastomere

    Science.gov (United States)

    Favre, Audrey

    Rubber composites are widely used in several engineering fields, such as automotive, and more recently for inflatable dams and other innovative underwater applications. These rubber materials are composed by an elastomeric matrix while the reinforcing phase is a synthetic fabric. Since these components are expected to operate several years in water environment, their durability must be guaranteed. The use of rubber materials immersed in water is not new, in fact, these materials have been studied for almost one century. However, the knowledge on reinforced rubber composites immersed several years in water is still limited. In this work, investigations on reinforced rubbers were carried out in the framework of a research project in partnership with Alstom and Hydro-Quebec. The objective of this study was to identify rubber composites that could be used under water for long periods. Various rubber composites with ethylene-propylene-diene monomer (EPDM), silicone, EPDM/silicone and polychloroprene (Neoprene) matrices reinforced with E-glass fabric were studied. Thus, these materials were exposed to an accelerated ageing at 85 °C underwater for periods varying from 14 to 365 days. For comparison purposes, they were also immersed and aged one year at room temperature (21 °C). The impact of accelerated aging was estimated through three different characterization methods. Scanning electron microscopy (SEM) was first used to assess the quality of fiber-matrix interface. Then, water absorption tests were performed to quantify the rate of water absorption during immersion. Finally the evolution of the mechanical properties was followed by the determination of Young's modulus (E) and ultimate stress (sigmau) using a dedicated traction test. This analysis allowed to point out that the quality of the fiber-matrix interface was the main factor influencing the drop of the mechanical properties and their durability. Moreover, it was noticed that this interface could be improved by using appropriate coupling agent as confirmed by the silicone composite with treated fabric. It was also observed that fiber-matrix interface could be a place where high stresses were localized because of differential swelling leading to an important loss of mechanical properties. The results revealed very different behaviors from one composite to another. The accelerated aging of EPDM/silicone and Neoprene composites led to a rapid diminution of mechanical properties in only 14 days. Conversely, silicone composites showed a 20 % increase of mechanical properties after 75 days of immersion. EPDM composites exhibited an important variability from one sample to another. It can be concluded from this study that composites made from silicone matrix with treated E-glass result in a better durability underwater. Keywords: composite elastomer, accelerated ageing, immersion in the water

  9. Comparison of frictional resistance between self-ligating and conventional brackets tied with elastomeric and metal ligature in orthodontic archwires

    Scientific Electronic Library Online (English)

    Vanessa Vieira, Leite; Murilo Baena, Lopes; Alcides, Gonini Júnior; Marcio Rodrigues de, Almeida; Sandra Kiss, Moura; Renato Rodrigues de, Almeida.

    2014-06-01

    Full Text Available OBJETIVO: comparar a resistência ao atrito entre braquetes autoligáveis e braquetes convencionais, variando o tipo de fio. MÉTODOS: foram usados braquetes incisivos Abzil Kirium Capelozza e Easy Clip. Uma ligadura elastomérica ou um fio ligável de 0,010" foi usado para ligação do fio no braque [...] te Abzil. Três tipos de ligas de fio ortodôntico foram avaliadas: fio de NiTi de 0,016"; fio de NiTi de 0,016" x 0,022"; e fio de aço de 0,019" x 0,025". Dez observações foram feitas para cada combinação "braquete-fio-inclinação". Os braquetes foram montados em um aparelho especial, posicionados a 90° em relação ao fio, e testados em duas inclinações. O teste de atrito foi realizado na máquina universal de ensaios, a 5mm/min e com 10mm de deslocamento. As médias (em MPa) foram submetidas aos testes ANOVA e de Tukey, a 5% de significância. As superfícies dos fios e dos braquetes foram observadas no MEV. RESULTADOS: o braquete com amarrilhos metálicos (16,48 ± 8,31MPa) apresentou médias mais altas que o braquete com ligaduras elastoméricas (4,29 ± 2,16MPa) e o braquete autoligável (1,66 ± 1,57) (p 0,05). Nenhuma diferença estatística (p > 0,05) foi encontrada entre inclinações de zero (7,76 ± 8,46) e cinco (7,19 ± 7,93) graus. Concluão: o atrito foi influenciado pelo tipo de braquete e sistemas de ligaduras. Diferentes aspectos morfológicos foram observados para os braquetes e fios estudados. Abstract in english OBJECTIVE: To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. MATERIAL AND METHODS : Abzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a ligating wire 0. [...] 10-in was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were assessed: 0.016-in NiTi wire, 0.016 x 0.021-in NiTi wire and 0.019 x 0.025-in steel wire. Ten observations were carried out for each bracket-archwire angulation combination. Brackets were mounted in a special appliance, positioned at 90 degrees in relation to the wire and tested in two angulations. Frictional test was performed in a Universal Testing Machine at 5 mm/min and 10 mm of displacement. The means (MPa) were submitted to ANOVA and Tukey's test set at 5% of significance. The surfaces of wires and brackets were observed at SEM. RESULTS: Steel-tied brackets (16.48 ± 8.31) showed higher means of frictional resistance than elastomeric-tied brackets (4.29 ± 2.16 ) and self-ligating brackets (1.66 ± 1.57) (P 0.05). No statistical differences (P > 0.05) were found between zero (7.76 ± 8.46) and five-degree (7.19 ± 7.93) angulations. CONCLUSIONS: Friction was influenced not only by the type of bracket, but also by the ligating systems. Different morphological aspects were observed for the brackets and wires studied

  10. The use of dual material seals for packaging

    International Nuclear Information System (INIS)

    The use of dual material seals, metal and elastomeric for a transportation package, provides a viable option for packages requiring high temperature seal capability. Allowing the seal area to go to higher temperatures then allowed for all elastomeric seal reduce the necessity of providing thermal protection during a postulated accident condition fire. It also increases the options for impact limiting features that do not also mitigate the affects of accident thermal events. Typically, high temperature seals require the use of metal O-rings. Only one seal (typically identified as the containment seal) needs to survive the hypothetical accident conditions, including the high temperatures that may occur during the prescribed hypothetical thermal event. However, to expedite the assembly leakage rate testing of radioactive material packages, a dual O-ring seal arrangement is often used to allow creation of a relatively small volume test cavity between the seals. For any package that is being used on a frequent basis, the total cost of seals can be significantly reduced by using an elastomeric seal as the secondary seal. The elastomeric seal is not the containment boundary seal and does not need to survive the high temperature condition. To get the dual material O-ring seals to seat properly, a different approach has to be taken than with closure of a radioactive material package that does not use metallic O-ring(s). A metal O-ring requires an application of a seating force while the elastomeric package requires a certain percentage of deformation. This is further complicated when the seating force is developed using a multi-bolt closure. Because of the nature of multi-bolt closures, elastic interaction prevents the equal application of force. This paper develops the methods involved in properly closing and establishing containment when using dual material seals with a multi-bolt closure. These methods were demonstrated in two production casks requiring testing leak rates of 10-7 standard cc/sec

  11. The Redistribution of Load in Bolted Gasketed Joints Subjected to Steady State Thermal Loading

    International Nuclear Information System (INIS)

    Pressure vessel joints operating at high temperature are often very difficult to seal. The existing flange design methods do not address thermal effects other than the variation of flange material mechanical properties with temperature. It is possible to include the effects of temperature loading in joint analysis, however, presently very few guidelines exist for this type of analysis. This paper outlines the theoretical analysis used for the determination of the steady state operating temperature and the induced loads in flange joints. It details the theoretical equations necessary to predict the temperature and the redistribution of load due to the thermal expansion of the joint components for the case of a pair flange and the case of a flange with a blind-cover. The results from the theoretical models are verified by comparison to finite element results. (authors)

  12. Compilation of current literature on seals, closures, and leakage for radioactive material packagings

    International Nuclear Information System (INIS)

    This report presents an overview of the features that affect the sealing capability of radioactive material packagings currently certified by the US Nuclear Regulatory Commission. The report is based on a review of current literature on seals, closures, and leakage for radioactive material packagings. Federal regulations that relate to the sealing capability of radioactive material packagings, as well as basic equations for leakage calculations and some of the available leakage test procedures are presented. The factors which affect the sealing capability of a closure, including the properties of the sealing surfaces, the gasket material, the closure method and the contents are discussed in qualitative terms. Information on the general properties of both elastomer and metal gasket materials and some specific designs are presented. A summary of the seal material, closure method, and leakage tests for currently certified packagings with large diameter seals is provided. 18 figs., 9 tabs

  13. Compilation of current literature on seals, closures, and leakage for radioactive material packagings

    Energy Technology Data Exchange (ETDEWEB)

    Warrant, M.M.; Ottinger, C.A.

    1989-01-01

    This report presents an overview of the features that affect the sealing capability of radioactive material packagings currently certified by the US Nuclear Regulatory Commission. The report is based on a review of current literature on seals, closures, and leakage for radioactive material packagings. Federal regulations that relate to the sealing capability of radioactive material packagings, as well as basic equations for leakage calculations and some of the available leakage test procedures are presented. The factors which affect the sealing capability of a closure, including the properties of the sealing surfaces, the gasket material, the closure method and the contents are discussed in qualitative terms. Information on the general properties of both elastomer and metal gasket materials and some specific designs are presented. A summary of the seal material, closure method, and leakage tests for currently certified packagings with large diameter seals is provided. 18 figs., 9 tabs.

  14. Modification of PVC compounds with butadiene-acrylonitrile elastomers

    Directory of Open Access Journals (Sweden)

    J. Stabik

    2006-04-01

    Full Text Available Purpose: The purpose of the paper is to present the research programme on influence of acrylonitrile-butadiene copolymers on properties of plasticized polyvinylchloride as window gaskets material.Design/methodology/approach: Short literature review concerning application of modified PVC as gasket material was presented. In experimental part two types of acrylonitrile-butadiene copolymers were used as elastomeric plasticizers. Compounds with fifteen different levels of modifiers content (up to 25% by weight were prepared and tested. Additionally three commercial compounds were tested as reference formulations. The following test were performed: Shore hardness, short-term and long-term elastic recovery, tensile strength, elongation at break and migration of plasticizers from gasket material to unplasticized PVC.Findings: Application of acrylonitrile-butadiene copolymers as PVC modifier enhanced many properties essential for window gasket materials such as long-term and short term elastic recovery, tensile strength and elongation at break. At the same time addition of these elastomers did not change migration of other plasticizers contained in gasket material. Obtained results indicated that among tested compounds best properties as gasket material exhibited plasticized PVC with 23% of acrylonitrile-butadiene copolymer Chemigum P83. Reference commercial compounds exhibited worse performance properties than compounds with this acrylonitrile-butadiene copolymer. Practical implications: Research programme allowed to elaborate plasticized PVC compounds modified with acrylonitrile-butadiene copolymer that can be industrially applied for PVC window gaskets.Originality/value: Obtained results are of scientific and practical value. Research programme allowed to investigate the influence of elastomeric modifiers on plasticized PVC properties. Research results are also of practical importance.

  15. Non-linear analysis of a closure manway using spiral wound gasket with metal-metal contact and a new geometry approach

    International Nuclear Information System (INIS)

    The results of a PWR pressurizer closure manway analysis are presented. The manway geometry is slightly different from the conventional solution with the goal to reduce the bending stresses in the bolts when the system is pressurized. So the salt stresses value will also be reduced. The viability of the proposed solution will be confirmed by: verification of the stresses in the bolts connecting the blind flange to the nozzle by ASME III, subsection NB and level of the tightness reached in the spiral wound (type SG) gasket based in the criteria defined in the references. (author)

  16. Mechanics of nanowire buckling on elastomeric substrates with consideration of surface stress effects

    Science.gov (United States)

    Gao, Fei; Cheng, Qian; Luo, Jun

    2014-11-01

    In this paper, the surface stress effects are considered in the analysis of nanowire buckling on elastomeric substrates. Theoretical solutions of the buckling wavenumber, amplitude, and the critical strain for the out-of-surface buckling are derived firstly. After that, the influences of the surface properties, size, bulk modulus, and the shape of the cross section of the nanowire on the out-of-surface and in-surface buckling behavior are systematically discussed. Our study indicates that the buckling mode of the nanowire can be greatly influenced by the surface effects. For nanowires with small cross section sizes and low bulk modulus, the buckling mode may be varied by tuning the surface properties. Based on the energy criterion, we explicitly determine the range of the parameters where the two buckling modes take place.

  17. Mechanics of nanowire/nanotube in-surface buckling on elastomeric substrates

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, J; Huang, Y [Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208 (United States); Ryu, S Y; Paik, U [Division of Materials Science and Engineering, Hanyang University, 17 Hangdang-dong, Sungdong-gu, Seoul 133-791 (Korea, Republic of); Hwang, K-C [Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Rogers, J A, E-mail: y-huang@northwestern.edu, E-mail: jrogers@uiuc.edu [Department of Materials Science and Engineering, Frederick-Seitz Materials Research Laboratory and Beckman Institute, University of Illinois at Urbana-Champaign, Illinois 61801 (United States)

    2010-02-26

    A continuum mechanics theory is established for the in-surface buckling of one-dimensional nanomaterials on compliant substrates, such as silicon nanowires on elastomeric substrates observed in experiments. Simple analytical expressions are obtained for the buckling wavelength, amplitude and critical buckling strain in terms of the bending and tension stiffness of the nanomaterial and the substrate elastic properties. The analysis is applied to silicon nanowires, single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanotube bundles. For silicon nanowires, the measured buckling wavelength gives Young's modulus to be 140 GPa, which agrees well with the prior experimental studies. It is shown that the energy for in-surface buckling is lower than that for normal (out-of-surface) buckling, and is therefore energetically favorable.

  18. Buckling of an elastic rod embedded on an elastomeric matrix: planar vs. non-planar configurations.

    Science.gov (United States)

    Su, Tianxiang; Liu, Jia; Terwagne, Denis; Reis, Pedro M; Bertoldi, Katia

    2014-09-01

    We investigate the buckling of a slender rod embedded in a soft elastomeric matrix through a combination of experiments, numerics and theory. Depending on the control parameters, both planar wavy (2D) or non-planar coiled (3D) configurations are observed in the post-buckling regime. Our analytical and numerical results indicate that the rod buckles into 2D configurations when the compression forces associated to the two lowest critical modes are well separated. In contrast, 3D coiled configurations occur when the two buckling modes are triggered at onset, nearly simultaneously. We show that the separation between these two lowest critical forces can be controlled by tuning the ratio between the stiffness of the matrix and the bending stiffness of the rod, thereby allowing for specific buckling configurations to be target by design. PMID:25029186

  19. Mechanics of nanowire/nanotube in-surface buckling on elastomeric substrates

    International Nuclear Information System (INIS)

    A continuum mechanics theory is established for the in-surface buckling of one-dimensional nanomaterials on compliant substrates, such as silicon nanowires on elastomeric substrates observed in experiments. Simple analytical expressions are obtained for the buckling wavelength, amplitude and critical buckling strain in terms of the bending and tension stiffness of the nanomaterial and the substrate elastic properties. The analysis is applied to silicon nanowires, single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanotube bundles. For silicon nanowires, the measured buckling wavelength gives Young's modulus to be 140 GPa, which agrees well with the prior experimental studies. It is shown that the energy for in-surface buckling is lower than that for normal (out-of-surface) buckling, and is therefore energetically favorable.

  20. A highly sensitive and flexible pressure sensor with electrodes and elastomeric interlayer containing silver nanowires

    Science.gov (United States)

    Wang, Jun; Jiu, Jinting; Nogi, Masaya; Sugahara, Tohru; Nagao, Shijo; Koga, Hirotaka; He, Peng; Suganuma, Katsuaki

    2015-02-01

    The next-generation application of pressure sensors is gradually being extended to include electronic artificial skin (e-skin), wearable devices, humanoid robotics and smart prosthetics. In these advanced applications, high sensing capability is an essential feature for high performance. Although surface patterning treatments and some special elastomeric interlayers have been applied to improve sensitivity, the process is complex and this inevitably raises the cost and is an obstacle to large-scale production. In the present study a simple printing process without complex patterning has been used for constructing the sensor, and an interlayer is employed comprising elastomeric composites filled with silver nanowires. By increasing the relative permittivity, ?r, of the composite interlayer induced by compression at high nanowire concentration, it has been possible to achieve a maximum sensitivity of 5.54 kPa-1. The improvement in sensitivity did not sacrifice or undermine the other features of the sensor. Thanks to the silver nanowire electrodes, the sensor is flexible and stable after 200 cycles at a bending radius of 2 mm, and exhibits outstanding reproducibility without hysteresis under similar pressure pulses. The sensor has been readily integrated onto an adhesive bandage and has been successful in detecting human movements. In addition to measuring pressure in direct contact, non-contact pressures such as air flow can also be detected.The next-generation application of pressure sensors is gradually being extended to include electronic artificial skin (e-skin), wearable devices, humanoid robotics and smart prosthetics. In these advanced applications, high sensing capability is an essential feature for high performance. Although surface patterning treatments and some special elastomeric interlayers have been applied to improve sensitivity, the process is complex and this inevitably raises the cost and is an obstacle to large-scale production. In the present study a simple printing process without complex patterning has been used for constructing the sensor, and an interlayer is employed comprising elastomeric composites filled with silver nanowires. By increasing the relative permittivity, ?r, of the composite interlayer induced by compression at high nanowire concentration, it has been possible to achieve a maximum sensitivity of 5.54 kPa-1. The improvement in sensitivity did not sacrifice or undermine the other features of the sensor. Thanks to the silver nanowire electrodes, the sensor is flexible and stable after 200 cycles at a bending radius of 2 mm, and exhibits outstanding reproducibility without hysteresis under similar pressure pulses. The sensor has been readily integrated onto an adhesive bandage and has been successful in detecting human movements. In addition to measuring pressure in direct contact, non-contact pressures such as air flow can also be detected. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06494a

  1. Thermomechanical analysis of thin films on temperature-dependent elastomeric substrates in flexible heterogeneous electronics

    International Nuclear Information System (INIS)

    Thermomechanical analysis is presented to study the basic temperature effects on elastomeric substrate of flexible electronics. Strains of a films-on-substrate structure related with three key temperatures are given based on the interfacial continuum model. An improved strain model is given and compared with other two models. The role of the temperature-dependent effects is highlighted and adopted to design a flexible inorganic/organic heterogeneous structure subject to little thermal action. The sensitivity analysis of three key temperatures is investigated, by which proper selection of technological parameter for poly(dimethylsiloxane) fabrication may be determined to eliminate the variation of stress of the interface in circumstances with temperature varying severely. This work contributes to systemic reliability and compatibility, structural design and thermal management of flexible electronics.

  2. Elastomeric 2D Grating and Hemispherical Optofluidic Chamber for Multifunctional Fluidic Sensing

    CERN Document Server

    Xu, Zhida

    2014-01-01

    We present an optofluidic sensor based on an elastomeric two-dimensional (2D) grating integrated inside a hemispherical fluid chamber. Laser beam is diffracted before (reflection) and after (transmission) going through the grating and liquid in the dome chamber. The sensing mechanism is investigated and simulated with a finite difference time domain (FDTD) based electromagnetic (EM) method. For experiment, by analyzing the size, power and shape of the 2D diffraction patterns, we can retrieve multiple parameters of the liquid including the refractive index, pressure and opacity with high sensitivity. We demonstrate that glucose concentration can be monitored when mixed in different concentrated phosphate buffered saline (PBS) solution. The free-solution binding of bovine serum albumin (BSA) and anti-BSA IgG is detected with this optical sensor. This low-cost, multifunctional and reliable optofluidic sensor has the potential to be used as monitor of biofluid such as blood in hemodialysis.

  3. Highly elastomeric poly(glycerol sebacate)-co-poly(ethylene glycol) amphiphilic block copolymers.

    Science.gov (United States)

    Patel, Alpesh; Gaharwar, Akhilesh K; Iviglia, Giorgio; Zhang, Hongbin; Mukundan, Shilpaa; Mihaila, Silvia M; Demarchi, Danilo; Khademhosseini, Ali

    2013-05-01

    Poly(glycerol sebacate) (PGS), a tough elastomer, has been proposed for tissue engineering applications due to its desired mechanical properties, biocompatibility and controlled degradation. Despite interesting physical and chemical properties, PGS shows limited water uptake capacity (?2%), thus constraining its utility for soft tissue engineering. Therefore, a modification of PGS that would mimic the water uptake and water retention characteristics of natural extracellular matrix is beneficial for enhancing its utility for biomedical applications. Here, we report the synthesis and characterization of highly elastomeric poly(glycerol sebacate)-co-polyethylene glycol (PGS-co-PEG) block copolymers with controlled water uptake characteristics. By tailoring the water uptake property, it is possible to engineer scaffolds with customized degradation and mechanical properties. The addition of PEG results in almost 15-fold increase in water uptake capacity of PGS, and improves its mechanical stability under dynamic loading conditions. PGS-co-PEG polymers show elastomeric properties and can be subjected to serve deformation such as bending and stretching. The Young's modulus of PGS-co-PEG can be tuned from 13 kPa to 2.2 MPa by altering the amount of PEG within the copolymer network. Compared to PGS, more than six-fold increase in elongation was observed upon PEG incorporation. In addition, the rate of degradation increases with an increase in PEG concentration, indicating that degradation rate of PGS can be regulated. PGS-co-PEG polymers also support cell proliferation, and thus can be used for a range of tissue engineering applications. PMID:23453201

  4. Evaluation of the susceptibility to pigmentation of orthodontic esthetic elastomeric ligatures

    Scientific Electronic Library Online (English)

    Janine Soares, Cavalcante; Marcelo de Castellucci e, Barbosa; Marcio Costa, Sobral.

    2013-04-01

    Full Text Available OBJETIVO: avaliar alterações da pigmentação de ligaduras elásticas estéticas após imersão em solução de pigmentação. MÉTODOS: Sessenta ligaduras foram selecionadas e divididas em doze grupos de acordo com a marca comercial utilizada e nas condições normal e distendida. Os grupos foram divididos em: [...] Morelli transparente, TP Orthodontics transparente, American Orthodontics transparente, Unitek/3M transparente, American Orthodontics pérola e Unitek/3M pérola, separados quanto à condição normal e distendida, totalizando 5 ligaduras em cada condição. A avaliação das mudanças de coloração foi realizada por meio de fotografia digital e análise computadorizada usando o programa Adobe Photoshop. Foram realizadas fotografias digitais padronizadas nos tempos T0 - antes do processo de pigmentação, com as ligaduras em estado normal; e T1 - após o processo de pigmentação, que durou cinco dias. A solução de pigmentação utilizada foi composta por saliva artificial e por alimentos que possuem potencial de coloração. No tempo T1, as ligaduras se encontravam em estado distendido e em estado normal (sem distensão). RESULTADO: os resultados do presente estudo demonstraram que ligaduras elásticas estéticas são suscetíveis à pigmentação. Dentre as marcas comerciais avaliadas a TP Orthodontics e American Orthodontics transparente foram as mais estáveis. Já a Unitek/3M pérola demonstrou alterações estatisticamente significativas em todas as variáveis avaliadas. CONCLUSÃO: ligaduras elásticas estéticas são suscetíveis à pigmentação, não havendo diferença estatisticamente significativa entre o estado normal e o estado distendido, com exceção na marca TP Orthodontics. A marca Unitek/3M pérola demonstrou ser a que apresenta maior potencial para pigmentação. Abstract in english OBJECTIVE: The purpose of this laboratory study was to evaluate changes in the pigmentation of esthetic elastomeric ligatures after immersion in a staining solution. METHODS: Sixty ligatures were selected and divided into 12 groups according to their brand and also considering their condition, i.e., [...] unstretched or stretched. The groups were divided into: Morelli (clear), TP Orthodontics (clear), American Orthodontics (clear), 3M/Unitek (clear), American Orthodontics (pearl color) and 3M/Unitek (pearl color), separated into groups of 5 unstretched and five stretched ligatures. Assessment of their color changes was performed by means of digital photograph and computer analysis using Adobe Photoshop. Standardized digital photographs were taken at T0 (before the staining process, with unstretched ligatures) and at T1 (following the 5-days staining process). The staining solution was composed of artificial saliva and foods with staining potential. At T1 the ligatures were either stretched or unstretched. RESULTS: The results of this study showed that esthetic elastomeric ligatures are prone to staining. Among the evaluated brands, TP Orthodontics and American Orthodontics clear ligatures were the most stable. Moreover, 3M/Unitek pearl ligatures demonstrated statistically significant changes in all variables. CONCLUSIONS: Esthetic elastomeric ligatures are susceptible to staining and no statistically significant difference was found between unstretched or stretched ligatures, with the sole exception of the TP Orthodontics brand. The 3M/Unitek's pearl color ligatures displayed the greatest staining potential.

  5. Static characterization of a soft elastomeric capacitor for non destructive evaluation applications

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, Hussam [Civil, Construction and Environmental Engineering, Iowa State University (United States); Laflamme, Simon [Civil, Construction and Environmental Engineering, Iowa State University and Electrical and Computer Engineering, Iowa State University (United States); Zhang, Huanhuan; Geiger, Randall [Electrical and Computer Engineering, Iowa State University (United States); Kessler, Michael; Rajan, Krishna [Materials Science and Engineering, Iowa State University (United States)

    2014-02-18

    A large and flexible strain transducer consisting of a soft elastomeric capacitor (SEC) has been proposed by the authors. Arranged in a network setup, the sensing strategy offers tremendous potential at conducting non-destructive evaluation of large-scale surfaces. In prior work, the authors have demonstrated the performance of the sensor at tracking strain history, localizing cracks, and detecting vibration signatures. In this paper, we characterize the static performance of the proposed SEC. The characterization includes sensitivity of the signal, and temperature and humidity dependences. Tests are conducted on a simply supported aluminum beam subjected to bending as well as on a free standing sensor. The performance of the SEC is compared against off-the-shelf resistance-based strain gauges with resolution of 1 ??. A sensitivity of 1190 pF/? is obtained experimentally, in agreement with theory. Results also show the sensor linearity over the given level of strain, showing the promise of the SEC at monitoring of surface strain.

  6. Static characterization of a soft elastomeric capacitor for non destructive evaluation applications

    International Nuclear Information System (INIS)

    A large and flexible strain transducer consisting of a soft elastomeric capacitor (SEC) has been proposed by the authors. Arranged in a network setup, the sensing strategy offers tremendous potential at conducting non-destructive evaluation of large-scale surfaces. In prior work, the authors have demonstrated the performance of the sensor at tracking strain history, localizing cracks, and detecting vibration signatures. In this paper, we characterize the static performance of the proposed SEC. The characterization includes sensitivity of the signal, and temperature and humidity dependences. Tests are conducted on a simply supported aluminum beam subjected to bending as well as on a free standing sensor. The performance of the SEC is compared against off-the-shelf resistance-based strain gauges with resolution of 1 ??. A sensitivity of 1190 pF/? is obtained experimentally, in agreement with theory. Results also show the sensor linearity over the given level of strain, showing the promise of the SEC at monitoring of surface strain

  7. Parallel near-field photolithography with metal-coated elastomeric masks.

    Science.gov (United States)

    Wu, Jin; Yu, Cheng-han; Li, Shaozhou; Zou, Binghua; Liu, Yayuan; Zhu, Xiaoqun; Guo, Yuanyuan; Xu, Hongbo; Zhang, Weina; Zhang, Liping; Liu, Bin; Tian, Danbi; Huang, Wei; Sheetz, Michael P; Huo, Fengwei

    2015-01-27

    Developing a cost-effective nanolithography strategy that enables the production of subwavelength features with various shapes over large areas is a long-standing goal in the nanotechnology community. Herein, an inexpensive nanolithographic technique that combines the wafer-scale production capability of photolithography with the subwavelength feature size controllability of near-field photolithography was developed to fabricate centimeter-scale up to wafer-scale sub-100-nm variously shaped nanopatterns on surfaces. The wafer-scale elastomeric trench-based photomasks with subwavelength apertures created at the apexes were compatible with mask aligners, allowing for the production of wafer-scale subwavelength nanopatterns with adjustable feature sizes, shapes, and periodicities. The smallest feature sizes of 50 and 80 nm were achieved on positive tone and negative tone photoresist surfaces, respectively, which could be ascribed to a near-field optical effect. The fabricated centimeter-scale nanopatterns were functionalized to study cell-matrix adhesion and migration. Compared to currently developed nanolithographic methods that approach similar functionalities, this facile nanolithographic strategy combines the merits of low cost, subwavelength feature size, high throughput, and varied feature shapes, making it an affordable approach to be used in academic research for researchers at most institutions. PMID:25549246

  8. Patterning the Stiffness of Elastomeric Nanocomposites by Magnetophoretic Control of Cross-linking Impeder Distribution

    Directory of Open Access Journals (Sweden)

    Suvojit Ghosh

    2015-01-01

    Full Text Available We report a novel method to pattern the stiffness of an elastomeric nanocomposite by selectively impeding the cross-linking reactions at desired locations while curing. This is accomplished by using a magnetic field to enforce a desired concentration distribution of colloidal magnetite nanoparticles (MNPs in the liquid precursor of polydimethysiloxane (PDMS elastomer. MNPs impede the cross-linking of PDMS; when they are dispersed in liquid PDMS, the cured elastomer exhibits lower stiffness in portions containing a higher nanoparticle concentration. Consequently, a desired stiffness pattern is produced by selecting the required magnetic field distribution a priori. Up to 200% variation in the reduced modulus is observed over a 2 mm length, and gradients of up to 12.6 MPa·mm?1 are obtained. This is a significant improvement over conventional nanocomposite systems where only small unidirectional variations can be achieved by varying nanoparticle concentration. The method has promising prospects in additive manufacturing; it can be integrated with existing systems thereby adding the capability to produce microscale heterogeneities in mechanical properties.

  9. An investigation on low-velocity impact response of elastomeric & crushable foams

    Science.gov (United States)

    Sadighi, Mojtaba; Salami, Sattar

    2012-12-01

    The mechanical behavior of elastomeric foam, in particular, Ethylene Propylene Diene Methyle (EPDM) and crushable foams, in particular, Expanded Poly-Propylene (EPP) and Poly Urthane Rigid (PUR), under low-velocity impact are studied experimentally and numerically. At first, these foams were loaded under quasi-static loading in compression. In order to study the dependence of their behavior on strain rate, the loadings were performed in two rates, 3 mm/min and 100 mm/min. The low-velocity impact tests were applied using a drop hammer testing machine. The drop heights of projectile in all tests were 0.5 and 1 m. The thickness effect of specimens on absorption of energy and parameters such as, contact force and displacement of specimens are discussed. Then, the dynamic factors of force and energy for three types of foam are investigated. Since, EPP showed an insensitive property to the thickness of specimen in the impact tests, it is possible to define dynamic factors for different thickness of this type of foam. Finally, all test results are compared with numerical results through implementation of ABAQUS finite element package. Good agreements between numerical results and experimental data show the capability of numerical modeling to fulfill the experimental investigation.

  10. Mechanics and optics of stretchable elastomeric microlens array for artificial compound eye camera

    Science.gov (United States)

    Li, Zhengwei; Xiao, Jianliang

    2015-01-01

    Compound eye-inspired imaging devices can find vast applications due to their remarkable imaging characteristics, such as extremely large field of view angle, low aberrations, high acuity to motion, and infinite depth of field. Recently, researchers have successfully developed a digital camera that resembles the structure and functions of apposition compound eyes of arthropod, by combining an elastic array of microlenses with a stretchable array of photodetectors in their planar form and then transforming into a hemispherical shape. Designing an elastomeric microlens array that can be mechanically stretched to very large extent without deteriorating the optical performance is critical to this development. In this study, mechanics and optics of the stretchable microlens array, in which each hemispherical microlens sits on top of a supporting post connected to a base membrane, are studied. The results show that proper designs of the microlenses, supporting posts and base membrane are critically important to meet both mechanical and optical requirements simultaneously. This study can have important implications in not only the design of artificial compound eye cameras, but also other developments that require stretchable optical elements.

  11. Probing Mechanoregulation of Neuronal Differentiation by Plasma Lithography Patterned Elastomeric Substrates

    Science.gov (United States)

    Nam, Ki-Hwan; Jamilpour, Nima; Mfoumou, Etienne; Wang, Fei-Yue; Zhang, Donna D.; Wong, Pak Kin

    2014-11-01

    Cells sense and interpret mechanical cues, including cell-cell and cell-substrate interactions, in the microenvironment to collectively regulate various physiological functions. Understanding the influences of these mechanical factors on cell behavior is critical for fundamental cell biology and for the development of novel strategies in regenerative medicine. Here, we demonstrate plasma lithography patterning on elastomeric substrates for elucidating the influences of mechanical cues on neuronal differentiation and neuritogenesis. The neuroblastoma cells form neuronal spheres on plasma-treated regions, which geometrically confine the cells over two weeks. The elastic modulus of the elastomer is controlled simultaneously by the crosslinker concentration. The cell-substrate mechanical interactions are also investigated by controlling the size of neuronal spheres with different cell seeding densities. These physical cues are shown to modulate with the formation of focal adhesions, neurite outgrowth, and the morphology of neuroblastoma. By systematic adjustment of these cues, along with computational biomechanical analysis, we demonstrate the interrelated mechanoregulatory effects of substrate elasticity and cell size. Taken together, our results reveal that the neuronal differentiation and neuritogenesis of neuroblastoma cells are collectively regulated via the cell-substrate mechanical interactions.

  12. Elastomeric Nanocomposite Foams for the Removal of Heavy Metal Ions from Water.

    Science.gov (United States)

    Chavan, Asmita A; Li, Hongbo; Scarpellini, Alice; Marras, Sergio; Manna, Liberato; Athanassiou, Athanassia; Fragouli, Despina

    2015-07-15

    We report the fabrication and utilization of elastomeric polymer nanocomposite foams for the efficient removal of Pb(2+) and Hg(2+) heavy metal ions from polluted water. The polydimethylsiloxane (PDMS) foams are properly modified in order to become hydrophilic and allow the polluted water to penetrate in their volume. The ZnSe colloidal nanocrystals (NCs) that decorate the surface of the foams, act as active components able to entrap the metal ions. In this way, after the dipping of the nanocomposite foams in water polluted with Pb(2+) or Hg(2+), a cation exchange reaction takes place, and the heavy metal ions are successfully removed. The removal capacity for the Pb(2+) ions exceeds 98% and the removal of Hg(2+) ions approaches almost 100% in the studied concentrations region of 20-40 ppm. The reaction is concluded after 24 h, but it should be noticed that after the first hour, more than 95% of both the metal ions is removed. The color of the foams changes upon heavy metal ions entrapment, providing thus the opportunity of an easy detection of the presence of the ions in water. Taking into account that the fabricated foams provide good elastic properties and resistance to heat, they can be used in different conditions of water remediation. PMID:26133912

  13. On the mobility of iron particles embedded in elastomeric silicone matrix

    International Nuclear Information System (INIS)

    In this contribution the rheological and magnetorheological properties of different polydimethylsiloxane (PDMS) based magnetorheological elastomers (MRE) are presented and discussed. In order to investigate the mobility of the iron particles with respect to the rheological characteristics, the iron particles were silanized with vinyltrimethoxysilane to enable a reaction between the modified particle and the cross-linking agent of the silicone elastomer. In addition, the vinyl-functionalized particles were further modified by the coupling of the superficial vinyl groups with a long-chain hydride terminated PDMS, which enables a reaction pathway with the vinyl terminated PDMS. On the other hand, the iron particles were treated with surfactants such as fatty acids, calcium and aluminum soaps, respectively, prior to vulcanization in order to increase the mobility of the iron particles in the elastomeric matrix. It was found, that both, the modification with the long-chain hydride terminated PDMS as well as the treatment with surfactants lead to an increase of the storage modulus G', the loss modulus G'' and the loss factor tan ? in the magnetic field. It is concluded that both modifications, the coupling with long-chain hydride terminated PDMS as well as the treatment with surfactants, provide a greater mobility of the iron particles and hence a greater friction represented by the increase of the loss factor tan ?. Consequently it is assumed that untreated iron particle is assumed that untreated iron particles are less mobile in the rubber matrix due to covalent bonding with the silicone components, most likely due to the reaction of the hydroxyl groups on the metal surface with the silane groups of the cross-linking agent.

  14. On the mobility of iron particles embedded in elastomeric silicone matrix

    Science.gov (United States)

    Rabindranath, R.; Böse, H.

    2013-02-01

    In this contribution the rheological and magnetorheological properties of different polydimethylsiloxane (PDMS) based magnetorheological elastomers (MRE) are presented and discussed. In order to investigate the mobility of the iron particles with respect to the rheological characteristics, the iron particles were silanized with vinyltrimethoxysilane to enable a reaction between the modified particle and the cross-linking agent of the silicone elastomer. In addition, the vinyl-functionalized particles were further modified by the coupling of the superficial vinyl groups with a long-chain hydride terminated PDMS, which enables a reaction pathway with the vinyl terminated PDMS. On the other hand, the iron particles were treated with surfactants such as fatty acids, calcium and aluminum soaps, respectively, prior to vulcanization in order to increase the mobility of the iron particles in the elastomeric matrix. It was found, that both, the modification with the long-chain hydride terminated PDMS as well as the treatment with surfactants lead to an increase of the storage modulus G', the loss modulus G" and the loss factor tan ? in the magnetic field. It is concluded that both modifications, the coupling with long-chain hydride terminated PDMS as well as the treatment with surfactants, provide a greater mobility of the iron particles and hence a greater friction represented by the increase of the loss factor tan ?. Consequently it is assumed that untreated iron particles are less mobile in the rubber matrix due to covalent bonding with the silicone components, most likely due to the reaction of the hydroxyl groups on the metal surface with the silane groups of the cross-linking agent.

  15. Elastomeric matrix composites: effect of processing conditions on the physical, mechanical and viscoelastic properties

    Directory of Open Access Journals (Sweden)

    D. Zaimova

    2012-02-01

    Full Text Available Purpose: The aim of this study is to investigate the influence of accelerator-vulcanizing agent system and the vulcanization temperature on the properties of vulcanizates based on Natural rubber/Polybutadiene rubber (NR/BR compounds. This preliminary study will allow optimizing the composition for improving the mechanical properties and understanding the damage behaviour.Design/methodology/approach: NR/BR based composites with different vulcanization temperatures and curing systems were characterized in respect of their curing characteristics (for 140ºC and 160ºC and mechanical properties. The cure characteristics of the rubber compounds were studied by using the Monsanto MDR 2000 rheometer. The mechanical properties were investigated- tensile strength, elongation at break, tensile modulus at 100% (M100 and at 300% (M300 deformation. The hardness (Shore A and molecular mass of the samples were also determined. Scanning electron microscopy was used to study the microstructure of the fracture surfaces.Findings: The processing, physical, mechanical and viscoelastic properties and chemical structure of the mixture of Natural rubber/Polybutadiene rubber (NR/BR compounds have been evaluated in detail for the compounds of D1 and D2 (140/160.Research limitations/implications: limitations/implications: Some critical point, control of the temperature during vulcanization in press, can introduce some restrictions; these measurements can play on the final vulcanizates and in the course of processing.Practical implications: In practical way, mechanical test results (tensile and shore A give very useful information about the damage behaviour of the elastomeric matrix composites.Originality/value: Natural rubber/Polybutadiene rubber (NR/BR compounds were mixed by additions of some certain elements to improve physical, mechanical and viscoelastic properties and damage behaviours of these compounds produced under certain conditions.

  16. Study on domestic material purchasing in MSR manufacture of conventional island

    International Nuclear Information System (INIS)

    Combining the real case of Dongfang Electric (Guangzhou) Heavy Machinery Co., Ltd. trying to purchase the domestic sealing gasket as needed in the MSR of the conventional island, this paper describes the trends and relevant experience about nuclear power equipment manufacturers purchasing materials in the domestic market, and provides a reference to broadening the procurement channels of the purchasing departments of nuclear equipment manufacturers. (author)

  17. Case files of the University of Massachusetts Fellowship in Medical Toxicology: Lethal dose of opioids contained in an elastomeric capsule labeled as vancomycin

    OpenAIRE

    Courtney, James M.; Boyer, Edward W.

    2008-01-01

    This case describes the adulteration of a vancomycin elastomeric capsule with opioids that likely arose from degradation of heroin [29–31]. Although the clinical management of patients suffering the effects of contaminated drugs may be straightforward, the public health risk associated with adulterated pharmaceuticals and drug delivery devices should mandate a brisk response from governmental regulatory agencies.

  18. Development of bus body rubber profiles with additives from renewable sources: Part I – Additives characterization and processing and cure properties of elastomeric compositions

    International Nuclear Information System (INIS)

    Highlights: • Bus body rubber profiles with additives from renewable sources. • Soybean oil, vulcanization activator from ethanol production and cereal loading filler. • Physical, chemical and thermal characterization of the additives. • Processing and cure properties of elastomeric compositions. • Components commonly used by the rubber industry can be replaced by these additives. - Abstract: The goal of this work was to characterize additives from renewable sources aiming replace the components that are traditionally used by the rubber industry in a formulation with terpolymer of ethylene–propylene–diene (EPDM). Soybean oil (MD600®) was used as a plasticizer. The vulcanization activator (MDECR®) was a sub-product from cellulosic ethanol production, while the loading filler (MDCO®) was obtained from cereals. Firstly, the physical, chemical and thermal properties of these additives were investigated. Thus, a standard composition used for bus body rubber profiles and compositions containing varying proportions of these additives were prepared. The acceleration system was added in a laboratory two-roll mill after the elastomeric compositions were processed in a torque rheometer. The elastomeric compositions were characterized by their cure properties, Mooney viscosities, differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The addition of these additives led to a decrease in the viscosity, work, energy and Mooney viscosity of each composition, thus improving its processability. The curing characteristics of elastomeric compositions were affected by the addition of MD600® and MDECR®, leading to lower vulcanization time, while the cure properties were not affected by the addition of MDCO®

  19. Low-cost encapsulation materials for terrestrial solar cell modules

    Science.gov (United States)

    Cuddihy, E. F.; Baum, B.; Willis, P.

    1979-01-01

    The paper presents the findings of material surveys intended to identify low cost materials which could be functional as encapsulants (by 1986) for terrestrial solar cell modules. Economic analyses have indicated that in order to meet the low cost goal of $2.70 per sq m, some or all of the following material technologies must be developed or advanced: (1) UV screening outer covers; (2) elastomeric acrylics; (3) weatherproofing and waterproofing of structural wood and paper products; (4) transparent UV stabilizers for the UV-sensitive transparent pottants; and (5) cost-effective utilization of silicone and fluorocarbon materials.

  20. Materials

    Science.gov (United States)

    Glaessgen, Edward H.; Schoeppner, Gregory A.

    2006-01-01

    NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

  1. From 1 ? 3 dendritic designs to fractal supramacromolecular constructs: understanding the pathway to the Sierpi?ski gasket.

    Science.gov (United States)

    Newkome, George R; Moorefield, Charles N

    2014-10-15

    The iterative synthetic protocols used for dendrimer construction were developed based on the desire to easily craft highly branched macromolecules with ideally an exact mass and tailored functionality. Inspired by arboreal design and precursors of the utilitarian macromolecules known as dendrimers today, our first examples employed predesigned, 1 ? 3 or 1 ? (1 + 2) C-branched, building blocks. Physical characteristics of the dendrimers, including their globular shapes, excellent solubility, and demonstrated aggregation, revealed the inherent supramolecular potential. The architecture that is characteristic of dendritic materials also exhibits obvious fractal qualities based on self-similar, repetitive, branched frameworks. Thus, both the fractal design and supramolecular aspects of these constructs are suggestive of a larger field of fractal materials that incorporate repeating geometries and are derived by complementary building block recognition and assembly. Use of terpyridine-M(2+)-terpyridine connectivity for the sides and tuned directed organic vertices has opened the door to other types of novel materials. This approach also circumvents the nonideality of dendrimers, since the heteroleptic, one-step, spontaneous self-assembly process facilitates quantitative outcomes. PMID:25316287

  2. Analytical investigations on elastomeric shells of new Poly Implant Prothèse (PIP) breast and from sixteen cases of surgical explantation.

    Science.gov (United States)

    Beretta, Giangiacomo; Panseri, Sara; Manzo, Alessandra; Hamid, Rufaida; Richards, Adrian; Malacco, Matteo

    2014-09-01

    In this study we have analysed the chemical composition of the extractable components from the elastomeric shells from n=27 explanted implants (n=16 patients), n=2 new PIP implants, and from explanted Eurosilicone and McGhan implants (n=2 for each brand). Empty elastomeric PIP shells (n=2) were also available for analysis. Prostheses were explanted between 2011 and 2012, after 3-11 years of implantation. Patients presented pre- and post-operation complications of different degrees. First we evaluated the micro-structural features of the shells by phase contrast microscopy, and compared the results with those obtained using attenuated total reflectance infrared spectroscopy (ATR-FT-IR), head space gas chromatography coupled to mass spectrometry (HS-GC-MS) and GC-MS in direct injection mode. The results of these studies confirm and explain the conclusion of previous international investigations that evidenced a linear decrease of rupture rate for prostheses implanted after 2006. The analytical identification of a series of UV sensitive radical photo-initiators (0.1%-0.2% w/w), belonging to the benzophenone family, in the shells of new and explanted prostheses produced after 2006 (associated with a strong smell absent in those produced earlier), in parallel to (ii) the removal of the anti bleed barrier from their manufacturing procedure (introduced after 2001), strongly suggested that from 2007, the PIP company used a polymerisation process different from that declared, probably as a consequence of the first reports of rupture problems. In addition, the HS-GC-MS experiments demonstrated that at body temperature the diffusivity of low molecular weight (LMW) silicones present in the PIP filler silicone is significantly higher than that of LMW silicones in an approved implant. PMID:24915531

  3. Experimental water vapor permeability results for common wall materials

    Energy Technology Data Exchange (ETDEWEB)

    Sipes, J.M.; Hosni, M.H.

    2000-07-01

    This paper presents the experimental water vapor permeability results for gypsum board, latex paint, permeable vinyl wallpaper, vinyl wallpaper, and elastomeric stucco. For each material, a series of modified cup tests was conducted, and the material water vapor permeability was obtained as a function of relative humidity across the specimen. This test method was a modification of the ASTM Standard Test Method E 96-93. The permeability values for the materials tested in this study were compared to the limited available data from literature and were found to be in good agreement.

  4. Remifentalino intravenoso mediante infusor elastomerico frente a meperidina intramuscular: Estudio comparativo en analgesia obstetrica Intravenous remifentanil delivered through an elastomeric device versus intramuscular meperidine comparative study for obstetric analgesia

    Directory of Open Access Journals (Sweden)

    E. Calderón

    2006-10-01

    Full Text Available Objetivos: Evaluar la eficacia y seguridad de remifentanilo administrado mediante infusor elastomérico con PCA iv en analgesia obstétrica comparado con meperidina intramuscular en parturientas con contraindicación para analgesia epidural. Material y Método: Se seleccionaron aletoriamente 24 parturientas, se asoció infusor elastomérico Baxter® con 250 ml de suero fisiológico con 2,5 mg de remifentanilo y un ritmo de 12 ml·h ¹, lo que supone una infusión media de 0,025 ?g·kg-1·min-1 de remifentanilo, permitiendo la administración de bolos de 5 ml con un tiempo de cierre de 30 minutos (Grupo R o 1 mg·kg¹ de meperidina y 2,5 mg de haloperidol (Grupo M vía intramuscular cada 4 h. Valoramos la intensidad del dolor cada 30 min mediante una escala analógica visual (EVA, tiempo de infusión, bolos administrados, el nivel de sedación mediante escala del estado de alerta y sedación evaluada por el observador (OAA/S, efectos adversos y el test de Apgar del recién nacido al minuto y a los 5 min. Resultados: No hubo diferencias en los datos antropométricos de ambos grupos. La duración media de la infusión en el grupo R fue de 280 ± 55 min y las necesidades de bolos de rescate de 1,2 ± 1,5. La dosis media de meperidina intramuscular en el grupo M fue de 120 ± 25 mg. La intensidad del dolor durante el parto fue significativamente menor en el grupo R durante todo el periodo de dilatación y expulsivo (pObjectives: To evaluate the effectiveness and security of remifentanil administered by means of elastomeric infusor with PCA IV compared obstetrical analgesia with intramuscular meperidine in obstetric patients with contraindication for epidural analgesia, Material and Method: 24 patients were randomized, an elastomeric infusor Baxter® with a capacity of 250 ml was filled with 2.5 mg of remifentanil and a 12 mililiter·h-1, was satarted, (average infusion of 0.025·kg-1·min-1 of remifentanil, and boluses of 5 ml with a time of closing of 30 minutes (Group R or 1 mg/kg-1 of meperidine and 2.5 mg of haloperidol (Group M every 4 h by IM route. We valued the intensity of pain each 30 min by means of a visual analogical scale (EVA, time of infusion, boluses administered, level of sedatión by means of scale of the alert status and sedatión evaluated by observer (OAA/S, adverse effects and the Apgar test of new born to 1 and 5 min. Results: There were no differences in the anthropometric data of both groups. The average duration of the infusion in group R was of 280 ± 55 min and the necessities of boluses of 1.2 rescue of ± 1,5. The average dose of intramuscular meperidine in group M was of 120 ± 25 mg. The intensity of the pain during the childbirth was significantly smaller in group R (p<0,05 that group M. The sedatión level was similar in both groups (OAA/S 1-2. The hemodinámics parameters, cardiac rate and arterial pressure remained stable without significant differences between both groups. There was no case of respiratory depression. The satisfaction degree was significantly superior in group R. Conclusion: Remifentanil administered by means of elastomeric system PCA IV provides an analgesic effectiveness superior to the intramuscular meperidine and constitutes an alternative modality to the epidural analgesia without causing respiratory depression or excessive sedation, with an elevated level of maternal satisfaction.

  5. Materials for vacuum seals and dielectric breaks in near term and commercial reactor designs

    International Nuclear Information System (INIS)

    Evaluations have been made of currently available sealing materials and concepts and their potential applicability to fusion reactor devices. The environments imposed on seals for fusion reactors are more severe than most applications. Elastomeric, metal, and welded seals were evaluated. Elastomeric materials are not effective for use at radiation dose levels greater than 108 rads; the best are polyurethane or ehtylene propylene. Welded seals and metal seals offer the advantage of realiability once a seal is made but lack the case of use inherent in elastomer seals. The sealing of a fusion reactor vacuum chamber is a non-trivial matter and will require R and D on a multitude of design options. (orig.)

  6. Engineered 3D bioimplants using elastomeric scaffold, self-assembling peptide hydrogel, and adipose tissue-derived progenitor cells for cardiac regeneration

    OpenAIRE

    Soler-botija, Carolina; Bago?, Juli R.; Llucia?-valldeperas, Aida; Valle?s-lluch, Ana; Castells-sala, Cristina; Marti?nez-ramos, Cristina; Ferna?ndez-muin?os, Teresa; Chachques, Juan Carlos; Pradas, Manuel Monleo?n; Semino, Carlos E.; Bayes-genis, Antoni

    2014-01-01

    Contractile restoration of myocardial scars remains a challenge with important clinical implications. Here, a combination of porous elastomeric membrane, peptide hydrogel, and subcutaneous adipose tissue-derived progenitor cells (subATDPCs) was designed and evaluated as a bioimplant for cardiac regeneration in a mouse model of myocardial infarction. SubATDPCs were doubly transduced with lentiviral vectors to express bioluminescent-fluorescent reporters driven by constitutively active, cardiac...

  7. Low-level laser therapy effects on pain perception related to the use of orthodontic elastomeric separators

    Scientific Electronic Library Online (English)

    Rachel D' Aurea, Furquim; Renata Correa, Pascotto; José, Rino Neto; Jefferson Rosa, Cardoso; Adilson Luiz, Ramos.

    2015-06-01

    Full Text Available INTRODUÇÃO: alguns pacientes referem-se à separação ortodôntica pré-bandagem como um procedimento doloroso. Tem sido relatado que a terapia com laser de baixa intensidade (LLLT) produz um efeito analgésico local. OBJETIVO: o objetivo deste estudo simples-cego foi investigar a percepção da dor causa [...] da por elásticos ortodônticos separadores, com ou sem uma única aplicação de LLLT (6J). MÉTODOS: a amostra foi composta por 79 indivíduos com 13-34 anos de idade no início do tratamento ortodôntico. Elásticos separadores foram colocados nos molares superiores, nas proximais mesial e distal, e mantidos por três dias. Os voluntários marcaram a intensidade da dor em uma escala visual analógica (EVA) após 6 horas, 12 horas, 1 dia, 2 dias e 3 dias. Um terço dos dentes separados recebeu aplicações de laser; outro terço, aplicações placebo; e os demais foram usados como controle. As aplicações foram realizadas segundo um desenho metodológico de boca dividida. Portanto, foram comparados três grupos: laser, placebo e controle. RESULTADOS: não foram encontradas diferenças entre os grupos, em relação à percepção de dor, em nenhum dos períodos observados. CONCLUSÕES: a utilização da LLLT em dose única não causou redução significativa na dor ortodôntica. Além disso, a percepção geral da dor devida à colocação de separadores ortodônticos variou muito e foi, geralmente, leve. Abstract in english INTRODUCTION: Some patients refer to pre-banding orthodontic separation as a painful orthodontic procedure. Low-level laser therapy (LLLT) has been reported to have local analgesic effect. OBJECTIVE: The aim of this single-blind study was to investigate the perception of pain caused by orthodontic [...] elastomeric separators with and without a single LLLT application (6J). METHODS: The sample comprised 79 individuals aged between 13 and 34 years old at orthodontic treatment onset. Elastomeric separators were placed in first maxillary molars at mesial and distal surfaces and kept in place for three days. The volunteers scored pain intensity on a visual analogue scale (VAS) after 6 and 12 hours, and after the first, second and third days. One third of patients received laser applications, whereas another third received placebo applications and the remaining ones were controls. Applications were performed in a split-mouth design. Thus, three groups (laser, placebo and control) were assessed. RESULTS: No differences were found among groups considering pain perception in all periods observed. CONCLUSION: The use of a single-dose of LLLT did not cause significant reduction in orthodontic pain perception. Overall pain perception due to orthodontic separator placement varied widely and was usually mild.

  8. Pulse-driven magnetostatic micro-actuator array based on ultrasoft elastomeric membranes for active surface applications

    Science.gov (United States)

    Streque, J.; Talbi, A.; Pernod, P.; Preobrazhensky, V.

    2012-09-01

    An array of pulse-driven magnetostatic micro-actuators with 2 mm pitch is proposed for highly deformable active surfaces. A wide range of applications can benefit from such devices, from droplet manipulation and active flow control to tactile display, for which this device was initially designed. This design ensures robustness, ease of fabrication and mass production compatibility. The device is composed of an array of 4 × 4 highly resistant elastomeric membranes achieved using microfabrication techniques. The magnetostatic actuation system is based on the interaction between a miniature coil and a SmCo micro-magnet. This mechanism was optimized by the finite-element method, leading to the introduction of different ferromagnetic circuits. Mechanical characterizations were achieved by laser interferometry. The micro-actuators can be used either in continuous mode or in pulse mode, allowing wide bandwidth, from dc to 1.5 kHz, and vibration amplitudes up to 150 ?m for instantaneous forces of 30 mN. The device has good actuation homogeneity with ±20% amplitude variations between its actuators; low crosstalk (<5%) was also demonstrated. Finally, an improved actuation design benefiting from electroplated NiFe thin films is proposed and characterized, increasing performances (forces and displacements) by 50%.

  9. Development of elastomeric lab-on-a-chip devices through Proton Beam Writing (PBW) based fabrication strategies

    International Nuclear Information System (INIS)

    In recent years, one of the most exciting developments in fluidic device applications is the rapid evolution of miniaturized micro- and nanofluidic systems, the so called 'lab-on-a-chip' devices. These devices integrate laboratory functions into a single chip, and are capable of various biochemical analysis and synthesis, such as sample injection and preparation, single cell/molecule observation, bioparticle sequencing and sorting etc. The evolvement of lab-on-a-chip concept implies the use of novel fabrication techniques for the construction of versatile analytical components in a fast and reproducible manner. Endowed with unique three-dimensional fabrication abilities, Proton Beam Writing (PBW) , which is capable of producing nanometer scaled fluidic structures with smooth and straight side wall features, has a great potential to develop all sorts of polymer fluidic devices. In this paper, we describe the batch fabrication of Poly-dimethysiloxane (PDMS) elastomeric lab-on-a-chip devices utilizing PBW technique. A series of fabrication processes, involving PBW, nickel electroplating, soft lithography, polymer dynamic coating and hydrophilic treating, were modified and adopted in our work. Subsequent characterization of individual categories of channel devices was carried out for specific fluidic studies. Respective experimental procedures are presented and results are explained. The channel devices demonstrated good fluidic performance and functionality, suggesting terformance and functionality, suggesting their further application in more complex biological investigations, and the versatility of PBW in lab-on-a-chip development.

  10. NR/EPDM elastomeric rubber blend miscibility evaluation by two-level fractional factorial design of experiment

    Science.gov (United States)

    Razak, Jeefferie Abd; Ahmad, Sahrim Haji; Ratnam, Chantara Thevy; Mahamood, Mazlin Aida; Yaakub, Juliana; Mohamad, Noraiham

    2014-09-01

    Fractional 25 two-level factorial design of experiment (DOE) was applied to systematically prepare the NR/EPDM blend using Haake internal mixer set-up. The process model of rubber blend preparation that correlates the relationships between the mixer process input parameters and the output response of blend compatibility was developed. Model analysis of variance (ANOVA) and model fitting through curve evaluation finalized the R2 of 99.60% with proposed parametric combination of A = 30/70 NR/EPDM blend ratio; B = 70°C mixing temperature; C = 70 rpm of rotor speed; D = 5 minutes of mixing period and E = 1.30 phr EPDM-g-MAH compatibilizer addition, with overall 0.966 desirability. Model validation with small deviation at +2.09% confirmed the repeatability of the mixing strategy with valid maximum tensile strength output representing the blend miscibility. Theoretical calculation of NR/EPDM blend compatibility is also included and compared. In short, this study provides a brief insight on the utilization of DOE for experimental simplification and parameter inter-correlation studies, especially when dealing with multiple variables during elastomeric rubber blend preparation.

  11. Estudo comparativo entre as diferentes cores de ligaduras elásticas / Comparative study of different colors of molded elastomeric ligatures

    Scientific Electronic Library Online (English)

    Mariana Martins e, Martins; Álvaro de Moraes, Mendes; Marco Antônio de Oliveira, Almeida; Maria Teresa de Andrade, Goldner; Viviane Ferreira, Ramos; Sarita de Sá, Guimarães.

    2006-08-01

    Full Text Available OBJETIVO: avaliar as diversas cores de ligaduras elásticas do tipo modular da marca Morelli. METODOLOGIA: estas ligaduras foram estiradas em cilindros de aço inoxidável com diâmetro aproximado de um braquete de incisivo central superior, imersas em saliva artificial a 37ºC e tiveram suas forças medi [...] das em uma máquina de ensaios de tração, antes da colocação nos estiletes (0h) e após 24 horas de imersão em saliva artificial. Os resultados foram obtidos através de um computador que opera conectado à máquina de tração e foram submetidos a testes estatísticos (ANOVA e Tuckey) com p Abstract in english AIM: the purpose of this study was to evaluate the different colors of molded elastomerics ligatures from Morelli trademark. METHODS: the ligatures were stretched over stainless dowels with a circumference approximating that of upper central incisor bracket. They were immersed in a synthetic saliva [...] bath at 37ºC and had force levels measured at initial (0h) and after 24 hours of immersion. The results were obtained from a computer connected to a traction machine and were submitted to statistical analysis (ANOVA e Tuckey) with p

  12. Synthesis and characterizations of high permittivity ultraviolet cured soft elastomeric networks and composites applicable as dielectric electroactive polymer

    DEFF Research Database (Denmark)

    Goswami, Kaustav

    2014-01-01

    The objective of this thesis was preparation and characterizations of high permittivity ultraviolet (UV) cured elastomeric networks and composites applicable as dielectric electroactive polymers (DEAPs). At present, none of the commercially available elastomers such as acrylics, poly (dimethyl siloxane) (PDMS) and polyurethanes are designed with the requirements specific for DEAPs. Thus there is a need to develop elastomers with low elastic modulus, low viscous and dielectric losses and high relative permittivity. Interpenetrating networks and fumed silica reinforced composites of poly (propylene oxide) (PPO) were prepared which showed marked improvements in properties compared to the acrylic elastomers. But difficulties in curing by industrial processes and handling of these elastomers posed as limitations. So the focus was on optimizing UV induced thiol-ene reactions for curing commercially available PDMS. UV curing of PDMS was successfully established which eliminated the major drawbacks of widely used platinum catalyzed addition curing of PDMS. An advanced sequential curing used to form the PDMS networks showed low elastic modulus and low viscous losses than the former-developed processes due to better control over the heterogeneity of the networks. The sequential curing approach was successfully used to incorporate conductive multiwalled carbon nanotubes (MWCNTs) in higher concentrations than usual without making the elastomers conductive. The PDMS-MWCNT composites also showed high relative permittivity, low elastic modulus and low viscous and dielectric losses. Thus the elastomers developed in this project show promising properties to be considered as potential DEAPs.

  13. To boost elastomer vulcanization through ionization; Pousser la vulcanisation des elastomeres par ionisation

    Energy Technology Data Exchange (ETDEWEB)

    Rouif, S. [Ionisos, 01 - Dagneux (France); Noireaux, P. [Centre de Transfert de Technologies du Mans (CTTM), 72 - Le Mans (France)

    2006-07-01

    The beta and gamma irradiation of elastomers makes easier the handling of the reticulation process in room temperature conditions and in adequate depth inside the material. The irradiation generates free radicals along the polymer chains, these radicals by combining form new chemical bonds (reticulation reaction). The irradiation of an elastomer is featured by the formation of covalent carbon-carbon type bonds while sulfur vulcanization leads to chain bridging based on sulfur-sulfur bonds. The reticulation process entails a rise of the ramification rate of the polymer. These modifications confer to the irradiated material a higher dimensional stability in high temperature conditions and in aggressive environment that may lead, in certain conditions to no need for the usual extra coating. The gamma irradiation facilities of the Ionisos company allow the treatment of molded plastic materials directly in their packaging and in bulk quantity. (A.C.)

  14. Elastomeric degradable biomaterials by photopolymerization-based CAD-CAM for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Baudis, Stefan; Nehl, Franziska; Ligon, S Clark; Liska, Robert [Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163MC, A-1060 Vienna (Austria); Nigisch, Anneliese; Bernhard, David [Department of Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Bergmeister, Helga [Core Unit for Biomedical Research, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Stampfl, Juergen, E-mail: robert.liska@tuwien.ac.at [Institute of Material Science and Technology, Vienna University of Technology, Favoritenstrasse 9-11, A-1040 Vienna (Austria)

    2011-10-15

    A predominant portion of mortalities in industrial countries can be attributed to diseases of the cardiovascular system. In the last decades great efforts have been undertaken to develop materials for artificial vascular constructs. However, bio-inert materials like ePTFE or PET fail as material for narrow blood vessel replacements (coronary bypasses). Therefore, we aim to design new biocompatible materials to overcome this. In this paper we investigate the use of photoelastomers for artificial vascular constructs since they may be precisely structured by means of additive manufacturing technologies. Hence, 3D computer aided design and manufacturing technologies (CAD-CAM) offer the possibility of creating cellular structures within the grafts that might favour ingrowth of tissue. Different monomer formulations were screened concerning their suitability for this application but all had drawbacks, especially concerning the suture tear resistance. Therefore, we chose to modify the original network architecture by including dithiol chain transfer agents which effectively co-react with the acrylates and reduce crosslink density. A commercial urethane diacrylate was chosen as base monomer. In combination with reactive diluents and dithiols, the properties of the photopolymers could be tailored and degradability could be introduced. The optimized photoelastomers were in good mechanical accordance with native blood vessels, showed good biocompatibility in in vitro tests, degraded similar to poly(lactic acid) and were successfully manufactured with the 3D CAD-CAM technology.

  15. Elastomeric degradable biomaterials by photopolymerization-based CAD-CAM for vascular tissue engineering

    International Nuclear Information System (INIS)

    A predominant portion of mortalities in industrial countries can be attributed to diseases of the cardiovascular system. In the last decades great efforts have been undertaken to develop materials for artificial vascular constructs. However, bio-inert materials like ePTFE or PET fail as material for narrow blood vessel replacements (coronary bypasses). Therefore, we aim to design new biocompatible materials to overcome this. In this paper we investigate the use of photoelastomers for artificial vascular constructs since they may be precisely structured by means of additive manufacturing technologies. Hence, 3D computer aided design and manufacturing technologies (CAD-CAM) offer the possibility of creating cellular structures within the grafts that might favour ingrowth of tissue. Different monomer formulations were screened concerning their suitability for this application but all had drawbacks, especially concerning the suture tear resistance. Therefore, we chose to modify the original network architecture by including dithiol chain transfer agents which effectively co-react with the acrylates and reduce crosslink density. A commercial urethane diacrylate was chosen as base monomer. In combination with reactive diluents and dithiols, the properties of the photopolymers could be tailored and degradability could be introduced. The optimized photoelastomers were in good mechanical accordance with native blood vessels, showed good biocompatibility in in vitro tests, degrd biocompatibility in in vitro tests, degraded similar to poly(lactic acid) and were successfully manufactured with the 3D CAD-CAM technology.

  16. MCU MATERIALS COMPATIBILITY WITH CSSX SOLVENT

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F

    2006-01-13

    The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) plans to use several new materials of construction not previously used with CSSX solvent. SRNL researchers tested seven materials proposed for service in seal and gasket applications. None of the materials leached detectable amounts of components into the CSSX solvent during 96 hour tests. All are judged acceptable for use based on their effect on the solvent. However, some of the materials adsorbed solvent or changed dimensions during contact with solvent. Consultation with component and material vendors with regard to performance impact and in-use testing of the materials is recommended. Polyetheretherketone (PEEK), a material selected for use in contactor bearing seals, did not gain weight or change dimensions on contact with CSSX solvent. Analysis of the solvent contacted with this material showed no impurities and the standard dispersion test gave acceptable phase separation results. The material contains a leachable hydrocarbon substance, detectable on exposed surfaces, that did not adversely contaminate the solvent within the limits of the testing. We recommend contacting the vendor to determine the source and purpose of this component, or, alternatively, pursue the infrared analysis of the PEEK in an effort to better define potential impacts.

  17. Simulation of Payne effect of elastomeric isolators with a harmonic balance method

    OpenAIRE

    Jaumouille?, Vincent; Sinou, Jean-jacques; Petitjean, Benoi?t

    2012-01-01

    In the presented work, a non linear effect of rubber referred as Fletcher-Gent effect or Payne effect is investigated. It leads to a change in the rubber dynamic modulus with vibration amplitudes and, consequently, modifies resonance frequencies of mechanical systems including non linear elastomers. In this study a new methodology is developed to take into account Payne effect in a linear viscoelastic rubber material. Small vibration amplitudes around a no-preloaded state are predicted by con...

  18. Self-standing elastomeric composites based on lithium ferrites and their dielectric behavior

    Science.gov (United States)

    Soreto Teixeira, S.; Graça, M. P. F.; Dionisio, M.; Ilcíkova, M.; Mosnacek, J.; Spitalsky, Z.; Krupa, I.; Costa, L. C.

    2014-12-01

    Lithium ferrite (LiFe5O8) is an attractive material for technological applications due to its physical properties, which are significantly dependent on the preparation method and raw materials. In this work, LiFe5O8 crystallites were obtained by controlled heat-treatment process at 1100 °C, of a homogeneous mixture of Li2O-Fe2O3 powders, prepared by wet ball-milling and using lithium and iron nitrates as raw materials. The main goal was the preparation of a flexible and self-standing tick composite film by embedding lithium ferrite particles in a polymeric matrix, taking advantage of the good mechanical properties of the polymer and of the electrical and dielectric properties of the ferrite. The selected polymer matrix was styrene-b-isoprene-b-styrene copolymer. To prepare the composites, the lithium ferrite particles were chemically modified in order to functionalize their surface. To analyse the influence of the particles surface modification, different composites were made, with modified and unmodified particles. The structure of the obtained composites was studied by FTIR, XRD, TGA, and DSC techniques. The dielectric properties were analysed, in the frequency range between 10 Hz and 1 MHz and in function of temperature in the range between -73 °C and 127 °C. These properties were related with the structure and concentration of the particles in the matrix network. The composites with the modified particles present higher dielectric constant, maintaining values of loss tangent sufficiently low (<10-2) that can be considered interesting for technological applications.

  19. From deep clays to expanded graphite: towards the modelling of porous materials

    International Nuclear Information System (INIS)

    Compared with standard mechanics, modelling the behaviour of porous materials requires and extended framework. Known as 'poro-mechanics', such an approach has recently been implemented in Aster finite element code. Two examples of its use for engineering purposes are presented in this paper. First, the water pressure rise and the resulting mechanical strains in the clay surrounding a deep disposal of nuclear waste is analysed. The second example concerns the tightness of expanded graphite gaskets which are widely used in the bolted assemblies of EDF nuclear reactors. Other engineering fields such as civil engineering are likely to benefit from this theory, and are mentioned in the conclusion. (authors)

  20. Remifentalino intravenoso mediante infusor elastomerico frente a meperidina intramuscular: Estudio comparativo en analgesia obstetrica / Intravenous remifentanil delivered through an elastomeric device versus intramuscular meperidine comparative study for obstetric analgesia

    Scientific Electronic Library Online (English)

    E., Calderón; E., Martínez; M. D., Román; A., Pernio; R., García-Hernández; L.M, Torres.

    2006-10-01

    Full Text Available Objetivos: Evaluar la eficacia y seguridad de remifentanilo administrado mediante infusor elastomérico con PCA iv en analgesia obstétrica comparado con meperidina intramuscular en parturientas con contraindicación para analgesia epidural. Material y Método: Se seleccionaron aletoriamente 24 parturie [...] ntas, se asoció infusor elastomérico Baxter® con 250 ml de suero fisiológico con 2,5 mg de remifentanilo y un ritmo de 12 ml·h ¹, lo que supone una infusión media de 0,025 ?g·kg-1·min-1 de remifentanilo, permitiendo la administración de bolos de 5 ml con un tiempo de cierre de 30 minutos (Grupo R) o 1 mg·kg¹ de meperidina y 2,5 mg de haloperidol (Grupo M) vía intramuscular cada 4 h. Valoramos la intensidad del dolor cada 30 min mediante una escala analógica visual (EVA), tiempo de infusión, bolos administrados, el nivel de sedación mediante escala del estado de alerta y sedación evaluada por el observador (OAA/S), efectos adversos y el test de Apgar del recién nacido al minuto y a los 5 min. Resultados: No hubo diferencias en los datos antropométricos de ambos grupos. La duración media de la infusión en el grupo R fue de 280 ± 55 min y las necesidades de bolos de rescate de 1,2 ± 1,5. La dosis media de meperidina intramuscular en el grupo M fue de 120 ± 25 mg. La intensidad del dolor durante el parto fue significativamente menor en el grupo R durante todo el periodo de dilatación y expulsivo (p Abstract in english Objectives: To evaluate the effectiveness and security of remifentanil administered by means of elastomeric infusor with PCA IV compared obstetrical analgesia with intramuscular meperidine in obstetric patients with contraindication for epidural analgesia, Material and Method: 24 patients were rando [...] mized, an elastomeric infusor Baxter® with a capacity of 250 ml was filled with 2.5 mg of remifentanil and a 12 mililiter·h-1, was satarted, (average infusion of 0.025·kg-1·min-1 of remifentanil, and boluses of 5 ml with a time of closing of 30 minutes (Group R) or 1 mg/kg-1 of meperidine and 2.5 mg of haloperidol (Group M) every 4 h by IM route. We valued the intensity of pain each 30 min by means of a visual analogical scale (EVA), time of infusion, boluses administered, level of sedatión by means of scale of the alert status and sedatión evaluated by observer (OAA/S), adverse effects and the Apgar test of new born to 1 and 5 min. Results: There were no differences in the anthropometric data of both groups. The average duration of the infusion in group R was of 280 ± 55 min and the necessities of boluses of 1.2 rescue of ± 1,5. The average dose of intramuscular meperidine in group M was of 120 ± 25 mg. The intensity of the pain during the childbirth was significantly smaller in group R (p

  1. Analgesia invasiva domiciliaria en el manejo del dolor postoperatorio en cirugía mayor ambulatoria mediante bombas elastoméricas intravenosas Home invasive analgesia in the management of postoperative pain alter outpatient major surgery using intravenous elastomeric pumps

    Directory of Open Access Journals (Sweden)

    R. Rodríguez de la Torre

    2011-06-01

    Full Text Available Introducción: el dolor postoperatorio moderado-severo sigue siendo un problema en cirugía ambulatoria, ya que provoca problemas de flujo de pacientes, retrasando el alta de los pacientes, siendo uno de los principales motivos de reingreso en los hospitales, y por tanto un importante indicador de calidad de estas Unidades. El empleo de técnicas analgésicas invasivas domiciliarias, en todos sus regímenes, puede controlar el dolor postoperatorio en estas intervenciones y permitir incluirlas en los programas de cirugía ambulatoria. Objetivos: el objetivo de nuestro estudio es valorar la viabilidad y la seguridad de la utilización de bombas de perfusión continua elastoméricas para la administración de analgesia endovenosa continua domiciliaria, a la vez que valorar la eficacia analgésica y el grado de satisfacción de los pacientes intervenidos en régimen ambulatorio. Material y métodos: estudio retrospectivo de 463 pacientes. Una vez intervenidos bajo estrategia de analgesia multimodal, se les coloca dos tipos diferentes de bombas elastoméricas endovenosas (elastómero de dexketoprofeno o de metamizol. La intensidad del dolor, para evaluar la necesidad de analgesia de rescate, se cuantifica con la escala visual analógica o con la escala verbal simple. En el domicilio (24 horas tras la cirugía, la Unidad de Atención Domiciliaria revisa los efectos secundarios, alteraciones del sueño, intensidad del dolor, necesidad de analgesia de rescate y grado de satisfacción. Resultados: un 69% de los pacientes presentaron dolor de carácter leve o ausencia de dolor tras la intervención y únicamente 16 de los 463 pacientes presentaron dolor de carácter severo. El 27% de los pacientes necesitaron analgesia de rescate y un 9% de los pacientes presentaron efectos secundarios atribuibles a los fármacos analgésicos (4% vómitos, 2% mareos, 2,5% somnolencia y 0,5% insomnio. Ningún paciente tuvo que ser reingresado después del alta. Un 83% de los pacientes mostró un alto grado de satisfacción, un 16% de los pacientes satisfacción moderada y un 0,2% poca satisfacción. Conclusión: nuestro estudio demuestra la viabilidad y seguridad de la utilización de infusores elastoméricos endovenosos como método de analgesia postoperatoria, que permiten controlar los casos de dolor moderado a severo en procedimientos aplicados a la cirugía ambulatoria. Sin embargo se necesitan más estudios comparativos con técnicas analgésicas convencionales, así como con diferentes regímenes de infusión.Introduction: moderate to severe postoperative pain is still a problem in outpatient surgery, since it causes patient flow problems and delays the discharge of patients, being one of the major causes of re-hospitalization and hence a relevant quality indicator of these Units. The use of home invasive analgesic techniques, in all their regimes, can be effective for the management of postoperative pain in these surgical procedures and allow them to be included in outpatient surgery programs. Objectives: the aim of our study was to determine the feasibility and safety of the use of elastomeric continuous perfusion pumps for the administration of home continuous endovenous analgesia, as well as to assess analgesic effectiveness and degree of satisfaction of patients undergoing outpatient surgerys. Material and methods: we conducted a simple retrospective study in 463 patients. After the surgical procedure was performed under multimodal analgesia, two differents elastomeric endovenous pumps (dexketoprofeno pump or metamizol pump were used. Pain intensity by means of a visual analog scale and a plain oral scale, the need for supplemental analgesics. At home (24 hours after the surgical operation, the Home Care Unit checked side effects, sleep disorders, pain intensity, need of rescue analgesia and degree of satisfaction. Results: 69% of the patients report absence or slight pain 24 h after the surgical operation, just 16 out of 463 patients of the study had severe pain. The 27% of patients required rescue therapy and the 9

  2. Analgesia invasiva domiciliaria en el manejo del dolor postoperatorio en cirugía mayor ambulatoria mediante bombas elastoméricas intravenosas / Home invasive analgesia in the management of postoperative pain alter outpatient major surgery using intravenous elastomeric pumps

    Scientific Electronic Library Online (English)

    R., Rodríguez de la Torre; E., Medina Madrid; M. L., Dávila Arias; A., Pérez García; A., Torres López; E., Cuéllar Obispo.

    2011-06-01

    Full Text Available Introducción: el dolor postoperatorio moderado-severo sigue siendo un problema en cirugía ambulatoria, ya que provoca problemas de flujo de pacientes, retrasando el alta de los pacientes, siendo uno de los principales motivos de reingreso en los hospitales, y por tanto un importante indicador de cal [...] idad de estas Unidades. El empleo de técnicas analgésicas invasivas domiciliarias, en todos sus regímenes, puede controlar el dolor postoperatorio en estas intervenciones y permitir incluirlas en los programas de cirugía ambulatoria. Objetivos: el objetivo de nuestro estudio es valorar la viabilidad y la seguridad de la utilización de bombas de perfusión continua elastoméricas para la administración de analgesia endovenosa continua domiciliaria, a la vez que valorar la eficacia analgésica y el grado de satisfacción de los pacientes intervenidos en régimen ambulatorio. Material y métodos: estudio retrospectivo de 463 pacientes. Una vez intervenidos bajo estrategia de analgesia multimodal, se les coloca dos tipos diferentes de bombas elastoméricas endovenosas (elastómero de dexketoprofeno o de metamizol). La intensidad del dolor, para evaluar la necesidad de analgesia de rescate, se cuantifica con la escala visual analógica o con la escala verbal simple. En el domicilio (24 horas tras la cirugía), la Unidad de Atención Domiciliaria revisa los efectos secundarios, alteraciones del sueño, intensidad del dolor, necesidad de analgesia de rescate y grado de satisfacción. Resultados: un 69% de los pacientes presentaron dolor de carácter leve o ausencia de dolor tras la intervención y únicamente 16 de los 463 pacientes presentaron dolor de carácter severo. El 27% de los pacientes necesitaron analgesia de rescate y un 9% de los pacientes presentaron efectos secundarios atribuibles a los fármacos analgésicos (4% vómitos, 2% mareos, 2,5% somnolencia y 0,5% insomnio). Ningún paciente tuvo que ser reingresado después del alta. Un 83% de los pacientes mostró un alto grado de satisfacción, un 16% de los pacientes satisfacción moderada y un 0,2% poca satisfacción. Conclusión: nuestro estudio demuestra la viabilidad y seguridad de la utilización de infusores elastoméricos endovenosos como método de analgesia postoperatoria, que permiten controlar los casos de dolor moderado a severo en procedimientos aplicados a la cirugía ambulatoria. Sin embargo se necesitan más estudios comparativos con técnicas analgésicas convencionales, así como con diferentes regímenes de infusión. Abstract in english Introduction: moderate to severe postoperative pain is still a problem in outpatient surgery, since it causes patient flow problems and delays the discharge of patients, being one of the major causes of re-hospitalization and hence a relevant quality indicator of these Units. The use of home invasiv [...] e analgesic techniques, in all their regimes, can be effective for the management of postoperative pain in these surgical procedures and allow them to be included in outpatient surgery programs. Objectives: the aim of our study was to determine the feasibility and safety of the use of elastomeric continuous perfusion pumps for the administration of home continuous endovenous analgesia, as well as to assess analgesic effectiveness and degree of satisfaction of patients undergoing outpatient surgerys. Material and methods: we conducted a simple retrospective study in 463 patients. After the surgical procedure was performed under multimodal analgesia, two differents elastomeric endovenous pumps (dexketoprofeno pump or metamizol pump) were used. Pain intensity by means of a visual analog scale and a plain oral scale, the need for supplemental analgesics. At home (24 hours after the surgical operation), the Home Care Unit checked side effects, sleep disorders, pain intensity, need of rescue analgesia and degree of satisfaction. Results: 69% of the patients report absence or slight pain 24 h after the surgical operation, just 16 out of 463 patients of the study had severe pain. The 27% of pa

  3. Molecular scale buckling mechanics in individual aligned single-wall carbon nanotubes on elastomeric substrates.

    Science.gov (United States)

    Khang, Dahl-Young; Xiao, Jianliang; Kocabas, Coskun; MacLaren, Scott; Banks, Tony; Jiang, Hanqing; Huang, Yonggang Y; Rogers, John A

    2008-01-01

    We have studied the scaling of controlled nonlinear buckling processes in materials with dimensions in the molecular range (i.e., approximately 1 nm) through experimental and theoretical studies of buckling in individual single-wall carbon nanotubes on substrates of poly(dimethylsiloxane). The results show not only the ability to create and manipulate patterns of buckling at these molecular scales, but also, that analytical continuum mechanics theory can explain, quantitatively, all measurable aspects of this system. Inverse calculation applied to measurements of diameter-dependent buckling wavelengths yields accurate values of the Young's moduli of individual SWNTs. As an example of the value of this system beyond its use in this type of molecular scale metrology, we implement parallel arrays of buckled SWNTs as a class of mechanically stretchable conductor. PMID:18072798

  4. Active materials by four-dimension printing

    Science.gov (United States)

    Ge, Qi; Qi, H. Jerry; Dunn, Martin L.

    2013-09-01

    We advance a paradigm of printed active composite materials realized by directly printing glassy shape memory polymer fibers in an elastomeric matrix. We imbue the active composites with intelligence via a programmed lamina and laminate architecture and a subsequent thermomechanical training process. The initial configuration is created by three-dimension (3D) printing, and then the programmed action of the shape memory fibers creates time dependence of the configuration—the four-dimension (4D) aspect. We design and print laminates in thin plate form that can be thermomechanically programmed to assume complex three-dimensional configurations including bent, coiled, and twisted strips, folded shapes, and complex contoured shapes with nonuniform, spatially varying curvature. The original flat plate shape can be recovered by heating the material again. We also show how the printed active composites can be directly integrated with other printed functionalities to create devices; here we demonstrate this by creating a structure that can assemble itself.

  5. Rumen metabolism and absorption of a 14C-labelled elastomeric copolymer and its value as a roughage substitute for cattle

    International Nuclear Information System (INIS)

    Several synthetic elastomeric and plastomeric polymers were tested for suitability as artificial roughages. They were fed to rumenfistulated cattle fed grain only. Several of the polymers were regurgitated, remasticated and reswallowed, and they formed thin strands of intermeshed fiber that produced a large, loosely woven hay-like mass that floated on the rumen contents. An elastomeric polymer consisting of copolymers of 80 to 90% ethylene and 10 to 20% propylene, with a tensile strength at yield of 45.7 kg/cm2, a hardness of 30 units (Shore D hardness scale) and a tensile strength at 300% elongation of 51.0 kg/cm2, was selected for further testing. The copolymer was fed at about 90 g/head daily for 127 days to cattle fed grain only. At slaughter, rumens contained an average of 8.0 kg copolymer (dry basis). Cattle fed the copolymer had healthier rumen papillae and epithelia of the abomasum and small intestines than did control animals fed grain only. Using 14C-labeled copolymer, we found that the copolymer was not degraded by rumen microorganisms or acid-pepsin solution. When 14C-labeled copolymer was fed to milking cows, no 14C activity was found in milk, blood or urine. Upon slaughter, about 100% of the 14C activity was recovered from digesta and feces. We concluded that the copolymer was not absorbed from the digestive tract

  6. Preliminary studies of radioactive wastes immobilization, using microwaves, in asphaltic matrices and elastomeric residues

    International Nuclear Information System (INIS)

    The present work consists of preliminary studies for immobilization of radioactive waste by using monolithic solid matrices compounded by bitumen (asphalt) and production leftovers of EVA shoe soles (polymeric residues). Those matrices were obtained through high microwave energy heating aiming to reduce possible dispersion of radioactive material in the environment during the stages of intermediate storage, transportation and final disposal. The radioactive waste that was used results from the purification of thorium long made at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). The obtained precipitate is named Retoter (thorium residue and rare earth elements). The compounded samples of bitumen and rubber were heated by electromagnetic radiation (high microwave energy); the time was varied and the temperature was controlled. Variables such as mass percent of bitumen/rubber, dosage, microwave power, heating period and temperature were analyzed in order to get the most homogeneous formulations that might be most resistant to environmental agents. The geometry of samples is still being studied to obtain the best distribution of radioactive waste on the polymeric compound (bitumen/rubber). To prove the efficiency of the method, physics and chemistry characterizations have been initially made through assays in order to evidence properties like: porosity, density, leaching rate, resistance to radiation, resistance to aging, thermal, mechanical and structural pging, thermal, mechanical and structural properties. (author)

  7. High friction on ice provided by elastomeric fiber composites with textured surfaces

    Science.gov (United States)

    Rizvi, R.; Naguib, H.; Fernie, G.; Dutta, T.

    2015-03-01

    Two main applications requiring high friction on ice are automobile tires and footwear. The main motivation behind the use of soft rubbers in these applications is the relatively high friction force generated between a smooth rubber contacting smooth ice. Unfortunately, the friction force between rubber and ice is very low at temperatures near the melting point of ice and as a result we still experience automobile accidents and pedestrian slips and falls in the winter. Here, we report on a class of compliant fiber-composite materials with textured surfaces that provide outstanding coefficients of friction on wet ice. The fibrous composites consist of a hard glass-fiber phase reinforcing a compliant thermoplastic polyurethane matrix. The glass-fiber phase is textured such that it is aligned transversally and protruding out of the elastomer surface. Our analysis indicates that the exposed fiber phase exhibits a "micro-cleat" effect, allowing for it to fracture the ice and increase the interfacial contact area thereby requiring a high force to shear the interface.

  8. Enabling Desktop Nanofabrication with the Targeted Use of Soft Materials

    Science.gov (United States)

    Eichelsdoerfer, Daniel James

    This thesis focuses on the application of soft materials to scanning probe-based molecular printing techniques, such as dip-pen nanolithography (DPN). The selective incorporation of soft materials in place of hard materials in traditional cantilever-based scanning probe lithography (SPL) systems not only enables the deposition of a broader range of materials, but also dramatically lowers the cost while simultaneously increasing the throughput of SPL. Chapter 1 introduces SPL and DPN, and highlights a few recent advances in using DPN to control surface chemical functionality at the nanoscale. In addition to introducing the material deposition capabilities of DPN, Chapter 1 introduces the development of the cantilever-free architecture, a relatively recent paradigm shift in high-throughput SPL. Furthermore, an in-depth synthetic methodology for making the most widely used cantilever-free tip arrays, consisting of elastomeric nanoscale pens adhered to an elastomeric backing layer on a glass slide, is included as an appendix. Chapter 2 discusses the synthesis of metal and metal oxide nanoparticles at specified locations by using DPN to deposit the precursors dispersed in a polymer matrix; after deposition, the precursors are annealed to form single nanoparticles. This work builds on previous soft material-based advances in DPN by utilizing the polymer as a "nanoreactor" to synthesize the desired nanoparticles, where the precursors can diffuse and coalesce into a single nanoparticle within each spot. The process of precursor aggregation and single nanoparticle formation is studied, and it is found that metal precursors follow one of three pathways based upon their reduction potential. Chapter 3 is the first of three chapters that highlights the power of soft materials in the cantilever-free architecture. In particular, Chapter 3 examines the role of the elastomeric backing layer as a compliant spring whose stiffness (as measured by the spring constant, k) can be tuned with a simple chemical change to the composition of the elastomer. In particular, the extent of cross-linking within the elastomer is found to dictate the k the backing layer, and arrays with spring constants tuned from 7 to 150 N/m are described. Furthermore, a simple geometric model is developed that explains the low variation of k within each cantilever-free array; this stands in contrast to arrays of cantilevers, which typically show large variations of k within an array. Chapter 4 addresses the problem of individual actuation in SPL by embedding resistive heaters directly beneath the elastomeric backing layer. This actuation scheme was chosen because the elastomer used in the cantilever-free tip arrays has extraordinary thermal expansion properties, and thorough exploration of their actuation behavior shows that the heater arrays are fast (> 100 microm/s) and powerful (> 4 microm) enough for actuation. After implementing several corrections for the tip height -- a problem that is intractable without the heaters, and has never been addressed before -- printing of alkanethiols onto Au is demonstrated with a 2D array of individually actuated probes. Chapter 5 examines the hypothesis that elastomeric tips can absorb solvent and be used to transport materials in the absence of environmental solvent. This is evaluated by first using tip arrays soaked in a nonpolar solvent to pattern a hydrophobic block copolymer that cannot be patterned by traditional DPN, and is subsequently explored for the case of water uptake into the pen arrays. Surprisingly, despite their poor water retention ability, the tip arrays can store enough water to pattern hydrophilic polymers in dry environments for over 2 hours. The dynamics of the solvent absorption are captured by a simple calculation that accounts for the dynamical behavior of water retention and the backing layer thickness, thereby allowing these results to be generalized to other solvents. This exploration of the subtle and dynamic role of absorbed solvent in cantilever-free pen arrays shows that proper pr

  9. Estudo comparativo entre as diferentes cores de ligaduras elásticas Comparative study of different colors of molded elastomeric ligatures

    Directory of Open Access Journals (Sweden)

    Mariana Martins e Martins

    2006-08-01

    Full Text Available OBJETIVO: avaliar as diversas cores de ligaduras elásticas do tipo modular da marca Morelli. METODOLOGIA: estas ligaduras foram estiradas em cilindros de aço inoxidável com diâmetro aproximado de um braquete de incisivo central superior, imersas em saliva artificial a 37ºC e tiveram suas forças medidas em uma máquina de ensaios de tração, antes da colocação nos estiletes (0h e após 24 horas de imersão em saliva artificial. Os resultados foram obtidos através de um computador que opera conectado à máquina de tração e foram submetidos a testes estatísticos (ANOVA e Tuckey com pAIM: the purpose of this study was to evaluate the different colors of molded elastomerics ligatures from Morelli trademark. METHODS: the ligatures were stretched over stainless dowels with a circumference approximating that of upper central incisor bracket. They were immersed in a synthetic saliva bath at 37ºC and had force levels measured at initial (0h and after 24 hours of immersion. The results were obtained from a computer connected to a traction machine and were submitted to statistical analysis (ANOVA e Tuckey with p<0.05. RESULTS AND CONCLUSION: the medium values were md=0.3792KgF for 0h and md=0.1286KgF for 24h and the percentage of force decay were 66.07% ± 2.31%. The results revealed statically differences between forces delivered in 0h and 24h. At 0h, there were differences statistically significance between some colors of ligatures before the action of the time and the immersion in artificial saliva bath, with higher values for the pearl (md=0.4024KgF and minors values for the slight green (md=0.3511KgF. At 24h, it was also find differences statistically significances between some colors, but the distribution was different than the observed at 0h. The slight green, red, yellow and white colors had the minor percentage of force decay, in which slight green showed the best behavior (62.60%. However, the pearl, silver and gray had the highest percentage of force decay, with pearl showing the worst behavior (69.23%.

  10. Controlling cell-material interactions with polymer nanocomposites by use of surface modifying additives

    Science.gov (United States)

    Poole-Warren, L. A.; Farrugia, B.; Fong, N.; Hume, E.; Simmons, A.

    2008-11-01

    Polymer nanocomposites (NC) are fabricated by incorporating well dispersed nanoscale particles within a polymer matrix. This study focuses on elastomeric polyurethane (PU) based nanocomposites, containing organically modified silicates (OMS), as bioactive materials. Nanocomposites incorporating chlorhexidine diacetate as an organic modifier (OM) were demonstrated to be antibacterial with a dose dependence related to both the silicate loading and the loading of OM. When the non-antibacterial OM dodecylamine was used, both cell and platelet adhesion were decreased on the nanocomposite surface. These results suggest that OM is released from the polymer and can impact on cell behaviour at the interface. Nanocomposites have potential use as bioactive materials in a range of biomedical applications.

  11. Morphology and viscoelastic properties of sealing materials based on EPDM rubber.

    Science.gov (United States)

    Mili?, J; Aroguz, A; Budinski-Simendi?, J; Radicevi?, R; Prendzov, S

    2008-12-01

    In this applicative study, the ratio of active and inactive filler loadings was the prime factor for determining the dynamic-mechanical behaviour of ethylene-propylene-diene monomer rubbers. Scanning electron microscopy was used to study the structure of reinforced dense and microcellular elastomeric materials. The effects of filler and blowing agent content on the morphology of composites were investigated. Microcellular samples cured in salt bath show smaller cells and uniform cell size compared with samples cured in hot air. Dynamic-mechanical thermal analysis showed appreciable changes in the viscoelastic properties by increasing active filler content, which could enable tailoring the material properties to suit sealing applications. PMID:19094042

  12. Modular glovebox connector and associated good practices for control of radioactive and chemically toxic materials

    International Nuclear Information System (INIS)

    Design and associated good practices are described for a modular glovebox connector to improve control of radioactive and chemically toxic materials. The connector consists of an anodized aluminum circular port with a mating spacer, gaskets, and retaining rings for joining two parallel ends of commercially available or custom-manufactured glovebox enclosures. Use of the connector allows multiple gloveboxes to be quickly assembled or reconfigured in functional units. Connector dimensions can be scaled to meet operational requirements for access between gloveboxes. Options for construction materials are discussed, along with recommendations for installation of the connector in new or retrofitted systems. Associated good practices include application of surface coatings and caulking, use of disposable glovebags, and proper selection and protection of gasket and glove materials. Use of the connector at an inhalation toxicology research facility has reduced the time and expense required to reconfigure equipment for changing operational requirements, the dispersion of contamination during reconfigurations, and the need for decommissioning and disposal of contaminated enclosures

  13. Bio-Inspired Wide-Angle Broad-Spectrum Cylindrical Lens Based on Reflections from Micro-Mirror Array on a Cylindrical Elastomeric Membrane

    Directory of Open Access Journals (Sweden)

    Chi-Chieh Huang

    2014-06-01

    Full Text Available We present a wide-angle, broad-spectrum cylindrical lens based on reflections from an array of three-dimensional, high-aspect-ratio micro-mirrors fabricated on a cylindrical elastomeric substrate, functionally inspired by natural reflecting superposition compound eyes. Our device can perform one-dimensional focusing and beam-shaping comparable to conventional refraction-based cylindrical lenses, while avoiding chromatic aberration. The focal length of our cylindrical lens is 1.035 mm, suitable for micro-optical systems. Moreover, it demonstrates a wide field of view of 152° without distortion, as well as modest spherical aberrations. Our work could be applied to diverse applications including laser diode collimation, barcode scanning, holography, digital projection display, microlens arrays, and optical microscopy.

  14. An in vitro comparison of the force decay generated by different commercially available elastomeric chains and NiTi closed coil springs Comparação in vitro da degradação da força gerada por cadeias elastoméricas e por molas fechadas de NiTi de diferentes marcas comerciais

    OpenAIRE

    Ana Cristina Soares Santos; André Tortamano; Sandra Regina Frazatto Naccarato; Gladys Cristina Dominguez-Rodriguez; Julio Wilson Vigorito

    2007-01-01

    This in vitro study was designed to compare the forces generated by commercially available elastomeric chains and NiTi closed coil springs, and to determine their force decay pattern. Forty elastomeric chains and forty NiTi closed coil springs were divided into 4 groups according to the following manufacturers: (1) Morelli®, (2) Abzil®, (3) TP Orthodontics® and (4) American Orthodontics®. The specimens were extended to twice their original length and stored in artificial saliva at 37°...

  15. Corrosion and stress corrosion cracking of bolting materials in light water reactors

    International Nuclear Information System (INIS)

    The primary coolant of a pressurized water reactor contains dissolved boric acid added as a soluble neutron absorber. Corrosion and stress corrosion cracking of bolts on pumps and on primary system manways have occurred where gaskets leak this boric acid onto the low alloy steel bolting material. Laboratory experiments have shown that the concentration of the boric acid to a moist paste at approximately the boiling point of water can produce corrosion rates of the order of several tenths of an inch per year on bolting and piping materials, which values are consistent with service experience. Frequently molybdenum disulfide is used as a lubricant for tightening bolts on massive flanges. Laboratory experience has shown that when the primary coolant leaks through a gasket the molybdenum disulfide can react with the leaking steam to produce hydrogen sulfide and subsequent stress corrosion cracking of the bolts. Additionally, contaminants concentrating over significant time periods have caused stress corrosion cracking failures of reactor coolant pump internals. Failure analysis of cracked bolts from service and the results of laboratory tests that demonstrate these mechanisms of bolt cracking are presented

  16. Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens

    International Nuclear Information System (INIS)

    Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirement for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon – even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reducedation control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry – specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test methods have been developed that deliver accurate and repeatable data, which will be described.

  17. Investigation of test methods, material properties, and processes for solar cell encapsulants. Eighteenth quarterly progress report, August 12-November 12, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Willis, P. B.; Baum, B.; Davis, M.

    1980-12-01

    The goal of this program is to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. A survey was made of elastomers for use as gaskets for the photovoltaic module. Of the wide variety of materials examined EPDM offered the optimum combination of low compression set and low cost. The preference for EPDM is borne out by its long history of use as an automobile gasket. The commercial availability of materials that would be useful for sealants between the edge of the module and the gasket was investigated. Butyl sealants have the best combination of physical properties, low cost and a well-documented history of performance. A preferred composition has not yet been identified. One laminating type pottant ethylene/methyl acrylate copolymer (EMA), and two casting polymers, polybutyl acrylate and polyurethane, have been under investigation this past quarter. An EMA formulation has been developed which is easily extrudable and cures to a high gel content. So far only one commercial US source (Quinn) of aliphatic polyurethane has been located. Work is continuing to improve reaction rate as well as to eliminate source(s) of bubble formation during module fabrication. Considerable effort was spent in developing an improved polybutyl acrylate casting formulation providing high gel. Many viable curing systems are now available: however, the best formulation considering physical properties, freedom from bubbles as well as cure time utilizes Lupersol II (aliphatic peroxide) initiator. This initiator gives the desired gel after 20 minute cure at 45/sup 0/C or 12 minute cure at 55/sup 0/C.

  18. Micromechanics and constitutive models for soft active materials with phase evolution

    Science.gov (United States)

    Wang, Binglian

    Soft active materials, such as shape memory polymers, liquid crystal elastomers, soft tissues, gels etc., are materials that can deform largely in response to external stimuli. Micromechanics analysis of heterogeneous materials based on finite element method is a typically numerical way to study the thermal-mechanical behaviors of soft active materials with phase evolution. While the constitutive models that can precisely describe the stress and strain fields of materials in the process of phase evolution can not be found in the databases of some commercial finite element analysis (FEA) tools such as ANSYS or Abaqus, even the specific constitutive behavior for each individual phase either the new formed one or the original one has already been well-known. So developing a computationally efficient and general three dimensional (3D) thermal-mechanical constitutive model for soft active materials with phase evolution which can be implemented into FEA is eagerly demanded. This paper first solved this problem theoretically by recording the deformation history of each individual phase in the phase evolution process, and adopted the idea of effectiveness by regarding all the new formed phase as an effective phase with an effective deformation to make this theory computationally efficient. A user material subroutine (UMAT) code based on this theoretical constitutive model has been finished in this work which can be added into the material database in Abaqus or ANSYS and can be easily used for most soft active materials with phase evolution. Model validation also has been done through comparison between micromechanical FEA and experiments on a particular composite material, shape memory elastomeric composite (SMEC) which consisted of an elastomeric matrix and the crystallizable fibre. Results show that the micromechanics and the constitutive models developed in this paper for soft active materials with phase evolution are completely relied on.

  19. Dental materials in Papua New Guinea: a survey of dental clinics.

    Science.gov (United States)

    Stewart, B L; Pouru, S

    1990-03-01

    Questionnaires were distributed to 55 Public Health and Defence Force dental clinics throughout Papua New Guinea in order to ascertain storage and clinical conditions, as well as information related to the type, consumption and performance of alginate and elastomeric impression materials and composite restorative materials. Of the 39 respondents, representing a 71% return, few reported any problems with either of the two types of impression materials. However, complaints associated with the use of paste-paste composites, Adaptic and Concise, were a major concern. It was assumed that the problems were caused by exposure to excessively high temperatures during shipment, distribution and storage of these materials throughout Papua New Guinea. Alternative materials, which are less sensitive to heat, were proposed for use in Papua New Guinea. These were a light-activated composite (Durafill), a powder-liquid composite (Powderlite) and a powder-water glass ionomer (Chemfil II). PMID:2346047

  20. The influence of filler on the properties of elastomeric materials based on poly(ethylene-co-propylene-co-2-ehylidene-5-norbornene rubber

    Directory of Open Access Journals (Sweden)

    Budinski-Simendi? Jaroslava

    2006-01-01

    Full Text Available Crosslinked samples based on poly(ethylene-co-propylene-co-2-ehylidene5-norbornene EPDM rubber, carbon black as active filler and natural chalk as inactive filler were cured with sulphur. The content of carbon black was varied from 100 to 200 pph. The content of chalk was varied from 0 to 100 pph. The content of paraffin oil was also varied in some samples. The compounds were prepared by mixing ingredients on a laboratory two-roll mill. Vulcanizates were prepared by curing at 180°C. Various methods were used for the physical and mechanical characterizations. The dynamic mechanical properties of the elastomers were measured in the temperature range from -120 to 80°C.

  1. The influence of filler on the properties of elastomeric materials based on poly(ethylene-co-propylene-co-2-ehylidene-5-norbornene) rubber

    OpenAIRE

    Budinski-Simendi? Jaroslava; Milic Jelena; Cvetkovi? Ivana; Radi?evi? Radmila; Korugi?-Karasz Ljiljana; Vukov Miodrag; Mirkovi? Desa

    2006-01-01

    Crosslinked samples based on poly(ethylene-co-propylene-co-2-ehylidene5-norbornene) EPDM rubber, carbon black as active filler and natural chalk as inactive filler were cured with sulphur. The content of carbon black was varied from 100 to 200 pph. The content of chalk was varied from 0 to 100 pph. The content of paraffin oil was also varied in some samples. The compounds were prepared by mixing ingredients on a laboratory two-roll mill. Vulcanizates were prepared by curing at 180°C. Various...

  2. Engineered 3D bioimplants using elastomeric scaffold, self-assembling peptide hydrogel, and adipose tissue-derived progenitor cells for cardiac regeneration.

    Science.gov (United States)

    Soler-Botija, Carolina; Bagó, Juli R; Llucià-Valldeperas, Aida; Vallés-Lluch, Ana; Castells-Sala, Cristina; Martínez-Ramos, Cristina; Fernández-Muiños, Teresa; Chachques, Juan Carlos; Pradas, Manuel Monleón; Semino, Carlos E; Bayes-Genis, Antoni

    2014-01-01

    Contractile restoration of myocardial scars remains a challenge with important clinical implications. Here, a combination of porous elastomeric membrane, peptide hydrogel, and subcutaneous adipose tissue-derived progenitor cells (subATDPCs) was designed and evaluated as a bioimplant for cardiac regeneration in a mouse model of myocardial infarction. SubATDPCs were doubly transduced with lentiviral vectors to express bioluminescent-fluorescent reporters driven by constitutively active, cardiac tissue-specific promoters. Cells were seeded into an engineered bioimplant consisting of a scaffold (polycaprolactone methacryloyloxyethyl ester) filled with a peptide hydrogel (PuraMatrix™), and transplanted to cover injured myocardium. Bioluminescence and fluorescence quantifications showed de novo and progressive increases in promoter expression in bioactive implant-treated animals. The bioactive implant was well adapted to the heart, and fully functional vessels traversed the myocardium-bioactive implant interface. Treatment translated into a detectable positive effect on cardiac function, as revealed by echocardiography. Thus, this novel implant is a promising construct for supporting myocardial regeneration. PMID:24936221

  3. Ultra-high-precision alignment of the elastomerically mounted elements of the science camera lenses for the Mars Science Laboratory (MSL) rover

    International Nuclear Information System (INIS)

    Cameras built for space exploration are required to meet stringent environmental conditions, such as thermal and dynamic loads for both the optics (camera lens) and imaging electronics. On a multitude of spaceborne imaging instruments, optical elements are supported in their mounts via an elastomeric bonding approach using a room temperature vulcanizing silicone as the bonding agent. Employing this integration method, we achieved element-to-element alignment, measured as the total indicated runout, using a high-precision contact probe to be on the order of half a wavelength of He-Ne laser light, or 0.3 ?m, on the Malin Space Science Systems lenses for the Mars Science Laboratory (MSL) cameras. This is a higher precision than the current industry state-of-the-art, and it was achieved for the very challenging small diameter lens elements. This paper describes the design philosophy, implementation, and integration method that resulted in achieving this level of precision for interelement alignment. The results are based on actual measurements that were made during the process of building the MSL rover's science camera lenses, namely Mastcams, the Mars Hand Lens Imager, and the Mars Descent Imager. The optical designs of these cameras lenses are described in detail in [Opt. Eng.48, 103002 (2009)10.1117/1.3251343], while further information on the four science cameras can be found at http://www.msss.com.

  4. Physics-Based Simulation and Experiment on Blast Protection of Infill Walls and Sandwich Composites Using New Generation of Nano Particle Reinforced Materials

    Science.gov (United States)

    Irshidat, Mohammad

    A critical issue for the development of nanotechnology is our ability to understand, model, and simulate the behavior of small structures and to make the connection between nano structure properties and their macroscopic functions. Material modeling and simulation helps to understand the process, to set the objectives that could guide laboratory efforts, and to control material structures, properties, and processes at physical implementation. These capabilities are vital to engineering design at the component and systems level. In this research, experimental-computational-analytical program was employed to investigate the performance of the new generation of polymeric nano-composite materials, like nano-particle reinforced elastomeric materials (NPREM), for the protection of masonry structures against blast loads. New design tools for using these kinds of materials to protect Infill Walls (e.g. masonry walls) against blast loading were established. These tools were also extended to cover other type of panels like sandwich composites. This investigation revealed that polymeric nano composite materials are strain rate sensitive and have large amount of voids distributed randomly inside the materials. Results from blast experiments showed increase in ultimate flexural resistance achieved by both unreinforced and nano reinforced polyurea retrofit systems applied to infill masonry walls. It was also observed that a thin elastomeric coating on the interior face of the walls could be effective at minimizing the fragmentation resulting from blast. More conclusions are provided with recommended future research.

  5. Correlation of electrical reactor cable failure with materials degradation

    International Nuclear Information System (INIS)

    Complete circuit failure (shortout) of electrical cables typically used in nuclear power plant containments is investigated. Failure modes are correlated with the mechanical deterioration of the elastomeric cable materials. It is found that for normal reactor operation, electrical cables are reliable and safe over very long periods. During high temperature excursions, however, cables pulled across corners under high stress may short out due to conductor creep. Severe cracking will occur in short times during high temperatures (>1500C) and in times of the order of years at elevated temperatures (1000C to 1400C). A theoretical treatment of stress distribution responsible for creep and for cracking by J.E. Reaugh of Science Applications, Inc. is contained in the Appendix. 29 refs., 32 figs

  6. Performance characteristics of O-ring seals for radioactive material packages when subjected to extreme temperatures

    International Nuclear Information System (INIS)

    Performance requirements for radioactive material (RAM) packages are specified in Title 10, Code of Federal Regulations, Part 71 (10CFR71). Seals that provide the containment system interface between the packaging body and closure must function in both high and low temperature environments which are characteristic of the hypothetical fire accident and the -40F (233 K)1 normal transport condition, respectively. A research and testing program has been initiated at Sandia National Laboratories to examine the performance of elastomeric O-ring seal materials commonly used in RAM packages during the temperature extremes. Performance characteristics including permeation times, static compression set, and leakage rate versus temperature and time are being examined using helium or neon as the tracer gas. The results of this study can be used as an aid to package designers when selecting O-ring seal materials for specific applications

  7. An Analysis of the Macroscopic Tensile Behavior of a Nonlinear Nylon Reinforced Elastomeric Composite System Using MAC/GMC

    Science.gov (United States)

    Assaad, Mahmoud; Arnold, Steven M.

    1999-01-01

    A special class of composite laminates composed of soft rubbery matrices and stiff reinforcements made of steel wires or synthetic fibers is examined, where each constituent behaves in a nonlinear fashion even in the small strain domain. Composite laminates made of piles stacked at alternating small orientation angles with respect to the applied axial strain are primarily dominated by the nonlinear behavior of the reinforcing fibers. However; composites with large ply orientations or those perpendicular to the loading axis, will approximate the behavior of the matrix phase and respond in even a more complex fashion for arbitrarily stacked piles. The geometric nonlinearity due to small cord rotations during loading was deemed here to have a second order effect and consequently dropped from any consideration. The user subroutine USRMAT within the Micromechanics Analysis Code with the Generalized Method of Cells (MAC/GMC), was utilized to introduce the constituent material nonlinear behavior. Stress-strain behavior at the macro level was experimentally generated for single and multi ply composites comprised of continuous Nylon-66 reinforcements embedded in a carbon black loaded rubbery matrix. Comparisons between the predicted macro composite behavior and experimental results are excellent when material nonlinearity is included in the analysis. In this paper, a brief review of GMC is provided, along with a description of the nonlinear behavior of the constituents and associated constituent constitutive relations, and the improved macro (or composite) behavior predictions are documented and illustrated.

  8. Laser 3D Printing with Sub-Microscale Resolution of Porous Elastomeric Scaffolds for Supporting Human Bone Stem Cells.

    Science.gov (United States)

    Petrochenko, Peter E; Torgersen, Jan; Gruber, Peter; Hicks, Lucas A; Zheng, Jiwen; Kumar, Girish; Narayan, Roger J; Goering, Peter L; Liska, Robert; Stampfl, Jürgen; Ovsianikov, Aleksandr

    2015-04-01

    A reproducible method is needed to fabricate 3D scaffold constructs that results in periodic and uniform structures with precise control at sub-micrometer and micrometer length scales. In this study, fabrication of scaffolds by two-photon polymerization (2PP) of a biodegradable urethane and acrylate-based photoelastomer is demonstrated. This material supports 2PP processing with sub-micrometer spatial resolution. The high photoreactivity of the biophotoelastomer permits 2PP processing at a scanning speed of 1000 mm s(-1) , facilitating rapid fabrication of relatively large structures (>5 mm(3) ). These structures are custom printed for in vitro assay screening in 96-well plates and are sufficiently flexible to enable facile handling and transplantation. These results indicate that stable scaffolds with porosities of greater than 60% can be produced using 2PP. Human bone marrow stromal cells grown on 3D scaffolds exhibit increased growth and proliferation compared to smooth 2D scaffold controls. 3D scaffolds adsorb larger amounts of protein than smooth 2D scaffolds due to their larger surface area; the scaffolds also allow cells to attach in multiple planes and to completely infiltrate the porous scaffolds. The flexible photoelastomer material is biocompatible in vitro and is associated with facile handling, making it a viable candidate for further study of complex 3D-printed scaffolds. PMID:25522214

  9. Insulation for sanitary and heating systems. Manufacturing of elastomer insulation materials; Daemmung von Anlagen im Sanitaer- und Heizungsbereich. Was ist bei der Verarbeitung von elastomeren Daemmstoffen zu beachten?

    Energy Technology Data Exchange (ETDEWEB)

    Helms, H.; Weber, M. [Armacell (Germany)

    2001-12-01

    The following article presents the insulation of sanitary and heating systems and what is mentionable. Elastomer materials like from manufacturer SH/Armaflex offer good physical properties and due to their extraordinary flexibility are installed properly and quickly. [German] Bei Daemmungen von Anlagen im Sanitaer- und Heizungsbereich sind einige grundsaetzliche Dinge zu beachten, die im folgenden Artikel dargestellt werden. Elastomere Daemmstoffe, wie das vom Hersteller angebotene Produkt SH/Armaflex, bieten gute physikalischtechnische Werte und sind aufgrund ihrer ausserordentlichen Flexibilitaet sauber und schnell zu verarbeiten. (orig.)

  10. Propriedades reométricas e mecânicas e morfologia de compósitos desenvolvidos com resíduos elastoméricos vulcanizados / Cure characteristics, mechanical properties and morphology of composites developed with addition of elastomeric vulcanized ground scraps

    Scientific Electronic Library Online (English)

    Aline, Zanchet; Nicolle, Dal’Acqua; Tatiana, Weber; Janaina S., Crespo; Rosmary N., Brandalise; Regina C. R., Nunes.

    2007-03-01

    Full Text Available Uma alternativa para as empresas geradoras de resíduos elastoméricos é a incorporação dos mesmos em suas formulações. Esse trabalho tem como objetivo preparar compósitos a partir da incorporação de resíduos industriais de SBR (copolímero de butadieno-estireno) e de EPDM (terpolímero de etileno-propi [...] leno-dieno), em formulação ASTM específica para cada tipo de elastômero. Foram avaliadas as propriedades reométricas, mecânicas e morfológicas dos compósitos desenvolvidos. A incorporação do resíduo permitiu a obtenção de produtos que vulcanizam em menores tempos quando comparados a composições sem resíduo. A quantidade de resíduo, para o melhor resultado de resistência à tração foi de 37 e de 196 phr para os compósitos com SBR e EPDM, respectivamente. As micrografias de MEV corroboraram os resultados mecânicos dessas composições, indicando melhor homogeneidade do resíduo na respectiva matriz elastomérica. Abstract in english One alternative for elastomeric scraps generation is its incorporation in conventional formulations in the industry itself. In this work, compositions with incorporation of SBR (styrene butadiene rubber) and EPDM (ethylene propylene diene rubber) industrial scraps, in specific ASTM formulation for e [...] ach elastomer, were prepared. Rheometric characteristics, mechanical properties and the morphology of the compounds developed were evaluated. With the ground scraps incorporation the vulcanization time decreases, comparing with compounds without ground scraps. The amount of scraps for the best tensile strength properties was 37 and 196 phr for SBR and EPDM compositions, respectively. Micrographs corroborated the mechanical results, indicating the best homogeneity of the scraps in the elastomeric matrix for these compositions.

  11. Propriedades reométricas e mecânicas e morfologia de compósitos desenvolvidos com resíduos elastoméricos vulcanizados Cure characteristics, mechanical properties and morphology of composites developed with addition of elastomeric vulcanized ground scraps

    Directory of Open Access Journals (Sweden)

    Aline Zanchet

    2007-03-01

    Full Text Available Uma alternativa para as empresas geradoras de resíduos elastoméricos é a incorporação dos mesmos em suas formulações. Esse trabalho tem como objetivo preparar compósitos a partir da incorporação de resíduos industriais de SBR (copolímero de butadieno-estireno e de EPDM (terpolímero de etileno-propileno-dieno, em formulação ASTM específica para cada tipo de elastômero. Foram avaliadas as propriedades reométricas, mecânicas e morfológicas dos compósitos desenvolvidos. A incorporação do resíduo permitiu a obtenção de produtos que vulcanizam em menores tempos quando comparados a composições sem resíduo. A quantidade de resíduo, para o melhor resultado de resistência à tração foi de 37 e de 196 phr para os compósitos com SBR e EPDM, respectivamente. As micrografias de MEV corroboraram os resultados mecânicos dessas composições, indicando melhor homogeneidade do resíduo na respectiva matriz elastomérica.One alternative for elastomeric scraps generation is its incorporation in conventional formulations in the industry itself. In this work, compositions with incorporation of SBR (styrene butadiene rubber and EPDM (ethylene propylene diene rubber industrial scraps, in specific ASTM formulation for each elastomer, were prepared. Rheometric characteristics, mechanical properties and the morphology of the compounds developed were evaluated. With the ground scraps incorporation the vulcanization time decreases, comparing with compounds without ground scraps. The amount of scraps for the best tensile strength properties was 37 and 196 phr for SBR and EPDM compositions, respectively. Micrographs corroborated the mechanical results, indicating the best homogeneity of the scraps in the elastomeric matrix for these compositions.

  12. Accuracy of stone casts obtained by different impression materials

    Directory of Open Access Journals (Sweden)

    Adriana Cláudia Lapria Faria

    2008-12-01

    Full Text Available Several impression materials are available in the Brazilian marketplace to be used in oral rehabilitation. The aim of this study was to compare the accuracy of different impression materials used for fixed partial dentures following the manufacturers' instructions. A master model representing a partially edentulous mandibular right hemi-arch segment whose teeth were prepared to receive full crowns was used. Custom trays were prepared with auto-polymerizing acrylic resin and impressions were performed with a dental surveyor, standardizing the path of insertion and removal of the tray. Alginate and elastomeric materials were used and stone casts were obtained after the impressions. For the silicones, impression techniques were also compared. To determine the impression materials' accuracy, digital photographs of the master model and of the stone casts were taken and the discrepancies between them were measured. The data were subjected to analysis of variance and Duncan's complementary test. Polyether and addition silicone following the single-phase technique were statistically different from alginate, condensation silicone and addition silicone following the double-mix technique (p .05 to alginate and addition silicone following the double-mix technique, but different from polysulfide. The results led to the conclusion that different impression materials and techniques influenced the stone casts' accuracy in a way that polyether, polysulfide and addition silicone following the single-phase technique were more accurate than the other materials.

  13. Fabrication and characterization of elastomeric scaffolds comprised of a citric acid-based polyester/hydroxyapatite microcomposite

    International Nuclear Information System (INIS)

    Highlights: • Porous scaffolds were prepared from polymer/hydroxyapatite (POC/HA) composite. • The pore size was designed to be uniform for all POC/HA composite scaffolds. • Compression strength and modulus are dependent on HA concentration within composite. - Abstract: In this paper we describe an effective technical route for the production of porous scaffolds from microcomposite material consistent of citric acid-based polyester elastomer and hydroxyapatite microparticles with potential use in tissue engineering applications. Fabricated scaffolds were characterized by field emission electron microscopy, Fourier-transform infra-red spectroscopy, thermal gravimetric analysis and mechanical tests. We demonstrate that the chemical composition, scaffold morphology, mechanical integrity and porosity of the produced microcomposite scaffolds are strongly affected by variation of the initial hydroxyapatite concentration in the mineral-polymer mixture during the fabrication process. This polyester/mineral scaffold exhibits versatility in compression modulus and strength in the range of 21.72–33.25 KPa and 49.92–101.48 KPa respectively, corresponding to the hydroxyapatite concentration in the composite (10–30 wt.%)

  14. "Material" mechanics of materials

    Directory of Open Access Journals (Sweden)

    Maugin Gérard A.

    2002-01-01

    Full Text Available The paper outlines recent developments and prospects in the application of the continuum mechanics expressed intrinsically on the material manifold itself. This includes applications to materially inhomogeneous materials physical effects which, in this vision, manifest themselves as quasi-in homogeneities, and the notion of thermo dynamical driving force of the dissipative progress of singular point sets on the material manifold with special emphasis on fracture, shock waves and phase-transition fronts. .

  15. Sealing Materials for Use in Vacuum at High Temperatures

    Science.gov (United States)

    Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

    2012-01-01

    Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

  16. Evaluation of Ion Exchange Materials in K Basin Floor Sludge and Potential Solvents for PCB Extraction from Ion Exchange Materials

    International Nuclear Information System (INIS)

    Approximately 73 m3 of heterogeneous solid material, ''sludge,'' (upper bound estimate, Packer 1997) have accumulated at the bottom of the K Basins in the 100 K Area of the Hanford Site. This sludge is a mixture of spent fuel element corrosion products, ion exchange materials (organic and inorganic), graphite-based gasket materials, iron and aluminum metal corrosion products, sand, and debris (Makenas et al. 1996, 1997). In addition, small amounts of polychlorinated biphenyls (PCBs) have been found. These small amounts are significant from a regulatory standpoint. Ultimately, it is planned to transfer the K Basins sludge to the Hanford double shell tanks (DSTs). Chemical pretreatment is required to address criticality issues and the destruction or removal of PCBs before the K Basin sludge can be transferred to the DSTs. Eleven technologies have been evaluated (Papp 1997) as potential pretreatment methods. Based on the evaluations and engineering studies and limited testing, Fluor Daniel Hanford recommended solvent washing of the K Basin sludge, followed by nitric acid dissolution and, potentially, peroxide addition (FDH 1997). The solvent washing (extraction) and peroxide addition would be used to facilitate PCB removal and destruction. Following solvent extraction, the PCBs could be distilled and concentrated for disposal as a low-level waste. The purpose of the work reported here was to continue investigating solvent extraction, first by better identifying the ion exchange materials in the actual sludge samples and then evaluating various solvents for removing the PCBs or possibly dissolving the resins. This report documents some of the process knowledge on ion exchange materials used and spilled in the K Basins and describes the materials identified from wet sieving KE Basin floor and canister sludge and the results of other analyses. Several photographs are included to compare materials and illustrate material behavior. A summary of previous tests on solvent extraction of PCB surrogates from simulant K Basin sludge is also given

  17. Compatibility of refrigerants and lubricants with elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, G.R.; Seiple, R.H.

    1992-07-01

    Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  18. Compatibility of refrigerants and lubricants with elastomers. Quarterly report, 1 April 1992--30 June 1992

    Energy Technology Data Exchange (ETDEWEB)

    Hamed, G.R.; Seiple, R.H.

    1992-07-01

    Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  19. Orthodontic materials research and applications: part 2. Current status and projected future developments in materials and biocompatibility.

    Science.gov (United States)

    Eliades, Theodore

    2007-02-01

    The purpose of this 2-part opinion article was to project the developments expected to occur in the next few years in orthodontic materials research and applications. Part 1 reviewed developments in bonding to enamel. Part 2 looks at other orthodontic materials applications and explores emerging research strategies for probing the biological properties of materials. In the field of metallic brackets, expansion of the use of titanium alloys with improved hardness and nickel-free steels with better corrosion resistance and increased hardness is expected. Manufacturing techniques might be modified to include laser-welding methods and metal injection molding. Esthetic bracket research will involve the synthesis of high-crystallinity biomedical polymers with increased hardness and stiffness, decreased water sorption, and improved resistance to degradation. New plastic brackets might incorportate ceramic wings. Fiber-reinforced composite archwires, currently experimental, could soon be commercially available, and long-term applications of shape-memory plastics might become viable. Advancements in elastomeric materials will result in polymers with reduced relaxation, broader use of fluoride-releasing elastomers with decreased relaxation, and large-scale film coating of elastomers to decrease reactivity, water sorption, and degradation. Finally, biocompatibility assessments will incorporate testing of potential endocrinological action. New polymer formulations might be tested in adhesive and plastic bracket manufacturing, based on benzoic ring-free monomers to avoid the adverse effects of the estrogenic molecule bisphenol-A. PMID:17276868

  20. Avaliação do desempenho de materiais absorvedores de radiação eletromagnética por guia de ondas / Performance of radar absorbing materials by waveguide measurements

    Scientific Electronic Library Online (English)

    Magali S., Pinho; Roberto C., Lima; Bluma G., Soares; Regina C. R., Nunes.

    1999-12-01

    Full Text Available Neste trabalho, amostras elastoméricas contendo diferentes tipos de cargas absorvedoras de microondas, sob a forma de pós, foram obtidas para medidas de refletividade. Os materiais utilizados com diferentes composições percentuais em peso foram: ferrocarbonila, negro de fumo, polianilina e ferrita d [...] opadas. As medidas de refletividade foram determinadas com base nas propriedades magnéticas e dielétricas dos compósitos elastoméricos a partir de dados de espalhamento, através da inserção e fixação em um guia de ondas, para a faixa de freqüência de 8-16 GHz. Os melhores resultados foram apresentados pelo ferrocarbonila e negro de fumo para as freqüências mais baixas, enquanto a ferrita dopada absorveu em uma freqüência mais elevada. Abstract in english In this work, samples consisting of an elastomeric matrix containing different kinds of active material in particulate form were prepared for reflectivity measurements. The materials used in different contents were: carbonyl-iron, carbon black, doped polyaniline and doped ferrite. The microwave refl [...] ectivity levels were determined from the magnetic and dielectric properties of the elastomeric composites from scattering data, by fitting the samples in a waveguide, for measurements in the frequency range of 8-16 GHz. Better microwave absorption at low frequencies was obtained for carbonyl-iron and carbon black while doped ferrite absorbed at high frequencies.

  1. Efecto de la composición del bloque elastomérico de SBS y SEBES en las propiedades reológicas de asfaltos modificados / On the effect of the composition of the elastomeric block of SBS and SEBES block polymers on the rheological properties of modified aphalts

    Scientific Electronic Library Online (English)

    R., Herrera-Najera; G., García-Guzmán; H., Xicotencalt-Serrano; L., Medina-Torres.

    2012-04-01

    Full Text Available Se estudió el comportamiento de los asfaltos modificados (AMP) con polímeros SBS (Lote 416) y SEBES a fin de entender el efecto de la composición del bloque elastomérico de esos dos tipos de polímeros en la morfología y la reología de los AMP. Los polímeros SEBES fueron producidos por hidrogenación [...] homogénea de los SBS con diferente grado de saturación de las dobles ligaduras de polibutadieno (0%, 7%, 29% y 49%). Los asfaltos modificados (AMP) con un 10% de polímero fueron preparados por mezclado a altas temperaturas (1880 0C, 4 h, 5000 rpm). Los análisis de microscopia por fluorescencia indican que el AMP es un material heterogeneo con una fase rica en polímero y otra fase rica en asfalto. Los análisis reológicos en flujo oscilatorio para varias temperaturas (40 a 90ºC) indican que los AMP producidos con SEBES con alta saturación experimentan cambios estructurales dando un incremento de su respuesta con respecto a la frecuencia, y exhibiendo una mas alta elasticidad (G'>G"). Se empleó el modelo multimodal de Maxwell para reproducir G' y G" de las curvas maestras. Se observó que el número de modos para ajustar los datos de los AMP aumentan con el grado de saturación. Abstract in english The behaviour of asphalt (PMA) modified with SBS (lot 416) and SBEBS was studied to elucidate the effect of the composition of the elastomeric block of these two types of polymers on the morphology and rheology of PMAs. The SBEBS polymers were produced by homogeneous hydrogenation of the SBS having [...] different degree of saturation of poly-butadiene double bonds (0%), 7%, 29% and 49%). Asphalt modified samples (PMA) with 10 wt % of polymer were prepared by hot mixing proces j (180 °C, 4 hours, 5000 rpm). Fluorescence microscopic analysis indicated that PMA are heterogeneous materials exhibiting a polymer-rich and asphalts-rich phases. Oscillatory flow rheology analysis for various temperatures (40-90ºC) indicate that all PMA prepared with SBEBS with higher saturation degree undergo structural c h angei exhibiting a higher viscoelastic response, and higher elasticity (G'>G"). The Maxwell multimodal model was employed to reproduce G' and G" master curves. It was observed thai the number of relaxation modes required to fit the data of SBEBS modified asphalt increases with the degree of polybutadiene saturation, since 12 modes are need are for SBEBS with 49 % of saturation while 8 modes are enough to fit the data of SBEBS 7 % of saturation.

  2. Mechanics of Re-Torquing in Bolted Flange Connections

    Science.gov (United States)

    Gordon, Ali P.; Drilling Brian; Weichman, Kyle; Kammerer, Catherine; Baldwin, Frank

    2010-01-01

    It has been widely accepted that the phenomenon of time-dependent loosening of flange connections is a strong consequence of the viscous nature of the compression seal material. Characterizing the coupled interaction between gasket creep and elastic bolt stiffness has been useful in predicting conditions that facilitate leakage. Prior advances on this sub-class of bolted joints has lead to the development of (1) constitutive models for elastomerics, (2) initial tightening strategies, (3) etc. The effect of re-torque, which is a major consideration for typical bolted flange seals used on the Space Shuttle fleet, has not been fully characterized, however. The current study presents a systematic approach to characterizing bolted joint behavior as the consequence of sequentially applied torques. Based on exprimenta1 and numerical results, the optimal re-torquing parameters have been identified that allow for the negligible load loss after pre-load application

  3. Characterisation of Materials used in Flex Bearings of Large Solid Rocket Motors

    Directory of Open Access Journals (Sweden)

    CH.V. Ram Mohan

    2011-04-01

    Full Text Available Solid rocket motors are propulsion devices for both satellite launchers and missiles, which require guidance and steering to fly along a programmed trajectory and to compensate for flight disturbances. A typical solid rocket motor consists of motor case, solid propellant grain, motor insulation, igniter and nozzle. In most solid rocket motors, thrust vector control (TVC is required. One of the most efficient methods of TVC is by flex nozzle system. The flex nozzle consists of a flexible bearing made of an elastomeric material alternating with reinforcement rings of metallic or composite material. The material characterisation of AFNOR 15CDV6 steel and the natural rubber-based elastomer developed for use in flex nozzle are discussed. This includes testing, modelling of the material, selection of a material model suitable for analysis, and the validation of material model.Defence Science Journal, 2011, 61(3, pp.264-269, DOI:http://dx.doi.org/10.14429/dsj.61.52

  4. Contrast Materials

    Science.gov (United States)

    What are contrast materials and how do they work? Contrast materials, also called contrast agents or contrast media, are used to improve pictures ... top of page Which imaging exams use contrast materials? Oral Contrast Materials Barium-sulfate contrast materials that ...

  5. Hazardous materials

    Science.gov (United States)

    HazCom; Hazard communication; Material Safety Data Sheet; MSDS ... Hazardous materials are substances that could harm human health or the environment. Hazardous means dangerous, so these materials must ...

  6. Nanotechnology Materials

    Science.gov (United States)

    This page contains learning materials on specific materials related to nanotechnology. A number of materials on crystals are currently provided. Links to educational videos, discussion questions, a laboratory exercise and slides are provided. These materials are available for download in PowerPoint and PDF file formats.

  7. Understanding Materials

    Science.gov (United States)

    Katsioloudis, Petros J.

    2010-01-01

    Almost everything people have ever done has involved materials. Historical evidence indicates that "engineered materials" have been available and utilized for the benefit of humankind since the Neolithic period, beginning about 10,000 BC. Some of these materials have been in existence for thousands of years. At first, materials consisted of wood,…

  8. Materials Chemistry

    CERN Document Server

    Fahlman, Bradley D

    2011-01-01

    The 2nd edition of Materials Chemistry builds on the strengths that were recognized by a 2008 Textbook Excellence Award from the Text and Academic Authors Association (TAA). Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property treatment, providing a suitable breadth and depth coverage of the rapidly evolving materials field. The 2nd edition continues to offer innovative coverage and practical perspective throughout. After briefly defining materials chemistry and its history, seven chapters discuss solid-state chemistry, metals, semiconducting materials, organic "soft" materials, nanomaterials, and materials characterization. All chapters have been thoroughly updated and expanded with, for example, new sections on ‘soft lithographic’ patterning, ‘click chemistry’ polymerization, nanotoxicity, graphene, as well as many biomaterials applications. The polymer and ‘soft’ materials chapter represents the largest expansion for the 2nd edition. Each ch...

  9. Functional materials

    International Nuclear Information System (INIS)

    It is a compilation of chapters written by active researchers and offer information and critical insights about semiconducting materials and devices, dielectric and ferroelectric materials, magnetic materials, composites and other functional materials. In the book, the functional materials are discussed from the mixed valences and stoichiometry points of view, to understand the structural evolution and transformation of different material systems - in particular, the role played by crystal structures in property control of functional materials using advanced characterization techniques. The book examines the properties, soft-chemistry preparations, electronic structures and crystal structures of transition and rare earth metals and their oxides. The book presents a strong argument that functional materials system is the future direction of the multidisciplinary research involving physics, chemistry, materials science and electrical engineering, with emphasis on device applications. Papers relevant to INIS are indexed separately

  10. Long term integrity of spent fuel and construction materials for dry storage facilities

    International Nuclear Information System (INIS)

    In Japan, two dry storage facilities at reactor sites have already been operating since 1995 and 2002, respectively. Additionally, a large scale dry storage facility away from reactor sites is under safety examination for license near the coast and desired to start its operation in 2010. Its final storage capacity is 5,000tU. It is therefore necessary to obtain and evaluate the related data on integrity of spent fuels loaded into and construction materials of casks during long term dry storage. The objectives are: - Spent fuel rod: To evaluate hydrogen migration along axial fuel direction on irradiated claddings stored for twenty years in air; To evaluate pellet oxidation behaviour for high burn-up UO2 fuels; - Construction materials for dry storage facilities: To evaluate long term reliability of welded stainless steel canister under stress corrosion cracking (SCC) environment; To evaluate long term integrity of concrete cask under carbonation and salt attack environment; To evaluate integrity of sealability of metal gasket under long term storage and short term accidental impact force.

  11. Materials technology assessment of high temperature solar receivers for fuels and chemicals production

    Science.gov (United States)

    Tiegs, T. N.

    1981-07-01

    Current interest in using solar thermal energy to produce fuels and chemicals has prompted an assessment of materials technology for five proposed designs of solar receivers. The principal process of interest is water splitting. Reaction schemes considered involve the high temperature decomposition of sulfuric acid, and silicon carbide is the structural ceramic material usually considered most resistant to the conditions of this reaction. Hence we have assessed the fabricability of the designs from SiC for that reaction system, even though most designs envision use with air, helium, or nitrogen as a heat transfer medium. Honeycomb and hemispherical dome receivers have been fabricated from SiC. A receiver using planar coiled tubes has been fabricated from cordierite but not from SiC. Fabrication has not been demonstrated for helical coil and long tube designs. The last three of these should be fabricable with up to two years development. All lack the ultimate test: operational experience. The need for reliable seals is common to all designs. Metallic gaskets are subject to corrosion, and ceramic and mechanical seals have not been demonstrated for the anticipated thermal cycling.

  12. Important concepts in cool engineering insulation technique. Part 5. Processing of elastomer insulation materials. Gluing method; Belangrijke begrippen in de koeltechnische isolatietechniek. Deel 5. Verwerking van elastomeer isolatiemateriaal. De juiste manier van verlijmen

    Energy Technology Data Exchange (ETDEWEB)

    Helms, H. [Armacell, Muenster (Germany)

    2006-01-15

    In a series of articles background information is given of cooling engineering insulation. In part 1 attention is paid to condensation and prevention of condensation. In the second article the author discusses physical properties that effect insulation thickness, the importance of the heat conduction coefficient and water vapor diffusion. In part 3 the correct application of elastomeric insulation is dealt with, in part 4 attention is paid to diffusion of water vapor, and in this part the subject is the processing of elastomers, focusing on the method of gluing the materials together. [Dutch] Isoleren is een vak waarin fouten en foutjes venijnig worden afgestraft. In koeltechnische installaties speelt dat nog sterker. Daarom worden in een serie vaktechnische artikelen de achtergronden van koel-technische isolatie onder de loep genomen. In de eerste bijdrage komen condensvorming en het voorkomen daarvan aan de orde. In volgende afleveringen behandelt de auteur de natuurkundige verschijnselen die de gewenste isolatiedikte beinvloeden, de betekenis van de warmtegeleidingscoefficient (deel 3) en waterdampdiffusie (deel 4). Twee artikelen over correcte toepassing van elastomere isolatie ronden de vaktechnische serie af, waarvan dit artikel de eerste is.

  13. Material problems

    International Nuclear Information System (INIS)

    For the development and realisation of HTR reactors, modern high-temperature materials must be adapted to nuclear demands, and special materials must be developed. The paper discusses some aspects of structural materials for core shutdown components with a special view to HTR reactors. (orig./ORU)

  14. Laser materials

    CERN Document Server

    Gan, Fuxi

    1995-01-01

    This book focuses mainly on the spectroscopy of laser materials, physics of laser materials, laser crystals and laser glasses. The spectroscopic and laser properties of rare earth and transition metal ion-doped solid state materials are systematically described based on modern quantum optics. The aim of this book is to relate the laser and spectroscopic properties to the structure and chemical composition of materials. It emphasises the nonlinear optical effects in laser materials, which are widely used in high power laser systems. The development of advanced solid state laser devices depends

  15. The effect of material difference and flange nominal size on the sealing performance of new gasketless flanges

    International Nuclear Information System (INIS)

    This paper deals with a new seal system between flange joints without using a gasket. This gasketless flange includes a groove and an annular lip that is machined in one of the flange rings which when removed being in contact with the other flange to form a seal line when the flanges are assembled. In this study, firstly, fundamental dimensions are examined for unplasticized polyvinyl chloride (PVC-U JIS) to obtain the best sealing performance. Then, the effects of material difference and flange nominal size upon the sealing performance of the new gasketless flange are investigated for two types of materials, 0.25% carbon steel (S25C JIS) and PVC-U. It is found that the critical internal pressure at which leakage appears is mainly controlled by the maximum stress at the annular lip for each material even if the flange nominal sizes are different. The gasketless flange made by PVC-U shows the higher critical internal pressure compared with the case of S25C if the same clamping forces are applied. The effect of stress relaxation for PVC-U on the sealing performance is also considered. Then, it may be concluded that this PVC-U gasketless flange as well as S25C has good sealing performance

  16. Static seals and their application in water-cooled nuclear reactor systems

    International Nuclear Information System (INIS)

    Information relative to six types of static seals commonly used in the primary cooling systems of nuclear reactors is compiled. This information includes a description of each type of seal, its material of construction, design features, operating experience, and advantages and disadvantages. The types covered include spiral-wound asbestos-filled gaskets, hollow metallic O-rings, Belleville spring type of gasketed joints, integrated elastomer and metal retainer gaskets, and solid metal gaskets with heavy cross sections. Omega, canopy, and lip seals are discussed briefly, and information on flange design for gasketing is also presented

  17. Dielectric elastomer actuators using Slide-Ring Material® with increased permittivity

    Science.gov (United States)

    Tsuchitani, Shigeki; Sunahara, Tokiharu; Miki, Hirofumi

    2015-06-01

    The inclusion of high permittivity nanoparticles in elastomeric materials for dielectric elastomer actuators (DEAs) is one promising method to achieve large strain at relatively low applied voltages. However, the addition of these nanoparticles tends to increase the stiffness of the elastomer and disturbs the actuation of the DEA. This is attributed to restriction of the chain motion in the elastomer by the nanoparticles. Slide-Ring Material® (SRM) is a cross-linked polymeric material with freely movable cross-linking sites. The internal stresses in this structure are dramatically homogenized by the pulley effect; therefore, the restriction of chain motion due to the nanoparticles is expected to be significantly reduced. We have employed SRM as a host elastomer for a DEA with the addition of ferroelectric BaTiO3 (BT) nanoparticles. The effects of BT addition on the permittivity, stiffness and viscosity of the SRM–BT nanocomposites, and the actuation strain of DEAs using SRM were evaluated. The permittivity of the nanocomposites increased linearly with the concentration of BT and reached 3.6 times that for pure SRM at 50 wt%. The elastic modulus and the viscosity remained almost constant up to 20 wt% and then decreased above this concentration. The actuation strain of a planar actuator using SRM and 50 wt% BT was four times larger than that of the DEA with pure SRM.

  18. Materials development

    International Nuclear Information System (INIS)

    Objective of the materials program is the development of a structural material for the MSBR primary circuit which is resistant to irradiation embrittlement and intergranular attack by fission products. The bulk of the work was done on the development and study of modified Hastelloy N (Ti, Nb), including its interaction with salt and fission Te. Materials (Ta-10 percent W, Mo, graphite) are also being tested for corrosion resistance at 600 and 7000C to Bi--Li for use in fuel processing

  19. Materials characterisation

    International Nuclear Information System (INIS)

    Various nuclear techniques have been developed and employed by technologies and scientists worldwide to physically and chemically characterise the material particularly those that have applications in industry. These include small angle neutron scattering (SANS), x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) for the internal structural study of material, whereas, the x-ray fluorescence (XRF) for the chemical analysis, while the Moessbauer spectroscopy for the study on the magnetic properties and structural identity of material. Basic principle and instrumentations of the techniques are discussed in this chapter. Example of their applications in various disciplines particularly in characterisation of industrial materials also described

  20. Composite material

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A. (Knoxville, TN); Woodward, Jonathan (Solihull, GB); Evans, Barbara R. (Oak Ridge, TN); O' Neill, Hugh M. (Knoxville, TN)

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  1. Composite material

    Science.gov (United States)

    Hutchens, Stacy A. (Knoxville, TN); Woodward, Jonathan (Solihull, GB); Evans, Barbara R. (Oak Ridge, TN); O'Neill, Hugh M. (Knoxville, TN)

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  2. Comparación de la resistencia al deslizamiento en brackets de autoligado y brackets convencionales ligados con ligadura elastomérica convencional y ligaduras de baja fricción / Comparison of resistance to sliding produced by self-ligating Brackets and conventional brackets ligated with conventional Elastomeric ligature and low-friction ligatures

    Scientific Electronic Library Online (English)

    Mileny, Nieto Uribe; Judith Patricia, Barrera Chaparro; Ernesto José, González Cáceres; Ivón Lilian, Parra Mazo; Aleida Cristina, Rodríguez Quijada.

    2012-06-01

    Full Text Available INTRODUCCIÓN: es importante para el ortodoncista conocer la resistencia al deslizamiento (RD) generada por el método de ligado usado durante la fase de cierre de espacio con mecánica de deslizamiento. El objetivo es comparar in vitro la RD de un tipo de bracket de autoligado con un tipo de bracket c [...] onvencional combinado con ligaduras elastoméricas de baja fricción y ligadura elastomérica convencional. MÉTODOS: se utilizaronbrackets de autoligado SmartClip (3M®) ybrackets convencionales Gemini (3M®), dos tipos de ligadura elastomérica de baja fricción Slide (Leone®), Synergy (RMO®) y un tipo de ligadura elastomérica convencional Sani-Tie (GAC®). Los sistemas de ligación de los brackets fueron probados con alambre de acero inoxidable calibre 0,019 × 0,025?. La resistencia al deslizamiento de la combinación bracket/alambre/ligadura fue medida con un modelo experimental de tres brackets cementados en una placa acrílica, montada en una máquina Instron. Cada combinación fue probada 9 veces consecutivas en estado seco. RESULTADOS: losbrackets Gemini (3M®) con ligadura convencional Sani-tie (GAC®), reportaron valores promedio de 67,3 g y los brackets Gemini (3M®) con ligadura de baja fricción siliconada Synergy (RMO®) de 84,6 g. Losbrackets SmartClip (3M®) y Gemini (3M®) con ligadura elastomérica de baja fricción Slide (Leone®) tuvieron valores promedio similares de 5,0 y 5,4 g, respectivamente, sin diferencias significativas (p = 0,999). CONCLUSIONES: las ligaduras elastoméricas de baja fricción Slide (Leone®), mostraron fuerzas de resistencia al deslizamiento similares a los brackets de autoligado Smartclip (3M®). Abstract in english INTRODUCTION: It is important for the orthodontist to be familiar with the sliding resistance (SR) generated by the ligation method used during the space closure phase with sliding mechanics. The objective of this article is to make an in vitro comparison of the SR produced by a self-ligating bracke [...] t and a conventional bracket in combination with low-friction and conventional elastomeric ligatures. METHODS:SmartClip (3M®) self-ligatingbrackets and Gemini (3M®) conventional brackets were used, as well as two types of low-friction elastomeric ligature: Slide (Leone®) and Synergy (RMO®), and one type of conventional elastomeric ligature: Sani-Tie (GAC®).The brackets ligation systems were tested with stainless steel wire of 0.019 × 0.025'' caliber. Sliding resistance of the bracketwire- ligature combination was measured with an experimental model of three brackets bonded in an acrylic plate mounted on an Instron machine. Each combination was tested nine consecutive times in dry state. RESULTS: The Gemini (3M®)brackets with a conventional Sani-Tie (GAC®) ligature reported mean values of 67.3 g, while the Gemini (3M®)brackets with low-friction Synergy (RMO®) silicone ligature obtained mean values of 84.6 g. The SmartClip (3M®) and Gemini (3M®)brackets with low-friction Slide (Leone®) elastomeric ligature had similar mean values of 5.0 and 5.4 g respectively, with no significant differences (p = 0.999). CONCLUSIONS: The Slide (Leone®) low-friction elastomeric ligatures showed sliding resistance forces similar to the SmartClip (3M®) self-ligatingbrackets.

  3. Comparación de la resistencia al deslizamiento en brackets de autoligado y brackets convencionales ligados con ligadura elastomérica convencional y ligaduras de baja fricción Comparison of resistance to sliding produced by self-ligating Brackets and conventional brackets ligated with conventional Elastomeric ligature and low-friction ligatures

    Directory of Open Access Journals (Sweden)

    Mileny Nieto Uribe

    2012-06-01

    Full Text Available INTRODUCCIÓN: es importante para el ortodoncista conocer la resistencia al deslizamiento (RD generada por el método de ligado usado durante la fase de cierre de espacio con mecánica de deslizamiento. El objetivo es comparar in vitro la RD de un tipo de bracket de autoligado con un tipo de bracket convencional combinado con ligaduras elastoméricas de baja fricción y ligadura elastomérica convencional. MÉTODOS: se utilizaronbrackets de autoligado SmartClip (3M® ybrackets convencionales Gemini (3M®, dos tipos de ligadura elastomérica de baja fricción Slide (Leone®, Synergy (RMO® y un tipo de ligadura elastomérica convencional Sani-Tie (GAC®. Los sistemas de ligación de los brackets fueron probados con alambre de acero inoxidable calibre 0,019 × 0,025?. La resistencia al deslizamiento de la combinación bracket/alambre/ligadura fue medida con un modelo experimental de tres brackets cementados en una placa acrílica, montada en una máquina Instron. Cada combinación fue probada 9 veces consecutivas en estado seco. RESULTADOS: losbrackets Gemini (3M® con ligadura convencional Sani-tie (GAC®, reportaron valores promedio de 67,3 g y los brackets Gemini (3M® con ligadura de baja fricción siliconada Synergy (RMO® de 84,6 g. Losbrackets SmartClip (3M® y Gemini (3M® con ligadura elastomérica de baja fricción Slide (Leone® tuvieron valores promedio similares de 5,0 y 5,4 g, respectivamente, sin diferencias significativas (p = 0,999. CONCLUSIONES: las ligaduras elastoméricas de baja fricción Slide (Leone®, mostraron fuerzas de resistencia al deslizamiento similares a los brackets de autoligado Smartclip (3M®.INTRODUCTION: It is important for the orthodontist to be familiar with the sliding resistance (SR generated by the ligation method used during the space closure phase with sliding mechanics. The objective of this article is to make an in vitro comparison of the SR produced by a self-ligating bracket and a conventional bracket in combination with low-friction and conventional elastomeric ligatures. METHODS:SmartClip (3M® self-ligatingbrackets and Gemini (3M® conventional brackets were used, as well as two types of low-friction elastomeric ligature: Slide (Leone® and Synergy (RMO®, and one type of conventional elastomeric ligature: Sani-Tie (GAC®.The brackets ligation systems were tested with stainless steel wire of 0.019 × 0.025'' caliber. Sliding resistance of the bracketwire- ligature combination was measured with an experimental model of three brackets bonded in an acrylic plate mounted on an Instron machine. Each combination was tested nine consecutive times in dry state. RESULTS: The Gemini (3M®brackets with a conventional Sani-Tie (GAC® ligature reported mean values of 67.3 g, while the Gemini (3M®brackets with low-friction Synergy (RMO® silicone ligature obtained mean values of 84.6 g. The SmartClip (3M® and Gemini (3M®brackets with low-friction Slide (Leone® elastomeric ligature had similar mean values of 5.0 and 5.4 g respectively, with no significant differences (p = 0.999. CONCLUSIONS: The Slide (Leone® low-friction elastomeric ligatures showed sliding resistance forces similar to the SmartClip (3M® self-ligatingbrackets.

  4. Thermoluminescent materials

    International Nuclear Information System (INIS)

    Thermoluminescence is the emission of light from substances when they are heated. This phenomena is observed for many synthetic and natural substances. These thermoluminescent materials must be ionic crystals, covalent crystals, and molecular crystals - an insulator or a semiconductor, but metals do not exhibit luminescent properties because they could not storage radiation energy. Most research has been devoted to the discovery and development of materials suitable for thermoluminescence dosemeters, and some phosphors are used routinely in dosimetric applications. But for other purposes, many interesting materials have been suggested and investigated. (author)

  5. BOOK REVIEW: NMR Imaging of Materials

    Science.gov (United States)

    Blümich, Bernhard

    2003-09-01

    Magnetic resonance imaging (MRI) of materials is a field of increasing importance. Applications extend from fundamental science like the characterization of fluid transport in porous rock, catalyst pellets and hemodialysers into various fields of engineering for process optimization and product quality control. While the results of MRI imaging are being appreciated by a growing community, the methods of imaging are far more diverse for materials applications than for medical imaging of human beings. Blümich has delivered the first book in this field. It was published in hardback three years ago and is now offered as a paperback for nearly half the price. The text provides an introduction to MRI imaging of materials covering solid-state NMR spectroscopy, imaging methods for liquid and solid samples, and unusual MRI in terms of specialized approaches to spatial resolution such as an MRI surface scanner. The book represents an excellent and thorough treatment which will help to grow research in materials MRI. Blümich developed the treatise over many years for his research students, graduates in chemistry, physics and engineering. But it may also be useful for medical students looking for a less formal discussion of solid-state NMR spectroscopy. The structure of this book is easy to perceive. The first three chapters cover an introduction, the fundamentals and methods of solid-state NMR spectroscopy. The book starts at the ground level where no previous knowledge about NMR is assumed. Chapter 4 discusses a wide variety of transformations beyond the Fourier transformation. In particular, the Hadamard transformation and the 'wavelet' transformation are missing from most related books. This chapter also includes a description of noise-correlation spectroscopy, which promises the imaging of large objects without the need for extremely powerful radio-frequency transmitters. Chapters 5 and 6 cover basic imaging methods. The following chapter about the use of relaxation and spectroscopic methods to weight or filter the spin signals represents the core of the book. This is a subject where Blümich is deeply involved with substantial contributions. The chapter includes a lot of ideas to provide MR contrast between different regions based on their mobility, diffusion, spin couplings or NMR spectra. After describing NMR imaging methods for solids with broad lines, Blümich spends time on applications in the last two chapters of the book. This part is really fun to read. It underlines the effort to bring NMR into many kinds of manufacturing. Car tyres and high-voltage cables are just two such areas. Elastomeric materials, green-state ceramics and food science represent other interesting fields of applications. This part of the book represents a personal but nevertheless extensive compilation of modern applications. As a matter of course the MOUSE is presented, a portable permanent-magnet based NMR developed by Blümich and his co-workers. Thus the book is not only of interest to NMR spectroscopists but also to people in material science and chemical engineering. The bibliography and indexing are excellent and may serve as an attractive reference source for NMR spectroscopists. The book is the first on the subject and likely to become the standard text for NMR imaging of materials as the books by Abragam, Slicher and Ernst et al are for NMR spectroscopy. The purchase of this beautiful book for people dealing with NMR spectroscopy or medical MRI is highly recommended. Ralf Ludwig

  6. Reference Materials

    Science.gov (United States)

    Merkus, Henk G.

    Reference materials for measurement of particle size and porosity may be used for calibration or qualification of instruments or for validation of operating procedures or operators. They cover a broad range of materials. On the one hand there are the certified reference materials, for which governmental institutes have certified one or more typical size or porosity values. Then, there is a large group of reference materials from commercial companies. And on the other hand there are typical products in a given line of industry, where size or porosity values come from the analysis laboratory itself or from some round-robin test in a group of industrial laboratories. Their regular application is essential for adequate quality control of particle size and porosity measurement, as required in e.g., ISO 17025 on quality management. In relation to this, some quality requirements for certification are presented.

  7. Basalt Materials

    International Science & Technology Center (ISTC)

    Physicochemical Studies of Basalt Materials and Ceramic Chromite-Niobate Composites for the Purpose of the Immobilization of Ecologically Hazardous Actinides and the Making of Protective Barriers for a Long-term Safe Storage of Radwastes.

  8. Efeito da amarração em Ortodontia, com ligaduras elastoméricas e de aço inoxidável, na saúde periodontal / Effects of orthodontic ligation-using elastomeric and stainless steel ligatures-on periodontal health

    Scientific Electronic Library Online (English)

    Clotilde Freitas, Rodrigues; Lígia de Araújo Ramos, Sales; Robert Willer Farinazzo, Vitral; Marcelo Reis, Fraga; Cátia Cardoso Abdo, Quintão.

    2011-02-01

    Full Text Available OBJETIVO: o presente estudo avaliou clinicamente as condições periodontais de um grupo teste e um grupo controle utilizando-se os seguintes três sistemas de indexação periodontal: índice de biofilme, índice de sangramento e profundidade de sondagem. MÉTODOS: o grupo teste foi composto por 20 indivíd [...] uos com média etária de 13,5 anos, submetido ao tratamento ortodôntico fixo, que recebeu duas formas de ligaduras: a elastomérica e a de aço inoxidável. Os resultados foram comparados entre si e com um grupo controle, sem tratamento ortodôntico, composto de 15 indivíduos com média etária de 15,3 anos. As mensurações foram realizadas previamente ao tratamento ortodôntico (T1) e seis meses após a colocação do aparelho ortodôntico fixo (T2); e, no grupo controle, após seis meses da mensuração inicial (T2). Ambos os grupos foram orientados quanto à higiene bucal, segundo a técnica de Bass, antes do início do tratamento. RESULTADOS E CONCLUSÕES: os resultados das análises das faces dentárias demonstraram um aumento estatisticamente significativo nos índices de biofilme (P=0,000), sangramento gengival (P=0,000) e profundidade de sondagem (P=0,000), quando T1 e T2 e os grupos foram comparados; entretanto, não foram encontradas diferenças estatisticamente significativas entre as ligaduras elastoméricas e de aço inoxidável na avaliação desses índices periodontais. Abstract in english OBJECTIVE: This study aimed to conduct a clinical evaluation of the periodontal conditions of a test group and a control group using three periodontal indexing systems, namely: dental biofilm index (DBI), bleeding index (BI) and pocket probing depth (PPD). METHODS: The test group consisted of 20 sub [...] jects with a mean age of 13.5 years undergoing fixed orthodontic treatment involving the use of two types of ligature: elastomeric ligature (EL) and stainless steel ligature (SSL). The results were compared with a control group without prior orthodontic treatment, comprising 15 subjects with a mean age of 15.3 years. The measurements were performed prior to orthodontic treatment (T1) and six months after placement of a fixed orthodontic appliance (T2); and in the control group, six months after the initial measurement (T2). Both groups were instructed about oral hygiene, according to the Bass technique, before treatment. RESULTS AND CONCLUSIONS: Dental surfaces showed a statistically significant increase in levels of biofilm (P=0.000), gingival bleeding (P=0.000) and probing depth (P=0.000). When the T1 and T2 groups were compared, however, no statistically significant differences were found between EL and SSL in terms of these periodontal indexes.

  9. Efeito da amarração em Ortodontia, com ligaduras elastoméricas e de aço inoxidável, na saúde periodontal Effects of orthodontic ligation-using elastomeric and stainless steel ligatures-on periodontal health

    Directory of Open Access Journals (Sweden)

    Clotilde Freitas Rodrigues

    2011-02-01

    Full Text Available OBJETIVO: o presente estudo avaliou clinicamente as condições periodontais de um grupo teste e um grupo controle utilizando-se os seguintes três sistemas de indexação periodontal: índice de biofilme, índice de sangramento e profundidade de sondagem. MÉTODOS: o grupo teste foi composto por 20 indivíduos com média etária de 13,5 anos, submetido ao tratamento ortodôntico fixo, que recebeu duas formas de ligaduras: a elastomérica e a de aço inoxidável. Os resultados foram comparados entre si e com um grupo controle, sem tratamento ortodôntico, composto de 15 indivíduos com média etária de 15,3 anos. As mensurações foram realizadas previamente ao tratamento ortodôntico (T1 e seis meses após a colocação do aparelho ortodôntico fixo (T2; e, no grupo controle, após seis meses da mensuração inicial (T2. Ambos os grupos foram orientados quanto à higiene bucal, segundo a técnica de Bass, antes do início do tratamento. RESULTADOS E CONCLUSÕES: os resultados das análises das faces dentárias demonstraram um aumento estatisticamente significativo nos índices de biofilme (P=0,000, sangramento gengival (P=0,000 e profundidade de sondagem (P=0,000, quando T1 e T2 e os grupos foram comparados; entretanto, não foram encontradas diferenças estatisticamente significativas entre as ligaduras elastoméricas e de aço inoxidável na avaliação desses índices periodontais.OBJECTIVE: This study aimed to conduct a clinical evaluation of the periodontal conditions of a test group and a control group using three periodontal indexing systems, namely: dental biofilm index (DBI, bleeding index (BI and pocket probing depth (PPD. METHODS: The test group consisted of 20 subjects with a mean age of 13.5 years undergoing fixed orthodontic treatment involving the use of two types of ligature: elastomeric ligature (EL and stainless steel ligature (SSL. The results were compared with a control group without prior orthodontic treatment, comprising 15 subjects with a mean age of 15.3 years. The measurements were performed prior to orthodontic treatment (T1 and six months after placement of a fixed orthodontic appliance (T2; and in the control group, six months after the initial measurement (T2. Both groups were instructed about oral hygiene, according to the Bass technique, before treatment. RESULTS AND CONCLUSIONS: Dental surfaces showed a statistically significant increase in levels of biofilm (P=0.000, gingival bleeding (P=0.000 and probing depth (P=0.000. When the T1 and T2 groups were compared, however, no statistically significant differences were found between EL and SSL in terms of these periodontal indexes.

  10. Resistant materials

    International Nuclear Information System (INIS)

    Thermally resistant materials comprise an elastomer, particulate iron oxide, and at least one other particulate additive selected from aluminium silicate and silicon carbide. The material may be in the form of a self-supporting element e.g. a bushing, grommet or sheet, or in the form of a coating, e.g. an electrically insulating coating for an electrical cable. The elastomer is preferably an addition-curing polydimethyl siloxane, which may be cured with Pt-based curing catalysts. (author)

  11. New materials

    International Nuclear Information System (INIS)

    This volume contains state-to-the-art lectures presented by distinguished scientists on important aspects of new materials covering diverse and varied aspects of the subject, such as: growth and characterization of ZnSe-based II-VI semiconductor quantum wells and superlattices for short wavelength semiconductor lasers; atomic layer and unit-cell layer growth of oxide superconductor thin films by laser molecular beam epitaxy; lattice engineering of ceramics for exploration of new high Tc superconductors; hydrogenated amorphous silicon, its alloys and their device applications; organic superconductors; occurrence of high-temperature ?-phase of AgI at room temperature in superionic AgI-Ag2O-MxOy glasses; gas sensor materials; diamond thin films; sol-gel technique for materials synthesis; computer applications to materials science and engineering; icosahedral quasicrystals; construction and functional properties of polymer/(liquid crystal) composite systems; novel method to prepare conducting polymer composites; membranes for gas separations; discontinuously reinforced metal matrix composites; tribological behaviour of new materials; development of carbon-carbon composites; ceramic composites by directed metal oxidation; biofunctional materials that initiate, excel and control the living body; and biomaterials host tissue interactions. (orig.)

  12. A two-phase hyperelastic-viscoplastic constitutive model for semi-crystalline polymers: application to polyethylene materials with a variable range of crystal fractions.

    Science.gov (United States)

    Abdul-Hameed, H; Messager, T; Ayoub, G; Zaïri, F; Naït-Abdelaziz, M; Qu, Z; Zaïri, F

    2014-09-01

    Polyethylene-based polymers as biomedical materials can contribute to a wide range of biomechanical applications. Therefore, it is important to identify, analyse, and predict with precision their mechanical behaviour. Polyethylene materials are semi-crystalline systems consisting of both amorphous and crystalline phases interacting in a rather complex manner. When the amorphous phase is in the rubbery state, the mechanical behaviour is strongly dependent on the crystal fraction, therefore leading to essentially thermoplastic or elastomeric responses. In this study, the finite deformation stress-strain response of polyethylene materials is modelled by considering these semi-crystalline polymers as two-phase heterogeneous media in order to provide insight into the role of crystalline and amorphous phases on the macro-behaviour and on the material deformation resistances, i.e. intermolecular and network resistances. A hyperelastic-viscoplastic model is developed in contemplation of representing the overall mechanical response of polyethylene materials under large deformation. An evolutionary optimization procedure based on a genetic algorithm is developed to identify the model parameters at different strain rates. The identification results show good agreement with experimental data, demonstrating the usefulness of the proposed approach: the constitutive model, with only one set of identified parameters, allows reproducing the stress-strain behaviour of polyethylene materials exhibiting a wide range of crystallinities, the crystal content becoming the only variable of the model. PMID:24973989

  13. Material science and new materials

    International Nuclear Information System (INIS)

    Comprehensive studies were made into the structure and properties of materials intended for nuclear and thermonuclear reactor applications. The influence of reactor irradiation on stainless steels, zirconium, vanadium and nickel base alloys. 44 refs., 50 figs., 23 tabs

  14. Double differential neutron scattering cross sections of materials for ultra high temperature reactors

    International Nuclear Information System (INIS)

    The five materials with the highest melting point are hafnium, tantalum, niobium and zirconium (ZrC) carbides and graphite (that sublimes). Graphite is the material of choice for very high temperature reactors (VHTR); ultra high temperature reactors (UHTR), like the thermal nuclear propulsion reactor NERVA use a dispersion of ZrC and UC in graphite as the material in the reactor core. Presently there are neither inelastic nor elastic double differential scattering data available that describe the thermalization process in ZrC. We therefore, calculated coherent elastic and incoherent inelastic cross sections for the ZrC crystal which has a face centered cubic (fcc) lattice. The phonon spectrum for the ZrC lattice was calculated with the computer code PHONON using the Hellman-Feynman forces computed with ab-initio methods [Jochyn, P.T., Parlinski, K., 2000. Ab initio lattice dynamics and elastic constants of ZrC. Eur. Phys. J. B 15, 265-268]. This phonon spectrum was then used to compute the S(?, ?, T) matrices for the inelastic scattering cross sections for C and Zr in the ZrC lattice using modified versions of the computer codes GASKET, HEXSCAT and NJOY. The results were applied to calculate, with the proper S(?, ?, T), criticality and reactivity coefficients of temperate of reactor systems containing ZrC and UC. For comparisons, these parameters were also calculated with approximations of S(?, ?, T), i.e. the gas or the graphite scattering kernels. Depending onite scattering kernels. Depending on the degree of thermalization, k eff is underestimated between 0.6% and 1%, and the values and the shape of the reactivity coefficients as a function of temperature change by substantial amounts

  15. Wear materials

    International Nuclear Information System (INIS)

    This paper describes a new liner designed for a copper ore crusher in Yugoslavia. The experience gained over the past ten years of operation at the Bor copper mines has shown that correct selection of wear material for crusher liners is critical to successful plant performance. With the new wear resistant liners, the crusher development program has increased the concentrator throughput from 8.0 to 9.6 million tons/year. The ultimate goal of the project is to identify the proper liner material that will extend liner life, reduce cyclic stress on major crusher components, and simplify crusher control and adjustment. This paper describes the various liners materials and the mechanisms of wear

  16. Hardfacing material

    Science.gov (United States)

    Branagan, Daniel J. (Iona, ID)

    2012-01-17

    A method of producing a hard metallic material by forming a mixture containing at least 55% iron and at least one of boron, carbon, silicon and phosphorus. The mixture is formed into an alloy and cooled to form a metallic material having a hardness of greater than about 9.2 GPa. The invention includes a method of forming a wire by combining a metal strip and a powder. The metal strip and the powder are rolled to form a wire containing at least 55% iron and from two to seven additional elements including at least one of C, Si and B. The invention also includes a method of forming a hardened surface on a substrate by processing a solid mass to form a powder, applying the powder to a surface to form a layer containing metallic glass, and converting the glass to a crystalline material having a nanocrystalline grain size.

  17. Layered materials

    Science.gov (United States)

    Johnson, David; Clarke, Simon; Wiley, John; Koumoto, Kunihito

    2014-06-01

    Layered compounds, materials with a large anisotropy to their bonding, electrical and/or magnetic properties, have been important in the development of solid state chemistry, physics and engineering applications. Layered materials were the initial test bed where chemists developed intercalation chemistry that evolved into the field of topochemical reactions where researchers are able to perform sequential steps to arrive at kinetically stable products that cannot be directly prepared by other approaches. Physicists have used layered compounds to discover and understand novel phenomena made more apparent through reduced dimensionality. The discovery of charge and spin density waves and more recently the remarkable discovery in condensed matter physics of the two-dimensional topological insulating state were discovered in two-dimensional materials. The understanding developed in two-dimensional materials enabled subsequent extension of these and other phenomena into three-dimensional materials. Layered compounds have also been used in many technologies as engineers and scientists used their unique properties to solve challenging technical problems (low temperature ion conduction for batteries, easy shear planes for lubrication in vacuum, edge decorated catalyst sites for catalytic removal of sulfur from oil, etc). The articles that are published in this issue provide an excellent overview of the spectrum of activities that are being pursued, as well as an introduction to some of the most established achievements in the field. Clusters of papers discussing thermoelectric properties, electronic structure and transport properties, growth of single two-dimensional layers, intercalation and more extensive topochemical reactions and the interleaving of two structures to form new materials highlight the breadth of current research in this area. These papers will hopefully serve as a useful guideline for the interested reader to different important aspects in this field and an overview of current areas of research interest.

  18. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  19. Photostrictive materials

    Science.gov (United States)

    Kundys, B.

    2015-03-01

    Light-matter interactions that lead to nonthermal changes in size of the sample constitute a photostrictive effect in many compounds. The photostriction phenomenon was observed in four main groups of materials, ferroelectrics, polar, and non-polar semiconductors, as well as in organic-based materials that are reviewed here. The key mechanisms of photostriction and its dependence on several parameters and perturbations are assessed. The major literature of the photostriction is surveyed, and the review ends with a summary of the proposed technical applications.

  20. Materials 1980

    International Nuclear Information System (INIS)

    Of the papers presented, three have been previously input to the data base and a separate abstract was prepared for one paper to be added to the data base. The paper abstracted concerns the design and fabrication of composite material blades for large wind turbines

  1. Electronic Materials

    Science.gov (United States)

    Foll, Helmut

    This is full course in Electronic Materials offered by Prof. Dr. Helmut Föll of the University of Kiel in Germany. The course cover in detail the following topics: conductors, dialectrics, magnetics, semiconductor devices, and semiconductor manufacturing process. This resource should be use used by people involved in electrical engineering and semiconductor manufacturing courses.

  2. Friction Material Composites Materials Perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2012-01-01

    Friction Material Composites is the first of the five volumes which strongly educates and updates engineers and other professionals in braking industries, research and test labs. It explains besides the formulation of design processes and its complete manufacturing input. This book gives an idea of mechanisms of friction and how to control them by designing .The book is  useful for designers  of automotive, rail and aero industries for designing the brake systems effectively with the integration of friction material composite design which is critical. It clearly  emphasizes the driving  safety and how serious designers should  select the design input. The significance of friction material component like brake pad or a liner as an integral part of the brake system of vehicles is explained. AFM pictures at nanolevel illustrate broadly the explanations given.

  3. Magnetocaloric materials

    Energy Technology Data Exchange (ETDEWEB)

    Jeppesen, Stinus

    2008-10-15

    New and improved magnetocaloric materials are one of the cornerstones in the development of room temperature magnetic refrigeration. Magnetic refrigeration has been used since the 1930ies in cryogenic applications, but has since the discovery of room temperature refrigerants received enormous attention. This Ph.D. work has been mainly concerned with developing a new technique to characterize the magnetocaloric effect (MCE) and using this technique in the investigations on new and improved magnetocaloric materials. For this purpose a novel differential scanning calorimeter (DSC) with applied magnetic fields was developed for measuring heat capacity as function of magnetic field. Measurements using the developed DSC demonstrate a very high sensitivity, fast measurements and good agreement with results obtained by other techniques. Furthermore, two material systems have been described in this work. Both systems take basis in the mixed-valence manganite system La{sub 1-x}Ca{sub x}MnO{sub 3} well known from research on colossal magnetoresistance (CMR). The mixed-valence manganite crystallizes in the perovskite structure of general formula ABO{sub 3}. The first material system is designed to investigate the influence of low level Cu doping on the B-site. Six different samples were prepared with over-stoichiometric compositions La{sub 0.67}Ca{sub 0.33}Mn{sub 1.05}Cu{sub x}O{sub 3}, x=0, 1, 2, 3, 4 and 5%. All compositions crystallized well in the same perovskite structure, but the morphology of the samples changed drastically with doping. Investigation on the magnetocaloric properties revealed that small levels of Cu up to around 3% could improve the magnetocaloric performance of the materials. Furthermore, Cu could be used to tune the temperature interval without deteriorating the MCE, which is a much desired characteristic for potential use in magnetic refrigerators. A less comprehensive part of the work has been concerned with the investigation of doping on the A-site in the structure. The possibility of substituting the lanthanum content of the material with a lanthanide mix (Ln) consisting of La, Ce, Nd and Pr was investigated due to the potential of making more cost-effective materials. Four samples with compositions (La{sub 1-x}Ln{sub x}){sub 0.67}Ca{sub 0.33}Mn{sub 1.05}O3 with x=0, 0.33, 0.67 and 1.00, were synthesized to investigate the effect on the magnetocaloric properties. It was found that the perovskite structure could be maintained even at the highest level of doping (x=1.00), and that the maximum magnetic entropy change, DELTAS{sub M}, quantifying the magnetocaloric effect was actually enhanced to an optimum at x=0.67. Furthermore, the relative cooling power (RCP) was calculated for this series, and it was demonstrated that RCP increases continuously with doping and reaches the highest value in the composition, where the entire lanthanum content has been replaced by the lanthanide mix. These observations make promise of compositions, which could be competitive both in terms of cost-effectiveness and MCE. The work on the latter materials have been disclosed in a US and UK patent application. (author)

  4. Energy Materials

    OpenAIRE

    Bruce, DW; O'Hare, D.; Walton, RI

    2011-01-01

    In an age of global industrialisation and population growth, the area of energy is one that is very much in the public consciousness. Fundamental scientific research is recognised as being crucial to delivering solutions to these issues, particularly to yield novel means of providing efficient, ideally recyclable, ways of converting, transporting and delivering energy. This volume considers a selection of the state-of-the-art materials that are being designed to meet some of the energy challe...

  5. Prosthesis Material

    Science.gov (United States)

    2004-01-01

    In this photograph, Amputee Amie Bradly uses a NASA-developed prosthesis to paint her fingernails. Derived from foam insulation technology used to protect the Space Shuttle External Tank from excessive heat, FAB/CAD, a subsidiary of the Harshberger Prosthetic and Orthotic Center, utilized the technology to replace the heavy, fragile plaster they used to produce master molds for prosthetics. The new material was lighter, cheaper and easier to manufacture than plaster, resulting in lower costs to the customer.

  6. Material Reseach

    Science.gov (United States)

    Workman, Gary L.; Rathz, Tom

    1996-01-01

    Containerless processing experiments in space and in ground-based facilities such as the Drop Tube Facility at Marshall Space Flight Center provide a unique capabilty to study materials processing phenomena without the influence of walls on nucleation processes. This research will further develop that capability by new experiments with immesible systems. Nucleation and undercooling phenomena will be monitored using infra-red temperature measurements.

  7. Thermoelectric Materials

    Science.gov (United States)

    Gao, Peng; Berkun, Isil; Schmidt, Robert D.; Luzenski, Matthew F.; Lu, Xu; Bordon Sarac, Patricia; Case, Eldon D.; Hogan, Timothy P.

    2014-06-01

    Mg2(Si,Sn) compounds are promising candidate low-cost, lightweight, nontoxic thermoelectric materials made from abundant elements and are suited for power generation applications in the intermediate temperature range of 600 K to 800 K. Knowledge on the transport and mechanical properties of Mg2(Si,Sn) compounds is essential to the design of Mg2(Si,Sn)-based thermoelectric devices. In this work, such materials were synthesized using the molten-salt sealing method and were powder processed, followed by pulsed electric sintering densification. A set of Mg2.08Si0.4- x Sn0.6Sb x (0 ? x ? 0.072) compounds were investigated, and a peak ZT of 1.50 was obtained at 716 K in Mg2.08Si0.364Sn0.6Sb0.036. The high ZT is attributed to a high electrical conductivity in these samples, possibly caused by a magnesium deficiency in the final product. The mechanical response of the material to stresses is a function of the elastic moduli. The temperature-dependent Young's modulus, shear modulus, bulk modulus, Poisson's ratio, acoustic wave speeds, and acoustic Debye temperature of the undoped Mg2(Si,Sn) compounds were measured using resonant ultrasound spectroscopy from 295 K to 603 K. In addition, the hardness and fracture toughness were measured at room temperature.

  8. FOREWORD: Materials metrology Materials metrology

    Science.gov (United States)

    Bennett, Seton; Valdés, Joaquin

    2010-04-01

    It seems that so much of modern life is defined by the materials we use. From aircraft to architecture, from cars to communications, from microelectronics to medicine, the development of new materials and the innovative application of existing ones have underpinned the technological advances that have transformed the way we live, work and play. Recognizing the need for a sound technical basis for drafting codes of practice and specifications for advanced materials, the governments of countries of the Economic Summit (G7) and the European Commission signed a Memorandum of Understanding in 1982 to establish the Versailles Project on Advanced Materials and Standards (VAMAS). This project supports international trade by enabling scientific collaboration as a precursor to the drafting of standards. The VAMAS participants recognized the importance of agreeing a reliable, universally accepted basis for the traceability of the measurements on which standards depend for their preparation and implementation. Seeing the need to involve the wider metrology community, VAMAS approached the Comité International des Poids et Mesures (CIPM). Following discussions with NMI Directors and a workshop at the BIPM in February 2005, the CIPM decided to establish an ad hoc Working Group on the metrology applicable to the measurement of material properties. The Working Group presented its conclusions to the CIPM in October 2007 and published its final report in 2008, leading to the signature of a Memorandum of Understanding between VAMAS and the BIPM. This MoU recognizes the work that is already going on in VAMAS as well as in the Consultative Committees of the CIPM and establishes a framework for an ongoing dialogue on issues of materials metrology. The question of what is meant by traceability in the metrology of the properties of materials is particularly vexed when the measurement results depend on a specified procedure. In these cases, confidence in results requires not only traceable calibration of the various instruments and standards used but also the reliable application of an accepted measurement procedure. Nowhere is this more evident than in the use of hardness scales, which are not directly traceable to the SI. This special issue of Metrologia includes a summary of the findings and conclusions of the Working Group and a further 14 papers covering the full range of properties of interest in science, engineering and standards making. It includes papers by authors at eight national measurement institutes and four other research centres. In addition to mechanical properties, there are papers addressing issues associated with the measurement of electromagnetic, acoustic and optical properties as well as those arising from the specific structural features of many new materials. As guest editors, we are extremely grateful to all the authors who have contributed to this special issue on the measurement of the properties of materials. We hope it will contribute to a wider appreciation of many of the associated issues and foster a growing understanding of the importance of ensuring that all such measurements are performed in accordance with accepted standards and procedures, with proper attention to the need to establish the traceability of the results. Only in this way can the performance, safety and fitness for purpose of products be guaranteed.

  9. Adhesion measurements on patterned elastomeric surfaces

    OpenAIRE

    Kroner, Elmar K.

    2011-01-01

    Seit Entdeckung der Oberflächenstruktur von Geckozehen haben Wissenschaftler versucht, diese wegen ihrer einzigartigen Hafteigenschaften zu kopieren. Kürzlich ist es gelungen, Haftsysteme mit ähnlich komplexen Strukturen zu entwickeln, die die Haftkräfte des Geckos sogar übertreffen. Aufgrund des wachsenden kommerziellen Interesses werden immer komplexere Strukturen hergestellt. Dabei werden jedoch fundamentale wissenschaftliche Prinzipien vernachlässigt: der Unterschied zwischen Effekt...

  10. Development of a re-brazeable containment system for special nuclear material storage and transport

    International Nuclear Information System (INIS)

    This report describes a novel means of closing and sealing small type B radioactive material transport packages for surface or air transport as governed by 10CFR71 or NUREG-0360 has been developed at Sandia National Laboratories (SNL). This method is a controlled brazing process that may be used to attach and seal a closure lid to a containment vessel and then remove it at a later time. The process may be performed multiple times without the need for special preparations of the braze joint. A number of advantages for utilization of this technique have been determined. A brazed seal has integrity at high temperatures for better protection in accident or abnormal environments. A properly designed joint has essentially the same strength as the parent metal. A closure that is brazed, therefore, will no longer be the anticipated point of failure for a broad range of accident environments. This technique will allow the containment vessel design to be optimized with a lighter, more uniform wall thickness throughout. Finally, with a well defined process for sealing, mechanical inspection, leak testing, and then reopening at a later time, automation of the process is relatively straightforward and the overall system should be as easy to use as one that utilizes elastomeric seals for containment

  11. Advanced materials for control of post-earthquake damage in bridges

    Science.gov (United States)

    Shrestha, Kshitij C.; Saiid Saiidi, M.; Cruz, Carlos A.

    2015-02-01

    This paper presents analytical modeling to study the seismic response of bridge systems with conventional and advanced details. For validation, a 33 m quarter-scale model of a four-span bridge incorporating innovative materials and details seismically tested on the shake tables at the University of Nevada, Reno was taken. The bridge specimen involved use of advanced materials and details to reduce damage at plastic hinges and minimize residual displacements. A three-dimensional, nonlinear model incorporating the response of the innovative materials was developed to study the bridge response using the finite-element software OpenSees. Existing finite-element formulations were used to capture the response of the advanced materials used in the bridge. The analytical model was found to be able to reproduce comparable bent displacements and bent shear forces within reasonable accuracy. The validated model was further used to study different types of bridges under suite of scaled bi-directional near-fault ground motions. Comparisons were made on behavior of five different bridge types, first conventional reinforced concrete bridge, second post-tensioned column bridge, third bridge with elastomeric rubber elements at the plastic hinge zone, fourth bridge with nickel–titanium superelastic shape memory alloy (SMA) reinforcing bar and fifth bridge with CuAlMn superelastic SMA reinforcing bar. Both the SMA used bridges also utilized engineered cementitious composite element at the plastic hinge zone. The results showed effectiveness of the innovative interventions on the bridges in providing excellent recentering capabilities with minimal damage to the columns.

  12. Construction material

    Science.gov (United States)

    Wagh, Arun S. (Orland Park, IL); Antink, Allison L. (Bolingbrook, IL)

    2008-07-22

    A structural material of a polystyrene base and the reaction product of the polystyrene base and a solid phosphate ceramic is applied as a slurry which includes one or more of a metal oxide or a metal hydroxide with a source of phosphate to produce a phosphate ceramic and a poly (acrylic acid or acrylate) or combinations or salts thereof and polystyrene or MgO applied to the polystyrene base and allowed to cure so that the dried aqueous slurry chemically bonds to the polystyrene base. A method is also disclosed of applying the slurry to the polystyrene base.

  13. Casting materials

    Science.gov (United States)

    Chaudhry, Anil R. (Xenia, OH); Dzugan, Robert (Cincinnati, OH); Harrington, Richard M. (Cincinnati, OH); Neece, Faurice D. (Lyndurst, OH); Singh, Nipendra P. (Pepper Pike, OH)

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  14. Composite Materials

    Science.gov (United States)

    Twin Cities Public Television, Inc.

    2008-01-01

    This is an activity (located on page 3 of PDF) about composites, materials made of 2 or more different components. Learners will be challenged to build the best mud bricks, one of the earliest examples of composites. From a supply of various building components, which the learners will examine for their different properties, they will build mud bricks, then dry them and put them through several tests. *Bricks must bake in the sun for 2-3 days prior to testing. Resource contains information about how this activity relates to carbon nanotubes and links to video, DragonflyTV Nano: Hockey Sticks.

  15. Energy materials

    CERN Document Server

    Bruce, Duncan W; Walton, Richard I

    2011-01-01

    In an age of global industrialisation and population growth, the area of energy is one that is very much in the public consciousness. Fundamental scientific research is recognised as being crucial to delivering solutions to these issues, particularly to yield novel means of providing efficient, ideally recyclable, ways of converting, transporting and delivering energy. This volume considers a selection of the state-of-the-art materials that are being designed to meet some of the energy challenges we face today. Topics are carefully chosen that show how the skill of the synthetic chemist can

  16. Functional materials

    International Nuclear Information System (INIS)

    Development of fabrication process of functional ceramic materials, evaluation of characteristics and experiments for understanding of irradiation behavior of ceramics were carried out for application of ceramics to the nuclear industry. The developed processes were the SiC surface coating technology with large area for improvement of wear resistance and corrosion resistance, the fabrication technology of SiC composites for excellent irradiation resistance, performance improvement technology of SiC fiber and nano-sized powder processing by combustion ignition and spray. Typical results were CVD SiC coating with diameter of 25cm and thickness of 100?m, highly dense SiC composite by F-CVI, heat-treating technology of SiC fiber using B4C power, and nano-sized powders of ODS-Cu, Li-based breeding materials, Ni-based metal powders with primary particle diameter of 20?50nm. Furthermore, test equipment, data productions and damage evaluations were performed to understand corrosion resistance and wear resistance of alumina, silicon carbide and silicon nitride under PWR or PHWR operation conditions. Experimental procedures and basic technologies for evaluation of irradiation behavior were also established. Additionally, highly reactive precursor powders were developed by various technologies and the powders were applied to the fabrication of 100 m long Ag/Bi-2223 multi-filamentary wires. High Tc magnets and fly wheel for energy storage were developed, as well

  17. Photographic materials

    International Nuclear Information System (INIS)

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. The film material is comprised of a base having at least one layer of a photographic silver halide emulsion and a yellow filter dye screening the emulsion from visible radiation. The silver halide emulsion contains 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The nature and properties of the yellow filter dye are described. When recording an X-ray image, the film is loaded into the camera under white safelight conditions from which light of wavelength shorter than 400 nm is excluded. The film is in contact with one or more phosphor screens capable when struck by X-rays of emitting ultraviolet radiation, the screens having a peak ultraviolet emission within the wavelength range of 250-380 nm. After X-ray exposure, the film is removed and developed. Two examples illustrating the invention are given. (U.K.)

  18. Photovoltaic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15

    The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication of high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These tools were combined with others to study the effect of defects on the performance of crystalline s

  19. Synthesis, characterization, and efficacy of antimicrobial chlorhexidine hexametaphosphate nanoparticles for applications in biomedical materials and consumer products

    Directory of Open Access Journals (Sweden)

    Barbour ME

    2013-09-01

    Full Text Available Michele E Barbour,1 Sarah E Maddocks,2 Natalie J Wood,1,3 Andrew M Collins3 1Oral Nanoscience, School of Oral and Dental Sciences, University of Bristol, Bristol, UK; 2Cardiff School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK; 3Bristol Centre for Functional Nanomaterials, University of Bristol, Bristol, UK Abstract: Chlorhexidine (CHX is an antimicrobial agent that is efficacious against gram-negative and -positive bacteria and yeasts. Its mechanism of action is based on cell membrane disruption and, as such, it does not promote the development of bacterial resistance, which is associated with the widespread use of antibiotics. In this manuscript, we report the development of novel antimicrobial nanoparticles (NPs based on a hexametaphosphate salt of CHX. These are synthesized by instantaneous reaction between equimolar aqueous solutions of CHX digluconate and sodium hexametaphosphate, under room temperature and pressure. The reaction results in a stable colloid composed of highly negatively charged NPs (?50 mV, of size 20-160 nm. The NPs adhere rapidly to specimens of glass, titanium, and an elastomeric wound dressing, in a dose-dependent manner. The functionalized materials exhibit a gradual leaching of soluble CHX over a period of at least 50 days. The NP colloid is efficacious against methicillin-resistant Staphylococcus aureus (MRSA and Pseudomonas aeruginosa in both planktonic and biofilm conditions. These NPs may find application in a range of biomedical and consumer materials. Keywords: MRSA, biomaterials, chlorhexidine, drug delivery, slow release

  20. Photographic materials

    International Nuclear Information System (INIS)

    Radiographic films based on silver halides are normally handled under red or orange safelights to prevent fogging due to their sensitivity to white light. The present invention relates to ultraviolet radiation sensitive material which can be handled under virtually white light without significant fogging. A photographic, chemically sensitised silver halide emulsion is described, containing 50-100 mole % of silver chloride, the higher the silver chloride content, the lower the visible light sensitivity. The remaining silver halide, if any, is silver bromide and/or silver iodide. The silver halide grains are grown in the presence of ammonia, an excess of chloride ions and tetraazaindene growth controller. Examples illustrating the invention are given. (U.K.)

  1. PREFACE: Superconducting materials Superconducting materials

    Science.gov (United States)

    Charfi Kaddour, Samia; Singleton, John; Haddad, Sonia

    2011-11-01

    The discovery of superconductivity in 1911 was a great milestone in condensed matter physics. This discovery has resulted in an enormous amount of research activity. Collaboration among chemists and physicists, as well as experimentalists and theoreticians has given rise to very rich physics with significant potential applications ranging from electric power transmission to quantum information. Several superconducting materials have been synthesized. Crucial progress was made in 1987 with the discovery of high temperature superconductivity in copper-based compounds (cuprates) which have revealed new fascinating properties. Innovative theoretical tools have been developed to understand the striking features of cuprates which have remained for three decades the 'blue-eyed boy' for researchers in superconductor physics. The history of superconducting materials has been notably marked by the discovery of other compounds, particularly organic superconductors which despite their low critical temperature continue to attract great interest regarding their exotic properties. Last but not least, the recent observation of superconductivity in iron-based materials (pnictides) has renewed hope in reaching room temperature superconductivity. However, despite intense worldwide studies, several features related to this phenomenon remain unveiled. One of the fundamental key questions is the mechanism by which superconductivity takes place. Superconductors continue to hide their 'secret garden'. The new trends in the physics of superconductivity have been one of the two basic topics of the International Conference on Conducting Materials (ICoCoM2010) held in Sousse,Tunisia on 3-7 November 2010 and organized by the Tunisian Physical Society. The conference was a nice opportunity to bring together participants from multidisciplinary domains in the physics of superconductivity. This special section contains papers submitted by participants who gave an oral contribution at ICoCoM2010 and by invited authors selected by the editor. We are grateful to IUPAP, ICTP and the European Office of Aerospace Research and Development, Air Force Office of Scientific Research, United States Air Force Laboratory. We would like to acknowledge the authors for their careful work, and finally we thank Dr L Smith the publisher of Journal of Physics: Condensed Matter for her patience and help. Superconducting materials contents Raman spectrum in the pseudogap phase of the underdoped cuprates: effect of phase coherence and the signature of the KT-type superconducting transitionTao Li and Haijun Liao Pressure effects on Dirac fermions in ?-(BEDT-TTF)2I3Takahiro Himura, Takao Morinari and Takami Tohyama Effect of Zn doping in hole-type 1111 phase (Pr, Sr)FeAsOXiao Lin, Chenyi Shen, Chen Lv, Jianjian Miao, Hao Tan, Guanghan Cao and Zhu-An Xu Superconductivity and ferromagnetism in EuFe2(As1 - xPx)2*Guanghan Cao, Shenggao Xu, Zhi Ren, Shuai Jiang, Chunmu Feng and Zhu'an Xu OInhomogeneous superconductivity in organic conductors: the role of disorder and magnetic fieldS Haddad, S Charfi-Kaddour and J-P Pouget

  2. Mechatronic systems and materials materials production technologies

    CERN Document Server

    Marcinkevicius, Andrejus Henrikas

    2010-01-01

    Mechatronics can be defined as being the synergistic integration of mechanical engineering with electronics and intelligent computer control in the manufacture of products and design of processes. Advanced engineering materials and related technologies increasingly rely upon multifunctional materials, materials resistant to extreme conditions and hybrid and multi-materials. The goal of this collection is to disseminate news of recent progress made in the area of mechatronic systems and materials production technologies, to discuss future development in mechatronics and materials science, to an

  3. Gas storage materials, including hydrogen storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Mohtadi, Rana F; Wicks, George G; Heung, Leung K; Nakamura, Kenji

    2014-11-25

    A material for the storage and release of gases comprises a plurality of hollow elements, each hollow element comprising a porous wall enclosing an interior cavity, the interior cavity including structures of a solid-state storage material. In particular examples, the storage material is a hydrogen storage material, such as a solid state hydride. An improved method for forming such materials includes the solution diffusion of a storage material solution through a porous wall of a hollow element into an interior cavity.

  4. Phthalates and food-contact materials: enforcing the 2008 European Union plastics legislation

    DEFF Research Database (Denmark)

    Petersen, Jens HØjslev; Jensen, Lisbeth Krüger

    2010-01-01

    The migration of phthalates into foodstuffs from food-contact materials (FCM) is a well-known source of food contamination. In 2005, the European Food Safety Authority finalized its risk assessment for several of the classical phthalate plasticizers. In their risk management procedure the European Commission transformed the tolerable daily intakes established by the Authority into legislative limits for phthalates in both plastic and food simulants, while taking exposure from other sources into consideration. These limits have been into force since 1 July 2008. A detailed interpretation of the regulation of these substances was agreed upon in the European network of FCM reference laboratories. This paper reports results from a Danish control campaign of samples collected by official food inspectors and analysed by a newly validated analytical method run under accreditation. Samples were from FCM producers, FCM importers and importers of packed foodstuffs from third-party countries. Products containing phthalates above the current limits were found in several categories of FCM: conveyor belts (six of six), lids from packed foodstuffs in glasses (eight of 28), tubes for liquid foodstuffs (four of five) and gloves (five of 14). More than 20% of the samples analysed contained dibutylphthalate (DBP) or di-(2-ethylhexyl)phthalate (DEHP) above the compositional limits of 0.05% and 0.1%, respectively. Analysis of residual phthalates in metal lid gaskets instead of analysis of phthalates in the food when controlling foodstuffs packed outside the European Union proved to be an efficient and simple control method. All findings of phthalates were associated with the use of plasticized polyvinylchloride (PVC).

  5. High temperature range recuperator. Phase II. Prototype demonstration and material and analytical studies. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-04-01

    A summary of the work performed to fully evaluate the commercial potential of a unique ceramic recuperator for use in recovering waste heat from high temperature furnace exhaust gases is presented. The recuperator concept being developed consists of a vertical cylindrical heat exchange column formed from modular sections. Within the column, the gasketed modules form two helical flow passages - one for high temperature exhaust gases and one for pre-heating combustion air. The column is operated in a counterflow mode, with the exhaust gas entering at the bottom and the combustion air entering at the top of the column. Activities included design and procurement of prototype recuperator modules, construction and testing of two prototype recuperator assemblies, exposure and mechanical properties testing of candidate materials, structural analysis of the modules, and assessment of the economic viability of the concept. The results of the project indicated that the proposed recuperator concept was feasible from a technical standpoint. Economic analysis based upon recuperator performance characteristics and module manufacturing costs defined during the program indicated that 3 to 10 years (depending upon pre-heat temperature) would be required to recover the capital cost of the system in combustion air preheat applications. At this stage in the development of the recuperator, many factors in the analysis had to be assumed. Significant changes in some of the assumptions could dramatically affect the economics. For example, utilizing $2.85 per mcf for the natural gas price (as opposed to $2.00 per mcf) could reduce the payback period by more than half in certain cases. In addition, future commercial application will depend upon ceramic component manufacturing technique advances and cost reduction.

  6. Nuclear materials in Japan

    Science.gov (United States)

    2015-03-01

    The incident at Fukushima Daiichi brought materials in the nuclear industry into the spotlight. Nature Materials talks to Tatsuo Shikama, Director of the International Research Centre for Nuclear Materials, Institute for Materials Research, Tohoku University, about the current situation.

  7. The materials physics companion

    CERN Document Server

    Fischer-Cripps, Anthony C

    2014-01-01

    Introduction to Materials Physics: Structure of matter. Solid state physics. Dynamic properties of solids. Dielectric Properties of Materials: Dielectric properties. Ferroelectric and piezoelectric materials. Dielectric breakdown. Applications of dielectrics. Magnetic Properties of Materials: Magnetic properties. Magnetic moment. Spontaneous magnetization. Superconductivity.

  8. Improvement and evaluation of thermal, electrical, sealing and mechanical contacts, and their interface materials

    Science.gov (United States)

    Luo, Xiangcheng

    Material contacts, including thermal, electrical, seating (fluid sealing and electromagnetic sealing) and mechanical (pressure) contacts, together with their interface materials, were, evaluated, and in some cases, improved beyond the state of the art. The evaluation involved the use of thermal, electrical and mechanical methods. For thermal contacts, this work evaluated and improved the heat transfer efficiency between two contacting components by developing various thermal interface pastes. Sodium silicate based thermal pastes (with boron nitride particles as the thermally conductive filler) as well as polyethylene glycol (PEG) based thermal pastes were developed and evaluated. The optimum volume fractions of BN in sodium silicate based pastes and PEG based pastes were 16% and 18% respectively. The contribution of Li+ ions to the thermal contact conductance in the PEG-based paste was confirmed. For electrical contacts, the relationship between the mechanical reliability and electrical reliability of solder/copper and silver-epoxy/copper joints was addressed. Mechanical pull-out testing was conducted on solder/copper and silver-epoxy/copper joints, while the contact electrical resistivity was measured. Cleansing of the copper surface was more effective for the reliability of silver-epoxy/copper joint than that of solder/copper joint. For sealing contacts, this work evaluated flexible graphite as an electromagnetic shielding gasket material. Flexible graphite was found to be at least comparable to conductive filled silicone (the state of the art) in terms of the shielding effectiveness. The conformability of flexible graphite with its mating metal surface under repeated compression was characterized by monitoring the contact electrical resistance, as the conformability is important to both electromagnetic scaling and fluid waling using flexible graphite. For mechanical contacts, this work focused on the correlation of the interface structure (such as elastic/plastic deformation, oxidation, strain hardening, passive layer damage, fracture, etc.) with the electrical contact resistance, which was measured in real time for contacts under dynamic compression, thus allowing both reversible and irreversible changes to be observed. The materials studied included metals (carbon steel, stainless steel, aluminum and copper), carbon fiber reinforced polymer-matrix composite (nylon-6), ceramic (mortar) and graphite, due to their relevance to fastening, concrete structures, electric brushes and electrical pressure contacts.

  9. Photorefractive Materials and Their Applications 2 Materials

    CERN Document Server

    Günter, Peter

    2007-01-01

    Photorefractive Materials and Their Applications 2: Materials is the second of three volumes within the Springer Series in Optical Sciences. The book gives a comprehensive review of the most important photorefractive materials and discusses the physical properties of organic and inorganic crystals as well as poled polymers. In this volume, photorefractive effects have been investigated at wavelengths covering the UV, visible and near infrared. Researchers in the field and graduate students of solid-state physics and engineering will gain a thorough understanding of the properties of materials in photorefractive applications. The other two volumes are: Photorefractive Materials and Their Applications 1: Basic Effects. Photorefractive Materials and Their Applications 3: Applications.

  10. High purity materials, standards, and reference materials

    International Nuclear Information System (INIS)

    The authors review the use of nondestructive neutron activation analysis for determining trace impurities in high purity materials. They then consider the use of standards and reference materials. (Auth.)

  11. Transporting particulate material

    Science.gov (United States)

    Aldred, Derek Leslie (North Hollywood, CA); Rader, Jeffrey A. (North Hollywood, CA); Saunders, Timothy W. (North Hollywood, CA)

    2011-08-30

    A material transporting system comprises a material transporting apparatus (100) including a material transporting apparatus hopper structure (200, 202), which comprises at least one rotary transporting apparatus; a stationary hub structure (900) constraining and assisting the at least one rotary transporting apparatus; an outlet duct configuration (700) configured to permit material to exit therefrom and comprising at least one diverging portion (702, 702'); an outlet abutment configuration (800) configured to direct material to the outlet duct configuration; an outlet valve assembly from the material transporting system venting the material transporting system; and a moving wall configuration in the material transporting apparatus capable of assisting the material transporting apparatus in transporting material in the material transporting system. Material can be moved from the material transporting apparatus hopper structure to the outlet duct configuration through the at least one rotary transporting apparatus, the outlet abutment configuration, and the outlet valve assembly.

  12. Transporting particulate material

    Energy Technology Data Exchange (ETDEWEB)

    Aldred, Derek Leslie (North Hollywood, CA); Rader, Jeffrey A. (North Hollywood, CA); Saunders, Timothy W. (North Hollywood, CA)

    2011-08-30

    A material transporting system comprises a material transporting apparatus (100) including a material transporting apparatus hopper structure (200, 202), which comprises at least one rotary transporting apparatus; a stationary hub structure (900) constraining and assisting the at least one rotary transporting apparatus; an outlet duct configuration (700) configured to permit material to exit therefrom and comprising at least one diverging portion (702, 702'); an outlet abutment configuration (800) configured to direct material to the outlet duct configuration; an outlet valve assembly from the material transporting system venting the material transporting system; and a moving wall configuration in the material transporting apparatus capable of assisting the material transporting apparatus in transporting material in the material transporting system. Material can be moved from the material transporting apparatus hopper structure to the outlet duct configuration through the at least one rotary transporting apparatus, the outlet abutment configuration, and the outlet valve assembly.

  13. Thermochromic and thermotropic materials

    CERN Document Server

    Seeboth, Arno

    2013-01-01

    Thermochromic materials based on reflectionThermochromic materials based on light absorptionThermochrmic and thermotropic materials based on light scatteringApplication of thermochromic and thermotropic materialsActive triggering and energetic characterization of thermotropic and of thermochromic materialsConcluding remarks. All chapters by Dr. Arno Seeboth and Dr. Detlef Lötzsch

  14. Computational materials design

    International Nuclear Information System (INIS)

    The concept of computational materials design is explained and the applications to the diluted magnetic semiconductors are discussed. The computational materials design is a system composed of three ingredients, namely the materials simulation, the discovery of mechanisms, and the guess for a new material. These three are combined to each other as a system, forming materials design engine. (author)

  15. 46 CFR 151.20-1 - Piping-general.

    Science.gov (United States)

    2010-10-01

    ...chapter. The valve seat material, packing, gaskets, and all other material which comes into contact...with corrosion-resistant material. Vent systems shall be...weatherdeck. There shall be cargo compatibility in the event of a...

  16. Immobilization of waste material

    International Nuclear Information System (INIS)

    A method is described for immobilizing or solidifying waste material, which includes blending the waste material with powdered metal and subjecting the mixture of waste material and powdered metal to high pressure. (author)

  17. Super Dielectric Materials

    OpenAIRE

    Fromille, Sam; Phillips, Jonathan

    2014-01-01

    Evidence is provided that a class of materials with dielectric constants greater than 100,000, herein called super dielectric materials (SDM), can be generated readily from common, inexpensive materials.

  18. Thermoelectric materials and devices

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Talcott, Noel A. (Inventor)

    2011-01-01

    New thermoelectric materials comprise highly [111]-oriented twinned group IV alloys on the basal plane of trigonal substrates, which exhibit a high thermoelectric figure of merit and good material performance, and devices made with these materials.

  19. Environmental Risk Assessment of the Olefin plant in Arya Sasol Petrochemical Complex using Fault Tree Analysis Method

    Directory of Open Access Journals (Sweden)

    S. A. Jozi

    2015-05-01

    Conclusion: Most likely occurrence of the final event was related to the gasket unsuitable material (2×10-2. Control action to prevent the occurrence of leakage could be supplying high quality gaskets and the failure is classified in the hardware failure category.

  20. Materials for Fusion Applications

    OpenAIRE

    Jioí Mat?jí?ek

    2013-01-01

    An overview of materials foreseen for use or already used in fusion devices is given. The operating conditions, material requirements and characteristics of candidate materials in several specific application segments are briefly reviewed. These include: construction materials, electrical insulation, permeation barriers and plasma facing components. Special attention will be paid to the latter and to the issues of plasma-material interaction, materials joining and fuctionally graded interlayers.

  1. Common Waste and Materials

    Science.gov (United States)

    ... Home Wastes Resource Conservation Common Wastes & Materials Common Waste and Materials Related Links Universal Waste Comprehensive Procurement Guidelines (CPG) Environmentally Preferable Purchasing (EPP) ...

  2. Fusion materials: insulators and plasma facing materials

    International Nuclear Information System (INIS)

    Insulating materials: surface damage: Oxide materials will be extensively used in ITER in heating and current drive, and diagnostic systems where they will play important roles as electrical insulators, and RF and optical transmission components. These materials will be subjected to neutron and gamma radiation, and additionally to bombardment by low energy ions and neutral particles of energies between eV and keV as a consequence of neutron reactions and related sputtering at vacuum surfaces, as well as ionization and acceleration of the residual gas due to local electric fields. To assess the damage, SiO2 (KS-4V), Al2O3, AlN, and BeO, the main candidate ceramic insulators for ITER were implanted (bombarded) with light ions, and KS-4V and sapphire were also irradiated with electrons. In-situ surface electrical conductivity measurements in high vacuum during implantation or irradiation were carried out. In addition, before and after implantation or irradiation, both optical absorption measurements and SEM X-ray analysis were performed. It was found that the origin of the surface electrical and related optical degradation is radiolytic, i.e. the damage is caused by the electronic excitation induced during material irradiation. Plasma Wall Interaction: In fusion devices, in the region next to high temperature plasma (typically ?10 keV), material erodes from plasma-facing materials in one location and is transported to other, sometimes remote, locations throughout the device. The transported material may then be deposited on, or implanted into, other materials. If the plasma facing material in a device consists of more than a single element there is a high probability that the composition of the plasma-facing surfaces will evolve over time and may exhibit plasma interaction properties much different from the originally installed material. These plasma-created materials are so - called mixed materials. The creation of mixed-material surfaces will depend on many factors that determine the arrival and loss rate of material from those surfaces. Previous works carried out in the linear divertor plasma simulator PISCES-B on beryllium/carbon mixed-material effects revealed that both chemical and physical erosion of carbon was mitigated by beryllium impurities in the plasma. X-ray photoelectron spectroscopy (XPS) analyses of these targets subsequent to plasma exposure revealed the formation of beryllium carbide (Be2C), which is thought to play an important role in carbon erosion mitigation. Here, formation and evolution of mixed material in JET, in where both beryllium and carbon are used together as plasma-facing materials are discussed. (author)

  3. Physically Functional Materials

    DEFF Research Database (Denmark)

    Berg, Rolf Henrik Technical University of Denmark,

    The invention relates to novel monodisperse or polydisperse compounds, in general named DNO (diamino acid Nalpha-substituted oligopeptides), preferably low molecular weight polypeptides, e.g., based on ornithine, lysine, diaminobutyric acid, diaminopropionic acid, aminoethylglycine or other amino acids or peptides having azobenzenes or other physicially functional groups, e.g., photoresponsive groups, as side chains. These compounds may be synthesized using solid phase peptide synthesis techniques. Materials, e.g., thin films, comprising such compounds may be used for optical storage of information (holographic data storage), nonlinear optics (NLO), as photoconductors, photonic band-gap materials, electrically conducting materials, electroluminescent materials, piezo-electric materials, pyroelectric materials, magnetic materials, ferromagnetic materials, ferroelectric materials, photorefractive materials, or materials in which light-induced conformational changes can be produced. Optical anisotropy may reversibly be generated with polarized laser light whereby a hologram is formed. First order diffraction efficiencies of up to around 80% have been obtained.

  4. Novel Ternary Molten Salt Electrolytes for intermediate-temperature sodium/nickel chloride batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guosheng; Lu, Xiaochuan; Coyle, Christopher A.; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2012-12-15

    The sodium-nickel chloride (ZEBRA) battery is typically operated at relatively high temperature (250~350°C) to achieve adequate electrochemical performance. Reducing the operating temperature in the range of 150 to 200°C can lead to enhanced cycle life by suppressing temperature related degradation mechanisms. The reduced temperature range also allows for lower cost materials of construction such as elastomeric sealants and gaskets. To achieve adequate electrochemical performance at lower operating temperatures requires an overall reduction in ohmic losses associated with temperature. This includes reducing the ohmic resistance of ?”-alumina solid electrolyte (BASE) and the incorporation of low melting point molten salt as the secondary electrolyte. In present work, planar-type Na/NiCl2 cells with a thin flat plate BASE (600 ?m) and low melting point secondary electrolyte were evaluated at reduced temperatures. Molten salt formulation for use as secondary electrolytes were fabricated by the partial replace of NaCl in the standard secondary electrolyte (NaAlCl4) with other lower melting point alkali metal salts such as NaBr, LiCl, and LiBr. Electrochemical characterization of the ternary molten salts demonstrated , improved ionic conductivity, and sufficient electrochemical window at reduced temperatures. Furthermore, Na/NiCl2 cells with 50 mol% NaBr-containing secondary electrolyte exhibited reduced polarizations at 175°C compared to the cell with the standard NaAlCl4 catholyte. The cells also exhibited stable cycling performance even at 150oC.

  5. Insulation Materials Investigation

    Science.gov (United States)

    National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

    Students test the insulation properties of different materials by timing how long it takes ice cubes to melt in the presence of various insulating materials. Students learn about the role that thermal insulation materials can play in reducing heat transfer by conduction, convection and radiation, as well as the design and implementation of insulating materials in construction and engineering.

  6. Art as material culture

    OpenAIRE

    Den Berg, Dirk Johannes

    2001-01-01

    With questions concerning the physical basis and the material substructure of works of art as topic, the article surveys a number of related problem areas. These include the objecthood of art, art products as physical remnants, the situatedness and reproduction of art, materials expertise and the iconology of materials. The untenability of materialism features implicitly as an underlying theme.

  7. Tritium breeding materials

    International Nuclear Information System (INIS)

    Tritium breeding materials are essential to the operation of D-T fusion facilities. Both of the present options - solid ceramic breeding materials and liquid metal materials are reviewed with emphasis not only on their attractive features but also on critical materials issues which must be resolved

  8. Final evaluation report for a U.S. Department of Transportation Specification 7A Type A Radioactive Material Packaging, Lockheed Idaho Technologies Company (LITCO), Mark III Concrete Container, Docket 92-33-7A

    International Nuclear Information System (INIS)

    This report documents the U.S. Department of Transportation Specification 7A Type A (DOT-7A) compliance test results of the Mark III Concrete Container. The authorized configuration consists of the Mark III Concrete Container with a two-piece, welded, polyethylene liner (lid and body), polyethylene foam gasket, and six coil bolts and washers. A vent plug exists in the lid of the container. Two plugs are located on the side of the container body (lower portion), and allow the access to a ball valve. Two plugs are located underneath the bottom of the container body, near these side plugs. To drain the box, the bottom plugs need to be removed. The side plugs are then removed, allowing access to the ball valve. When the ball valve is opened, drainage occurs through the bottom drain area. After drainage, no residual liquid is permitted. The packaging may be used with or without the top wooden impact limiter. This packaging was evaluated and tested in August and October 1994. The packaging configurations described in this report are designed to ship Type A quantities of solid radioactive materials, Form No. 1, Form No. 2, and Form No. 3

  9. Side-chain Liquid Crystal Polymers (SCLCP: Methods and Materials. An Overview

    Directory of Open Access Journals (Sweden)

    W?odzimierz Sta?czyk

    2009-03-01

    Full Text Available This review focuses on recent developments in the chemistry of side chain liquid crystal polymers. It concentrates on current trends in synthetic methods and novel, well defined structures, supramolecular arrangements, properties, and applications. The review covers literature published in this century, apart from some areas, such as dendritic and elastomeric systems, which have been recently reviewed.

  10. Biological materials by design

    International Nuclear Information System (INIS)

    In this topical review we discuss recent advances in the use of physical insight into the way biological materials function, to design novel engineered materials ‘from scratch’, or from the level of fundamental building blocks upwards and by using computational multiscale methods that link chemistry to material function. We present studies that connect advances in multiscale hierarchical material structuring with material synthesis and testing, review case studies of wood and other biological materials, and illustrate how engineered fiber composites and bulk materials are designed, modeled, and then synthesized and tested experimentally. The integration of experiment and simulation in multiscale design opens new avenues to explore the physics of materials from a fundamental perspective, and using complementary strengths from models and empirical techniques. Recent developments in this field illustrate a new paradigm by which complex material functionality is achieved through hierarchical structuring in spite of simple material constituents. (topical review)

  11. Biological materials by design.

    Science.gov (United States)

    Qin, Zhao; Dimas, Leon; Adler, David; Bratzel, Graham; Buehler, Markus J

    2014-02-19

    In this topical review we discuss recent advances in the use of physical insight into the way biological materials function, to design novel engineered materials 'from scratch', or from the level of fundamental building blocks upwards and by using computational multiscale methods that link chemistry to material function. We present studies that connect advances in multiscale hierarchical material structuring with material synthesis and testing, review case studies of wood and other biological materials, and illustrate how engineered fiber composites and bulk materials are designed, modeled, and then synthesized and tested experimentally. The integration of experiment and simulation in multiscale design opens new avenues to explore the physics of materials from a fundamental perspective, and using complementary strengths from models and empirical techniques. Recent developments in this field illustrate a new paradigm by which complex material functionality is achieved through hierarchical structuring in spite of simple material constituents. PMID:24451343

  12. MRI-based morphological modeling, synthesis and characterization of cardiac tissue-mimicking materials

    International Nuclear Information System (INIS)

    This study uses standard synthetic methodologies to produce tissue-mimicking materials that match the morphology and emulate the in vivo murine and human cardiac mechanical and imaging characteristics, with dynamic mechanical analysis, atomic force microscopy (AFM), scanning electron microscopy (SEM) and magnetic resonance imaging. In accordance with such aims, poly(glycerol sebacate) (PGS) elastomeric materials were synthesized (at two different glycerol (G)–sebacic (S) acid molar ratios; the first was synthesized using a G:S molar ratio of 2:2, while the second from a 2:5 G:S molar ratio, resulting in PGS2:2 and PGS2:5 elastomers, respectively). Unlike the synthesized PGS2:2 elastomers, the PGS2:5 materials were characterized by an overall mechanical instability in their loading behavior under the three successive loading conditions tested. An oscillatory response in the mechanical properties of the synthesized elastomers was observed throughout the loading cycles, with measured increased storage modulus values at the first loading cycle, stabilizing to lower values at subsequent cycles. These elastomers were characterized at 4 °C and were found to have storage modulus values of 850 and 1430 kPa at the third loading cycle, respectively, in agreement with previously reported values of the rat and human myocardium. SEM of surface topology indicated minor degradation of synthesized materials at 10 and 20 d post-immersion in the PBS buffer solution, with a noted clus PBS buffer solution, with a noted cluster formation on the PGS2:5 elastomers. AFM nanoindentation experiments were also conducted for the measurement of the Young modulus of the sample surface (no bulk contribution). Correspondingly, the PGS2:2 elastomer indicated significantly decreased surface Young's modulus values 20 d post-PBS immersion, compared to dry conditions (Young's modulus = 1160 ± 290 kPa (dry) and 200 ± 120 kPa (20 d)). In addition to the two-dimensional (2D) elastomers, an integrative platform for accurate construction of three-dimensional tissue-mimicking models of cardiac anatomy from 2D MR images using rapid prototyping manufacturing processes was developed. For synthesized elastomers, doping strategies with two different concentrations of the MRI contrast agent Dotarem allowed independent and concurrent control of the imaging characteristics (contrast and relaxivity) during the synthetic process for increased contrast agent absorption, with tremendous potential for non-destructive in vivo use and applications to cardiovascular and cerebrovascular diseases. (paper)

  13. MRI-based morphological modeling, synthesis and characterization of cardiac tissue-mimicking materials.

    Science.gov (United States)

    Kossivas, Fotis; Angeli, S; Kafouris, D; Patrickios, C S; Tzagarakis, V; Constantinides, C

    2012-06-01

    This study uses standard synthetic methodologies to produce tissue-mimicking materials that match the morphology and emulate the in vivo murine and human cardiac mechanical and imaging characteristics, with dynamic mechanical analysis, atomic force microscopy (AFM), scanning electron microscopy (SEM) and magnetic resonance imaging. In accordance with such aims, poly(glycerol sebacate) (PGS) elastomeric materials were synthesized (at two different glycerol (G)-sebacic (S) acid molar ratios; the first was synthesized using a G:S molar ratio of 2:2, while the second from a 2:5 G:S molar ratio, resulting in PGS2:2 and PGS2:5 elastomers, respectively). Unlike the synthesized PGS2:2 elastomers, the PGS2:5 materials were characterized by an overall mechanical instability in their loading behavior under the three successive loading conditions tested. An oscillatory response in the mechanical properties of the synthesized elastomers was observed throughout the loading cycles, with measured increased storage modulus values at the first loading cycle, stabilizing to lower values at subsequent cycles. These elastomers were characterized at 4 °C and were found to have storage modulus values of 850 and 1430 kPa at the third loading cycle, respectively, in agreement with previously reported values of the rat and human myocardium. SEM of surface topology indicated minor degradation of synthesized materials at 10 and 20 d post-immersion in the PBS buffer solution, with a noted cluster formation on the PGS2:5 elastomers. AFM nanoindentation experiments were also conducted for the measurement of the Young modulus of the sample surface (no bulk contribution). Correspondingly, the PGS2:2 elastomer indicated significantly decreased surface Young's modulus values 20 d post-PBS immersion, compared to dry conditions (Young's modulus = 1160 ± 290 kPa (dry) and 200 ± 120 kPa (20 d)). In addition to the two-dimensional (2D) elastomers, an integrative platform for accurate construction of three-dimensional tissue-mimicking models of cardiac anatomy from 2D MR images using rapid prototyping manufacturing processes was developed. For synthesized elastomers, doping strategies with two different concentrations of the MRI contrast agent Dotarem allowed independent and concurrent control of the imaging characteristics (contrast and relaxivity) during the synthetic process for increased contrast agent absorption, with tremendous potential for non-destructive in vivo use and applications to cardiovascular and cerebrovascular diseases. PMID:22406555

  14. Orbital foamed material extruder

    Science.gov (United States)

    Tucker, Dennis S. (Inventor)

    2009-01-01

    This invention is a process for producing foamed material in space comprising the steps of: rotating the material to simulate the force of gravity; heating the rotating material until it is molten; extruding the rotating, molten material; injecting gas into the extruded, rotating, molten material to produce molten foamed material; allowing the molten foamed material to cool to below melting temperature to produce the foamed material. The surface of the extruded foam may be heated to above melting temperature and allowed to cool to below melting temperature. The extruded foam may also be cut to predetermined length. The starting material may be metal or glass. Heating may be accomplished by electrical heating elements or by solar heating.

  15. Composite Materials Handbook

    Science.gov (United States)

    From the US Army Research Laboratory, Materials Sciences Corporation, and University of Delaware Center for Composite Materials, the Composite Materials Handbook provides the "information and guidance necessary to design and fabricate end items from composite materials." Along with current information on the material properties of these composite materials, the handbook also includes data development and usage guidelines. The information has been divided into three areas: polymer, metal, and ceramic matrix composites. The Polymer Matrix Composites Handbook (three volumes including Guidelines for Characterization of Structural Materials; Material Properties; and Materials Usage, Design, and Analysis) and the Metal Matrix Composites Handbook (one volume, .pdf) are available here. The Ceramic Matrix Composites Handbook has yet to be completed. Users may also download Quick Composites Data in spreadsheet format.

  16. Joining of dissimilar materials

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Michael C; Lau, Grace Y; Jacobson, Craig P

    2012-10-16

    A method of joining dissimilar materials having different ductility, involves two principal steps: Decoration of the more ductile material's surface with particles of a less ductile material to produce a composite; and, sinter-bonding the composite produced to a joining member of a less ductile material. The joining method is suitable for joining dissimilar materials that are chemically inert towards each other (e.g., metal and ceramic), while resulting in a strong bond with a sharp interface between the two materials. The joining materials may differ greatly in form or particle size. The method is applicable to various types of materials including ceramic, metal, glass, glass-ceramic, polymer, cermet, semiconductor, etc., and the materials can be in various geometrical forms, such as powders, fibers, or bulk bodies (foil, wire, plate, etc.). Composites and devices with a decorated/sintered interface are also provided.

  17. NDT Supplemental Course Material

    Science.gov (United States)

    The NDT educational materials at the following links were developed primarily for college students: 1) to aid in conceptual learning, 2) to re-enforce materials provided at the student's school, and 3) to serve as reference materials and working tools. The materials are not intended to be a stand alone course in NDT but rather to supplement materials currently used in college NDT programs. The materials contain some interactive Flash and Java applets which help illustrate important concepts and can be used as NDT calculators. While the target audience in college students, NDT professionals may find the information interesting as useful as well.

  18. Materials science and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.

    1997-02-01

    During FY-96, work within the Materials Science and Engineering Thrust Area was focused on material modeling. Our motivation for this work is to develop the capability to study the structural response of materials as well as material processing. These capabilities have been applied to a broad range of problems, in support of many programs at Lawrence Livermore National Laboratory. These studies are described in (1) Strength and Fracture Toughness of Material Interfaces; (2) Damage Evolution in Fiber Composite Materials; (3) Flashlamp Envelope Optical Properties and Failure Analysis; (4) Synthesis and Processing of Nanocrystalline Hydroxyapatite; and (5) Room Temperature Creep Compliance of Bulk Kel-E.

  19. EC Transmission Line Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, Tim S [ORNL

    2012-05-01

    The purpose of this document is to identify materials acceptable for use in the US ITER Project Office (USIPO)-supplied components for the ITER Electron cyclotron Heating and Current Drive (ECH&CD) transmission lines (TL), PBS-52. The source of material property information for design analysis shall be either the applicable structural code or the ITER Material Properties Handbook. In the case of conflict, the ITER Material Properties Handbook shall take precedence. Materials selection, and use, shall follow the guidelines established in the Materials Assessment Report (MAR). Materials exposed to vacuum shall conform to the ITER Vacuum Handbook. [Ref. 2] Commercial materials shall conform to the applicable standard (e.g., ASTM, JIS, DIN) for the definition of their grade, physical, chemical and electrical properties and related testing. All materials for which a suitable certification from the supplier is not available shall be tested to determine the relevant properties, as part of the procurement. A complete traceability of all the materials including welding materials shall be provided. Halogenated materials (example: insulating materials) shall be forbidden in areas served by the detritiation systems. Exceptions must be approved by the Tritium System and Safety Section Responsible Officers.

  20. Nuclear Materials Storage

    International Science & Technology Center (ISTC)

    Creation of System for Storage, Operative Control and Physical Protection of Nuclear Materials and Ampoule Sources of Ionizing Radiation (ASIR) on "Baikal-1" stand Complex Meeting the International Requirements of Radioactive Materials Control...

  1. Hazardous Materials Incidents

    Science.gov (United States)

    ... chemical accidents in plants. Before Before a Hazardous Materials Incident Many communities have Local Emergency Planning Committees ( ... case of an emergency. During During a Hazardous Materials Incident Listen to local radio or television stations ...

  2. Practical materials characterization

    CERN Document Server

    2014-01-01

    Presents cross-comparison between materials characterization techniquesIncludes clear specifications of strengths and limitations of each technique for specific materials characterization problemFocuses on applications and clear data interpretation without extensive mathematics

  3. Nanostructured composite reinforced material

    Science.gov (United States)

    Seals, Roland D. (Oak Ridge, TN); Ripley, Edward B. (Knoxville, TN); Ludtka, Gerard M. (Oak Ridge, TN)

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  4. Smart hydrogel functional materials

    CERN Document Server

    CHU, Liang-Yin; Ju, Xiao-Jie; Wang, Wei

    2013-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  5. Advanced functional materials

    CERN Document Server

    2011-01-01

    This book reviews the results of recent research on new materials arising from progress in polymer, ceramic, sensor, and fuel cell technology, including advanced inorganic-organic-hybrid polymeric materials, high functional sensor, and microbial fuel cells.

  6. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  7. Informing material specification

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Karmon, Ayelet

    2012-01-01

    Architecture is entering a radical rethinking of its material practice. Advancements in material science and more complex models of material simulation as well as the interfaces between design and fabrication are fundamentally changing the way we conceive and design our built environment. This new technological platform allows an unprecedented control over the material. Creating direct links between the space of design and the space of fabrication, the idea of the hyper specified material developed in direct response to defined design criteria calls upon a new material practice in which designers of artifacts are also designers of materials. In this practice materials are seen as bespoke composites, differentiated and graded, and whose particular detailing is a central part of a projects overall solution. This paper will present a dual investigation into material design as an architectural practice. Taking point of departure in two cross disciplinary workshop investigations, we explore ways in which materially embedded sensing can lead to the making of new strategies for material design. Both investigations use textiles as a model for material thinking. Developing bespoke interfaces between programmable architectural design tools and advanced computer numerically controlled (CNC) knitting machines we understand the practice of textile design as a particular class of material design that enables variegation across both material and structure. Our aim for the experiments is firstly: the design of active materials that use integrated sensing as a means for triggering actuation and secondly: the design of graded materials that use integrated sensing as a means for specification. In the following we will discuss how these two practices can be interlinked, what are the shared concepts and technologies and can these be advantageously merged.

  8. Superconductivity in Actinide Materials

    OpenAIRE

    Thompson, J. D.; Sarrao, J. L.; Curro, N. J.; Bauer, E. D.; Morales, L. A.; Wastin, F.; Rebizant, J.; Griveau, J. C.; Boulet, P.; Colineau, E.; Lander, G. H.

    2005-01-01

    Actinide materials play a special role in condensed matter physics, spanning behaviours of itinerant d-electron and localized 4f-electron materials. An intermediate state, found notably in Pu-based materials whose 5f electrons are neither fully localized nor itinerant, is particularly challenging to understand. Superconductivity appearing in some actinide materials provides clues to the nature of the 5f electrons. PuCoGa5, the first Pu-based superconductor, is superconductin...

  9. Machinability of advanced materials

    CERN Document Server

    Davim, J Paulo

    2014-01-01

    Machinability of Advanced Materials addresses the level of difficulty involved in machining a material, or multiple materials, with the appropriate tooling and cutting parameters.  A variety of factors determine a material's machinability, including tool life rate, cutting forces and power consumption, surface integrity, limiting rate of metal removal, and chip shape. These topics, among others, and multiple examples comprise this research resource for engineering students, academics, and practitioners.

  10. Analysis of irradiated materials

    International Nuclear Information System (INIS)

    Papers presented at the UKAEA Conference on Materials Analysis by Physical Techniques (1987) covered a wide range of techniques as applied to the analysis of irradiated materials. These varied from reactor component materials, materials associated with the Authority's radwaste disposal programme, fission products and products associated with the decommissioning of nuclear reactors. An invited paper giving a very comprehensive review of Laser Ablation Microprobe Mass Spectroscopy (LAMMS) was included in the programme. (author)

  11. Advanced neutron absorber materials

    Science.gov (United States)

    Branagan, Daniel J. (Idaho Falls, ID); Smolik, Galen R. (Idaho Falls, ID)

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  12. Strength of Materials

    Science.gov (United States)

    Integrated Teaching and Leaning Program and Laboratory,

    Students learn about the variety of materials used by engineers in the design and construction of modern bridges. They also find out about the material properties important to bridge construction and consider the advantages and disadvantages of steel and concrete as common bridge-building materials to handle compressive and tensile forces.

  13. Fusion reactor materials

    International Nuclear Information System (INIS)

    This paper discuses the following topics on fusion reactor materials: irradiation, facilities, test matrices, and experimental methods; dosimetry, damage parameters, and activation calculations; materials engineering and design requirements; fundamental mechanical behavior; radiation effects; development of structural alloys; solid breeding materials; and ceramics

  14. Paramagnetic and Diamagnetic Materials

    Science.gov (United States)

    Thompson, Frank

    2011-01-01

    Paramagnetic and diamagnetic materials are now generally known as the "Cinderella" materials of the magnetic world. However, susceptibility measurements made on these materials in the past have revealed many details about the molecular bonding and the atomic structure of the so-called "transition" elements. Indeed, the magnetic moment of neodymium…

  15. Fissionable nuclear materials

    International Nuclear Information System (INIS)

    Physical, mechanical, and chemical properties of materials used as nuclear fuel in dispersion fuel elements (uranium dioxide, uranium carbide, uranium sulfides, plutonium dioxide) are under consideration. Particular emphasis is placed upon compatibility of these materials with a matrix, structural materials and coolants

  16. Materials for Space Exploration

    Science.gov (United States)

    Robertson, Luke B.; Williams, Martha

    2010-01-01

    Topics include a lab overview, testing and processing equipment, hemochromic hydrogen sensors, antimicrobial materials, wire system materials, CNT ink formulations, CNT ink dust screens, CNT ink printed circuitry, cryogenic materials development, fire and polymers, the importance of lighting, electric lighting systems, LED for plant growth, and carbon nanotube fiber filaments.

  17. Magnetism Materials and Applications

    CERN Document Server

    Trémolet de Lacheisserie, Étienne; Schlenker, Michel

    2005-01-01

    This book treats permanent magnet (hard) materials, magnetically soft materials for low-frequency applications and for high-frequency electronics, magnetostrictive materials, superconductors, magnetic-thin films and multilayers, and ferrofluids. Chapters are dedicated to magnetic recording, the role of magnetism in magnetic resonance imaging (MRI), and instrumentation for magnetic measurements.   

  18. Algoritma Pengujian Komposisi Material

    Directory of Open Access Journals (Sweden)

    Hendri Budiman

    2003-01-01

    Full Text Available The dynamic change of environment has made the factory must more competitive if they don't want to lose their market. To anticipate it can be by loosing un normal condition in production process. Material composition un appropriate by standard is un normal condition in foundry industry. To reach standard material composition is not simple because needed testing instrument and adjustment process. In software design needed a artificial intelligent can be adjust material composition. In the paper will be covered material composition testing algorithm for adjust material composition than material standard. Abstract in Bahasa Indonesia : Kondisi lingkungan yang dinamis membuat perusahaan harus lebih kompetitif dan meningkatkan fleksibilitas sistem manufakturnya agar tidak kehilangan pangsa pasarnya. Hal tersebut dicapai dengan menghilangkan kondisi tidak normal dalam proses produksinya. Komposisi material yang yang tidak sesuai dengan standar adalah suatu kondisi tidak normal dalam suatu pabrik pengecoran. Untuk mencapai komposisi yang sesuai dengan standar tidaklah mudah karena memerlukan alat uji dan proses penyesuaian (adjustment. Dalam perencanaan piranti lunak diperlukan suatu kecerdasaan buatan yang dapat menyesuaikan komposisi material . Dalam tulisan ini akan diulas algoritma pengujian komposisi material untuk menyesuaikan komposisi material yang dilebur dengan standar material. Kata kunci: Komposisi Material, Penyesuaian, Piranti lunak, kecerdasan buatan.

  19. Computing and Material

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Tamke, Martin

    2013-01-01

    The digital is often said to bring us away from material. The adverse is true: digital design and fabrication grants new interfaces towards material and allows architectural design to engage with material on architectural scale in a way that is further reaching than ever before.

  20. Transport of radioactive materials

    International Nuclear Information System (INIS)

    This ninth chapter presents de CNEN-NE--5.01 norm 'Transport of radioactive material'; the specifications of the radioactive materials for transport; the tests of the packages; the requests for controlling the transport and the responsibilities during the transport of radioactive material

  1. Tailored Porous Materials

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,THOMAS J.; BULL,LUCY M.; KLEMPERER,WALTER G.; LOY,DOUGLAS A.; MCENANEY,BRIAN; MISONO,MAKOTO; MONSON,PETER A.; PEZ,GUIDO; SCHERER,GEORGE W.; VARTULI,JAMES C.; YAGHI,OMAR M.

    1999-11-09

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities.

  2. Advances in electronic materials

    CERN Document Server

    Kasper, Erich; Grimmeiss, Hermann G

    2008-01-01

    This special-topic volume, Advances in Electronic Materials, covers various fields of materials research such as silicon, silicon-germanium hetero-structures, high-k materials, III-V semiconductor alloys and organic materials, as well as nano-structures for spintronics and photovoltaics. It begins with a brief summary of the formative years of microelectronics; now the keystone of information technology. The latter remains one of the most important global technologies, and is an extremely complex subject-area. Although electronic materials are primarily associated with computers, the internet

  3. Fusion Reactor Materials

    International Nuclear Information System (INIS)

    The objective of SCK-CEN's programme on fusion reactor materials is to contribute to the knowledge on the radiation-induced behaviour of fusion reactor materials and components as well as to help the international community in building the scientific and technical basis needed for the construction of the future reactor. Ongoing projects include: the study of the mechanical and chemical (corrosion) behaviour of structural materials under neutron irradiation and water coolant environment; the investigation of the characteristics of irradiated first wall material such as beryllium; investigations on the management of materials resulting from the dismantling of fusion reactors including waste disposal. Progress and achievements in these areas in 2001 are discussed

  4. Microporous polymeric materials

    Directory of Open Access Journals (Sweden)

    Peter M Budd

    2004-04-01

    Full Text Available Microporous materials are solids that contain interconnected pores of molecular dimensions (i.e. <2 nm. Such materials possess large surface areas, typically 300-1500 m2 g?1, and are of great technological importance for adsorption and heterogeneous catalysis1. There are two main classes of microporous materials widely used in industry: crystalline zeolites (aluminosilicates and activated carbons. In the past decade, there has been an intense effort to optimize the porosity of these materials for various applications2,3. However, it is recognized that the design of entirely new microporous materials would open up exciting opportunities for fundamental research and industrial applications3.

  5. New materials in defence

    International Nuclear Information System (INIS)

    National defence is very important and always needs new such materials which have technological and socio-economic development of human society. The types of materials used by a society reflect its level of sophistication. These modern materials are basically the same conventional materials but with a greater knowledge content which include superalloys, modern polymers, engineering ceramics and the advanced composite. The production and use of new materials is playing and important role in the recent development in the defence industry. (A.B.)

  6. Tailored porous materials

    International Nuclear Information System (INIS)

    Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form of fibers, thin films and monoliths. These issues are addressed in the context of five specific classes of porous materials: oxide molecular sieves, porous coordination solids, porous carbons, sol-gel derived oxides, and porous heteropolyanion salts. Reviews of these specific areas are preceded by a presentation of background material and review of current theoretical approaches to adsorption phenomena. A concluding section outlines current research needs and opportunities

  7. Applied Electromagnetism and Materials

    CERN Document Server

    Moliton, André

    2007-01-01

    Applied Electromagnetism and Materials picks up where the author's Basic Electromagnetism and Materials left off by presenting practical and relevant technological information about electromagnetic material properties and their applications. This book is aimed at senior undergraduate and graduate students as well as researchers in materials science and is the product of many years of teaching basic and applied electromagnetism. Topics range from the spectroscopy and characterization of dielectrics and semiconductors, to non-linear effects and electromagnetic cavities, to ion-beam applications in materials science.

  8. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  9. Amelioration de la procedure d'essai d'eclatement de joints d'etancheite a base de teflon

    Science.gov (United States)

    Benabdallah, Samir

    The objective of this work is to improve a HOt Blow-out Test procedure to determine the maximum operating temperature of Teflon-based gaskets. In parallel, an experimental fixture is developed to measure the thermal expansion coefficient of such material. This study aims to analyze the relaxation of PTFE gasketed joints due to creep at high temperature. The determination of the safe operating temperature limit of PTFE-based gaskets requires a good knowledge of its capacity to resist creep-relaxation due to temperature exposure in the short and long term. The aim of this work is to improve the HOBT standard procedure « Standard Test Method for Hot Blowout and Thermal Cycling Performance for Polytetrafluoroethylene (PTFE) Sheet or Sheet-Like Gaskets» which is under adoption by the ASTM F03 gasket committee. Based on a previous work, the introduction of a fixed number of cycles of heating and cooling in the HOBT test procedure has shown that the cumulative permanent deformation (ratcheting damage) which has impact on reduction of the gasket stress can be taken into account. The effect of holding temperature for a short period of time will be investigated. The modified HOBT rig allows measurement of the gasket compression during the test in order to accurately quantify the cumulative permanent deformation. Several types of PTFE-based gaskets will be tested in order to cover a wide range of gaskets to justify the generalization of the modified procedure. The different steps to achieve this project are listed below: 1. Improve the HOBT test rig by implementing a device to measure gasket compression and it variation with the thermal cycles. 2. Study the effects of the number of thermal cycling and the holding temperature on the gasket stress and the cumulative permanent deformation and the short term creep on the hot blowout characteristics of PTFE-based gaskets. 3. Development of a small fixture to measure the coefficient of thermal expansion of gasketing materials under high loads. This fixture can also measure other mechanical properties such as load compression and short term creep at high temperature. 4. Tests of hot blowout, load compression, creep and measurement of the coefficient of thermal expansion will be conducted on several PTFE-based gaskets.

  10. Prime materials industries: Materials substitution and relocation

    International Nuclear Information System (INIS)

    The years spanning 1960-1990 witnessed a marked reduction of industrial sector impact on the gross national products of the OECD nations and a contemporaneous relocation of high energy intensity industries towards developing countries. The correlation between prime materials demand and industrial production is becoming less significant as advanced industrial systems orient themselves towards the use of fifth generation materials. Energy conservation policies have led to notable reductions in the use of metals. This evolution of OECD economies towards post-industrial societies with very low consumption of prime materials has contributed to a substantial reduction in energy demand in industry. However, this paper shows that there are counterbalancing factors at work which are not drastically reducing the energy demand in the industrial sector at the world level

  11. Materials and design interface

    International Nuclear Information System (INIS)

    The unprecedented demands faced by fusion structures primarily derive from severe time varying thermal-mechanical loading of complex, large scale, and highly interconnected heat transfer-energy conversion structures. This grand challenge is often much too narrowly couched in terms of the development of radiation damage resistant materials, while the enormously larger challenge is the creation of material systems and multifunctional structures. In addition, the fusion system designer is faced with the untenable situation that neither the fully functional materials, nor the requisite computational tools, nor experimental simulation facilities currently exist for reliable integrity and lifetime assessments of fusion reactor structures. Considering the absence of material information and design tools, neither the materials nor the fusion designer can follow standard design processes. The design process has to become actively materials-related while materials development must closely follow design process needs. This indispensible interaction between materials and design processes leads to a 'concurrent materials-structure design' path, which is necessary to meet the enormous materials-structural engineering challenges of fusion.

  12. Ceramic piezoelectric materials

    International Nuclear Information System (INIS)

    Ceramic piezoelectric materials conert reversibility electric energy into mechanical energy. In the presence of electric field piezoelectric materials exhibit deformations up to 0.15% (for single crystals up to 1.7%). The deformation energy is in the range of 102 - 103 J/m3 and working frequency can reach 105 Hz. Ceramic piezoelectric materials find applications in many modern disciplines such as: automatics, micromanipulation, measuring techniques, medical diagnostics and many others. Among the variety of ceramic piezoelectric materials the most important appear to be ferroelectric materials such as lead zirconate titanate so called PZT ceramics. Ceramic piezoelectric materials can be processed by methods widely applied for standard ceramics, i.e. starting from simple precursors e.g. oxides. Application of sol-gel method has also been reported. Substantial drawback for many applications of piezoelectric ceramics is their brittleness, thus much effort is currently being put in the development of piezoelectric composite materials. Other important research directions in the field of ceramic piezoelectric materials composite development of lead free materials, which can exhibit properties similar to the PZT ceramics. Among other directions one has to state processing of single crystals and materials having texture or gradient structure. (author)

  13. Uranium reference materials

    International Nuclear Information System (INIS)

    The Technical Measurements Center has prepared uranium mill tailings reference materials for use by remedial action contractors and cognizant federal and state agencies. Four materials were prepared with varying concentrations of radionuclides, using three tailings materials and a river-bottom soil diluent. All materials were ground, dried, and blended thoroughly to ensure homogeneity. The analyses on which the recommended values for nuclides in the reference materials are based were performed, using independent methods, by the UNC Geotech (UNC) Chemistry Laboratory, Grand Junction, Colorado, and by C.W. Sill (Sill), Idaho National Engineering Laboratory, Idaho Falls, Idaho. Several statistical tests were performed on the analytical data to characterize the reference materials. Results of these tests reveal that the four reference materials are homogeneous and that no large systematic bias exists between the analytical methods used by Sill and those used by TMC. The average values for radionuclides of the two data sets, representing an unbiased estimate, were used as the recommended values for concentrations of nuclides in the reference materials. The recommended concentrations of radionuclides in the four reference materials are provided. Use of these reference materials will aid in providing uniform standardization among measurements made by remedial action contractors. 11 refs., 9 tabs

  14. Articulating Material Criteria

    DEFF Research Database (Denmark)

    Hasling, Karen Marie

    This paper discusses the experiences and potentials with materials teaching at the Institute for Product Design at Kolding School of Design, using materials teaching as experiments in my PhD project. The project intents to create a stronger material awareness among product design students with emphasis on sustainability. The experiments aim to develop an understanding of, how product design students include materials in their design practice and how tools can be developed that further enhance this. Hence experiments are essential for the progress of the PhD project as they help to observe, imitate and articulate the students’ inclusion of materials. This paper particularly discusses the experiences made and ideas generated after the execution of a material science course for second year students, with emphasis on the concept of the material selection matrix as an educational tool for material exploration. The course was the first course I was involved in as a PhD student and has served as the first observation case in my project. The purpose of this analysis has been to explore and demonstrate that data from material selection matrices generated during the course, help mature the tool. Furthermore the purpose is to initiate a discussion on, how to create educational tools for material awareness creation in the design education e.g. by applying objective and quantitative methods in an otherwise often subjective design process.

  15. Preliminary studies of radioactive wastes immobilization, using microwaves, in asphaltic matrices and elastomeric residues; Estudos preliminares da imobilizacao de rejeitos radioativos, com microondas, em matrizes asfalticas e residuos elastomericos

    Energy Technology Data Exchange (ETDEWEB)

    Caratin, Reinaldo Leonel; Araujo, Sumair Gouveia de; Landini, Liliane; Jaquier, Gilberto da Silva; Lugao, Ademar Benevolo [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rcaratin@ipen.br; sgaraujo@ipen.br; landini@usp.br; gilbertojaquier@ibest.com.br; ablugao@ipen.br

    2005-07-01

    The present work consists of preliminary studies for immobilization of radioactive waste by using monolithic solid matrices compounded by bitumen (asphalt) and production leftovers of EVA shoe soles (polymeric residues). Those matrices were obtained through high microwave energy heating aiming to reduce possible dispersion of radioactive material in the environment during the stages of intermediate storage, transportation and final disposal. The radioactive waste that was used results from the purification of thorium long made at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). The obtained precipitate is named Retoter (thorium residue and rare earth elements). The compounded samples of bitumen and rubber were heated by electromagnetic radiation (high microwave energy); the time was varied and the temperature was controlled. Variables such as mass percent of bitumen/rubber, dosage, microwave power, heating period and temperature were analyzed in order to get the most homogeneous formulations that might be most resistant to environmental agents. The geometry of samples is still being studied to obtain the best distribution of radioactive waste on the polymeric compound (bitumen/rubber). To prove the efficiency of the method, physics and chemistry characterizations have been initially made through assays in order to evidence properties like: porosity, density, leaching rate, resistance to radiation, resistance to aging, thermal, mechanical and structural properties. (author)

  16. Fusion reactor materials

    International Nuclear Information System (INIS)

    This is the fifteenth in a series of semiannual technical progress reports on fusion reactor materials. This report combines research and development activities which were previously reported separately in the following progress reports: Alloy Development for Irradiation Performance; Damage Analysis and Fundamental Studies; Special purpose Materials. These activities are concerned principally with the effects of the neutronic and chemical environment on the properties and performance of reactor materials; together they form one element of the overall materials programs being conducted in support of the Magnetic Fusion Energy Program of the U.S. Department of Energy. The Fusion Reactor Materials Program is a national effort involving several national laboratories, universities, and industries. The purpose of this series of reports is to provide a working technical record for the use of the program participants, and to provide a means of communicating the efforts of materials scientists to the rest of the fusion community, both nationally and worldwide

  17. Designing Material Materialising Design

    DEFF Research Database (Denmark)

    Nicholas, Paul

    2013-01-01

    Designing Material Materialising Design focuses on the design of elastically tailored composite architectural structures. Emerging technologies around synthetic materials can now support the precise specification of materials and their properties. This book moves away the conception of material as an unresisting receptacle for forms determined in advance to explore the architectural implications of synthetic materials and design methods for calibrated material behaviour. It includes case studies developed at the Center for Information Technology and Architecture (CITA) at the Royal Danish Academy of Fine Arts, School of Architecture in Copenhagen. Novel concepts and operational models are illustrated that specify and materialise causal relationships between configuration and transformation. These projects reveal a new locus of architectural instruction that require new kinds of design information, new representational models, and different modes of design control.

  18. Automatic material identifier

    International Nuclear Information System (INIS)

    Radiation survey instruments could be used to verify the presence of radioactive material inside a container, but identification of the material would not be possible. One could imagine a very complex detector-analyzer system to analyze the radiation being emitted from a container, but it would be very large and difficult to use. At Los Alamos, a portable instrument with some limitations has been developed to identify plutonium and uranium inside a container. The instrument consists of a thin NaI crystal and an electronics package which is based on a microcomputer. The instrument uses the energy spectrum of the emitted radiation to identify the nuclear material present. The function of this instrument is to provide the user a tool for qualitative verification of nuclear materials in a container. The instrument can distinguish plutonium-239 and uranium-235 from other radioactive materials. A count rate indicator provides some measure of the quantity of material. 1 reference, 2 figures

  19. Hydrophilic nanoporous materials

    DEFF Research Database (Denmark)

    Berg, Rolf Henrik Technical University of Denmark,

    The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.05, the method comprising the steps of: (a) preparing a precursor material comprising at least one polymeric component and having a first phase and a second phase; (b) removal of at least a part of the first phase of the precursor material prepared in step (a) so as to leave behind a nanoporous material of the polymer matrix; (c) irradiating at least a part of said nanoporous material with light of a wave length of in the range of 250-400 nm (or 200-700 nm) in the presence of oxygen and/or ozone. Corresponding hydrophilic nanoporous materials are also disclosed. L

  20. Material behavior and materials problems in TFTR

    Science.gov (United States)

    Dylla, H. F.; Ulrickson, M. A.; Owens, D. K.; Heifetz, D. B.; Mills, B. E.; Pontau, A. E.; Wampler, W. R.; Doyle, B. L.; Lee, S. R.; Watson, R. D.; Croessmann, C. D.

    1988-07-01

    This paper reviews the experience with first-wall materials in TFTR over a 20 month period of operatiori during 1985-1987. Experience with the axisymmetric inner wall limiter, constructed of graphite tiles, is described, including the necessary conditioning procedures needed for impurity and particle control of high power (? 20 MW) neutral injection experiments. The thermal effects in disruptions have been quantified and no significant damage to the bumper limiter has occurred as a result of disruptions. Carbon and metal impurity redeposition effects have been quantified through surface analysis of wall samples. Estimates of the tritium retention in the graphite limiter tiles and redeposited carbon films have been made, based on analysis of deuterium retention in removed graphite tiles and wall samples. New limiter structures have been designed using a 2D carbon/carbon ( {C}/{C}) composite material for RF antenna protection. Laboratory tests of the important thermal, mechanical, and vacuum properties of {C}/{C} materials are described. Finally, the last series of experiments in TFTR with in-situ {Zr}/{Al} surface pumps are discussed. Problems with {Zr}/{Al} embrittlement have led to the removal of the getter material from the in-torus environment.

  1. Material behavior and materials problems in TFTR

    International Nuclear Information System (INIS)

    This paper reviews the experience with first-wall materials in TFTR over a 20 month period of operation during 1985-1987. Experience with the axisymmetric inner wall limiter, constructed of graphite tiles, is described, including the necessary conditioning procedures needed for impurity and particle control of high power (? 20 MW) neutral injection experiments. The thermal effects in disruptions have been quantified and no significant damage to the bumper limiter has occurred as a result of disruptions. Carbon and metal impurity redeposition effects have been quantified through surface analysis of wall samples. Estimates of the tritium retention in the graphite limiter tiles and redeposited carbon films have been made, based on analysis of deuterium retention in removed graphite tiles and wall samples. New limiter structures have been designed using a 2D carbon/carbon (C/C) composite material for RF antenna protection. Laboratory tests of the important thermal, mechanical, and vacuum properties of C/C materials are described. Finally, the last series of experiments in TFTR with in-situ Zr/Al surface pumps are discussed. Problems with Zr/Al embrittlement have led to the removal of the getter material from the in-torus environment. (orig.)

  2. Heterogeneous Materials I and Heterogeneous Materials II

    International Nuclear Information System (INIS)

    In these two volumes the author provides a comprehensive survey of the various mathematically-based models used in the research literature to predict the mechanical, thermal and electrical properties of hetereogeneous materials, i.e., materials containing two or more phases such as fibre-reinforced polymers, cast iron and porous ceramic kiln furniture. Volume I covers linear properties such as linear dielectric constant, effective electrical conductivity and elastic moduli, while Volume II covers nonlinear properties, fracture and atomistic and multiscale modelling. Where appropriate, particular attention is paid to the use of fractal geometry and percolation theory in describing the structure and properties of these materials. The books are advanced level texts reflecting the research interests of the author which will be of significant interest to research scientists working at the forefront of the areas covered by the books. Others working more generally in the field of materials science interested in comparing predictions of properties with experimental results may well find the mathematical level quite daunting initially, as it is apparent that the author assumes a level of mathematics consistent with that taught in final year undergraduate and graduate theoretical physics courses. However, for such readers it is well worth persevering because of the in-depth coverage to which the various models are subjected, and also because of the extensive reference lists at cause of the extensive reference lists at the back of both volumes which direct readers to the various source references in the scientific literature. Thus, for the wider materials science scientific community the two volumes will be a valuable library resource. While I would have liked to see more comparison with experimental data on both ideal and 'real' heterogeneous materials than is provided by the author and a discussion of how to model strong nonlinear current--voltage behaviour in systems such as zinc oxide varistors, my overall impression of the books is that together they are an impressive tour de force and provide a valuable summary of the state of knowledge of the mathematical modelling of heterogeneous materials as we begin the 21st century. (book review)

  3. DEVELOPMENT OF LEARNING MATERIAL

    OpenAIRE

    Salminen, Tomi

    2011-01-01

    The purpose of this thesis was to develop learning material to support the Quality tools lectures. The topic of this thesis was generated by Pasi-Waltteri Valtanen, out of need for learning material that supports the Quality tools lectures. Topics which the learning material was creates were Quality Function Deployment (QFD), Design of Experiments (DOE), Failure Mode and Effect Analysis (FMEA), Statistical Process Control (SPC) and the Taguchi method These topics were chosen beca...

  4. Broken Bones & Biomedical Materials

    Science.gov (United States)

    2014-09-18

    Students are introduced to the concept and steps of the engineering design process and taught how to apply it. Students first receive some background information about biomedical engineering (aka bioengineering). Then they learn about material selection and material properties by using a provided guide. In small groups, students learn of their design challenge (improve a cast for a broken arm), brainstorm solutions, are given materials and create prototypes. To finish, teams communicate their design solutions through class poster presentations.

  5. Refractory materials and plasma

    International Nuclear Information System (INIS)

    This note is an overview of current developments in the field of refractory materials using plasma processes. In this sector, which often necessitates high temperatures, it is surprising to note that few plasma processes have been developed for industrial production purposes. Three aspects or three types of application are discussed: -melting or remelting of oxidized refractory materials (electromelted materials) -synthesis of refractory powders, notably oxides, carbides or nitrides -spheroidizing of refractory oxide powders. (author). 43 refs., 13 figs

  6. Alloy catalyst material

    DEFF Research Database (Denmark)

    Stephens, Ifan Technical University of Denmark,

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water.

  7. ANS materials databook

    Energy Technology Data Exchange (ETDEWEB)

    Marchbanks, M.F.

    1995-08-01

    Technical development in the Advanced Neutron Source (ANS) project is dynamic, and a continuously updated information source is necessary to provide readily usable materials data to the designer, analyst, and materials engineer. The Advanced Neutron Source Materials Databook (AMBK) is being developed as a part of the Advanced Neutron Source Materials Information System (AMIS). Its purpose is to provide urgently needed data on a quick-turnaround support basis for those design applications whose schedules demand immediate estimates of material properties. In addition to the need for quick materials information, there is a need for consistent application of data throughout the ANS Program, especially where only limited data exist. The AMBK is being developed to fill this need as well. It is the forerunner to the Advanced Neutron Source Materials Handbook (AMHB). The AMHB, as reviewed and approved by the ANS review process, will serve as a common authoritative source of materials data in support of the ANS Project. It will furnish documented evidence of the materials data used in the design and construction of the ANS system and will serve as a quality record during any review process whose objective is to establish the safety level of the ANS complex. The information in the AMBK and AMHB is also provided in electronic form in a dial-up computer database known as the ANS Materials Database (AMDB). A single consensus source of materials information prepared and used by all national program participants has several advantages. Overlapping requirements and data needs of various sub-projects and subcontractors can be met by a single document which is continuously revised. Preliminary and final safety analysis reports, stress analysis reports, equipment specifications, materials service reports, and many other project-related documents can be substantially reduced in size and scope by appropriate reference to a single data source.

  8. Fretynhostiykist composite materials

    Directory of Open Access Journals (Sweden)

    ?.?. ?????

    2009-01-01

    Full Text Available  Tests of composite materials were made for wearability in fretting condition. Different binding materials, different quantity of reinforcement layer were used for testing whith steel of 30???? and alloy of ?16. It was set that combination of ?-10-14 (four layers of glass fabric and binders ???-69? and 5-211-?? has better characteristics of wearability. Recommendations for reducing of composite material's fretting were designed.

  9. Micromechanics of heterogeneous materials

    CERN Document Server

    Buryachenko, Valeriy

    2007-01-01

    The book features unified rigorous theoretical methods of applied mathematics and statistical physics in material science of microheterogeneous media. The prediction of the behavior of heterogeneous materials by the use of properties of constituents and their microstructure is a central issue of micromechanics. This book is the first in micromechanics with a useful and effective demonstration of the systematic and fundamental research of the microstructure of the wide class of heterogeneous materials of natural and synthetic nature.

  10. Building Materials and Finishes

    OpenAIRE

    Yiagouli, Yiangos G.

    1993-01-01

    Building materials, is a huge subject. It covers almost all materials that are used in building industry even finishes, but in this project are separated. This project deals mainly with Concrete, bricks, Aggregates and mortar as building materials. Insulation (thermal and moisture), and comemment and outline. Finishes are separated as wall finishes and floor finishes, and the way that they must be used. Therefore, the project is divided into seven chapter: Chapter 1: Deals about t...

  11. Multilayer Insulation Material Guidelines

    Science.gov (United States)

    Finckenor, M. M.; Dooling, D.

    1999-01-01

    Multilayer Insulation Material Guidelines provides data on multilayer insulation materials used by previous spacecraft such as Spacelab and the Long-Duration Exposure Facility and outlines other concerns. The data presented in the document are presented for information only. They can be used as guidelines for multilayer insulation design for future spacecraft provided the thermal requirements of each new design and the environmental effects on these materials are taken into account.

  12. Materials Made to Last

    International Nuclear Information System (INIS)

    High temperatures, irradiation, mechanical stresses, corrosive environments, etc. The materials used in nuclear power plants are subjected to extreme conditions. Guaranteeing the safety, lifespan and performance levels of current reactors, while designing and qualifying new materials capable of resisting the specific constraints of future nuclear systems, are the main issues investigated at the CEA-DEN in the field of nuclear materials. To meet these requirements, researchers at the CEA have access to a wealth of feedback, skills and unparalleled experimental facilities. (authors)

  13. Frontiers in Superconducting Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Superconducting Materials gives a state-of-the-art report of the most important topics of the current research in superconductive materials and related phenomena. It comprises 30 chapters written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students. It also addresses electronic and electrical engineers. Even non-specialists interested in superconductivity might find some useful answers.

  14. ANS materials databook

    International Nuclear Information System (INIS)

    Technical development in the Advanced Neutron Source (ANS) project is dynamic, and a continuously updated information source is necessary to provide readily usable materials data to the designer, analyst, and materials engineer. The Advanced Neutron Source Materials Databook (AMBK) is being developed as a part of the Advanced Neutron Source Materials Information System (AMIS). Its purpose is to provide urgently needed data on a quick-turnaround support basis for those design applications whose schedules demand immediate estimates of material properties. In addition to the need for quick materials information, there is a need for consistent application of data throughout the ANS Program, especially where only limited data exist. The AMBK is being developed to fill this need as well. It is the forerunner to the Advanced Neutron Source Materials Handbook (AMHB). The AMHB, as reviewed and approved by the ANS review process, will serve as a common authoritative source of materials data in support of the ANS Project. It will furnish documented evidence of the materials data used in the design and construction of the ANS system and will serve as a quality record during any review process whose objective is to establish the safety level of the ANS complex. The information in the AMBK and AMHB is also provided in electronic form in a dial-up computer database known as the ANS Materials Database (AMDB). A single consensus source of materials information prepared and used by all national program participants has several advantages. Overlapping requirements and data needs of various sub-projects and subcontractors can be met by a single document which is continuously revised. Preliminary and final safety analysis reports, stress analysis reports, equipment specifications, materials service reports, and many other project-related documents can be substantially reduced in size and scope by appropriate reference to a single data source

  15. Absolute nuclear material assay

    Science.gov (United States)

    Prasad, Manoj K. (Pleasanton, CA); Snyderman, Neal J. (Berkeley, CA); Rowland, Mark S. (Alamo, CA)

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  16. Materials engineering for immunomodulation

    OpenAIRE

    Jeffrey A. Hubbell; Thomas, Susan N.; Swartz, M. A.

    2009-01-01

    The engineering of materials that can modulate the immune system is an emerging field that is developing alongside immunology. For therapeutic ends such as vaccine development, materials are now being engineered to deliver antigens through specific intracellular pathways, allowing better control of the way in which antigens are presented to one of the key types of immune cell, T cells. Materials are also being designed as adjuvants, to mimic specific 'danger' signals in order to manipulate th...

  17. Radiation Modification of Materials

    International Science & Technology Center (ISTC)

    Development of Physical and Chemical Principles for Radiation Techniques of Material Modification by Electrons, Polyenergetic Ions and High Temperature Plasma Fluxes (Phase of Feasibility and Market Study)

  18. H2FC: Materials

    Science.gov (United States)

    The Hydrogen and Fuel Cell Investor, an online resource covering fuel cell technologies and companies, hosts these pages on technology and materials of hydrogen fuel cells. The Materials page is a metapage with links to information about Hydrogen, H2 Storage Materials, Hydrogen Rich Fuels, Fuel Cell Components, and Metals. Examples of links found at the Materials page include Handling Hydrogen Safely (from the National Hydrogen Association), Hydride Information Center (Sandia National Laboratories), "Synthesis, Properties and Applications of Graphite Nanofibers" (research paper from Northeastern University), The American Methanol Institute, and a solubility graph for selected metals (from REB Research Services).

  19. Frontiers in Magnetic Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Magnetic Materials focuses on the current achievements and state-of-the-art advancements in magnetic materials. Several lines of development- High-Tc Superconductivity, Nanotechnology and refined experimental techniques among them – raised knowledge and interest in magnetic materials remarkably. The book comprises 24 chapters on the most relevant topics written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students.

  20. Multifunctional Composite Materials Project

    National Aeronautics and Space Administration — Polymeric composite materials that are currently utilized in aircraft structures are susceptible to significant damage from lightning strikes. Enhanced electrical...

  1. Advanced Aircraft Material

    Directory of Open Access Journals (Sweden)

    Vivek Kumar Prince

    2013-06-01

    Full Text Available There has been long debate on “advanced aircraft material” from past decades & researchers too came out with lots of new advanced material like composites and different aluminum alloys. Now days a new advancement that is in great talk is third generation Aluminum-lithium alloy. Newest Aluminum-lithium alloys are found out to have low density, higher elastic modulus, greater stiffness, greater cryogenic toughness, high resistance to fatigue cracking and improved corrosion resistance properties over the earlier used aircraft material as mentioned in Table 3 [1-5]. Comparison had been made with nowadays used composite material and is found out to be more superior then that

  2. Phase change materials

    CERN Document Server

    Raoux, Simone

    2010-01-01

    ""Phase Change Materials: Science and Applications"" provides a unique introduction of this rapidly developing field. Clearly written and well-structured, this volume describes the material science of these fascinating materials from a theoretical and experimental perspective. Readers will find an in-depth description of their existing and potential applications in optical and solid state storage devices as well as reconfigurable logic applications. Researchers, graduate students and scientists with an interest in this field will find ""Phase Change Materials"" to be a valuable reference.

  3. Reactor Materials Research

    International Nuclear Information System (INIS)

    The activities of SCK-CEN's Reactor Materials Research Department for 2001 are summarised. The objectives of the department are: (1) to evaluate the integrity and behaviour of structural materials used in nuclear power industry; (2) to conduct research to unravel and understand the parameters that determine the material behaviour under or after irradiation; (3) to contribute to the interpretation, the modelling of the material behaviour and to develop and assess strategies for optimum life management of nuclear power plant components. The programmes within the department are focussed on studies concerning (1) Irradiation Assisted Stress Corrosion Cracking (IASCC); (2) nuclear fuel; and (3) Reactor Pressure Vessel Steel

  4. Thermoelectric materials having porosity

    Science.gov (United States)

    Heremans, Joseph P.; Jaworski, Christopher M.; Jovovic, Vladimir; Harris, Fred

    2014-08-05

    A thermoelectric material and a method of making a thermoelectric material are provided. In certain embodiments, the thermoelectric material comprises at least 10 volume percent porosity. In some embodiments, the thermoelectric material has a zT greater than about 1.2 at a temperature of about 375 K. In some embodiments, the thermoelectric material comprises a topological thermoelectric material. In some embodiments, the thermoelectric material comprises a general composition of (Bi.sub.1-xSb.sub.x).sub.u(Te.sub.1-ySe.sub.y).sub.w, wherein 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 1.8.ltoreq.u.ltoreq.2.2, 2.8.ltoreq.w.ltoreq.3.2. In further embodiments, the thermoelectric material includes a compound having at least one group IV element and at least one group VI element. In certain embodiments, the method includes providing a powder comprising a thermoelectric composition, pressing the powder, and sintering the powder to form the thermoelectric material.

  5. Reactor Materials Research

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E

    2002-04-01

    The activities of SCK-CEN's Reactor Materials Research Department for 2001 are summarised. The objectives of the department are: (1) to evaluate the integrity and behaviour of structural materials used in nuclear power industry; (2) to conduct research to unravel and understand the parameters that determine the material behaviour under or after irradiation; (3) to contribute to the interpretation, the modelling of the material behaviour and to develop and assess strategies for optimum life management of nuclear power plant components. The programmes within the department are focussed on studies concerning (1) Irradiation Assisted Stress Corrosion Cracking (IASCC); (2) nuclear fuel; and (3) Reactor Pressure Vessel Steel.

  6. Materials information data bank

    International Nuclear Information System (INIS)

    A major concern in the design of weapons systems is compatibility of materials with each other and with the enclosed environment. Usually these systems require long-term storage and must have high reliability at the end of this storage period. Materials selection is thus based on past experience and on laboratory-accelerated testing to assure this long-term reliability. To assist in materials selection, a computerized materials data bank has been established. In addition to references on personnel and documents, this data bank provides annotated information on materials so that the designer and materials engineer can draw on it for guidance in selecting materials. The primary purpose of the data bank is to provide materials compatibility data. However, the structure of the system permits the data bank to be used for storage and retrieval of general materials information. The data bank storage and information retrieval philosophy is discussed and procedures for information gathering are outlined. Examples of data entries and a list of search routines are presented to demonstrate the usefulness and versatility of the system

  7. Materials Science Laboratory

    Science.gov (United States)

    Jackson, Dionne

    2005-01-01

    The NASA Materials Science Laboratory (MSL) provides science and engineering services to NASA and Contractor customers at KSC, including those working for the Space Shuttle. International Space Station. and Launch Services Programs. These services include: (1) Independent/unbiased failure analysis (2) Support to Accident/Mishap Investigation Boards (3) Materials testing and evaluation (4) Materials and Processes (M&P) engineering consultation (5) Metrology (6) Chemical analysis (including ID of unknown materials) (7) Mechanical design and fabrication We provide unique solutions to unusual and urgent problems associated with aerospace flight hardware, ground support equipment and related facilities.

  8. Materials Research at Studsvik

    International Nuclear Information System (INIS)

    The report gives an appraisement of the materials research at Studsvik during the period from 1972 to 1979. The study has been concentrated on metallic materials with glances at polymers, ceramics and composite materials. The research which has been financed by the National Swedish Board for Technical Development has a position between basic research and the applied research at industry. Its purpose has been to assist the Swedish projects for nuclear power and it is now expanding towards energy research in general. Another field of activity is testing of materials and standardization of testing methods. The report presents recommendations concerning future work at Studsvik. (G.B.)

  9. Spacecraft Material Outgassing Data

    National Aeronautics and Space Administration — This compilation of outgassing data of materials intended for spacecraft use were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed...

  10. Advanced thermal management materials

    CERN Document Server

    Jiang, Guosheng; Kuang, Ken

    2012-01-01

    ""Advanced Thermal Management Materials"" provides a comprehensive and hands-on treatise on the importance of thermal packaging in high performance systems. These systems, ranging from active electronically-scanned radar arrays to web servers, require components that can dissipate heat efficiently. This requires materials capable of dissipating heat and maintaining compatibility with the packaging and dye. Its coverage includes all aspects of thermal management materials, both traditional and non-traditional, with an emphasis on metal based materials. An in-depth discussion of properties and m

  11. The Materials Genome Project

    Science.gov (United States)

    Aourag, H.

    2008-09-01

    In the past, the search for new and improved materials was characterized mostly by the use of empirical, trial- and-error methods. This picture of materials science has been changing as the knowledge and understanding of fundamental processes governing a material's properties and performance (namely, composition, structure, history, and environment) have increased. In a number of cases, it is now possible to predict a material's properties before it has even been manufactured thus greatly reducing the time spent on testing and development. The objective of modern materials science is to tailor a material (starting with its chemical composition, constituent phases, and microstructure) in order to obtain a desired set of properties suitable for a given application. In the short term, the traditional "empirical" methods for developing new materials will be complemented to a greater degree by theoretical predictions. In some areas, computer simulation is already used by industry to weed out costly or improbable synthesis routes. Can novel materials with optimized properties be designed by computers? Advances in modelling methods at the atomic level coupled with rapid increases in computer capabilities over the last decade have led scientists to answer this question with a resounding "yes'. The ability to design new materials from quantum mechanical principles with computers is currently one of the fastest growing and most exciting areas of theoretical research in the world. The methods allow scientists to evaluate and prescreen new materials "in silico" (in vitro), rather than through time consuming experimentation. The Materials Genome Project is to pursue the theory of large scale modeling as well as powerful methods to construct new materials, with optimized properties. Indeed, it is the intimate synergy between our ability to predict accurately from quantum theory how atoms can be assembled to form new materials and our capacity to synthesize novel materials atom-by-atom that gives to the Materials Genome Project its extraordinary intellectual vitality. Consequently, in designing new materials through computer simulation, our primary objective is to rapidly screen possible designs to find those few that will enhance the competitiveness of industries or have positive benefits to society. Examples include screening of cancer drugs, advances in catalysis for energy production, design of new alloys and multilayers and processing of semiconductors.

  12. Fusion Reactor Materials

    International Nuclear Information System (INIS)

    The objective of SCK-CEN's programme on fusion reactor materials is to contribute to the knowledge on the behaviour of fusion reactor materials and components during and after irradiation. Ongoing projects include: the study of the mechanical behaviour of structural materials under neutron irradiation; the investigation of the characteristics of irradiated first wall material such as beryllium; the detection of abrupt electrical degradation of insulating ceramics under high temperature and neutron irradiation; and the study of dismantling and waste disposal strategy for fusion reactors. Progress and achievements in these areas in 2000 are discussed

  13. Ceramic breeder materials

    International Nuclear Information System (INIS)

    Ceramic materials are under investigation as potential breeder material in fusion reactors. This paper will review candidate materials with respect to fabrication routes and characterization, properties in as-fabricated and irradiated condition, and experimental results from laboratory and inpile investigations on tritium transport and release. Also discussed are the resources of beryllium, which is being considered as a neutron multiplier. The comparison of ceramic properties that is attempted here aims at the identification of the most-promising material for use in a tritium breeding blanket. 82 refs., 12 figs., 5 tabs

  14. Biogenic Impact on Materials

    Science.gov (United States)

    Stephan, Ina; Askew, Peter; Gorbushina, Anna; Grinda, Manfred; Hertel, Horst; Krumbein, Wolfgang; Müller, Rolf-Joachim; Pantke, Michael; Plarre, Rüdiger (Rudy); Schmitt, Guenter; Schwibbert, Karin

    Materials as constituents of products or components of technical systems rarely exist in isolation and many must cope with exposure in the natural world. This chapter describes methods that simulate how a material is influenced through contact with living systems such as microorganisms and arthropods. Both unwanted and desirable interactions are considered. This biogenic impact on materials is intimately associated with the environment to which the material is exposed (Materials-Environment Interaction, Chap. 15). Factors such as moisture, temperature and availability of food sources all have a significant influence on biological systems. Corrosion (Chap. 12) and wear (Chap. 13) can also be induced or enhanced in the presence of microorganisms. Section 14.1 introduces the categories between desired (biodegradation) and undesired (biodeterioration) biological effects on materials. It also introduces the role of biocides for the protection of materials. Section 14.2 describes the testing of wood as a building material especially against microorganisms and insects. Section 14.3 characterizes the test methodologies for two other groups of organic materials, namely polymers (Sect. 14.3.1) and paper and textiles (Sect. 14.3.2). Section 14.4 deals with the susceptibility of inorganic materials such as metals (Sect. 14.4.1), concrete (Sect. 14.4.2) and ceramics (Sect. 14.4.3) to biogenic impact. Section 14.5 treats the testing methodology concerned with the performance of coatings and coating materials. In many of these tests specific strains of organisms are employed. It is vital that these strains retain their ability to utilize/attack the substrate from which they were isolated, even when kept for many years in the laboratory. Section 14.6 therefore considers the importance of maintaining robust and representative test organisms that are as capable of utilizing a substrate as their counterparts in nature such that realistic predictions of performance can be made.

  15. Gravitation in Material Media

    Science.gov (United States)

    Ridgely, Charles T.

    2011-01-01

    When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium…

  16. Packaging Your Training Materials

    Science.gov (United States)

    Espeland, Pamela

    1977-01-01

    The types of packaging and packaging materials to use for training materials should be determined during the planning of the training programs, according to the packaging market. Five steps to follow in shopping for packaging are presented, along with a list of packaging manufacturers. (MF)

  17. Scintillator materials for calorimetry

    International Nuclear Information System (INIS)

    Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented

  18. Environmental materials and interfaces

    International Nuclear Information System (INIS)

    A workshop that explored materials and interfaces research needs relevant to national environmental concerns was conducted at Pacific Northwest Laboratory. The purposes of the workshop were to refine the scientific research directions being planned for the Materials and Interface Program in the Molecular Science Research Center (MSRC) and further define the research and user equipment to the included as part of the proposed Environmental and Molecular Science Laboratory (EMSL). Three plenary information sessions served to outline the background, objectives, and status of the MSRC and EMSL initiatives; selected specific areas with environmentally related materials; and the status of capabilities and facilities planned for the EMSL. Attention was directed to four areas where materials and interface science can have a significant impact on prevention and remediation of environmental problems: in situ detection and characterization of hazardous wastes (sensors), minimization of hazardous waste (separation membranes, ion exchange materials, catalysts), waste containment (encapsulation and barrier materials), and fundamental understanding of contaminant transport mechanisms. During all other sessions, the participants were divided into three working groups for detailed discussion and the preparation of a written report. The working groups focused on the areas of interface structure and chemistry, materials and interface stability, and materials synthesis. These recommendations and suggestions for needed research will be useful for other researchers in proposing projects and for suggesting collaborative work with MSRC researchers. 1 fig

  19. Materials modified by irradiation

    International Nuclear Information System (INIS)

    Application of radiation in pharmaceutical sciences and cosmetology, polymer materials, food industry, environment, health camre products and packing production is described. Nano-technology is described more detailed, because it is less known as irradiation using technology. Economic influence of the irradiation on the materials value addition is shown

  20. Super Soaking Materials

    Science.gov (United States)

    Twin Cities Public Television, Inc.

    2006-01-01

    In this activity, learners will test cups full of potting soil, sand, and sphagnum moss to see which earth material is able to soak up the most water. Using a scale and a simple calculation, learners can determine the amount of water held by a material, in reference to its original weight. Relates to the linked video, DragonflyTV GPS: Bogs.

  1. Radioactivity in building materials

    International Nuclear Information System (INIS)

    The present report, drawn up at the request of the former Minister of Public Health and Environmental Affairs of the Netherlands, discusses the potential radiological consequences for the population of the Netherlands of using waste materials as building materials in housing construction. (Auth.)

  2. Materials Science and Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.

    1993-03-01

    Five papers are included: processing/characterization of laminated metal composites, casting process modeling, characterizing the failure of composite materials, fiber-optic Raman spectroscopy for cure monitoring of advanced polymer composites, and modeling superplastic materials. The papers are processed separately for the data base.

  3. Dielectric material for dosimeters

    International Nuclear Information System (INIS)

    A RITAD dosimeter is described having a dielectric material such as sapphire wherein the efficiency as measured by mean drift distance and trapping efficiency is increased by making use of a dielectric material in which the total active impurity does not exceed 50 ppm and in which any one active impurity does not exceed 10 ppm

  4. Chromogenic smart materials

    Directory of Open Access Journals (Sweden)

    Carl M. Lampert

    2004-03-01

    Full Text Available Smart materials cover a wide and developing range of technologies. A particular type of smart material, known as chromogenics, can be used for large area glazing in buildings, automobiles, planes, and for certain types of electronic display. These technologies consist of electrically-driven media including electrochromism, suspended particle electrophoresis, polymer dispersed liquid crystals, electrically heated thermotropics, and gaschromics.

  5. Microporous and macroporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, R.F. [ed.] [Univ. of Delaware, Newark, DE (United States); Beck, J.S. [ed.] [Mobil Technology Co., Paulsboro, NJ (United States); Suib, S.L. [ed.] [Univ. of Connecticut, Storrs, CT (United States); Corbin, D.R. [ed.] [E.I. Dupont de Nemours and Co., Wilmington, DE (United States); Davis, M.E. [ed.] [California Inst. of Tech., Pasadena, CA (United States); Iton, L.E. [ed.] [Argonne National Lab., IL (United States); Zones, S.I. [ed.] [Chevron Research and Technology Co., Richmond, CA (United States)

    1996-12-31

    The 81 papers contained in this volume are arranged into the following topical sections: zeolites, clays, and microporous materials; mesoporous materials; methods of studying porosity; thin films and adsorption; sol-gel synthesis of metal oxides and nitrides; applications of porous metal oxides; porous semiconductors; and porous polymers. Most papers have been processed separately for inclusion on the database.

  6. Material Fatigue Testing System

    Science.gov (United States)

    Gilley, P. J. (inventor)

    1973-01-01

    A system for cyclicly applying a varying load to a material under test is described. It includes a load sensor which senses the magnitude of load being applied to a material, and, upon sensing a selected magnitude of loading, causes the load to be maintained for a predetermined time and then cause the system to resume cyclical loading.

  7. Impacted material placement plans

    International Nuclear Information System (INIS)

    Impacted material placement plans (IMPP) are documents identifying the essential elements in placing remediation wastes into disposal facilities. Remediation wastes or impacted material(s) are those components used in the construction of the disposal facility exclusive of the liners and caps. The components might include soils, concrete, rubble, debris, and other regulatory approved materials. The IMPP provides the details necessary for interested parties to understand the management and construction practices at the disposal facility. The IMPP should identify the regulatory requirements from applicable DOE Orders, the ROD(s) (where a part of a CERCLA remedy), closure plans, or any other relevant agreements or regulations. Also, how the impacted material will be tracked should be described. Finally, detailed descriptions of what will be placed and how it will be placed should be included. The placement of impacted material into approved on-site disposal facilities (OSDF) is an integral part of gaining regulatory approval. To obtain this approval, a detailed plan (Impacted Material Placement Plan [IMPP]) was developed for the Fernald OSDF. The IMPP provides detailed information for the DOE, site generators, the stakeholders, regulatory community, and the construction subcontractor placing various types of impacted material within the disposal facility

  8. INTEGRATED STEAMHYDROINSULATING MATERIAL / ??????????? ?????????????????????????? ????????

    Directory of Open Access Journals (Sweden)

    Sokov V. N. / ????? ?????? ??????????

    2014-10-01

    Full Text Available The authors develop the most sensible approach to the creation of a new effective multi-purpose bitumopolystyrene material on exposure of temperature, pressure and electric current. This method allows to create a dense structure of the material matrix, to receive strong adhesive contacts on the interface of bitumen / polystyrene in time of self-consolidation of goods / ?????????? ???????? ??????????? ?????? ? ???????? ?????? ???????????? ????????????????????? ????????? ???????????????????? ?????????? ??? ??????????? ???????????, ???????? ? ?????????????? ????, ??????? ????????? ??????????? ??????? ????????? ??????? ?????????, ???????? ??????? ??????????? ???????? ?? ??????????? ??????? «????? — ??????????» ??? ?????????????? ???????

  9. The Computational Materials Repository

    DEFF Research Database (Denmark)

    Landis, David D.; HummelshØj, Jens S.

    2012-01-01

    The possibilities for designing new materials based on quantum physics calculations are rapidly growing, but these design efforts lead to a significant increase in the amount of computational data created. The Computational Materials Repository (CMR) addresses this data challenge and provides a software infrastructure that supports the collection, storage, retrieval, analysis, and sharing of data produced by many electronic-structure simulators.

  10. Strongly correlated materials.

    Science.gov (United States)

    Morosan, Emilia; Natelson, Douglas; Nevidomskyy, Andriy H; Si, Qimiao

    2012-09-18

    Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO? and Fe?O?, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials. PMID:22893361

  11. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks are mentioned. References to review papers, papers with experimental data, and papers describing the thermodynamic modelling of the systems are given.

  12. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  13. Combinatorial materials synthesis

    Directory of Open Access Journals (Sweden)

    Ichiro Takeuchi

    2005-10-01

    Full Text Available The pace at which major technological changes take place is often dictated by the rate at which new materials are discovered, and the timely arrival of new materials has always played a key role in bringing advances to our society. It is no wonder then that the so-called combinatorial or high-throughput strategy has been embraced by practitioners of materials science in virtually every field. High-throughput experimentation allows simultaneous synthesis and screening of large arrays of different materials. Pioneered by the pharmaceutical industry, the combinatorial method is now widely considered to be a watershed in accelerating the discovery and optimization of new materials1–5.

  14. Reactor pressure boundary materials

    International Nuclear Information System (INIS)

    With a long-term operation of nuclear power plants, the component materials are degraded under severe reactor conditions such as neutron irradiation, high temperature, high pressure and corrosive environment. It is necessary to establish the reliable and practical technologies for improving and developing the component materials and for evaluating the mechanical properties. Especially, it is very important to investigate the technologies for reactor pressure boundary materials such as reactor vessel and pipings in accordance with their critical roles. Therefore, this study was focused on developing and advancing the microstructural/micro-mechanical evaluation technologies, and on evaluating the neutron irradiation characteristics and radiation effects analysis technology of the reactor pressure boundary materials, and also on establishing a basis of nuclear material property database

  15. High quality casting materials

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2010-11-01

    Full Text Available Purpose: The paper briefly presents results of the new developed high quality cast materials.Design/methodology/approach: The following materials are: hypereutectoid cast steel with various microstructure modular graphite obtained in as-cast condition (raw state, ductile cast iron of bainite-martensitic carbides structure obtained in a raw state, aluminum bronzes and silumins with additives of: chromium, molybdenum, wolfram, vanadium.Findings: These alloys are characterized primarily by significant mechanical properties and high wear resistance. It was also discussed getting of layer products by combination of steel or cast iron using alphinated layer with silumin.Practical implications: The paper discusses the high quality cast alloy, layer products and presents the high quality casting materials in the point of view principles of materials selection.Originality/value: The above problem is shown in the background of “Rules of material selection” as well as a model of production system in company.

  16. Magnetic material separation and high superconducting material

    International Nuclear Information System (INIS)

    Full text: Magnetic separation techniques provide an efficient method for the separation of very fine and weak magnetic materials, especially using a high gradient magnetic separator (HGMS). The separation efficiency is mainly related to the strength of the magnetic field applied and the field gradient generated to trap the magnetic particles (the magnetic force of a particle having volume V in magnetic field is described as Fm ?oV(?p-?m) H dH/dx). As a device, HGMS comprises essentially a canister containing a matrix of filamentary magnetic material, which is placed within a strong and relatively uniform magnetic field typically generated by a solenoid magnet, as shown HTS material has interesting relation with the magnetic separation techniques, especially HGMS, and can be summarised as follows: (1) HTS materials can be purified with magnetic separation techniques. This is because the HTS material (powder) has paramagnetic and diamagnetic transition at its critical temperature Tc. By using this method, powders with desired HTS phase can be obtained, e.g. the separation of Bi-2223 and 2212 components. (2) HTS can be used for the design of a matrix used in HGMS with high field gradient. HTS has the nature of quantum flux by unit ?o. The sample designed groups the flux and therefore forming the high gradient magnetic field required for the HGMS matrix. Considering superconductor flux jump stability {g superconductor flux jump stability {Bfj=(?/2)[?oCJc/(dJc/dT)]1/2 by Swart and Bean}, HTS has a much greater value (? 10 times) than LTS, e.g. Bfj YBaCuO is up to 14 T / 77 K (cal.); meanwhile Nb3Sn can only trap 0.9 T at 16 K. (3) HTS can generate high magnetic fields by: (a) HTS bulk can trap very high field, e.g. melt-textured YBaCuO brick having ? 1 T / 77 K; (b) HTS wire can produce high field magnet, e.g. magnet made by (Bi,Pb)2Sr2Ca2Cu3010+x Ag clad HTS wire can generate sufficient magnetic field at an economic operation temperature. HTS techniques provide some advantages to design a HGMS with higher separation efficiency. Magnet made by the (Bi,Pb)2Sr2Ca2Cu3O10+x Ag clad HTS wire is suitable to build a high efficiency HGMS which has widely applications

  17. Security of material

    International Nuclear Information System (INIS)

    Full text: From the early days of discovery and experimentation with nuclear science, nuclear and radioactive materials have held extraordinary potential for being of great benefit to humankind, as well as for causing significant harm. For the past forty years, the IAEA has played an important role in ensuring that nuclear technologies and materials are used only for peaceful purposes. The Agency's safeguards programme has been providing assurances that States honour their undertakings to use nuclear facilities and materials for peaceful purposes only. The potential of nuclear materials and other radioactive materials being used in subversive activities, such as theft, illicit trafficking, sabotage and threats thereof, has been recognized by the international community. The tragic events in New York have given new light to and increased concern for this potential. No target may be considered immune from terrorism. Since 1993, States have confirmed over 370 cases of illicit trafficking. Information is also available on potential attempts of and actual acts of sabotage. For any State, the first step in ensuring the security of their materials is an effective national system. Such a system must contain multiple elements, including physical protection measures, material accountability arrangements, reliable detection capabilities, and plans for rapid and effective response when material is found to be lost, stolen or otherwise not under proper control. The system must also cover illegal waste dumping and other activities that would result in the release of radioactive material into the environment. All these measures should be based on well founded legal and regulatory structures. In many cases, the responsibility for these various elements lies with different bodies, and co-operation between them is vital to the success of the national system. The Agency's programme Security of Material aims at being of service to States in their efforts to upgrade their security measures for nuclear and radioactive material - through the transfer of technology, exchange of information, assistance and training in the implementation of internationally accepted standards. The paper gives further details on present activities. It also looks into the Agency's process to review its programmes in the light of the request by the General Conference to the IAEA Director General to 'review thoroughly the activities and programmes of the Agency with a view to strengthening the Agency work relevant to preventing acts of terrorism involving nuclear materials and other radioactive materials' (GC(45)/RES/14). (author)

  18. High temperature materials

    International Nuclear Information System (INIS)

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  19. Consumo como cultura material

    Scientific Electronic Library Online (English)

    Miller, Daniel.

    2007-12-01

    Full Text Available Este artigo pretende considerar as conseqüências de se enxergar o consumo através das lentes dos estudos de cultura material contemporâneos. O artigo inicia reconhecendo as razões pelas quais o consumo é freqüentemente visto como a destruição da cultura material e portanto intrinsicamente maligno. E [...] m seguida explora as várias abordagens disciplinares ao consumo, tal como da história e sociologia, antes de se concentrar na antropologia e em diversas perspectivas regionais. Ele então explora abordagens mais específicas oriundas dos estudos de cultura material, primeiro teoricamente, e em seguida substantivamente, em termos de quatro gêneros: a casa, vestuário, a mídia e o carro. Dois interesses mais amplos seguem, o da análise da cadeia de commodities e da relação geral entre pessoas e coisas. O artigo conclui que, ao invés de promover o materialismo, uma perspectiva de cultura material enfatiza o quanto o consumo pode ser usado para entender a nossa humanidade. Abstract in english This article is aimed to consider the consequences of viewing consumption through the lens of contemporary material culture studies. It starts by acknowledging the reasons consumption is often seen as the destruction of material culture and therefore intrinsically evil. It then explores various disc [...] iplinary approaches to consumption such as history and sociology before concentrating on anthropology and various regional perspectives. It then explores more specific approaches from material culture studies, first theoretically, and then substantively in terms of four genres of home, clothing the media and the car. Two broader concerns follow, that of commodity chain analysis and the general relationship between persons and things. It concludes that so far from promoting materialism, a material culture perspective emphasis how consumption can be used to understand our humanity.

  20. Thermal fatigue. Materials modelling

    International Nuclear Information System (INIS)

    In the framework of the ongoing joint research project 'Thermal Fatigue - Basics of the system-, outflow- and material-characteristics of piping under thermal fatigue' funded by the German Federal Ministry of Education and Research (BMBF) fundamental numerical and experimental investigations on the material behavior under transient thermal-mechanical stress conditions (high cycle fatigue V HCF and low cycle fatigue - LCF) are carried out. The primary objective of the research is the further development of simulation methods applied in safety evaluations of nuclear power plant components. In this context the modeling of crack initiation and growth inside the material structure induced by varying thermal loads are of particular interest. Therefore, three scientific working groups organized in three sub-projects of the joint research project are dealing with numerical modeling and simulation at different levels ranging from atomistic to micromechanics and continuum mechanics, and in addition corresponding experimental data for the validation of the numerical results and identification of the parameters of the associated material models are provided. The present contribution is focused on the development and experimental validation of material models and methods to characterize the damage evolution and the life cycle assessment as a result of thermal cyclic loading. The individual purposes of the subprojects are as following: - Material characterization, Influence of temperature and surface roughness on fatigue endurances, biaxial thermo-mechanical behavior, experiments on structural behavior of cruciform specimens and scatter band analysis (IfW Darmstadt) - Life cycle assessment with micromechanical material models (MPA Stuttgart) - Life cycle assessment with atomistic and damage-mechanical material models associated with material tests under thermal fatigue (Fraunhofer IWM, Freiburg) - Simulation of fatigue crack growth, opening and closure of a short crack under thermal cyclic loading conditions, developing methods for the damage assessment based on the cyclic J-integral (IFSW Darmstadt, AREVA) - Further development of plasticity models (IFSW Darmstadt, AREVA) Within this paper the various investigations and the main results are presented.

  1. Professional Nuclear Materials Management

    International Nuclear Information System (INIS)

    This paper describes the scope of nuclear materials management for a typical power reactor in the United States of America. Since this power reactor is financed by private capital, one of the principal obligations of the reactor operator is to ensure that the investment is protected and will furnish an adequate financial return. Because of the high intrinsic value of nuclear materials, appropriate security and accountability must be continually exercised to minimize losses beyond security and accountability for the nuclear materials. Intelligent forethought and planning must be employed to ensure that additional capital is not lost as avoidable additional costs or loss of revenue in a number of areas. The nuclear materials manager must therefore provide in advance against the following contingencies and maintain constant control or liaison against deviations from planning during (a) pre-reactor acquisition of fuel and fuel elements, (b) in-reactor utilization of the fuel elements, and (c) post-reactor recovery of fuel values. During pre-reactor planning and operations, it is important that the fuel element be designed for economy in manufacture, handling, shipping, and replaceability. The time schedule for manufacturing operations must minimize losses of revenue from unproductive dead storage of high cost materials. For in-reactor operations, the maximum achievable burn-up of the fissionable material must be obtained by means of appropriate fuel rearrangement schemes.of appropriate fuel rearrangement schemes. Concurrently the unproductive down-time of the reactor for fuel rearrangement, inspections, and the like must be minimized. In the post-reactor period, when the fuel has reached a predetermined depletion of fissionable material, the nuclear materials manager must provide for the most economical reprocessing and recovery of fissionable values and by-products. Nuclear materials management is consequently an essential factor in achieving competitive fuel cycle and unit energy costs with power reactors. (author)

  2. Solid breeder materials

    International Nuclear Information System (INIS)

    Increased attention is being given to the consideration of lithium-containing ceramic materials for use as breeder blankets in fusion devices. These materials, e.g., Li2O, #betta#-LiAlO2, Li4SiO4, Li2ZrO3, etc., are attractive because of their inherent safety advantages. At present, there is a broad scope of laboratory and irradiation activities in force to provide the requisite data enabling selection of th prime-candidate solid breeder material

  3. Minerals as advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Depmeier, W. [Universitaet Kiel (Germany). Institut fuer Geowissenschaften, Kristallographie-Mineralogie

    2009-10-15

    A resume is given on relationships between minerals and materials. It is shown that Nature has many advantages over technology which can be profitably exploited for finding new materials with useful properties. However, Nature has also inherent limitations. Therefore, it seems advisable to use the knowledge of minerals as a treasure which can be tapped for getting inspired on the way to finding new materials. Several examples are given, including those of zorite/ETS-4/ETS-10, boracites, zircon, kesterite, a natural quasicrystal, opals, ultramarine and mayenite. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Structural materials for NASP

    Science.gov (United States)

    Ronald, Terence M. F.

    1991-12-01

    Structural materials for the NASP X-30 experimental vehicle are briefly reviewed including titanium alloys, titanium-based metal-matrix composites, carbon-carbon composites, ceramic-matrix composites, and copper-matrix composites. Areas of application of these materials include the airframe where these materials would be used as lightweight skin panels for honeycomb-core, truss-core, or integrally stiffened thin sheet configuration; and the engine, where they would be used in the hot gas path of the ramjet/scramjet, and in the inlet and nozzle areas.

  5. Radiation absorbing plane material

    International Nuclear Information System (INIS)

    The invention has been aimed at a radiation absorbing plane material preferably applicable to X-ray technique and nuclear medicine. This material has a good adaptibility to different body surfaces and allows a layer thickness variance from 5 to 100 ?m. The plane material has been composed of at least one radiation transparent layer, one radiation absorbing layer, and further auxiliary layers if necessary. The radiation absorbing layer consists of a pigment loaded fibre-nonwoven textile fabric (paper or fleece) and/or a pigment binding system

  6. RADIOACTIVE MATERIALS SENSORS

    International Nuclear Information System (INIS)

    Providing technical means to detect, prevent, and reverse the threat of potential illicit use of radiological or nuclear materials is among the greatest challenges facing contemporary science and technology. In this short article, we provide brief description and overview of the state-of-the-art in sensor development for the detection of radioactive materials, as well as an identification of the technical needs and challenges faced by the detection community. We begin with a discussion of gamma-ray and neutron detectors and spectrometers, followed by a description of imaging sensors, active interrogation, and materials development, before closing with a brief discussion of the unique challenges posed in fielding sensor systems.

  7. Investigating Encrypted Material

    Science.gov (United States)

    McGrath, Niall; Gladyshev, Pavel; Kechadi, Tahar; Carthy, Joe

    When encrypted material is discovered during a digital investigation and the investigator cannot decrypt the material then s/he is faced with the problem of how to determine the evidential value of the material. This research is proposing a methodology of extracting probative value from the encrypted file of a hybrid cryptosystem. The methodology also incorporates a technique for locating the original plaintext file. Since child pornography (KP) images and terrorist related information (TI) are transmitted in encrypted format the digital investigator must ask the question Cui Bono? - who benefits or who is the recipient? By doing this the scope of the digital investigation can be extended to reveal the intended recipient.

  8. Materials for Fusion Applications.

    Czech Academy of Sciences Publication Activity Database

    Mat?jí?ek, Ji?í

    2013-01-01

    Ro?. 53, ?. 2 (2013), s. 197-212. ISSN 1210-2709. [Symposium on Plasma Physics and Technology/25./. Praha, 18.06.2012-21.06.2012] R&D Projects: GA ?R(CZ) GAP108/12/1872; GA MŠk 7G10072 Institutional research plan: CEZ:AV0Z20430508 Keywords : nuclear fusion * material s * plasma facing components * plasma- material interaction * functionally graded material s Subject RIV: BL - Plasma and Gas Discharge Physics http://ctn.cvut.cz/ap/download.php?id=797

  9. Hydrogen bonded supramolecular materials

    CERN Document Server

    Li, Zhan-Ting

    2015-01-01

    This book is an up-to-date text covering topics in utilizing hydrogen bonding for constructing functional architectures and supramolecular materials. The first chapter addresses the control of photo-induced electron and energy transfer. The second chapter summarizes the formation of nano-porous materials. The following two chapters introduce self-assembled gels, many of which exhibit unique functions. Other chapters cover the advances in supramolecular liquid crystals and the versatility of hydrogen bonding in tuning/improving the properties and performance of materials. This book is designe

  10. Materials science and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Holden, T.M.

    1995-10-01

    The science-based stockpile stewardship program emphasizes a better understanding of how complex components function through advanced computer calculations. Many of the problem areas are in the behavior of materials making up the equipment. The Los Alamos Neutron Science Center (LANSCE) can contribute to solving these problems by providing diagnostic tools to examine parts noninvasively and by providing the experimental tools to understand material behavior in terms of both the atomic structure and the microstructure. Advanced computer codes need experimental information on material behavior in response to stress, temperature, and pressure as input, and they need benchmarking experiments to test the model predictions for the finished part.

  11. Optical materials and applications

    CERN Document Server

    Wakaki, Moriaki; Kudo, Keiei

    2012-01-01

    The definition of optical material has expanded in recent years, largely because of IT advances that have led to rapid growth in optoelectronics applications. Helping to explain this evolution, Optical Materials and Applications presents contributions from leading experts who explore the basic concepts of optical materials and the many typical applications in which they are used. An invaluable reference for readers ranging from professionals to technical managers to graduate engineering students, this book covers everything from traditional principles to more cutting-edge topics. It also detai

  12. Polymer material biodegradation

    Directory of Open Access Journals (Sweden)

    B. Grabowska

    2010-04-01

    Full Text Available Data from literature was used to discuss the impact of external factors (stress, radiation, temperature, ultrasounds, biological organisms on the course of polymer material degradation. Polymer materials, in widespread use for over a dozen years, constitute a serious environmental problem. This is why their susceptibility to biodegradation is researched. Work on biodegradable polymers concernsmodifying their structure to bring their physical and chemical properties closer to plastics in practical use or using biodegradable polymers as an alternative for the current conventional materials. In addition, the publication also presents the first results of work on the biodegradation of polymer foundry binders.

  13. THERMALLY CLEAVABLE HYBRID MATERIALS

    Directory of Open Access Journals (Sweden)

    Constantin Gaina

    2011-12-01

    Full Text Available Thermally cleavable hybrid materials were prepared by the Diels-Alder cycloaddition reaction of poly(vinyl furfural to N phenylmaleimido-N’-(triethoxysilylpropylurea followed by the sol-gel condensation reaction of trietoxysilyl groups with water and acetic acid. Thermal and dynamic mechanical analysis, dielectric and FTIR spectroscopy were used to characterize the structure and properties of the composites. The size of the inorganic silica particles in the hybrid material varied dependent on the silica content. The DSC study of the prepared materials revealed that the cleavage process of the formed cycloadducts takes place at temperatures varying between 143-165°C and is an endothermic process.

  14. Fusion Reactor Materials

    International Nuclear Information System (INIS)

    SCK-CEN's research and development programme on fusion reactor materials includes: (1) the study of the mechanical behaviour of structural materials under neutron irradiation (including steels, inconel, molybdenum, chromium); (2) the determination and modelling of the characteristics of irradiated first wall materials such as beryllium; (3) the detection of abrupt electrical degradation of insulating ceramics under high temperature and neutron irradiation; (4) the study of the dismantling and waste disposal strategy for fusion reactors.; (5) a feasibility study for the testing of blanket modules under neutron radiation. Main achievements in these topical areas in the year 1999 are summarised

  15. Conducting polymer materials

    Directory of Open Access Journals (Sweden)

    Jovanovi? Slobodan M.

    2003-01-01

    Full Text Available Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a conducting polymers the conductivity of which is the result of their molecular structure, and b conducting polymer composites (EPC, is given in this paper. The applications and future development of this group of polymer materials is also discussed.

  16. Materials at LANL

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Antoinette J [Los Alamos National Laboratory

    2010-01-01

    Exploring the physics, chemistry, and metallurgy of materials has been a primary focus of Los Alamos National Laboratory since its inception. In the early 1940s, very little was known or understood about plutonium, uranium, or their alloys. In addition, several new ionic, polymeric, and energetic materials with unique properties were needed in the development of nuclear weapons. As the Laboratory has evolved, and as missions in threat reduction, defense, energy, and meeting other emerging national challenges have been added, the role of materials science has expanded with the need for continued improvement in our understanding of the structure and properties of materials and in our ability to synthesize and process materials with unique characteristics. Materials science and engineering continues to be central to this Laboratory's success, and the materials capability truly spans the entire laboratory - touching upon numerous divisions and directorates and estimated to include >1/3 of the lab's technical staff. In 2006, Los Alamos and LANS LLC began to redefine our future, building upon the laboratory's established strengths and promoted by strongly interdependent science, technology and engineering capabilities. Eight Grand Challenges for Science were set forth as a technical framework for bridging across capabilities. Two of these grand challenges, Fundamental Understanding of Materials and Superconductivity and Actinide Science. were clearly materials-centric and were led out of our organizations. The complexity of these scientific thrusts was fleshed out through workshops involving cross-disciplinary teams. These teams refined the grand challenge concepts into actionable descriptions to be used as guidance for decisions like our LDRD strategic investment strategies and as the organizing basis for our external review process. In 2008, the Laboratory published 'Building the Future of Los Alamos. The Premier National Security Science Laboratory,' LA-UR-08-1541. This document introduced three strategic thrusts that crosscut the Grand Challenges and define future laboratory directions and facilities: (1) Information Science and Technology enabl ing integrative and predictive science; (2) Experimental science focused on materials for the future; and (3) Fundamental forensic science for nuclear, biological, and chemical threats. The next step for the Materials Capability was to develop a strategic plan for the second thrust, Materials for the Future. within the context of a capabilities-based Laboratory. This work has involved extending our 2006-2007 Grand Challenge workshops, integrating materials fundamental challenges into the MaRIE definition, and capitalizing on the emerging materials-centric national security missions. Strategic planning workshops with broad leadership and staff participation continued to hone our scientific directions and reinforce our strength through interdependence. By the Fall of 2008, these workshops promoted our primary strength as the delivery of Predictive Performance in applications where Extreme Environments dominate and where the discovery of Emergent Phenomena is a critical. These planning efforts were put into action through the development of our FY10 LDRD Strategic Investment Plan where the Materials Category was defined to incorporate three central thrusts: Prediction and Control of Performance, Extreme Environments and Emergent Phenomena. As with all strategic planning, much of the benefit is in the dialogue and cross-fertilization of ideas that occurs during the process. By winter of 2008/09, there was much agreement on the evolving focus for the Materials Strategy, but there was some lingering doubt over Prediction and Control of Performance as one of the three central thrusts, because it overarches all we do and is, truly, the end goal for materials science and engineering. Therefore, we elevated this thrust within the overarching vision/mission and introduce the concept of Defects and Interfaces as a central thrust that had previously been implied but

  17. Glossaries and Reference Material

    Science.gov (United States)

    Updated: October 5, 2010 Updated: October 5, 2010 Glossaries and Reference Material Glossary of Cancer Statistics Definitions of common terms, NCI terminology, and the five key statistical measures of cancer: incidence, mortality, survival, prevalence,

  18. Moldable cork ablation material

    Science.gov (United States)

    1977-01-01

    A successful thermal ablative material was manufactured. Moldable cork sheets were tested for density, tensile strength, tensile elongation, thermal conductivity, compression set, and specific heat. A moldable cork sheet, therefore, was established as a realistic product.

  19. Intelligent Radiative Materials Project

    National Aeronautics and Space Administration — An opportunity to boost energy efficiency in homes and buildings exists through the design of functional radiative properties in glass and other building materials....

  20. Nuclear material operations manual

    International Nuclear Information System (INIS)

    This manual is intended to provide a concise and comprehensive documentation of the operating procedures currently practiced at Sandia Laboratories with regard to the management, control, and accountability of radioactive and nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations--management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of ''play-scripts'' in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion