The industrial radiation processing using low energy electron beam (EB) accelerators lower than 300 keV offers high speed, safe technologies for the chemical conversion of thin layer coatings. Because of the nonselective mode of initiating chain reaction polymerization involving free radicals in synthetic coating layers and suitable substrates, the EB curing of the coatings on woods and papers has particular advantage. Hungary decided to start an up-to-date EB line to process cement-bound (CB) wood chipboards with pigmented acrylic coatings. The CB wood chipboards contain more than 60 % of portland cement and up to 40 % of wood particles. They are produced as large boads of 6 - 16 mm thickness. In their fireproof character and other aspects, they are similar to asbestos-cement boards without containing carcinagenic asbestos, and are stable against moisture and atmospheric ...
Hard Nano-Strutural Coatings Resistant to the Extreme Conditions of Chemical, Abrasive and High Energy Media for Thermonuclear Power, Oil and Gas and Chemical Industries
The effect of a substrate on the results of measuring tantalum coating thickness in two-layer compositions according to gamma radiation scattered by the substrate is studied. It is shown that by means of an albedo-radiometer realizing the physical model absorber-scatterer one can determine the thickness (application uniformity) of tantalum coatings up to 150-300 #mu#m depending on the substrate material (plexiglas, aluminium, iron, copper). In case of testing coatings on substrates of alloys and high-alloy steels in order to ensure high accuracy of measrurement it is expedient with the above albedo-radiometer to determine the value of the backscattered radiation flux for the substrate before coating application.
One requirement of a thermophotovoltaic (TPV) radiator is to efficiently emit photons at high temperatures to TPV cells for conversion to electric power. Because many candidate radiator materials with adequate structural properties display low emissivity, coatings or other surface modifications are required for enhancement of emissivity. Six plasma sprayed coatings and one textured surface demonstrated adequate thermal stability and emittance values of 0.8 or greater. Promising attributes of modified surfaces are identified.
drical Enclosures Using a Numerical Ray Tracing Technique. NASA. TM-I02527, 1990 . Buckley, H.: Radiation from the Interior of a Reflecting Cylinder. Philos. ...
Electron beam (EB) processing involves using electrons to initiate polymerization or cross-linking reactions in suitable substrates, thereby enhancing specific physical and chemical properties. A relatively new use of EB processing is now emerging: the production of fibre-reinforced composites. EB curing at ambient temperature has the potential to reduce the residual stresses in an advanced composite, a result of expansion during thermal curing, and to significantly increase the overall cure speed and process throughput. Wood fibres are used as a filler material for various thermoplastics such as polypropylene. EB treatment, combined with selected EB-curable coupling agents, significantly increases the adhesion between the wood fibres and the thermoplastic polymer, resulting in improved material properties. Work to develop both products and processes for the EB curing of fibre-reinforced composites is currently underway at AECL Research. This paper briefly updates ...
An improved coating for Advanced Gas Cooled Nuclear Reactor austenitic stainless steel fuel cans is described which, tests have shown, inhibits the deposition of carbon on the cans in carbon-containing ionising radiation environments. The coating comprises a refractory oxide which has been prepared by a vapour phase condensation method, in combination with a noble metal. (U.K.).
An industrial EB processing line is started to produce cement-bound /CB/ chipboard with radiation cured acrylic coating. The basic features of this line are presented here. The main technological parameters of coating such as: effect of oligomer- and monomer reactivity, monomer functionality, dose-rate and inerting atmosphere on the progress of curing have been discussed. The EB processed CB board is an advanced composite material for the modern lightweight architecture.
With advances in treatment, colorectal cancer is being transformed from a deadly disease to an illness that is increasingly curable. With this transformation has come increased interest in the...Full Text Available
Tumour hypoxia represents a significant challenge to the curability of human tumours leading to treatment resistance and enhanced tumour progression. Tumour hypoxia can be detected by non-invasive and...Full Text Available
Tumour hypoxia represents a significant challenge to the curability of human tumours leading to treatment resistance and enhanced tumour progression. Tumour hypoxia can be detected by non-invasive and...Full Text Available
The determination of residual stress (RS) in case-hardened steel gear truck synchronisers coated with thermal sprayed molybdenum was carried out using neutron and synchrotron X-ray diffraction. Two samples with different coating thicknesses (about 120 ?m and 1.4 mm) and different steel substrates (16MnCr5 and SAE4140, respectively) were investigated. Microanalysis revealed substantial porosity in both samples and some debonding was observed between the thin coating and the substrate. The bulk hardness of the SAE 4140 proved to be much higher than the 16MnCr5 and the surface case-hardening increased it by a further 20%. The full three-dimensional stress depth-profile was determined by neutron diffraction (ND) in both the coatings and the substrates, while synchrotron radiation allowed a dep...
The principle is described of a method using low-activity emitters as the primary radiation source for analysis. The selection of the radiation source and the detection methods including the assessment of the applicability of various radiation detectors are discussed. The benefits and the constraints of the method are considered. Practical examples are presented showing the application possibilities of the method for testing the thickness of bearing layers, piston ring coats, lead layers, etc. The possibility is shown of applying the rapid test for the composition of tungsten and chromium alloyed metal materials in testing complex systems. (J.K.).
This Test Plan outlines the testing to be done on the Special Protective Coating (SPC) Polyurea which includes: Tank Waste Compatibility, Decontamination Factor Testing, and Adhesion Strength Testing after a sample has been exposed to Radiation.
In this work a comprehensive metallophysical study was carried out for two aluminosilicide slip coatings of the systems Al-Si and Al-Nb-Si and an electron-beam Co-Cr-Al-Y coating on alloy EP-539 (17...19% Cr, 4...6% Co, 2.5...4% W, 4.5...6.5% Mo, 2...3% Ti, 3...4% Al, 1.4...2% Nb, balance Ni) after high-temperature testing. The protective properties of the coatings were evaluated from the results of laboratory tests for heat resistance at 1000/sup 0/C in the combustion products of diesel fuel with added sulfur at 970, 1000, and 1060/sup 0/C for 100 h and after full-scale tests for 150, 250, 400, and 700 h. Metallographic, hardness, x-ray, and micro x-ray studies of the coating were carried out. Layer-by-layer phase composition and the lattice spacing of the main phases were determined. X-ray analysis was carried out in an a DRON-1 diffractometer in copper K/sub ...
Multilayer mirror coatings which reflect extreme ultraviolet (EUV) radiation are a key enabling technology for EUV lithography. Mo/Si multilayers with reflectances of 67.5% at 13.4 nm are now routinely achieved and reflectances of 70 2% at 11.4 nm were obtained with MO/Be multilayers. High reflectance is achieved with careful control of substrate quality, layer thicknesses, multilayer materials, interface quality, and surface termination. Reflectance and film stress were found to be stable relative to the requirements for application to EUV lithography. The run-to-run reproducibility of the reflectance peak position was characterized to be better than 0.2%, providing the required wavelength matching among the seven multilayer-coated mirrors used in the present lithography system design. Uniformity of coating was improved to better than 0.5% across 150 mm diameter substrates. These improvements in EUV ...
A device for detecting neutrons includes a semi-insulated bulk semiconductor substrate having opposed polished surfaces. A blocking Schottky contact comprised of a series of metals such as Ti, Pt, Au, Ge, Pd, and Ni is formed on a first polished surface of the semiconductor substrate, while a low resistivity ("ohmic") contact comprised of metals such as Au, Ge, and Ni is formed on a second, opposed polished surface of the substrate. In one embodiment, n-type low resistivity pinout contacts comprised of an Au/Ge based eutectic alloy or multi-layered Pd/Ge/Ti/Au are also formed on the opposed polished surfaces and in contact with the Schottky and ohmic contacts. Disposed on the Schottky contact is a neutron reactive film, or coating, for detecting neutrons. The coating is comprised of a hydrogen rich polymer, such as a polyolefin or paraffin; lithium or lithium fluoride; or a heavy metal fissionable material. By varying the ...
Full text: Institute for Nuclear Research, Pitesti-Mioveni, Romania in direct cooperation with the National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest studied and prepared for coating more than 1000 tiles made of Inconel with 7-9 #mu#m of beryllium for nuclear fusion applications at JET, Culham, UK. The principles of manufacturing processes using thermal evaporation and plasma ignited in pure metal vapors as well as by Thermionic Vacuum Arc (TVA) method and the properties of the Ni and Be coatings are presented. The prepared beryllium layers were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. (authors)
Metal oxide semiconductor (MOS) integrated circuits, with the benefits of low power consumption, represent the state of the art technology for implantable medical devices. Three significant sources of radiation are classified as having the ability to damage or alter the behavior of implantable electronics; Secondary neutron cosmic radiation, alpha particle radiation from the device packaging and therapeutic doses(up to 70 G{gamma}) of high energy radiation used in radiation oncology. The effects of alpha particle radiation from the packaging may be eliminated by the use of polyimide or silicone rubber die coatings. The relatively low incidence of therapeutic radiation incident on an implantable device and the use of die coating leaves cosmic radiation induced secondary neutron ...
Pyrheliometric methods are described (particularly methods for measuring the solar constant), and theoretical and experimental studies in this field are surveyed and systematized. Particular attention is given to the analysis of instruments intended for pyrheliometers used as standards, reference instruments, and solar-constant meters is examined, and consideration is given to methods for determining the thermal-radiation properties of absorbing coatings and methods for calculating the absorption coefficients of cavity receivers.
The neutron detector is cased in a metal envelop and has one detector with a very sensitive fission chamber and a second detector with a fission chamber less sensitive that the first one and a boron coated ionisation chamber for reducing gamma radiation detection.
With conventional heating process, ultraviolet (UV) illumination, and microwave irradiation, we have successfully synthesized UV curable encapsulating adhesives with excellent gas barrier capabilities, good adhesive strength, moderate hardness, and high refractive indices. The experimental results manifest that the physical properties of lab-made encapsulating adhesives are highly dependent on their chemical structures and synthetic procedure. We also discover that the encapsulating adhesive prepared by microwave irradiation (i.e. encapsulating adhesive VI-MW) exhibits better adhesive strength and higher gas resistance than those prepared by conventional heating process and UV illumination. Furthermore, encapsulating adhesive VI-MW has also been applied for the package of organic light emi...
There are three main types of radiation-processed composite material derived from plastics and fibrous natural polymers. The first are the monomer-impregnated, radiation-treated wood-plastic composites (WPC). They became a commercial success in the early 1970s. More recently, work has focused on improving the WPCs by creating in them interpenetrating network (IPN) systems by the use of appropriate multifunctional oligomers and monomers. The main kinetic features of radiation-initiated chain polymerization remain applicable even in impregnated wood. The second type are the plastics filled or reinforced with dispersed wood fiber or other cellulosics (WFRP). In their case, radiation processing offers a new opportunity to apply radiation-reactive adhesion promoters between wood or cellulosic fibers and the thermoplastic matrices. The third type are the laminar composites made by ...
The information reported is for the period October I to December 31, 1993. During this quarter, activities were undertaken in Task 2. Oxygen concentrations were measured in the post-flame region of the entrained flow reactor. The sampling probe was used for the hot gas tests to sample the gas stream. Samples were injected into a gas chromatograph to determine the oxygen concentration. Results agreed with thermoequilibrium calculations that yield equilibrium compositions based on the stoichiometry of the feed gases. The axial temperature distribution along the reactor centerline was measured using a silica-coated platinum-rhodium thermocouple. Two coating techniques were tested and it was found that flame-plating silica to the thermocouple wires produced a thinner coating than a ceramic adhesive technique and therefore a smaller radiation correction. Other activities this quarter included the fabrication ...
Full text of publication follows: As SiCf/SiC composites are very low activation materials, their use as structural material for the reactor blanket and first wall components appears essential to demonstrate the potential of D-T fusion power reactor. Positive features of SiCf/SiC are their high performances at elevated operating temperature and the ability to produce a specific component. Critical issues of SiCf/SiC are the mechanical properties, radiation stability and, with regard to technological issues, their hermeticity and joining processes. Improvement of joining processes for SiC/SiC components is also needed. Recently, several blanket designs have been studied: the TAURO blanket concept in the European Union, the ARIESAT concept in the US and the DREAM concept in Japan. In those reactors, hermetic SiCf/SiC or self-sealing coatings are mandatory. The basic idea of self sealing concept is to manufacture a coating ...
Two types of thermal control materials based on polyimide film UPILEX-R are designed. One of thermal control material R/Al is coated with Al on the back surface. The other of thermal control material TCC/R/Al is coated with transparent conductive coating on the font surface and is coated with Al on the balk surface. The solar absorptance is measured spectroscopically with an integrating sphere in the wavelength region of 0.26 - 2.50 {mu}m and the total hemispherical emittance is measured calorimetrically in the temperature range of -100-+100{degree}C for the present thermal control materials. To evaluate the space degradation of optical properties (refractive index, extinction coefficient, absorption coefficient) on UPILEX-R film and solar absorptance on thermal control materials, space environment simulation tests are performed on the ground with independent radiation and combined ...
Various remedial measures have been tried to lower radon levels in buildings in Uranium City. The methods used are source material removal, passive ventilation of crawl spaces, sub-floor ventilation, complete epoxy coating of the entire basement, sealants for floor-wall joints and cracks in basements, electrostatic precipitators, mechanical ventilation, and sealing and grouting concrete block plenums in basement walls. The type and condition of structures encountered in Uranium City as well as the relative isolation of the town indicate that mechanical ventilation is the most long-term cost-effective method.
In this paper coating developments for advanced gas turbine engines (diffusion aluminide coatings, overlay coatings, and ceramic thermal barrier coatings) were desorbed, a selection of current metallic coatings was made and their performance as outlined. Finally coating developments for advanced diesel engines with a view to improved turbocharging or to low heat rejection engines (adiabatic diesel concept) were dealt with. (IHOE).
Radiation technology offers a very wide scope for utilisation and commercial exploitation in various field. All over the world, this technology is being favourably considered for different applications like radiation sterilisation of medical products, preservation of food by controlling the physiological processes for extending shelf-life and eradication of microbial and insect pests, radiation processing of polymeric materials and treatment of sewage sludge. Bangladesh Atomic Energy Commission has taken radiation processing programmes in a big way right from its inception. This paper describes the studies carried out by various research groups in Bangladesh Atomic Energy Commission mainly using Cobalt-60 gamma radiation. The investigation covers medical sterilisation, food preservation and development and modification of polymeric materials by gamma radiation. ...
Abstract A miniaturized spatial temperature gradient CE system with automated sample introduction for DNA mutation detection was established. Continuous electrokinetic sample injection was achieved by combining an automated slotted vial array sample introduction device to the spatial temperature gradient CE system. The temperature gradient was produced by a radiative heating system with a single graphite block heater, and the stability of the temperature gradient was investigated. The temperature variation of each measure point was 0.12 0.21% RSD (n=7) within 6 h. A 14 cm Teflon AF coated silica capillary was used both as the separation channel and as the liquid core waveguide tube of fluorescence signal. Under a temperature gradient from 54.8 to 59.5 C, a low range control mutation standa...
Full text: Pigments possessing the ability to confer high solar reflectance have received considerable attention in recent years. The inorganic class of NIR reflective pigments are mainly metal oxides and are primarily employed in two applications: (i) visual camouflage and (ii) reducing heat build up. More than half of the solar radiation consists of near-infrared radiation (52%), the remaining being 43% visible light and 5% ultraviolet radiation. Over heating due to solar radiation negatively affects comfort in the built environment and contributes substantially to electrical consumption for air conditioning and release of green house gases. A pigment which has strong reflections in the NIR region (780-2500 nm) can be referred to as a 'cool' pigment. However, most of the NIR reflective inorganic pigments particularly yellow (eg. cadmium yellow, lead chromate, chrome titanate yellow etc.) contain toxic ...
To define the prognostic factors after surgical resection and evaluate the effectiveness of Post Operative Radiotherapy (PORT) in cases with cholangiocarcinoma, 44 cases with proximal cholangiocarcinoma were examined. The mean observation period was 20.6 months, and the survival rates 1, 3 and 5 years after the resection were 79.9%, 59.8% and 39.3%, respectively. Univariate analysis revealed that the presence of lymph node metastasis and absence of PORT were significant poor prognostic factors. Multivariate analysis revealed that the absence of PORT was a significant poor prognostic factor. The survival rates for 1 and 3 years after the resection were 80.0% and 40.0% in the curable A/B and PORT (-) group, and 100% and 53.3% in curable C and PORT (+) group. There were no local reccurences in the pathologically classified hm2 and em2 patients who underwent PORT. Even when the surgical margin is positive for the carcinoma pathologically, it is ...
The novolac type phenolic resins were synthesized and electron beam curing was carried out to the prepolymer obtained by the reaction of the phenolic resin and glycidyl meth acrylate in the presence of triethylbenzyl ammonium chloride. When the prepolymer and its mixtures with monomers were irradiated using electron beams at a dose rate of 3 Mrad/sec, the curing were completed at a dose 2.5 and 3 Mrad respectively. The effects of oxygen and that of hydroxyl group in the prepolymer on electron beam curing were also examined. (author).
Abstract in english We consider the three dimensional electromagnetic inverse scattering problem of determining information about a buried coated object from a knowledge of the electric and magnetic fields measured on the surface of the earth corresponding to time harmonic electric dipoles as incident fields. We assume that the buried object is a perfect conductor that is (possibly) partially coated by a thin dielectric layer. No a priori assumption is made on the extent of the coating, i.e. (more) the object can be fully coated, partially coated or not coated at all. We present an algorithm based on the linear sampling method and reciprocity gap functional for reconstructing the shape of the scattering obstacle together with an estimate of the surface impedance of the coating.
The fatigue properties of EP539LM alloy with an Al-Nb-Si fused slurry coating and a Co-Cr-Al-Y electron-beam coating are investigated experimentally in vacuum and in air at 900 C. It is found that the protective coatings reduce the fatigue life of the specimens both in vacuum and in air, with the electron-beam coating affecting the fatigue life of the alloy to a lesser degree than the fused slurry coating. The negative effect of the coatings on the fatigue life of the alloy is attributed largely to the properties of the coating material. 7 references.
A custom-built graphite-coated transmission ionization chamber is compared to the VacuDAP 2001 (VacuTec, Dresden, Germany), which has transparent conductive electrodes. A study was made of the dependence of response on x-ray tube potential for both types of chamber under identical conditions of exposure using over-table and under-table x-ray tubes. Since the calibration factor is the dose-area product of the radiation incident on the patient per chamber reading, it depends on the intrinsic response of the chamber as well as the effect of material in the beam between the x-ray tube and patient. Differences of about 20% were measured between the intrinsic and the over-table calibration factors and between the over-table and the under-table calibration factors for both chambers. The VacuDAP display is specifically calibrated for the over-table condition and would overstate the actual DAP in the under-table case. The intrinsic response of the ...
The performance of four different organic coating systems applied to carbon and weathering steel coupons has been assessed in this investigation. applied on the surface of carbon steel and weathering steel coupons. The coupons have been evaluated using five different tests, three field tests and two accelerated tests. The field tests were carried out at three atmospheric stations, located at COSIPA in Cubatao-SP, at Alto da Serra in Cubatao-SP and at Paula Souza in Sao Paulo city. The accelerated tests consisted of (a) exposure to alternate cycles of ultraviolet radiation/condensation combined with salt spray cycles (UVCON combined with Salt Spray) and of (b) exposure to alternate cycles of ultraviolet radiation/condensation combined with the Prohesion test. The performance of the coatings was assessed by visual observation and photographs, using a method based on ASTM D-610, ASTM D-714 and ASTM-1654 ...
In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.
In vitro cytocompatibility and cellular interactions of lauric acid and dextran-coated magnetite nanoparticles were evaluated with two different cell lines (mouse fibroblast and human cervical carcinoma). Lauric acid-coated magnetite nanoparticles were less cytocompatible than dextran-coated magnetite nanoparticles and cellular uptake of lauric acid-coated magnetic nanoparticles was more than that of dextran-coated magnetite nanoparticles. Lesser cytocompatibility and higher uptake of lauric acid-coated magnetite nanoparticles as compared to dextran-coated magnetic nanoparticles may be due to different cellular interactions by coating material. Thus, coating plays an important role in modulation of biocompatibility and cellular interaction of magnetic nanoparticles.
A chromium-free conversion coating for magnesium alloys were described. The conversion coating could be obtained when AZ31D magnesium alloy was immersed in a solution containing a manganese salt, phosphate and an inhibitor. Corrosion resistance of the chemical conversion coating was evaluated by anodizing polarization curve and salt immersion. XRD analysis showed that the conversion coating was mainly composed of Mn{sub 3}(PO{sub 4}){sub 2}. The morphology of the coating is observed by using SEM. The effect of electrolyte pH and concentration of inhibitor on coating growth are investigated. (orig.)
A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.
Low resolution visual polarimetric photographic imagery of the Galveston Bay oil spill from a tanker accident on July 28, 1990 was obtained and analyzed. The low resolution imagery (30 to 100 meters) was obtained concurrently with high resolution (1 meter), and is representative of what would be seen by a polarimetric satellite. Orthogonal red-green-blue (RGB) polarimetric images obtained with color photography were digitized by KODALUX on to a CD ROM. These polarimetric images were then used to calculate the percent polarization. The positive and negative percent polarized radiation scattered by each of the sea surface waves is seen individually in high resolution imagery. (Percent polarization is defined as positive when the dominant radiation is perpendicular to the plane of incidence and negative when it is parallel). The analysis of low resolution polarimetry is approached in a different manner than high resolution; in high resolution, ...
MCrAlY coatings are widely used on hot section components of gas turbines to provide hot corrosion and/or oxidation protection by formation of an oxide layer on the surface. As the protective oxide scale exfoliates during service, aluminum from the coating diffuses outward for reformation of the protective scale. Aluminum may also diffuse inward due to the differences in composition between the coating and the substrate. Thus, the coatings degrade due to oxidation, oxide scale spallation, and inward and outward diffusion of aluminum. Service life of these coatings is controlled by the aluminum content in the coating, operating temperature and start- shutdown cycles. In-service degradation of CoCrAlY and CoNiCrAlY coatings is presented. A procedure to predict the remaining service life of coatings under oxidizing ...
A critical review of the literature revealed no experiments on uranyl ion transfer from an aqueous to a tributyl phosphate phase which positively measured the kinetics of the chemical reaction at the interphase. Drawing isorhythmic lines on a three component diagram gives a complex correlation for the compaction of three sizes of glass beads. Neither the use of thoria sols nor high feed solution concentrations of thorium nitrate gave any significant increase in mean particle diameters over those obtained from nitrate solutions of lower concentrations in flame denitration. A hydraulic film resistance has been detected in the anion exchange of uranyl sulfate into Dowex 2lK, and chloride elution was found to give a higher apparent uranium diffusion coefficient than nitrate elution. The rate of dissolution of mixed thorium-uranium oxides was determined as a function of the per cent of mixed oxides dissolved. Mixing in tanks packed with boron glass Raschig rings ...
A cryocondensation pump was designed for the baffle chamber of General Atomics DIII-D tokamak and will be installed in the fall of 1992. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long and located in the lower outer corner of the vacuum chamber of the machine. It consists of a 1 m{sup 2} liquid helium-cooled surface surrounded by a liquid nitrogen-cooled shield to limit the heat load on the helium-cooled surface. The liquid nitrogen-cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. A thermal enhancement coating was applied to the nitrogen shell to lower the maximum temperature of the shell. The coating is non-continuous to keep the toroidal electrical resistance high. The whole pump is supported off the water-cooled vacuum vessel wall. ...
Technology of plasma sputtering, structure and properties of zirconium dioxide coatings were studied. Necessity of void number increase to enhance coating heat-resistance is shown. Optimal powder particle size (20-60 #mu#m) providing optimal coating porosity was determined. Weight part of stabilizating oxide (Y_2O_3) in ZrO_2 for formation in coating of microcracks serving as barriers for macro-cracks propagation was determined.
PVD-chromium-nitride coated samples of substrates of the magnesium alloy AZ91hp and the roller and ball bearing steel 100Cr6 were investigated regarding structure, mechanical characteristics, adhesion and internal stresses. For the coatings the parameters layer thickness and substrate BIAS voltage were varied. Both substrate materials were coated in one lad. Results of the X-ray analysis of the internal stresses show significant differences between the coated magnesium and the coated steel substrates. In the case of the variation of the substrate BIAS voltage, for the coated steel a dependency of the internal stresses to coating parameters could be obtained. For the coated magnesium no dependency was recognizable. The coating structure was examined with scanning electron microscopy. Element depth ...
An investigation was conducted to determine the cause of coating residue found in the test gun chambers during qualification firing of 120-mm combustible cartridge case (CCC) ammunition for the MlAl/A2 main battle tank. The CCC is coated with a clear epox...
A review of chemical decontamination methods for coatings indicates the following: the ease of both contamination and decontamination is a function of the radionuclide and the pH of the environment; the coating type is important in determining whether the contamination is loosely adsorbed, complexed, or contained in porous filler material; the condition of the coating is important to the decontamination factor obtained. Thus coatings can be decontaminated provided the solvent is sufficiently acid to solubilize the radionuclide and the complexant strength of the solvent is greater than that of the coating. Difficulties arise if the contamination is associated with fillers. Furthermore, though nothing has been said about temperature, decontamination of metal goes faster and, usually, with better efficiency at high temperatures. 11 references, 3 figures.
Abstract Background- Pemphigus vulgaris is a chronic disease not currently curable. Physical involvement and the impact of chronic therapies can lead patients to changes in psychological and relational areas. Objectives- To provide a measure of psychological distress, dysfunctional investment in one's appearance, and their relationship. Methods- Self-administered questionnaires (ASI, HADS) were given to 74 pemphigus inpatients. Results- Strong associations between psychological distress and dysfunctional investment in one's appearance were observed [adjusted odds ratio (OR) = 7.36, 95% confidence intervals (CI) 1.20-45.11; OR 5.38, 95% CI 0.81-35.87, respectively, for appearance stereotyping and body-image vulnerability], together with a perceived high disease severity (OR 6.03, 95% CI 1.9...
The patent describes a method for repairing leakage-causing cracks and fissures in a cryogenic heat exchanger. It comprises: reducing the interior pressure of the heat exchanger to a level which does not exceed the external pressure upon the hear exchanger while maintaining the temperature of the heat exchanger at a low level relative to the ambient external temperature; applying a curable liquid filler composition to the surface of the heat exchanger proximal the leakage site for seepage into the cracks and fissures located at the leakage. The composition upon a relatively short period of cure at low temperature forming a solid material which fills the cracks and fissures; curing the filler composition; and, applying a sealant composition to the surface of the heat exchanger at the filled leakage site. The sealant composition having long-term sealing performance under cyrogenic conditions.
Objective.The objective of this study was to use the newly synthesized poly(quaternary ammonium salt) (PQAS)-containing polyacid to formulate the light-curable glass-ionomer cements and study the effect of the PQAS on the compressive strength and antibacterial activity of the formed cements.Materials and methods.The functional QAS and their constructed PQAS were synthesized, characterized and formulated into the experimental high-strength cements. Compressive strength (CS) and Streptococcus mutans viability were used to evaluate the mechanical strength and antibacterial activity of the cements. Fuji II LC cement was used as control. The specimens were conditioned in distilled water at 37 degrees C for 24 h prior to testing. The effects of the substitute chain length, loading as well as gra...
The purpose of this study is to investigate the influence of tungsten carbide/carbon (WC/C) coating on the surface durability of casehardened steel gear. Two kinds of WC/C coatings were deposited on the ground gear pair made of chromium molybdenum steel with carburizing and quenching. One is the conventional WC/C coating, and the other is WC/C coating with about 1 ?m CrN interlayer. Here, the WC/C-coated test pinion and the WC/C-coated one with CrN interlayer are represented by WT and ST, respectively. Non-coated test pinion is represented by NT. The surface roughness along the tooth profile direction of WT and ST was almost the same as that of NT. A spur gear test was carried out with an IAE power circulating type gear test rig under EP gear oil lubricating condition. The fatal failure mo...
... Mirrors (Preprint) Ryan Conk et al. 15 September 2006 ... 4. TITLE AND SUBTITLE Stress Coatings for Large Scale Membrane Mirrors (Preprint) 5a. ...
A waterjet coating-removal system was developed at NASA's Marshall Space Flight Center in Huntsville, Ala., to remove thermal protective coatings from the ...
Ceramic coatings with high emission were fabricated on Ti6Al4V alloy by microarc oxidation (MAO) with additive FeSO4 into the electrolyte. The microstructure, chemical composition and chemical state of the coatings were determined by SEM, XRD, EDS and XPS, respectively. The bonding strength between the coating and substrate was studied by tensile strength test, together with the thermal shock resistance of the coating. The results showed that Fe content in the coating layer significantly affect its thermal emissivity. The relative content of Fe in the coatings surface increased at first and then decreased with increasing the concentration of FeSO4 in electrolytes, so does the emissivity of the coatings. The bonding strength became weaker with increasing the concentration of FeSO4. In addit...
Hexavalent chromium in corrosion preventive coating 64 ...To prevent corrosion of rims, weights can be provided with a coating. ...integrated clips brought up technical problems due to corrosion
Results showed that a simple yttrium coating offered more potential for ... was from 70 to 150 K (125' to 200' F) above that for the yttrium coating. ...
Novel in situ polymerizable liquid three-arm biodegradable oligomeric polyesters based upon glycolic acid (GA), L-lactic acid (LLA), and their copolymers are synthesized and characterized. Injectable and in situ curable polymer neat resins and their composites formulated with bioabsorbable beta-tricalcium phosphate are prepared at room temperature using photo- and redox-initiation systems, respectively. The cured neat resins show the initial compressive yield strength (YCS, MPa), modulus (M, MPa), ultimate compressive strength (UCS, MPa), and toughness (T, kN mm), ranging from 4.0 to 20.1, 201.5 to 730.2, 82.7 to 310.5, and 1.02 to 3.93. The cured composites show the initial YCS, M, UCS and T, ranging from 27.7 to 56.4, 1440 to 4870, 81.6 to 158.9, and 0.94 to 1.97. Increasing GA/LLA ratio increases all the initial compressive strengths of both neat resins and composites. Increasing filler content increases YCS and M but decreases UCS and T. A diametral tensile ...
This paper describes a feasibility demonstration of a thermal scanning NDE system for thermal spray coatings. Non-bonds were detected between several types of coatings and their substrates. Aluminum anti-skid coatings having very rough surfaces were included. A technique for producing known non-bond areas for calibrating and demonstrating NDE methods was developed.
The bibliography contains citations concerning the structural properties of sputtered tantalum and tantalum compounds. The preparation of thin film capacitors and resistors is described. The electrical properties of the sputtered films are also included. The influence of the substrate on the properties of the coatings is considered, including adherence of the coating to the substrate, and the effects of impurities on coating integrity. (Contains 250 citations and includes a subject term index and title list.)
Non-destructive methods for measuring the remaining anticorrosive or antioxidative ability of coatings are investigated. For anticorrosive chromium coatings the increasing ferromagnetism caused by loss of chromium is measured by a permeability probe. Measured values on blades after operation are correlated with the progress of corrosion as determined by metallographic methods. For antioxidative aluminum coatings the diminishing layer thickness is taken as indication for the exhaustion of their protection ability. The layer thickness is measured eddy current probes, especially developed for this application.
The structure and properties of composite powder coatings on the base of titanium carbide are studied. It is shown the electron-beam welding deposition of powders on the base of nickel and titanium carbide allows to produce of high-quality wear-resistant coatings which superior in density and hardness compared with sputtered ones. Changes of hardening phase volume percentage as well as composition of metal matrix make possible to control coatings hardness
Simulated atmospheric corrosion studies were performed to determine the corrosion protection provided by galvanized zinc coatings on depleted uranium, U-0.75 Ti alloy, and U-6 Nb alloys. The accelerated ASTM tests consisted of exposing the galvanized samples to aqueous and aqueous chloride environments. The test results showed that anodic protection was provided by the electronegative zinc coatings on uranium and uranium alloys. Treating zinc with chromate conversion coatings also provided more protection.
Aluminum hydroxide coating thicknesses were measured on fuel elements stored in aluminum canisters in K West Basin using specially developed eddy current probes . The results were used to estimate coating inventories for MCO fuel,loading. Brushing tests successfully demonstrated the ability to remove the coating if deemed necessary prior to MCO loading.
The effect of heat treatment on the corrosion behavior of reactive plasma sprayed TiN coatings in simulated seawater was investigated by electrochemical methods such as the corrosion potential-time curve (Ecorr-t), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and SEM, etc. The results showed that the corrosion potential of TiN coatings increased after heat treatment; the corrosion current of the TiN coatings after heat treatment (be hereafter referred to as HT-TiN) was 13.3% of the untreated coatings (be hereafter referred to as UT-TiN), and the polarization resistance of HT-TiN was 20 times of UT-TiN, which indicated that the heat treatment had significantly increased the corrosion resistance of the coatings. The corrosion behavior of the coatings was mainly ...
The Ti and Ti-Al coatings were deposited onto hot-worked AISI H11 steel substrates and plasma nitrided at 900 C. The Ti coated samples were successfully nitrided, while cracking and delamination of the Ti-Al coating was observed during nitriding. The formation of [delta]-TiN and [epsilon]-Ti[sub 2]N phases were detected after plasma nitriding of the Ti coating. During plasma treatment of the Ti-Al coating, the initial Ti[sub 3]Al and Al phases were paartially transformed into TiAl phase. The martensite transformation of the substrate material was found. The as-deposited Ti coating has a fibrous structure, while the structure of the as-sputtered Ti-Al coating is columnar. The superficial Vickers microhardness of plasma-nitrided Ti coating was 2200 HV 0.03 and the critical load of higher than 50 N indicates very good ...
There is an increasing number of applications for hard coatings in engineering where the properties of the single-layer coating are not sufficient. One way to solve this problem is to use a multilayer coating that combines the properties of several coating materials. In this study, TiN-CrAlN and CrN-CrAlN multilayer coatings were deposited on 100Cr6 and S6-5-2 (DIN) steel substrates, by means of unbalanced magnetron sputtering. For comparison, TiN, CrN and CrAlN single-layer coatings were also prepared. For all depositions the coating temperature was below 473 K. Indentation testing, hardness measurements and scratch tests were performed to characterize the mechanical properties. The correlation between the wear behavior in rolling contact and the mechanical properties of the multilayer coatings is reported. A ball ...
In situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol.dm"-"3 Ce(NO_3)_3, La(NO)_3 and Sm(NO)_3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well-polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of ...
From a macroscopic point of view, corrosion of Zn alloy coated steel sheet occurs by the coating preceding corrosion mechanism; microscopically, however, the coated layer corrosion velocity in the tip of corrosion is different. In order to find the main factors of under-film corrosion of Zn and Zn-Fe alloy coatings in the salt water spray atmospheric exposure test, the correlation between point inflation-exfoliation width and chlorine penetration behavior, point adhesion, and the difference in chlorine penetration behavior due to alloy coating components were investigated. Consequently, the following results were obtained: 1. The better correlation was observed between chlorine penetration distance and point inflation-point exfoliation width. 2. The durability of coating against chlorine penetration improved by increase in point adhesion and Zn content in the ...
For the protection of buried steel pipeline, it is common practice to coat the pipelines with highly insulating coating and apply a cathodic current to insulate the pipe from the aggressive environment. Cathodic current protects holidays or damaged area of coating which required less current than would be needed for an uncoated pipe, but because of the cathodic reactions evolution will be taken H{sub 2} and OH{sup -} on holidays which exposed metal to the environment place. This effect is to cause loss bond of coating around the holidays called cathodic dis-bonding. In this paper we measured cathodic dis-bonding of three types of coatings at - 1.5 V(Cu/CuSO{sub 4}) according to ASTM G8. We studied on cathodic dis-bonding resistance of petroleum-base, coal tar-base and polyethylene plastic tape coatings. After 30 days immersion in electrolyte it was found that ...
Ellipsometric studies and reflectance measurements on five anodized coloured 304 stainless steel samples (Brown, Violet, Blue, Light Grey and Dark Grey) are reported. The optical properties, solar absorptance and thermal emittance of samples have been obtained. Measured values of absorptance lay between 0.75-0.87 together with a near normal emittance value approx. =0.10 at 100/sup 0/C. The total hemispherical emittance has been measured at 100 and 200/sup 0/C for the sample having the best selective surface. This study shows that the blue coloured surface has the most favourable combination of radiation properties. The surface deteriorates at temperatures above 210/sup 0/C. Oxidation is assumed to be the deterioration mechanism. The different samples exhibited difference in the /PSI/ and ..delta.. parameters as determined by ellipsometry both before and after heat treatments. When brown and violet samples were coated with a 125 nm layer of ...
This article described a full-scale green renovation project undertaken by a construction management firm in Newton, Massachusetts. Chapman Construction and Design began renovating its own office building in late 2007 and completed it in September 2008. The firm set out to achieve LEED Platinum certification from the United States Green Building Council. The project involved energy saving modifications to its mechanical systems; replacing plumbing fixtures with high efficiency alternatives to reduce water consumption by at least 40 per cent; installing skylights and additional windows to allow more natural light into the interior space; salvaging doors, lighting, metal studs and masonry whenever possible; and using sustainable products such as recyclable carpets, tiles and low-VOC paint. The main feature of the renovation was a new 47 kW (DC) photovoltaic (PV) solar power array installed on the rooftop. The PV array includes 208 panels and a SunPower SPR-225 system that produces 55,000 ...
The Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI-2 Reactor Building during February and March 1982 and was designed to investigate the effectiveness of various surface decontamination techniques. The polar crane, D-rings, missile shields, refueling canal, fueling bridge, major equipment, floors and some walls were flushed with low pressure water. Water lances were directed manually and applied water at temperatures between ambient and 60"0C at a flow rate of about 95 liters per minute. In addition, floor surfaces on the 305-ft elevation and floor surfaces and major equipment on the 347-ft elevation were sprayed with high pressure water (floors in the Reactor Building are designated by their elevations above sea level). The water pressure in this case varied between 13.8 and 41.4 mPa and water temperature was at a maximum 60"0C. Certain surfaces were also decontaminated using either strippable coatings or a mechanical ...
The electrical conductivity of Vitox-alumina (99.2%), Wesgo-alumina (99.9%) and AlN (99.6%) has been measured during and after irradiation with an experimental set-up which allows fusion relevant loading conditions. All irradiations were performed in high vacuum at 450 C using a 104 MeV {alpha}-particle beam with an applied DC electric field of 100 kV/m. In the high purity Vitox-alumina the in-situ and postirradiation bulk conductivities {sigma} and {sigma}{sub 0} show the highest irradiation induced electrical breakdown ever observed. The saturation level near 4 x 10{sup -2} ({Omega}m){sup -1}, reached already after 0.015 dpa (O-sublattice), is already above the critical value necessary to avoid MHD pressure drop with 10 {mu}m coatings in flowing liquid metal coolants. Under the same conditions no radiation induced electrical degradation at all has been found in Wesgo-alumina and AlN. (orig.).
Decommissioning of radiological and nuclear installations is for this century the new challenge. One of the performance criteria is the reduction of total quantities of radioactive materials (liquid or solid) arising from dismantling and decontamination of radiological and nuclear installations. In this work we present a new application of the water soluble polymers used as: - flocculation agents in treatment and conditioning process within the management of radioactive liquid materials; - strippable coatings on solid materials based on the water soluble polymers. The parameters of water soluble polymers made in our Institute by radiation processing have been analysed, namely the molecular average weight, composition, and efficiency of utilization of these polymeric materials as well as the content of ash, additives, decontamination factor, consumption per surfaces/liter, corrosion aspects, compatibility with various surfaces (of metal, ...
Aluminum nitride has been proposed as electrically insulating coating in connection with blankets made of vanadium alloys. Irradiations were performed with an applied DC electric field of 100 kV/m, using a 104 MeV {alpha}-particle beam. The dose achieved were 0.1 dpa at 300 C, 0.05 dpa at 400 C, and 0.06 dpa at 500 C. The out-of-beam conductivity {sigma}{sub 0} decreased at all temperatures employed during early stage of irradiation. Before 0.02 dpa had been reached, {sigma}{sub 0} dropped to low values of typically (2-4) x 10{sup -11} ({Omega} m){sup -1}. Although a moderate increase can be observed during further irradiation, {sigma}{sub 0} remained below the initial value of the unirradiated specimen for all temperatures. That is, there is no significant evidence for radiation induced electrical degradation. The in-beam conductivity {sigma}, measured continuously during irradiation, also decreased by at least one order of magnitude. Relevant ...
Hybrid organic-inorganic coatings with phosphonate functionalities have been synthesized and evaluated as prospective surface treatments for magnesium materials. These coatings have been processed via a sol-gel route by hydrolysis and condensation of a mixture of diethylphosphonatoethyltriethoxy-silane and tetraethoxy-silane with variable molar ratios. The coatings morphology and the surface chemistry at the coating/substrate interface have been characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, "3"1P nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry. The corrosion protection performance of the coatings deposited on magnesium alloy AZ31B has been examined by a group of electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, a scanning Kelvin ...
This paper describes the effects of SiC coating on the oxidation resistance of C/C composites in combusting fields, which are expected to be applied to high temperature structural materials at over 1770K. The coating methods employed were CVD and pack cementation. The time changes in weight loss of the specimens were measured at temperatures of 1770K and 1900K under the equivalence ratio of 0.9 generated by methane-air combustion, and the surface of the specimens before and after the experiment was observed by SEM. Although the weight loss of the specimens coated by the CVD method was minimal, the coating layer was easily peeled off from the substrate. On the other hand, the layer of the specimens coated by the pack cementation method was stable and adhered to the substrate, but the substrate was degraded because of penetration of oxygen through the pores in the layer. To cover the ...
In the framework of the European Fusion Technology Programme ECN participates in a NET task PSM-8 `Coatings and Surface Effects on Stainless Steel 316L`. High emissivity coatings were developed for enhanced heat transfer from graphite tiles to a Stainless Steel First Wall. Four candidate materials, Cr{sub 2}O{sub 3}, Black Cr, Al{sub 2}O{sub 3}/TiO{sub 2} and TiC were tested as candidate high emissivity coatings. These coatings were manufactured by atmospheric and vacuum plasma spraying technique and the Black Chromium coatings were manufactured by a galvanic coating technique. The tests included total emissivity measurements and Low Cycle Fatigue (LCF) experiments. The total emissivity of two TiC coatings at 525 K appeared to be 0.62 and 0.64. The total emissivity of the TiC and 5 wt% TiO{sub 2}/Al{sub 2}O{sub 3} ...
In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 {mu}m thick nitride compound layer was formed in surface region and the same thick carbide compound layer was also formed ...
In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 #mu#m thick nitride compound layer was formed in surface region and the same thick carbide compound layer was also formed ...
Phosphate/chromate and accelerated chromate coatings were produced on commercially available aluminium. The Cr, P and Fe components of the conversion coatings were determined by radioactive tracer technique. The tracer technique was combined with ion-exchange and film-sectioning methods to determine the chromium(III)/total chromium ratio in the accelerated chromate coating. It was found that during the acidic dissolution of the conversion coating the chromium(III)/total chromium ratio may suffer changes. The film-forming components in the metal/bath interface are supersaturated and deposited onto the aluminium. The identified components of the accelerated chromate coatings are Cr(OH)sub(3), Cr(OH)CrOsub(4) and Crsub(4)(Fe(CN)sub(6))sub(3) and the chromium(III)/total chromium ratio was found to be cca. 2/3. (author). 11 refs.; 5 figs.
In situ composite coating of hydroxyapatite (HA)/TiO2 were produced on titanium (Ti) substrate by micro-arc oxidation coupled with electrophoretic deposition (MAO&EPD) technique with different concentrations of HA particles in the 0.2M NaOH electrolyte solution. The surface morphology and chemical composition of the hybrid coating were effected by HA concentration. The amount of HA particles incorporated into coating layer increased with increasing HA concentration used in the electrolyte solution. The corrosion behavior of the coating layer in simulated body fluids (SBF) was evaluated using a potentiodynamic polarization test. The corrosion resistance of the coated sample was increased compared to the untreated Ti sample. The in vitro bioactivity assessment showed that the MAO&EPD treated...
The electroless nickel plating/poly(dl-lactide-co-glycolide) composite coating (EN-plating/PLGA composite coating) was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy AZ81 to double control the corrosion and drug release in the hanks' solution. The EN-plating was fabricated on the MAO coating to improve the corrosion resistance by overlaying most pores and micro-cracks on the surface of the MAO film. Meanwhile, a double layered organic poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) drug releasing coating with a top layered PLGA drug controlled releasing coating on EN plating was prepared to control the drug release rate by adjusting the different lactide: glycolide (LA:GA) ratio of PLGA. Scanning electron microscopy (SEM) and the X-ray powder dif...
Assembly of icosahedral capsids of proper size and symmetry is not understood. Residue F170 in bacteriophage P22 coat protein is critical for conformational switching during assembly. Substitutions at this site cause assembly of tubes of hexamerically arranged coat protein. Intragenic suppressors of the ts phenotype of F170A and F170K coat protein mutants were isolated. Suppressors were repeatedly found in the coat protein telokin-like domain at position 285, which caused coat protein to assemble into petite procapsids and capsids. Petite capsid assembly strongly correlated to the side chain volume of the substituted amino acid. We hypothesize that larger side chains at position 285 torque the telokin-like domain, changing flexibility of the subunit and intercapsomer contacts. Thus, a sing...
Several metallurgical coatings have been developed that provide good tribological performances in high-temperature liquid sodium and that are relatively unaffected by neutron fluences to 6 X 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). The coatings that have consistently provided the best tribological performance have been the nickel aluminide diffusion coatings created by the pack cementation process, chromium carbide or Tribaloy 700 trade mark (a nickel-base hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing materials applied by the electro-spark deposition process. The latter process is a relatively recent development for nuclear applications and is expected to find wide usage. Other coating processes, such as plasma-spray coating, sputtering, and ...
The purpose of this study was to synthesize biocompatible polyvinylpyrrolidone (PVP)-coated iron oxide (PVP-IO) nanoparticles and to evaluate their efficacy as a magnetic resonance imaging (MRI)...Full Text Available
Duplex-coating procedures consisting of plasma nitriding and Me-C:H hard coating lead to an improved performance of the devices because the Me-C:H coating is supported by the nitrided phase and, therefore, the `eggshell-effect` is avoided. Furthermore, this support leads to a higher load-bearing capacity of the thin film. Two standard procedures (classical high-pressure plasma nitriding and unbalanced magnetron sputtering of Ti-C:H) were performed subsequently to prepare the duplex coatings on X20Cr13 ferritic stainless steel. The corrosion resistance of the steel could be improved by nitriding at 450 C compared to the untreated ferritic substrate. The roughness is determined by the nitriding step. The weakest point of the coating is the transition zone between the nitrided and the untreated substrate and not the interface between the Ti-C:H coating and the ...
The objective of this work was to evaluate the physical properties and in vivo circulation of chitosan (CH)-coated liposomes of mitoxantrone (MTO). Changes in particle size and zeta...Full Text Available
A serological trapping technique for detecting rotaviruses is described which involves coating electron microscope grids with protein A and specific rotavirus antiserum. The presence of a layer of antibodies...Full Text Available
Computer-assisted analysis revealed a striking sequence similarity between the putative 24-kDa protein (p24) encoded by open reading frame (ORF) 5 of beet yellows closterovirus and the coat protein...Full Text Available
The metal-semiconductor solar cell is a potential candidate for converting solar energy to electrical energy for space and terrestrial application. In this paper, a method for obtaining parameters of practical antireflection (AR) coatings for the metal-semiconductor solar cells is given. This method utilizes the measured equivalent index of refraction obtained from ellipsometry, since the surface to be AR coated has a multilayer structure. Both the experimental results and theoretical calculations of optical parameters for Ta/sub 2/O/sub 5/ AR coatings on Au-GaAs and Au-GaAs/sub 0.78/P/sub 0.22/ solar cells are presented for comparison. (AIP)
A report is given on an improved filler-binder mixing method in the manufacture of artificial graphite, the so-called coat-mix process. The individual graphite-filler grains are coated completely with uniform binder coatings (phenol formaldehyde resin) in a continuous process. Methanol is used as solvent for the resin. In a modified further development of the process, the use of organic solvents can be disregarded by dissolving the binder resin in caustic soda and injecting the slurry into water diluted acid. The manufacture of casting molds from coat-mix powders, their properties and industrial application are given. Finally, the advantages of using carbon bodies of coal-mix material for conversion to silicon carbide are indicated. (IHOE).
New data about the structure of high-temperature resistant metalloceramic plasma sprayed coatings in micro and nano areas are presented. Application of the new instrumental methods: transmission electron microscopy combined with selected area electron diffraction mode is possible to obtain these data. The first layer in Ni based metallic bond coat shows nanocrystalline structure. External ceramic layer based on stabilised ZrO_2 is polycrystalline and contains both cubic and tetragonal crystalline phases. Local inhomogeneities in coatings phase composition are determined. (author)
The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces that are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate triode sputtering methods are discussed. In addition to substrate temperature, the bcc-to-beta phase ratio in sputtered tantalum coatings is shown to be sensitive to other substrate surface effects.
There is increasing demand to functionalize meso- and nano-porous materials by coating and make the porous substrate biocompatible or environment friendly. However, coating on a meso-porous substrate poses great challenges, especially if the pore aspect ratio is high. In the current work the pulsed laser deposition (PLD) method is used for coating Ni{sub 3}Al-based meso-porous membranes with diamond-like carbon (DLC) layers of high thickness homogeneity and adhesion. (orig.)
The theoretical principles underlying the formation of oxide and, in particular, anodic oxide coatings on metals produced by chemical oxidation, anodizing in solutions, and anodizing in cold plasmas are reviewed. The mechanisms and conditions of anodic oxidation are described, and the structure of anodic oxide coatings on aluminum, magnesium, beryllium, zinc, cadmium, iron, cobalt, nickel, titanium, zirconium, tantalum, and chromium alloys is examined. Attention is also given to various applictins of anodized coatings. 54 references.
With the deposition of PVD hard coatings on the tools applied in machining operations it is possible to achieve significant improvements in the performance and quality of the machining processes. Depending on the machined material and the operating principle, e.g. turning, milling or drilling, not only different machining parameters but also different coating materials are necessary. In interrupted cut machining of tempered steel, for example, the life time of Ti-C-N coated inserts is several times greater than the Ti-C-N coated ones. This is a result of the favourable thermophysical and tribological properties of Ti-N-C. The potential for tool protection by CrN coatings is a result of the high ductility and low internal stress of this coating materials. CrN films can be deposited with greater film thickness, still maintaining very good adhesion. This paper ...
The cathodic vacuum arc provides a means of producing large currents of positive ions of a wide variety of materials. These ions can be utilized to produce coatings with improved properties such as higher density and adhesion. The processing is particularly useful in reactive deposition of ceramic coatings having excellent stoichiometry. In this review, emerging aspects of the technology are emphasized.
The method of production of xAl{sub 2}O{sub 3}-yTiO{sub 2} compositions provides for the depth distribution of coating components and specifies its mechanical properties. In case of the composition obtained by cladding, titanium is mainly concentrated at the substrate. In case of mechanical mixture or composition obtained by sintering the oxides, the depth distribution of coating components is random.
The method of the present invention comprises a step of previously coating a positive type resist on the surface of equipment, a step of solidifying the coated positive type resist and a step of bringing the coated equipment to circumstances for use and cleaning the positive type resist. With such procedures, the amount of radioactive materials deposited on the equipment can be reduced, and redeposition of nuclides on the surface to be cleaned can be prevented. (T.M.)
Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride (BF3)-filled proportional counters, 2) Boron-lined ...
Tungsten (W) coating on fusion candidate V-4Cr-4Ti (NIFS-HEAT-2) substrate was demonstrated with plasma spray process for the purpose of applying to protection of the plasma facing surface of a fusion blanket. Increase in plasma input power and temperature of the substrate was effective to reduce porosity of the coating, but resulted in hardening of the substrate and degradation of impact property at 77 K. The hardening seemed to be due to contamination with gaseous impurities and deformation by thermal stress during the coating process. Since all the samples showed good ductility at room temperature, further heating seems to be acceptable for the vanadium substrate. The fracture stress of the W coating was estimated from bending tests as at least 313 MPa, which well exceeds the design stress for the vanadium structure in fusion blanket. (author)
Research highlights: ? Reports a high protection system for the alloy in corrosive environment. ? Describes an interfacial process with self-healing properties. ? Reports the influence of substrate pre-treatment in the coating performance. - Abstract: In this paper the interface of poly(vinylidene fluoride) coatings prepared by the dip coating method and HF-treated AZ31 magnesium alloy was evaluated. The best performance of this system in corrosion tests compared to ground, as-received and acetic acid cleaned substrates is related to an acid-base interaction at the interface and to interfacial reactions which resulted in a self-healing process. The protectiveness of the samples was investigated using impedance and immersion tests while the coating morphology and interface stability were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy and adhesion tests.
This study investigated the effect of board type (unmodified vs. MAPE modified) on the surface quality and thickness swelling-water absorption properties of recycled high density polyethylene (HDPE) based wood plastic composites. Additionally, two commercially available coatings (cellulosic coating and polyurethane lacquer coating) were also applied to composite surfaces and their adhesion strength, abrasion and scratch resistance, and gloss values were determined. This study showed that modification of the composites with MAPE coupling agent increased the surface smoothness and reduced the water absorption and thickness swelling of the panels. Abrasion resistance of the composites was also improved through MAPE modification. Regardless of board type, higher scratch resistance and gloss values were observed for polyurethane lacquer coated samples compared to those of cellulosic varnish ...
The effect of the coated composite surface of particles on the mechanical properties of the powder bed was investigated. Polyethylene-silica surface composite powder was prepared at several coating ratios with Hybridizer. Various tests on mechanical properties of the powder bed were carried out with the prepared powder, and the following results were obtained: The ultimate tensile strength depends only on the cohesive force between particles, and the contact probability model of composite particles led to good agreement between the experimental and calculated values. The coefficient of internal friction and cohesive shear strength were influenced due to the interlocking effect of the surface roughness of composite particles. The effects of coating particles became small with dynamic properties like angle of repose. It is possible to control the mechanical properties in a step wise fashion by changing the ...
Experiment was conducted to study the effect of gamma irradiation, growth retardants and coatings (coconut oil, mustard oil and liquid paraffin) on shelf life of winter guava fruits during storage. The results revealed that the superiority of coconut oil coating over other post harvest treatments. Physiological loss in weight (7.1%), marketable fruits retained over control (86.7%), total soluble solid (16.1%), ascorbic acid (195 mg/100 g pulp) and total sugar (10%) of fruit were positively influenced by coconut oil coating up to 12 days of storage. The treatment was found significantly effective in increasing the post harvest life of fruits for 12 days over control without adversely affecting the fruit quality. Coconut oil coating gave highest consumer acceptability while, maintaining suff...
Analysis reproducibility and detection sensitivity of capillary electrophoresis (CE) are often questioned by applied scientists, which has hindered its application as a routine method. To address these issues, a simple, precise, and reproducible dynamic coating method was developed by applying carboxymethyl chitosan (CMC) dynamic coating on fused silica capillary. The proposed coating was accomplished by simply rinsing the capillary with CMC solution for 1?min in between runs, with no regeneration procedure or buffer additives needed. Electroosmotic flow could be well controlled by adjusting the pH of background electrolyte, and the adsorption of analytes onto the capillary inner wall was effectively eliminated. The main parameters of the coating condition were optimized, and extensive app...
The purpose of this study was to investigate whether hydroxyapatite (HAp) coating could induce polyethylene terephthalate (PET) artificial ligament graft osseointegration in the bone tunnel. Twenty-four New Zealand white rabbits underwent artificial ligament graft transplantation in bilateral proximal tibia tunnels. One limb was implanted with HAp-coated PET graft, and the contralateral limb was implanted with non-HAp-coated PET graft as control. The rabbits were randomly sacrificed at four and eight?weeks after surgery. The loads to failure of the experimental group at eight?weeks were significantly higher than those of the control group (p?=?0.0057). Histologically, application of HAp coating induced new bone formation between graft and bone at eight?weeks compared with the controls. Rea...
Ion storage CeO{sub 2} and CeO{sub 2}/SnO{sub 2} coatings were prepared by sol-gel dip-coating method using aqueous-based process. The influence of added SnO{sub 2} in the CeO{sub 2} oxide coatings on the inserted/extracted charge was determined by chronocoulometric measurements. It was found that for 60 nm thick film the inserted/extracted charge was twice larger (Q = 10mC/cm{sup 2}) for films containing 17 mol % SnO{sub 2} if compared to pure CeO{sub 2}. The addition of SnO{sub 2} to the mixed oxides coatings on their optical properties and structural characteristics were studied.
The carbon fibers (CF) were pre-treated in two different ways: no pre-treatment, and activation in HNO3 plus application of toluene-2,4-diisocyanate (TDI). Carbon fibers have been introduced into polyurethane (PU) composite coatings. The tribological behaviors of the polyurethane composite coating filled with CF or TDI-modified CF (TDI-CF) were studied using a ring-on-block wear tester under dry sliding, and the worn surfaces of the filled PU coatings and transfer films formed on the surface of the counterpart ring sliding against the PU coating were investigated by SEM and optical microscope (OM), respectively. Owing to the effective improvement of the interfacial adhesion between the CF and polyurethane matrix, compared with the cases of untreated CF, the employment of low content TDI-CF...
We have developed efficient spectrally selective infrared (IR) emitters that can be utilized for thermophotovoltaic (TPV) power generation by using stainless steel (SUS304) substrates coated with b- FeSi2 thin films. To develop spectrally selective emitters, we theoretically propose antireflection (AR) coatings consisting of a single layer of a dielectric material having a high refractive index (~5) and are appropriate for use with metals such as stainless steels in the IR region. This type of AR coating is fabricated by sputtering a b- FeSi2 thin film on a polished SUS304 substrate. The reflectance in the IR region is successfully reduced to less than 10%. In addition, the AR properties are stable even at 700 K in air. Therefore, metals with AR coatings of b- FeSi2 can be applied to IR em...
Abstract Introduction.- Infection is the worst complication seen with inflatable penile prosthesis (IPP). Both the American Medical Systems (AMS) and Coloplast IPP have infection retardant coatings. AMS is coated at the factory with rifampicin and minocycline (InhibiZone). The Coloplast IPP has a hydrophilic coating covalently bonded to its components that will absorb any aqueous solution before implantation and provides increased surface lubricity to decrease bacterial adherence. Aim.- We tested several antibiotic dips comparing zones of inhibition (ZOI) against five commonly infecting bacteria with coated Coloplast implants. Results were compared with those ZOI created with strips of an AMS IPP precoated with InhibiZone. Methods.- Pieces of sterile Coloplast Titan IPP were dipped in (i) ...
We analyse numerically the acoustic stop band properties of an array of orthotropic coated cylinders whose elastic parameters are deduced from a geometric transform [H. Chen, C.T. Chan, Acoustic cloaking in three dimensions using acoustic metamaterials, Appl. Phys. Lett. 91 (2007) 183518]. We find that whereas a single coated inclusion is acoustically neutral at any frequency, an array of them might display some stop bands. More precisely, an array of freely vibrating coated voids is always neutral, whereas an array of clamped coated inclusions might display a zero frequency stop band. Interestingly, an array of radially symmetric coated inclusions behaves as local Helmholtz resonators, for which the eigenfield within each cloak is obtained in closed form, leading to a frequency estimate a...
The combined processes of plasma nitriding and cathodic arc deposition of (Ti,Cr,Nb)CN coatings were applied to HSS substrates. The nitrided layers, obtained in a mixture of H2 (70%) and N2 (30%) at two different temperatures (480^oC and 510^oC), were examined for the microhardness depth profiles. Characterization of the duplex coatings was performed by investigating elemental and phase composition, texture, hardness, friction and wear. XRD and XPS analyses revealed the formation of a mixture of a carbonitride fcc solid solution, in a dominant proportion, and metallic chromium. The film hardness was measured to be ~34GPa. The duplex (Ti,Cr,Nb)CN coatings exhibited superior tribological behavior as compared to both nitrided layers and non-duplex coatings.
The physical, chemical and mechanical properties of magnesium alloys make them attractive materials for automotive and aerospace applications. However, these materials are susceptible to corrosion and wear. This work discusses the potential of using sol-gel based coatings consisting of ZrO_2 and 15 wt.% of CeO_2. The CeO_2 component provides enhanced corrosion protection, while ZrO_2 impart corrosion as well as wear resistance. Coating deposition was performed by the dip coating technique on two magnesium alloy substrates with different surface finishes: AZ91D (as-casted, sand-blasted, and machined) and AZ31 (rolled and machined). All as-deposited coatings (xerogel coatings) were then subjected to 10 h annealing: a temperature of 180 C was applied to the AZ91D alloy and 140 C to the AZ31 alloy. Morphological and structural properties of the annealed coatings ...
A Ni3Al coating was prepared by plasma spraying technique on the surface of titanium alloy. Ni-Al mixed powders, coatings and reaction products were investigated by scanning electron microscope, EDS, DSC and XRD. A tight bonding between the coating and the substrate was formed. The X-ray diffraction analysis of the patterns showed that the coating not only had Ni3Al phase, but also had NiO and Al2O3 phase microcontent. Comparing Ni coated Al to Ni3Al at 900^oC, the diffusion was stronger and the diffusion layer was thicker. A minute pore structure was formed at 1200^oC in the front edge of solid-state reaction layer. So Ni3Al restrained the solid-state reaction of the coating with the substrate, and as a whole weakened the entry of oxygen atoms into the substrate and quenched the out-diffu...
A focused ion beam (FIB) technique was applied to cross-sectional specimen preparation to observe an interface between a plasma sprayed coating and an aluminum (Al) substrate by transmission electron microscopy (TEM). The surface of the sprayed coating film has a roughness of several tens of microns. Sputter rates for the coating film and the substrate are greatly different. The rough surface and the difference in sputter rate cause problems in making TEM specimens with smooth side walls. The top surface of the coating film was planerized by the FIB before fabricating the TEM specimen. The interfaces were investigated by TEM and energy-dispersive X-ray (EDX) analysis. The TEM observation revealed that there is a 10 nm thick amorphous layer at the interface between the coating film and substrate. The coating film consists of two kinds of sublayers with bright and ...
There is presently considerable interest in wear resistant coatings produced using closed field unbalanced magnetron sputtering technology. For example, layered films of diamond-like carbon (DLC) with tungsten or titanium additions have been widely reported. The benefit is that the mechanical properties are enhanced (e.g. giving greater toughness); also it is possible to control the stress state and enhance adhesion. Here we report the further development of this concept by the addition of TiN, TiCN and TiC layers in DLC-based composites, utilizing an additional source of electrons in the vicinity of substrate to enhance ionisation of the plasma and increase coating density. Composite coatings of ceramics TiN, TiC{sub x}N{sub y}, TiC, CrN, TiCrN, TiCrCN, TiCrC, metal doped Ti{sub x%}-DLC and their combinations were deposited on 316 stainless steel substrates. The mass flow of reactive gases into the chamber was controlled ...
Copper coatings deposited on Al-6061 substrates by radio frequency magnetron sputtering, to prevent the retention and permeation of energetically implanted tritium in Al-6061, were evaluated by a variety of characterization techniques. The coatings, weighing in the 0.03 to 0.088 kg/m{sup 2} range, were smooth and had a fine grain structure. They contained the intermetallic phases Cu{sub 9}Al{sub 4} and CuAl{sub 2} as well as copper. The fractions of Al and Cu in any coating increased and decreased, respectively, with increasing depth below the surface. Furthermore, the fractions of Al and Cu on the coating surface decreased and increased, respectively, with increasing coating weight. There was no texture or preferred orientation in the Cu phase of the coatings. A significant amount of oxygen was also detected at the original substrate surface. Residual stress ...
Research highlights: The dental implant of titanium could be modified by anodic oxidation. It was found that incorporation of strontium ions into the matrix increase the bone formation. In this study, we try to investigate the effect of corrosion property and bioactivity on coatings containing strontium by anodic oxidation. The results suggest that coatings containing strontium on titanium by anodic oxidation has the potential to show the stability and bioactivity in the clinical use. - Abstract: Pure titanium (Ti) and titanium alloys are considered as bio-inert materials in clinical use. Bioactivity is the ability to induce bone-like apatite on the material surface. The micro-arc oxidation (MAO) technique is an effective method for improving the surface properties of titanium. The aim of this study was to investigate the bioactivity and corrosion behavior of MAO coatings containing strontium, which is beneficial for ...
Abstract The authors provide a survey of how images are used in radiation therapy to improve the precision of radiation therapy plans, and delivery of radiation treatment. In contrast...Full Text Available
... radiation during clinical therapy and exposures due to radiation accidents or attacks, in which the doses are uncontrolled ... only be used off-label in victims of radiation accidents or attacks. The idea...
Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no ...
This paper describes an investigation of electrodeposited Zn-14% Ni and aluminium-based SermeTel 1140/962 coatings as possible replacements for cadmium. Slow strain rate tests were performed to measure the extent of direct hydrogen embrittlement of a high strength steel substrate as a result of the coating process and of hydrogen re-embrittlement caused by coating corrosion. The level of re-embrittlement was shown to depend on both the electrochemical potential of the coating and its barrier properties. Zn-14% Ni coatings caused the most re-embrittlement as they had the most active potential and contained through-thickness defects which left the steel exposed to hydrogen uptake. The microstructure of the high strength steel was also shown to be an important factor affecting the extent of embrittlement. AerMet 100 steel was more resistant than 300M steel and this was attributed to ...
Today, as a result of increase in oil prices, limited fossil fuel resources, environmental consideration and global warming, the methyl ester fuels have been focused on alternative fuels. Methyl ester fuels can be used more efficiently in low heat rejection engines (LHR), in which the temperature of combustion chamber is increased by creating a thermal barrier. In this study, the piston, cylinder head, exhaust and inlet valves of a diesel engine were coated with the ceramic material Al{sub 2}O{sub 3}-TiO{sub 2} by the plasma spray method. Thus, a thermal barrier was provided for the parts of the combustion chamber with these coatings. The effects of corn oil methyl ester that produced by the transesterification method, and No. D2 fuels' performance and exhaust emissions' rate were studied by using equal in every respect coated and uncoated engines. Tests were performed on the uncoated engine, and then ...
Several types of coatings have previously been visually identified on the surface of 105-K East and 105-K West Basins fuel elements. One type of coating (found only in K West Basin) in particular was found to be a thick translucent material that was often seen to be dislodged from the elements as flakes when the elements were handled during visual examinations (Pitner 1997). Subsequently it was determined (for one element only in a hot cell) that this material, in the dry condition, could easily be removed from the element using a scraping tool. The coating was identified as Al(OH){sub 3} through X-ray diffraction (XRD) analyses and to be approximately 60 {micro}m thick via scanning electron microscopy (SEM). However, brushing under water in the basin using numerous mechanical strokes failed to satisfactorily remove these coatings in their thickest form as judged by appearance. Such brushing was done ...
This report outlines on the corrosive damage which is inherent to a high temperature environment and introduces on thermal spraying system taking an example of a gas turbine. The recent coatings by thermal spraying for high temperature environment are positively used in such applications as a hearth roll for continuous annealing, a roll for hot dipped steelplate, a solid electrolyte for fuel cell, boilers and rockets. The coating formed will be positively used because of a convenient thermal spraying and availability of various sprayable materials. This report describes the following items. Corrosive damage under the high temperature environment. Types of high temperature corrosive coating by a thermal spraying and utilization thereof. Outline of MCrAlX alloy, and merits thereof. Coating to a turbine wing by rduced pressure plasma thermal spraying. In general, it is urgently needed to establish the ...
The photon rupture method, by which oxide film and metal are removed by focused pulsed Nd-YAG laser beam irradiation, was applied to form artificial micro-pits in Zn-5 mass% Al alloy-coated steel. The zinc alloy-coated layer was removed by pulsed laser irradiation treatment for about one second in a neutral buffer solution with NaCl. The rest potential transient with the laser treatment was measured. In the early stage of the laser treatment the rest potential of zinc alloy-coated steel changed to the negative direction immediately after every irradiation of a laser pulse and then returned to the previous value. However, after the steel substrate was exposed to the solution, the rest potential moved to the positive direction immediately after every irradiation of a laser pulse and then returned to the previous value. The amplitude and duration of the potential change after the laser irradiation increased with repetition of ...
The hydrogen evolution reaction (HER) was studied on bare brass (B), nickel coated brass (B/Ni), nickel-zinc alloy coated brass (B/NiZn, leached Zn), nickel (under layer)/nickel-zinc alloy coated (top layer) brass electrodes (B/Ni/NiZn, leached Zn) in 1 M NaOH solution using electrolysis, cathodic polarization and electrochemical impedance spectroscopy (EIS) techniques. Long term tests were performed in order to evaluate the electrocatalytic activity and corrosion performance of the prepared electrodes with operation time. The results showed that leached electrodes, especially B/Ni/NiZn electrode, have a smaller overpotential than the others and a good electrocatalytic activity for the HER. Its electrocatalytic activity is also stable over electrolysis time. Contrary to the HER performance, B/NiZn cannot provide an adequate corrosion protection. However, when a thin Ni layer was coated under the NiZn ...
Lower cost painting flock-like in appearance and touch feeling was developed as a new surface softening method for automobile interior plastic molded parts. The base coat with the same color as piles mixed into a top coat was first painted on the surface of a plastic molded part after cleaning, and after the top coat with less pitch mixed with piles was painted on the wet base coat and dried by a heater, excess piles were removed with suction and air blowing to produce flock-like appearance. Nylon 66 of 0.4mm in length was used as piles, and mixed into the top coat by 8.0wt% in content. This painting method was applicable to even such parts as one with a complex configuration, and one impossible to set piles on it by conventional methods because of poor durability. As a certain amount of piles with different colors were mixed into the top coat, sprinkly colored ...
Two mechanical design requirements are defined for the SSC Collider beam tube. First, the vacuum requirement (luminosity lifetime = 150 hrs). It requires the design of a pressure boundary within the cold mass vessel to provide a vacuum tunnel for the proton beam and to minimize the synchrotron radiation gas desorbtion with a suitable material. The Collider beam tube design is under an intensive activity to search for a material that will meet the luminosity requirement without a distributed pump or liner. Second is the tube wall`s resistivity requirement ({sigma}*t = 2E5 {Omega}{sup {minus}1}). For a 4.2 K beam tube the Cu thickness is 100 {mu}m (RRR=30,6.7 T, {sigma}=2E9{Omega}{sup {minus}1}m{sup {minus}1}). The copper yield strength is relatively low in comparison to steel and, therefore, the design of the steel layer is governed by the copper layer yield stress limit. A beam tube subjected to eddy current load in a quenching dipole requires an optimum diameter ...
Two mechanical design requirements are defined for the SSC Collider beam tube. First, the vacuum requirement (luminosity lifetime = 150 hrs). It requires the design of a pressure boundary within the cold mass vessel to provide a vacuum tunnel for the proton beam and to minimize the synchrotron radiation gas desorbtion with a suitable material. The Collider beam tube design is under an intensive activity to search for a material that will meet the luminosity requirement without a distributed pump or liner. Second is the tube wall's resistivity requirement ([sigma]*t = 2E5 [Omega][sup [minus]1]). For a 4.2 K beam tube the Cu thickness is 100 [mu]m (RRR=30,6.7 T, [sigma]=2E9[Omega][sup [minus]1]m[sup [minus]1]). The copper yield strength is relatively low in comparison to steel and, therefore, the design of the steel layer is governed by the copper layer yield stress limit. A beam tube subjected to eddy current load in a quenching dipole requires an optimum ...
Researchers are developing polymer-based coating systems to reduce scaling and corrosion of air-cooled condensers that use a geothermal fluid spray for heat transfer augmentation. These coating systems act as barriers to corrosion to protect aluminum fins and steel tubing; they are formulated to resist the strong attachment of scale. Field tests have been done to determine the corrosion and scaling issues related to brine spraying and a promising organometallic polymer has been evaluated in salt spray tests.
The authors describe measurements of emittance made on samples of solar cell coverglasses incorporating new coatings both on C-7940 fused silica and on CMX ceria doped microsheet. Samples of a conventional, MgF_2 coating on the same two types of coverglass substrates were included in the measurements as controls. Measurements were made by the calorimetric method of total hemispherical emittance within a cooled chamber as well as by the more common infrared reflectance method. Emittance enhancements from 1 to 4% were measured for the new coatings.
A zinc/air battery is claimed whose performance is improved by omitting separating elements such as diaphragms etc. The cathode and anode spaces are separated by a collector with holes big enough to permit the electrons to pass freely while restraining the anode material. Further, the active material consists of a spherical care of inert material with a zinc coating. Under the zinc coating, the spherical particles have another thin coating of an electropositive material, e.g. nickel. The cell also contains means for circulating the anode suspension.
Electron paramagnetic resonance was used to investigate surface-coated magnetite-based magnetic fluids doped with TEMPOL. Two magnetic fluid samples, having magnetite nanoparticles with average diameter of 94 A and coated with different coating layers (lauric acid plus ethoxylated polyalcohol in one case and oleoylsarcosine in the other case), were doped with TEMPOL (6 mM and pH 7.4) and investigated as a function of the nanoparticle concentration. The resonance field and the resonance linewidth both scale linearly with the nanoparticle concentration.
On the basis of cylindrical roller thrust bearings it was systematically examined to what extent PVD-coatings are able to take over the function of EP/AW-additives. The bearings were tested under heavy-duty conditions in order to distinguish very fast the efficiency of different coating-substrate-systems. Several coatings were tested for their ability to protect an un-coated counterpart. So just the washers of the roller bearings were coated, the rollers stayed un-coated. Four Me-C:H-coatings showed the best performance and fulfilled the required criterion for roller bearings in the boundary friction: low loss of mass and hardly surface deviation. Material carryover from the carbonaceous coating to the 100Cr6 steel surface was developed by the Me-C:H-coatings during the tests. This mechanism was able ...
A stable BSA blocking poly(dimethylsiloxane) (PDMS) microchannel was prepared based on in situ synthesized PDMS-gold nanoparticles composite films. The modified microchip could successfully suppress protein adsorption. The assembly was followed by contact angle, charge-coupled device (CCD) imaging, electroosmotic flow (EOF) measurements and electrophoretic separation methods. Contact angle measurements revealed the coated surface was hydrophilic, water contact angle for coated chips was 45.2^o compared to a water contact angle for native PDMS chips of 88.5^o. The coated microchips exhibited reproducible and stable EOF behavior. With FITC-labeled myoglobin incubation in the coated channel, no fluorescence was observed with CCD image, and the protein exhibited good electrophoretic effect in ...
Performance and emissions data were gathered on a normally aspirated single cylinder DI engine with various combinations of ceramic coatings installed. Thin ceramic thermal barrier coatings were applied to the piston crown and bowl, the head and valves, and the cylinder liner. The coated piston and head were run singly and in combination with the cylinder liner to investigate the effects of these different coated surfaces on emissions and performance. Coating the piston crown alone results in generally lower cylinder pressure, lower brake specific fuel consumption and lower NO(x) emission compared to the baseline engine. Soot emission is typically increased below 2000 RPM and decreased above 2000 RPM. Coating the head alone reduces cylinder pressure, but generally increases specific fuel consumption and NO(x) and soot emission. The KIVA-II code was used to model ...
Aluminium AA5182 coupons covered by a polyaniline film in the emeraldine base (EB) form showed increasing corrosion potential and decreasing corrosion current as a function of the thickness of the polymer layer. The cathodic reaction was proved not limited by diffusion of species inside the electrolyte solution and oxygen had no effect on the electrochemical behaviour of the coated samples. An EB coating on indium tin oxide conducting layer appeared slightly electroactive in neutral media. The IR spectra of aluminium coated samples, before and after heating in argon atmosphere, confirmed a redox reaction between the polymer film and the metal. This galvanic coupling can explain the good protective behaviour of emeraldine base against corrosion of aluminium.
COATINGS FOR THE METAL-SEMICONDUCTOR SOLAR CELLS 3S GIVEN. THIS METHOD UTILIZES THE MEASURED EQUIVALENT INDEX OF. REFRACTION OBTAINED FROM ELLIPSOMETRY ...
The mechanical stability of diamond-like carbon (DLC) films coated on nitinol vascular stents was investigated under cyclic loading condition by employing a stent crimping system. DLC films were coated on the vascular stent of a three dimensional structure by using a hybrid ion beam system with rotating jig. The cracking or delamination of the DLC coating occurred dominantly near the hinge connecting the V-shaped segments of the stent where the maximum strain was induced by a cyclic loading of contraction and extension. However the failures were significantly suppressed as the amorphous Si (a-Si) buffer layer thickness increased. Interfacial adhesion strength was estimated from the spalled crack size in the DLC coating for various values of the a-Si buffer layer thickness.
The main purpose of solid or fluid lubricants in ball-bearings is to separate the balls and races from contacting each other in so-called asperity collisions. Steel to steel contacts lead to microwelds which roughen functional rolling-contacting surfaces and deteriorate the lubricant. By using balls with a ceramic TiC coating, two goals are achieved. First, there are fewer asperity collisions because of the extreme smoothness of the high precision polished TiC coated balls. Second, if collisions do occur, there is practically no microwelding taking place, leaving the surfaces and the lubricant in good condition. Examples are given where the bearing lifetime is increased up to 10 times if the steel balls are replaced by TiC-coated balls. (orig.).
• Background and Aims The occurrence of stomata in seed coats is uncommon and there is limited information about their function(s). The aim of this study was to verify the distribution...Full Text Available
The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces which are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate triode sputtering methods are discussed. In addition to substrate temperature, the bcc-to-beta phase ratio in sputtered tantalum coatings is shown to be sensitive to other substrate surface effects.
Polymer-coated magnetic nanoparticles (MNPs) have been prepared and used as an immobilization matrix for the fabrication of solid-state tris(2,2prime-bipyridyl)ruthenium(II) (Ru(bpy)32+) electrogenerated chemiluminescence (ECL) sensor. The pre-synthesized maghemite (g-Fe2O3) MNPs were coated with poly(3-thiopheneacetic acid) based on an oxidative polymerization method using KMnO4. The poly(3-thiopheneacetic acid)-coated MNPs have formed the clusters with average diameter of 200-500nm. The multilayer films of poly(3-thiopheneacetic acid)-coated MNPs were uniformly formed on the surface of a Pt electrode by an external magnet. The Ru(bpy)32+ was rapidly incorporated into the multilayer films within 5min through the electrostatic interaction between the Ru(bpy)32+ and the negatively charged c...
Herein, we demonstrate the structure of the PS colloidal crystals which were fabricated on the hydrophilic/hydrophobic Si wafers by a spin-coating technique. Monodisperse PS colloids are spin-coated onto self-assembled monolayers of 3-(aminopropyl)triethoxysilane and propyltrimethoxysilane coated Si wafers. PS spheres organized as ordered close-packed face-centered cubic structure with (111) planes on the hydrophilic surface while they gathered without the crystal structure on the hydrophobic surface. This paper also reports a simple and rapid method to fabricate the close-packed structure of hollow TiO2 spheres. The colloidal crystal of TiO2 hollow spheres was prepared using the PS sphere template on the hydrophobic surface. The mechanism for the growing multilayers of self-assembled PS p...
A test bench was designed and assembled to carry out impact tests on samples and components. The system allows simple and rapid adjustment of the test parameters, such as the shot size and air pressure, with good repeatability of the results. Tests on steel and light alloys were carried out under both as-produced condition and on thin hard-coated samples. Significant reductions in dimple dimensions were seen after coating. FE models simulating the experiments overestimated the dimple depths, although the parameter trend was satisfactorily captured. The residual stresses from coating and shot peening determined numerically are believed to have been proven effective against fatigue.
Ni-Co/SiC nanocomposite coatings were electrodeposited in a modified watt type of Ni-Co bath containing 20nm SiC particles to be codeposited. Potentiodynamic polarization tests were conducted to study the effect of the SiC particulates on the electrodeposition of Ni and Co. Scanning electron microscopy was used to assess the morphology of the Ni-Co alloy and Ni-Co/SiC nanocomposite coatings. The distribution of the particulates in the matrix was considered by means of transmission electron microscopy. Applying nanomechanical testing instruments coupled to atomic force microscopy, mechanical properties of the alloy and composite coatings were studied and compared. The presence of 11vol.% SiC in the Ni-Co matrix increased hardness more than 60%. The average depth of scratch in the mentioned ...
Fluorocarbon polymers are used to enhance thermal stability and electrostatic protection of composite propellant compositions. A precipitation technique has been developed to coat ammonium perchlorate (AP) using a copolymer of hexafluoropropylene and vinylidene fluoride (HFP-VF) with the help of solvent-counter solvent method. The coated AP has been used to prepare propellant compositions in different ratio based on hydroxyl terminated polybutadiene (HTPB), aluminium powder along with uncoated AP and studied for viscosity build-up and visco-elastic behaviour as well as mechanical, ballistic, thermal and sensitivity properties keeping 86% solid loading. The data on viscosity build-up indicate that as the percentage of viton coated AP increases end of mix viscosity and viscosity build-up inc...
TiB{sub 2} appears to be a promising material for the wear protection in various tribological systems, e.g. the diecasting of Al. This study focuses on the development of titanium boride coatings deposited by PACVD, a deposition method which is most suitable for the coating of substrates with complex shapes. All layers analysed are very smooth and exhibit a quasi-amorphous fracture surface. XRD and TEM analysis indicate a nanocrystalline structure with grain sizes in the order of 2 nm. The diffraction patterns can well be correlated to titanium diboride. WDS reveals an over stoichiometric B/Ti ratio. The layer hardness reaches the value of 33 GPa and the critical load in scratch tests rises to 35 N. Neither 100Cr6 nor Al as a counterpart in pin-on-disk tests leads to wear of the coating. (orig.)
Plasma Technologies in Institute of Plasma Physics of the NSC KIPT are recently developed in the following directions. Material surfaces modification under their irradiation with pulsed plasma streams of different working gases. Besides traditional analysis of improvements of tribological characteristics and structural-phase changes of the modified layers recently we started investigations of material corrosions characteristic improvement under influence of pulsed plasma on the material surfaces. As to the surface coatings in arc discharges of Bulat type devices, new trends are related with multi-layers coatings, using Ti-AI-N coatings in cutting tools, using high frequency discharges or combined HF- and arc discharges for increasing the nomenclature of goods to be coated. Development of ozonators is respectively new area for IPP NSC KIPT. On the base of barrier high-frequency discharge there were ...
Amino-rich polymeric coatings are widely used in biomedical applications, since they promote adsorption of diverse biomolecules or facilitate cell growth. As a consequence, there is a growing interest in fabrication of such coatings that is focused predominantly on the optimization of the deposition process in terms of high density of primary amino groups. In addition, the nature of biomedical applications requires also sufficient stability of the films in aqueous environments. This aspect is investigated in this contribution. In particular, the effect of water and phosphate buffer saline on the coatings prepared by RF magnetron sputtering of Nylon 6,6 in Ar/N2 and N2/H2 gas mixtures is evaluated. The samples exposed to liquids are characterized by various diagnostic methods and their prop...
Corrosion behavior of deposition coated specimens prepared by the technique proposed by the authors is investigated in salt immersion tests, and also those of pure magnesium, 3N, 4N and 6N grades, and magnesium alloys, AZ31 and AZ91E, are investigated for comparison. Inhomogeneous corrosion occurs in AZ31 and AZ91E alloys when buffered solutions with pH values of 6.5 and 9.0 including 1% NaCl and a conventional 3% NaCl solution are used for immersion tests, while 6N-Mg shows homogeneous corrosion in such solutions. Corrosion behavior of the deposition coated specimen resembles that of 6N-Mg. Purification process included in the deposition coating technique provides homogeneity in microstructural and electrochemical terms, which results in improving corrosion resistance. (orig.)
In the present study, surfaces of cylinder head, piston, exhaust and inlet valve of a four-stroke, direct injection, single cylinder diesel engine were coated with molybdenum (Mo) by plasma spray method. Thus, thermal barrier characteristic was brought to these parts. Variances in performance and emission values of cotton methyl ester and 2D fuel mixtures were studied in the ceramic coated and uncoated engines under the same running conditions. Performance (6.0% for specific fuel consumption) and emission values (up to 18.0% for CO, 8.0% for smoke density) of the test fuel were improved in the coated engine compared with the uncoated engine. NO_x increase (4.5%) with the increased temperatures expected in the coated engine.
The case of spontaneous radiation of channeled ultrarelativistic particles is considered when the dipolarity condition is not satisfied. The change of the particle longitudinal velocity affecting the maximum radiation frequency is included. The angular and frequency characteristics of the radiation for superhigh energies are studied for the first time. It is shown that there is an optimum energy at which the radiation density is maximum. The influence of the angle at which electrons enter a crystal and of the beam divergence on the radiation is investigated. The problem of quasichanneled particle radiation and also the radiation in axis-plane transitions are considered. (author).
Micron-size Ni-base alloy (NBA) powders were mixed with both 1.5 wt.% (hereinafter %) micron-size CeO{sub 2} (m-CeO{sub 2}) and also 1.5% and 3.0% nano-size CeO{sub 2} (n- CeO{sub 2}) powders. These mixtures were coated on low-carbon steel (Q235) by 2.0 kW CO{sub 2} laser cladding. The effects on the microstructures, phases and electrochemical corrosion of the coatings upon the addition of m- and n- CeO{sub 2} powders to NBA (m- and n- CeO{sub 2} /NBA) have been investigated. The results showed that a smooth coating was prepared under suitable processing parameters (P= 2.0 kW, V= 180 mm min{sup -1}) by adding 1.5% n- CeO{sub 2}. In addition to the primary phases of {gamma}-Ni, Cr{sub 23} C{sub 6} and Ni{sub 3} B in the Ni-base alloy coating, CeNi{sub 3} was formed in Ni-base alloy coatings with both n- CeO{sub 2} and m-CeO{sub 2} particles, and CeNi{sub 5} appeared in the ...
This SBIR Phase I developed neutron detectors made from gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the front surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed from a layer of Al{sub x}Ga{sub 1-x}As. Schottky-barrier diodes formed from the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The ...
Systematics of neutron capture radiative width were studied in the target element range from Th to Cm. Reduced radiative widths were analyzed with a simple radiative width formula based on E1 transition. Average radiative width is presented with the standard deviation of 15%. (author)
Ewing's sarcoma is the most common malignant bone tumour occurring in children and adolescents and exists in two different clinico pathological entities: osseous Ewing's sarcoma (OES) and extraosseous Ewing's sarcoma (EES). Five cases of primary epidural EES are described, which presented with non-specific symptoms leading to a long diagnostic delay. The median age at diagnosis was 22 years (range 13-36 years). The median diagnostic delay was 3 months. All patients had one or more neurological deficits. All underwent surgical exploration with a laminectomy and partial resection followed by adjuvant radiotherapy to a dose of 46-50 Gy and chemotherapy with VAC (vincristine, adriamycin and cyclophosphamide) alternating with ICE (ifosphamide, cisplatin and etoposide) for at least six cycles. The mean follow-up period is 21.2 months (range 11-32 months). Four of the five patients achieved a complete remission and are disease free at the time of writing this report. Two patients have a ...
The reconstruction of segmental defect in long bone is a clinical challenge. Multiple surgeries are typically required to restore the structure and function of the affected defect site. In order to overcome this defect a biodegradable bone tissue engineering scaffold is used. This scaffold acts as a carrier of proteins and growth factors, while also supporting the load that the bone would normally sustain, until the natural bone can regenerate in its place. Work was done to optimize an existing solid free-form scaffold design. The goal of the optimization was to increase the porosity of the scaffold while maintaining the strength of a previously-tested prototype design. With this in mind, eight new designs were created. These designs were drawn using CAD software and then through the use of finite element analysis the theoretical ultimate compressive strength of each design was obtained. Each scaffold design was constructed by casting a thermal-curable ...
The high temperature abrasive wear resistant of the composites with different Al{sub 2}O{sub 3} volume fractions, particle coating and size were investigated and the failure action of composites under different conditions at high temperature was analyzed. The results showed that the high temperature abrasive wear resistant of composite with Ni coating and wide size and 39% volume fraction of particle is the best among all composites examined. (orig.)
PVD-coatings based on TiB{sub 2} are expected to show high wear resistance and low tendency of adhesion on metal forming tools. Coating adhesion and morphology can be modified over a wide range by varying the content of nitrogen (N{sub 2}) and the deposition parameters power and bias voltage. All coatings were deposited using commercial unbalanced magnetron equipment, the deposition was homogeneous in a volume of 400 x 400 x 400 mm{sup 3}. Hipped and hot pressed TiB{sub 2}-targets were used, nitrogen (N{sub 2}) was added as gas, Ti and Al by a solid Ti-Al-target. The tribological behaviour was tested by a pin-on-disc wear test. The coatings investigated were TiB{sub 2}, TiAlB(N), TiAl(N) and TiB{sub 2}/TiAl(N). As counterpart in the pin-on-disc wear test, 6 mm diameter spheres of steel (100Cr6), aluminium, brass and bronze were used. The experiments showed a non-uniform wear behaviour. For the ...
This rebuttal to a previous article provides new insight into the use of sprayed sealants in uranium mines. The author rejects the idea that the value of rock sealant on radon control is destroyed by changes in barometric pressure, showing that this is not necessarily true. The analyses described demonstrate that radon contamination resulting from changing barometric pressures is reduced by a rock coating. The overall use of coatings depends on their costs and effectiveness as compared with other radon control measures. 6 refs.
A super-hydrophobic coating was prepared by combining a rigid base film with crater-like hemispherical holes and acicular nanoparticles. The acicular boehmite powder provides a high contact angle on the film surface. The rigid base film with crater-like hemispherical holes inhibits the rapid decrease of contact angle by surface rubbing. The combination of different roughness is an effective method for improving the abrasion resistance of super-hydrophobic films.
The effectiveness of an acrylic latex wall sealant in limiting the escape of radon from rock in underground mines is the subject of this paper. Application of the latex as a two-coat system over a fillter coat of gunite produced a reduction of radon concentration from an initial level of 80 to 100 pCi/L to a final average of 25 to 30 pCi/L under similar conditions.
Thin solid films of CeO[sub 2] and mixed CeO[sub 2]-TiO[sub 2] were prepared by the sol-gel route via the dip-coating technique. Particulate sols of ceria were made from inorganic ((NH[sub 4])[sub 2]Ce(NO[sub 3])[sub 6]) precursor which were used for preparation of CeO[sub 2] thin solid films while CeO[sub 2]-TiO[sub 2] coatings have been made by using mixed organic-inorganic (Ti(OiPr)[sub 4] and CeCl[sub 3].7H[sub 2]O) precursors. The solar transmission values (T[sub s]) of both coatings are in the range 0.6-0.8 and depend on coating thickness. Cyclic voltammetric (CV) measurements show that the CeO[sub 2]/LiOH system exhibits higher overall electrochemical reversibility when compared to the CeO[sub 2]-TiO[sub 2]/LiOH system. The CeO[sub 2]/LiOH system is also less sensitive with regard to the coating thickness. Coulometric measurements show that CeO[sub 2] exhibits a larger ...
Four subprojects were completed: development and evaluation of die coatings, accelerated die life characterization of die materials, evaluation of fluid flow and solidification modeling programs, selection and characterization of Al-based die casting alloys, and influence of die materials and coatings on die casting quality.
A portable fiber optic detector that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.
This heat exchanger is a critical step in the development of the Externally Fired Combined Cycle power system, a direct-coal combustion power plant (gas turbine). SiC is the only material with the needed resistance to creep, thermal shock, and oxidation; however a protective coating is needed. Ten candidate materials were identified: alumina-based materials, materials stable with SiO, and low expansion materials. An initial screening study should be performed.
Coatings and sensors having both steric and chemical selectivity. Controlled porosity provides the steric selectivity, whereas chemically tailored film properties, using controlled composition or modification by coupling agents, chemical species replacement, or chemical species within pores, provide the chemical selectivity. Single or multiple layers may be provided.
Chromium nitride/Cr coating has been deposited on surface of 316L stainless steel to improve conductivity and corrosion resistance by physical vapor deposition (PVD) technology. Electrochemical behaviors of the chromium nitride/Cr coated 316L stainless steel are investigated in 0.05 M H{sub 2}SO{sub 4}+2 ppm F{sup -} simulating proton exchange membrane fuel cell (PEMFC) environments, and interfacial contact resistance (ICR) are measured before and after potentiostatic polarization at anodic and cathodic operation potentials for PEMFC. The chromium nitride/Cr coated 316L stainless steel exhibits improved corrosion resistance and better stability of passive film either in the simulated anodic or cathodic environment. In comparison to 316L stainless steel with air-formed oxide film, the ICR between the chromium nitride/Cr coated 316L stainless steel and carbon paper is about 30 m{omega} cm{sup 2} that is ...
The dispersion of more than 20 vol pct submicrometer ceramic particles within a metallic matrix and the deposition of such a cermet to form a thick and tough coating presents problems. Most of the coating techniques have failed in attempting to homogeneously disperse very fine and hard particles in large amounts while avoiding their decomposition or reaction with the metal matrix during the deposition process. A simple and efficient method has been developed for producing ceramic-containing composite coatings. It consists in synthesizing cermet-based materials and in depositing them by a rapid solidification process, such as thermal spraying. Boride- and carbide-based materials have been successfully obtained by plasma spraying reactive powders comprising the basic reagents. These materials, with a microstructure of submicrometer ceramic particles dispersed in a metallic matrix, exhibit good wear-resistant properties ...
There has been a growing interest in new laser systems for use at mid-infra-red wavelengths, driven by requirements for a number of diverse applications. Developments in mid-IR coating technology are following three major thrusts. In the first, the potential of ion-assisted process is being exploited and the technology is already becoming well established in the optical coating industry. In the second, the benefits of using gas-phase precursors are being explored, driven by the potential of avoiding the generation of second phase inclusion in the coatings with associated reduction in laser damage threshold. Research is also addressing the use of nanocomposite materials with an engineered microstructure to produce coatings with dielectric properties of choice. This paper presents a review of progress in some of these areas with special emphasis on the comparison of the properties of materials at DF laser ...
This paper introduces a new method to produce nano-composite powder for the preparation of high performance ZnO varistors. ZnO particles were coated with Bi{sub 2}O{sub 3}, Sb{sub 2}O{sub 3}, Co{sub 2}O{sub 3}, Cr{sub 2}O{sub 3} and other additives via liquid nano-coating technique. Then the prepared powder was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravity and differential scanning calorimetry (TG-DSC) and particle size distribution. The results showed that the ZnO composite powder is homogeneously coated and ultrafine. The densification, phase composition and microstructure of ZnO varistors was studied by linear shrinkage, X-ray diffraction (XRD) and SEM, respectively. The preliminary electrical parameters of ZnO varistors showed that the breakdown voltage V {sub b} (1 mA/cm{sup 2}) and nonlinear coefficient {alpha} is 5400 V/cm and 50, respectively, much ...
This paper presents the first results on formation and study of structure and properties of micro- and nanocomposite combined coatings. By means of modeling the deposition processes (deposition conditions, current density-discharge, plasma composition and density, voltage) we formed the three-layer nanocomposite coatings of Ti-Al-N/Ti-N/Al_2O_3. The coating composition, structure and properties were studied using physical and nuclear-physical methods. The Rutherford proton and helium ion backscattering, scanning electron microscopy with microanalysis, grazing incidence X-ray diffraction, as well as nanohardness tests (hardness) were used. Measurements of wear resistance and corrosion resistance in NaCl, HCl and H_2SO_4 solutions were also performed. For testing mechanical properties such characteristics of layered structures as hardness H, elastic modulus E: H"3/E"2 etc. were measured. It is demonstrated that the formed ...
Non-evaporable thin film getters of various compositions have been produced by sputtering. Among about 20 materials which have been studied, the lowest activation temperature (about 180 degree C) has been displayed by a Ti-Zr-V coating obtained from a cathode made of intertwisted elemental wires. In order to optimize the vacuum properties of this film various production parameters, including the substrate temperature during coating, have been varied. The films have been characterized by pumping speed measurement, secondary electron microscopy, and X-ray diffraction. It has been found that the substrate coating temperature affects significantly the activation temperature, the pumping speed and the gas surface capacity. The highest pumping speed values, obtained for substrate coating temperatures of 250 degree C and 300 degree C, are clearly correlated with the increased surface roughness and porosity of ...
Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} ...
The properties of polycrystalline (Ti, Al)N coatings deposited on non-nitrided, classically plasma-nitrided and low pressure plasma-nitrided AISI H11 steel samples were investigated. The plasma deposition and low pressure plasma nitriding were performed in a Z700-LH magnetron sputter ion plating unit, while a separate unit was used for plasma nitriding of specimens at a pressure of several millibars. The (Ti, Al)N coating was deposited onto all the samples using the same equipment as for the plasma deposition and low pressure plasma nitriding. For the characterization of the composite structures, the following methods were used: scratch test, X-ray diffraction analysis, scanning electron microscopy, scanning tunnelling microscopy and microhardness testing. It was found that plasma nitriding prior to coating deposition strongly affects the growth and properties of hard coatings, such as the ...
Intermetallic compound (IMC) growth at the interface between a Sn coating and a Cu substrate with or without a Ni underlayer and its related stress state was evaluated by real-time measurements using the flexure beam method. For the Sn coating without a Ni underlayer, pyramid-shaped IMC grains of Cu6Sn5 grew along the grain boundaries of Sn from the Cu substrate, especially at the triple grain boundary junctions and the IMC grains rapidly increased their volume during the initial 3?days, During this time, the IMC growth rate was 2.3??m3/day and the compressive stress in the Sn coating rapidly developed and became saturated at about ?11?MPa. In contrast, platelet IMC grains of Ni3Sn4 formed at the surface of the Ni underlayer and the IMCs grew at a rate of 1.0??m3/day for the Sn/Ni coating....
Kitchen oils (olive, soybean and butter) are selected for carbon coatings on LiFePO{sub 4}. The surface properties of LiFePO{sub 4} are unknown or vary depending on synthetic methods. The multi-functional groups of fatty acids in the oils can orient properly to cope with the variable surface properties of LiFePO{sub 4}, which can lead to dense carbon coatings. The low price and low toxicity of kitchen oils are other advantages of the coating process. LiFePO{sub 4} (D{sub 50} = 121 nm)combined with the carbon coating enhances the rate capability. Capacities at the 2C rate reach 150 mAh g{sup -1} or higher. The charge retention values of 2.0C/0.2C are between 94.4 and 98.9%. (author)
Chromium containing amorphous hydrogenated carbon films (a-C : H/Cr) have been prepared by simultaneous rf plasma activated chemical vapour deposition of methane and magnetron sputtering of a chromium target. During deposition the substrates were heated (up to 300C) and DC biased (-200 and -600 V) in order to obtain films with high chemical stability. Constant temperature tests were performed at 250C in air with coatings deposited on silicon substrates. The degradation of the coatings was monitored by Raman spectroscopy and reflectance and transmission measurements. The main degradation mechanisms are discussed and the relevant parameters which improve the durability of the coatings are presented. Furthermore, the durability of solar selective, multilayered coatings which were deposited on copper sheets was investigated. Based on accelerated aging tests at different temperature loads in air (at 220C, ...
Objective: To develop a computerized method of internal dose estimation on radiation protection. Methods: Based on MIRD mathematic model of the organs and by means of the programming language of MS Visual Basic 6.0, a computer program of dose estimation in internal radiation was developed for radiation protection. Results: The computerized method of dose estimation for internal radiation was completed. Conclusions: This computerized method is very convenient for internal radiation dose estimation of several aspects. It can also be used in radiation accident. (authors)
German translation of the publication 'The evaluation of risks from radiation' published in 1965 by the International Commission on Radiological Protection. In a survey, genetic and somatic risks from radiation are presented and explained. (HP).
This book gives an overview of the entire field of radiation protection with the subject areas radioactivity, X-rays, UV radiation, laser beams and high-frequency electromagnetic fields. It deals graphically with the most important physical notions, the incidence, origin, properties and biological effects of types of radiation, administrative and practical protection measures and the code of rules governing them. Apart from fundamentals of radiation protection the emphasis on the following: natural radiation exposure, radiation exposure to radon, disaster relief plans in the environment of nuclear plant, the precautionary radiation protection system evolved after Chernobyl, radiation exposure through UV radiation devices, radio, RF communication, radar, microwave ovens and high-voltage transmission ...
The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CN_x coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CN_x was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the surface. In situ x-ray photoelectron spectroscopy was used to evaluate the effect of the plasma treatment on surface chemistry, and electron microscopy was used to identify changes in the surface morphology of the PMC ...
CeO{sub 2}-coated LiMn{sub 2}O{sub 4} spinel cathode was synthesized using two-step synthesis method. All the samples exhibited a pure cubic spinel structure without any impurities in the XRD patterns. The results of the electrochemical performances on CeO{sub 2}-coated electrode are compared to those of electrodes based on LiMn{sub 2}O{sub 4} spinel without CeO{sub 2} coating. CeO{sub 2}-coated LiMn{sub 2}O{sub 4} cathode improved the cycling stability of the electrode. The capacity retention of 2 wt% CeO{sub 2}-coated LiMn{sub 2}O{sub 4} was more than 82% after 150 cycles between 3.0 and 4.4 V at room temperature and 82% after 40 cycles at elevated temperature of 60 C. The amounts of dissolved manganese-ions in CeO{sub 2}-coated LiMn{sub 2}O{sub 4} significantly are smaller than pristine LiMn{sub 2}O{sub 4} systems especially at elevated temperatures. ...
We have investigated the growth behaviors of high temperature compatible ZrO_2 insulation coatings on Ag and AgMg sheathed Bi_2Sr_2Ca_1Cu_2O_x superconducting tapes depending on number of dipping and thermal conditions. The coatings were fabricated on long-length superconducting tape substrates using a solution derived from Zr tetrabutoxide, solvent and chelating agent for high magnetic field magnets. The layer-on-layer growth behaviors were characterized by environmental scanning electron microscope (ESEM), energy dispersive spectroscopy (EDS), X-ray maps and X-ray diffraction (XRD). This research showed that the ZrO_2 coatings were regularly grown on Ag-based tape substrates and coating thickness increased with increasing number of dipping. It was found that ceramic oxides formed at temperature range 450 and 550 deg. C. The final coating thickness changed between 6 and 8 #mu#m ...
The possibilities to electrodeposit thick coatings composed of nanoparticles of Sb and Sb{sub 2}O{sub 3} for use as high-capacity anode materials in Li-ion batteries have been investigated. It is demonstrated that the stability of the coatings depends on their Sb{sub 2}O{sub 3} concentrations as well as microstructure. The electrodeposition reactions in electrolytes with different pH and buffer capacities were studied using chronopotentiometry and electrochemical quartz crystal microbalance measurements. The obtained deposits, which were characterised with XRD and SEM, were also tested as anode materials in Li-ion batteries. The influence of the pH and buffer capacity of the deposition solution on the composition and particle size of the deposits were studied and it is concluded that depositions from a poorly buffered solution of antimony-tartrate give rise to good anode materials due to the inclusion of precipitated Sb{sub 2}O{sub 3} ...
As surface treated steel sheets, steel sheets with Zn-Fe coatings as well as double-layer steel sheets with Fe-P alloy coatings on Zn-Fe alloy coatings are often used practically. Two treatment methods, which are used to dissolve only alloy layers without dissolving steel sheets in order to find amount and composition of alloy layersr have already been reported. This report investigates the mechanisms of these methods, particularly the mechanisms to control dissolution of steel sheets. In the alkali-dissolution method, Zn-Fe alloy coatings are dissolved in a strong alkaline solution(NaOH-triethanolamine (TEA)-H{sub 2}O{sub 2}). In this case, steel sheets are insoluble because passive films are formed on the surface. In the cathodic polarization electrolysis method, alloy layers are electrolyzed({minus}l.2V) and dissolved in an ammonium nitrate-0-phen electrolyte. At this potential, dissolution of steel ...
Silica microspheres were deposited into two-dimensional periodic arrays and coated with a thin layer of silicon nanocrystals. The luminescence from the silicon nanocrystals coupled into the whispering gallery modes of the spheres, with Q factors that depended on a range of parameters including sphere size, position on the sphere, viewing direction, and thickness of the nanocrystal coating. Scattering from the film-sphere and/or the sphere-substrate contacts resulted in a lower Q for modes that intersect these regions. The highest Q factors obtained in this work were {approx}1500. The results suggest that silica microspheres may be promising candidates for high-Q cavities that incorporate silicon nanocrystals for cavity QED or nonlinear optical effects.
In this study, the effects of channel surface wettability, cross-sectional geometry and orientation on the two-phase flow in parallel gas channels of proton exchange membrane fuel cells (PEMFCs) are investigated. Ex situ experiments were conducted in flow channels with three different surface wettability (hydrophilically coated, uncoated, and hydrophobically coated), three cross-sectional geometries (rectangular, sinusoidal and trapezoidal), and two orientations (vertical and horizontal). Flow pattern map, individual channel flow variation due to maldistribution, pressure drop and flow visualization images were used to analyze the two-phase flow characteristics. It is found that hydrophilically coated gas channels are advantageous over uncoated or slightly hydrophobic channels regarding un...
Steel structures immersed in seawater are protected from corrosion using cathodic protection systems (sacrificial anodes or impressed current), by paint coatings or by duplex systems in which cathodic protection hinders corrosion at coating's failure sites. The main problem related to those duplex systems is how to avoid cathodic delamination due to the alkalinity generated at cathodic sites. The present paper analyses the effectiveness of red mud suspensions as pre-treatment to avoid cathodic delamination. The study was conducted using mainly electrochemical impedance spectroscopy (EIS). The evolution of the electrode potential with immersion time was also recorded because it concerns the practical aspect of current density necessary to reach the protection potential. The study shows that red mud pre-treatments are effective in avoiding coating's delamination. (author)
In order to improve the well-known short operational life time of BF3 counters, three potential adsorbents for impurity gases (graphite, activated charcoal and a zirconium-aluminum mixture) were introduced into BF3 counters in the form of coating on the aluminum cathode surface. Tests in el fields revealed that a partial coating of activated charcoal provides the best result. The improvement of their operational life in el fields was about three orders of magnitude in terms of tolerable exposure. Many counters with a partial coating of activated charcoal were further tested from the following viewpoints: background noise, vibration and shock, el pulse discrimination, operational life in a neutron field and non-operational in-reactor exposure life. The results were satisfactory for reactor control and protection usage. (author).
Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.
The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the #beta#-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P_2O_5-7Na_2O-3TiO_2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P_2O_5-7Na_2O-3TiO_2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)
Apparatus for solid-phase antibody separation techniques used in radioimmunoassays is described in this invention. It consists of a rectangular prism tray with multiple wells protruding into its interior from one side. Near the base of the tray is an orifice used for creating evacuated condition within the structure. At the base of each well there is an orifice of such size and shape as to retain an aqueous liquid under given pressure conditions but permit the evacuation of this liquid at reduced pressure. The outlet of these orifices is in the shape of an inverted conical frustrum. Each of the wells contains an antibody coated disc of porous cellulose paper surrounded by a plastic support. The porous nature of the cellulose paper ensures contact between the antibody coating and the antigen. The use of antibody coated porous cellulose paper in combination with the vacuum operated apparatus simplifies the manipulative steps ...
Kawasaki Steel has constructed many facilities for 15 years to produce cold rolled products and galvanized products in Mizushima Works and Chiba Works. To efficiently and stably produce high and uniform quality products, various new control methods have been developed and applied to these new facilities. Especially, temperature control in a continuous annealing line, zinc coating control in a continuous galvanizing line or paint coating control in a multi-purpose coating line and tension control to achieve stable processing are the most advanced technologies and are introduced in this paper. (author)
In this study, a novel graphene nanosheets (GNSs) coated solid phase microextraction (SPME) fiber was prepared by immobilizing microwave synthesized GNSs on a stainless steel wire. Microwave synthesized GNSs were verified by X-ray diffraction, field emission-scanning electron microscopy (FE-SEM) and transmission electron microscope (TEM). GNS-SPME fiber was characterized using FE-SEM and the results showed the GNS coating was homogeneous, porous, and highly adherent to the surface of the stainless steel fiber. The performance and feasibility of the GNS-SPME fiber was evaluated under one-step microwave assisted (MA) headspace (HS) SPME followed by gas chromatography with electron capture detection for five organochlorine pesticides (OCPs) in aqueous samples. Parameters influencing the extra...
Sesame varieties/genotypes showed a good response to radiation with gamma rays and treatments with EMS. In M_1 both gamma rays and EMS influenced germination, seedling height, survival of plants and pollen fertility/sterility, producing deleterious effects on these characters. Compared to black seeded genotypes, white seeded ones are more susceptible to radiation. Both gamma rays and EMS produced various types of morphological variations in M_2 generation. These were dwarf plant mutants, mottled and fleshy leaved mutants (sterile), fasciated stem, flower colour, altered phyllotaxy, early, uniculm, capsule size variations, multiple capsule/leaf axil, seed coat colour variations, indehiscent and semi-indehiscent type mutants. Moreover, studies on quantitative characters including seed yield revealed the induction of mutants in both positive and negative directions for such traits which made a good scope of selection of ...
Subject to the provisions of the Radiation Protection Act, the Authority, on the advice of ...(f) in collaboration with the Radiation Protection Board, conduct an ionising radiation monitoring programme and ...or document kept under the control of the Radiation Protection Board.
Described and discussed in this paper are radiation processes and their advantages over the conventional techniques. Radiation sterilization of medical products, food irradiation, wood plastic composites, and radiation treatment of sewage and waste waters are presented. The Philippine experience in using these technologies, its problems and barriers are also given. (ELC).
This text-book (electronic book - multi-media CD-ROM) constitutes a course-book - author's collection of lectures. It consists of 13 lectures in which the reader acquaints with the basis of radiobiology: Introduction to radiobiology; Physical fundamentals of radiobiology; Radiation of cells; Modification of radiation damage of cells; Reparation of radiation damage of cells; Radiation syndromes and their modification; Radiation injury; Radiation damage of tissues; Effect of radiation on embryo and fetus; Biological effects of incorporated radionuclides; Therapy of acute irradiation sickness; Delayed consequences of irradiation; Radiation oncology and radiotherapy. This course-book may be interesting for students, post-graduate students of chemistry, biology, physics, medicine as well as for teachers, scientific workers ...
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This chapter is concerned with standards and guidances for limiting radiation exposures. It is divided into three sections, each of which has several parts. Section 1: Ionizing Radiation -- Standards and Guidances Applicable to the Public: Part A, Radiation Protection Standards; Part B, Environmental Radiation Standards; Part C, Exempt Levels of Radioactivity; Part D, Protective Action Guides for Accidents. Section 2: Ionizing Radiation -- Standards Applicable to the Workplace. Section 3: Medical and Other Standards.
On the basis of legally provided area dose measurements and time records of fluoroscopic examinations during the operation, radiation doses to medical personnel and patients are evaluated. Adequate radiation protection measures and a careful behaviour in the operating room keep the radiation exposure to the personnel below the maximum permissible exposure. Taking into account the continuous personnel radiation monitoring and medical supervision, radiation hazards in the operating room can be considered low.
Oct 20, 1997 ... The following requirements apply to the solar array: ..... housings will be coated with material meeting the program's outgassing requirements. ... The solar array temperature testing requirements will be determined by analysis. .... The ADS also generates attitude products for the project and science team. ...
Synthetic oligoribonucleotides have been used to probe the interaction of MS2 coat protein with the translational operator of the MS2 replicase gene. We have investigated the possible formation of a...Full Text Available
In the present paper the tribological behavior of the coatings are discussed. Duplex coatings were applied on cold working steel 100Cr6. Samples were plasma nitrided at different thickness of plasma surface layers. TiN was deposited with a classic BALZERS PVD equipment and subsequent ion implantation. Ion implantation was provided with N{sup 5+} ions. The other samples were produced with IBAD technology in DANFYSIK chamber. Wear resistance and exchanges of friction coefficient were measured with on-line test using special designed tribology equipment. Following the tests, the wear zone morphology and characteristics of surface layer structure as well as important properties were investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Scratch adhesion testing was performed using commercially available equipment. Energy dispersive X-ray analysis (EDAX) of the wear-scars on pins provided essential information on ...
Amperostatic coulometry was applied for the thickness measurement of Sn-Ag hot dip coatings, which comprise an extended Sn-Cu interdiffusion layer. Complementary measurements, notably weight loss, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray fluorescence (XRF), and dynamic secondary ion mass spectroscopy were performed in order to obtain a better interpretation of the coulometry results. Based on the experimental results presented in this article, the three potential changes observed during coulometry measurements are ascribed to (i) the entire dissolution of pure Sn, (ii) the formation of a CuCl salt layer, and (iii) the surface passivation. The measurement of the pure Sn mass is well reproducible despite strong coating thickness variations detected by XRF. Several experimental problems, in particular, a coating undercutting, hamper the determination of the Sn mass in the intermetallic ...
We tried to apply a quartz crystal as a sensor by using the resonant frequency and the resistance properties of quartz crystals. Four kinds of fatty acids that have the same head groups were coated on the surfaces of the quartz crystals, and the shift of the resonant frequency and the resistance were observed based on the lengths of the tail groups. Myristic acid (C{sub 14}), palmitic acid (C{sub 16}), stearic acid (C{sub 18}), and arachidic acid (C{sub 20}) were deposited on the surfaces of quartz crystals by using the Langmuir-Blodgett (LB) method. As a result, the resonant frequency change was more sensitive to high molecular-weight fatty acids than to low molecular-weight ones. We also observed the effect of temperature on stearic acid LB films, and the response properties of quartz crystals coated with stearic-acid LB films to organic gases were investigated. As a result, the sensitivity of quartz crystals to organic gases was higher for ...
This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope ...
In recent years, the interest in the use of bacteria for biological control of plant-pathogenic fungi has increased. We studied the possible side effects of coating barley seeds with the antagonistic...Full Text Available
Background.The air bubbles and foam that develop during the preparation of platelet units have traditionally been considered to interact with the platelets, causing activation and...Full Text Available
An immunoassay employing 125I-labeled enterotoxin B and polystyrene tubes coated with specific antibody was used for assaying purified and crude enterotoxin. Antibody was adsorbed to untreated...Full Text Available
An antigen-antibody system of polystyrene tubes coated with immunoglobulin antibody was used for quantitating immunoglobulins. A similar radioimmunoassay method was adapted for a viral antigen-antibody...Full Text Available
Enzymes are versatile catalysts in laboratories and on an industrial scale; improving their immobilization would be beneficial to broadening their applicability and ensuring their (re)use. Lipid-coated...Full Text Available
This work analyzes the unoptimized prototype triode-sputtered, 150 microns thick tantalum coatings deposited with a 2.5 microns niobium underlayer on the bore of a large-diameter A723 steel cylinder. The coating was deposited for wear and erosion protection by Pacific Northwest National Laboratory. The phase determination was based on X ray diffraction analysis, wavelength dispersive X ray fluorescence analysis, energy dispersive X ray analysis, and hardness and electrical resistivity measurements. Both X ray diffraction and radius-of- curvature methods were used to determine residual stresses. A locally developed high-resolution pole figure technique was used to perform texture analysis. The post-firing, debonded coating showed alpha-tantalum, preferred 110 orientation, high surface stresses, tantalum oxides, entrapped krypton sputtering gas, interstitial oxygen, and other impurities. The surface and subsurface pole ...
A major problem in the maintenance and rehabilitation of pipelines is the removal of the original coating system, particularly in cases where the coating contains sticky components or adhesives. It has been found that such coatings can be removed by use of a cleaning machine with a plurality of counter-rotating carbide-tipped tools mounted to an oscillating head embracing the pipe, and which is operable at the same time to travel along the length of the pipe. Such a machine can be designed to effect a positive, gentle milling operation on the pipe surface to remove the coating efficiently and at relatively low power consumption. A particular advantage of the pipe cleaning machine of the invention is that its design and manner of operation allows it to be used in the field to clean an uncovered section of pipeline, for example a natural gas pipeline, without the requirement of removing the pipeline ...
As a result of health and safety issues surrounding the use of radioactive materials on coated optical components, there has been renewed interest in coating materials whose optical and mechanical properties approach those offered by their radioactive counterparts. Due to the radioactive nature of ThF{sub 4} and its widespread use in optical coatings, the coating industry is examining other low index and non-radioactive fluorides as possible alternatives. In this paper, the authors present the results of an experimental study on the optical and mechanical properties of thermally evaporated ThF{sub 4}, DyF{sub 3}, CeF{sub 3}, LiF, HfF{sub 4}, IRX, and IRB thin films, where the materials were deposited at different substrate temperatures. The objective is to examine this series of fluorides under comparable deposition conditions and with respect to such material properties as: n and k, film stress, and ...
Progress is reported in fabrication and coating activities being conducted for the weapons program, nuclear test program, nuclear design program, magnetic fusion program, and miscellaneous applications. (DLC)
A latex agglutination (LA) test was evaluated for the detection of human rotaviruses in stool specimens. Both antiserum and immunoglobulin G (IgG)-sensitized latex particles were used, with IgG-coated...Full Text Available
In this paper, we present experimentally determined reflection factors of mirrors based on the depleted uranium and dependence of reflection factor on time of presence of samples on air.
The display of proteins such as feed enzymes at the surface of bacterial spore systems has a great potential use for animal feed. Feed enzymes increase the digestibility of nutrients, leading to greater...Full Text Available
Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP"S"M particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP"S"M particles with a gamma dose equivalent to ...
In support of a new clinical trial designed to compare the effects of crushed fresh garlic and two types of garlic supplement tablets (enteric-coated dried fresh garlic and dried aged garlic...Full Text Available
A solid-phase radioimmunoassay employing 125I-labeled enterotoxins and polystyrene tubes coated with specific antibody has been developed for assaying the relative concentrations of antibodies...Full Text Available
This paper reports that the co-deposition of chromium and silicon into a 2.25Cr-1.0Mo-0.15C steel, alloy 800, and type 304 stainless steel has been achieved using the pack cementation process. The ferritic coating produced on the 2.25 Cr-1.0Mo steel was approximately 225 {mu}m (9 mils) thick, whereas the inward diffusion of chromium and silicon produced a two-phase structure of ferrite and austenite for type 304. Chromium and silicon were incorporated into the austenitic solid solution upon diffusion into alloy 800. All coatings had approximately 25 to 35 wt% Cr and 2 to 3% Si at the surface. Cyclic oxidation testing in air of the coated 2.25Cr-1.0Mo steel (T = 700{degrees} C) and type 304 (T = 1035{degrees} C) showed a dramatic decrease in the oxidation kinetics compared to the original uncoated alloys. The cyclic oxidation of alloy 800 was also improved.
Effects of dopant and coating carbon nanotube on anodic performance of Si were studied for metallic anode Li ion rechargeable battery with large capacity. Although the large Li intercalation capacity higher than 1500mAhg{sup -1} is exhibited on pure Si, it decreased drastically with increasing cycle number. Increasing the electrical conductivity by doping Cr or B is effective for increasing the initial capacity and the cycle stability of Si for Li intercalation. Coating semiconductive Si with the carbon nanotube by decomposition of hydrocarbon is effective for increasing the cycle stability, though the initial Li intercalation capacity slightly decreased. Conducting binder is also important for increasing the cycle stability and it was found that Li intercalation capacity higher than 1500mAhg{sup -1} can be sustained by using poly vinyliden fruolide. Consequently, reversible Li intercalation capacity of 1500mAhg{sup -1} was successfully ...
To maximize energy efficiency, gas turbine engines used in airplanes and for power generation operate at very high temperatures, even above the melting point of the metal alloys from which they are...Full Text Available
Strippable or temporary coatings are innovative technologies for decontamination that effectively reduce loose contamination at low cost. These coatings have become a viable option during the deactivation and decommissioning of both US Department of Energy (DOE) and commercial nuclear facilities to remove or fix loose contamination on both vertical and horizontal surfaces. The ALARA{trademark} 1146 strippable coating was demonstrated as part of the Savannah River Site LSDDP and successfully removed transferable (surface) contamination from multiple surfaces (metal and concrete) with an average decontamination factor for alpha contamination of 6.68 and an average percentage of alpha contamination removed of 85.0%. Beta contamination removed was an average DF of 5.55 and an average percentage removed of 82.0%. This paper is an Innovative Technology Summary Report designed to provide potential users with the information they ...
Extra-fine powdered activated charcoal has been used as stationary phase (coating layer) in solid-phase microextraction (SPME). The efficiency and reliability of the prepared device have been investigated for the extraction of some volatile organic compounds such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) from the headspace of water samples. Monitoring of the extracted compounds and further quantitative analysis of the real samples have been performed by capillary GC-FID. Effects of several factors such as temperature, addition of salt, and stirring speed on extraction efficiency and exposure time have been studied. Under optimum conditions, extraction recoveries for these compounds from 50 mL water were >95%. The calibration graphs were linear in the range 5 to 10{sup 4} pg mL{sup -1} and the detection limit for each BTEX compound was 1.5-2 pg mL{sup -1}. The results obtained by use of this porous layer activated charcoal ...
DNA antoantibodies in serum will bind to antigen-coated polystyrene tubes and can be detected by radiolabelled anti-immunoglobulin. The method is quantitative, gives information on the antibody class...Full Text Available
Deposition of hard coatings may influence the mechanical properties of the bulk material and its corrosion resistance. In this work we study the hardness of the coated and the back side of 100Cr6 steel plates. Electrochemical corrosion tests were performed in O{sub 2}-saturated acetate buffer of pH 5.6 at 25degC. Chromium nitride and titanium nitride coatings prepared by different physical vapour deposition processes, such as arc, thermionic arc evaporation, magnetron sputtering and ion-beam-assisted deposition (IBAD) were compared. The results show that, for sufficient corrosion protection, chromium nitride layers have to be thicker than 500 nm. An increased nitrogen partial pressure in the evaporation chamber of the IBAD process improves the corrosion resistance significantly. The hardness of the substrates was reduced in the case of thermoionic arc evaporation only, indicating a deposition temperature of more than ...
Certain applications are described of radionuclide X-ray fluorescence analysis in the ore dressing industry, in the manufacture of building materials, in metallurgy, pharmacy, in the chemical, photographic and paper industries, in space exploration, in archeology and for measuring the thicknesses of thin layers of coatings. (ES).
The aim of the paper is to review the role of interventional radiology in the management of hemodialysis vascular access and complications in renal transplantation. The evaluation of patients with hemodialysis vascular access is complex. It includes the radiology/ultrasound (US) evaluation of the peripheral veins of the upper extremities with venous mapping and the evaluation of the central vein prior to the access placement and radiological detection and treatment of the stenosis and thrombosis in misfunctional dialysis fistulas. Preoperative screening enables the identification of a suitable vessel to create a hemodynamically-sound dialysis fistula. Clinical and radiological detection of the hemodynamically significant stenosis or occlusion demands fistulography and endovascular treatment. Endovascular prophylactic dilatation of stenosis greater than 50% with associated clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. The technical success ...
The current state and need for radiation protection training in Finland have been surveyed by the Radiation and Nuclear Safety Authority STUK. The survey sought to determine whether the current requirements for radiation protection training had been met, and to promote radiation protection training. Details of the scope and quality of present radiation protection training were requested from all educational institutes and organizations providing radiation protection training. The survey covered both basic and further training, special training of radiation safety officers, and supplementary training. The questionnaire was sent to 77 educational organization units, 66 per cent of which responded. Radiation workers and radiation safety officers were asked about radiation protection ...
Laser surface alloying with gaseous nitrogen was utilized to improve the wear resistance of a Ti-6Al-4V alloy. Wear-resistant composite coatings reinforced by hard TiN dendrites were produced 'in-situ' on a substrate of a Ti-6Al-4V alloy. The hardness and wear resistance of the laser alloyed coating under two-body abrasive and block-on-ring full-sliding wear conditions were significantly enhanced. (orig.)
A series of ball-on-disc wear and friction measurements were made for surfaces which have a chemical vapour deposition carbon silicon alloy layer on a carbon substrate (fine grain POCO graphite). Nitrogen ion irradiation was used to improve the wear resistance of the carbon alloy surface. For comparison, measurements were also taken for alumina against alumina. It was found that the lowest friction coefficient and lowest wear occurred for ion irradiated coated samples containing 4% Si in the alloy and that the performance was superior to that of alumina. ((orig.))
A series of ball-on-disc wear and friction measurements were made for surfaces which have a chemical vapour deposition carbon silicon alloy layer on a carbon substrate (fine grain POCO graphite). Nitrogen ion irradiation was used to improve the wear resistance of the carbon alloy surface. For comparison, measurements were also taken for alumina against alumina. It was found that the lowest friction coefficient and lowest wear occurred for ion irradiated coated samples containing 4% Si in the alloy and that the performance was superior to that of alumina. ((orig.)).
In fluid bed processing in the chemical, food or pharmaceutical industries, pneumatic nozzles are typically used to convert binder or coating liquids into droplets. Producing fine droplets from liquids in a gas phase is termed atomisation, and it involves complex phenomena which are not yet fully understood. This paper provides a systematic and up-to-date review of two-fluid nozzle designs and principles together with a presentation of nozzle fundamentals introducing basic nozzle theory and thermodynamics. Correlations for the prediction of mean droplet diameters are reviewed, compared and accompanied by a discussion of their use.
The performance of a thermophotovoltaic (TPV) converter for solar energy is compared with that of direct solar energy conversion by silicon and germanium solar cells. The optical selectivity of an intermediate emitter is computed. Experimental results on selective emission, based on selectively emitting materials and on antireflection coatings on metals, are reported. For a TPV converter equipped with silicon solar cells, no selective emitter is found to yield better results than would be obtained by direct conversion. A TPV converter with germanium cells operating with a ThO/sub 2/-coated tungsten emitter, however, may achieve a conversion efficiency superior to that of direct solar energy conversion by either silicon or germanium solar cells.
The bibliography contains citations concerning plasma immersion ion implantation (PIII) and equipment. PIII is a new technique to implant plasma ions into materials for surface modification and treatment. Topics include plasma nitriding, semiconductor doping, ion energy distribution, ion dose, pulsed plasma, metal plasma, and defect passivation. References also review applications in semiconductor device and integrated circuit manufacture, silicon material fabrication, aerospace bearings, carbon coatings on metals, and ceramic coatings. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
In this paper, an environmentally friendly metal corrosion inhibitor, phytic acid, was assembled into the walls of silica nanoparticles via layer-by-layer self-assembly technique (LbL) with poly(allylamine hydrochloride). Such functionalized nanoparticles were uniformly distributed into sol-gel films for metal anticorrosion. The films showed very pronounced and lasting protective efficiency in concentrated salt aqueous solutions as indicated by electrochemical impedance spectroscopy (EIS) measurement. These results may provide a new route for the preparation of environment-friendly anticorrosion coatings.
In the early 1970s Yang and Menichelli demonstrated that direct laser illumination of low-density secondary explosive prr:ssings through a transparent window could produce detonation. 'The energy requirement for threshold initiation of detonation was reduced when a thin metal coating of metal covered the side of the window against which the low-density explosive was pressed. We have obtained experimental results that are in general agreement with the results of Renllund, Stanton and Trott (1 989) and recent: work by Nagayama, hou and Nakahara (2001). We report exploration of the effects of laser beam diameter, PEiTN density and specific surface area, and thickness of a titanium coating on the window.
In this study samples of AISI 4140 steel were pretreated by plasma nitriding and coated with two different physical vapour deposited coatings (TiN and TiAlN). A hardened AISI 4140 sample and a coated sample were also included in the investigation. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, two different nitriding conditions - a conventional 25% N{sub 2} and an N{sub 2}-poor gas mixture - were used. The specimens were investigated with respect to their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests in which the duplex-treated pins were mated to hardened ball bearing steel discs were performed in a pin-on-disc machine under dry sliding conditions. Metallography, scanning electron microscopy and profilometry were used to analyse the worn surfaces in order to determine the dominant friction and wear ...
The interdiffusion behaviour of MCrAlY-coats on polycrystalline and single-crystalline materials of a similar composition (IN 738 LC/SC 16)shows similar interdiffusion characteristics. TCF-tests, where stress is generated by temperature and sample geometry at the edges of a disk-shaped sample, show that it is possible to differentiate betwee crack resistance of coated and uncoated samples. This method is also suitable for screening tests with different coat thicknesses. Coating of the edge area must, however, be done with great diligence in order to prevent coat thickness variation as results would then not be reproducable. Contrary to TCF (thermal cycle fatigue) TMF-tests (thermal mechanical fatigue)allow to set the stress states that one wishes to test. This method is therefore well suited for testing under operating conditions.(orig.) [German] Im Rahmen dieser Arbeit wurde ...
In support of the efforts to apply ceramics in advanced heat engines, a study was made of the sliding performance of ceramics at the ring/cylinder interface of low heat rejection engines. The objective was to understand the basic mechanisms controlling the wear of candidate ceramics and thereby identify means for applying these ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and several plasma-sprayed ceramic coatings without lubrication were unsuccessful because of high friction and high wear rates. Experiments using a polyalphaolefin lubricant at temperatures to 260 C identified several combinations having wear rates in the general range likely to be acceptable for engines. Plasma-sprayed coatings of chromium oxide and hypersonic powder flame sprayed coatings of cobalt-bonded tungsten carbide performed particularly well as ring coatings. Similar ...
After being pre-plated a zinc layer, an amorphous Al-Mn alloy coating was applied onto the surface of AZ31B magnesium alloy with a bath of molten salts. Then the corrosion performance of the coated magnesium alloy was examined in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the single Zn layer was active in the test solution with a high corrosion rate while the Al-Mn alloy coating could effectively protect AZ31B magnesium alloy from corrosion in the solution. The high corrosion resistance of Al-Mn alloy coating was ascribed to an intact and stable passive film formed on the coating. The performances of the passive film on Al-Mn alloy were further investigated by Mott-Schottky curve and X-ray photoelectron spectroscopy (XPS) analysis. It was confirmed that the passive film exhibited n-type semiconducting ...
Wear-resistant TiN coatings deposited on tool steels are used frequently in industry. There is a trend towards further optimizing these coatings, e.g. by plasma nitriding the tool surface prior to TiN deposition. In this work the influence of the nitriding conditions on the surface properties of AISI 304 and ASP 23 tool steels was investigated. The plasma nitriding was carried out in a triode ion plating configuration normally used to deposit TiN coatings. At the surface of AISI 304 stainless steel, only a thin compound layer (Fe{sub 4}N, Fe{sub 3}N) was found, probably as a consequence of the rather slow nitrogen diffusion in the austenite matrix. For ASP 23 high speed steel, the different nitriding behaviour of the martensitic matrix causes the formation of a diffusion layer which results in an increase in hardness at the surface. On an analogous set of specimens the TiN deposition was started immediately after the plasma ...
Natural bone consists of hard nanostructured hydroxyapatite (HA) in a nanostructured protein-based soft hydrogel template (ie, mostly collagen). For this reason, nanostructured HA has been an intriguing coating material on traditionally used titanium for improving orthopedic applications. In addition, helical rosette nanotubes (HRNs), newly developed materials which form through the self-assembly process of DNA base pair building blocks in body solutions, are soft nanotubes with a helical architecture that mimics natural collagen. Thus, the objective of this in vitro study was for the first time to combine the promising attributes of HRNs and nanocrystalline HA on titanium and assess osteoblast (bone-forming cell) functions. Different sizes of nanocrystalline HA were synthesized in this study through a wet chemical precipitation process following either hydrothermal treatment or sintering. Transmission electron microscopy images showed that HRNs aligned with ...
The assumed linear relationship between exposure to radiation and cancer incidence is questioned in this article. The current research data on radiation effects at the cellular level is reviewed, as are epidemiological studies of background radiation effects and health effects of populations exposed to low levels of radiation exposure via employment or medical treatments. Statistics reveal that threshold levels currently in force need to be reviewed. Some evidence of beneficial effects of low level radiation exposure effects of low level radiation exposure is also presented, and so regulations should be reviewed at an international level. (UK).
The most propagated mechanisms of stimulated radiation of electron beam such as Cherenkov one-particle and collective effects, ondulator and magnetic bremsshrahlung radiations, Doppler anomalous effect, Thompson and Raman scattering and radiation are discussed. Relation of spontaneous radiation mechanisms of individual electron and stimulated radiation effects in electron beams has been elucidated, grounds of linear electrodynamics of radiative beam instabilities are stated, and main mechanisms of their nonlinear stabilization are elucidated as well. Various simulated processes in electron beams are considered from the unique point of view using a simple mathematical apparatus and such physical laws as conservation and Newton laws.
This manual was written for individuals who wish to become qualified in radiation protection as an adjunct to working with sources of ionizing radiation or using radionuclides in the field of medicine. It provides the radiation user with information needed to protect himself and others and to understand and comply with governmental and institutional regulations regarding the use of radionuclides and radiation machines. It is designed for a wide spectrum of users, including physicians, research scientists, engineers, and technicians. It should be useful also to radiation safety officers, members of radiation safety committees, and others who are responsible for the proper use of radiation sources, although they may not be working with the sources directly. The presentation in this manual is designed to obviate the need for reviews of atomic ...
Abstract Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system of - 21 Wm-2. The short wave radiative effect of cloud is primarily manifest as a reduction in the solar radiation absorbed at the surface of - 53 Wm-2. Clouds impact long wave radiation by heating the moist tropical atmosphere (up to around 40 Wm-2 for global annual means) while enhancing the radiative cooling of the atmosphere over other regions, in particular higher latitudes and sub-trop...
The book examines current experimental and clinical knowledge concerning the biological and biophysical effects of electromagnetic radiation, particularly that in the microwave range. The biophysical bases of the interaction of electromagnetic radiation with matter are reviewed with emphasis on biological systems, and the effects of radiation on critical biological systems, including the nervous, reproductive, visual and blood-forming systems are compared. Data concerning the lethal effects of nonionizing radiation is presented and characteristics of the effects of electromagnetic radiation on the whole mammalian organisms are examined. Various reactions of the neuroendocrine system to electromagnetic radiation are described, with particular attention given to the adrenal system, and the combined effects of ionizing and microwave radiation ...
The main compositions of iron-base amorphous self-fluxing alloy powders of 150 mesh, used in this work, are Fe, Cr, Ni, W, Mo, B, Si and C. The ranges of each element in at% are (65-70)Fe, (3-5)Cr, (2-4)Ni, (2-4)W, (1-2)Mo, (10-14)B, (4-7)Si and (2-3)C. The atomic ratio of metal-metalloid is about 80:20, so this alloy is abbreviated as M_8_0X_2_0. The material on which coatings were deposited is 1020 steel, austenitized for 1h at 880 C, water quenched, and tempered at 180 C for 1h. This heat treatment resulted in a low carbon martensite structure with a hardness of HRC35-45. After cleaning, shot blasting and preheating the steel to about 200 C, the authors sprayed a thin Ni-Al alloy layer of about 0.1--0.15mm in thickness onto the specimen by means of an oxygen-acetylene torch to provide better bonding of the coating with substrate. Then the M_8_0X_2_0 and M_8_0X_2_0+8%CeO_2 alloy coatings were sprayed to a thickness of ...
The biological age (BA) of the majority of the liquidators of the consequences of the radiation accidents in the Navy and of the liquidators of the Chernobyl' APS accident exceeds the medium standard and the DBA (due BA). The index of the BA can be a characteristic of the influence of the social-hygienic factors on the health condition of the Special Risk Subunit--the liquidators of the consequences of the radiation accidents. It was established, that the radiation influence concerns to the factors dramatically increasing the BA and the rate of senescence of the liquidators of the consequences of the radiation accidents. PMID:21809627
The experimental device for generation of undulator radiation in terahertz wavelength region by use of undulator with ferromagnets is created. The device is based on a beam of a microtron with the energy 7.5 MeV. The radiation wavelength is 200 mu. Registered spontaneous radiation has a power 10{sup -6} W at a current of a beam 2 mA in a pulse. With the optical resonator, in a mode, the amplification of 6% is received, that in sometimes is more than the expected value. This effect is explained as a result of partial coherence of radiation.
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation.
Characteristics of the Ukrainian NSA NRI radiation facility for scientific researches and developments of industrial radiation technology are performed. Parts of the facility, design peculiarities of technical tools are described. Biological protection of the facility and radiation protection system, transport line, systems of technical provision and radiation measurements are discussed
The radiation burden of the people of the GDR in relation to biomedical radiography altogether as well as organ doses, gonad doses and genetically significant doses in detail are outlined. The concepts of radiation protection and standards of radiographic examination are demonstrated. Possibilities of influencing radiation exposure by scientifically based indication of X-ray examination, application of new and improvement of usual examination techniques are discussed with regard to quality assurance and control. Proposals concerning the reduction of radiation exposure of the GDR population are presented.
High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.
Correlation characteristics of quantum noise on the shadow radiation image (RI) of the object under nondestructive testing are studied. Mathematical model of RI occasional distortions is derived. The model takes into account the parameters of object under testing and of radiation beam by radiation quanta flux density. The results obtained can be used as a component in the process of investigation of various radiation testing systems
Coherent oscillator radiation is considered. A comparison is made with classical particle radiation with gauss distribution. Decay probability for coherent state in spontaneous radiation is estimated. The method suggested for describing harmonic oscillator allows to separate the effect of classical field radiation from quantum description of particle state within the framework of a self-consistent quantum mechanical problem.
A new type of radiation which occurs when particles are accelerated in the field of a longitudinal wave and in a transverse magnetic field is studied. The characteristics of such spontaneous radiation are obtained, and the influence of collective effects on the radiation is analyzed. The application of the findings to the theory of free electron lasers is discussed. 8 references.
Objectives To provide direct estimates of risk of cancer after protracted low doses of ionising radiation and to strengthen the scientific basis of radiation protection standards for environmental,...Full Text Available
Forty-four patients with histologically proven Hodgkin's disease underwent initial treatment with extended-field radiation therapy. Nineteen of these patients also received combination chemotherapy....Full Text Available
Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).
Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation...Full Text Available
Analytical method of theoretical simulation of collective hydrodynamic instabilities of intensive flows of discrete radiators, interacting with each other only through the coherent fields of their spontaneous radiation in corresponding media was suggested...
... Top of page Testing Radiation coming from granite countertops results from natural radioactive material in the granite. Identifying the presence and concentration of radioactive elements in granite requires expensive and sophisticated portable instruments or laboratory equipment. These instruments and equipment require proper calibration, and interpretation of ...
The different radiation loads caused by natural and artificial radionuclides are compared in this paper. This examples will serve to illustrate that the problem of population exposure to radiation can only be solved in consideration of all components and to show which effects of the radiation from natural sources are of special importance in this connexion. (orig./AK).
The problem of optimizing a horn radiator of electromagnetic waves for the reflection coefficient and the coefficient of transformation of the fundamental mode into higher order modes is solved. Optimization is performed by means of selecting a combined shape of the radiator generatrices.
The thermal stability of low-friction Me-C/a-C:H coatings is important for their potential applications in the tool and automotive industry. Recently we showed that CrC _x/a-C:H coatings prepared by unbalanced magnetron sputtering of a Cr target in Ar + CH_4 glow discharges exhibit a nanocomposite structure where metastable fcc CrC nanocrystals are encapsulated by an a-C:H phase. Here, we present the structural evolution of these nanocomposite CrC/a-C:H coatings during annealing. High-temperature X-ray diffraction in vacuum and differential scanning calorimetry (DSC) combined with thermo-gravimetric analysis in Ar atmosphere indicate decomposition of the formed metastable fcc CrC phase and subsequent formation of Cr_3C_2 and Cr_7C_3 and structural transformation of the a-C:H matrix phase towards higher sp"2 bonding contents at temperatures above 450 deg. C. Combined DSC and mass spectrometer analysis as well as elemental ...
Suspension direct current plasma spraying allows achieving finely structured coatings whose thickness is between few tens and few hundreds of micrometres. Drops (200-300 ?m in diameter) or liquid jets are mechanically injected in the plasma jet. With radial injection they are rapidly (a few ?s) fragmented into droplets (a few ?m in diameter). The latter are vaporized (in a few ?s) and the solid particles contained in suspension droplets are accelerated and melted by the plasma jet. As in conventional plasma spraying (CPS), much smaller splats (with diameters between 0.2 and 3 ?m and thicknesses between 30 and 200 nm) are arranged in layers up to form the coating. The low inertia of particles requires spray distances between 40 and 60 mm which induces plasma heat fluxes up to 22 MW m-2 participating in coating densification. Even more than in CPS, the plasma jet fluctuations, particularly for plasmas containing di-atomic ...
The HT-28 and 29 irradiation capsules are part of a cooperative agreement between GA and ORNL designed to evaluate irradiation performance of unbonded BISO and TRISO coated ThO_2 fertile fuel particles. The capsules will contain a total of 44 different positions uniformly divided between each capsule. The positions in HT-29 are designated for operation at 900"0C over a fast fluence increment between 5.4 to 10.7 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/. Positions in HT-28 are divided into two sections: 11 positions at 1250"0C to receive a fast fluence exposure between 7.8 and 8.6 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/ and 11 positions at 900"0C designed for a 4.3 to 6.9 x 10"2"1 n/cm"2 (E > 0.18 MeV)/sub HFIR/ fast fluence exposure. Both capsuls are to serve as an evaluation test to characterize the performance of BISO OPyC coatings deposited from mixed-gas (acetylene-propylene). The OPyC variables tested will be density, ...
The surface of low alloy steel (En40B) has been engineered in the plasma of a glow discharge via plasma nitriding and ion plating of titanium nitride (TiN) coatings on the nitrided substrates with the purpose of enhancing the surface properties and fatigue strength. The nitriding response of the steel has been accessed by the evaluation of phase composition, layer thickness, hardness profile, residual stresses and nitrogen and carbon distributions. The wear and fatigue characteristics of the plasma-nitrided steel have been investigated and simple models have been developed to describe the influence of such properties as depth and strength of the nitrided case on the fatigue limit and load-bearing capacity of the nitrided steel. In order to further improve the tribological properties and load-bearing capacity of the low alloy steel, a duplex plasma surface-engineering technique has been developed. This is achieved by plasma nitriding the steel first so as to produce ...
The particle surface of Li[Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}]O{sub 2} was modified by AlF{sub 3} as a new coating material to improve the electrochemical properties in the high cutoff voltage of 4.5 V. The AlF{sub 3}-coated Li[Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}]O{sub 2} showed no difference in the bulk structure compared with the pristine one and the uniform AlF{sub 3} coating layers whose thickness is of about 10 nm covered Li[Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}]O{sub 2} particles, as confirmed by a transmission electron microscopy. The AlF{sub 3} coating on Li[Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}]O{sub 2} particles improved the overall electrochemical properties such as the cyclability, rate capability and thermal stability compared with those of the pristine Li[Ni{sub 1/3}Co{sub 1/3}Mn{sub 1/3}]O{sub 2}. Such enhancements were attributed to the presence of the stable AlF{sub 3} layer which acts as the ...
An optical klystron is built in the 800 MeV electron storage ring at University of Science and Technology of China for harmonic super-radiation generation. In single bunch operation mode the repetition rate of the spontaneous radiation pulses is about 4.533 MHz, and the repetition rate of the seed laser pulses is about 3 Hz, while the radiation pulse duration is 300 ps. For measuring harmonic radiation a high on/off ratio ICCD is used as an optical switch to reject spontaneous radiation pulses of high repetition rate
The document published under A/63:46 and titled report of the scientific committee of United Nations for the study of ionizing radiations effects, gives the situation of the fifty sixth session of the committee that stood at Vienna from the 10. to 18. july 2008. In the chapter 3 of this report the writers summarize the strategic planning and the working program of the scientific committee for the period 2009-2013. They note that the committee worry about the inadequate means, particularly in personnel. The priorities for the given period will be the medical exposure of patients, the radiation levels and the effects of energy production, the exposure to natural radiation sources and the improvement of the understanding of the effects of the low doses radiation exposure. (N.C.)
Nov 8, 2010 ... Ihring Mission 11, the radiation dosimetry measurement system functioned normally and provided data on the Earth's trapped radiation belts ...
Selection of the appropriate radiation quality is an important aspect of optimisation for every clinical imaging task in radiology, since it affects both image quality and patient dose. Spreadsheet...Full Text Available
By proposing the four-dimensional, reciprocity transformations the appropriate condition for superluminal electromagnetic Cerenkov radiation is obtained by introducing the hypothesis that tachyons possess vector energy and scalar momentum.
...References | Radiation Protection | US EPA This page provides links to the reference material on EPA's Radiation Protection Web site. U.S. EPA/...OAR/ORIA/Radiation Protection Division Jump to main content. Radiation Protection Contact Us Search: All EPA This Area You are here: EPA Home ... Radiation Protection References PageName Technical Users General Public Reporters Librarians Students/Teachers PROGRAMS TOPICS REFERENCES References The Reference Section provides general material that support the ...other sections of EPA's Radiation Protection Web site. You will find links within the information to related pages throughout the Radiation Protection , EPA ...
The fundamental product of tetracycline hydrochlorine gamma radiolysis was separated in its solid state. From the results of spectroscopic studies it has been established that it is des-N,N-dimethylaminotetracycline.
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-{epsilon} model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to ...
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-? model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the ...
... iFfficiency-en- enhanced spontaneous radiation at the free-electron- ... as enhanced spontaneous radiation at the free-electron-laser wavelength. ...
The introduction of tolerance to radiation (''radiation-hardness'') into large electronic systems is one of the major tasks to which this Handbook will be put. The practices recommended here for inculcating radiation-tolerance in equipment require advanced physical modeling techniques, precise engineering procedures, and firm assurance procedures. The degree to which these procedures should be used in an equipment project can be measured by the severity of the raw radiation environment, the desired reliability of the system, and the requirement of that project for radiation-sensitive technologies. The balance of device/circuit design versus shielding will depend on whether the radiation is highly penetrating -- as in isotope handling or military environments -- or readily attenuated, as in space. In this chapter the authors have attempted to summarize the ...
When energetic bunches of electrons traverse an undulator field, they can spontaneously emit radiation both coherently and incoherently. Although it has generally been assumed that undulator radiation is incoherent at wavelengths short compared to the longitudinal size of the electron bunch, several recent observations have proved this assumption false. Furthermore, the appearance of coherent radiation is often accompanied by a significant increase in radiated power. Here we report observations of strongly enhanced coherent spontaneous radiation together with direct measurements, using transition radiation techniques, of the electron distributions responsible for the coherent emission. We also report demonstrated enhancements in the predicted spontaneous radiated power by as much as 6x10"4 using electron bunch compression. copyright 1996 ...
... Except for isolated radiation accidents over the ensuing years, little practical experience has been gained in the treatment of thermal injuries ...
... spontaneous radiation of amplifiers within a relatively w~de range of ... pulse widths are 20-30ns, while amplified spontaneous radiation pulse ...
Superparamagnetic MFe{sub 2}{sup 3+}O{sub 4} (M=Mn{sup 2+}, Fe{sup 2+} and Co{sup 2+}) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r{sub 2}/r{sub 1}, for MnFe{sub 2}O{sub 4}, Fe{sub 3}O{sub 4} and CoFe{sub 2}O{sub 4} were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T{sub 2} contrast agents for MRI.
Superparamagnetic MFe23+O4 (M=Mn2+, Fe2+ and Co2+) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r2/r1, for MnFe2O4, Fe3O4 and CoFe2O4 were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T2 contrast agents for MRI.
The alloying of steel surface with aluminum (Al) using Microsecond-pulsed Intense Electron Beams (MIEB-Al) was developed and optimized in order to be used for improving the corrosion resistance of the 316, 1.4970 and T91 steels, exposed to liquid Pb and Pb-Bi-eutectic. The procedure consists in two steps: (i) coating the steel surface with Al or an Al-containing alloy layer and (ii) melting the coating layer and the steel surface layer using intense pulsed electron beam. In order to cover the steel surface with an homogeneous and crack-free Al-alloyed layer, the following experimental conditions are required: Al coating thickness range 5-10mm, electron kinetic energy 120keV; pulse duration 30ms; energy density 40-45J/cm2; number of pulses 2-3. Using the mentioned procedure, the corrosion r...
We have investigated the possibility to use a microwire of BiSn to design an anisotropic thermoelectric generator. The glass-coated microwire of pure and Sn-doped bismuth was obtained by the Ulitovsky method; it was a cylindrical single-crystal with orientation (1011) along the wire axis; the C3 axis was inclined at an angle of 70 degrees to the microwire axis. It is found that doping of bismuth wires with tin increases the thermopower anisotropy in comparison with Bi by a factor of 2 - 3 in the temperature range of 200-300 K. For a Bi microwire with a core diameter of 10 ?m with a glass coating with outer diameter of 35 ?m, the transverse thermopower is ? 150 ?V/(K*cm); for BiSn, 300 ?V/(K*cm). The design of an anisotropic thermogenerator based on BiSn microwire is proposed. The miniature thermogenerator will be efficient for power supply of devices with low useful current. In addition to the considerable thermopower anisotropy of BiSn wires ...
The present invention provides a fuel cladding tube having an excellent corrosion resistance and thus a long life, and a suitable manufacturing method therefor. Namely, in the fuel cladding tube, the outer circumference of an inner layer made of a zirconium base alloy is coated with an outer layer made of a metal more corrosion resistant than the zirconium base alloy. Ti or a titanium alloy is suitable for the corrosion resistant metal. In addition, the outer layer can be coated by a method such as vapor deposition or plating, not limited to joining of the inner layer material and the outer layer material. Specifically, a composite material having an inner layer made of a zirconium alloy coated by the outer material made of a titanium alloy is applied with hot fabrication at a temperature within a range of from 500 to 850degC and at a fabrication rate of not less than 5%. The fabrication method includes any of extrusion, ...
A systematic study was made on MoSi{sub 2}-based nanolayer coatings. Alternating layers with thickness 1-20 nm were prepared by sputtering. Nitrided MoSi{sub 2} has a very high crystallization temperature, >1000 C, and MoSi{sub 2}Nx (x=3-4) can be used as a stable second phase reinforcement or diffusion barrier coatings. Mechanical properties depend strongly on phase and morphology of the layers: hardness and modulus is significantly increased in the crystallization. The nanolayers have much higher hardness but lower modulus (which project higher toughness in the nanolayers). Wear resistance is improved with decreasing layer thickness. Single phase MoSi{sub 2}Nx (x=0-4.2) has a wide range of hardness and modulus with varying N content and annealing, suggesting the possibility of engineering MoSi{sub 2}Nx to produce different material properties for different mechanical applications. Most of this paper is made up of viewographs.
Slurry aluminizing is one method of protecting titanium alloys and intermetallics at temperatures at which oxidation would otherwise significantly degrade mechanical properties. The technique produces a continuous layer of alumina-forming TiAl_3 on exposed surfaces. The influence of composition, film thickness, and diffusion temperature upon the oxidation resistance of these slurry aluminides was studied in cyclic tests to 816degC (1500deg F). Degradation of slurry aluminized #beta#-titanium alloy and #alpha#-Z titanium aluminide intermetallic occurs by localized oxidation at cracks in the coating layer. These cracks are probably due to mismatch of coefficients of thermal expansion between the coatings and substrates. Addition of silicon to the slurry modifies the oxidation behaviour around a crack by introducing a continuous layer of titanium silicide at the boundary of the aluminide coating and substrate, thereby ...
High-quality solar cells have been fabricated by utilizing localized argon-ion laser decomposition of silver neodecanoate spun onto diffused silicon substrates and subsequent electroplating. Early adhesion problems during electroplating have been carefully studied and finally solved using a novel coating procedure. The laser-metallized solar cells have been characterized using lighted and dark current-voltage measurements and compared with baseline cells metallized using standard photolithographic procedures. Non-AR-coated cell efficiencies ranging from 10 to over 11% have been obtained for the laser-metallized cells, comparable with the best baseline cells. The laser-metallized cells have 30 to 40% lower series resistance than the unsintered baseline cells, indicating that in-situ sintering takes place during laser writing. A dramatic new and simpler laser metallization process on which patent protection is currently being sought has yielded ...
Functionalizing nanoparticle surfaces is essential for achieving homogeneous dispersions of monodisperse particles in polymer nanocomposites for successful utilization in engineering applications. Functionalization reduces the surface energy of the nanoparticles, thereby limiting the tendency to agglomerate. Moreover, reactive groups on the surface can also participate in the polymerization, creating covalent bonds between the inorganic and organic phases. In this paper, a fluidized bed inductively coupled plasma (FB-ICP) reactor is used to break apart the agglomerates and functionalize commercial TiO2 nanoparticle powders in a batch of several grams. The fluidized bed could be implemented into a continuous flow reactor, potentially making this a viable method to treat larger quantities of commercial powders. The particles are treated with acrylic acid (AA) and tetraethylorthosilicate (TEOS) plasma and the functionalized particles were collected separately from bulk powder. High ...
The major objective of this work is to seek for new solutions that can lead to significant lifetime improvement of submerse lines which experience severe wear processes on the polymeric layer coating used for protection of the touch down point (TDP) region. Four different materials were selected as possible candidates for the coating layer of this critical region. They are commercially available and posses well known processing technologies. The materials are two polymers: nylon 66 and polyacetal; and two composites: nylon 66 reinforced with 13 or 33% glass fiber. Stress-strain behavior was evaluated using two deformation rates in order to characterize the viscoelastic behavior proper of polymeric materials. It was observed that increasing the amount of glass fiber in the matrix leads to a stronger material and a consequent decrease of elongation to break. Additionally, abrasion tests were carried out using a Taber equipment in three distinct ...
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that ...
The University of Georgia, in collaboration with GE Global Research, has investigated the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs. The final goal of the project was the design and fabrication of a high-efficacy white light UV-LED device through improved geometry and optimized phosphor coatings. At the end of the research period, which was extended to seamlessly carry over the research to a follow-up program, we have demonstrated a two-fold improvement in the conversion efficiency of a white light LED device, where the increase efficacy is due to both improved phosphor quantum efficiency and lamp geometry. Working prototypes have been displayed at DOE sponsored meetings and during the final presentation at the DOE Headquarters in Washington, DC. During the first phase of the project, a fundamental understanding of quenching processes in UV-LEDs was obtained, and the relationships that ...
A novel composite film, comprising of hydrophobic ionic liquid (IL), multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (GNP), was fabricated and characterized. The GNP was introduced through electrochemical deposition on IL-MWNT gel film coated glassy carbon electrodes (GCE). Experiments showed that both IL and MWNTs could facilitate the GNP deposition. With GNP the composite film exhibited smaller electron transfer resistance and higher sensitivity in sensing guanine (G) and adenine (A). Under the optimized experimental conditions, the anodic peak currents were linear to the analyte concentration in the ranges of 0.008-2.0 {mu}M. The detection limits were down to nanomole level after an accumulation of 150 s on open-circuit. In addition, on the composite film coated GCE, the anodic peaks of G and A were well separated, and their response sensitivities kept almost unchanged no matter whether they coexisted or not. This proposed ...
A novel composite film, comprising of hydrophobic ionic liquid (IL), multi-walled carbon nanotubes (MWNTs) and gold nanoparticles (GNP), was fabricated and characterized. The GNP was introduced through electrochemical deposition on IL-MWNT gel film coated glassy carbon electrodes (GCE). Experiments showed that both IL and MWNTs could facilitate the GNP deposition. With GNP the composite film exhibited smaller electron transfer resistance and higher sensitivity in sensing guanine (G) and adenine (A). Under the optimized experimental conditions, the anodic peak currents were linear to the analyte concentration in the ranges of 0.008-2.0 ?M. The detection limits were down to nanomole level after an accumulation of 150 s on open-circuit. In addition, on the composite film coated GCE, the anodic peaks of G and A were well separated, and their response sensitivities kept almost unchanged no matter whether they coexisted or not. This proposed ...
Power plant components exposed to environments such as water and soil are susceptible to severe corrosion. Many times the effect of corrosion in power plant components can be catastrophic. The problem is aggravated for underground pipelines due to additional factors such as large network of pipelines, proximity to earth mat, high voltage transmission lines, corrosive chemicals, inadequate approach etc. Other components such as condenser water boxes, internals of pipelines, clarifier bridge structures, cooling water inlet gates and pipes etc. which are in continuous contact with water, are subjected to severe corrosion. The nature and locations of all such components are at places which are not accessible for routine maintenance and hence they require long term reliable protection against corrosion. Experience has shown that anti-corrosive coatings are inadequate in preventing corrosion and due to their location regular maintenance coatings are ...
A combined PVD/PECVD process for the vacuum deposition of titanium containing amorphous hydrogenated carbon films is described. Elemental compositions of the deposited films have been determined by in situ core level photoelectron spectroscopy (XPS). The long-term stability of the plasma process has been demonstrated. Target poisoning has not been observed. We have fabricated optical selective surfaces by the deposition of a-C:H/Ti multilayers onto aluminum substrates. Even though we have not optimized layer thicknesses and stoichiometries so far, the experimental results are promising: solar absorptance {alpha}{sub S} of 0.876 and thermal emittance {epsilon}{sub 100C} of 0.061 have been achieved yielding an optical selectivity sis defined as{alpha}{sub S}/{epsilon}{sub 100C} of 14.4. Accelerated aging tests of these coatings have demonstrated their aging stability: the service lifetime is predicted to amount to more than 25 years. Raman spectroscopy has been used ...
Phenolic resins have made a major breakthrough in the field of high technology in 80's. These are now active participants of "high tech' areas ranging from electronics, computers, communication, outer space, aerospace, advanced materials, bio materials and technology. A phenol - formaldehyde (1:1.5) resin having resin content of 70% synthesized in the laboratory has been applied for wood coating and reinforcing glass fiber. The weatherability and solvent resistance of these items have been studied and results discussed keeping in view the envisaged application for structural materials and chemical equipment. The toxic materials released during contact with solvents for chemical applications and during degradation general have been monitored. The results are discussed with reference to environmental pollution due to these resins and their composites under different conditions. (authors)
This paper describes the basic principles underlying the operation of low heat loss engines and the magnitude of the efficiency improvements that are theoretically achievable. The effect of varying degrees of thermal insulation on various operating parameters is examined in some detail, as is the relationship between degree of insulation and ceramic coating thickness. The effect on ceramic materials of severe surface temperature oscillations and the resultant thermal stress gradients is also discussed. In the following section, the paper describes methods of construction adopted both for ceramic inserts and coatings, and rig tests for the assessment of thermal fatigue under both load and firing cycling. The paper does not attempt to draw any general conclusions.
Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characterist...
Alumina-reinforced carbon nanofiber nanocomposites were prepared using different routes; powders mixture, colloidal route and sol?gel process followed by spark plasma sintering (SPS). CNFs/xAl2O3 (x = 10?50 vol.%) were prepared through nanopowders mixing in a high-energy attrition milling. The main limitations in the preparation of this kind of nanocomposites are related to the difficulty in obtaining materials with a homogeneous distribution of both phases and the different chemical nature of CNFs and Al2O3, which causes poor interaction between them. A surface coating of CNFs by wet chemical routes with an alumina precursor is proposed as a very effective way to improve the interaction between CNFs and Al2O3. An improvement of 50% in fracture strength was found for similar nanocomposite ...
The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process cou...
Carbon steel is frequently used to construct concentrated sulphuric acid storage tanks. This paper discussed the corrosion performance of carbon steel tanks and outlined the underlying mechanisms responsible for major corrosion modes. Analyses of hydrogen grooving and dilute acid corrosion failure mechanisms were presented. Recent corrosion-induced leak failures were also discussed. The use of anodic protection and organic coatings as a corrosion control measure was also evaluated. The results of laboratory studies that were conducted to understand corrosion-induced failures showed that carbon steel electrodes exhibited transpassive corrosion at relatively high anodic potentials, while stainless steel electrodes exhibited transpassive corrosion at anodic potentials less than 1 V. It was concluded that corrosion-induced leaks can be prevented by using anodic protection and baked phenolic coating technologies. 23 refs., 9 figs.
In the beam pipe of the positron damping ring of the Next Linear Collider, electrons will be created by beam interaction with the surrounding vacuum chamber wall and give rise to an electron cloud. Several solutions are possible for avoiding the electron cloud, without changing the bunch structure or the diameter of the vacuum chamber. Some of the currently available solutions for preventing this spurious electron load include reducing residual gas ionization by the beam, minimizing beam photon-induced electron production, and lowering the secondary electron yield (SEY) of the chamber wall. We will report on recent SEY measurements performed at SLAC on TiN coatings and TiZrV non-evaporable getter thin films.
One of the significant factors of neutron radiographic image degradation is scattering blur from the object. A practical method is described to enhance image quality by eliminating the overlapping of scattered thermal neutrons component from the objects in ETRR-2 neutron radiography facility, using aluminum Gd-coated antiscatter grid. The MCNP code was used to determine the optimum grid dimensions that will reduce the scattered thermal neutrons from the object. An experiment was performed to determine the optimum grid height and irradiation time that gives the best image with acceptable geometric unsharpness. Using the MCNP code it was found that 97% of the scattered neutrons were removed by the grid. The wall dimensions and Gd coating are so small that the facility resolution cannot detect the image pattern superposition on the film.
This is a process for manufacturing a semi-rigid, folding solar generator manufactured from several coated solar cells (Cics), which has at least two folding parts connected together so as to turn by hinges, characterized by the following stages of the process: a) On the back of matrix subsections, in order to cover the connector, carbon fibre strips are glued on, which project over the upper or lower edge of each matrix subsection. b) The projecting ends of adjacent carbon fiber strips are connected with two carbon fibre strips. c) At least two matrix subsections are fixed in separately manufactured carbon fiber frames, and d) the carbon fiber frames, together with the matrix subsections are connected via hinges to a solar generator.
This paper described a risk control management tool that has been developed by Petrobras Petroleo, the largest Brazilian oil company and one of the world's leading oil companies. The system covers health, safety and environmental (HSE) issues regarding pipeline construction projects. The limitations of traditional safety management systems for coping with the critical problems related to environmental safety issues were discussed. In particular, this paper described how the HSE tool evaluates the risks resulting from the following aspects of onshore pipeline construction and assembly: establishing right-of-way and route locations, transporting pipe, developing the construction site, opening the trench, pipe laying, pipe bending, concrete external coating, welding, external anticorrosive coatings, pipe placement backfilling, hydrostatic testing, maintenance operations, and pipeline commissioning. 6 refs., 1 tab.
The major goal of this contract is to define fine grid lines using laser-assisted metallization and to demonstrate the fabrication of high-efficiency cells using this process. During this period a solar cell run was completed using low-resistivity float-zone silicon. Grid lines were written by spinning silver neodecanoate solution after the Ti-Pd evaporation. This run produced cell efficiencies as high as 11.2% prior to antireflection coating and 16.6% after the AR coating. Open-circuit voltage was approx.604 mV and short-circuit current density was approx.35 mA/cmS.
Methods for improving the sensitivity of scintillation cells for radon concentration measurements were studied with emphasis on improving light collection efficiency. This allows the length and hence the volume of the cell to be increased. Variables studied were choice of scintillator material, its method of application and thickness, length of cell, cell material, type and configuration of reflectors, choice of photomultipliers, and factors affecting background. Response from various areas of the cell surface was studied with an alpha source and with radon filling. Coating the window with phosphor was found to be counter-productive. The optimum results obtained were with the inside of the cell (other than the window) covered with a thick layer of ZnS(Ag), or with a thick layer of reflective material coated with a thin layer of phosphor. With it, a 10 cm diameter plexiglass cell can be extended to at least 50 cm length without difficulty from ...
Methods for improving the sensitivity of scintillation cells for radon concentration measurements were studied with emphasis on improving light collection efficiency. This allows the length and hence the volume of the cell to be increased. Variables studied were choice of scintillator material, its method of application and thickness, length of cell, cell material, type and configuration of reflectors, choice of photomultipliers, and factors affecting background. Response from various areas of the cell surface was studied with an alphy source and with radon filling. Coating the window with phosphor was found to be counter-productive. The optimum results obtained were with the inside of the cell (other than the window) covered with a thick layer of ZnS(Ag), or with a thick layer of reflective material coated with a thin layer of phosphor. With it, a 10 cm diameter plexiglass cell can be extended to at least 50 cm length without difficulty from ...
DZ4 substrates were coated with NiCoCrAlY by plasma spray and subsequently treated by high current pulsed electron beams(HCPEB) of different parameters. The surface microstructure, phase structure and high temperature oxidation resistance were studied. It has been shown that as a result of the HCPEB treatment the loose and rough structure remelted and the surface became smooth. Smooth microregion, craters and cracks appeared on the surface. The ?' phase manifolded and there was no visible thermal stress. The oxidation test at 900 degree C for 100 h showed that a more compact and successive ?-Al_2O_3 scale was formed on the surface of the samples after HCPEB irradiation, which improved the oxidation resistance of the NiCoCrAlY coatings obviously. (authors)
Means of intensifying heat transfer with nucleate boiling, based on boiling under constrained conditions (in slots, on a capillary-porous surface) are the most promising since a high intensity of heat transfer is ensured. In the present work we attempt to evolve the main assumptions for the physical model of the process of vapour formation under constrained conditions and to extend them to the boiling of cryogenic liquids on surfaces with a capillary-porous deposit; also, the results are given of experimental investigations of heat transfer with the boiling of nitrogen, oxygen and hydrogen at atmospheric perssures and below on capillary-porous surfaces of various metals of different structure produced by an electric arc method of gasothermal spray coating.
The influences of maltodextrin (MD) addition and multi-layer formation on the freeze-thaw stability of ?-lactoglobulin (?-Lg)-stabilized oil-in-water beverage emulsions (0.1 wt% corn oil, 0.006 wt% ?-Lg) were investigated. Various beverage emulsions were prepared depending on MD concentration (0?20 wt%), its dextrose equivalent (M150 or M250), and the presence or absence of additional polysaccharides (pectin, alginate, or ?-carrageenan) coatings around the emulsion droplets. All emulsions (?-Lg- and ?-Lg-polysaccharide-coated emulsions) were unstable to experimental freeze-thaw cycling in the absence of MD. In the presence of MD, all emulsions containing M250 had better stability to droplet aggregation than those with M150, regardless of MD concentrations and freeze-thawing. The optimum co...
b-carotene, a natural antioxidant, beneficial form human health prospective. In this study we had examined the recovery of b-carotene form mesoporous carbon coated monolith (MCCM) by batch process. Desorption kinetics and isotherm studies were carried out by using n-hexane as an eluent. Isotherm studies showed better applicability of Langmuir model. The first-order two-compartment three-parameter kinetics model as a function of initial loading concentration and reaction temperature was applied. It was observed that b-carotene desorption process is controlled by both rapid and slow desorption. Results showed that the slow desorption fraction increases from 0.8446 to 0.9007 with increase in initial loading concentration from 10.83 to 39.72mg/g while, the slow desorption fraction decreases fr...
An innovative hybrid powder prepared using computer simulation allowed development of a new foundation having a fine, smooth texture that has never been achieved before. The optical structure/design of the powder was based on the results of measurements and analyses conducted on the optical characteristics of a baby's delicate skin, which is the envy of many women. To obtain the optimal optical characteristics, the finite differential time domain (FDTD) method for solving Maxwell's differential equation by difference and time domain was applied to the computer simulation method. For synthesis of the hybrid powder based on the optical model, a proprietary shape regulation coating technology was used in which flaky substrates were coated with microspherical forms of barium sulfate crystals. ...
Abstract A novel and convenient protocol for the preparation of an open-tubular column coated with chitosan-silica hybrid using chitosan and silane-coupling agent (-glycidoxy-propyltrimethoxysilane) was developed for CEC, in which, chitosan was covalently bonded to the inner wall of a fused-silica capillary using -glycidoxy-propyltrimethoxysilane as a cross-linking agent. The stationary phase was hydrophilic due to the chitosan-silica hybrid with abundant amine and hydroxyl functional groups. The chromatographic characteristics of the column were evaluated by the separation of some organic acids and inorganic anions. The column showed good selectivity for nucleotides, aromatic acids, and inorganic anions. The mechanism for the separation of these compounds was primarily based on the hydrop...
A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O40^3^- (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N^+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in ...
Superalloys, such as Inconels and Incoloys, are extensively used where high strength is a requirement. However, where these materials are required to slide against one another, particularly with poor or no lubrication, high friction levels and seizure are commonly seen to occur, which can cause component failure. In this work seizure characteristics of three superalloys (Inconel 718 and Incoloys 945 and 945X) were investigated, uncoated, coated with Armoloy (a hard, thin, dense chrome coating with a micro-nodular surface texture) and plasma nitrided in dry sliding conditions. A rig purpose built for initiating seizure was used. It involves sliding a ball against a disc at constant speed while the load is increased. Tests are designed to last less than one rotation so that the wear scar can...
It is generally known that a number of metallic glasses have excellent corrosion resistance in a variety of chemically hostile environments. Consequently, the use of laser cladding to coat a massive crystalline material such as aluminium with a layer of a metallic glass has obvious advantages. In this paper, the authors will show that the formation of a predominantly amorphous layer of Zr_6_0Al_1_5NI_2_5 alloy by laser processing is possible, if the obstacles to amorphization are overcome. In addition, evidence of the excellent corrosion resistance of this alloy in a NaCl solution will be given. A comparative study of the corrosion behavior of this amorphous alloy with pure aluminium and Al-Cr alloy will be done, in order to complete previous studies of laser processed coatings of aluminum substrates.
It is necessary to identify those measurable soil parameters which dictate the severity of the corrosion problem for coated irons and steels. When this is done, meaningful accelerated aging tests can be designed to validate the reduced corrosion rate for the planned coating. The following discussion introduces the important concepts and measurement parameters in the (a) design of accelerated aging tests, and (b) evaluation of the planned installation site for corrosion potential. Certain combinations of soil oxidation reduction potential (ORP) or electric potential (Eh), acidity (pH), fertilizer, water table, and soil hydraulic conductivity can result in severe corrosion of buried steel/iron vessels. If there are power lines nearby, additional loss of vessel material to the soil will occur. These factors are discussed.
Corrosion is said to be the most dominant factor which affects the physical life of ships and offshore structures. In order to secure the structural safety of ships and offshore structures, it is necessary to take measures to corrosion based on the prediction of condition of progressive corrosion. But such prediction is difficult because the behavior of corrosion`s progress is probabilistic. In this paper, probabilistic model, which could evaluate the degradation of coatings and the successive corrosion of steel members, was proposed in order to explain the tendency of the actual corrosion conditions of existing ships. Then, statistical inferences on the proposed model were made by applying the actual data on plate thickness measurements of Bulk Carriers` Cargo Hold. And validity of the proposed model was verified.
Background: As the global population ages, support for family caregivers who provide the bulk of care to community-dwelling older people is becoming ever more important. However, in many countries, homecare-service practitioners currently do not follow a systematic approach to assessing and responding to caregiver needs. Objectives: The aim of this study was to explore the experiences of caregivers and practitioners who took part in a field test of the Family Caregivers Support Agreement (FCSA) tool, a modified version of the Carers Outcome Agreement Tool (COAT) initially developed as the result of an Anglo-Swedish study. Both the COAT and the FCSA are designed to facilitate partnerships between caregivers and practitioners so that needs assessment and subsequent support services are negot...
A superhydrophobic SiO2/nylon 6,6 nanocomposite coating was fabricated by a facile casting process. Compared with the intrinsically hydrophilic pure nylon 6,6, the as-prepared coating displayed a superhydrophobic property in the pH range from 1 to 14. It was also found that the resulting water contact angles of the as-prepared surface were always larger than 159?, but the sliding angles had an obvious decrease from about 33.4??1? as the content of SiO2 nanoparticles increased. In addition, a transition from the transitional superhydrophobic state between Wenzel?s and Cassie?s state to the Cassie?s state was observed.
The following topics are discussed: insertion of incorrect bases in DNA; ability of DNA polymerase to copy uv-irradiated DNA; role of enzymes in repair of DNA; effects of uv radiation on molecular weight of DNA; photoreactivation; repair of DNA in Escherichia coli and xp cells following uv radiation; and synchrotron radiation studies on DNA repair. (HLW)
The book is divided into two approximately equal parts. The first four chapters are relatively lengthy and cover the basic principles of radiation biology, carcinogenesis and therapy, along with a brief introduction to radiological physics to orient the reader without background in this specialized related discipline. The remainder consists of twenty-four relatively brief chapters, each covering the radiation biology of a specific organ, tissue, or systems tissues, with emphasis on the tumorigenic and tumoricidal action of ionizing radiations.
The present state of knowledge on the influence of stray radiation on image quality and its physical description and quantification is summarized. Experimental results on the influence of physical parameters on the fraction of scattered radiation and the effect of scatter reduction by air gap technique and secondary radiation grids are committed. Open theoretical and practical problems and the limitations of common methods of scatter reduction are pointed out. (author).
Disclosed herein is a radiation detector providing for the in situ automatic sampling of fluids containing substances emitting radiation, especially Cerenkov radiation. The detector permits sampling within well casings and is self-purging such that no additional provisions must be established for the storage and disposal of contaminated fluids.
A study is made of the mechanical properties of vanadium irradiated with fast neutrons up to dose 8.6.10"-"4 dpa, as a function of the temperature of post-radiation annealing. The radiation-annealing hardening (RAH) effect is observed at 300"oC, in agreement with previous studies. It is established for the first time that RAH is accompanied by fall in ductility. A phenomenological model is described which explains the dependence of RAH on radiation dose and temperature, as well as on the content of chemically active alloying impurities. (author).
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array.
A formula is obtained which describes the kinetics of low-temperature radiation hardening caused by creation of dislocation loops of interstitial type during irradiation. The radiation hardening of aluminum and vanadium is estimated using this formula and results of experiments on studying processes of nucleation and growth of interstitial dislocation loops in these materials by transparent electron microscopy. It is shown that the proposed formula is valid for description of the kinetics of low-temperature radiation hardening.
In scattering of channeled particles by point defects and in emission of gamma rays in the spontaneous-radiation spectral region conditions are attained where the momentum transferred to the defect is taken up by the crystal as a whole. This leads to coherent and interference effects in the radiation from the crystal defects. When the longitudinal momentum transferred is zero, an induced radiation effect appears in the transitions between the states of transverse motion.
External radiation dose exceeded 5,000 rad in three cases, and intravaginal radiation dose was 5,000 rad in one case. Radiation damage including perforation was seen in the end of ileus in one case, in the sigmoid and rectum in two cases, and in the end of ileus, sigmoid and rectum in the last case. Satisfactory results were obtained by the removal of the ileocecum in the case of the damage in the end of the ileus. However, only colostomy was performed for the damage in the sigmoid and rectum.
Due to the intensity and vast number of subjects, this Bremen experts' discussion, too, could discuss only part of the problem of the possibilitiy to quantify the radiation hazard. One preliminary result is that there is no scientific proof of the harmlessness of radiation exposure during normal operation of a nuclear power plant, either within the plant or in its vicinity. Other results are that some important questions can not be answered yet, and that there are important hints on the dangers even of low radiation doses. (GL).
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of {sup 6}Li and {sup 7}Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of {sup 6}Li and {sup 7}Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of "6Li and "7Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of "6Li and "7Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)
The total radiation rate, angular distribution of the emitted energy and photon correlations of the cooperative spontaneous radiation from two atoms with different resonance frequencies and spontaneous decay rates are calculated. Contrary to the case of two identical atoms oscillations appear in the total radiation rate and the spatial distribution of the total number of emitted photons differs from the single-atom radiation pattern. The effect of the dipole-dipole near-field interaction on the time evolution of the atomic system is discussed. (author).
BackgroundTo compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated...Full Text Available
Results on defect structure study and degree of molybdenum radiation hardening irradiated by fission neutrons and medium energy alpha-particles are presented. It is shown that molybdenum irradiation by alpha-particles and neutrons leads to different degree of material hardening for the same damage level. It is established that molybdenum radiation hardening is mainly defined by radiation defect clusters visible in electron microscope whose coefficient of rigidity depends on their size. 5 refs.; 6 figs.; 2 tabs. (author).
We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition Undulator Radiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for electron beam diagnostics. We discuss Coherent Edge ...
The influence of a periodic electromagnetic field on the radiative corrections to the atomic energy levels is studied for the case of ''strong fields'' for which the interaction between the atom and field is of the order or greater than the radiative effects. The analysis is carried out on the basis of the Schwinger-Dirac equation for the propagation function of a bound electron in the field and on the basis of the density matrix in the Furry representation. It is shown that in the strong field approximation the radiative shifts and widths are manifest as radiative corrections to the quasi-energies. In super-high resolution experiments intensity effects in the radiative corrections to the atomic levels are obtained in the case of single-photon resonance. Some multiphoton processes are condidered by taking into account the effect of the field on ...
The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and ...
The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. ...
The atomic explosions in Hiroshima and Nagasaki made the name radiation itself become a nightmare. Notwithstanding this, radiation continued to serve the mankind specially in diagnosis of several human diseases and in the treatment of intractable malignancies. With their latest research tools biologists have now shown a significant shift in the earlier paradigm; even the concept that radiation initiates cancer appears to be no longer tenable. On the contrary, selective radiation doses inhibit growth of cancer cells and radiation in combination with many chemotherapeutic drugs, radiosensitizing chemicals and/or hyperthermia, is emerging as a new modality for cancer treatment which offers high therapeutic advantages. In addition, the deleterious effects of radiation can now be strategically counter poised by the use of many drugs and chemicals. This has been ...
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
Scattered radiation generated in patient and imaging system has to be considered when quality-assurance tests involve dose detection or image-quality estimations. Measurement of automatic-exposure control dose can be altered by backscattering from intensifying screens of more than 10% and the equipment transmission factor can be overestimated up to a factor of 10 when only primary radiation is used. The sensitivity of intensifying screens depends on the angle of incidence of the radiation and so primary and scattered radiation are detected differently. The quality-control aspects of anti-scatter grids are discussed. (author).
The emission of Cerenkov radiation by tachyons has been examined by using the reduced expansions of superluminal electromagnetic fields in terms of standard helicity representation of Poincare group. It has been shown that the tachyons emit Cerenkov radiation through their coupling only with subluminal electromagnetic fields and that a charged tachyon can emit Cerenkov radiation only in the media in which it travels with a velocity lower than that of light while in the usual medium in which its velocity is more than that of light, it will never emit Cerenkov radiation. (author).
Standard radiation monitoring has been conducted at Sendai nuclear power station for the purpose of estimation of 'source activity' during refueling outage and evaluation of countermeasures to reduce dose rate. Selected objects of the monitoring are radiation dose rate at maintenance area, radiation field at each equipment and piping, coolant chemistry and plant operation condition. Monitored data indicates that 'source activity' variation can be estimated to some extent using influential factors, and that evaluation of change of loose crud activity, which is presumed to be represented by the dose rate at letdown heat exchanger, is necessary to further explain change in radiation field at main work area. (author).
The authors give a survey of the somatic radiation risk in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk.
The authors give a survey of the somatic radiation ris in X-ray diagnostics. A somatic dose index is calculated for different examination methods containing the organ doses to the red bone marrow, the lung, the female breast, and the thyroid gland and evaluating their somatic significance. If this somatic dose index by which the individual radiation risk is described, is multiplied by the examination frequencies per year in the German Federal Republic, one gets the somatically significant dose index, which is a measure of the collective somatic radiation risk. In this sense, mammography has the highest, and dental radiography the lowest collective radiation risk. (orig.).
The diffusion coefficient of particles in radioactive gases has been calculated with account of random wandering of aerosols (occurrence of local fields affecting the particles; recoils accompanying radiation emitted by particles, etc.). To determine the diffusion coefficient, the method of Fokker-Planck equation derivation was used. A formula is presented for calculating the radiation-stimulated diffusion coefficient. A linear growth of the diffusion coefficient with radioactivity is noted according to the formula, the diffusion coefficient is mainly determined by the field in the radiation damage region. The aerosol radioactivity may result in a more rapid deposition of aerosols in the pipelines and aerosol purification systems. The diffusion rate grows not only in the presence of intrinsic radioactivity but in case of external radiation exposure as well.
The results of theoretical and experimental investigations, describing the effect of ionizing radiation on wood and its main components and methods for production of wood-plastic composites by means of radiation-induced chemical modification are generalized. Domestic and foreign experience in their production is systematized; physico-mechanical characteristics of new material, simulation and calculation of irradiating devices, as well as calculation and experimental study of #gamma#-radiation attenuation both by wood material and by wood of different species are given. Gamma sources ("6"0Co isotope, a hot loop of a nuclear reactor) as well as electron accelerators are considered as ionizing radiation sources.
RADSOLVER is a computer program which calculates the radiation energy transport in cavity type receivers having an arbitrary number of apertures through which collimated beams of solar radiation enter. In contrast to the common assumption of gray (or semi-gray) surfaces used in the modeling of radiation transport, RADSOLVER accounts for the wavelength-dependence of emission, absorption and reflection with a band model of the radiative properties. It is intended that this report serve both as an instruction manual for the use of the RADSOLVER code and a vehicle for presenting the underlying theory. Illustrative examples along with input and output are presented.
Outage is a specific period of time for radiation protection in a nuclear power plant, in which the radiation risk and collective dose are both at the highest level. In this article, the practice and experience of occupational exposure control in the outages of Daya Bay Nuclear Power Plant are introduced through following aspects: early involvement in outage preparation by radiation protection service, control of source term, radiation protection and safety management in the outage implementation processes, the effectiveness of the plant's safety management network and overall involvement of all staffs of the plant, experience feedback and continuous improvement in radiation protection management, etc
In radiation risk assessment it must be differentiated between somatic and genetic effect on the one hand as well as between stochastic and non-stochastic effect on the other. According to definitions of the ICRP report 26 the limit for the dose equivalent of all tissues prevents non-stochastic radiation effects. With stochastic radiation effects probably exist no threshold doses; therefore the ALARA principle must be applied concerning radiation protection. The individual risk by stochastic radiation effects in its linear, linear-quadratic and quadratic extrapolations, respectively, is discussed in detail. The effective stochastic dose equivalent (H/sub eff/) as well as collective dose and collective damage are outlined.
In Korea, the Proton Engineering Frontier Project (PEFP) is building a proton linear accelerator facility with energy up to 100MeV and a beam current of 20mA. In this study, a radiation field after shutdown in the accelerator facility of the PEFP was evaluated for the purpose of the radiation shielding by using MCNPX code. A facility modeling was performed for the accelerator tunnel building, accelerator chain, target rooms and beam experiment hall. And radiation source terms were evaluated in the facility. With this facility, model and radiation source terms, the concentration of 41Ar was evaluated and the cooling time satisfying regulation in Korea was calculated.
Delayed cerebral necroses after irradiation are to be divided into hemispheric and midline lesions, as they differ from each other in several aspects. Apart from the symptoms, they are differing in the duration of latency, in the course and prognosis, and also with regard to morphology. Though there is no doubt that radiation tolerance of cerebral midline structures is relatively limited, on biological grounds, evidence of a difference between the tolerated doses could not be given from the existent inhomogeneous radiation data, with the help of the NSD-concept. Radiation planning for the region of the head, nevertheless, carefully should avoid in every case to involve the structures of the cerebral midline.
Remote-controlled handling systems are required for work to be done in the decommissioning and dismantling of nuclear facilities. These systems are equipped with electronic devices suitable for use in working environments affected by ionizing radiation. The publication explains the step-wise progress achieved for improving the radiation resistance of electronic devices with the example of a four-quadrant controlling device for the motors of a manipulator. The radiation resistance of the device could be enhanced to radiation energies of 5.500 Gy. This means that a manipulator vehicle equipped with this controlling device can take up to approx. 15 kGy all in all, taking into account its own shielding properties. (DG).
Investigations were carried out of radiation level around Daya Bay for three times since the construction and operation Daya bay Nuclear Power Station and Lingao Nuclear Power Station in Guangdong province in the period of 1988 to 2000. As shown by the investigation, the radiation levels both in the field and indoors remains unchanged by and large but slightly higher than before on the roads. Also this paper gives the analysis of variations in radiation levels form site to site and from time to time. It was shown that, for environmental ? radiation levels measurements, typical measuring sites have significant impact on the meaning results. (authors)
Separate abstracts were prepared for 20 papers in this conference report and includes all papers in the ''engineering'' section (program E). Ocean thermal energy conversion (OTEC), moorings, cables, corrosion protection, corrosion testing, coatings, offshore platforms, pipelines, OTEC models and pilot plants, and energy transfer are topics discussed.
A new dual focal point electro-optic lens that is switchable to focusing and unfocusing is proposed and successfully demonstrated. This electro-optic lens is constructed by coating transparent fine electrodes in the Fresnel-zone plate onto a PLZT ceramic plate. Its focal length changes from 1.25 m to infinity binary at 515 nm with the external voltage of 210 V. PMID:20725208