Sample records for araldite


    Directory of Open Access Journals (Sweden)



    Full Text Available Flammability characteristics of araldite based composite mixed with inorganic hybrid flame retardant represent zinc borate - antimony trioxide as a surface layer(4mm thickness have been studied by thermal erosion test . Antimony trioxide was added to zinc borate with various amounts (10%,20% and 30% to forming a hybrid flame retardant for enhance the action of this material to react flame . The result composite material was exposed to a direct flame generated from Oxyacetylene torch (3000ºC with different flame exposure intervals (10,20mm, and studies the range of resistance of retardant material layer to the flames and protected the substrate. The optimum results were with large percentage from protective layer which is zinc borate-30% antimony trioxide and large exposed distance.

  2. Stability of transition temperatures in certain irradiated araldites

    International Nuclear Information System (INIS)

    Transition temperatures (Tsub(g)) of six different araldite-hardener specimens are determined by the ultrasonic rotating plate method, before and after irradiating the specimens up to saturation by thermal neutrons. The results indicate that the stability of Tsub(g) on irradiation is more in the unmodified resins than in the plasticized ones. Specimens of plasticized resin, when cured at higher temperatures are found to show higher stability of Tsub(g) than the specimens cured at lower temperatures. Epoxy resins originally exhibiting high values of Tsub(g) are found to possess high stability of Tsub(g) in the radiation field and hence radiation resistant. This result is in consonance with the reports in literature that high heat resistant epoxy compounds are also highly radiation resistant. (author)

  3. Studies on an araldite-based membrane of copper hexacyanoferrate (III) as a caesium ion-sensitive electrode

    International Nuclear Information System (INIS)

    Solid membranes of copper hexacyanoferrate (III) in araldite are evaluated as a caesium ion-sensitive electrode. The electrode can be used for caesium determination in the concentration range of 10-1 to 10-4M. The potentials generated across the membrane are reproducible and steady potentials are attained in about 1 to 2 min. The same electrode can be used over a period of 6 months without significant change in potential. The electrode can be used in the pH ranges 2.5 to 6.0 at 10-2M Cs+ and 3.0 to 6.0 at 10-3M Cs+, and in presence of a number of interfering ions. Potentiometric titration of caesium nitrate with 12-molybdophosphoric acid was also carried out using the membrane as an end point indicator. (author)

  4. Characteristics and fabrication of Geiger-Mueller counters with thin walls made of treated magnesium - Note about the use of araldite

    International Nuclear Information System (INIS)

    This report describes, first, the advantage of magnesium for the manufacturing of Geiger-Mueller counters: suitable for machining and polishing, but strong reactivity with the counter atmosphere in the case of magnesium-rich alloys. Thus, the inside wall of the counter (cylinder of 20 mm diameter and 6 cm length) requires a non-reactive protective coating with excellent sealing properties. The synthetic resin 'araldite' fulfills all these conditions. The second part of the report describes the different steps of the fabrication of magnesium wall counters: lathe work, machining down and chemical polishing of hulls, assembly, tight sealing, pumping, filling-up and control tests. The average service life of these counters is of about 4 months. A note about the use and properties (hardening, mechanical properties, resistance..) of araldite is given in appendix. (J.S.)

  5. Numerical simulation of impact bend tests on araldite B and steel specimens

    International Nuclear Information System (INIS)

    As a preliminary stage in the numerical simulation of impact bend tests on elastic-plastic sample materials some simpler experiments were calculated for this report, some of which occured without crack propagation, others with linear elastic crack propagation. These calculations were performed with an own program based on the method of finite differences and also with the finite element program ADINA. In the numerical models plane stress was assumed. Crack propagation was governed by a relation between crack velocity and stress intensity factor. As load input the measured hammer load was used in some cases, mass and initial velocity of the hammer in others. The sample looses contact to the anvils and to the hammer for some time, which had to be considered in model building. The stiffening of the model in the contact region caused by the discretization had to be compensated by springs inserted between the sample and the anvils. The simulation reproduces the experimentally observed behaviour of the sample quite well. Furthermore, additional information can be extracted from the experiment, e.g. concerning the partition of the impact energy. (orig.)

  6. Morphology of the human internal vertebral venous plexus : a cadaver study after intravenous Araldite CY 221 injection

    NARCIS (Netherlands)

    Groen, R J; Groenewegen, H J; van Alphen, H A; Hoogland, P V


    Reviewing the literature on the vascular anatomy of the spinal epidural space, it appeared that the knowledge of the internal vertebral venous plexus is limited. Injection studies of the entire internal vertebral venous plexus after application of modern techniques, to the best of our knowledge, hav

  7. Preservation of the diffusible cations for secondary ion mass spectrometry. II. Artefacts in material embedded in araldite or melamine. (United States)

    Mentré, P; Escaig, F


    Flotation on hot water (about 60 degrees C) which is frequently employed to stretch semithin sections on substrates for SIMS (secondary ion mass spectrometry) microscopy, is the cause of numerous artefacts. In the case of epoxy resin-embedded tissue, one observes loss of potassium and sodium and accumulation of calcium. The relative contrast of cell nuclei in the ionic images, is rapidly affected by these ion migrations. After prolonged contact with hot water, tissue becomes uniformly emissive. In the case of hydrosoluble resin-embedded tissue, potassium and sodium do not appear to be affected by the action of water, which suggests that they are covalently bound with chelating sites buried beneath the layer of water bound to the surface of the macromolecules. Calcium accumulates, probably on widely exposed anionic sites. Moreover, the domains observed in hydrosoluble resin-embedded tissue shrink differently according to the proportion of water removed by melamine; this can provide interesting information on the initial equilibrium between water, ion sand macromolecules. Our results seem to support the assumption that bound water should play an important role in the preservation of both macromolecular architecture and ion distributions. PMID:1511241

  8. Comparative study of anatomical specimens using plastination by araldite HY103, polypropylene resin, 6170H19 Orthocryl and silicone – A qualitative study (United States)

    Pandit, Subhendu; Kumar, Sushil; Mishra, B.K.


    Background Most of the organs and tissues are preserved in formalin with its own set of disadvantages. Plastination is a unique method of permanently preserving tissue in a life like state. Plastination developed by western authorities is a labour and equipment intensive affair. Most common polymer used is S10, however this study uses easily available alternative polymers for plastination. Method Various polymers like Epoxy resins, Polypropylene resins, Orthocryl and silicone were used in plastinating the anatomical specimens. Specific methods were used for solid, hollow organs and brain specimens. The specimens were made to undergo stages of fixation, dehydration, impregnation and curing. The results were studied and interpreted under various parameters. Results The results were interpreted under various parameters like shrinkage, retention of colour, odour, pliability and retention of gross anatomy. The study concluded that Orthocryl and Epoxy resins retained maximum colour with minimal shrinkage while maximum discolouration was with polypropylene plastinates. Brain sections were best preserved in Orthocryl. Conclusion The study concluded that indigenous methods and materials can produce quality plastinates which can be an important adjunct to traditional methods of teaching however more studies need to be done for refinement. PMID:26288492

  9. Re-examination of the dielectric spectra of epoxy resins: Bulk charge transport and interfacial polarization peaks


    Chalashkanov, N. M.; Dodd, S J; Dissado, L. A.; Fothergill, J


    The dielectric properties of two amine cured bisphenol-A epoxy resin systems, Araldite CY1301 and Araldite CY1311 have been characterized using dielectric spectroscopy over the frequency range 1 mHz to 100 kHz. These two epoxy resin systems were chosen to allow the dielectric response to be studied from above and below the glass transition, as Araldite CY1311 is a modified version (with added plasticizer) of Araldite CY1301. The dielectric response was found to comprise both bulk and interfac...

  10. Influence of absorbed moisture on the dielectric properties of epoxy resins


    Dodd, S J; Chalashkanov, N. M.; Dissado, L. A.; Fothergill, J


    The dielectric response of two bisphenol-A epoxy resin systems Araldite CY1301 (Tg ~ 50°C) and Araldite CY1311 (Tg ~0°C) was studied at different levels of absorbed moisture. The dielectric measurements were carried out over the frequency range 1 mHz to 100 kHz and the results were characterised in terms of dc bulk electrical conduction and dielectric processes. The characteristic parameters (frequency and magnitude) of all processes have been found to be moisture dependent. In both resins ab...

  11. The Thermal and Mechanical Properties of Glues for the ATLAS SCT ModuleAssembly

    CERN Document Server

    Kholodenko, A G; Riadovikov, VN


    We perform measurements of $C_{kt}-$the coefficient of thermal conductivityof two types of glue proposed for using in mechanical structureof the SCT modules of ATLAS .We compare the thermal property of thecommonly used electronic industry applications glue familyARALDITE and $Si-organic$ glue ``ELASTOSIL 137-182'' .The coefficients of the thermal conductivity for Boron nitride filled ARALDITE 1102 and ELASTOSIL 137-182 are presented. The value of the strength at tension was tested. The main results of the our tests are in agreement withvalues specified by manufacturer.

  12. S-HCEP——一种新的低成本合成绝缘子材料%Shed Hydrophobic Cycloaliphatic Epoxy (S-HCEP)- a New Cost-efficient Housing Material for Composite Insulators

    Institute of Scientific and Technical Information of China (English)


    Araldite S-HCEP, a new cost-efficient alternative housing material for composite insulators is briefly presented. Main topics of this paper are the results of two new studies on this material:①UV-weathering resistance in terms of hydrophobicity, roughness increase, surface resistance and flexibility. ②Leakage current behavior under salt fog conditions in comparison to other materials.

  13. Development of graphite-polymer composites as electrode materials

    Directory of Open Access Journals (Sweden)

    Carolina Maria Fioramonti Calixto


    Full Text Available Graphite powder was mixed to polyurethane, silicon rubber and Araldite® (epoxy in order to prepare composite materials to be used in the preparation of electrodes. Results showed that voltammetric response could be obtained when at least 50% of graphite (w.w-1 is present in the material. SEM and thermogravimetry were also used in the characterization of the composites.

  14. Hygrothermal Degradation Studies on E-Glass Woven Rovings-Epoxy Composite


    Guduru Mahendra1; K.Srividya2 ,


    In the present work, the property degradation of the selected material (i.e. E-glass & epoxy resin composite) manufactured by compression molding was investigated as a function of temperature after direct wetting in saline medium for varying periods. For the preparation of composite specimen, ARADUR HY951 used as hardener with ARALDITE LY556. From the experiment, moisture gain trends for different temperatures which vary with time. In that, hot setting laminate having good str...

  15. Ultrastrucmturaiml munogold labelling of vimentin filaments on postembedding ultrathin sections of arachnoid villi and meningiomas


    Yamashima, Tetsumori; Tachibana, Osamu; Nitta, Hisashi; Yamaguchi, Narihito; Yamashita, Junkoh


    An immunoelectron microscopic technique for the labelling of vimentin intermediate filaments on postembedding ultrathin sections is reported. Arachnoid villi obtained at autopsy and meningiomas at surgery were fixed in 1% paraformaldehyde for 30 minutes, embedded without postfixation in Epon-Araldite mixture and polymerized at 37OC for 3 weeks. Ultrathin sections were etched in 2% KOH for 3 minutes and incubated with anti-vimentin monoclonal antibodies whic...

  16. Thermal Characterization and Optimization of the Pixel Module Support Structure for the Phase-1 Upgrade of the CMS Pixel Detector

    CERN Document Server

    Rauch, Max Philip


    article/pii/0011747168900570, accessed on 7/21/2015.[38] Torayca, T300 Data Sheet,, accessedon 8/12/2015.[39] Araldite, Araldite Standard,, accessed on 6/19/2015.[40] S. Streuli, Paul-Scherrer-Institut (Villigen, Switzerland), private communication.[41] KERAFOL, Keratherm Thermal Grease: KP 98,, accessed on 6/19/2015.[42] K. Klein, 1. Physikalisches Institut B, RWTH Aachen, private communication.[43] COMSOL Multiphysics R Modeling Software,, accessed on 7/28/2015.[44] COMSOL Multiphysics R Heat Transfer Software,, accessed on 28.7.2015.[45] Picture taken from, accessed on 7/28/2015.[46] Mitsubishi Chemical, Dialead, K13D2U,, accessed on 7/29/2015.[47] Tenc...

  17. Influence of water absorption in flexible epoxy resins on the space charge behaviour


    Chalashkanov, N. M.; Dodd, S J; Fothergill, J


    The aim of the current work is to achieve a better understanding of the influence of water uptake in flexible epoxy resins on the space charge dynamics at high electric fields. The space charge behaviour was studied using pulsed electroacoustic (PEA) technique. The samples were prepared from Araldite CY1311, which is a bisphenol-A epoxy resin. This particular resin was chosen because its glass transition is 0°C and hence it is in a flexible state at room temperature. All samples were conditio...

  18. A Brazilian disk test for the evaluation of the shear strength of epoxy-joined ceramics

    International Nuclear Information System (INIS)

    Brazilian disk test is here analyzed as a test method to determine the strength of joined ceramics. The test specimen consisted of two silicon carbide half-disks diametrically bonded with a brittle adhesive (Araldite AV119 (TM)). Several tests were performed with different angles of the adhesive layer with respect to the diametral line of loading. An elastic finite element analysis is used to determine the maximum shear stress and the normal compressive stress within the joint. Assuming a failure criterion based on a shear stress condition, this procedure allows evaluating the shear strength of the epoxy adhesive. (authors)

  19. Optical self-sensing of impact damage in composites using E-glass cloth (United States)

    Rauf, A.; Hand, R. J.; Hayes, S. A.


    Self-sensing of damage in composites employs the reinforcing fibres as the sensing element, obviating the need for addition of sensing elements to the system. Optical self-sensing systems in the past have relied on the use of low refractive index resins in order to work, preventing the use of commercial laminating resins. In this study a commercial laminating resin (Araldite LY5052/Aradur HY5052) is modified with propylene carbonate, a commercial reactive diluent, to reduce the resin’s refractive index. It is shown that this system is capable of identifying and locating an impact and quantifying the extent of damage within a composite.

  20. Optical self-sensing of impact damage in composites using E-glass cloth

    International Nuclear Information System (INIS)

    Self-sensing of damage in composites employs the reinforcing fibres as the sensing element, obviating the need for addition of sensing elements to the system. Optical self-sensing systems in the past have relied on the use of low refractive index resins in order to work, preventing the use of commercial laminating resins. In this study a commercial laminating resin (Araldite LY5052/Aradur HY5052) is modified with propylene carbonate, a commercial reactive diluent, to reduce the resin’s refractive index. It is shown that this system is capable of identifying and locating an impact and quantifying the extent of damage within a composite. (paper)

  1. Preventing, monitoring and curing the ageing in the LHCb Outer Tracker

    CERN Document Server

    Visser, Erwin Lourens; Bethlem, H L


    The modules of the LHCb Outer Tracker have shown to suffer from gain loss under irradiation at moderate intensities, a process known as ageing. The plastifier in the glue with which the detector modules were constructed, Araldite AY103-1, has been shown to be the culprit. In this thesis this is confirmed by irradiating a module constructed with Araldite AY105-1, which does not contain the harmful plastifier. Several methods to prevent and repair the gain loss exist. One preventive measure is the addition of oxygen. However, because of its electronegative nature, oxygen can capture some of the drifting electrons, thereby lowering the gain of the OT. Simulations have been done to investigate the effect of oxygen on the gain and efficiency. One method to remove the ageing is HV training. In this procedure the applied voltage is increased such, that the OT enters the discharge regime. These discharges mostly remove the ageing, but can take place anywhere in the straw tube, not necessarily at the location of the a...

  2. 改性CVC织物涂料轧染工艺研究%Research on Pigment Pad Dyeing Process of Modified CVC Fabric

    Institute of Scientific and Technical Information of China (English)

    高亚宁; 谢永萍


    A new pigment padding process was explored on the basis of modified CVC fabric treated by self-made cationic modification agent. The dosages of adhesive and crosslinking agent, the curing temperature and time were optimized to obtain higher K/S value and color fastness to washing and rubbing. The results showed that the optimum condition was as follows:pigment 6 g/L, binder DH-103 15 g/L, Araldite PT810 crosslinking agent 10 g/L, curing at 180℃for 3 min.%  本文在采用自制阳离子改性剂对CVC织物改性的基础上,探索研究了新型涂料轧染工艺.通过对涂料轧染中粘合剂、交联剂用量以及焙烘温度和时间的优化,获得了较高的K/S值和耐皂洗、耐摩色牢度.优化后的工艺条件为涂料6 g/L,粘合剂DH-103用量15 g/L,Araldite PT810交联剂10 g/L,180℃焙烘3 min.

  3. Sound attenuation in magnetorheological fluids (United States)

    Rodríguez-López, J.; Elvira, L.; Resa, P.; Montero de Espinosa, F.


    In this work, the attenuation of ultrasonic elastic waves propagating through magnetorheological (MR) fluids is analysed as a function of the particle volume fraction and the magnetic field intensity. Non-commercial MR fluids made with iron ferromagnetic particles and two different solvents (an olive oil based solution and an Araldite-epoxy) were used. Particle volume fractions of up to 0.25 were analysed. It is shown that the attenuation of sound depends strongly on the solvent used and the volume fraction. The influence of a magnetic field up to 212 mT was studied and it was found that the sound attenuation increases with the magnetic intensity until saturation is reached. A hysteretic effect is evident once the magnetic field is removed.

  4. System for the identification of objects, for example nuclear fuel elements

    International Nuclear Information System (INIS)

    This invention provides a system for identifying objects (eg. fuel rods) or providing an indication of tampering with the objects which consists of a hollow body adopted for attachment to an object, a matrix material such as 'ARALDITE' or aluminum with inclusions in a random configuration. The inclusions may be a mixture of bronze or tungsten or voids and at least one must be a piezoelectric transducer. The transducer(s) on connection to an exterior ultrasonic testing apparatus will provide an output indicative of the structure of the seal and particularly the configuration of the various inclusions. Tampering with the seal or removal of the cap will alter its structure so subsequent testing will produce a different result indicating the occurrence of such an unauthorized event

  5. Study of thermal and mechanical properties of silica cloth reinforced HTPB modified epoxy composites

    International Nuclear Information System (INIS)

    Diglycidyl ether of bisphenol A modified with hydroxy terminated polybutadiene containing 1%, 5%, 7% and 10% HTPB was used as a matrix for the preparation of epoxy silica composites. HTPB was used as impact modifier for DGEBA. Thermal and Mechanical properties of neat epoxy silica composites and HTPB modified epoxy silica composites were compared with the neat and HTPB modified epoxy resins cured with Araldite 2011 B (N-3-Dimethylaminopropyl)-1,3-propylene diamine hardener. All the samples were characterized by FTIR, TGA and DMA techniques. Chemical incorporation of HTPB in epoxy matrix produced flexibility in the finally cured epoxy formulations. Epoxy formulations containing higher concentration of HTPB had lower moduli (E', E' and E*) and were more flexible. The moduli (E', E' and E*) of HTPB modified epoxy silica composites increased with the increase in the concentration of HTPB in the matrix. (author)

  6. Application of bioethanol derived lignin for improving physico-mechanical properties of thermoset biocomposites. (United States)

    Bajwa, Dilpreet S; Wang, Xinnan; Sitz, Evan; Loll, Tyler; Bhattacharjee, Sujal


    Lignin is the most abundant of renewable polymers next to cellulose with a global annual production of 70million tons, largely produced from pulping and second generation biofuel industries. Low value of industrial lignin makes it an attractive biomaterial for wide range of applications. The study investigated the application of wheat straw and corn stover based lignin derived from ethanol production for use in thermoset biocomposites. The biocomposite matrix constituted a two component low viscosity Araldite(®)LY 8601/Aradur(®) 8602 epoxy resin system and the lignin content varied from 0 to 25% by weight fraction. The analysis of the physical and mechanical properties of the biocomposites show bioethanol derived lignin can improve selective properties such as impact strength, and thermal stability without compromising the modulus and strength attributes. PMID:27131732

  7. Quantitative description of a teleost exocrine pancreas. Ultrastructural morphometric study of nonstimulated acinar cells. (United States)

    Stipp, A C; Ferri, S; Sesso, A


    The quantitative analysis of exocrine pancreas was fulfilled in teleost fish ( Pimelodus maculatus). The volume fraction occupied by acinar cells, blood vessels and ducts has been assessed by point-counting volumetry in 0.25 micron araldite sections. Measurements of the diameters of the transections of acinar cells nuclei and nucleolus allowed the assessment of the mean nuclear and nucleolar volume according to the method of Bach (1963). With these data, the cytoplasm nuclei and nucleolus volume was calculated in cubic micrometers. Morphometric ultrastructural data was obtained by applying over the electronmicrophotographs (X 21,000) a test system of 84 segments regularly spaced one from another (Weibel 1966). The results obtained was analysed and compared to the mammalian. PMID:6721199

  8. Investigations of the behaviour of fast growing cracks using numerical simulation calculations

    International Nuclear Information System (INIS)

    The behaviour of the SEN sample (flat tensile sample notched on one side) made of Araldite B resin during crack growth was simulated numerically using the finite difference process. In order to obtain the solution for the static initial state of the system after applying the load and before the crack starts, the system set into movement by applying the load was braked until it was in equilibrium. With the equilibrium condition as the initial condition and from the experimentally determined crack growth curves of twelve experiments, a relationship between the speed of fracture and the stress factor was determined with the simulation program, which agreed with the results of the shadow optics evaluation. (orig./HP) With 23 refs., 60 figs

  9. Shear strength of the ASDEX upgrade TF coil insulation: Rupture, fatigue and creep behaviour

    International Nuclear Information System (INIS)

    This report is concerned with the interlaminar shear strength of the insulation system for the 16 toroidal field (TF) coils of ASDEX upgrade. The interlaminar shear properties of the glass-epoxy insulation are primarily determined by the resin system (ARALDIT-F, HT 907, DZ 40) and its curing procedure. The pure resin was therefore tested first in tension. The results were taken into account for setting up the method of curing the TF coils. Shear tests of the complete glass-epopxy system were then conducted with tubular torque specimens providing a nearly homogeneous stress distribution. In particular, the influence of the amount of flexibilizer (5, 10, 15 parts of resin weight = PoW) on the rupture and fatigue strengths was assessed at a temperature T=60 C, as also was the temperature dependence of the creep rate (40 C, 60 C, 80 C). The results obtained are not based on safe statistics. Nevertheless, they show clear trends. (orig.)

  10. Ageing of the LHCb outer tracker

    CERN Document Server

    Blom, M R


    The modules of the LHCb outer tracker have shown to suffer severe gain loss under moderate irradiation. This process is called ageing. Ageing of the modules results from contamination of the gas system by glue, araldite AY 103-1, used in their construction. In this thesis the ageing process will be shown. The schemes known to reduce, reverse, or prevent ageing have been investigated to determine their effect on the detector performance. The addition of O2 to the gas mixture lowers the detector response by an acceptable amount and does not affect the gas transport properties significantly. The ageing rate is decreased after extensive flushing and HV training could eventually repair the irradiation damage. The risks of HV training have been assessed. Furthermore, several gaseous and aquatic additions have been tested for their capability to prevent, or moderate ageing, but none showed significant improvement.

  11. Epoxide insulation for Tokamak coils

    International Nuclear Information System (INIS)

    The construction and testing of 12-tonne toroidal-field electromagnets for the Joint European Torus by Brown Boveri and Cie (Mannheim) are described. The principle of Tokamak confinement of a plasma which acts as the secondary winding of a transformer is explained. The Cu conductors are sanded and coated with epoxide adhesive before being wrapped in 7mm thick woven glass fibre, dried by heating under vacuum, impregnated and encapsulated in 1.2 tonnes of Araldite, which is solidified under pressure of 4 atmospheres and hardened for ten hours at 1500C. The prototype withstood tests involving 25,000 flexure cycles at 1.1 MN and 2 Hz, 2,000 quarter-hour 10kA heating cycles between 840 and 200C, and exposure to 500 million rads. 32 such coils were constructed at the rate of one every three weeks. (M.B.D.)

  12. Mechanical strength of adhesive-bonding

    International Nuclear Information System (INIS)

    In order to meet the prospective application of a GFRP dewar for energy storage system using a large superconducting magnet, the dewar with a complex structure together with a large size are desired to be made. It is difficult to manufacture such a type of the dewars in one united body. These dewars can be manufactured by the adhesive-bonding method. In the present study, the mechanical strength of adhesive-bonding is studied from this point of view. The mechanical strength of the adhesive-bonding has been investigated by the static tensile method and the impact loading method using small test samples. From the static tensile tests, the following results have been obtained. For the sample adhesive-bonded with insertion structure, the mechanical strength of the adhesive-bonding is found to depend on the adhesives used and on the difference of the thermal contraction between the materials which are adhesive-bonded each other. Using a soft adhesive as Araldite 106, the mechanical strength of the adhesive-bonding is small at room temperature, but it remarkably increases at cryogenic temperatures. For a hard adhesive as Araldite 103 and Stycast 2850 FT, it is large at room temperature, and it further increases at cryogenic temperatures. The dewar has to be strong enough not only at cryogenic temperatures but also at room temperature. A soft adhesive is not suitable for constructing the dewar. For the sample adhesive-bonded with screwing structure, the mechanical strength of the adhesive-bonding depends on the shear strength of GFRP itself. The mechanical strength of the adhesive-bonded part increases with the decreasing temperature. Therefore, this screwing method is advantageous for the construction of the dewar. According to the impact loading tests, it is found that the adhesive-bonding of screwing structure is not brittle at cryogenic temperature. This is due to inherent property of GFRP. (J.P.N.)

  13. Application of alcian blue in the electron microscopic study of mouse and human cerebral cortex nerve cells. (United States)

    Castejón, H V; Castejón, O J; Viloria, M E


    Alcian blue is a cationic dye which has been used in the histochemical field for the demonstration of polyanions especially carboxylated and sulphated. The results obtained in neurons when this dye was applied to human and mouse cerebral cortex and studied with the electron microscope are the object of the present report. The CNS of normal adult mice was fixed by vascular perfusion with 2% glutaraldehyde-0.1 M sodium cacodylate-0.1 M sucrose at pH = 6.8 followed by the same fixative with the addition of 0.5% alcian blue. After perfusion, brain cortex was taken out, sectioned into small blocks and immersed in a fresh similar mixture and subsequently in OSO4. Blocks were dehydrated and embedded in araldite. Ultrathin sections were doubly stained with uranyl and lead salts. Human brain cortex taken from patients with cerebral edema was fixed by immersion with 6.5% glutaraldehyde-0.1 M sodium phosphate, pH = 7.4 followed by embedding in warm agar and sectioning in slices of 30 mum thickness which were impregnated by immersion in a mixture of 1% alcian blue-acetate buffer-3% glutaraldehyde at pH = 3.5 for 9 to 15 h at 4 degrees C and subsequently immersed in 1% buffered OSO4-0.1 M sucrose, pH = 7.4 for 2 h at 4 degrees S. Sections were dehydrated and embedded in araldite. Ultrathin sections were doubly stained by uranyl and lead salts. We have denominated the complete procedure in both instances GABOUL technique. The submicroscopic study of both tissues, at nerve cells, revealed the presence of an electron dense homogeneous substance thoroughly dispersed at the hyaloplasmic matrix of perikarya, processes and even synaptic endings. This substance was more evident around free and attached ribosomes, GOLGI apparatus, complex vesicles, dense bodies, microtubules, subsurface cisternae and synaptic vesicles. Canaliculi of endoplasmic reticulum and even the perinuclear cistern also showed a moderate content. It is suggested that this electron dense substance, being

  14. A heavy ion pre-injector for the ICT-ion implanter

    International Nuclear Information System (INIS)

    A cheap and versatile hollow cathode electron bombardment ion source system including its ion extraction-cum-focussing assembly for obtaining intense heavy ion beams of solids and gases is described. The extractor region is designed to include more than 15deg total beam angle of extracted beam for producing focused ion current densities upto 60mA/cm2 to serve as a pre-injector for the ICT(insulated core transformer) type ion implanter. The extraction-cum-focussing lens is a low aberration strong Einzel lens system of all araldite and metal construction with optical elements of proper quality and location to suit low voltage injection and subsequent ion analysis. The injection can be selected anywhere between 2 to 10 keV for singly charged ions with typical extraction currents of 500/μ, using a ring anode and a source aperture of 20 mil. Einzel lens focussing assembly allows continuous adjustment of the beam convergence to about 5deg and the beam size to approximately 5mm in diameter with about 10 KV central electrode potential. Test results of source characteristics for both the accelerating and decelerating model of beam formation have been made. (author)

  15. Properties of ‘Emu’ Feather Fiber Composites

    Directory of Open Access Journals (Sweden)

    V.Chandra Sekhar


    Full Text Available A composite is usually made up of at least two materials out of which one is binding material called matrix and the other is a reinforcement material known as fiber. Many researchers are focusing on natural fiber composites. But, in the present work, composites were prepared with epoxy (Araldite LY-556 resin and „emu‟ bird feathers as fiber. The composites were prepared by varying the weight percentage (P of „emu‟ fiber ranging from 1 to 5 and length (L of feather fibers from 1 to 5 cm. The composite specimens were prepared and cured as per ASTM standards. Studies were carried out on various properties like mechanical properties, Thermal properties and Effect of atmosphere, Soil and certain Chemicals. An attempt is made to model the mechanical properties through response surface methodology (RSM. Analysis of Variance (ANOVA is used to check the validity of the model. The results reveal that the developed models are suitable for prediction of mechanical properties of Epoxy „Emu‟ Feather Fiber Composites.

  16. Chemical Analysis of Emu Feather Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    V.Chandra sekhar


    Full Text Available A composite is usually made up of at least two materials out of which one is binding material called as matrix and other is a reinforcement material known as fiber. For the past ten years research is going on to explore possible composites with natural fiber like plant fibers and animal fibers. The important characteristics of composites are their strength, hardness light in weight. It is also necessary to study about the resistance of the composites for deferent chemicals. In the present work, composites prepared with epoxy (Araldite LY-556 as resin and „emu‟ bird feathers as fiber have been tested for chemical resistance. The composites were prepared by varying fiber loading (P of „emu‟ feathers ranging from 1 to 5 and length (L of feather fibers from 1 to 5 cm. The composites thus prepared were subjected to various chemicals (Acids, Alkalis, solvents etc.. Observations were plotted and studied. The results reveal that there will be weight gain for the composite samples after three days, when treated with Hydrochloric acid, Sodium carbonate, Acetic acid, Sodium hydroxide, Nitric acid and Ammonium hydroxide. Weight loss was observed for all the samples including pure epoxy when treated with Benzene, Carbon tetra chloride and Toluene.

  17. Post-embedding tem signal-to-noise ratio of S-100 (United States)

    Fermin, C. D.; Lee, D. H.; Martin, D.


    We assessed the reactivity of purified S-100 antiserum in immuno-electron microscopy by counting the number of gold particles per microns 2 over inner ear tissues embedded in different media. Sections containing predominantly Schwann's cell cytoplasm and nucleus, afferent fiber axoplasm and myelin sheath of chick cochleae were reacted with anti-S-100 IgG, an antibody to a calcium binding protein of neuronal tissues, then labeled with anti-IgG-gold conjugate. This investigation was conducted because previously published procedures, unmodified, did not yield acceptable results. Preparation of all specimens was identical. Only the medium (PolyBed 812, Araldite or Spurr epoxies; and LR White, LR Gold or Lowicryl plastics) was changed. The medium was made the changing variable because antigens available in post-embedding immuno-electron microscopy are decreased by heat, either used and/or released during polymerization of the embedding medium. The results indicate that: (a) none of the embedding media above provided optimal signal-to-noise ratio for all parts of the nerve stained in the same section; (b) aggregation of gold particles over cells was highest in embedding media with high background labeling over areas devoid of tissue (noise); (c) aggregation occurred randomly throughout both cellular and acellular regions; and (d) particles aggregated less and were distributed more evenly in tissues from media yielding good ultrastructural integrity.

  18. Experimental investigation on fracture of layered plates (United States)

    Agnihotri, Servesh; Parameswaran, Venkitanarayanan


    Layered structures, used in many applications such as windshields, thermal protection systems, heavy armor etc., are comprised of layers having different elastic and fracture properties. Present study focuses on understanding the behavior of cracks in a layered plate oriented in such a way that there are property jumps across the crack front. Two layer plates were fabricated by joining Polymethylmethacrylate (PMMA) and epoxy sheets using an epoxy based adhesive (Araldite). Single edge notched specimens were subjected to mixed mode loading using the asymmetric four point bending configuration. The results of the study indicated that the failure in two layer plates is progressive in nature. Crack extension starts in the most vulnerable layer (epoxy) first and the crack grows in a sequence of jumps and arrests in this layer. Once this crack reaches a particular length the crack in the second layer starts extending resulting in final failure of the plate. Similar sequence of events was observed in the case of dynamically loaded samples. The predictions of the load at which epoxy crack starts growing and the angle at which the crack grows using the maximum tensile stress criteria were in reasonable agreement with the experimentally observed values.

  19. New approaches to the full-field analysis of photoelastic stress patterns (United States)

    Buckberry, C.; Towers, D.


    This paper presents two new methods that provide a complete solution for the automatic fringe analysis of photoelastic data. Previous solutions have not yet provided a complete full-field analysis of both fringe sets (isochromatic and isoclinic) over a multiple number of fringes with an automatic measurement of absolute magnitude. This paper reviews previous approaches and discusses the options along which this work has been directed. Specifically, two new algorithms are presented. Firstly, the combination of phase maps at three wavelengths in order to remove the isochromatic ambiguity at every π turning point, that would occur in a single phase map. Additionally, this algorithm allows the automatic measurement of absolute magnitude, providing the neutral axis is within the field of view. Secondly, a new method is proposed that removes the areas of 2π ambiguity in an isoclinic phase map by cross-correlating regions of low modulation at two different wavelengths. The algorithms are demonstrated by applying them to the analysis of an engine connecting rod. The rod was manufactured as a full-scale three-dimensional model in araldite (Ciba-Geigy CT200), from which a central slice was taken after having been stress frozen.

  20. Preparation techniques alter the mineral and organic fractions of fish otoliths: insights using Raman micro-spectrometry. (United States)

    Jolivet, Aurélie; Fablet, Ronan; Bardeau, Jean-François; de Pontual, Hélène


    The high spatial resolution analysis of the mineral and organic composition of otoliths using Raman micro-spectrometry involves rigorous protocols for sample preparation previously established for microchemistry and trace elements analyses. These protocols often include otolith embedding in chemically neutral resin (i.e., resins which do not contain, in detectable concentration, elements usually sought in the otoliths). Such embedding may however induce organic contamination. In this paper, Raman micro-spectrometry reveals the presence of organic contamination onto the surface obtained from the use of epoxy resin, specifically Araldite. This contamination level varies depending on otolith structures. Core and checks, known as structural discontinuities, exhibit the most important level of contaminations. Our results suggest that otolith embedding with resin affects the organic matrix of the otolith, probably through an infiltration of the resin in the crystalline structure. The interpretation of chemical otolith signatures, especially Raman otolith signatures, and stable isotope analyses should then be revised in light of these results. In this respect, we propose a method for the correction of Raman otolith signatures for contamination effects. PMID:23508582


    Directory of Open Access Journals (Sweden)



    Full Text Available The aim of this investigation is to comprehensively understand the polymeric composite behavior under direct fire sources. The synergistic effects of hybrid flame retardant material on inhabiting the pyrolysis of hybrid reinforced fibers, woven roving (0°- 45° carbon and kevlar (50/50 wt/wt, and an araldite resin composites were studied. The composites were synthesised and coated primarily by zinc borate (2ZnO.3B2O3.3.5H2O and modified by antimony trioxide (Sb2O3 with different amounts (10-30 wt% of flame retardant materials. In the experiments, the composite samples were exposed to a direct flame source generated by oxyacetylene flame (~3000ºC at variable exposure distances of 10-20 mm. The synergic flame retardants role of antimony trioxide and zinc borate on the composite surface noticeably improves the flame resistance of the composite which is attributed to forming a protective mass and heat barrier on the composite surface and increasing the melt viscosity.

  2. Residual stress relaxation measurements across interfaces at macro-and micro-scales using slitting and DIC

    International Nuclear Information System (INIS)

    In this paper digital image correlation is used to measure relaxation of residual stresses across an interface. On the macro scale the method is applied to a tri-layer bonded aluminium sample, where the middle layer is in tension and the top and the bottom layers are in compression. High contrast speckle pattern was sprayed onto the surface. The relaxation was done with the slitting saw. Three dimensional image correlation was used. On the micro scale the technique was applied to a heat treated large grain brass loaded in tension. Mechanical and electro polishing was used for surface preparation. A focused ion beam was used for slitting across a grain boundary and for imaging. Grain orientation was measured using electron back-scattering diffraction. Two dimensional image correlation was employed. In all macro- and micro-scale experiments the range of measured relaxation was sub-pixel, almost at the limit of the resolution of the image correlation algorithms. In the macro-scale experiments, the limiting factor was low residual stress, due to low shear strength of the Araldite glue used for bonding. Finite element simulation of the relaxation agreed only qualitatively with the experimental results at both size scales. The methodology is intended for use with inverse methods, i.e. the measured relaxation is applied as the boundary conditions to an appropriate FE model which produces stresses equal to the relaxed residual stresses, but with opposite sign. The main conclusion is that the digital image correlation method could be used to measure relaxation caused by slitting in heterogeneous materials and structures at both macro- and micro-scales. However, the repeatability of the techniques needs to be improved before residual stresses can be determined confidently. Acknowledgments The authors gratefully acknowledge Airbus UK for provision of materials. They thank Dr Richard Burguete, Airbus UK, and Prof Peter Flewitt, Department of Physics, University of Bristol, for

  3. On the validity of Ksub(Id)-measurements in instrumented impact tests

    International Nuclear Information System (INIS)

    The influence of inertia effects in determining the dynamic fracture toughness Ksub(Id) by instrumented impact testing is investigated. Model experiments in the brittle fracture regime are carried out with precracked bend specimens machined from the epoxy resin Araldite B. As is usual in these tests, the loads at the tup of the impinging striker are recorded as a function of time during the impact process. For reference purposes, the dynamic fracture toughness value Ksub(Id)sup(m1) is derived from the measured maximum load utilizing static stress intensity factor formulas. In addition to this conventional procedure, the actual stress intensity factors are measured directly at the tip of the crack by means of the shadow optical method of caustics applied in combination with high speed photography. The critical value of these optically measured stress intensity factors (for onset of crack propagation), Ksub(Id)sup(opt), is the true dynamic fracture toughness. In the experiments, the specimen size and the impact velocity were varied. In accordance with expectations, it is found that the hammer load signal is not correlated with the actual crack tip stress intensity factor values by a simple proportionality. The conventionally determined Ksub(Id)sup(m1)-value overestimates the true dynamic fracture toughness Ksub(Id)sup(opt). This overestimation becomes larger for larger specimen sizes and larger impact velocities. The results demonstrate the dominating influence inertia effects can have on hammer load measurements and emphasize the importance of eliminating these effects in order to determine non-erroneous dynamic fracture toughness values. (orig.)

  4. Polymer Magnetic Composite Core Based Microcoils and Microtransformers for Very High Frequency Power Applications

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    Saravana Guru Mariappan


    Full Text Available We present a rapid prototyping and a cost effective fabrication process on batch fabricated wafer-level micro inductive components with polymer magnetic composite (PMC cores. The new PMC cores provide a possibility to bridge the gap between the non-magnetic and magnetic core inductive devices in terms of both the operating frequency and electrical performance. An optimized fabrication process of molding, casting, and demolding which uses teflon for the molding tool is presented. High permeability NiFeZn powder was mixed with Araldite epoxy to form high resistive PMC cores. Cylindrical PMC cores having a footprint of 0.79 mm 2 were fabricated with varying percentage of the magnetic powder on FR4 substrates. The core influence on the electrical performance of the inductive elements is discussed. Inductor chips having a solenoidal coil as well as transformer chips with primary and secondary coils wound around each other have been fabricated and evaluated. A core with 65% powder equipped with a solenoid made out of 25 µm thick insulated Au wire having 30 turns, yielded a constant inductance value of 2 µH up to the frequency of 50 MHz and a peak quality factor of 13. A 1:1 transformer with similar PMC core and solenoidal coils having 10 turns yielded a maximum efficiency of 84% and a coupling factor of 96%. In order to protect the solenoids and to increase the mechanical robustness and handling of the chips, a novel process was developed to encapsulate the components with an epoxy based magnetic composite. The effect on the electrical performance through the magnetic composite encapsulation is reported as well.

  5. Gill Morphology and Oxygen Diffusion Distance in Juvenile Striped Killifish, Fundulus majalis (United States)

    McEnroe, M.; Rivera, L.; La Fortune, B.; Miller, A.


    Striped killifish (Fundulus majalis) are an important estuarine forage fish. Larvae and juveniles utilize shallow marsh pools which become warm (>30 C) and hypoxic (DO environment we studied gill morphology. Gill surface area (GSA) and oxygen diffusion distance are important parameters for oxygen uptake, as expressed by Fick's Equation for diffusion. To measure these parameters fish (N=20, 20-50 mm TL) were collected from marsh pools and adjacent Long Island Sound in late summer, weighed, and measured. The gills were fixed in Karnovsky’s solution. For scanning electron microscopy (SEM) they were rinsed, dehydrated in a graded ETOH series, and critically point dried, sputter-coated and were observed with ISR-SR-50 SEM. Gill morphology (number of filaments, filament length, lamellar density, and lamellar size) were quantified using SEM. Total gill surface area (GSA) was calculated using the method of Hughes (1984); GSA = L* n* bl where L = sum of filament lengths, n = number of lamellae/mm, and bl = bilateral lamellar surface area. To measure oxygen diffusion distance from water to blood, samples were embedded in Araldite 502/Embed 812 TM plastic medium for transmission electron microscopy (TEM). Stained (uranyl acetate and calcinated lead citrate) thin sections were examined using a FEI/Philips Morgagni 268 transmission electron microscope (TEM). Gill lamellar diffusion distance was measured using the technique of Matey et al., 2008 and found to be low (1.0 µm ± 0.4; mean ± SD; N= 17). Gill structure and oxygen diffusion distance will be compared to other fishes from normoxic and hypoxic environments.

  6. CA.C.I.U.S.: Ultrasonic C imaging camera. Contribution to its study and its realization

    International Nuclear Information System (INIS)

    CA.C.I.U.S. is a dynamic imaging three-dimensional echographic camera. This device provides automatic C images which are frontal slices, orthogonal to the ultrasonic propagation. The detector has a cylindrical shape, its focal length of 250 mm and its size is 220 x 143 mm. The useful field is less large (170 x 143 mm) regarding the impossibility to use entirely the 73 elements electronic pattern on the edges. The emitting array is done in two parts. These two parts. The receiver is an electronically focused mono-dimensional array made of 147 elements (0,8 x 5 mm2) spaced 0,7 mm apart, placed between the emitting arrays. These two arrays contain 22 strips of ten bent transducers (10 x 13,7 mm2). The receiver elements are protected form the water of the tank by a loaded araldite layer of λ/4 thickness which allows a better uniformity response with the reception angle. The array elements are matched to 2.2 MHz, the basking is made of a multilayer plastic material (CELORON). This device allows a geometric focalization of the emission. The thickness of each slice C is 2 ± 0,5 cm, depending on its place in the frontal place (better in the center) and on the weighing factors adjusted at the back of the emitting array. The spatial resolution is 1.5 mm (F. W.H.M.) in the two axis orthogonal to the ultrasonic propagation. Several receivers were made. The electronic pattern was optimized by computer study, its results showed an improving of the image definition. Logarithmic amplifiers were used behind each element to allow simultaneous analysis of small echoes coming from the tissue itself and big boundary echoes. The array was placed in a tank filled with water closed by a double membrane. The visualization was obtained in a grey scale dynamic memory. Several emission reception synchronizations were studied. The slowest mode (1 image by second) gave the best signal on noise ratio. CA.C.I.U.S. demonstrates the reality of the slow dynamic C echography and the necessity of a

  7. The use of embedded sensors for the monitoring of adhesive joints in marine environments (United States)

    McGovern, Scott T.; Spinks, Geoffrey M.; Wallace, Gordon G.


    A copolymer incorporating polyaniline was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised in the presence of poly (butyl acrylate / vinyl acetate) and a copolymer containing polyaniline emeraldine salt was obtained. The sensing medium was then developed by redissolving 1-2 w/w% of the resulting polymer residue in dichloromethane to produce a processable polymer blend solution. Some of this polymer residue was also de-doped in a solution of ammonia, and then washed with distilled water until the waste water had a neutral pH. This residue was then redissolved at 1-2 w/w% in dichloromethane to produce a second processable polymer blend this time containing polyaniline emeraldine base. The final sensor design utilised 125μm polyester insulated platinum wire as conducting electrodes that were dip coated in the emeraldine salt copolymer solution and allowed to dry in a desiccator. The sensor was then dip-coated in a protective barrier layer of the emeraldine base copolymer to prevent over-oxidation and/or de-protonation of the emeraldine salt sensing medium under this coating. The sensors had an overall final thickness of less than 150μm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. Sensors were monitored for 2-probe resistance changes when in contact with water. Calibration curves for each sensor were produced to convert the resistance reading to mass uptake of water. Individual sensors were embedded within Aluminium 5083 / Araldite 2015 adhesive joints to monitor mass uptake of water when exposed to marine environments. Correlations between mass uptake of water and joint strength were made. There are various advantages of such a sensor design. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. The ease of

  8. A review of the use of Streptozotocin (STZ in the induction of diabetes in rats and subsequent ocular tissue changes

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    H. L. Sithole


    Full Text Available Streptozotocin is widely used in medical research for treating certain cancers of the Islets of Langerhans and to produce an animal model for type 1 diabetes. A study has revealed that when compared to the control group of rats, those injected with STZ exhibited reduced plasma insulin and elevated blood glucose (p < 0.05 in all cases. The study also found that diabetic rats weighed significantly less than control animals (p < 0.05. In relation to ocular tissues, lacrimal glands from diabetic rats were also found to weigh significantly less  (p < 0.05 than those from the control group. However, no significant changes in the weights of lens, cornea, sclera and retina were observed between diabeticand control animals. Several other studies found that STZ-induced diabetes can be treated by plant extracts which control the blood sugar level as well as improving the lipid profile and ocular complications such as retinopathy. Experiments are usuallyperformed on male or female rats of a specific body weight, usually between 250 and 300 g. Diabetes is induced in rats by intraperitonial injections of streptozotocin (60 mg/ kg in citrate buffer, pH 6.3.Animals that exhibit glucosuria after 24 hours, test-ed by urine test strips are considered diabetic. Plant extracts (6 mg/100g body weight are orally administered into the stomach of STZ-diabetic rats every third day at a certain consistent time by means of bulbed steel needle for at least a four week period. This is done to determine the efficacy and potency of the plant extracts on diabetes. Histological and transmission electron microscope (TEM techniques are used to study the changes in the ocular tissues. The dissected ocular tissues should be dehydrated in graded ethyl alcohol series and embedded in Araldite CY212. Ultra thin sections should be contrasted with uranyl acetate and lead citrate for examination by TEM. Streptozotocin induces diabetes in laboratory animal models for scientific studies and

  9. Síndrome Respiratorio Agudo Grave: El laboratorio de salud pública frente a una emergencia global Severe acute respiratory syndrome: The public health laboratory in a global emergency

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    Elsa G. Baumeister


    Full Text Available A fines del año 2002 se inicia un brote de neumonía atípica en el Sudeste asiático el cual se extiende posteriormente a otros continentes. El nuevo síndrome respiratorio agudo grave (SARS era producido por un coronavirus novedoso. Debido a la gravedad de la situación y al riesgo de introducción de esta patología en Argentina, se implementaron técnicas de diagnóstico clásicas como la microscopía electrónica, y moleculares como una reacción de retrotranscripción seguida de una reacción en cadena de la polimerasa (RT-PCR. La inclusión en araldita de células infectadas con un coronavirus bovino permitió visualizar más fácilmente las partículas virales, pero requirió más tiempo en comparación con la coloración negativa de partículas libres de cultivos virales. La RT-PCR implementada fue capaz de detectar ARN de cepas de casos de Hong Kong y de Alemania.By the end of year 2002 there was an outbreak of atypical pneumonia in Southeast Asia which soon spread to other continents. This new severe acute respiratory syndrome (SARS was produced by a novel coronavirus. Due to the severity of the situation and risk of introduction of this pathology in our country, the need to arrange specific laboratory diagnostic tests arose. Classic techniques, such as the electron microscopy and molecular biology test such as retrotranscription followed by the polymerase chain reaction (RT-PCR were implemented. The araldit included cells infected with bovine coronavirus which allowed the viral particles to be visualized easily but it took more time in comparison with the negative staining of free particles from viral cultures. RT-PCR was able to detect RNA of isolated viruses from cases in Hong Kong and Germany.

  10. Hydroxyl and calcium ions diffusion from endodontic materials through roots of primary teeth - in vitro study Avaliação in vitro da difusão de íons Ca+2 e OH- de materiais endodônticos em dentes decíduos

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    Ana Cristina Gerent Petry Nunes


    Full Text Available The purpose of this research was to evaluate the diffusion of calcium (Ca+2 and hydroxyl (OH- ions from materials with a calcium hydroxide base - Ca(OH2 through the intact roots of deciduous teeth. This diffusion of ions is important for periapical healing. Forty-six deciduous teeth were selected and instrumented to their working length with #40 files. The teeth were washed during cleaning and shaping with a 1% sodium hypochlorite (NaOCl solution. The canals were dried with paper points. The teeth were divided into 4 groups based on the sealer type, with 10 specimens in each group. A fifth group of 6 teeth without sealer constituted the control group. The materials used as sealers were: Ca(OH2 paste associated to propylene glycol (CaPE thickened at the proportion of 2:1 w/v; UFSC (Federal University of Santa Catarina paste - a mixture of 0.3g of zinc oxide with 0.3g of Ca(OH2 with 0.2ml of olive oil 1:1 w/w; Vitapex® and Sealapex®. The coronal access was sealed with a glass ionomer after the root had been filled with each sealer. A one-third apical surface and foramen was hard-pressed with Araldite®. The teeth were stored individually in flasks containing saline solution at 37ºC and 100% humidity. The OH- and Ca+2 ions diffusion levels were determined using a pH meter and an atomic absorption spectrometer. Data were collected at 48 hours and at intervals of 7, 30, 45 and 60 days. Statistical analysis was performed using ANOVA to compare groups. In the pH evaluation, the CaPE group presented the largest OH- ions diffusion, which peaked at sixty days (p=0.0309, when compared to the other groups (pO objetivo desta pesquisa foi avaliar a difusão de íons Ca+2 e OH- de materiais endodônticos a base hidróxido de cálcio - Ca(OH2, através da raiz intacta de dentes decíduos. 46 dentes decíduos foram selecionados e instrumentados em seu comprimento de trabalho até a lima # 40, e irrigados durante o preparo com solução de hipoclorito de s

  11. An overall view on corrosion and bio-fouling problems in sea water cooling systems at MAPS

    International Nuclear Information System (INIS)

    MAPS is a twin unit-220 MWe Pressurised Heavy Water Reactor (PHWR) nuclear power station using seawater as cooling medium in main steam condensers and in the Process Sea Water Heat Exchangers (PSWHXs). The seawater system consists of intake structure, submarine tunnel, fore-bay and pump house, travelling water screens, associated pumps and piping, heat-exchangers and out-fall structure. The horseshoe type submarine tunnel of length 468 metres and diameter 3.85 metres carrying ∼ 1.3 lakh m3/hr seawater from the intake structure to the pump house is lined with special concrete of 225 mm thickness. The major portion of piping carrying seawater is made of concrete and coal-tar based epoxy coated mild steel. Some portions of the mild steel pipes were gunnited and coated with araldite to minimise corrosion and fouling. The tubes of the condensers and the PSWHXs are of aluminium brass and the tube sheets are of aluminium bronze. The water boxes are rubber-lined with 3 mm thick neoprene and 2% magnesium iron sacrificial anodes are also provided in the water boxes to minimise corrosion. Plastic inserts are installed at the inlets of the tubes to prevent damage due to impingement attack and erosion. Ferrous sulphate dosing is being carried out to minimize the corrosion of aluminium brass tubes. Biofouling control (both Micro/Macro) is effected by gaseous chlorination at the rate of 30 - 40 Kg/hr for ∼ 20 hrs daily with residuals of 0.20 ppm. Further, booster dose (Liquid chlorine injection through evaporator) is given twice a week with a residual of ∼ 0.50 ppm and the dose required for this treatment is met by using evaporators. The major marine species identified in the intake and forebay were large barnacles and green mussels whereas the species identified in the PSWHXs were small size Barnacles (B. Reticulatus, 3 - 4 mm in size) and Mussels ( M.Striatulus, 5 - 8 mm in size). The main condensers are being cleaned during planned outages whereas it is not possible to

  12. Degradation processes and consolidation of Late Jurassic sandstone dinosaur tracks in museum environment (Museum of Lourinhã, Portugal) (United States)

    Leal, Sofia; mateus, Octavio; Tomas, Carla; Dionisio, Amelia


    The current study aims to conciliate conservation and restoration museology diagnosis with paleontological and geological curational needs and has, as subject of study, dinosaur footprints (vertebrates fossils). The footprints have been being exposed since 2004 in the paleontology hall of the Museum of Lourinhã, Portugal, and are part of a important paleontological collection of Late Jurassic vertebrate fossils from Lourinhã Formation. Presently, it is considered a unique heritage in danger of disappearing due to high decay level of disaggregation of its geological structure. The dinosaur footprints, (ML557) found, more precisely, on a coastline cliff in Lourinhã, Porto das Barcas, Lagido do Forno (coordinate 39° 14. 178'N, 9° 20. 397'W), Jurassic period, on the 5th of June 2001, by Jesper Milàn. This cliff of high slope presents sedimentary stratigraphic characteristics of a sandstone/siltstone of gray and red colors, by the '' Munsell scale and Color Chart''. Geological the tracks are Late Jurassic in age, and colected in the Lourinhã Formation, Praia Azul Member, of the Lusitanian Basin. There are three natural infills tridactyl tracks, possibly ascribed to ornithopod, a bipedal herbivore, resultant of a left foot movement, right and left. Footprints have 300-400mm of wide and 330-360mm of height with round fingers, which are elongated due to some degradation/erosion. In 2001, the footprints were collected from the field, cleaned, consolidated and glued in the laboratory of the Museum of Lourinhã before being exhibited in a museum display. Stone matrix was removed and a consolidation product applied, probably a polyvinyl acetate, of the brand Plexigum. The footprint with broken central digit was glued with an epoxy resin, Araldite. Both applied products were confirmed by analysis of µ-FTIR (Fourier Transform Infrared Spectroscopy) and both presented colour change and detachment surface problems. After collecting and storing, in 2004, footprints were