Boat sampling technique (BST) is a surface sampling technique, which has been developed for obtaining, in-situ, metal samples from the surface of an operating component without affecting its operating service life. The BST is non-destructive in nature and the sample is obtained without plastic deformation or without thermal degradation of the parent material. The shape and size of the sample depends upon the shape of the cutter and the surface geometry of the parent material. Miniature test specimens are generated from the sample and the specimens are subjected to various tests, viz. Metallurgical Evaluation, Metallographic Evaluation, Micro-hardness Evaluation, sensitisation test, small punch test etc. to confirm the integrity and assessment of safe operating life of the component. This paper highlights design objective of boat sampling technique, description of sampling module, sampling cutter and its performance evaluation, cutting process, ...
The bobbin probe technique is basically one of the important ECT methods for the steam generator tube integrity assessment that is practiced during each plant outage. The bobbin probe also is the essential component which consists of the whole ECT examination system, and provides a decisive data for the evaluation of tube integrity in compliance with acceptance criteria described in specific procedures. The selection of probe is especially important because the quality of acquired ECT data is determined by the probe design characteristics, such as geometry and operation frequency, and has an important effect on examination results. The Electric Power Research Institute (EPRI) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. Flawed tube removed from operation, or artificial flaw is required for the original ...
The bobbin probe technique is basically one of the important ECT methods for the steam generator tube integrity assessment that is practiced during each plant outage. The bobbin probe also is the essential component which consists of the whole ECT examination system, and provides a decisive data for the evaluation of tube integrity in compliance with acceptance criteria described in specific procedures. The selection of probe is especially important because the quality of acquired ECT data is determined by the probe design characteristics, such as geometry and operation frequency, and has an important effect on examination results. The Electric Power Research Institute (EPRI) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. Flawed tube removed from operation, or artificial flaw is required for the original ...
...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION QUALIFICATION AND CERTIFICATION OF LOCOMOTIVE ENGINEERS Dispute Resolution Procedures ยง 240.405 Processing qualification review petitions. (a)...
Objective: Analyse the difference in school careers and secondary school qualification levels between unilateral hearing aid users and bilateral hearing aid users. Study design: Retrospective questionnaire study. Setting: Postal-based questionnaire. Participants: Names of adults known to have been fitted with unilateral or bilateral hearing aids during childhood were retrieved. This resulted in 292 names. Participants were selected using the following criteria: availability of the medical record, presence of bilateral hearing loss, completed secondary school education, normal IQ and a minimum aided word-recognition score of 70% at 10 years of age. The questionnaire was sent to 50 potential participants of whom 40 responded, resulting in two groups comprising 19 unilateral and 21 bilateral ...
International Thermonuclear Experimental Reactor (ITER) project is the international collaboration one for the commercialization of nuclear fusion energy through the technical and engineering verification. In ITER project, we plan to procure the blanket systems which has the risk of technology and cost when it is newly developed. We are developing the manufacturing process and joining technology for the ITER blanket to complete the procurement with qualified blanket system. To evaluate the soundness of manufacturing process, specimen and mock-up tests are being prepared. Finally, we can obtain the key technology of nuclear fusion reactor especially on the blanket design, joining and manufacturing technology through the present project and these technologies will help the construction of Korea fusion DEMO reactor and the development of commercial nuclear fusion reactor in Korea. In 1st year, through the fabrication of the Cu/SS and Be/Cu joint ...
Two criteria, geologic stability and barrier effectiveness, form the basis of the Subseabed Disposal Program's site qualification plan to evaluate the ocean basins and identify those regions having characteristics most favorable for containment of radioactive waste. Stability criteria are used to define those regions least likely to be disturbed by tectonic forces or oceanographic changes during the lifetime of a waste repository. Barrier criteria define those lithologies most likely to form an effective barrier to the release of radionuclides. Two north Pacific regions and three north Atlantic regions (PAC I and II and ATL I, II, and III, respectively) have thus far been selected for further investigation based on the site qualification plan. The PAC I region, centered on the Shatsky Rise in the northwest Pacific, has been subdivided into areas and locations on the basis of an exhaustive review of data available ...
This paper shows how molecular theory paves the way for accelerated aging tests of safety-related equipment in nuclear power plants, as required by NRC qualification programs. Arrhenius' model, based on an equation, provides useful information regarding the extent of molecular change as a function of time and temperature. Critical to determining the aging characteristics and qualified life of organic materials is the activation energy concept, which is derived from information gathered when the molecular reaction of the material is documented over the entire life cycle. In accelerated-aging applications, the importance of the model lies in characterizing the chemical related reactions of materials. The problem with the Arrhenius approach is that, in generating a testing period of reasonable duration, a rather high test temperature must be selected which may lead to an added and unrelated environmental effect.
Focused ion beam (FIB) microscopes have become well-established in the semiconductor industry during the past decade, and are rapidly gaining attention in the field of materials science, both as a tool for producing site specific, parallel sided transmission electron microscope (TEM) specimens and as stand alone specimen preparation and imaging systems. FIB secondary electron imaging (SEI) of nickel-based alloys, such as commercially produced Alloy 600 (approximately Ni 15Cr 10Fe 0.5C), has been demonstrated to show a high degree of sensitivity to the presence of deformation in the alloy, and FIB secondary ion imaging (SII) is particularly useful for identifying the presence of grain boundary corrosion, as secondary ion yields from metallic specimens can increase by three orders of magnitude in the presence of oxygen. This 'oxygen enhanced yield', makes FIB SII ideal for detection of corrosion at grain boundaries down to ...
Prepared to make housing project managers, maintenance engineering staff, and designers and architects of HUD - assisted and HUD - insured housing projects and mobile home parks aware of their responsibilities under the Natural Gas Pipeline Safety Act, this handbook provides technical guidance for the reduction of gas leaks and the handling of gas leak incidents in residential areas. The hazards of natural gas, concern over gas safety in residential areas, applicable codes and standards, and sources of information and help are reviewed, along with maintenance and engineering considerations relating to gas pipe failures, the detection of gas leaks, appliance servicing, and pipe installation, repair, and replacement. Housing management considerations are also examined, with attention to recordkeeping and reporting, emergency contingency planning, tenant education, staff qualifications and training, and the development and use of a maintenance and operations manual. ...
The proper selection of materials of construction is necessary to provide process equipment with optimum performance and corrosion resistance. If properly chosen, the selected material should deteriorate at a uniform, predictable rate, which will allow for maintenance or replacement at scheduled intervals. This concept of risk assessment for predictive maintenance is a minimum requirement for proper materials selection. Materials selection is based on prior service history, field corrosion tests, pilot-plant tests, and laboratory bench-top tests--in that relative order of usefulness. Corrosion test methods are usually divided into two groups: laboratory and field (plant-site) tests. The main difference between the two is that field test specimens are exposed to actual process conditions will all of the variables involved, while laboratory tests are a simulation of field conditions, ...
The objective of the inspection qualification is to ensure that applied non-destructive methods (NDT) have the required performance. The approach of the qualification process is systematic and carefully documented and therefore some new requirements can be seen concerning the composition of the documentation. There are also new document types, that only application of the inspection qualification requires. The most important of these is the technical justification, that includes the documented evidences concerning the performance of the inspection system. This publication includes two reports: 'Compilation of the inspection procedure' and 'Essential/influential parameters in NDT qualification'. The former of these discusses the issues to be considered in an inspection procedure especially from the point of view of the mechanised ultrasonic testing. The later report ...
This report describes a comparison result of technical standards applied to instrumentation and control systems for nuclear power plants between in Korea and in Russia. Russia also has a state-run organization authorized to conduct approval, cancellation, and audit in use of nuclear facility or equipment. The Russian standards for nuclear instrumentation and control equipment are analogous with the Korean ones in the aspect of basic concepts and principles. However, there are some differences in document structure, design requirements, qualification test items, depth of contents between two standard systems. The biggest deviation exists in the standard documents for seismic qualification and electromagnetic interference qualification. Korean seismic qualification standard utilizing US approach, defines testing and qualification methods specifically and clearly. Russian standards ...
This experiment is carried out in the series of the investigation on the damage mechanism of carbon steel. In this paper, the damage situation is considered by structure observations. The test were carried out in 600degC-1200degC temperature range, in blowing an argon gas. The reagents are Na{sub 2}O, Na{sub 2}O{sub 2} and NaOH. From structure observations, the holes are observed on the surface of iron-base material in some test conditions. This result is indicated that the selective reaction occurs. The selective reaction is more obvious as the time exposed to the high temperature is longer. It is considered that the selective reaction occurs after the chemical reaction between iron-base material and sodium compound. The areas, in which Mn-concentration is higher, are observed in products on the surface of specimen. (author)
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 chemical vapor deposition, were candidates for use on various components, but the coatings did not pass the ...
The significant technical and industrial aspects which have led to main coolant line (MCL) materials selection are addressed from a long term experience and operational practice point of view. They are based on the Siemens/KWU developed basic material concept for its nuclear power plants. It considers the choice of appropriate materials, the evaluation and qualification of the materials and the materials manufacturer, the use of appropriate semi-finished products, the tailoring of material and semi-finished products to the specific requirements of the various systems, the application of adequate manufacturing processes and the proof of the requirements by specifying proper tests and examinations. The main systems are assigned to safety classes in accordance with their safety relevance. Summarizing the operation time of nuclear power plants with ferritic MCL equipped by Siemens/KWU, more than 200 years of operation experience exist and no ...
The oxidation of Cr(III) hydroxides, mixed Fe(III)-Cr(III) hydroxides, and specimens of spinel phases NiCr2O4 and Fe(Cr,Fe)2O4 have been investigated in alkaline suspensions under the action of air and pure oxygen (1-3 atm). The rate of reaction increases with increasing alkali concentration, temperature, and oxygen pressure. Pu(IV) fixed on chromium hydroxides is not oxidized by oxygen under these conditions but is retained in the precipitate.
This Maintenance Implementation plan has been developed for Pacific Northwest Laboratory's (PNL) Nuclear Facilities: 306W, 324, 325, 327 and 329NMF. It is based on a graded approach, self-assessment of the existing maintenance program(s) per the requirements specified by US Department of Energy (DOE) Order 4330.4A, Chapter II, Change {number sign}3. The results of this assessment were evaluated to determine needed improvements in PNL Craft Services' current maintenance program. The objective of this implementation plan is to provide baseline information for compliance to the DOE 4330.4A, and for needed improvements. The prime consideration in applying a graded approach to the Order has been to maintain safe and reliable operations, environmental compliance, safeguards and security, programmatic mission, facility preservation, and/or other facility-specific requirements. Using the results of the self-assessment, PNL has selected nine of the 18 ...
This Maintenance Implementation plan has been developed for Pacific Northwest Laboratory`s (PNL) Nuclear Facilities: 306W, 324, 325, 327 and 329NMF. It is based on a graded approach, self-assessment of the existing maintenance program(s) per the requirements specified by US Department of Energy (DOE) Order 4330.4A, Chapter II, Change {number_sign}3. The results of this assessment were evaluated to determine needed improvements in PNL Craft Services` current maintenance program. The objective of this implementation plan is to provide baseline information for compliance to the DOE 4330.4A, and for needed improvements. The prime consideration in applying a graded approach to the Order has been to maintain safe and reliable operations, environmental compliance, safeguards and security, programmatic mission, facility preservation, and/or other facility-specific requirements. Using the results of the self-assessment, PNL has selected nine of the 18 elements of the ...
The Dalia field is located 210 km north west of Luanda (Angola), about 140 km from shore in 1400 meter water-depth. It was the second major discovery out of 15 made in the block 17 operated by Total. The Dalia Umbilical, Flow lines and Risers EPCI Contract was awarded in 2003. The sea-line network to connect and control the 71 wells and 9 manifolds consist of the following: 40 km of insulated pipe in pipe (12 inches into 17 inches) production flow lines; 45 km of 12 inches water and gas injection lines; 6 off 1.7 km flexible water and gas injection risers; 8 off 1.65 km flexible Integrated Production Bundle (IPB) risers; 75 km of control umbilicals. The flow assurance and associated insulation requirement of the production transport system was one of the main challenges of the project. With a crude temperature of 45 deg C at the wellhead and the required minimum temperature of 35 deg C on arrival at the FPSO, this problem was complex. Understanding that, due to the Joule Thompson ...
...QUALIFICATION AND CERTIFICATION OF LOCOMOTIVE ENGINEERS Implementation of the Certification...operations and certifies locomotive engineers from a different railroad...designated supervisor of locomotive engineers or a certified train...
Data Qualification (DQ) is a formal, technical process whose objective is to affirm that experimental data are suitable for their intended use. Although it is not possible to develop a fixed recipe for the DQ process to cover all test situations, these general guidelines have been developed for the Nuclear Engineering Section to establish a framework for qualifying data from steady-state processing. These guidelines outline the role of the DQ team providing insight into the planning and conducting of the DQ process.
Buried silicon carbide (SiC) microstructures with lateral dimensions in the #mu#m range were formed by high-dose projection of 1.5 MeV C"2"+ ions in Si(100) at different doses and temperatures and subsequent annealing for 10 h at 1250 deg. C. Sections of individual SiC microstructures were prepared for cross-sectional transmission electron microscopy (TEM) analysis using a focused ion beam (FIB). Besides the possibility to select an individual microstructure, the FIB technique has the advantage of producing specimen foils of uniform thickness. Therefore, it was possible to map the carbon concentration of microstructures by energy filtered TEM (EFTEM) using the C_K absorption edge without the need of any sample thickness correction. Local overstoichiometric (>50%) carbon concentrations are shown to be correlated to the formation of an amorphous phase in the SiC and to significant swelling visible at the Si wafer surface 2 #mu#m above.
Electron-beam codeposition of the elements to form certain high critical temperature superconducting materials, in particular A-15 compounds, has proven to be very useful in research directed at understanding and improving their superconducting properties. This work has used the close control of three or more evaporant sources to reproducibly make specimens that permit studies across selected regions of composition and phase space. The effect of composition and phase, together with the temperature and rate of deposition, on the growth morphology and superconducting properties has been studied. The superconducting properties measured include the critical temperature, ac loss, critical current density, and tunnel junction characteristics. The particular compounds studied include Nb_3Sn, Nb_3Ge, and V_3Si.
AbstractBackground: A defective innate immune response may contribute to the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). Employing a global gene expression analysis, this study was aimed at identifying specifically regulated genes within the epithelial compartment in inflammatory bowel disease (IBD). Methods: The epithelial fraction of human ileal mucosa samples from surgical specimens was obtained by laser microdissection. Gene expression was examined by global expression profiling (n = 18, Affymetrix), quantitative reverse-transcription polymerase chain reaction (RT-PCR) (n = 35), immunoblot analysis (n = 9), and immunohistochemistry (n = 25). Results: Global expression profiling revealed a pronounced downregulation of the retinoic acid-inducible gene I (RIG-I) with...
With the aim of optimizing the nitriding process, experimental studies of the plasma nitriding of four selected steels were carried out, using a d.c. glow discharge. The process parameters were varied systematically. By means of transmission and scanning electron microscopy and X-ray diffraction, the microstructures, including the thicknesses of the compound zones and the diffusion zones of the nitrided steels, were obtained. Using cross-sectional samples and a micro-Vickers indenter, hardness depth profiles were also obtained. From the time and temperature dependences of the hardness profiles, effective diffusion constants and corresponding activation enthalpies were obtained. Furthermore, in an attempt to shed some light on the atomistic nitriding mechanisms, the glow discharges were studied by measuring energy spectra of the energetic ions hitting the cathode (the steel test specimens). It was shown that an increase of the mean energy of the ...
Statement of problem Because noble dental casting alloys for metal ceramic restorations have a wide range of mechanical properties, knowledge of these properties is needed for rational alloy selection in different clinical situations where cast metal restorations are indicated. Purpose The purpose of this study was to compare the mechanical properties and examine both the fracture and polished surfaces of 6 noble casting alloys that span many currently marketed systems. Five alloys were designed for metal ceramic restorations, and a sixth Type GPT has Type IV alloy for fixed prosthodontics (Maxigold KF) was included for comparison. Material and methods Specimens (n=6) meeting dimensional requirements for ISO Standards 9693 and 8891 were loaded to failure in tension using a universal testin...
Material degradation of pressure tubes, which are the most important components in CANDU fuel channel, can only be evaluated by removing and examining them(material surveillance). This study aimed at establishment of overall evaluation technology including the evaluation of the material degradation for the integrity of pressure tubes of Wolsung units. Material tests for pressure tubes were performed as follows; (1) Evaluation on life limiting factors of pressure tubes (2) Review on leak-before-break and integrity maintenance technology of pressure tubes (3) Survey on selection criteria for tubes to be inspected and on related regulations for material surveillance (4) Analysis of material surveillance test procedure (5) Basic examinations of Wolsung unit 1 pressure tube material(TEM, texture, chemical component etc) (6) Manufacture of test equipments and test (DHCV, hydriding, grip and tensile specimen etc). 23 figs, 6 tabs, 59 refs. (Author).
A urine leukocyte count of > or = 50/mm3 together with a bacterial count of > or = 10(5) colony-forming units (CFUs) per milliliter was used to define significant infection in 160 children with neurogenic bladder and evaluate the leukocyte and nitrite components of the Chemstrip 9 test. A Chemstrip 9 leukocyte reading of or = 500 leukocytes together with a positive nitrite reaction occurred in 18 children and had a sensitivity of 40% with a 100% positive predictive value for infection. Other combinations of Chemstrip 9 leukocyte and nitrite reactions were unhelpful or of uncertain value. Selection of up to three specimens from each patient increased the number of samples to 360 and provided general confirmation of the above conclusions. Nitrofurantoin may reduce the sensitivity of the nitrite strip reaction. PMID:8359003
To fulfill the President s Vision for Space Exploration - successful human and robotic missions between the Earth and other solar system bodies in order to explore their atmospheres and surfaces - NASA must reduce trip time, cost, and vehicle weight so that payload and scientific experiment capabilities are maximized. As a collaboration among NASA Centers, this project will generate products that will enable greater fidelity in mission/vehicle design trade studies, support risk reduction for material selections, assist in optimization of vehicle weights, and provide the material and process templates for development of human-rated qualification and certification Thermal Protection System (TPS) plans. Missions performing aerocapture, aerobraking, or direct aeroentry rely on technologies that reduce vehicle weight by minimizing the need for propellant. These missions use the destination planet s atmosphere to slow the spacecraft. Such mission ...
This report presents a view of and commentary on the current status of equipment qualification (EQ) in nuclear industries of the major western nations. The introductory chapters discuss the concepts of EQ, the elements of EQ process and highlight some of the key issues in EQ. A brief review of industry practices and some of the prevalent industrial standards is presented, followed by an overview of current regulatory positions in the USA, France, Germany and Sweden. A summary and commentary on the latest research findings on issues relating to accident simulation, to aging simulation and some special topics related to EQ, has been contributed by Franklin Research Centre of Philadelphia. The last part of the report deals with equipment qualification in Canada and gives recommendations on EQ for new plants as well as currently operational CANDU nuclear power plants.
Sandia National Laboratories has the qualification evaluation responsibility for the design of certain components intended for use in nuclear weapons. Specific techniques in assurance and assessment have been developed to provide the quality evidence that the software has been properly qualified for use. Qualification Evaluation is a process for assessing the suitability of either a process used to develop or manufacture the product, or the product itself The qualification process uses a team approach to evaluating a product or process, chaired by a Quality Assurance professional, with other members representing the design organization, the systems organization, and the production agency. Suitable for use implies that adequate and appropriate definition and documentation has been produced and formally released, adequate verification and validation activities have taken place to ensure proper operation, and the software ...
This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB milling ...
The development and improvement of materials plays a key role in energy technology, particularly in power plant technology, because materials are crucial to plant performance and power availability. This becomes particularly clear when one considers that modern power plants generate temperatures of up to 600 C and pressures of up to 230 bar in order to increase process efficiency, conserve resources and reduce CO{sub 2} emissions. Modern heat-resistant materials for power plant technology are customised materials which have been developed to meet the specific requirements of special applications. After the requirement profile has been determined the material is developed or optimised on the basis of previous experiences gained with materials in power plant technology. Basic heat-resistant materials are ferritic materials containing 9 to 12% Cr as well as additions of Mo, V, Nb and W, amongst other elements. Together with the thermomechanical processing, the last-named elements play an ...
An alternative to synthetic materials for use in solar pond liners is to select clayey soils as hydraulic barriers. This option reduces the cost of construction and the risk of contamination of subsoil and groundwater by hot brines. This paper deals with the physical, chemical and hydraulic properties of different soils tested mainly as compacted clay liners. The underdeveloped nations have the option to use this type of liner, but before doing so several tests are recommended, including those for soil and water composition, permeability, plasticity and X-ray diffraction analysis. In this investigation the following samples are analyzed: native clayey soils with illite, montmorillonite and halloysite, treated and non-treated bentonites in powder and granulated form, a mixture of zeolite and sodium bentonite, and industrial minerals composed largely of halloysite, kaolinite and attapulgite selected clays. Neutral salt aqueous solutions (NaCl and ...
Based on an multivariate statistical evaluation of binary and metric data relating to the soil cover of the European Community five regionally representative reference soils (EURO-Soils) have been identified for chemicals testing in the EC. The soil material sampled at representative localities in Italy, Greece, Great Britain, France and Germany was treated and prepared according to OECD Test Guideline 106 and analysed in detail. The homogenised specimens were subject to an EC-wide ring test to evaluate the feasibility of the modified guideline and to validate the physical-chemical amenability of the reference soils for sorption tests. The results proved the validity of the soils selected for assessing the potential behaviour of new chemicals in soil on the basis of a comparative evaluation of the individual test results obtained. In the light of this parametric assessment potential test soils were subsequently identified in the individual EC ...
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...
This report contains the study on the dynamic characteristics of Wolsung fuel rod and on the dynamic balancing of rotating machinery to evaluate the performance of nuclear reactor components. The study on the dynamic characteristics of Wolsung fuel rod wa...
...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION QUALIFICATION AND CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process ยง 240.109 General criteria for eligibility based on...
Proposals for use of Alloy 800 as a H.T.R. boiler material have prompted studies of its creep and high temperature fatigue properties in impure helium with comparative tests in air. In impure helium, as expected in a H.T.R., reactions of potential importance are selective oxidation (of chromium, aluminium and titanium) and possibly carburisation from carbon monoxide or methane. In air, general oxidation will occur, possibly accompanied by nitridation. The effects of these reactions will depend on specimen geometry and the nature of the deformation. Two important possibilities are: (i) that environment affects the structure and properties of a surface zone of material undegoing uniform deformation (this may modify creep rate and crack nucleation); and (ii) that environment affects behaviour of a small region (e.g. at the root of a notch or ahead of a crack) in a specimen undergoing non-uniform deformation (this will modify ...
Methods are discussed for optimization of organizational model of longwall mining. Operations at a working face, their duration, number of miners, miner qualifications are analyzed. The so-called method for allocation of heteregeneous resources is used. Using the method optimum organizational models of working faces are constructed. The models consider working conditions, coal output, personnel, miner qualifications, duration of various operations and of idletime, and safety regulations. A computer code developed by the author for optimizing organizational models of longwall mining is described. 9 refs.
Equipment Qualification technology for I and C system on nuclear grade have been approved with accurate and safe for verifying and validation. It contributes to acknowledge of reliability and to review of user approval. Also it did not completely satisfied the requirement of Russia, it can be satisfied by bit of modification on design. It is expected to support the export of safety PLC to nuclear power plant. Proven EQ technology is required on the further markets of nuclear. Therefore, comparison test with foreign country is necessary to support the mutual accreditation of EQ for export of domestic products.
An American Society of Mechanical Engineers task group on stainless steel weld materials was organized to determine the need for ferrite measurements of production welds required by the US Nuclear Regulatory Commission Regulatory Guide 1.31 (Rev. 1). The task group studied paired ferrite measurements (i.e., calculated and measured ferrite numbers (FNs) for the material qualifications versus measured ferrite numbers for corresponding production welds (PWs)). Our purpose was to compare delta-ferrite content as measured in the filler metal weld qualification pad with that in the resultant PW. Welds made predominantly by three common processes (submerged arc, shielded metal arc, and gas tungsten arc) were included in the study. Weld metals investigated included types 308, 308L, 316, and 316L stainless steel. An initial evaluation of the paired ferrite measurements was made by the task group, and specific conclusions and recommendations were made. ...
... affluent of the Lower Congo River. Specimens of Matadi and the Inkisi River (also Lower Congo) have ... affluent of the Lower Congo River. Specimens of Matadi and the Inkisi River (also Lower Congo) have ...
The physicochemical forms and partitioning of corrosion products released from stainless steel upon exposure to selected environmental conditions is the subject of this investigation. This report describes the influence of calcareous sediment on the rate of release and fate of corrosion products produced when neutron-activated stainless steel specimens were exposed to a Globigerina ooze taken from the Northeast Pacific Ocean. The calcareous ooze used in this study consists largely of planktonic formanifera tests and was found to be about 90% CaCO_3. The trace metal content of this sediment was typical of average deep-sea carbonate sediments, and the ratios of trace elements to Ti were not remarkably different from a coastal clayey silt or a Northeast Pacific pelagic red clay. Most (>80%) of the trace metals extracted by sequential chemical treatment were associated with reductant-soluble materials, i.e., amorphous Mn and Fe oxides, or were ...
In addition to ceramics, alloys such as tool steel and nickel- and iron-based superalloys are being considered for high temperature applications such as missile bearings and low heat rejection engines. Studies were made to lubricate a nickel-based superalloy at 500{degrees}C, by using a vaporized aryl phosphate ester, at a concentration of 0.1% in air. From deposition and wear studies it was found that it was impossible to form a good polymeric coating on the superalloy surface. Energy dispersive X-ray analyzer (EDXA) analysis showed that this was due to minute quantities of aluminum in the alloy segregating to the surface, upon being heated to 500{degrees}C, forming a passive oxide coating. It was necessary to activate the surface, in order to lubricate the material successfully. A method of activation by electrodepositing the surface with a layer of iron oxide was developed. Once activated, a good lubricous polymer was formed on the superalloy surface. Tests performed under dynamic ...
Lubricant additives have been known to affect rolling element bearing surface durability for many years. Tapered roller bearings were used in fatigue testing of lubricants formulated with gear oil type additive systems. These systems have sulfur- and phosphoruscontaining compounds used for gear protection as well as bearing lubrication. Several variations of a commercially available base additive formulation were tested having modified sulfur components. The variations represent a range of ''active'' extreme pressure (EP) chemistries. The bearing fatigue test results were compared with respect to EP formulation and test conditions. Inner ring near-surface material in selected test bearings was evaluated on two scales: the micrometer scale using optical metallography and the nanometer scale using transmission electron microscopy (TEM). Focused-ion beam (FIB) techniques were used for TEM specimen preparation. ...
A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling device causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system ...
Macroinvertebrate communities in Rietvlei nature reserve wetland area and their relationship with water quality were studied with the aim to evaluate their use as potential indicators of pollution. Sampling locations were selected to include outlets from swage effluent, agricultural and informal residential runoff. A large increase in nutrient concentrations was observed downstream from discharged treated sewage with an associated decrease in species richness. Bioassays performed included: Daphnia magna, Hydra attenuate, Lactuca sativa, Allium cepa and Pyxicephalus adspersus. The highest percentage of lethality response to a screen (100% concentration) of sampled wetland water by test specimens were observed at the point source input of the Hartbeespoort treated sewage plant. Data generated from the AUSRIVAS method and multitrophic level bioassays revealed the deterioration of the wetland possibly due to factors such as increasing urbanization, ...
For the recruitment, training and position qualification of the simulator instructors and feedback of training effect, the management approaches are formulated in 'The System for Simulator Training and Licensing Examination of Daya Bay Nuclear Power Station Operators'. The concrete requirements on the professional knowledge, work experience and foreign language ability of a simulator instructor are put forward. The process of instructor training is designed. The training items include the trainer training, pedagogy training, time management training, operation activities training during outage of unit, 'shadow' training and on-the-jot training on simulator courses. Job rotation is realized between simulator instructor and licensing personnel on site. New simulator instructor must pass the qualification identification. After a duration of 2 years, re-qualification has to be carried out. On the basis of the operator training ...
Proactive qualification is today an integral part of the development process for steam turbines used in steam and combined cycle power plants. By providing experimentally based `random` variables, such as the steam path efficiency and blading reliability, it makes a valuable contribution to the economic `random` variables of the power plant, e.g. the rate of return, as viewed by the customer. One of the areas in which proactive product and process qualification plays an important role is the development of LP steam paths. (orig.) [Deutsch] Die proaktive Qualifikation ist heute fester Bestandteil des Entwicklungsprozesses bei Dampfturbinen, die fuer den Einsatz in Dampf- und Kombikraftwerken bestimmt sind. Sie leistet mit Hilfe experimentell ermittelter `Zufalls`-Variablen, wie z.B. Wirkungsgrad der Fluten und Zuverlaessigkeit der Beschaufelungen, einen wertvollen Beitrag zu den fuer die Kunden wichtigen wirtschaftlichen `Zufalls`-Variablen des ...
Fracture toughness data of pre-cracked Charpy single-edge bend, SE(B), specimens are compared with those of standard compact, C(T), specimens in the upper shelf and ductile-to-brittle transition regimes. Charpy sized SE(B) specimens provide ductile fracture toughness data, which are compatible with those of standard C(T) specimens. Statistical methods such as the exponential curve fitting method (ECF), the engineering lower bound toughness method (ELB), and the Master Curve method (MC) are used to provide meaningful lower bound cleavage fracture toughness estimates from the toughness scatter of the Charpy sized SE(B) specimens in the ductile-to-brittle transition regime. In this regime, according to the ELB and MC methods, SE(B) specimens provide cleavage toughness data, which tend to be non-conservative compared to those of standard C(T) ...
Safety related equipment installed in Korean Nuclear Power Plants are required to perform a safety function during and after a seismic event. To accomplish this safety function, they must be seismically qualified in accordance with the intent and requirements of the USNRC Reg. Guide 1.100 Rev. 02 and IEEE Std. 344-1987. This paper defines and summarizes acceptable criteria and procedures, based on the Korean experience, for seismic qualification of purchased equipment to be installed in a nuclear power plant. As such the paper is intended to be a concise reference by equipment designers, architectural engineering company and plant owners in uniform implementation of commitments to nuclear regulatory agencies such as the USNRC or Korea Institute of Nuclear Safety (KINS) relating to adequacy of seismic Category 1 equipment. Thus, the paper provides the methodologies which can be used for qualifying equipment for safely related service in Nuclear Power Plants in a ...
Serum specimens obtained from a nationwide sample of parenteral drug abusers (PDAs) during the period 1971-72 had previously been screened for human immunodeficiency virus (HIV) antibodies. Some specimens...Full Text Available
Effect of the coverage of shot peening, the surface roughness and shot shape, etc. on the stress corrosion cracking (SCC) of Alloy 800 in alkaline solutions was studied. Alloy 800 specimens were cracked in boiling alkaline solutions at the potntial range of {minus} 100 to 0mV in the boiling 50%NaOH+0.3%SiO {sub 2} solution. U bend specimens were tested under the polarized condition at the controlled potential to 0mV, showing that shot peened specimens cracked more easily. Tests of specimens with the same hardness showed that specimens hardened by cold working showed the higher susceptivity than that of surface hardened specimens. In these connections, U bend specimens of higher shot peened coverage were cracked at conditions of 593K and 10%NaOH solution. O-ring specimens of smaller stress level did not show any cracks ...
One hundred fecal specimens obtained from patients with acute gastroenteritis were tested for rotavirus with nine commercial immunoassays to evaluate the sensitivity, specificity, predictive value,...Full Text Available
A nucleic acid extraction system that can handle small numbers of specimens with a short test turnaround time and short hands-on time is desirable for emergent testing. We performed a comparative validation...Full Text Available
Corneal biopsy specimens from 3 patients with Cogan's microcystic corneal dystrophy were examined by light and electron microscopy. Specimens were taken from corneas showing microcysts, geographic or...Full Text Available
We describe a decision support system to distinguish among hematology cases directly from microscopic specimens. The system uses an image database containing digitized specimens from normal...Full Text Available
Author.Field, laboratory and market studies are a must for proper evaluation of natural resources for the mineral industry of lebanon. Sites selectively convenient to the existing major Lebanese ceramics industry centered in the Beqa'a region, were investigated as to their geology, geography and economic character. The raw materials are shales, mud stones, siltstones and other argillaceous rocks of Jurassic to Cretaceous age coming from selective sites in south and central Lebanon. The finished products include wall, floor, roofing tiles, pipes, sanitary ware, pottery and brick specimens. Differential thermal analysis, scanning electron microscopy, firing and physico-chemical tests and analyses characterized the raw materials into two major groups: the suitable are siliceous argillaceous rocks and unsuitable calcareous argillaceous rocks. The suitable group is divided into two varieties. The first is dominantly a disordered ...
This report is a summary of the Steam Generator Group Project progress for 1985. Statistical analyses are presented of data from nondestructive examination (NDE) round robin tests that were performed on the Surry generator in 1984. In the first round robin, teams acquired and analyzed their own data on a selected 10% subset of tubes. In the second round robin, analysts from each participating team analyzed identical sets of data which were provided to them by the Project. Results from several examinations utilizing advanced/alternate NDE technologies including alternate eddy current probes and techniques, ultrasonics, and profilometry are also reported. Criteria are listed for selecting tube specimens that will be removed from the generator. A sampling plan based on these criteria is detailed graphically in the report. The initial steps that have been taken to carry out the plan are described; tooling fabricated for the ...
This report is a summary of the Steam Generator Group Project progress for 1985. Statistical analyses are presented of data from nondestructive examination (NDE) round robin tests that were performed on the Surry generator in 1984. In the first round robin, teams acquired and analyzed their own data on a selected 10% subset of tubes. In the second round robin, analysts from each participating team analyzed identical sets of data which were provided to them by the Project. Results from several examinations utilizing advanced/alternate NDE technologies including alternate eddy current probes and techniques, ultrasonics, and profilometry are also reported. Criteria are listed for selecting tube specimens that will be removed from the generator. A sampling plan based on these criteria is detailed graphically in the report. The initial steps that have been taken to carry out the plan are described; tooling fabricated for the ...
Describes general trends in the quality of rural education: equivalent rural and urban performance on national standardized tests and high school graduation rates but continuing rural deficits in college attendance and teacher qualifications. Discusses the below-average performance of southern rural schools, factors affecting rural students' college attendance, and the influence of changing labor markets. (SV)
The paper reviews the formation of minor actinides in light water and fast reactors, as well as the current status and recent improvements in the nuclear data for minor actinides, and compares recently evaluated data with experimental results. The paper also describes the qualification of nuclear data by post-irradiation analysis and integral measurements in fast critical assemblies. (author).
Certification as applied to existing computer codes includes the verification and validation process, placing the code in configuration control, establishing user qualification standards and training requirements. All software intended for use in critical calculations must be certified. This report is intended to fulfill the requirements for the certification of the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system built February, 1992, by W.S. Parks. These modules are used for burnup, cooling, separate, and edit calculations.
The AT and T Round Cell has recently become a viable alternative to the conventional, rectangular, lead acid storage batteries in Class 1E applications at US nuclear generating stations. This paper discusses the qualification of the Round Cell for nuclear generating stations, its principal design attributes, the types of Class 1E applications most suited for the Round Cell, and industry experience related to its installation and operation.
... Zahra-Kingrsquo;s practice utilizes a range of media including textiles, metal casting, glass, sound, film and photography. Qualifications English Major from BA (Social Science) 1991; BA(Visual Arts) 1991; Grad. Dip. (Fine Art - Printmaking) 1993; Candidate for MFA 2001; Ph.D 2005. School of Art Research Clusters Art and Environmental Sustainability Art, ...
In Hungary, legislation for nuclear power plants was developed at the end of the 1970s, among which is the quality assurance code for nuclear power plants. Hungarian practice is presented, including discussion of the requirements for quality assurance, qualification of the suppliers and inspection practices. The general requirements of quality assurance in the course of construction of a nuclear power plant are presented: quality assurance of technological equipment, fuel, electrical equipment, automatic instrumentations, building structures and technology.
This paper discusses the clean-up of an Idaho National Engineering Laboratory (INEL) site utilized for disposal of transuranic contaminated waste from 1954 until 1970. The author presents requirements of the environmental protection statutes that have generated quality assurance requirements in addition to those historically implemented as a part of facility design, construction and operation. A hierarchy of program guidance quality documentation and procedures is discussed. Data qualification and computer database management are identified as requirements.
The Waste Acceptance Preliminary Specifications (WAPS) require that the DWPF estimate the inventory of long-lived radionuclides present in the waste glass, and report the values in the Waste Form Qualification Report. In this report, conservative (biased high) estimates of the radionuclide inventory of glass produced from waste currently in the Tank Farm are provided. In most cases, these calculated values compare favorably with actual data. In those cases where the agreement is not good, the values reported here are conservative.
Stylized numerical models of the tooth are usually employed in qualification procedure related to Electronic Paramagnetic Resonance in long-term accidental contamination dose reconstruction. In this work a voxel model was developed from the microCT image data set of a human non contaminated molar tooth. A stylized model, reproducing the characteristics of the voxel model, was also created in order to investigate the level of accuracy that can be obtained in this kind of study.
Substantial damages at main components of steam turbines do not have to result inevitably in an exchange of the components concerned. Rather a preliminary or final repair is possible which also considers the cause of the damage. An important condition with the technically complex questions is an appropriate qualification and experience of all involved persons. The common task of operators, manufacturers and insurance companies is to preserve the balance from costs, expenditure of time and risk.
The High-Level Waste Storage Tank Farms/242-A Evaporator Standards/Requirements Document (S/RID) is contained in multiple volumes. This document (Volume 2) presents the standards and requirements for the following sections: Quality Assurance, Training and Qualification, Emergency Planning and Preparedness, and Construction.
This paper will review code and standard and the safety related features of major components of Monju: Components of the Reactor Coolant Boundary; Components of the Reactor Shurdown Systems; Components of the Decay Heat Removal Systems; Components of the Engineered Safety Features; Other Safety Related Components. Their relationship to the system or plant function is emphasized, in reviewing these components.
A cryostat is described that was developed for irradiating a number of small metal specimens with a high beamcurrent of heavy particles at liquid nitrogen temperature. The specimens, which are mounted on a block, are taken out of the cryostat after irradiation and subsequently annealed in a temperature bath. The progress of annealing is followed by measuring the change in electrical resistivity of the specimens in liquid helium. (auth)
Weld metal, base material and stainless steel overlay specimens for Charpy tests and static tensile tests were irradiated for a year in a power reactor of the Bohunice nuclear power plant in place of the evaluated surveillance specimens. The material of the specimens was identical with that of the WWER-440 reactor pressure vessels, and was exposed to a fluence of (1.2 - 4.5) x 10"2"3 m"-"2 (E > 0.5 MeV) at approximately 270 degC. Some of the irradiated as well as unirradiated specimens were subjected to regeneration annealing at 475 degC for 168 h. The behavior of the materials after irradiation and annealing was evaluated. (author). 33 tabs., 32 figs., 8 refs.
A test program was conducted under contract to Sandia National Laboratories to investigate water/steam effects on elevated temperature low cycle fatigue and creep-fatigue of Alloy 800. This report presents interpretation and analysis of the test results. Tubular specimens with water sealed inside were cycled to failure under strain control. Tests were conducted to 616K (650/sup 0/F) and 922K (1200/sup 0/F); some at 922K included tensile or compressive hold periods to simulate creep-fatigue conditions. The tubular specimens showed significantly lower lives than solid bar specimens cycled at equivalent strain ranges. Rough internal surfaces contributed to early crack initiation with these specimens. Inclusion of hold periods caused further large reductions in cycles to failure.
The ductile-brittle transition behavior of neutron-irradiated welded A533B C1.1 steel has been studied by means of small specimen test technique for discussing the specimen size effects on the impact properties. Standard size, one-third size and 1.5 mm size Charpy V-notch specimens were prepared. Neutron irradiation was performed in JMTR with fluencies up to 0.75 and 1.3x10"2"4 n/m"2 (E > 1 MeV). Normalization of the USE is done by a curve fitting method and the USE of different size of specimens can be expressed by the equation; E=a x B"n, where a is a constant and n is an exponent. There observed linear relationships between DBTTs obtained using standard and sub-sized specimens. (author)
Blow forming characteristics of 5083 Al alloy and AZ31 Mg alloy recycled by solid state recycling were investigated. Scraps with different volume were recycled by hot extrusion and hot rolling in air. Oxide layers, which were contaminants from scrap surface, were distributed parallel to the extrusion direction in the recycled specimens. In the blow-forming test, the specimen from smaller scraps exhibited lower formability. The oxygen concentration in the recycled specimens was approximately proportional to the total surface area of scraps in the recycled specimen per unit volume. The low formability of the recycled specimens is likely to be attributed to contamination level of oxide. (orig.)
To investigate the dependence of the local texture of parts of an YBaCuO specimen on the distance of the seed crystal from the position of the part of the specimen, a very good textured YBaCuO specimen was cut into 9 rectangular pieces and into 12 boundary pieces of the cylindric original specimen. From the individual parts of the YBaCuO specimen the texture was measured by neutron diffraction at the Geesthacht reactor with an equal area raster. The grid width was 1 up to 10 deviation from the cylinder axis of the original YBaCuO cylinder and 2 from 10 deviation until 20 deviation. From the sum of the counted neutrons on small circles on the pole sphere the individual values of the distributions of the angular deviations of the c-axes of the crystalline domains from the cylinder axis have been calculated. The mean deviation of the c-axes from the axis of the original cylinder ...
Constant pull rate tests were conducted on tensile specimens of Inconel Alloy 600, Incoloy Alloy 800, and Type 304 stainless steel in deaerated 10% NaOH solution at 288 C (550 F) with a cover gas of 5% H_2 in N_2. The pull rate used for most experiments was 3.3 x 10"-"6 cm/s, which corresponds to an initial strain rate of 3 x 10"-"6 s"-"1. The electrical potential of the specimens was controlled by a potentiostat using a nickel wire as a hydrogen reference electrode. Under open circuit conditions, Type 304 stainless steel specimens cracked rapidly, but Alloys 600 and 800 specimens exhibited only ductile fracture. However, cracks readily formed in Alloy 800 specimens at potentials in the +50 to +300 mV range and in Alloy 600 specimens at potentials in the +150 to +250 mV range. Scanning electron microscope (SEM) photographs of some of the cracked ...
The organization of the Biofuels Excellence Network, inside PROMINP - the Program of Mobilization of the National Industry of Oil and Natural Gas, has the objective of improving the actions of technical innovation and management in the chain of Oil, Gas Natural and Biofuels, through the optimized use of physical, financial, technological resources, of information and staff, with maximum qualification in areas of the human knowledge, whose purpose is to make decisions on specific problems of improvement of processes and/or products, besides promoting actions for the development and reinforcement of the markets of ethanol and biodiesel. The organization of the Biofuels Excellence Network became necessary, in order to enable Brazil to reach vanguard standards in biofuels (ethanol and biodiesel) in a sustainable, competitive and environmentally responsible way. Among the main reasons for the creation of the Biofuels Excellence Network are: to speed up the acquisition ...
Heat exchangers for high and ultrahigh temperatures are a need and a precondition to realise high efficient fossil fired power plants based on the so-called Externally Fired Combined Cycle (EFCC) or the Indirect Fired Gas Turbines (IFGT). The main target of both processes is to increase the thermal efficiency of existing power plants by approximately 25% resulting in the same decrease in fuel consumption and, therefore, in the same reduction of CO{sub 2} formation. The main activities of the MPA University of Stuttgart in this project is focused on the characterisation and qualification of the structural material of the ultrahigh temperature heat exchanger (UHTHE) necessary in the above mentioned processes. The influence of the temperature and load on the material behaviour have been analysed by means of tensile tests and creep tests. The effectiveness of different coating systems and the interaction between coating system and basic material was also investigated. ...
LOCA (Loss of coolant accident) resistant heat-shrinkable polymeric products are widely used for the connection of LV cables for class 1E systems inside the containment area of nuclear power plants. The paper/presentation describes the verification of a reformulated compound for these products, where certain components of the compound formulation had to be substituted. A qualification programme with this so-called reformulated compound was undertaken to proof the equivalency of the products to the products made out of the original compound. The basic elements of this requalification project were material qualification tests including accelerated aging tests according to the arrhenius method and type tests in accordance to IEEE 383, including flammability tests. The test results showed that the products made out of the reformulated compound were similar in fit, form and function to the original products. Additional tests have also proven higher ...
The influence of material configuration and impact parameters on the damage tolerance characteristics of sandwich composites comprised of carbon-epoxy woven fabric facesheets and Nomex honeycomb cores was investigated using empirically based response surfaces. A series of carefully selected tests were used to isolate the coupled influence of various combinations of the number of facesheet plies, core density, core thickness, impact energy, impactor diameter, and impact velocity on the damage formation and residual strength degradation due to normal impact. The ranges of selected material parameters were typical of those found in common aircraft applications. The diameter of the planar damage area associated with Through Transmission Ultrasonic C-scan measurements and the peak residual facesheet indentation depth were used to describe the extent of internal and detectable surface damage, respectively. Standard analysis of variance techniques ...
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 with specific requirements (CTE and wettability suitable for ...
This study identifies potential applications and design requirements for ceramic materials (CMs) and ceramic composite materials (CCMs) in the NGNP hightemperature gas-cooled reactor (HTGR) primary circuit. Components anticipated for fabrication from non-graphite CMs and CCMs are identified along with recommended normal and off-normal operating conditions. The evaluation defines required dimensions and material properties of the candidate materials for normal operating conditions (NOC), anticipated transients, abnormal events, and design basis events. The report also identifies additional activities required for codifying the selected materials. The activities include ASTM Standard and ASME Code development and other work to support NRC licensing of the plant. Evaluation of the NGNP baseline design indicates components requiring either CMs or CCMs depend upon the reactor operating temperatures. For a reactor outlet temperature of 900 oC, four of the five evaluated ...
Twenty autopsy cases with 2009 pandemic influenza A (2009 H1N1) virus infection, performed between August 2009 and February 2010, were histopathologically analyzed. Hematoxylin-eosin staining, immunohistochemistry for type A influenza nucleoprotein antigen, and real-time reverse transcription-PCR assay for viral RNA were performed on formalin-fixed and paraffin-embedded specimens. In addition, the D222G amino acid substitution in influenza virus hemagglutinin, which binds to specific cell receptors, was analyzed in formalin-fixed and paraffin-embedded trachea and lung sections by direct sequencing of PCR-amplified products. There were several histopathological patterns in the lung according to the most remarkable findings in each case: acute diffuse alveolar damage (DAD) with a hyaline membrane (four cases), organized DAD (one case), acute massive intra-alveolar edema with variable degrees of hemorrhage (three cases), neutrophilic bronchopneumonia (five cases) and ...
To heighten durability and safety of materials/parts for undersea oil drilling, the development of ceramic base materials was made by developing function harmony type process technology which harmonizes on a high grade contrary characteristics and various functions. The paper summed up the fiscal 1997 results. In the design of system formation, computational simulation technology was developed to the composite process and the diploid system. The development of multifunction simultaneous manifestation materials was trially made by the higher nano structure process. A study was made of control of microstructures of porous materials and matrix filling by the gas phase precipitation control. Proposed were selective control of grain growth from species crystals and the columnar particle orientation laminated structure of simultaneous manifestation of strength and toughness. By composite precipitation reaction control, studied were simultaneous dispersion of whisker and ...
The use of the focused ion beam (FIB) systems has increased to a high level in recent years. The imaging, milling, and deposition capabilities of the FIB make it the ideal instrument for e.g., site-specific failure analysis, specimen preparation and nano-machining. Ion channelling contrast allows for selective imaging of polycrystalline and polyphase microstructures. In addition, the FIB and CrossBeam registered instruments are unique stand-alone analytical tools. Their vast capabilities have enabled numerous applications into the semiconductor and materials sciences applications. These integrated CrossBeam registered Tools enable the observation and direct control of the FIB operation in real time. In addition to the improved accuracy and resolution the electron beam adds analytical capabilities as STEM, EDS and EBSP to the instruments. To ensure a safe and reliable operation of the instrument, a dedicated vacuum system is needed. This type of ...
A new metastable beta titanium alloy, Beta-CEZ, has been developed by CEZUS. This alloy was designed for use at moderate temperatures up to 450 C (840 F). Alloy requirements also included high mechanical strength, high fracture toughness and improved creep resistance as compared to existing beta alloys. The understanding of the relationships between processing/microstructure/mechanical properties in the alloy may lead to applications of such promising material in current and future airplanes. In this study, a combination of several forging routes, which included through-transus, hot-die and warm-die forging, with subsequent heat treatments were selected in order to evaluate the microstructure-mechanical property relationships. It was found that the recrystallized prior beta grain boundary alpha, characteristic of the through-transus forging process, lead to an improved tensile-fracture toughness balance. The size of the primary alpha structure observed in ...
From January 2008 to December 2009, 433 Streptococcus pneumoniae strains were examined to determine the serotype distribution and susceptibility to selected antibiotics. About 50% of them were invasive isolates. The strains were isolated from patients of all age groups and 33.55% were isolated from children below 5 years. The majority was isolated from blood (48.53%) and other sterile specimens (6.30%). Community acquired pneumonia (41.70%) is the most common diagnosis followed by sepsis (9.54%). Serotyping was done using Pneumotest Plus-Kit and antibiotic susceptibility pattern was determined by modified Kirby-Bauer disk diffusion method and measurement of minimum inhibitory concentration (MIC) using E-test strip. Ten most common serotypes were 19F (15.02%), 6B (10.62%), 19A (6.93%), 14 (6.70%), 1 (5.08%), 6A (5.08%), 23F (4.85%), 18C (3.93%), 3 (2.08%) and 5 (1.85%). Penicillin MIC ranged between ? 0.012-4 ?g/ml with MIC?? of 1 ?g/ml. ...
A precise admixtures system is needed when using high-volume fly ash concrete as fresh concrete occasionally undergoes rapid slump loss after mixing, which can cause problems with casting, pumping and finishing of the concrete in hot weather. This paper provided details of a study conducted to implement high-volume fly ash concrete technology in India. Different families of admixtures were investigated to determine their water reduction capacities. A set-retarding admixture was used in some of the concrete mixtures in order to determine its efficacy. An Indian Portland cement was used to create a total of 22 different concrete mixtures. Four different fly ashes were used to replace portions of the concrete. The slump of the fresh concrete mixture was monitored for 2 to 3 hours. Unit weight and temperature of the concrete was measured. Specimens were cast in steel moulds in order to determine the compressive strength and unit weight of the hardened concrete. The ...
Full text of publication follows: Low activation ferritic/martensitic steels are receiving a high priority in the European long term materials research. Although extensively investigated, the available experimental data do not cover all required parameter ranges and cannot unambiguously be used to produce hardening/embrittlement trend curves. Therefore, the main objective of this work is to provide a physically-based engineering model offering a rational to experimental observations. From the literature, experimental data were selected to establish a database that mainly consists of 8 to 9Cr-steels irradiated in the range of 50 to 600 deg. C up to 30 dpa and with a He-content up to 5000 appm. The database includes neutron and proton irradiations, He-implanted as well as B- and Ni-doped steels. Because of the difficulty of interpretation inherent to the Charpy impact test, only tensile data were considered. The difficulty stems from the large range of ...
Over the last decade techniques such as confocal light microscopy, in combination with fluorescent labelling, have helped biologists and life scientists to study biological architectures at tissue and cell level in great detail. Meanwhile, obtaining information at very small length scales is possible with the combination of sample preparation techniques and transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM). Scanning electron microscopy (SEM) is well known for the determination of surface characteristics and morphology. However, the desire to understand the three dimensional relationships of meso-scale hierarchies has led to the development of advanced microscopy techniques, to give a further complementary approach. A focused ion beam (FIB) can be used as a nano-scalpel and hence allows us to reveal internal microstructure in a site-specific manner. Whilst FIB instruments have been used to study and verify the three-dimensional architecture of ...
The Waste Acceptance Preliminary Specifications (WAPS) require that the DWPF estimate the inventory of long-lived radionuclides present in the waste glass, and report the values in the Waste Form Qualification Report. In this report, conservative (biased high) estimates of the radionuclide inventory of glass produced from waste currently in the Tank Farm are provided. In most cases, these calculated values compare favorably with actual data. In those cases where the agreement is not good, the values reported here are conservative.
Preliminary results of studies into penetrant testing at high surface temperature (up to 200 deg.C), are presented. Tests were performed to assess the effectiveness of red dye penetrants using Al and NiCr samples containing artificial as well as natural discontinuities. The test results will be used in due course to formulate a specification for non-destructive testing procedure qualification at non-standard (i.e. outside 16-52 deg.C) temperatures.
The paper is devoted to analysis of Russian nuclear education system: its current status, specific features, difficulties and prospects. Russian higher education system in nuclear engineering has been created simultaneously with the development of nuclear industry, and the system completely satisfied all industrial demands for the specialists of different qualification levels. For the past several decades, nuclear education has lost its attractiveness to young people. The paper discusses the actions to be undertaken for reversing the situation. The paper underlines particularly the special role of international collaboration and all-European integration of nuclear educational programmes for further development of nuclear education all over the world. (author)
This paper discusses the remote plugging of leaks in inaccessible pipework, with main reference to small leaks which frequently appear in ancillary cooling water circuits of nuclear reactors. Initially developed to cure problems of the pre-stressed concrete pressure vessels of UK reactors, the ZORIC sealant has been used to repair leaking biological shield pipework on six CANDU reactors. ZORIC is based on a water-soluble epoxy resin and an aqueous suspension of a refined mineral clay. This paper describes the evolution of the sealant, the qualification and testing program, and their application to CANDU reactor systems. 2 refs., 6 figs.
Long-term aging of organic materials in reactor containment buildings has become a major issue within the nuclear community. In this article, the status of radiation-aging qualification test requirements in several countries is reviewed, and problems with the current aging methodologies are described. These problems include dose-rate and synergistic effects and environmental synergisms, which have been found for many different polymeric materials. A number of approaches to improved accelerated-radiation-aging tests for prediction of long-term aging behavior are discussed together with their limitations.
Long-term aging of organic materials in reactor containment buildings has become a major issue within the nuclear community. In this article, the status of radiation-aging qualification test requirements in several countries is reviewed, and problems with the current aging methodologies are described. These problems include dose-rate and synergistic effects and environmental synergisms, which have been found for many different polymeric materials. A number of approaches to improved accelerated-radiation-aging tests for prediction of long-term aging behavior are discussed together with their limitations.
The use of the ratio of the characteristic intensity to the continuum background intensity (P/B ratio) of the X-ray spectrum for a quantitative ion microprobe (IMP) or PIXE (particle induced X-ray emission) analysis of thin biological specimens was proposed previously. The IMP analysis of thick biological specimens is also of considerable practical use. In this paper, the possibility of using the P/B ratio to quantify minor elements in thick biological specimens is investigated. The epoxy resin based standards with gradual concentrations of KCNS up to 0.6 mol/kg and NBS bovine liver were analyzed by a 27 MeV {alpha} particle microprobe. The measured peak to background ratios (between 4.4 to 5.7 keV) agreed well with the theoretical calculations. The calculations showed that the concentration dependence of the P/B ratios was determined mainly by the absorption of X-rays in specimens. The results indicate ...
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 pores, the ...
Notched and smooth cylindrical plasma nitrided (PN) and quench and tempered (Q and T) steel specimens made of a B-Mn SS2131 ({approx}AISI 15B21H) steel have been exposed to constant amplitude plane reversed bending corrosion fatigue tests (R = -1) at 47 Hz in sea water. S - N curves show that sea water suppresses the fatigue limit and reduces fatigue strength (especially at long lives) of smooth and notched Q and T and PN specimens. Plasma nitriding improves the corrosion fatigue resistance of Q and T specimens; this is associated with the good corrosion resistance of {epsilon} and {gamma}`-phases, the enhancement of corrosion and fatigue by compressive residual stresses, and the consumption of H{sup +} ions during reduction of nitrogen. This improvement is more significant for smooth specimens and for long lives. Notch sensitivity of Q and T and PN specimens decreases with fatigue ...
Materials Scientists need information on the kinetics of the microstructural evolution processes that determine the finished microstructure, and hence the properties, of any material. E.g. recrystallisation, grain growth and phase changes. Such kinetic information requires reliable discrimination of differently oriented crystallites and/or different crystal phases coupled with useful spatial resolution and temporal resolution (i.e. high frame rates). These imaging results must be realised from a hot and changing specimen, in an instrument that is compatible with that hot specimen and with a practical specimen heater. Focused Ion Beams (FIB) offer strong contrast between crystallites and phases, and hence offer the ability to discriminate between these features even while imaging at fast frame rates, however their compatibility with hot specimens was unproven. Here we report results from a novel ...
Integrating technology readiness levels (TRL) into the management of engineering projects is critical to the mitigation of risk and improved customer/supplier communications. TRLs provide a common framework and language with which consistent comparisons of different technologies and approaches can be made. At Sandia National Laboratories, where technologies are developed, integrated and deployed into high consequence systems, the use of TRLs may be transformational. They are technology independent and span the full range of technology development including scientific and applied research, identification of customer requirements, modeling and simulation, identification of environments, testing and integration. With this report, we provide a reference set of definitions for TRLs and a brief history of TRLs at Sandia National Laboratories. We then propose and describe two approaches that may be used to integrate TRLs into the NW SMU business practices. In the first approach, we analyze ...
The Radiation Technology Center from IPEN-CNEN/SP, Brazil, developed a revolutionary design and national technology, a small-sized continuous run and multipurpose industrial gamma irradiator, to be used as a demonstration facility for manufacturers and contract service companies, which need economical and logistical in-house irradiation system alternatives. Also, to be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and potential users on process validation, training and qualification of operators and radioprotection officers. The developed technology for this facility consists of a continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m"2 of floor area, the ...
Accelerated aging tests have been conducted to evaluate the long-term durability of cementitious material against aggressive ions. In tests, cementitious specimens were immersed in the solutions containing concentrated aggressive ions at high temperature and it promoted diffusion of the ions in the specimen. This method would be suitable for the evaluation on the aging as the alteration of the specimen would be expected to resemble the natural behavior. This paper presents a classification of alteration mechanism in the immersion tests using MgCl{sub 2} and Na{sub 2}SO{sub 4} solution. This classification was done by relating the changes of compressive strength to microscopic and mineralogical changes.
The decontamination of the dissolution tank from spent fuel reprocessing out-ling device is studied, by using FL-AP decontamination agent. The decontamination factor per step is 2.2, 2.4, respectively for #alpha#, #beta# activities. After dissecting the tank, residual contamination in inner surface of the tank was found to be non-uniform. The exact original contamination value of the tank surface could be approximated by calculating the total amounts of radionuclide distributed on the hanging specimens, the dissecting specimen, and radioactive level in waste decontamination agent. Therefore, it can be concluded that the hanging specimens method is feasible for measuring the decontamination factor of spent fuel dissolution tank. (authors)
The single specimen unloading compliance technique has become the preferred method for evaluating J-integrals. It involves data acquisition and analysis using a computer. This paper describes in detail the development of a simple experimental system and related software that can be used in a laboratory equipped with a microcomputer and with access to a minicomputer. The effects of loading rate, test temperature, specimen geometry and material composition can be readily evaluated using this system. The results on a pressure vessel steel and an #alpha#-#beta# titanium alloy are discussed in Part II. (author).
... Congo. It is probable that the type locality Matadi is in error and is the location from ... specimens of this species have been collected between Matadi and Luozi. (click map to view...
A new technique has been developed for improving corrosion resistance on magnesium alloys. Specimens of AZ31 magnesium alloy were dipped into molten salt of NaBF{sub 4} at 723 K for various times, and then cooled, rinsed with water, and dried in air. Corrosion resistance in the surface treated specimens was evaluated by salt immersion test using 1% NaCl solution as a time for occurring filiform corrosion. On an un-treated AZ31 alloy, the time for starting the filiform corrosion was about 1.2 ks, while on the surface treated specimen, the time was prolonged into about 1300 ks. Moreover, the surface treated specimen showed corrosion resistance in low pH solutions, such as 1% HNO{sub 3} and HCl solutions. (orig.)
... Although cytologic evaluation of urine specimens is a standard Cesar Angeletti, MD ... 3. Rodriguez-Alonso A, Pita-Fernandez S, Gonzalez-Carrero J, ...
The paper discusses the aspects of repair and retrofitting technique adopted for a damaged reinforced concrete beam-column joint specimen under cyclic loading. A specimen designed based on Indian Standard specifications with consideration of seismic load but without adopting ductile detailing (NonDuctile) was investigated under reverse cyclic loading. Then, the damaged nonductile specimen was repaired with epoxy mortar and grouted using low viscous polymer, and retrofitted using fiber reinforced plastic (FRP) wrapping in beam and column components and steel plate jacketing in joint region. The experimental results showed that the retrofitted specimen not only regained its original strength and stiffness but also has overcome the deficiencies of nonductile detailing. The present study shows...
An effective rehabilitation strategy is proposed to enhance the strength and stiffness of the beam-column joint in this study. An analytical model is proposed to predict the column shear of the joints strengthened with carbon fiber reinforced polymer (CFRP). Three full scale interior beam-column joints, including two specimens strengthened with CFRP and one prototype specimen, are tested in this study. The specimens are designed to represent the pre-seismic code design construction in which there is no transverse reinforcement. A new optical non-contact technique, digital image correlation (DIC), which can measure the full strain field of specimen, is used to measure and observe the full strain field of the joint. The experimental results show that the beam-column joints strengthened with ...
BACKGROUND: An approach to the study of the pharmacokinetics of drugs in the lung is to measure their concentrations in bronchial biopsy specimens. The main criticism of this technique is that bronchial...Full Text Available
Type 304 stainless steel (SS) specimens sensitised at 873 K and 973 K for 1, 10 and 100 hours respectively were ion implanted using a 150 keV accelerator at an energy of 70 keV in two different doses of nitrogen namely 1 x 10"1"6 to 1 x 10"1"7 ions/cm"2. Ion implantation at 1 x 10"1"6 ions/cm"2 did not show any improvement in pitting resistance, however, the specimens implanted at 1 x 10"1"7 ions/cm"2 showed significant increase in pitting corrosion resistance when potentiodynamic anodic polarisation studies were carried out in acidic chloride medium. For specimens aged at 873 K, nitrogen ion implantation at 1 x 10"1"6 ions/cm"2 increased the intergranular corrosion susceptibility compared to that of unimplanted specimens. However, at the dose of 1 x 10"1"7 ions/cm"2, insignificant IGC attack was noticed. The IGC resistance increased with increase in the dose for all the specimens ...
In this work, a pre-cracked semi-circular shaped explosive simulant was loaded using a split Hopkinson pressure bar (SHPB). A high-speed camera was used to capture the deformation and fracture process of the specimen in situ. The digital images were processed using the digital image correlation (DIC) method. Next, full displacement and strain fields were obtained. The displacement vector field shows that the specimen fractured under tensile stress action. The strain field can be used to predict the crack propagation. Results show that the method of combined DIC and SHPB is effective to study the dynamic deformation and fracture behavior of explosive simulants. In addition, the specimen was loaded using a drop weight. The fracture toughness of the specimen was preliminary measured.
BackgroundSeveral fractal and non-fractal parameters have been considered for the quantitative assessment of the vascular architecture, using a variety of test specimens and of computational...Full Text Available
In this research, the interactive effect of grain and specimen sizes on the flow stress of sheet metal in microforming is investigated via the tensile test of pure copper and numerical modeling. Models based on different assumptions are proposed to analyze the size effect phenomenon. It is found that the flow stress decreases linearly with the decrease of the ratio of specimen to grain sizes. The grain boundary thickness decreases and its volume fraction increases with the decrease of grain size. The variation of grain boundary thickness is not proportional to the variation of grain size. Furthermore, the fraction of grain boundary increases with the strain and the ratio of specimen to grain sizes. Based on the FE simulation, it is found that the simulated flow stress, which is modeled bas...
In a prospective study, patients with the diagnosis of chronic ethmoid sinusitis were evaluated microbiologically by using biopsy specimens of the ethmoid sinus mucosa. Microbiology cultures were performed...Full Text Available
Wood polymer composite (WPC) specimens were produced by impregnating a tropical wood with methyl methacrylate and subsequently polymerised by ..gamma..-irradiation. Beam specimens of varying weight percentages of polymer were then subjected to a three point bend creep test under a constant load condition, for 250, 300 and 350 N. A Norton-Bailey (power law) mathematical model was used to describe the creep behavior, with the creep components determined by a nonlinear regression analysis. Significant creep improvements were obtained from the composite specimens as compared to the untreated wood specimens. Results indicated that maximum creep resistance is obtained when the amount of polymer loading exceeded 30%. An interfacial interaction between the polymer and the wood cell wall was used to account for the behavior of the increase in the creep resistance.
Off-axis electron holography is used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope (TEM) using focused ion beam (FIB) milling from the substrate side of the semiconductor device. The measured electrostatic potential is compared with results obtained from TEM specimens prepared using the more conventional 'trench' FIB geometry. The use of carbon coating to remove specimen charging effects, which result in electrostatic fringing fields outside 'trench' specimens, is demonstrated. Such fringing fields are not observed after milling from the substrate side of the device. Analysis of the measured holographic phase images suggests that the electrically inactive layer on the surface of each FIB-milled specimen typically has a thickness of 100 nm.
Outline: Discuss far-side weld problem and phased array techniques applied. Describe laboratory work on flawed piping specimens using L- and S-wave arrays and provide synopsis of results. Discuss conclusions ofr capability of phased array as applied to austenitic welds. Research Approach: Evaluate phased arrays on unifornly-welded piping specimens. Apply best methods to non-uniform welds. Correlate acoustic responses as function of weld microstructures.
The paper reports the recovery of zinc and cadmium following 6.1 MeV alpha particle irradiation at 4.2 K as studied by means of electrical reistivity measurements. Specimens of 10 #mu#m thick have been used in order to obtain a homogeneous defect distribution over the whole thickness of the specimen. The pre-irradiation resistivity ratios were 700 and 750 for cadmium and zinc, respectively. (Auth.).
Information is presented concerning the Materials Open Test Assembly (MOTA); instrumentation and control system; MOTA neutronic data; pressurized tube specimens; stress-rupture measurements for reactor materials; miniature specimen design; the Interim Examination and Maintenance (IEM) cell at the FFTF; support services; and general information concerning the FFTF.
A novel method for processing respiratory specimens to improve culture and acid-fast staining of mycobacteria is introduced. This new method utilized N,N-dimethyl-N-(n-octadecyl)-N-(3-carboxypropyl)ammonium...Full Text Available
Two accelerated aging test procedures are proposed for use on solid dielectric extruded distribution cables under wet conditions. One test method is a fixed time duration test in which the degree of cable specimen aging is assessed in terms of breakdown tests, while the other test method is a time to breakdown test in which the cable specimens are voltage stressed until failure ensues.
The procedure for field corrosion tests in sea water is decribed in DIN 50 917, Part II. Distinction is made thereby between long-term undisturbed test specimens, which remain at the exposure site up to the time of sampling, and disturbed test specimens, which are cleaned at certain time intervals for intermediate examination and subsequently exposed again. The comparability of results obtained with the two different types of test was to be investigated at the Helgoland test installation. At an exposure period of up to four years, undisturbed specimens of unalloyed and low-alloy steel grades feature considerably lower corrosion losses than disturbed specimens. At a longer exposure period of up to seven years, the corrosion rate can increase substantially again with the exposure time. This can be attributed to sulphate reduction in the anaerobic zone under the top coating. An effect of the alloying ...
Fifteen strains of CDC group 1 coryneform and biochemically similar bacteria were isolated from clinical specimens. Of the 15 strains isolated, 11 were derived from abscesses and purulent lesions, mostly...Full Text Available
In this paper the effect of adding commercially pure yttria concentrate and yttrium carbonate concentrate (NUCLEMON) on the densification of #beta#-Sialon has been studied. The specimens were sintered in graphite furnace at 1720 and 175 deg C, for 1 hour in a nitrogen atmosphere. Densities of up to 99% of the theoretical density were obtained. Microstructural analyses of the specimens were carried out with the aid of an X ray diffractometer and a scanning electron microscope. (author)
In order to investigate the relation between the pitting corrosion and precipitated carbides, the heat treatment of specimens was carried out in two ways: Solution treatment and carbides precipitation treatment. The experiment was focused on the polarization curves of specimens immersed in HCL solution and on the microscopic analysis of the corroded specimens through a potentiodynamic method. It was found out that the intergranular and pitting corrosion occurred remarkably in 0.1N and 1N KCL solution when carbides were precipitated around the grain boundary of the 304 stain steel. The intergranular corrosion was noticed in the region of passivation and the pitting was prominent in the region of passivation break-down. The distribution of pits on the solution treated 304 stainless steel was random, while that of pits on carbides precipitated specimen was concentrated around the grain boundary in 0.1N and ...
Taeniasis has been known as one of the prevalent parasitic infections in Korea. Until recently, Taenia saginata had long been considered a dominant, and widely distributed species but epidemiological profiles of human Taenia species in Korea still remain unclear. In order to better understand distribution patterns of human Taenia tapeworms in Korea, partial nucleotide sequences of mitochondrial cox1 and ITS2 (internal transcribed spacer 2) were determined, along with morphological examinations, on 68 Taenia specimens obtained from university museum collections deposited since 1935. Genomic DNA was extracted from formalin-preserved specimens. Phylogenetic relationships among the genotypes (cox1 haplotype) detected in this study were inferred using the neighbor-joining method as a tree building method. Morphological and genetic analyses identified 3 specimens as T. solium, 51 specimens as T. asiatica, and ...
Thinning specimens to electron transparency for electron microscopy analysis can be done by conventional (2-4 kV) argon ion milling or focused ion beam (FIB) lift-out techniques. Both these methods tend to leave 'mottling' visible on thin specimen areas, and this is believed to be surface damage caused by ion implantation and amorphisation. A low energy (250-500 V) Argon ion polish has been shown to greatly improve specimen quality for crystalline silicon samples. Here we investigate the preparation of technologically important materials for nanoanalysis using conventional and lift-out methods followed by a low energy polish in a GentleMill"T"M low energy ion mill. We use a low energy, low angle (6-8 deg.) ion beam to remove the surface damage from previous processing steps. We assess this method for the preparation of technologically important materials, such as steel, silicon and GaAs. For these materials the ability to ...
Solid recycling of AZ31 Mg alloy with vapor deposition coating layer of high purity Mg was evaluated. In the open die forging experiments, two AZ31 Mg alloy specimens with the pure Mg layer were sufficiently bonded by forging at 673 K. Furthermore, the Al and Zn of the AZ31 substrate diffused up to the center of the pure Mg layer. By the theoretical analysis, it is suggested that the grain boundary diffusion enhanced by grain refinement due to hot forging contributes to the solid state bonding of the specimens. Also, the solid recycled specimen was fabricated from the AZ31 Mg substrate with pure Mg layer by hot extrusion at 673 K. The solid recycled specimen showed almost the same tensile properties as the virgin extruded specimen. This is probably related not only to the grain boundary diffusion but also severe plastic deformation by hot extrusion. (orig.)
The metal dependence of mesoporous activated carbons with various metal acetylacetonate (acac) particles prepared from Morwell coal was studied. In experiment, the mixture of Morwell coal and acac metal complexes were dissipated into tetrahydrofuran, and after agitation in Ar atmosphere, the solvent was removed by vacuum distillation. Coal specimens with Fe(acac)3, Ni(acac)2 and Co(acac)2 as acac complexes were activated by exchanging flow gas with water vapor after heat treatment in N2 gas flow at 900{degree}C. The pore sizes of the specimens were obtained from N2 adsorption isotherms by BET method and BJH method. Conditions of pores and metals in the specimens were examined by XRD measurement and TEM observation. The relation between the above conditions and pore characteristics obtained from adsorption experiment was also examined. As a result, the difference in mesopore ratio between the specimens ...
Strain controlled fatigue experiments on the modified ferritic-martensitic 12% Cr-steel Manet have been performed during, after and without irradiation. Continuous push-pull cycling of the hollow fatigue specimens with a cycle ratio R=-1, an axial strain rate of 8.10{sup -4} s{sup -1} and total strain ranges {Delta}{epsilon}{sub t} between 0.42% and 1.0% has been applied in vacuum (5.10{sup -3} Pa) at T=250 C. For the irradiation, a 104 MeV {alpha}-particle beam was used. Compared to unirradiated specimens, in-beam specimens undergo irradiation hardening at an advanced fatigue/implantation stage. Post-irradiation specimens show significantly higher total stress amplitudes and reduced fatigue lives. TEM investigations of in-beam and post-irradiation specimens reveal helium bubbles with different diameters on internal surfaces and in the matrix. (orig.).
To investigate the effect of external loads arising from differential thermal expansion between a substrate and a surface-mount component during thermomechanical cycling, specimens with a nickel surface-mount component on a copper substrate were prepared. Specimens consisted of two 100 #mu#m thick 1 mm"2 solder joints about 9 mm apart, with two designs. In one specimen (denoted 'dual-shear'), the as-fabricated joints were not stressed due to differential contraction during solidification and cool down. In the other specimen (denoted 'component'), a continuous copper substrate between the joints caused the nickel component to be put in compression during cool down, which imposed shear on the joints. To impose differential thermal shear strains, the 'dual-shear' specimen was clamped to a copper block to cause a significant reversal in sign of the shear imposed on the solder joint ...
Artificial selection and experimental evolution document natural selection under controlled conditions. Collectively, these techniques are continuing to provide fresh and important insights into the...Full Text Available
The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fur Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The ...
The testing of candidate fuel elements at prototypic operating conditions with respect to temperature, power density, hydrogen coolant flow rate, etc., a crucial component in the development and qualification of nuclear rocket engines based on the Particle Bed Reactor (PBR), NERVA-derivative, and other concepts. Such testing may be performed at existing reactors, or at new facilities. A scoping study has been performed to assess the feasibility of testing PBR based fuel elements at the TREAT reactor. initial results suggest that full-scale PBR, elements could be tested at an average energy deposition of {approximately}60--80 MW-s/L in the current TREAT reactor. If the TREAT reactor was upgraded to include fuel elements with a higher temperature limit, average energy deposition of {approximately}100 MW/L may be achievable.
The two main aspects of the concept proposed by the ICRP in recommendation 26 for the radiation risk, the differentiation of stochastic and non stochastic damages and the qualification of the stochastic risk, are discussed in its consequences for radiation protection in X-ray diagnostics. Quantitative results from the literature serve to demonstrate the risk factors for the various organs and their sum concerning the position of the layer. As special points of somatic risk appeared the mamma and the pelvic region. The particular risk of CT examination is determined by number and position of the layers and the scan parameters of the system. For typical CT examination the resulting risk factors are estimated in comparison with conventional X-ray diagnostics. The somatic risk of CT examination is relatively high and comparable to conventional examination with the highest risk, while the genetic risk - as in conventional diagnostics - depends on the distance of the ...
The two main aspects of the concept proposed by the ICRP in recommendation 26 for the radiation risk, the differentiation of stochastic and non stochastic damages and the qualification of the stochastic risk, are discussed in its consequences for radiation protection in X-ray diagnostics. Quantitative results from the literature serve to demonstrate the risk factors for the various organs and their sum concerning the position of the layer. As special points of somatic risk appeared the mamma and the pelvic region. The particular risk of CT examination is determined by number and position of the layers and the scan parameters of the system. For typical CT examination the resulting risk factors are estimated in comparison with conventional X-ray diagnostics. The somatic risk of CT examination is relatively high and comparable to conventional examination with the highest risk, while the genetic risk - as in conventional diagnostics - depends on the distance of the ...
The two main aspects of the concept proposed by the ICRP in recommendation 26 for the radiation risk, the differentiation of stochastic and non stochastic damages and the qualification of the stochastic risk, are discussed in its consequences for radiation protection in X-ray diagnostics. Quantitative results from the literature serve to demonstrate the risk factors for the various organs and their sum concerning the position of the layer. As special points of somatic risk appeared the mamma and the pelvic region. The particular risk of CT examination is determined by number and position of the layers and the scan parameters of the system. For typical CT examination the resulting risk factors are estimated in comparison with conventional X-ray diagnostics. The somatic risk of CT examination is relatively high and comparable to conventional examination with the highest risk, while the genetic risk - as in conventional diagnostics - depends on the distance of the ...
The radiation hardening studies started in the mid decade 1960-1970. To survive the different military or space radiative environment, a new engineering science was born, to understand the degradation of electronics components. The different solutions to improve the electronic behavior in such environments have been named 'radiation hardening' of the technologies. Improvement of existing technologies, and qualification methods have been widely studied. However, on the other hand, specific technologies were developed: the Silicon On Insulator technologies for CMOS or Bipolar. The HSOI3HD technology offers today the highest hardening level for the integration density of hundreds of thousand transistors on the same silicon. Full complex systems could be produced on a single die with a technological radiation hardening and no more system hardening.
This paper is part of a study that assessed the level of commitment of primary schools of remote area dwellers (RADs) to basic education between October 2004 and April 2005. The research question focused on the level of commitment of schools to universal basic education, school-community partnership in school governance and parental involvement in the way the curriculum was delivered. Questionnaire and interviews were used. The results show a significant relationship between teachers' perceptions and variables such as district, qualifications, age, location, and experience. There is consistency between teachers' perceptions and children's academic performance. It has been found that learner achievement in RADs schools is low and that parents are not actively involved in their children's education due to the policy environment and school management practices.
The Hanford Waste Vitrification Plant Project has been established to convert the high-level radioactive waste associated with nuclear defense production at the Hanford Site into a waste form suitable for disposal in a deep geologic repository. The Hanford Waste Vitrification Plant will mix processed radioactive waste with borosilicate material, then heat the mixture to its melting point (vitrification) to forin a glass-like substance that traps the radionuclides in the glass matrix upon cooling. The Hanford Waste Vitrification Plant Quality Assurance Program has been established to support the mission of the Hanford Waste Vitrification Plant. This Quality Assurance Program Description has been written to document the Hanford Waste Vitrification Plant Quality Assurance Program.
Under 10CFR50 Appendix B, utilities have a commitment to establish and maintain material control programs to assure the safety and reliability of their power plants. The guidelines in this report discuss methods of establishing, maintaining, and extending the shelf life of limited life items. In addition, these guidelines establish justifiable shelf lives for a sample of 70 items and review the effects of environmental conditions. Moreover, the guidelines are consistent with utility qualification test documentation and provide for evaluation of items with expired shelf lives. These guidelines set precedent by indicating that the shelf life is greater than previously available for many items. This increase in shelf life has been established through natural and accelerated aging tests.
The RECH-1 MTR reactor has been converted from HEU to MEU (45% enrichment) and the decision to a LEU (20% enrichment) conversion was taken some years ago. This LEU conversion decision involved a local fuel development and fabrication based on U{sub 3}Si{sub 2}-Al dispersion fuel, and a fabrication qualification stage that resulted in four fuel elements fully complying with established fabrication standards for this type of fuel. This report-presents relevant points of these four leaders fuel elements fabrication, in particular a fuel plate core homogeneity control development. A summary of the intended in core follow-up studies for the leaders fuel elements is also presented here. (author)
An evaporative cooling system developed for operation and qualification testing of silicon pixel and microstrip detectors for the inner tracking detector of the CERN ATLAS spectrometer is described. Silicon detector substrates must be continuously operated between 0 and ???7?C in the high radiation environment near the circulating beams at the CERN Large Hadron Collider (LHC). This requirement imposes unusual constraints on the cooling system and has led to the choice of perfluoro-n-propane (C3F8) refrigerant, which combines good chemical stability under ionizing radiation with high dielectric strength and nonflammability. Since the silicon detectors must also be of extremely light construction to minimize undesirable physics background, coolant tubes are of thin (200 ?m) aluminum wall, wh...
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...
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 standards to rank them. The oxide phases formed on the surfaces of the non-coated ...
Most of previous study for creep rupture of RPV lower head under severe accident condition, have been focused on global failure of RPV lower head. In contract, the local failure of the RPV nozzle region has not been studied in detail. The existence and features of nozzle failure in LAVA-ICI specimen of KAERI and LHF-4 specimen of Sandia National Lab., are observed. It is confirmed that the nozzle failure of LHF-4 specimen is due to the hoop stress in the RPV. The tensile tests in various temperatures and the creep rupture tests in various temperatures and stresses, are accomplished. The finite element analysis for LAVA-ICI experiment was confirmed, and the stress and deformation analysis results are used in LAVA-ICI experiment. 17 refs., 34 figs., 3 tabs. (Author)
We have measured some of the optical characteristics of a novel energy conversion medium, over a range of compositions in the system Yb[sub 2]O[sub 3][minus]Al[sub 2]O[sub 3], which we have fabricated by a proprietary process. These specimens have good resistance to thermal shock, are durable, and are mechanically and chemically stable. The integrated emission of light generated by these unoptimized specimens when heated with a propane-air flame and detected with a silicon photodetector ranged up to 1.88 watts/cm[sup 2]. The emission spectrum from these specimens when heated with a propane-air flame and detected with a germanium photodetector shows a narrow band in the vicinity of 1 micron.
We conduct the static and dynamic loading fracture experiments on magnesium alloy (AZ31B) under the equitable and inequitable biaxial stress. We process specimens as cross type with cracks. There are different kinds of cracks defined by their crack angles. By using a hydraulic high-speed biaxial experiment machine, we put the equitable and inequitable stresses on the specimen. We analyze results using the caustic method. The experiments reveal a few important results. There is negative correlation between the fracture toughness value and the plate thickness in the magnesium alloy sheet specimen. The fracture toughness value decrease in the case the crack has the angle different from the loading direction. The fracture toughness value decreases significantly under the inequitable biaxial stress. (orig.)
A novel method to control the mixed-mode bending (MMB) specimen is presented. By maintaining a constant opening, or Mode 1, displacement rate, stable delamination growth is achieved for all mixed-mode ratios. A constant-opening displacement rate is achieved by attaching a second displacement transducer to the hinges of the specimen. The test machine is then controlled externally by the second displacement transducer. By achieving stable delamination growth and monitoring the opening displacement, an experimental compliance calibration may be derived for the Modes 1 and 2 parts. This new approach to control the test and determine the experimental compliance calibration, overcomes the potential inaccuracies of the previously used beam theory expressions to determine compliance and to separate the modal values of G.
We present a fully automated method for three-dimensional (3D) elemental analysis demonstrated using a ceramic sample of chemistry (Ca)MgTiO_x. The specimen is serially sectioned by a focused ion beam (FIB) microscope, and energy-dispersive X-ray spectrometry (EDXS) is used for elemental analysis of each cross-section created. A 3D elemental model is reconstructed from the stack of two-dimensional (2D) data. This work concentrates on issues arising from process automation, the large sample volume of approximately 17x17x10 #mu#m"3, and the insulating nature of the specimen. A new routine for post-acquisition data correction of different drift effects is demonstrated. Furthermore, it is shown that EDXS data may be erroneous for specimens containing voids, and that back-scattered electron images have to be used to correct for these errors.
BackgroundModern metal-on-metal hip resurfacing implants are being increasingly used for young and active patients, although the long-term outcome and failure mechanisms of these...Full Text Available
By isomorphous replacement of silicon by phosphorus the authors have synthesized crystalline aluminosilicophosphates with structures of the zeolites type A and faujasite. They determine the adsorption capacity of specimens treated at 575-1275/sup 0/K. They show that the thermal stability and acid resistance of aluminosilicophosphates depend on the quantity of phosphorus in their structure.
BackgroundPCR amplification for the detection of pathogens in biological material is generally considered a rapid and informative diagnostic technique. Invasive Salmonella...Full Text Available
Samples of longissimus and multifidi muscles at the thoracic and lumbar levels of the spine were examined histochemically on autopsy specimens from 21 adult male subjects (aged 22 to 46 years) and on...Full Text Available
The morphological appearance, incidence and prognostic significance of human chorionic gonadotrophin (HCG)-containing cells in seminomas were examined in a retrospective series of 228 orchidectomy specimens,...Full Text Available
Following studies on fiber and sheet texture of hexagonal crystal system in 1988, work has been extended to tube texture. Using the zircaloy-4 fuel cladding of Wolsung-type reactor as specimen, six pole figures for different crystallographic planes were m...
Change in structures of 3 kinds of coals with different coal ranks and their deashed coals was studied by heat treatment below 200{degree}C. In experiment, crushed Adaro, Taiheiyo and Huaibei coals below 200mesh and their deashed coals were used as specimens. The coal and deashed coal specimens dried in vacuum at 110{degree}C for 3 hours were filled into an autoclave, and the heat-treated coal specimens were prepared by holding them under initial nitrogen pressure of 2kg/cm{sup 2} at a fixed temperature for 30min. Extraction using pyridine as solvent, volumetric swelling using methanol or benzene as solvent, and measurement of the amount of carboxyl and phenolic hydroxyl functional groups were conducted for these coal specimens. The experimental results are as follows. Huaibei coal has developed aromatic ring structure, and its structure is hardly affected by heat treatment. The oxygen containing ...
Trichomonas vaginalis is an important pathogen in both men and women. Culture is considered the diagnostic gold standard, although studies have shown that PCR is more sensitive than...Full Text Available
Serratia odorifera biogroup 1 was isolated from the blood and urine of an alcoholic male with cirrhosis and signs of septic shock. The organism is rarely reported to occur in clinical specimens. This...Full Text Available
The polymerase chain reaction (PCR) was investigated as a means of diagnosing Mycoplasma pneumoniae infections. The target DNA sequence was a 375-bp segment of the P1 virulence protein. This DNA segment...Full Text Available
The relative sensitivities of different protocols for detecting cytomegalovirus nucleic acid sequences in histological specimens, using a biotinylated cDNA probe, were assessed. Several commonly used...Full Text Available
In the present study a partial replacement of aggregate with two different ratios of waste rubber (5%, 10%) with the addition of a constant ratio of rice husk ash (RHA), 5% was carried out. The hardened cement mortar used the optimum water of consistency. The specimens were molded into 1 inch cubic moulds .The specimens were first cured for 24 hours, at 100% relative humidity and then cured under tap water for 3, 7 and 28 days followed by irradiation at different doses of gamma irradiation namely 5 and 10 kGy. The physico-chemical and mechanical properties such as compressive strength, total porosity and bulk density were studied for the three types of specimens. The results showed that the values of the compressive strength, bulk density and chemically combined water of the blended cement mortar paste (OPC-RHA) increase ,while blended cement mortar paste with 5% RHA and 5, 10% waste rubber decrease. The results were ...
Full text: The focused ion beam (FIB) miller is becoming well established as a machine for the structural analysis of materials and for the rapid preparation of transmission electron microscope specimens. It has also been used for some time in the semiconducting materials industry for the analysis, repair and redesign of device materials. However, one emerging technique is the use of the FIB for micromachining. The FIB software can also be used to manufacture and machine components. This process can occur through converting software, typically in the form of bitmaps or TIF files, to proprietary 'stream' files. These files allow, often complex, patterns to be generated and milled into the specimen and thus the generation of micro-electromechanical systems. Frequently, this involves largely two-dimensional patterns and structures, however, more complex patterns and file types can be generated which allow, for example, device prototyping or the ...
The identification of crystallographic phases in the scanning electron microscope (SEM) has been limited by the lack of a simple way to obtain electron diffraction data of an unknown while observing the micro structure of the specimen. With the development of Charge Coupled Device (CCD) based detectors, backscattered electron Kikuchi patterns (BEKP), alternately referred to as electron backscattered diffraction patterns (EBSP), can be easily collected. Previously, BEKP has been limited to crystallographic orientation studies due to the poor pattern quality collected with video rate detector systems. With CCD detectors, a typical BEKP can now be acquired from a micron or sub-micron-sized crystal using an exposure time of 1-10 seconds with an accelerating voltage of 10-40 kV and a beam current as low as 0.1 nA. Crystallographic phase analysis using BEKP is unique in that the properly equipped SEM permits high magnification images, BEKP`s, and elemental information to ...
A Legionella-like organism (strain 1087-AZ-H) was isolated from a pleural-fluid specimen from a renal transplant patient undergoing immunosuppressive therapy. Growth characteristics and gas-liquid chromatography...Full Text Available
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
Rotazyme II, which is a shorter version of Rotazyme (less than 3 h), was compared with electron microscopy and Rotazyme for sensitivity and specificity on 229 human stool specimens. Compared with electron...Full Text Available
Endocervical swabs from 212 women and urethral swabs from 100 men were tested by the routine methods for McCoy cell culture and simultaneously by a novel enzyme amplified immunoassay test to detect...Full Text Available
Tissue microarray technology (TMA) is a relatively new approach for efficiently and economically assessing protein and gene expression across large ensembles of tissue specimens. Tissue microarray technology...Full Text Available
Dermal dendritic cells from eleven cases of mycosis fungoides (MF) (six patch and five plaque stage), two cases of pre-MF, and five specimens of normal human skin, were characterized immunohistochemically...Full Text Available
The newly developed techniques by the Hot Laboratory (JMTR HL) have provided for us the key information on behavior of specimens due to mechanical / physical / chemical / synergistic effects of radiation, stress and water for fission and fusion reactor environment. These techniques are focused on several topics as follows; (1) miniaturized specimen test for the development of fusion reactor materials, (2) slow strain rate tensile testing (SSRT) and crack propagation measuring tests for the study of Irradiation Assisted Stress Corrosion Cracking (IASCC) of core internals of LWR, (3) handling technique on specimens including tritium for the research and development of tritium breeders and neutron multiplier as fusion blanket materials, (4) joining method using the Tungsten Inert Gas (TIG) welding technique for re-assembling of capsule and re-fabrication of specimen and (5) nondestructive evaluation using ...
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 dark contrast. The bright contrast sublayers were amorphous ...
Internal pressure creep tests as well as uniaxial creep tests were conducted on 9Cr and 12Cr steels welded joints in order to evaluate creep strength of the high chromium steels welded parts under multiaxial stress conditions, where a welding direction of the internal pressure specimen was longitudinal one. Except under high stress conditions, cracks occurred at fine grained HAZ region for both materials, i.e., the type IV mode fracture. Regarding creep voids distribution along thickness direction of the internal pressure specimens, the creep voids were predominantly observed in the middle of the thickness at the HAZ region while they might be negligible in outer and inner surface of the specimen. Finite element analysis which considers HAZ and weld metal properties revealed that the principal stress (hoop stress) and the stress multiaxiality are the largest in the middle of the thickness at the HAZ region under the ...
Coryneform isolates from clinical specimens frequently cannot be identified by either reference laboratories or research laboratories. Many of these organisms are skin flora that belong to a large number...Full Text Available
Constant extension rate (CERT) tests were performed on Alloy 690 and Alloy 800 nuclear steam generator tubing specimens. For the Alloy 690 specimens, tests were performed in deaerated 10% sodium hydroxide solutions at 315 deg C with a +100 mV applied potential. For the Alloy 800 specimens, tests were performed in deaerated 5% sodium hydroxide solutions at 343 deg C with no applied potential. The test specimens were machined from tubing which was produced by different manufacturing processes and in different heat treated conditions. The Alloy 690 tubing was tested in six different thermomechanical conditions, while the Alloy 800 tubing was tested in four different thermomechanical conditions. The results from the test program include a complete microstructural examination using light-optical and scanning electron microscopy. The CERT test results (such as maximum stress achieved and crack morphology) are ...
When postpartum cervical biopsy specimens were compared with biopsy specimens from nonpregnant women, they revealed a 12-fold decrease in mechanical strength, a 50% reduction in the concentrations of collagen and sulfated glycosaminoglycans, a 35% reduction in hyaluronic acid, an increase in collagen extractability, and a fivefold increase in collagenolytic activity. Primiparas with relatively high concentrations of collagen and hyaluronic acid had relatively long cervical dilatation times during established labor, suggesting a physiologic importance to these variables. This correlation was not found in multiparas, even though the mean values of the biochemical parameters tested were similar to those in primiparas. Second-trimester biopsy specimens taken from patients with cervical incompetence contained normal collagen concentrations, but relatively high collagen extractabilities and collagenolytic activities, exceeding ...
Urethral and endocervical swabs and self-collected vaginal swabs (SCVSs) and urine specimens are all used as samples for diagnosis of urogenital infection with Chlamydia trachomatis....Full Text Available
Purpose: To evaluate contrast-enhanced CT scan in the diagnosis of intrahepatic cholangiocarcinoma by correlating the CT appearance with pathologic specimens. Materials and methods: Twenty-eight patients with pathologically proven intrahepatic cholangiocarcinoma were examined. Unenhanced abdominal CT study were performed in 28 patients; conventional contrast-enhanced CT in 27 patients. Enhanced CT scan including fast injection, fast scan and delayed scan at the largest section of the lesion was done in 7 patients. Contiguous 10 mm CT scans of the surgical specimens were also obtained in 8 patients. The preoperative and specimen CT scans in these 8 patients were compared with the corresponding pathological sections. A total of 103 areas of the pathological sections was compared with the CT appearances. Results: All lesions contained areas of delayed contrast enhancement and/or no enhancement on CT examinations. The areas of ...
Experimental data are reported on the micro-irregularities of resistivity in longitudinal and transverse specimens of germanium 0.5 to 0.8 mm in thickness and 25 to 40 mm in width. These data are correlated with the conditions of growth of the crystals. (16 refs).
Over the past few years, tissue microarray (TMA) technology has been established as a standard method for assessing the expression of proteins or genes across large sets of tissue specimens....Full Text Available
Accurate segmentation of tissue microarrays is a challenging topic because of some of the similarities exhibited by normal tissue and tumor regions. Processing speed is another consideration...Full Text Available
The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fuer Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The weld is mechanically loaded during cool-down due to the difference in thermal contractions between the GRP insulation and the aluminium, and during operation by bending moments ...
The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fuer Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The weld is mechanically loaded during cool-down due to the difference in thermal contractions between the GRP insulation and the aluminium, and during operation by bending moments ...
At the importance increase of UT (ultrasonic testing) with the application of rules on fitness-for-service for nuclear power plants, JAPEIC (Japan power engineering and inspection corporation) started education training for defect detection and sizing technique. Weld joints specimen with EDM (Electro-Discharged Machining) notches, fatigue cracks and intergranular stress corrosion cracks were tested and practiced repeatedly based on a modified ultrasonic method and the defect size measuring accuracy of the trainees was surely improved. Results of the blind test confirmed effectiveness of education training. (T. Tanaka)
The low alloy steels were nitrided in the plasma atmosphere generated by using hollow cathode discharge. For comparison, specimens of 40 Cr steel were in two different potential states. One kind is isolated from cathode and anode between them the discharge was created. The other kind is placed on the plate which is connected to the cathode. The nitriding was carried out at different temperatures. The surface morphology, phase of compound layers and microhardness profiles were analyzed. The optical microscopy observation and X-ray diffraction showed that the compound layers were formed in all experiments. The results of the nitriding treatment are weakly dependent on the potentials applied on the specimens.
The microstructure and mechanical properties of a specimen HIPped at 1100 C under 60 ksi were examined. The examinations indicated that the proper HIPping temperature for this material should be higher than 1100 C. New recipe of monolithic material was developed and presented better extrusion homogeneity and less binder removal defects. However, cracking still occurred in specimens although very slow heating rate of 0.25 C/min for binder burnout was used.
High-current implantation of Cu{sup {minus}} ions into silica glasses has been demonstrated using mA-class negative ion beams at 60 keV. Negative ion implantation has an advantage to alleviate specimen charging for insulating substrates and has attained high dose rates, up to 260 {micro}A/cm{sup 2}. Spherical Cu colloids form in the silica glasses without additional thermal annealing. Optical absorption and reflection of the implanted specimens vary with the current density, even at a fixed dose level. A beam-induced surface plasma may affect the high current implantation.
To evaluate the effect of porosity on superplasticity behavior, it is essential to use materials of similar initial grain sizes. This can be achieved by HIPing, which provides an effective way of reducing initial porosity while avoiding appreciable grain growth; various levels of porosity can be achieved for similar grain sizes. This note is concerned with the influence of porosity on superplasticity tensile deformation of a fine grained high-purity alumina doped with copper oxide and containing a grain growth inhibitor. Specimens were prepared by slip casting to net-shape and sintering; some presintered specimens were HIPed to reduce porosity. The subsequent superplasticity behavior is related to porosity in the material.
Recently, a superconducting cryo-electron microscope in which specimens are cooled to the liquid helium temperature (4.2 K) has been developed. The main components and functional features of this new microscope are reported together with application data on polyethylene, poly (4-methyl-1-pentene), valonia cellulose, rock salt, ice crystallites and ceramic superconductor. The resistance to electron radiation damage, of beam-sensitive specimens including polymers has been increased more than ten times. Thus, the microscope has made it possible to take high resolution images and to analyze the crystal-structure of micro-areas. (orig.).
Three bonding agents were evaluated to determine which were most effective in enhancing the bond of resin composite to stainless steel. A light-activated resin composite was bonded to a total of 60 stainless steel specimens using Panavia, Cover-Up, or Silicoating. Tensile bond strength measurements revealed that all three agents provide a satisfactory means of increasing adherence of the esthetic veneer without decreasing bonding through thermocycling of the specimens. Panavia and Cover-Up were significantly more effective than Silicoating and appear to be easier to use. PMID:8297460
Micro-compression specimens, 1O-15{mu}m in diameter by 20-30{mu}m in height, were produced from individual parent grains in a polycrystalline U-13at%Nb shape-memory alloy using the focused ion beam (FIB) technique. The specimens were tested in a nanoindentation instrument with a flat diamond tip to investigate stress-strain behavior as a function of crystallographic orientation. The results are in qualitative agreement with a single-crystal accommodation strain (Bain strain) model of the shape-memory effect for this alloy.
The first part of a systematic investigation is presented of surface treatments affecting the fatigue behavior of smooth and notched quenched and tempered (Q and T) specimens made of a B-Mn SS2131 ({approx}AISI 15B21H) steel. In this part, the effects of plasma nitriding (nitriding temperature=480 C, time=24 h) on the fatigue strength and notch sensitivity were investigated. Constant stress amplitude plane reversed bending fatigue tests (R=-1) at 47 Hz were conducted using cylindrical plasma nitriding (PN) and Q and T steel specimens with K{sub t}=1.05 and 1.7. The compound layer was found to consists of {epsilon}-phase and {gamma}`-phase. S-N curves show that plasma nitriding improves the fatigue limit by 53 and 115% of Q and T smooth and notched specimens, respectively. The fatigue strength of smooth specimens is improved through the whole fatigue life but only for long fatigue lives for notched ...
Uniaxial low-cycle fatigue and creep-fatigue tests have been carried out on hollow alloy 800 specimens that were either filled with air or with a molten mixture of sodium nitrate, potassium nitrate and an oxidizer. Low-cycle fatigue tests were carried out at 1200/sup 0/F and 650/sup 0/F by cycling the strain continuously between equal mangitude of tensile and compressive values at a rate of 4 x 10/sup -3/sec/sup -1/ until failure. The creep-fatigue tests were carried out at 1200/sup 0/F. The loading cycle differed from that of low-cycle fatigue testing only in the imposition of a hold at the peak compressive strain in each cycle. Cracks always initiated on the inner surface of the hollow specimen, and therefore, corrosive effects on crack propagation and initiation were controlled by the environment within the specimen cavity. In common with tests carried out earlier on steam-filled alloy 800 specimens, ...
The objective of this study is to evaluate the lifetime of Zr-2.5Nb pressure tube at Wolsung Unit-1. The testing materials (Effective full power year: 9.3 year, Accumulated nuetron fluence: 7.66{approx}8.91 x 1025 n/m{sup 2}) were sampled from M-11 tube at various position(inlet, middle and outlet). The cutting was carried out at hot cell to fabricate CT(Compact tension) specimen with 48 ppm hydrogen content. In the result of DHC test, irradiation-damaged specimen showed 4{approx}6 times faster DHC velocity(5.298E-0.8{approx}7.039E-8 m/s: 182 .deg. C) than non-irradiated specimen. These DHCV results also show slight faster than one of specimen from Pickering plant (average DHCV: 4.5E-8 m/s: 182 .Deg C). This faster DHCV can be explained with the fact that Wolsung Unit-1 have been operated in a severe conditions(higher cooling water temperature, high power and efficiency) than Pickering one. The ...
The objective of this study is to evaluate the lifetime of Zr-2.5Nb pressure tube at Wolsung Unit-1. The testing materials (Effective full power year: 9.3 year, Accumulated nuetron fluence: 7.66#approx#8.91 x 1025 n/m"2) were sampled from M-11 tube at various position(inlet, middle and outlet). The cutting was carried out at hot cell to fabricate CT(Compact tension) specimen with 48 ppm hydrogen content. In the result of DHC test, irradiation-damaged specimen showed 4#approx#6 times faster DHC velocity(5.298E-0.8#approx#7.039E-8 m/s: 182 .deg. C) than non-irradiated specimen. These DHCV results also show slight faster than one of specimen from Pickering plant (average DHCV: 4.5E-8 m/s: 182 .Deg C). This faster DHCV can be explained with the fact that Wolsung Unit-1 have been operated in a severe conditions(higher cooling water temperature, high power and efficiency) than Pickering one. The striation ...
The influence of substrate temperature on both the implantation and post-annealing characteristics of molecular-ion-implanted 5 x 10{sup 14} cm{sup -2} 77 keV BSi in silicon was investigated in terms of boron depth profiles and damage microstructures. The substrate temperatures under investigation consisted of room temperature (RT) and liquid nitrogen temperature (LT). Post-annealing treatments were performed using rapid thermal annealing (RTA) at 1050 deg, C for 25 s. Boron depth profiles and damage microstructures in both the as-implanted and as-annealed specimens were determined using secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM), respectively. The as-implanted results revealed that, compared to the RT specimen, the LT specimen yields a shallower boron depth profile with a reduced tail into the bulk. An amorphous layer containing a smooth amorphous-to-crystalline (a/c) interface is ...
Limestone slurry needs to move efficiently through a complex process, meaning that selecting the right pumps and valves is critical. The article discusses factors to consider in selecting pumps and values for flue gas desulfurization process in coal-fired power plants. 2 photos.
Economic and performance criteria that should be used in the selection of a scrubber system are presented. Selection should be based on the type of emissions put out by a plant and the removal efficiency required by pollution control standards. Costs and efficiencies for 10 different scrubber systems are reported. (10 diagrams)
BackgroundFeature selection is an important pre-processing task in the analysis of complex data. Selecting an appropriate subset of features can improve classification or clustering...Full Text Available
The development of several DDT-resistant strains of Anopheles atroparvus is described. They were selected by larval treatment only (RL), selection of larval and adult females (RLAF),...Full Text Available
... TITLE (Include Security Classification) Sorption of Selected Volatile Organic Constituents of Jet Fuels and Solvents on Natural Sorbents from Gas ...
Sep 21, 2006 ... NASA has selected Air Products and Chemicals, Inc., Allentown, Pa., to design, furnish and install a plant to produce liquid nitrogen for ...
This document reports the progress and accomplishments of a 16 month program to develop a rechargeable zinc-air battery for electric vehicle propulsion, from October 1988 through January 1990. The program was the first stage in the transition of alkaline zinc electrode technology, invented at Lawrence Berkeley Laboratory, to private industry. The LBL invention teaches the use of a copper metal foam substrate for the zinc electrode, in combination with forced convection of electrolyte through the foam during battery operation. Research at LBL showed promise that this approach would avoid shape change (densification and dendrite growth), the primary failure mode of this electrode. The program comprised five tasks; (1) cell design, (2) capacity maximization, (3) cycle testing, (4) materials qualification, and (5) a cost/design study. The cell design contemplates a plate and frame stack, with alternating zinc and oxygen electrode frame assemblies between rigid end ...
In General Electric's design of the Simplified Boiling Water Reactor (SBWR), The depressurization valves (DPV) are installed in the reactor pressure boundary: four are connected to the reactor vessel by means of nozzles, and two more are located on the main steam pipes (one DPV for each line), which act during particular transients and/or loss of coolant accidents (LOCA), consequently providing the reactor vessel with a safe quick depressurization system. Once the vessel is de pressurised, the passive gravity-driven cooling system (GDCS) starts to operate, permitting the injection of water required for continuous core cooling. DPVs are leak tight, with welded flaps, actuated by a [striker[hammer***] which is activated by an explosive mixture. The dynamic loads that open these valves include, in addition to those produced by steam (typical in any thermodynamic transient with open/close valves), other important loads that are characteristic of this type of explosive valve whose internal ...
Non-destructive testing (NDT) is a dynamic technology and progresses with time. Since the issuance of IAEA-TECDOC-628 in 1991, the technology has experienced numerous changes. Advancements in knowledge about the behaviour of materials have led to changes in the applicable NDT codes, standards and specifications. In addition, over the last ten years, as a result of extensive research and development activities worldwide, new NDT techniques and equipment have been developed which are accepted by engineering community. To accommodate the latest developments, modifications are required to training materials. The present publication is an updated version of IAEA-TECDOC-628. The modifications were made during an Advisory Group Meeting, held in Vienna from 25-29 June 2001. The content of the first edition of IAEA-TECDOC-628 has been revised based on the experience of the experts, as well as comments of the end-user industries. The time allotment for different topics has been changed without ...
It needs accurate estimation of radiation level for verifying machinery and cable in Nuclear Power Plant. Therefore, in this study, we used ESR(Electron Spin Resonance) system for estimate dose of Alanine dosimeter. Alanine/ESR dosimetry, already known as a dosimetric method in medical and industrial field, was applied to estimate dose quantity at cable locations within a nuclear power plant as a part of equipment qualification program. Alanine/ESR dosimetry of absorbed dose range is 1 - 100 KGy. The alanine dosimeter is not significantly affected by temperature and fading is limited to 1% per year. The alanine dosimeters were fixed on the targeted cable or nearest position to measure dose quantity to get accurate value. Alanine dosimeters were scanned by commercially used two different ESR systems, e-scan and EMX series for alanine dosimeters. To estimate more accurate dose, two environmental correction factors, irradiation temperature and dosimeter weight, were ...
The structural acceptance criteria contained herein for the evaluation of existing underground double-shell waste storage tanks located at the Hanford Site is part of the Life Management/Aging Management Program of the Tank Waste Remediation System. The purpose of the overall life management program is to ensure that confinement of the waste is maintained over the required service life of the tanks. Characterization of the present condition of the tanks, understanding and characterization of potential degradation mechanisms, and development of tank structural acceptance criteria based on previous service and projected use are prerequisites to assessing tank integrity, to projecting the length of tank service, and to developing and applying prudent fixes or repairs. The criteria provided herein summarize the requirements for the analysis and structural qualification of the existing double-shell tanks for continued operation. Code reconciliation issues and material ...
The oscillation experiment of free-electron laser (FEL) was carried at the wave length 488 nm. The space and time properties and power of FEL were investigated. The typical macropulse structure indicated the time interval 20 ms and the pulse width 2 to 3 ms. About 1 ns was necessary to build up FEL. The space distribution of FEL showed beautiful TEM_0_0 mode, TEM_0_1 and TEM_0_2 mode. On the basis of data, 39 #mu#W average power was calculated at 2.9 mA accumulated current per bunch by integrating each response of pixel of CCD camera. The peak power was 1.2 W. In the oscillator, FEL power was average 1.2 W, peak 38 kW. On the electron beam, the stability of head tail was controlled by 6-pole-Quadrupole-6-pole (SQS) system made by an experimental basis. We succeeded the single set test, setting up single set in the ring. The characteristic properties of electron beam evaporation mirror of photo oscillator were studied and then new type photo oscillator to obtain large peak power was ...
Shut-off rod drive mechanism forms a safety critical system of a nuclear reactor. It is the space constraints for the given reactor layout, which makes design of shut-off rod drive mechanism (SRDM) a custom built design. Design of SRDM adopts fail-safe, replaceability and the simplicity criterion ensuring very high reliability of its operation. Shut-off rod drive mechanism for TAPP-3 and 4 and 'Critical Facility' have been recently designed and developed at Division of Remote Handling and Robotics (DRHR), BARC. These are designed with a number of advanced features and these are significantly different than those used in Dhruva and 220 MWe PHWRs. Design of SRDM is qualified through proto typing and life cycle testing on a full-scale test set-up. This paper gives details of qualification and life cycle test data for prototype SRDM for TAPP-3 and 4 and 'Critical Facility' and reliability assessment. (author)
Software quality assurance is an area of concern for DOE, EPA, and other agencies due to the poor quality of software and its documentation they have received in the past. This report briefly summarizes the software development concepts and terminology increasingly employed by these agencies and provides a workable approach to scientific programming under the new requirements. Following this is a practical description of how to qualify a simulation code, based on a software QA plan that has been reviewed and officially accepted by DOE/OCRWM. Two codes have recently been baselined and qualified, so that they can be officially used for QA Level 1 work under the DOE/OCRWM QA requirements. One of them was baselined and qualified within one week. The first of the codes was the multi-phase multi-component flow code TOUGH version 1, an already existing code, and the other was a geochemistry transport code STATEQ that was under development The way to accomplish ...
The goal of this project was to demonstrate that a new low-expanding ceramic (Ca{sub 0.6},Mg{sub 0.4})Zr{sub 4}(PO{sub 4}){sub 6}, hereafter referred to as CMZP, could be used as an exhaust manifold liner in off-road diesel engines and provide improved engine efficiency (by permitting higher engine operating temperature). This study has successfully demonstrated this improvement and further engine testing (and possible manufacturing) is presently underway at Caterpillar Inc. Laboratories. Basically this program involved two subcontracts: one to Virginia Tech to develop sintering procedures for CMZP, and one to Caterpillar, Inc. to develop slip casting procedures for CMZP. Nearly 100kg of CMZP were prepared by MATVA, Inc. and Virginia Tech for use by Caterpillar. Virginia Tech developed detailed sintering procedures for CMZP and Caterpillar developed slip casting procedures and manufactured several exhaust manifold elbows. These elbows have been cast into prototype cylinder heads and ...
This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activities to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field ...
PANDA is a large scale facility for investigating the long-term decay heat removal from the containment of a next generation of 'passive' Advanced Light Water Reactors (ALWR). PANDA was used to examine the long-term LOCA response of the Passive Containment Cooling System (PCCS) for the General Electric (GE) Simplified Boiling Water Reactor (SBWR). The first PANDA test series had the dual objectives of demonstrating the performance of the SBWR PCCS and extending the data base available for containment analysis code qualification. The test objectives also include the study of the effects of mixing and stratification of steam and noncondensible gases in the drywell (DW) and in the suppression chamber or wetwell (WW). Ten tests were conducted in the course of the PANDA SBWR Program. The tests demonstrated a favorable and robust overall PCCS performance under different conditions. The present paper focuses on the main phenomena observed during the tests with respect to ...
This technology development plan is designed to provide a clear understanding of the research and development direction necessary for the qualification of nuclear grade graphite for use within the Next Generation Nuclear Plant (NGNP) reactor. The NGNP will be a helium gas cooled Very High Temperature Reactor (VHTR) with a large graphite core. Graphite physically contains the fuel and comprises the majority of the core volume. Considerable effort will be required to ensure that the graphite performance is not compromised during operation. Based upon the perceived requirements the major data needs are outlined and justified from the perspective of reactor design, reatcor performance, or the reactor safety case. The path forward for technology development can then be easily determined for each data need. How the data will be obtained and the inter-relationships between the experimental and modeling activities will define the technology development for graphite ...
The 105-KE and 105-KW Fuel Storage Basins were constructed more than 35 years ago as repositories for irradiated fuel from the K East and K West Reactors. Currently, the basins contain irradiated fuel from the N Reactor. To continue to use the basins as desired, seismic adequacy in accordance with current US Department of Energy facility requirements must be demonstrated. The 105-KE and 105-KW Basins are reinforced concrete, belowground reservoirs with a 16-ft water depth. The entire water retention boundary, which currently includes a portion of the adjacent reactor buildings, must be qualified for the Hanford Site design basis earthquake. The reactor building interface joints are sealed against leakage with rubber water stops. Demonstration of the seismic adequacy of these interface joints was initially identified as a key issue in the seismic qualification effort. The issue of water leakage through seismicly induced cracks was also investigated. This issue, ...
This paper describes the Fast Flux Test Facility (FFTF) Operations initial training program utilizing the Operator Training Simulator (OTS). The OTS is a computer-driven system that provides real time response of essential FFTF plant functions to a control room mockup. The FFTF, a 400 Megawatt, three-loop, sodium-cooled fast test reactor will test fuels, materials and equipment for the U.S. Liquid Metal Fast Breeder Reactor Program. Construction is expected to be completed in August 1978. Initial criticality is expected in early 1979. This schedule will require FFTF control room operators to be fully qualified to operate the facility by late 1979. Because FFTF is like no other U.S. nuclear reactor, existing U.S. utility plants could not be depended on to provide highly experienced people to operate FFTF. Therefore, an Operator Training Simulator has been built. The OTS will play a vital role in the formal operator qualification program.
Alanine/EPR Dosimetry system is classified as a reference-standard dosimeter which used to calibrate radiation environments and to calibrate routine dosimeters in absorbed dose range of 1 to 105 Gy. Characteristics of Alanine/EPR dosimetry system are better suitable than routinely used personnel dosimeters for the long term radiation measurement in harsh condition of Nuclear power plant : This system is not significantly affected by temperature and humidity and also has low fading rate. About 1 year ago, Alanine and Lithium compound dosimeters were installed at Wolsung unit 1 for the environment monitoring as a part of equipment qualification program. 35 positions which are most severe and representative cable positions were chosen for radiation and temperature monitoring. The recovered alanine dosimeter in the period of maintenance was measured by E-scan alanine analyzer system, Meanwhile measurement result shows extremely high radiation level in few points of ...
Alanine/EPR Dosimetry system is classified as a reference-standard dosimeter which used to calibrate radiation environments and to calibrate routine dosimeters in absorbed dose range of 1 to 105 Gy. Characteristics of Alanine/EPR dosimetry system are better suitable than routinely used personnel dosimeters for the long term radiation measurement in harsh condition of Nuclear power plant : This system is not significantly affected by temperature and humidity and also has low fading rate. About 1 year ago, Alanine and Lithium compound dosimeters were installed at Wolsung unit 1 for the environment monitoring as a part of equipment qualification program. 35 positions which are most severe and representative cable positions were chosen for radiation and temperature monitoring. The recovered alanine dosimeter in the period of maintenance was measured by E-scan alanine analyzer system, Meanwhile measurement result shows extremely high radiation level in few points of ...
A detailed outline of the application of the MELCOR and RELAP5/MOD3.1 codes to the analysis of the thermohydraulic response and determination of other parameters of the medium on the floor is given for several classes of secondary coolant circuit accidents along with the description of the related facilities. An overview is presented of the maximum values and time behavior of the thermohydraulic parameters, pressure, temperature, relative humidity, and water level on the floor. Transverse rupture of the steam generator, main steam header, or main feedwater header piping during normal operation is considered as the initiating event. Pressure is only 10% higher than the atmospheric pressure. Air temperature attains a value as high as 100 degC. Relative humidity is 100%, persisting as long as the steam source is available. The water level is typically about 8 cm and never exceeds 15 cm. (M.D.). 16 tabs., 37 figs., 32 refs.
As researchers explore new applications for positron emission tomography radiopharmaceuticals, the demand for effective and readily available radiopharmaceuticals continues to increase. The syntheses of two such radiopharmaceuticals, ["1"1C]acetate and ["1"1C]palmitate, can be automated on the GE Tracerlab FX_C_-_P_r_o by utilizing Grignard reactions. Radiochemical purities of the ["1"1C]acetate and the ["1"1C]palmitate products were high (>98% and >99.9%, respectively) with average non-corrected yields of 18% (n=3) and 10% (n=5), respectively. These data comprise the validation trials for site qualification of clinical production of both radiopharmaceuticals. -- Graphical abstract: Automated syntheses of ["1"1C]acetate and ["1"1C]palmitate using a modified GE Tracerlab FX_C_-_P_r_o are reported. Radiochemical purities of the ["1"1C]acetate and the ["1"1C]palmitate products were high (>98% and >99.9%, respectively) with average non-corrected yields of ...
A new small size gamma irradiator is being set up at Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Brazil, with a revolutionary design. The developed technology for this facility consists of continuous tote box transport system, comprising a single concrete vault, where the automated transport system of products inside and outside of the irradiator utilizes a rotating door, integrated with the shielding, avoiding the traditional maze configuration. Covering 76 m{sup 2} of floor area, the irradiator design is product overlap sources and the maximum capacity of Cobalt-60 wet sources is 37 PBq (1 MCi). The irradiator is being installed in a Governmental Institution and it will be used as a demonstration facility for manufacturers, who need an economic and logistic in-house irradiation system alternative. Also, it will be useful for supporting the local scientific community on development of products and process using gamma radiation, assisting the traditional and ...
Uniaxial low-cycle fatigue and creep-fatigue tests have been carried out on hollow alloy 800 specimens that were filled with steam. Two testing temperatures were employed, each with its own steam condition. These temperatures and steam conditions were 650/sup 0/F with saturated steam (5% liquid, 95% vapor) and 1200/sup 0/F with superheated steam at 2200 psi. The low-cycle fatigue tests were carried out at both 650/sup 0/F and 1200/sup 0/F by cycling the strain between equal tensile and compressive magnitudes until specimen failure or until it was no longer practical to continue the test. The creep-fatigue tests were carried out to failure by cycling the strain in the same fashion as in the low-cycle fatigue tests but with holds imposed at either the peak tensile strain or the peak compressive strain or at both peak tensile and compressive strains in each loading cycle.
Transmission electron microscope (TEM) specimens are today routinely prepared using focussed ion beam (FIB) instruments. Specifically, the lift-out method has become an increasingly popular technique and involves removing thin cross-sections from site-specific locations and transferring them to a TEM grid. This lift-out process can either be performed ex situ or in situ. The latter is mainly carried out on combined dual-beam FIB and scanning electron microscope (SEM) systems whereas conventional single-beam instruments often are limited to the traditional ex situ method. It is nevertheless desirable to enhance the capabilities of existing single-beam instruments to allow for in situ lift-out preparation to be performed since this technique offers a number of advantages over the older ex situ method. A single-beam FIB instrument was therefore modified to incorporate an in situ micromanipulator fitted with a tungsten needle, which can be attached to a cut-out FIB ...
Solubilization of lignite including a large amount of oxygen containing functional groups was attempted using HF/BF3, and the behavior of oxygen containing functional group, one of the important factors for coal liquefaction, was studied. In experiment, the cooled slurry of Yallourn coal specimen and solvent (toluene, isopentane) was filled into a vacuum autoclave together with HF/BF3. Reaction was performed under spontaneous pressure at 50, 100 or 150{degree}C for 3 hours. The distribution of oxygen containing functional groups in each coal specimen was determined by quantification of carboxyl group, hydroxyl group and carbonyl group. As the experimental result, the superacid mixture of HF and BF3 considerably improved the solubility of coal specimens into solvent as compared with individual HF and BF3. The solubility was 68wt% into benzene, 96% into THF and 99% (nearly 100%) into pyridine. It was suggested that production ...
Cyclic voltammograms of SUS 304 stainless steel in various neutral solutions such as Na_2SO_4 at high temperature were measured, as a successive study to previous report in which effects of temperature and pH on polarization behavior of stainless steel were studied. In this measurement Ag/AgCl reference electrode and platinum counter electrode were used in a static autoclave lined with inconel. Passive films formed in various conditions were analysed by electron diffraction and Auger spectroscopy. Results obtained were compared with anodic behavior of iron, chromium and nickel and with thermodynamical stabilities of their compounds. The main results are summarized as follows. (1) Stainless steel shows such electrochemical behavior as active dissolution, passivation and transpassivation in a deaerated neutral solution at 250"0C after fully reductive treatment of the specimen. In air-saturated solution, the peak of active dissolution is not observed. In the passive ...
The low-cycle fatigue properties of the ferritic-martensitic steels MANET I and II and F82H-mod, have been investigated at a temperature of 200 C. The strain-controlled fatigue has been performed with strain ranges between 0,4% and 1,0% and at a strain rate of 8.10{sup -4} s{sup -1}. The steel F82H-mod, is characterised by a higher plastic strain amplitude compared to MANET I and II. Some of the specimens have beenirradiated with a 104 MeV {alpha}-particle beam. The homogeneous implantation of 400 appm He leads to a hardening of the material. At the beginning of the fatigue tests the stress response of the irradiatedspecimens is higher compared to the unirradiated specimens. In general, thematerial shows softening during fatigue. The softening of irradiated material, which is fatigue tested with a high total strain amplitude, is higher than that of the unirradiated material. The lifetime is reduced. For irradiated specimens ...
A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). We investigated mechanical properties, such as the hardness and Young's modulus, of ceramic specimens after superplastic deformation. The tested material was 3Y-TZP (3mol% Yttria stabilized Tetragonal Zirconia Polycrystal) which is one of the representative superplastic ceramics. The properties were measured by a microindentation method. We also studied the relationship between crystal microstructures and the mechanical properties of deformed 3Y-TZP by scanning electron microscope (SEM). The indentation test showed that the mechanical properties of the specimens were reduced to about 1/2 by 30% deformation and to about 1/4 by 150% deformation. The SEM images showed that average grain size and deviation of grain size ...
A duplex surface treatment technique based on calorizing and plasma nitriding was developed to improve the wear and oxidation resistance of H13 steel at high temperatures. The effects of the relative thickness of the calorized layer to the depth of plasma nitriding on the wear and oxidation properties at temperatures up to 900 C were investigated in this work. High-temperature wear tests were performed at 500 C with dry conditions in open air using a ball-on-disk type tribotest machine. Isothermal oxidation tests were performed at 900 C for up to 100 h under controlled atmosphere. The results indicated that the specimens with a calorized layer as an intermediate phase between the surface duplex layer and the base metal showed higher wear and oxidation resistance than the specimens with a nitrided layer alone. During exposure to elevated temperatures, the aluminum in the calorized layer diffused to the surface and formed an aluminum oxide layer. ...
A study has been performed of the initial corrosion of support structure alloys in crevices of various geometries, when galvanically coupled to alloy 600. Corrosion rates were monitored continuously by measuring the galvanic current flowing in each couple, transduced by a zero impedance ammeter. Experiments were performed in a single-pass flowing electrolyte system, with AVT water pumped through alloy 600 tubing past the orifice of each crevice. Fourteen crevices were studied simultaneously in two parallel flow arms containing seven specimens each. The steady state AVT water pH/hydrazine/oxygen concentrations were controlled by microcomputer, allowing the effect of secondary water chemistry on the corrosion rate to be studied easily. Control of the crevice electrolyte composition was achieved by separately pumping electrolyte, at a low rate, directly into the crevices of the seven specimens in the lower flow arm. In addition, a high pressure ...
In support of a project on lifetime calculation experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K{sup Iscc}, and the crack growth rate were made to predict evolution of damage in tube walls. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that the material of SG tubes is sensitive to transgranular environmentally assisted cracking in the three basic concentrated environments used, alkaline, neutral and acid. The most ...
In support of a project on lifetime calculation experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K"I"s"c"c, and the crack growth rate were made to predict evolution of damage in tube walls. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that the material of SG tubes is sensitive to transgranular environmentally assisted cracking in the three basic concentrated environments used, alkaline, neutral and acid. The most corrosive ...
Microwave dielectric properties and far-infrared reflectivity spectra of (Zr{sub 0.8}Sn{sub 0.2})TiO{sub 4} ceramics with 1.0mol.% Sb{sub 2}O{sub 5} or WO{sub 3} were investigated in the various sintering atmospheres. The Q{center_dot}f value of the specimens sintered in oxygen atmosphere was enhanced due to the decrease of lattice anharmonic interaction resulting from the decrease of oxygen vacancies, whereas the dielectric constants remained constant regardless of sintering atmosphere. The effects of the sintering atmosphere on the changes of ionic and electronic polarization and the intrinsic microwave losses of the specimens were investigated by using the infrared reflectivity spectra from 50 to 4000cm{sup -1}, which were evaluated using Kramers-Kronig analysis and classical oscillator model. The relative tendency of microwave dielectric properties of the specimens calculated from the reflectivity data was in good ...
In the corrosion aspect of container for the deep geological disposal of high-level radioactive waste, disposal concepts and the related container materials, which have been developed by advanced countries, have been reviewed. The disposal circumstances could be divided into the saturated and the unsaturated zones. The candidate materials in the countries, which consider the disposal in the unsaturated zone, are the corrosion resistant materials such as supper alloys and stainless steels, but those in the saturated zone is cupper, one of the corrosion allowable materials. By the results of the pitting corrosion test of sensitized stainless steels (such as 304, 304L, 316 and 316L), pitting potential is decreased with the degree of sensitization and the pitting corrosion resistance of 316L is higher than others. And so, the long-term corrosion experiment with 316L stainless steel specimens, sebsitized and non-sensitized, under the compacted bentonite and synthetic ...
The corrosion resistance of steel-reinforced mortar specimens made from alinite cement was investigated using ordinary Portland cement (OPC) specimens as reference. The specimens were prepared and exposed in three different environments: continuous exposure in tap water, interrupted exposure in tap water, and interrupted exposure in 3.5% NaCl solution. The steel weight loss and the half cell potential were measured vs. exposure time, up to the age of 12 months. Pore solution extraction and analysis and porosity determination were also performed. In continuous exposure in tap water, alinite cement provided adequate protection against corrosion. In interrupted exposure in tap water, a higher corrosion was observed for alinite cement compared to OPC. In the case of interrupted exposure in 3.5% NaCl solution, the simultaneous action of free chlorides and oxygen resulted in the depassivation of steel reinforcing bars in alinite ...
Hot-torsion testing was used to establish the cavitation behavior of a typical alpha/beta titanium alloy, Ti-6Al-4V, with a colony microstructure, during simple-shear deformation. For this purpose, sections of deformed specimens were examined by optical metallography, and by scanning and orientation-imaging microscopy (OIM). It was found that cavity nucleation occurred along prior beta boundaries as well as at triple points; in particular, most cavities nucleated along boundaries perpendicular to the axial direction of the specimen. Extensive growth was observed for cavities surrounded by both hard and soft orientations, with the soft colonies accommodating more of the imposed strain. At high degrees of deformation, dynamic globularization of the colony microstructure adjacent to the cavities was also observed. In addition, the metallographic observations revealed that the cavities did not grow in an equiaxed mode, but in an elliptical manner. ...
New and elaborate techniques for alpha-particle autoradiography of thick specimens based on the plastic nuclear track detector CR-39 have been developed. These permit a full analysis of both trace element and microdistribution of alpha-active nuclides present. The important features of the techniques are: 1) reliable low level configuration down to 10/sup -15/ Ci g/sup -1/, 2) high resolution alpha-particle spectroscopy in CR-39, 3) determination of the absolute abundance of alpha active nuclides present in the specimen, 4) determination of the distribution of emission with height up to 30 microns above the surface of the autoradiograph, 5) the local determination of the radon diffusion coefficient in the specimen which is needed to calculate the activity levels of /sup 222/Rn and daughter nuclei, 6) the analysis of small and large clusters of alpha-particle activity recorded on the autoradiograph. These techniques are ...
Full text of publication follows: Radiation hardening and embrittlement due to high-energy neutron radiation around 623 K are the important issues on reduced-activation ferritic/martensitic (RAF/M) steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties of RAF/M after irradiation. It has been reported that the weld joint has less hardening than the base metal from the tensile test results of TIG weldments irradiated in HFIR. This report indicated that radiation hardening can be reduced by the optimization of heat treatment condition for F82H. The purposes of this study are to establish the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. The materials used in this study were F82H IEA heat and F82H heat treatment variants. Neutron irradiation was ...
Background The crucial role of cigarette smoking in the development of pneumothorax is unclear because nonsmokers can also develop primary spontaneous pneumothorax. The purpose of this study was to clarify the pathophysiologic effects of cigarette smoking and its clinical correlations in primary spontaneous pneumothorax. Methods Included were 115 specimens of lung tissue from patients with primary spontaneous pneumothorax who underwent video-assisted thoracoscopic surgery from January 2001 to December 2002. We reviewed the clinical features of 56 smokers and 59 nonsmokers with an average follow-up of 67 months. The pathologic findings of resected lung specimens were analyzed retrospectively. Results There were no statistical differences in sex, age, body height, body weight, body mass inde...
In-situ TEM investigations during thermal treatment of amorphous Pd{sub 81}Si{sub 19} have been performed. It was found that crystalline nuclei are formed near the perforation edge of the hole produced by electrochemical polishing. After impinging with neighboring crystals, a crystallization front formed which was aligned parallel to the perforation edge. The crystallization front moved in the direction perpendicular to the perforation edge. Crystal growth was found to proceed faster in thinner parts of the specimen than in thicker parts. The results are described qualitatively within a thermodynamic model taking into account volume-, surface- and interfacial free energies and an appropriate specimen geometry.
In this study three types of scanning electron microscopes were used for the size determination of spermatozoa of sterlet Acipenser ruthenus - high vacuum scanning electron microscope (SEM, JEOL 6300), environmental scanning electron microscope (ESEM, Quanta 200 FEG), field emission scanning electron microscope (FESEM, JEOL 7401F) with cryoattachment Alto 2500 (Gatan) and transmission electron microscope (TEM, JEOL 1010). The use of particular microscopes was tied with different specimen preparation techniques. The aim of this study was to evaluate to what degree the type of used electron microscope can influence the size of different parts of spermatozoa. For high vacuum SEM the specimen was prepared using two slightly different procedures. After chemical fixation with 2.5% glutaraldehyde...
Appraisals of the isothermal general corrosion of Incoloy 800 in steam at 595 and 650 deg.C indicated good long-term resistance (<7 mg/cm"2 weight gained in 20 years) whether surfaces were ground or electropolished. Electropolished surfaces corroded much faster than ground surfaces in earlier stages, (39 and 15 times as fast in 3000 hr at 595 and 650 deg.C, respectively), but the corrosion rate decreased with time and gave comparable estimates over the long term for both surface preparations. Both nonwelded and welded Incoloy 800 were definately susceptible in chloride stress-corrosion cracking tests of U-bend specimens in a cyclic, wet-dry steam environment. However, C-configuration specimens of Incoloy 800, which were less severly strained, did not crack in this environment. (author).
Eshkaft-e Gavi is a cave located in the southern Zagros Mountains of Iran and is one of the few archaeological sites in the region to preserve both Middle Paleolithic and Upper Paleolithic occupations. Excavation of the site in the 1970s yielded an assemblage of lithic and faunal remains, including ten hominin specimens: a mandibular molar, four cranial fragments, a clavicular diaphysis, the proximal half of a metacarpal, a fragment of os coxa, the proximal diaphysis of a juvenile femur, and a patella. The bones derive from a minimum of four individuals, including two juveniles. Although many of these remains could be Epi-Paleolithic in age, one of the juvenile specimens-the mandibular molar-occurs at the base of the caves Upper Paleolithic sequence. The remains are very fragmentary, but t...
Magnesium alloys are ideal candidates to benefit from equal channel angular extrusion (ECAE) because of their poor forming characteristics due to a hcp structure. In this study, ECAE processing was applied to ZK31 and AZ31 magnesium alloys under various conditions. The grain size of as-ECAE specimens decreases with decreasing the processing temperature, however, the grain size decreases slightly with increasing number of repetitive processing. Both the tensile strength and 0.2% proof stress of as-ECAE specimens are high when processed at low temperature, but the elongation is high when processed at high temperature. Crystal orientation is different in the two alloys and it also varies according to the processing temperature for the two alloys. The difference of the crystal orientation influences the tensile properties, especially 0.2% proof stress. (orig.)
This paper presents a procedure for transferring the CTOD fracture toughness obtained from laboratory specimens to an equivalent CTOD for structural components, taking constraint loss into account. The Weibull stress criterion is applied to correct the CTOD for constraint loss, which leads to an equivalent CTOD ratio, b, defined as b=d/dWP, where d and dWP are CTODs of the standard fracture toughness specimen and the structural component, respectively, at the same level of the Weibull stress. The CTOD ratio b is intended to apply to the fracture assessment of ferritic steel components to stress levels beyond small-scale yielding. Nomographs are given to determine the b-value as a function of the crack type and size in the component, the yield-to-tensile ratio of the material and the Weibul...
The effect of helium on the mechanical properties and fracture behaviors of a type 316 austenitic steel is presented. Helium implantation was performed by 30-MeV #alpha#-particle injection on very small, thin specimens, using a cyclotron accelerator. Average helium content in the He-deposited region was 50 to 2000 appm He. These specimens showed the transition of fracture mode from transgranular to intergranular fracture in elevated temperature tests. The transition temperature decreased with increase in the amount of implanted helium. For example, in the case of 2000 appm and 500 appm He implantation, the transition temperatures were between 773 and 873 K and 873 and 973 K, respectively. (orig.).
Ni-free shape memory alloys are promising functional materials for medical applications. A newly developed Ti-Mo based shape memory alloy shows superelasticity after thermomechanical treatment. However, the microstructure evolution and precipitation during thermomechanical processes are still not well understood. In the present paper, compressive deformation behavior at a series of temperatures of 298K - 973K and tensile deformation behavior of the alloy after aged at 573K - 973K have been investigated systematically. It is found that the compressive yield stress and ultimate compressive strength change with the deformation temperature. The ultimate tensile strength and yield stress of aged specimens also change with the aging temperature following a non-linear relationship. Microstructures of aged specimens as well as effects of lattice softening and aging-induced precipitates on the deformation behavior have been investigated and discussed.
An assessment of the joint shear strength of exterior concrete beam-column joints reinforced internally with Glass Fibre Reinforced Polymer (GFRP) reinforcements under monotonically increasing load on beams keeping constant load on columns is carried out in this study. Totally eighteen numbers of specimens are cast and tested for different parametric conditions like beam longitudinal reinforcement ratio, concrete strength, column reinforcement ratio, joint aspect ratio and influence of the joint stirrups at the joint. Also finite element analysis is performed to simulate the behaviour of the beam-column joints under various parametric conditions. Based on this study, a modified design equation is proposed for assessing the joint shear strength of the GFRP reinforced beam-column specimens b...
This paper describes how hydrogen transport affects the severity of hydrogen embrittlement in 300 M and AerMet100 ultra high strength steels. Slow strain rate tests were carried out on specimens coated with electrodeposited cadmium and aluminium-based SermeTel 1140/962. Hydrogen diffusivities were measured using two-cell permeation and galvanostatic charging methods and values of 8.0 x 10{sup -8} and 1.0 x 10{sup -9} cm{sup 2} s{sup -1} were obtained for 300 M and AerMet100, respectively. A two-dimensional diffusion model was used to predict the hydrogen distributions in the SSR specimens at the time of failure. The superior embrittlement resistance of AerMet100 was attributed to reverted austenite forming around martensite laths during tempering.
The objective of this study was to evaluate the role of collagen membrane and Bio-Oss coverage in healing of an onlay graft to the mandible. Twelve adult sheep each received an onlay bone graft (experiment 1), bone graft+Bio-Gide (experiment 2), and bone graft+Bio-Oss/Bio-Gide (experiment 3) on the lateral surface of the mandible. The animals were euthanized at 4, 8, 12 or 16 weeks after surgery, and findings were analysed by routine microscopy and immunohistochemistry for proliferation (Ki67) and apoptotic (Caspase-3) markers. Grafts were fully incorporated in all specimens. Pronounced resorption was observed in experiment 1. Minimal loss of graft volume was seen in experiment 2 specimens without membrane displacement. A remarkable increase in the augmented region of the mandible was obse...
Grain refinement in AZ31 magnesium alloy has been attempted by hot-rolling and annealing process. Specimens were solution heat treated at 673 K for 36 ks, then hot-rolled at 423-773 K with total reduction of 20-80% by multi pass process. The rolled specimens were annealed at 473-673 K for 3.6 ks. Grain sizes after the solution heat treatment were about 20 to 150 {mu}m. After hot-rolling at 573 K and annealing at 473 K, grain sizes decreased into about 5 to 10 {mu}m. Suppression of grain growth by pinning due to precipitates was observed by transmission electron microscopic observations. (orig.)
Proton induced X-ray emission (PIXE) and proton induced {gamma}-ray emission (PIGE) techniques are employed for the determination of essential and trace elements in some commonly used medicinal plants of north east India. Light elements such as Na, Mg, Al and P are determined by PIGE while medium Z elements such as K, Ca, Mn, Fe, Cu, Zn, Rb and Sr are determined by PIXE. Analysis is performed on pellets (thick targets) prepared using powders of the specimens which, in turn, are obtained following a series of processing steps. Plant based biological certified reference materials (CRMs) served as standards for quantification. These elements are found to be present in varying concentrations in the studied plants, with the contents of Mn and Zn being notably large in certain specimens. Medicinal properties possessed by these plants have been correlated with their elemental distribution.
The nucleation of microdamage under dynamic loading was investigated through planar impact experiments accomplished with a light gas gun. The microscopic observation of recovered and sectioned specimens showed that microcracks were nucleated only by cracking of brittle particles inside material. However, for comparison the in situ static tensile tests on the same material conducted with a scanning electron microscope showed that the microcracks were nucleated by many forms those were fracture of ductile matrix, debonding particles from matrix and cracking of brittle particles. The quantitative metallographic observations of the specimens subjected to impact loading showed that most of the cracked particles were situated on grain boundaries of the aluminum matrix. These facts suggested the concept of critical size and incubation time of submicroscopic cavities in the dynamic case and the mechanism of embryo-damage induced nucleation by fracture ...
Bent specimens of A533B steel (0.16wt% Cu) were irradiated at 290degreeC to 1dpa with 6.4MeV Fe3+ ions. Calculated tensile stresses at the irradiated surface were set to 0, 250, 500 and 750MPa. The specimens were subjected to hardness measurements, transmission electron microscopy (TEM) observations and three-dimensional atom probe (3DAP) analysis. The radiation-induced hardening decreased with increasing stress to 500MPa which was near the yield strength. TEM and 3DAP results showed that well-defined dislocation loops and solute clusters were formed. The diameter of dislocation loops increased and the number density decreased when the stress was applied, whereas the diameter and number density of solute clusters decreased. The hardening was mainly attributed to solute cluster formation. A...
The effect of tsub(A) austenitization temperature in heating for quenching as well as in the cycle of high-temperature thermomechanical treatment (HTMT) on structure, mechanical properties and fracture mode of 40KhN2MA structural steel is investigated. It is shown that heating up to 1200 deg C does not affect essentially sigmasub(b) and sigmasub(0.2) of a quenched material but increases fracture toughness of 200 deg C - tempered precracked specimens and is accompanied by a decrease of impact strength and plasticity of vee-notched specimens. The optimum complex of mechanical properties is attained upon combined treatment comprising heating up to 1200 deg C and HTMT with deformation at 850 deg C.
Stoichiometric MgAl{sub 2}O{sub 4} spinel specimens irradiated in FFTF-MOTA at temperatures between 385 and 750C to fluences ranging from 2.2 to 24.9 {times} 10{sup 22}n cm{sup {minus}2} (E>0.1 MeV) darken significantly, but do not develop any significant loss in weight or change in dimensions. Similar behavior was observed in both single crystal and fully dense polycrystalline specimens. Measurements of elastic constants by an ultrasonic technique show that no measurable changes occur as a result of the irradiation. These and other results confirm the stability of this material for fusion application as an electrical insulator.
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.)
Statement of problem Even though metal ceramic restorations (MCRs) are widely used by clinicians, the influence of the metal on the color of overlaying porcelain is unknown. Purpose The purpose of this study was to analyze the color alterations of different types of metal ceramic alloys during several stages of metal surface preparation and to determine the effect of those changes on the resulting color of opaque porcelain (OP). Material and Methods Seven different types of alloys (3 base metal, 3 noble, and 1 high noble) were used to prepare disk-shaped specimens (1 mm x 10 mm, n=3), followed by OP application (0.1 mm). Lab values of specimens were recorded after different stages of metal surface preparation (ingot, after casting, after oxidation, and after the OP application) in addition...
Bone mineral content as determined by computerized tomography (CT) and mechanical strength on axial loading were compared in 36 cadaveric femur specimens. Based on the CT measurements of density and area, the mass of a transverse slice of the femur was estimated. Highly significant correlations were demonstrated between strength and cancellous bone density. Even higher correlations were revealed when the bone masses of the proximal and distal femoral areas were calculated. Based on these findings, an equal distribution of the effective mass of the femur was postulated. This hypothesis was confirmed in an experimental rotational model. The CT attenuation values were also correlated to direct measurements of bone mineral content, i.e. calcium. Moreover, the strength of different metal implants, commonly used in femoral neck fractures, were assessed in cadaver specimens. 134 refs., 13 figs., 12 tabs.
? Introduction For large trees without a continuous sequence of growth rings in their trunk, such as the African baobab (Adansonia digitata L.), the only accurate method for age determination is radiocarbon dating. As of today, this method was limited to dating samples collected from the remains of dead specimens. ? Methods Our research extends significantly the dating of such trees to large live specimens with inner cavities. The new approach is based on collecting samples from the cavities and their subsequent radiocarbon dating. ? Results The giant two-stemmed Platland tree, also known as Sunland baobab, was investigated by using this new approach. AMS radiocarbon dates of the oldest sample segments originating from the two inner cavities indicate that the large stem I (364.5?m3) is 750...
Having know of four more natural hot spring located in Amphur Phipun, Nakorn Si Thammarat Province, the present investigators went on July 27, 2005 to collect water samples from the four new hot springs in Ampur Phipun, Nakorn Si Thammarat Province. The methods of collection and the determination of radon gas and free-living amoeba were the same as those employed in previous studies. The results revealed radon concentrations higher than the drinking safety limits of 11 Bq/L in specimens from Baan Huaysai Kow (32.30 Bq/L) and Baan Hunob (31.18 Bq/L; both naegleria and acanthamoeba were present in the specimens of the above two sites, whereas only naegleria recovered from Baan Huaysai Kow (Nai Nukul place) and none from Baan Nong Bua.
A new technique was proposed in order to improve poor corrosion resistance in magnesium. That is, magnesium hydroxide film was formed on the surface of 3 N-Mg by artificial corrosion in 1% MgCl{sub 2} solution for 3.6 ks, which followed by oxidation at 673 K for 3.6 ks in air. Corrosion resistance was evaluated by salt immersion tests in 1% NaCl solution under in situ laser microscopic observations. Bubble evolution, which occurred immediately at the beginning of the immersion test in the case of non-treated specimen, was suppressed by the process. And also, formation of filiform corrosion was suppressed for about 3.6 ks, which occurred at 180 s in the non-treated specimen. (orig.)
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.
Despite the rapid development of literature pertaining to fundamental (1-4) studies of oxidation catalysis, a general theory of heterogeneous selective oxidation catalysis explaining the selectivity behavior of different metal oxide systems has not yet been developed. Redox mechanisms have been widely invoked in the kinetic and mechanistic descriptions of selective oxidation reactions, suggesting a dynamic behavior of hydrocarbon and oxygen interactions with the catalyst surface. Nevertheless, most of the recent theoretical approaches of this subject matter (5-7) are essentially static in nature. Correlations are made with surface structure on the basis of crystallographic considerations with selectivity being related to the nature, number, bond-strength and nearness of oxygen atoms in the neighborhood of adsorption centers. The effect of the reaction medium on the configuration of the catalyst surface, ...
Craters were produced in the surface of a Pt-specimen by plasma discharge. Using a Focussed Ion Beam (FIB), TEM-foils of the cross section of the craters were prepared in order to examine the microstructural changes occurring as a result of the discharge impact. The molten material pushed to the edge of the craters was able to be identified. The grains beneath the craters reached the surface of the crater by a mechanism of epitaxial growth. (orig.)
The swelling behavior which results from simulated fusion environment irradiation of Fe-10% Cr has been characterized with transmission electron microscopy. Specimens were bombarded at 850 K with: a ''triple-beam'' of He"+, D_2"+, and 4 MeV Fe"+"+ ions to 0.3, 1, 3, 10, 30, and 100 dpa (displacement per atom); a ''dual-beam'' of He"+ and 4 MeV Fe"+"+ ions to 30 and 100 dpa; and a ''single-beam'' of 4 MeV Fe"+"+ ions to 30 dpa. The helium and hydrogen injection rates were approx. =10 appm He/dpa and approx. =40 appm D/dpa. Cavities were observed for damage levels of 3 dpa and greater. The swelling was <0.1% for damage levels <30 dpa, but at 100 dpa, there was an increase in the swelling to 2.5% for the ''triple-beam'' irradiation and 1.2% for the ''dual-beam'' irradiation. The swelling rates between 30 and 100 dpa correlate well with calculated values assuming a steady-state swelling-rate regime has been reached. Calculations show the rapid cavity growth ...
A focused ion beam (FIB) system has been applied to prepare a thin foil specimen of Si, MgO and alumina which contained cracks in the plan of foil. It was possible to observe a much larger area at and near a crack tip than has been hitherto possible. FIB was also applied to observation of microstructure near a crack tip evolved during severe rolling contact fatigue in a steel.
The pitting corrosion resistance of three different types of stainless steel implanted with silicon is investigated using the potentiokinetic polarization technique. The specimens are tested in 3% NaCl and 0.1 N HCl solutions. Silicon ion implantation inhibits pitting corrosion of the steels in both aqueous media. The corrosion resistance depends on the silicon dose. Post implantation annealing only slightly alters the localized corrosion. (author).
New standardization techniques of samples in multielement instrumental neutron-activation analysis (INAA) of biological materials (BM) are considered. New methodical developments of sample preparation techniques, BM tableting, creation of comparison standards and standardization of packing material are suggested. Correlated data on concentration of different elements in standard specimens-comparison standards are presented for mass INAA, that is: for phenol-formaldehyde resin-base and human blood-base synthetic standards. 7 refs.; 3 tabs.
Over the past several years, the Livermore Forensic Science Center has conducted analyses of nuclear-related samples in conjunction with domestic and international criminal investigations. Law enforcement officials have sought conventional and nuclear-forensic analyses of questioned specimens that have typically consisted of miscellaneous metal species or actinide salts. The investigated activities have included nuclear smuggling and the proliferation of alleged fissionable materials, nonradioactive hoaxes such as 'Red Mercury', and the interdiction of illegal laboratories engaged in methamphetamine synthesis. (author)
High purity MgAl{sub 2}O{sub 4} spinel specimens irradiated in FFTF-MOTA to very high exposure have been examined by three techniques to determine changes in their optical properties. Significant changes were observed in optical absorption, photoluminescence and radioluminescence.
Hydrothermal method for preparing crystal borophosphate with zeolite structure is suggested. To increase absorption capacity and thermal stability of final product, aluminium hydroxide sol, ethylenediamine and ethyl acetate are added to the mixture of crystal boric and concentrated phosphoric acids. Thermal stability of the specimens prepared constitutes 880-950 deg, water absorption capacity is within the limits of 0.30-0.32 cmT/g. 1 table.
In this work a Ni-based superalloy GMR 235 was investigated. We determined convenient metallographic methods for preparation of bulk metallographic specimens, extraction carbon replicas, transparent metallic foils and minor phase extraction. In addition, the alloy microstructure was characterised using different metallographic techniques. (orig.)
The electrical resistivity at low temperatures (T = 10 to 90 K) of the lithium isotopes /sup 6/Li and /sup 7/Li and of an isotopic mixture /sup 7 +6/Li has been studied. The specimens contained a small amount of chemical impurities. An appreciable difference was observed in the temperature dependence of the resistivity produced both by deformation of the phonon spectrum, related to the change in isotopic composition, and by the presence of chemical impurities making the nonequilibrium part of the electron distribution function more isotropic.
Using commercial AZ31 magnesium alloy sheets, we produced a foamable preform sheet containing titanium hydride (TiH{sub 2}) powder through diffusion-bonding and hot-rolling of four cycles. Heating the preform sheets in Ar atmosphere, we obtained closed-cell magnesium alloy foams with various porosities. The foamed specimen at 883 K showed the maximum porosities of 77%. (orig.)
We have examined spontaneous secretion of IgE by human rib bone marrow mononuclear cells (MNC). Bone marrow MNC from nine out of 12 rib specimens synthesized and secreted substantial amounts of IgE...Full Text Available
Large (about 200 grams dry weight) and small (about 5 grams dry weight) specimens of the leaf succulent Agave vilmoriniana Berger were grown outdoors at Phoenix, Arizona. Potted plants...Full Text Available
Under the current design philosophy, reactor structures are to be designed to withstand large inelastic deformation caused by strong and severe ground motion. The design of the main structural elements and their connections are to be such that they always fail in ductile mode. This will ensure large energy absorption capacity of the structures under seismic excitation and avoid sudden and brittle failure of the structure. Over the years, a number of experimental investigations have been carried out on RC beam- column joints to study their behaviour and strength. However, these studies mostly pertain to small scale joints of moment resisting frame of residential buildings and commercial complexes. Information on full scale joints existing in NPP structures are scanty. Therefore, experimental programme was planned in the laboratory to construct identical large sized joints with the same reinforcement percentage and detail as that of the existing joints in NPP structures built in 1960's. ...
Threshold pump intensity values leading to irreversible damage to colored laser elements based on elastic polymers were measured. The damage to colored elastomers is connected with absorbing microinclusions but is independent of molecular absorption. It is shown that damage to the elastomers has a pronounced threshold character in contrast to the microdamage accumulation effect in glassy polymers. The damage threshold for elastomers is 1.5 times higher, which is connected with the absence of microstresses (characteristics for organic glasses) in the specimens. 13 references.
The ductility of extruded heavy-section Ti-base--Mo--V--Fe--Al alloy was studied. Metallographic evidence for the large effect of grain size on ductility is presented. Fracture was found to occur in large-grain material after less deformation than in smaller grain size specimens.
The sensitivity and specificity of the MGIT TBc identification (TBc ID) test for Mycobacterium tuberculosis complex (MTC) detection in positive Bactec MGIT cultures were 95.2% and 99.2%, respectively. When MTC-positive results obtained from two additional molecular methods were included, the sensitivity of the MGIT TBc ID test was 85.4%, while that of culture was 95.7%. PMID:21450949
Density changes in amorphous Pd{sub 80}Si{sub 20} during ion irradiation below 100K were detected by in situ HVEM measurements of the changes in specimen length as a function of ion fluence. A decrease in mass density as a function of the ion fluence was observed. The saturation value of the change in mass density was determined to be approximately -1.2%.
Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a psoitive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys. (orig.).
Intrahepatic cholangiocarcinoma is an uncommon tumor as primary hepatic neoplasm. Five cases of cholangiocarcinoma, mass forming peripheral type, are reported about its CT findings. They were manifested as a poorly marginated low density mass with a irregular stellate area. In one case, a cut section of the gross specimen following surgery showed a central callagenous scar and vessels within the necrotic tumor. (author).
The Fast Flux Test Facility (FFTF) reactor characterization by the Hanford Engineering Development Laboratory (HEDL) includes extensive neutronic measurements during startup and initial operation. To aid in the handling and counting of the thousands of passive dosimeters used as part of this effort, an automated dosimetry specimen handling, positioning, and counting system was designed and developed by Westinghouse Hanford for the Department of Energy.
The applicability of conventional strength hypotheses in the long-term creep range was examined by means of multiaxial loaded small and large-scale specimens of 1% CrMoNiV-steel at 550deg C. The experimentally determined deformation behaviour in the primary and secondary creep range was simulated by means of a finite element analysis. The creep deformation capacity is influenced by the degree of multiaxiality. The validity of a strength hypothesis depends on the type of load and on deformation resp. failure criteria. (orig.).
Recent development in application of a focused ion beam (FIB) technique to preparation of thin foil specimens for transmission electron microscopy (TEM) observation has been reviewed. Combined technique of FIB/TEM enables one to analyze those microstructures which have been almost impossible or very difficult to analyze so far. (author)
In a suicide committed using aluminium phosphide (AlP) the liberated toxic phosphine gas was detected in post-mortem specimens using a headspace gas chromatographic procedure with a nitrogen-phosphorous detector (HS-GC/NPD). At autopsy a direct sampling into airtight headspace vials for a later analysis is recommended. AlP has to be considered a potent pesticide and its use and availability should be restricted as much as possible.
The purpose of this study was to use high-resolution magnetic resonance (MR) imaging combined with image analysis to investigate the three-dimensional (3D) trabecular structure, anisotropy, and connectivity of human vertebral, femoral, and calcaneal specimens. The goal was to determine whether: (a) MR-derived measures depict known skeletal-site-specific differences in architecture and orientation of trabeculae; (b) 3D architectural parameters combined with bone mineral density (BMD) improve the prediction of the elastic modulus using a fabric tensor formulation; (c) MR-derived 3D architectural parameters combined with BMD improve the prediction of strength using a multiple regression model, and whether these results corresponded to the results obtained using higher resolution depictions of trabecular architecture. A total of 94 specimens (12 x 12 x 12 mm cubes) consisting of trabecular bone only were obtained, of which there were 7 from the ...
Educational data mining (EDM) is a new growing research area and the essence of data mining concepts are used in the educational field for the purpose of extracting useful information on the behaviors of students in the learning process. In this EDM, feature selection is to be made for the generation of subset of candidate variables. As the feature selection influences the predictive accuracy of any performance model, it is essential to study elaborately the effectiveness of student performance model in connection with feature selection techniques. In this connection, the present study is devoted not only to investigate the most relevant subset features with minimum cardinality for achieving high predictive performance by adopting various filtered feature selection techniques in data mining but also to evaluate the goodness of subsets with different cardinalities and the quality of six filtered feature ...
ObjectiveThe objective of this study was to identify patterns of brain activation elicited by erotic visual stimuli in patients treated with either Selective Serotonin Reuptake Inhibitors...Full Text Available
The objectives of this study were to select and initially characterize mutants of soybean (Glycine max L. Merr. cv Williams) with decreased ability to reduce nitrate. Selection involved...Full Text Available
Selective estrogen receptor modulators (SERMs) represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This article...Full Text Available
Types of disorders in the earth's surface as a result of open pit mining operations are analyzed. Trends for recultivation of lands are defined. Formulas are presented for calculating the economic expediency of the selected direction of recultivation.
BackgroundUnderstanding the interactions between ion channels and blockers remains an important goal that has implications for delineating the basic mechanisms of ion channel function...Full Text Available
The objectives of this research are: (1) to assess selected formulation-relevant physical properties of several commercial Feverfew extracts, including flowability, hygroscopicity, compressibility and...Full Text Available
Direct identification of group B streptococci from a selective broth medium was performed with the Phadebact streptococcus test to determine the feasibility of this technique for early detection of...Full Text Available
We evaluated whether ejaculatory dysfunction induced with a selective α1A-blocker influenced orgasm. Fifteen healthy male volunteers took silodosin or a placebo in a randomized, double-blind...Full Text Available
Importance of the fieldThe cytochrome P450 (CYP) isoforms that are selectively induced following exposure to structurally-diverse chemicals often are the ones capable...Full Text Available
BackgroundScorpion venom contains insect and mammal selective toxins. We investigated the venom of the South Indian red scorpion, Mesobuthus tamulus for the purpose...Full Text Available
With the advent of dense maps of human genetic variation, it is now possible to detect positive natural selection across the human genome. Here we report an analysis of over 3 million polymorphisms...Full Text Available
BackgroundMicroarray data are often used for patient classification and gene selection. An appropriate tool for end users and biomedical researchers should combine user friendliness...Full Text Available
OBJECTIVE: To evaluate the commercial microparticle enzyme immunoassay (MEIA), Abbott IMx Select Chlamydia, for the detection of Chlamydia trachomatis in women and to compare its performance with endocervical...Full Text Available
We compared MRSA Select to mannitol-salt agar with 8 μg/ml cefoxitin for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from 6,199 clinical...Full Text Available
Many pathogens colonize different anatomical sites, but the selective pressures contributing to survival in the diverse niches are poorly understood. Group A Streptococcus (GAS) is...Full Text Available
In this paper, we propose an antenna selection method in a wireless cognitive radio (CR) system, namely difference selection, whereby a single transmit antenna is selected at the secondary transmitter out of $M$ possible antennas such that the weighted difference between the channel gains of the data link and the interference link is maximized. We analyze mutual information and outage probability of the secondary transmission in a CR system with difference antenna selection, and propose a method of optimizing these performance metrics of the secondary data link subject to practical constraints on the peak secondary transmit power and the average interference power as seen by the primary receiver. The optimization is performed over two parameters: the peak secondary transmit power and the difference selection weight $\\delta\\in [0, 1]$. We show that, difference ...
Recombinant biotin-binding phages were affinity-selected from a random peptide library expressed on the surface of filamentous phage. Phage binding to biotinylated proteins was half-maximally inhibited...Full Text Available
OBJECTIVES: Although the tricyclic antidepressant amitriptyline is extensively used in the prophylactic treatment of chronic tension-type headache, only few studies have investigated the efficacy of...Full Text Available
Six patient assessment systems that have explicit decision rules for replicating team judgments on level of care patient placement were selected for analysis. The six were selected because of their...Full Text Available
Surface temperature is measured with an infrared thermometer. Measuring Surface Temperature. Nine sample points are selected with a site of uniform land ...
Selection of detailed-items for Periodic Safety Review on PWR radwaste management system, the main component could be faithfully clarified according to the purpose of establishment on each system and basic purpose. It is proper to select detailed-items those of radioactivities in the reactor coolant activity levels and the released volume of liquid and gaseous radioactive material on safety performance. It's also proper to select solid radwaste production quantities as detailed-item that it would be predict the next ten years trends after PSR.
2.1.1 Levels of preservation and packaging and the levels of packing to be applied selectively are defined in MIL-STD-2073-1 and are mandatory for use or ...
Current technical specifications of Wolsong Unit 2,3,4 was analyzed and improvement methods was suggested to develop Improved Standard Technical Specifications(ISTS) of PHWR. The selection criteria of PHWR limiting condition for operation(LCO) was established, then limiting conditions for operationl were selected. The number of current LCOs for Wolsong Units 2,3,4 is 109, and 46 LCOs(42%) were relocated by the selection criteria of PHWR LCO. 63 LCOs which met the selection criteria of PHWR LCO were recomposed to 59 LCOs.
The article explains the method of selecting the optimum energy for correcting the energy selectivity of tomographic projection and the optimum length of the crystals corresponding to it when the dual energy method in computerized tomography is used. Results of numerical calculations for actual materials and count results are presented.
In this paper, a new design methodology for determining the size, location, type and number of capacitors to be placed on a radial distribution system is presented. The objective is to minimize the peak power losses and the energy losses in the distribution system considering the capacitor cost. A sensitivity analysis based method is used to select the candidate locations for the capacitors. A new optimization method using a Genetic Algorithm is proposed to determine the optimal selection of capacitors. Test results have been presented along with the discussion of the algorithm.
Investigation of selective emitter solar cells has been undertaken using both device fabrication and accurate two-dimensional simulation program. Our results show that selective emitter solar cells exhibit a relatively low fill factor because of minority carriers crowding at the lateral junction. It is also found that carrier recombination in the space-charge region of the lateral junction limits open-circuit voltage improvements
Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)
Supplement B to the Terra Nova Development Application provides a description of the floating production storage and offloading (FPSO) vessel system selected for the development, a summary of the reasons for selecting the system, and the impact of this selection on the Development Plan, the Benefits Plan, the Environmental Impact Statement and the Socio-Economic Impact Statement. There is also a description of the contractor alliance approach to be used in the Terra Nova Development. Refs., tabs., figs.
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.
We report the influence of a small quantity of Cl[sub 2], which enhanced the selectivity of silicon-selective epitaxial growth (Si-SEG) in UHV-CVD using Si[sub 2]H[sub 6], on both the epitaxial growth rate and the B-doping properties for each Si and Si[sub 1-x]Ge[sub x] film. The small quantity of Cl[sub 2] inhibited the Si, Ge and B incorporation, while the selectivity was enhanced. However, it was found, in the case of Si[sub 1-x]Ge[sub x]-SEG using Cl[sub 2], that the reduction ratio of both the growth rate and the B incorporation were smaller than those of Si-SEG with the selectivity still more enhanced. (orig.)
Selective formation of ZnO nanodots was accomplished by metalorganic chemical vapor deposition on nanopatterned SiO_2/Si substrates. Self-organized ZnO nanodots were selectively formed in nanopatterned lines of Si created by etching of SiO_2 with focused ion beam (FIB), whereas any nanodots were hardly observed on the SiO_2 surface in the vicinity of the FIB-sputtered Si areas. The mechanism of the selective formation of ZnO nanodots on FIB-nanopatterned lines is mainly attributed to the effective migration of Zn adatoms diffusing on the SiO_2 surface into the Si lines followed by the nucleation at surface atomic steps and kinks created by Ga"+ ion sputtering. Cathodoluminescence measurements confirmed that the emission originated from the selectively grown ZnO nanodots.
Model selection aims to determine which theoretical models are most plausible given some data, without necessarily asking about the preferred values of the model parameters. A common model selection question is to ask when new data require introduction of an additional parameter, describing a newly-discovered physical effect. We review several model selection statistics, and then focus on use of the Bayesian evidence, which implements the usual Bayesian analysis framework at the level of models rather than parameters. We describe our CosmoNest code, which is the first computationally-efficient implementation of Bayesian model selection in a cosmological context. We apply it to recent WMAP satellite data, examining the need for a perturbation spectral index differing from the scale-invariant (Harrison-Zel'dovich) case.
Feature selection refers to the problem of selecting relevant features which produce the most predictive outcome. In particular, feature selection task is involved in datasets containing huge number of features. Rough set theory has been one of the most successful methods used for feature selection. However, this method is still not able to find optimal subsets. This paper proposes a new feature selection method based on Rough set theory hybrid with Bee Colony Optimization (BCO) in an attempt to combat this. This proposed work is applied in the medical domain to find the minimal reducts and experimentally compared with the Quick Reduct, Entropy Based Reduct, and other hybrid Rough Set methods such as Genetic Algorithm (GA), Ant Colony Optimization (ACO) and Particle Swarm Optimization (PSO).
We consider relay selection technique in a cooperative cellular network where user terminals act as mobile relays to help the communications between base station (BS) and mobile station (MS). A novel relay selection scheme, called Joint Uplink and Downlink Relay Selection (JUDRS), is proposed in this paper. Specifically, we generalize JUDRS in two key aspects: (i) relay is selected jointly for uplink and downlink, so that the relay selection overhead can be reduced, and (ii) we consider to minimize the weighted total energy consumption of MS, relay and BS by taking into account channel quality and traffic load condition of uplink and downlink. Information theoretic analysis of the diversity-multiplexing tradeoff demonstrates that the proposed scheme achieves full spatial diversity in the quantity of cooperating terminals in this network. And numerical results are provided to further ...
Effect of low-frequency pulsating magnetic field on the microstructure and magnetic properties of amorphous alloy Fe_7_8Si_9B_1_3 were investigated. The temperature rise induced by the treatment was measured by a non-contact infrared thermometer. The crystallization behavior and microstructure of specimens were studied by Moessbauer spectroscopy and transmission electron microscope (TEM). Magnetic properties of the specimens were investigated by alternating gradient magnetometer (AGM). The results show that the low-frequency pulsating magnetic field can promote the single-phase crystallization of amorphous alloy Fe_7_8Si_9B_1_3. The frequency, f of applied field is from 10 to 40 Hz, magnetic field, H is from 0.02 to 0.04 T and treatment duration, t is from 180-300 s. The volume fraction of crystallization phase (#alpha#-Fe(Si), the grain size, 2-10 nm) is 3-7%. The temperature rise less than 7 deg. C. Magnetic properties of samples are improved ...
The swelling and in-reactor creep behaviors of the PCA alloy have been determined from the irradiation of pressurized tube specimens in the FFTF reactor. These data have been obtained to a peak neutron fluence corresponding to approximately 80 dpa in the FFTF reactor for irradiation temperatures between 400 and 750/sup 0/C. Diametral measurements performed on the unstressed specimens indicate the possible onset of swelling in the PCA alloy for irradiation temperatures between 400 and 550/sup 0/C and at a neutron fluence corresponding to approx.50 dpa. The creep data suggest a non-linear fluence dependence and linear stress dependence (for hoop stresses less than 100 MPa) which is consistent with the in-reactor creep behavior of many cold worked austenitic stainless steels. These PCA creep data are compared to available 316 SS in-reactor creep data. The in-reactor creep strains for PCA are significantly less than observed in 20% cold worked 316 ...
The swelling and in-reactor creep behaviors of the PCA alloy have been determined from the irradiation of pressurized tube specimens in the FFTF reactor. These data have been obtained to a peak neutron fluence corresponding to approximately 80 dpa in the FFTF reactor for irradiation temperatures between 400 and 750"0C. Diametral measurements performed on the unstressed specimens indicate the possible onset of swelling in the PCA alloy for irradiation temperatures between 400 and 550"0C and at a neutron fluence corresponding to #approx#50 dpa. The creep data suggest a non-linear fluence dependence and linear stress dependence (for hoop stresses less than 100 MPa) which is consistent with the in-reactor creep behavior of many cold worked austenitic stainless steels. These PCA creep data are compared to available 316 SS in-reactor creep data. The in-reactor creep strains for PCA are significantly less than observed in 20% cold worked 316 SS over ...
The behavior of MEMS devices is limited by the strength of critical features such as thin ligaments, oxide cuts joining layers, pin joints and hinges. Devices fabricated at Sandia's Microelectronic Development Laboratory have been successfully tested to investigate these features. A series of measurements were performed on samples with gage lengths of 15 to 1000 microns, using conventional and tungsten coated samples as well as samples that include the critical features of standard components in the test section. Specimens have a freely moving pin joint on one end that anchors the sample to the silicon die to allow rotation to reduce effects of bending. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. Load is calculated by resolving the measured lateral and normal forces into the applied tensile force and frictional losses. The specimen cross section and ...
Connective tissue in biopsy specimens taken from the lower part of the uterine cervix in 40 pregnant women at various gestational ages was compared to that in similar biopsy specimens from 15 nonpregnant women. The concentrations of collagen, sulfated glycosaminoglycans, and hyaluronic acid decreased during pregnancy. At the gestational age of 10 weeks, the collagen concentration was 70%, and at term 30%, of that in the nonpregnant cervix. After delivery, no further decrease was observed. The extractability of collagen increased during pregnancy, as well as during labor. Also, the water concentration increased. An increase in the collagenolytic activity was observed with advancing gestational age. The 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gin-D-Arg hydrolytic activity (collagenase) and the concentration of leukocyte elastase increased gradually by a factor of 10. The physiologic importance of the collagen was also demonstrated, since the ...
Type 304 stainless steels (solution annealed material, cold worked material and fine grain material) were neutron irradiated to 3 x 10"2"5n/m"2 at 290degC and at 50degC. Each specimen was examined by SSRT test in high temperature water with 8 ppm dissolved oxygen and Ar gas environments. Results were as follows: (1) IASCC susceptibility of each material can be classified by 0.2% proof stress (PS) obtained from SSRT test in Ar gas: No IASCC susceptibility was observed in the PS range 850 MPa. (2) The uniform elongation (UE) in Ar gas environment decreased with increasing PS up to 800 MPa, and became about 0% in the PS range >800 MPa. (3) It was suggested that IASCC did not occur even if material had IASCC susceptibility, when under a condition that brittle fracture mechanism controls a specimen failure. (author)
The bullet evidence in the JFK assassination investigation was reexamined from metallurgical and statistical standpoints. The questioned specimens are comprised of soft lead, possibly from full-metal-jacketed Mannlicher-Carcano, 6.5-mm ammunition. During lead refining, contaminant elements are removed to specified levels for a desired alloy or composition. Microsegregation of trace and minor elements during lead casting and processing can account for the experimental variabilities measured in various evidentiary and comparison samples by laboratory analysts. Thus, elevated concentrations of antimony and copper at crystallographic grain boundaries, the widely varying sizes of grains in Mannlicher-Carcano bullet lead, and the 5-60 mg bullet samples analyzed for assassination intelligence effectively resulted in operational sampling error for the analyses. This deficiency was not considered in the original data interpretation and resulted in an invalid conclusion in ...
A model has been developed in the recent past to predict fatigue crack growth (FCG) behaviour in the Paris-regime of various steels by employing low cycle fatigue (LCF) properties. The model forms its basis on the assumption that the cyclic damage process immediately ahead of a crack-tip, restricted in a small zone termed as process zone, is identical to those experienced in the LCF loading of a smooth specimen. Within the process zone, fatigue damage has been assumed in terms of product of stress and plastic strain which is analogous to the plastic strain energy density of the smooth specimen under fatigue loading. In this paper the model developed by Kujawski and Ellyin has been used to predict the FCG behaviour of an #alpha#-#beta# titanium alloy in the Paris-regime by employing the experimentally obtained LCF properties. The FCG behaviour thus theoretically predicted was compared with the experimentally determined FCG behaviour.
As for surface treatment of steel, the ion nitriding method has a lot of advantages and is practically used, while the plasma nitriding is known as a method which is faster in nitriding than the ion nitriding method. However, there are few reports and many unclear points on the plasma nitriding method. In this study, the plasma nitriding of pure iron and SUS304 is conducted using r.f. nitrogen plasma glow discharge to examine composition of the nitrided layers, microstructures, nitriding rate, etc. Moreover, by exposing the specimen once nitrided to H2 plasma, a phenomenon that nitrogen comes out of the specimen surface is examined. It is found from the result that the nitrided layer is divided into a compound layer and a diffusion layer in order from the surface, that in case of pure iron, the compound layer grows predominantly at a low temperature, and the diffusion layer grows predominantly at a high temperature, that in case of SUS304, both ...
Continuous metallic glass ribbons were produced by mejans of liquid-quenching at rates >10/sup 50/C/s. The ribbons, typically 30 ..mu..m thick and 1 to 2 mm wide, were determined to be glassy by X-ray diffraction (XRD) employing CuK..cap alpha.. and MoK..cap alpha.. radiation. Mechanical properties of the as-quenched product were determined by measurements of hardness, tensile strength and Young's modulus. The Vicker's diamond pyramid microhardness (H/sub V/) was measured on epoxy mounted samples using a Lietz Miniload instrument with a 100 g load. Tensile tests were conducted in an Instron machine using specimens which were hand-polished to produce smooth, parallel sides. Young's modulus (E) is given by the relationship rho V/sub E/sup 2//. V/sub E/, the velocity of extensional mode waves, was measured by the pulse-echo technique using a Panametrics Intervalometer and glass density, rho, was obtained by the liquid immersion method. ...
The microstructure of the secondary deformation zone (SDZ) near the cutting surface in metal chips of Ti-6Al-4V formed during machining was investigated using focused ion beam (FIB) specimen preparation and transmission electron microscopy (TEM) imaging. Use of the FIB allowed precise extraction of the specimen across this region to reveal its inhomogeneous microstructure resulting from the non-uniform distribution of strain, strain rate, and temperature generated during the cutting process. Initial imaging from conventional TEM foil preparation revealed microstructures ranging from heavily textured to regions of fine grains. Using FIB preparation, the transverse microstructure could be interpreted as fine grains near the cutting surface which transitioned to coarse grains toward the free surface. At the cutting surface a 10 nm thick recrystallized layer was observed capping a 20 nm thick amorphous layer.
Alumina (94 and 99.8% grade compositions) was brazed directly to itself with gold-based active brazing alloys (ABA's) containing vanadium additions of 1,2 and 3 weight percent. The effects of brazing conditions on the joint properties were investigated. Wetting behavior, interfacial reactions, microstructure, hermeticity and tensile strength were determined. Wetting was fair to good for the ABA and base material combinations. Microanalysis identified a discontinuous Al-V-O spinel reaction product at the alumina-braze interface. Tensile strength results for 94% alumina were uniformly good and generally not sensitive to the vanadium concentration, with tensile values of 85-105 MPa. There was more variability in the 99.8% alumina strength results, with values ranging from 25-95 MPa. The highest vanadium concentration (3 wt. %) yielded the highest joint strength for the brazed 99.8% alumina. Failures in the 99.8% alumina samples occurred at the braze-alumina interface, while the ...
Irradiation response on the tensile properties of 9Cr-2W steels has been investigated following FFTF/MOTA irradiations at temperatures between 646 and 873 K up to doses between 10 and 59 dpa. The largest irradiation hardening accompanied by the largest decrease in the elongation is observed for the specimens irradiated at 646 K at doses between 10 and 15 dpa. The irradiation hardening appears to saturate at a dose of around 10 dpa at the irradiation temperature. No hardening but softening was observed in the specimens irradiated at above 703 K to doses of 40 and 59 dpa. Microstructural observation by transmission electron microscope (TEM) revealed that the dislocation loops with the a left angle 100 right angle type Burgers vector and small precipitates which were identified to be M_6C type carbides existed after the irradiation at below 703 K. As for the void formation, the average size of voids increased with increasing irradiation ...
Chloride-induced pitting corrosion of stainless steel (Materials No. 1.4301 and 1.4571) was investigated with the aid of chronopotentiostatic tests. Oxide films upon the surface (temper colours), addition of inhibitors (sulphate and nitrate) and temperature were the testing variables. Two different critical pitting potentials have been found, which give information on the potential ranges for stable passivity, latent and stable pitting corrosion. The results only indicate a small effect of Mo content of the material and test temperature. The inhibitors (sulphate and nitrate) have a marked effect. Specimens with a clean surface produced by pickling are markedly more resistant against pitting corrosion than specimens with a yellow temper colour, whereas the difference in corrosion resistance between yellow and blue films is relatively small. The width of the critical potential range for pitting corrosion generally increases with increasing oxide ...
Nitinol has found growing applications in vascular stents, with the recent introduction on the market of a number of new nitinol tubular devices for coronary and peripheral usage. These stents can be produced either through the expansion of a pattern cut on a small tube (pre-cut) or by cutting the deployed design on a tube of a larger size (pre-expanded). The aim of the study was to analyze the differences of properties induced by the two manufacturing methods. For this purpose, differential scanning calorimetry (DSC) measurements were performed on various specimens from the two types of stents. A first set of measurements shows that pre-expanded stents exhibit usual A<->R<->M transformations whereas multi-stage transformations occur for pre-cut stents. Two types of DSC specimens were then prepared for each stent, corresponding to the straight sections and the curved parts of the stent. It is shown that the pre-cut ...
Semiconductive crystalline PZT powders doped with Bi and K were synthesized by hydrothermal reaction at 200{degree}C for 48 hours. The synthesis of the crystalline powders became difficult with an increase in doped amount of Bi and K, and in Zr/(Ti+Zr) ratio. Since substantial amounts of Pb remained in solution after hydrothermal reaction, the addition of Pb in excess of 25% was necessary to obtain the stoichiometric composition of the PZT solid solution. Bi contents in the powders were identical to those in starting materials, while K contents were less than expected ones. The electromechanical properties of the sintered bodies could be precisely measured by an admittance-curve-fitting method. The electromechanical coupling factor and piezoelectric coefficient of the sintered bodies varied with the Bi content like those of specimens prepared by solid state reaction, and showed the maximum values at a given Bi content. However, the change in conductivity with the ...
In relation to coal liquefaction, the effect of inorganic minerals on liquefaction reactivity and the effect of hydrofluoric acid (HF) treatment on organic molecular structure of coals were studied by demineralization of low-rank coals in HCl or HF solution. In experiment, Taiheiyo coal specimen was deashed in HCl solution at 25-70{degree}C for 6 hours while agitating, and in addition, deashed in HF solution. Hydrogenolysis of the deashed coal specimen was conducted using tetralin or methylnaphthalene as solvent under initial hydrogen pressure of 1.96MPa at reaction temperature of 693K for 60min. The experimental results are as follows. The ash content of Taiheiyo coal hardly offers catalysis in hydrogenolysis reaction. Carboxyl group increases in demineralization of coal because of breakage of bridged bonds. Organic structure of coal changes by demineralization in dense HF solution. Change in organic structure of coal by demineralization in ...
Past elastic-plastic fracture studies for leak-before-break (LBB) assessment of low alloy steel pipings have been focused mostly on the behavior of base metals and their weld metals. In contrast, the heat-affected zone (HAZ) of a welded pipe has not been studied in detail primarily because the size of the HAZ is too small to make specimens for mechanical properties measurements. In this study, microstructural analyses, microhardness tests, tensile tests and J-R tests have been conducted as a function of distance from a fusion line and temperature for HAZ materials of SA106Gr.C low alloy piping steels. For the ferrite-pearlite steels such as SA106Gr.C, the HAZ specimens showed a higher yield strength and fracture toughness compared with those of its base metal. These characteristics, despite of grain coarsening, can be explained by cleaner microstructures of HAZ materials with a finer morphology of carbides compared with pearlitic-ferritic base ...
Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the ...
This report summarizes work performed by Argonne National Laboratory on fatigue and environmentally assisted cracking (EAC) in light water reactors from January 1997 to June 1997. Topics that have been investigated include (a) fatigue of carbon, low-alloy, and austenitic stainless steels (SSs) used in reactor piping and pressure vessels, (b) irradiation-assisted stress corrosion cracking of Types 304 and 304L SS, and (c) EAC of Alloys 600 and 690. Fatigue tests were conducted on ferritic and austenitic SSs in water that contained various concentrations of dissolved oxygen (DO) to determine whether a slow strain rate applied during various portions of a tensile-loading cycle is equally effective in decreasing fatigue life. Slow-strain-rate-tensile tests were conducted in simulated boiling water reactor (BWR) water at 288 C on SS specimens irradiated to a low fluence in the Halden reactor and the results were compared with similar data from a control-blade sheath and ...
Tensile specimens of the normalized and tempered fully martensitic steel DIN 1.4914 were helium implanted up to 340 appm within the temperature range 300-720/sup 0/C using a 104 MeV alpha particle beam. The high He/damage ratio of 1850 appm He/dpa allowed to determine the effect of helium on material properties. After irradiation tensile strength and ductility were investigated mainly at test temperatures equal to the irradiation temperatures. While short time irradiations with helium contents up to 100 appm have shown no visible effect on the tensile behaviour at all temperatures investigated, long time irradiations reduced the material strength at irradiation temperatures above about 440/sup 0/C. This irradiation induced softening obscured the predicted minor hardening effect of the observed He-bubbles completely and increases with irradiation time and temperature. The fracture mode of helium-implanted and control specimens is found to remain ...
Specimen strips of pure alpha titanium and beta titanium alloy were exposed to a range of up to 46 deuterium plasma discharges in the Princeton Large Torus Tokamak (PLT) under simulated first wall conditions, and the amount of trapped deuterium in these specimens was measured, using carbon as a calibration standard for trapping. The Deuterium Nuclear Microprobe was used to study the total trapped deuterium and the deuterium depth distribution in the exposed materials before and after annealing at 373 and 423"0K. The Scanning Auger Microprobe was used to identify the effects of surface impurities on the deuterium distribution. Results indicate that about 20 to 40% of the incident deuterium was trapped by the surface and about 90% of the trapped deuterium remained in a 20A carbonaceous film deposited during plasma exposure. Annealing resulted in a gradual loss from the film. These results indicate the importance of impurity film formation which ...
This research involves the development of an analysis which yielded recommendations regarding the plate thickness at which the effects of transverse shear become significant enough to be taken into consideration during vibration testing of composite plates. The specimens designed using this analysis are to be used for the {open_quotes}inverse{close_quotes} problem of determining through-the-thickness elastic constants as well as in-plane elastic constants from modal vibration response data. The effects of transverse shear were studied over the range of practical plate aspect ratios (length to thickness ratios) and mode numbers. Behavior of composite plates ranging from isotropic to highly orthotropic was studied in order to investigate the effects of transverse shear. Orthotropic plates having in-plane dimensions of 254 x 254 mm and thicknesses varying from 10 mm to 80 mm, with free-free edge boundary conditions, were considered. A methodology was developed to use ...
The effect of combustion conditions on conversion of char nitrogen to N2 was studied in the combustion experiment of char obtained by pyrolysis of coal. Char specimen was prepared by holding ZN coal of Chinese lignite in Ar atmosphere at 1123K for one hour. A batch scale quartz-made fluidized bed reactor was used for combustion experiment. After the specimen was fluidized in reaction gas, it was rapidly heated to start combustion reaction. CO, CO2 and N2 in produced gases were online measured by gas chromatography (GC). As the experimental result, under the incomplete combustion condition where a large amount of CO was produced by consuming almost all of O2, no NOx and N2O produced from char were found, and almost all of N-containing gas was N2. At the final stage of combustion, pyridinic-N disappeared completely, and pyrrolic-N decreased, while O-containing nitrogen complexes became a main component. It was thus suggested that O-containing ...
Coal demineralization mechanism and its optimum condition were studied by hydrothermal reaction between Ca(OH)2 and quartz as a coal demineralization model. In experiment, the mixture of powder quartz and Ca(OH)2 water slurry was subjected to reaction in an autoclave under spontaneous pressure at 175-340{degree}C. After dried in N2 gas atmosphere at 105{degree}C, the reaction product was analyzed by X-ray diffraction, thermo-balance and differential thermal analysis. In measurement of quartz conversion, the specimen was analyzed by X-ray diffraction after removal of bound water by heat treatment at 850{degree}C. The mixture of clean coal deashed by NaOH and a fixed amount of quartz was also used as specimen for experiment. As the experimental result, dicalcium silicate hydrate was mainly produced at 175{degree}C, and the product changed into xonotlite through tobermorite by longer treatment at higher temperature. For complete reaction of ...
The effect of the nitrogen uptake in {alpha}-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic {alpha}-Fe phase (50%). The 20% of specimen volume form {alpha}'-Fe and {alpha}''-Fe{sub 16}N{sub 2} phases. The last 30% occupy the {gamma}'-Fe{sub 4}N, ferro- and paramagnetic {epsilon} phases, and {gamma}-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into {alpha}-iron particles which results in the formation of paramagnetic {epsilon}({zeta})-Fe{sub 2}N phase. This phase also dominates the surface of {alpha}-iron ...
The effect of the nitrogen uptake in #alpha#-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic #alpha#-Fe phase (50%). The 20% of specimen volume form #alpha#'-Fe and #alpha#''-Fe_1_6N_2 phases. The last 30% occupy the #gamma#'-Fe_4N, ferro- and paramagnetic #epsilon# phases, and #gamma#-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into #alpha#-iron particles which results in the formation of paramagnetic #epsilon#(#zeta#)-Fe_2N phase. This phase also dominates the surface of #alpha#-iron specimen implanted by nitrogen using ...
The BEATRIX-II irradiation experiment is an in-situ tritium release experiment being carried out in the Fast Flux Test Facility (FFTF) reactor to evaluate the tritium release characteristics of fusion solid breeder materials. A sophisticated tritium gas handling system has been developed to continuously monitor the tritium recovery from the specimens and facilitate tritium removal from the experiment's sweep gas flow stream. The in-situ recovery experiment accommodates two different in-reactor specimen canisters with individual gas streams and temperature monitoring/control. Ionization chambers have been specifically designed to respond to the rapid changes in the tritium release rate at the anticipated tritium concentrations. Two ceramic electrolysis cells have proved effective in reducing the moisture in the gas streams to hydrogen/tritium. A tritium getter system, capable of reducing the tritium level by a factor greater than 4000, ...
For a reliable design against fatigue failure of high-temperature components of different types of the heat resistant material Alloy 800, verified parameters of the low-cycle fatigue (LCF) behaviour are required. These parameters were obtained by a scatterband evaluation of the results of low-cycle fatigue tests, using a computerized data bank which includes all available actual data sets. The results of the evaluation are presented as mean fatigue curves with the upper and lower boundary limits of the scatterbands. For the type Alloy 800 in the recrystallization annealed condition, the results cover a temperature range from 20 to 750deg C; for the solution annealed types they cover a temperature range from 20 to 950deg C. Specimens tested in HTR helium at high temperatures had longer lives than specimens tested in air. This effect was represented quantitatively by the ratio of the total strain ranges from tests in HTR helium and air as a ...
A personal computer based single specimen unloading technique has been demonstrated using a nuclear grade pressure vessel material, A533B Class I steel, and an #alpha#-#beta# titanium alloy, CORONA-5. Experimental parameters investigated in the case of steel include the effect of test temperature, loading rate and neutron irradiation. Results revealed the effect of dynamic strain aging (DSA) as a drop in the critical crack initiation fracture toughness (Jsub(q)); the minimum in Jsub(q) shifts to higher temperatures at higher test speeds as predicted from DSA models. In CORONA-5, the effects of microstructure and heat treatment for two different sizes of equiaxed #alpha# morphology in a #beta#-matrix heat treated to different yield strengths were investigated. It is found that the observed higher values of Jsub(q) and tearing modulus result from a greater tortuosity of the crack path and ease of crack blunting. The largest increase in Jsub(q) occurred in fine ...
Purpose: The lifelong persistence of foreign bodies within the arteries may contribute to restenosis. Thus,biodegradable devices might decrease recurrence rates. Methods: Eleven polyhydroxybutyrate biodegradable stents and 13 tantalum stents were implanted into the iliac arteries of New Zealand white rabbits for up to 30 weeks. After killing the animals,the specimens were harvested, fixed in formalin, processed in paraffin,and stained. Results: Polyhydroxybutyrate instigated intense inflammatory and proliferative reactions with an increase in collagen (2.4- to 8-fold vs native segments), thrombosis and in-stentlumen narrowing (375.5-606.6 mm vs 655.6 #+-# 268.8 mm in native segments). The elastic membranes were destroyed in all specimens. The tantalum stents increased the in-stent lumen progressively (769.7 #+-# 366.6 mm vs 1309.9 #+-# 695.3 mm),penetrated the external elastic membrane, and increased mural collagen content (6- to 8.6-fold vs ...
An overall systems approach has been applied to develop action plans to support the retrieval and immobilization waste disposal mission. The review concluded that the systems and infrastructure required to support the mission are known. Required systems are either in place or plans have been developed to ensure they exist when needed. The review showed that since October 1996 a robust system engineering approach to establishing integrated Technical Baselines, work breakdown structures, tank farm structure and configurations and work scope and costs has been established itself as part of the culture within TWRS. An analysis of the programmatic, management and technical activities necessary to declare readiness to proceed with execution of the mission demonstrates that the system, people and hardware will be on line and ready to support the private contractors. The systems approach included defining the retrieval and immobilized waste disposal mission requirements and evaluating the ...
Since 1975 All Volatile Treatment (AVT) has been the preferred method for controlling the secondary system operating environment in Westinghouse PWR plants. However, since AVT provides no buffering action against corrodent species present in the water as trace contaminants, utilities have initiated programs which combine control of contaminant ingress with total steam generator sludge management. The earliest applications of boric acid, to control denting type corrosion, began in 1978 and have continued up to the present time. Boric Acid has also been added as an inhibitor for SCC/IGA type corrosion since 1985. There are now approximately 30 plants operating with boric acid or boric acid/morpholine chemistry in the secondary system, and a growing number of plants where morpholine is being used as an additive to maintain pH and reduce iron transport attributable to erosion/corrosion. The impact of these modifications in the operating chemistry environment are examined for their ...
This paper presents the present status of R and D activities on plasma facing components for fusion reactors, such as International Thermonuclear Experimental Reactor (ITER) and fusion demonstration reactor (DEMO). The plasma facing components (PFCs) as typified by divertor and first wall components are subjected to high heat flux and particle flux from fusion plasma. It is essential for these components to have sufficient heat removal capability and robust structure against those loadings. JAEA has been carried out to develop the ITER-PFCs which consist of copper alloys and armor materials with high thermal conductivity, such as carbon fiber composites, tungsten and beryllium. The demonstration of the thermomechanical performance of the ITER-PFCs by using mock-ups has successfully been made under close mutual cooperation between the participant countries of ITER. Currently, the activity on the development of the ITER-PFCs is in a qualification phase prior to the ...
Reactor pressure vessel (RPV) steels are subjected to neutron irradiation at a temperature of about 290 deg C. This radiation exposure alters the mechanical properties, leading to a shift of the brittle-to-ductile transition temperature toward higher temperatures and to a diminution of the rupture energy as determined by Charpy V-notch tests. This radiation embrittlement is one of the important aging factors of nuclear power plants. U.S. NRC recommended the basic requirements for the determination of the pressure vessel fluence by regulatory guide DG-1025 in order to reduce the uncertainty in the determination of neutron fluence calculation and measurements. The determination of the pressure vessel fluence is based on both calculations and measurements. The fluence prediction is made with a calculation and the measurements are used to qualify the calculational methodology. Because of the importance and the difficulty of these calculations, the method`s ...
The R&D in satellite communications in Korea has been driven mainly by KCC (Korea Communications Commission) but in a small scale compared to Korea space development program organized by MEST (Ministry of Education, Science and Technology). Public and civilian satcom sector R&D has been led mainly by ETRI with small/medium companies contrary to rare investment in private sector while military sector R&D has been orchestrated by ADD with defense industry. By the COMS (Communication, Ocean and Meteorological Satellite) experimental Ka-band payload, Korea pursues a space qualification of own technology for national infrastructure evolution as well as industrialization of space R&D results. Once COMS launched and space qualified in 2009, subsequent application experiments and new technology R&D like UHDTV will entail service and industry promotion. The payload technology is expected for the next Korean commercial satellites or for new OBP ...
Piping systems transporting high-pressure fluid will release a large amount of energy, leading to whipping of the broken pipe as well as impingement of the ejecting fluids on adjacent structures if they fracture unstably. Postulation of such an event in design of piping systems in nuclear power plants often requires various counter measures such as installation of pipe whip restraints or jet impingement shields to prevent such damage. One of the approaches to justify exclusion of unstable fracture from the design conditions is leak-before-break (LBB) analysis. In order to demonstrate LBB behavior, it is necessary to prove that in the presence of a part-through wall flaw in the pipe, this flaw will not grow through the wall under fatigue loading and is stable (level 2 LBB) and that the leak of fluid through the penetration is detected by leak detection systems before unstable fracture occurs (level 3 LBB). If this can be demonstrated in plant design, significant reduction of ...
The competitiveness of a new nuclear plant vs. a new oil or gas fired combined cycle plant or a coal fired plant in East-Asia, is reviewed in the paper. Both the nuclear and the fossil fired plants are evaluated as either utility financed or independent power producer (IPP) financed. Two types of advanced light water reactors (ALWRs) are considered in this paper, namely evolutionary ALWRs (1200 MWe size) and passive ALWRs (600 MWe class). A range of capital and total generation costs for each plant type is reported here. The comparison centers on three elements of overall competitiveness: generation costs, hard currency requirements, and employment requirements. Each of these aspects is considered perspective. Year-by-Year generation cost history over the plant lifetime is shown in some cases. It is found here that a utility financed evolutionary and passive ALWRs are broadly competitive with an IPP financed gas fired combined cycle plant and are more economic than oil fired combined ...
Using standards on phenol-formaldehyde resin base for assaying-activation analysis of geological specimens for gold and silver has bee the advantage of uniformly distributing Au and Ag in spesimens and possible preparing tablets of practically any form or size. The validity and accuracy of these standards have been studied for the cases of short irradiation. Conventional point standards were used as reference standards. The experiments carried out have shown that tablet resol standards are suitable for a mass assaying-activation analysis for gold and silver at practically any concentrations.
Generally, Hardening and irradiated brominating phenomena are occurred in the reactor vessel under operation conditions by atomic cavities and creation of impurity atoms which are led by high fast neutron flux. To assure the mechanical integrity of pressure vessel until the end of power plant life after monitoring the sample specimens on the vessel inside, a series of tests is performed over the retrieved surveillance capsule to examine the changes according to the plant operation in accordance with regulations. Monitoring surveillance capsules attached to neutron shield wall of outer core are consists of impact sample, tensile sample and temperature monitor
Mg-3%Al-1%Zn (AZ31) alloy was subjected to ECAE processing at 523 and 573 K. Microstructure observation and texture analysis were carried out using optical microscope and SEM-EBSD technique in order to investigate the process of microstructural changes including texture development during ECAE processing. Grain refinement during ECAE processing is enhanced by dynamic continuous recrystallization. The texture of the ECAE-processed AZ31 alloy specimens change with ECAE processing temperature, and the textural changes relate to deformation mechanisms that change with ECAE processing temperature. (orig.)
17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.
The behavior of the superconducting transition temperature T/sub c/ of single-crystal and polycrystalline V_3Si was investigated as a function of low-fluence neutron irradiation. It is found that the initial degradation of T/sub c/ is sample-dependent, some specimens showing no degradation in T/sub c/ up to a fluence of 2 x 10"1"8 n/cm"2. This and many other earlier observations on low-fluence behavior are explained in terms of a recently proposed model of radiation damage in A-15 compounds.
The objective of this study is to comprehend the basic structural characteristics of box shaped mixed structures proposed for a future nuclear reactor building structure. Specimens of reinforced concrete precast panel walls of the mixed structures were prepared using ultrahigh strength materials. Two bending shear tests were conducted with a parameter of the quantity of reinforcement bars. The results include: (1) Relationship of shear stress and the angle of the structure, and (2) Failure mode. (author)
Nuclear grade production tubing of Alloy 600 was evaluated for stress corrosion cracking (SCC) susceptibility in high purity water at 365, 345, 325, and 290 C. Reverse tube U-bend specimens provided crack initiation data and constant extension rate tests were employed to determine the crack velocities experienced in th crack propagation stage. Initial results indicate that a linear extrapolation of data received from high temperature tests can be used to predict the service life of steam generator tubing that has been plastically deformed or is continually deforming by ''denting.''.
Considering the hardware characteristics of the laser-induced plasma X-ray source and the limitations of the conventional cone-beam reconstruction algorithm, a general cone-beam reconstruction algorithm has been developed at our laboratory, in which the motion locus of the X-ray source is an arbitrary curve corresponding to at least a 2{pi} continuous horizontal angular displacement in the coordinate system of the specimen. The preliminary simulation shows that the general cone-beam reconstruction algorithm consistently results in visually satisfactory images.
Considering the hardware characteristics of the laser-induced plasma X-ray source and the limitations of the conventional cone-beam reconstruction algorithm, a general cone-beam reconstruction algorithm has been developed at our laboratory, in which the motion locus of the X-ray source is an arbitrary curve corresponding to at least a 2{pi} continuous horizontal angular displacement in the coordinate system of the specimen. The preliminary simulation shows that the general cone-beam reconstruction algorithm consistently results in visually satisfactory images.
Radiation-initiated polymerization of styrene and acrylic acid in poplar wood were investigated for the preparation of wood-polymer composites. The direct irradiation method was applied to the monomer adsorbed poplar wood specimens. 8000 Ci "6"0Co source at a dose rate of about 0.4 Mrad/h was used. Furthermore the effects of carbon tetrachloride, methanol, dioxane and acrylonitrile on styrene polymerization were investigated and the reaction rates were calculated for each case. The influence of CCl_4 (10%) on acrylic acid polymerization in poplar wood was also determined. (author).
Periosteal Ewing's sarcoma is an uncommon, but well documented origin of this malignant condition with radiography signs, different from intramedullary growing tumours. Imaging modalities like CT or MRI supply proof of macroscopically intact endosteal cortical surface and free medullary cavity in long bones affected by this periosteal type of malignancy. Definite confirmation is valid after a careful microscopic investigation of the resected specimen. The prognosis of this type of Ewing's sarcoma may be favourable than that of the central type. Early diagnosis and therapy are thus essential. A clinical survey of six observations is given. (orig.).
Presented are the results of the investigation of the kinetics and micromechanism of the failure in impact bending of oriented-crystallized specimens having the eutectic composition Ni_3Al-Ni_3Nb and of the bimetal composed of 45 steel + M3 copper. The failure kinetics was studied by high-speed filming, whereas the fractures were studied by electron fractography. The particularities of the failure of the laminar-type composite materials were found. Analyzed was the effect of the kinetic factors and the mechanism of failure upon its energy consumption.
In this paper we studied the behavior of commercially pure niobium immersed in molten aluminum. The experiments were carried out 800 and 900 deg C during 2 to 128 hours. Chemical and metallographic analyses, as well as microhardness measurements of the niobium specimens were accomplished. An increase of niobium content in the aluminum bath with time was observed. Metallographic observations revealed the formation of Nb Al{sub 3} external intermetallic compound. During dissolution, fragments of this compound settled at the bottom of the crucible. This behaviour was also observed at 900 deg C, nevertheless with higher intensity. (author) 10 refs., 5 figs., 3 tabs.
Some results on mechanical property study of copper and titanium subjected to impact load and next to neutron irradiation are presented. It was shown that shock wave influence involves a substantial shape change of the stress-strain diagram and of respective mechanical characteristics. Yield- and ultimate strength were substantially increased, as well as hardness with a considerable drop of plasticity. Also a heat stability of copper and titanium specimens was studied after being treated with shock-waves and neutron radiation. Results are given of electron microscope study of titanium structure sfter explosion hardening, which caused decomposition of hydride segregations in titanium and increased dislocation density.
A study was made of the variation in strength characteristics of group IV transition metal carbon nitrides alloyed with carbides or group V metal nitrides. A complex solid solution of titanium-niobium carbonitride was preliminarily synthesized to a homogeneous equilibrium state and then crushed. The calculated quantity of binder metal was added as elemental powders, the mixture was vibration ball milled in ethanol and the plasticized charge was used to press experimental specimens for mechanical testing. The studies showed that the high-temperature strength properties of the new cermet are superior to standard type KNT. The material is thus promising for use in the manufacture of tools. 8 references, 3 figures.
Pulmonary embolism complicated by transcatheter arterial chemoembolization (TACE) in known to be due to the use of large amount of lipiodol as an embolic agent. To our knowledge, massive tumoral pulmonary embolism following TACE and confirmed by surgery has not been described in the literature. In this report, we detail the cas of a 49-year-old man in whom cyanosis and hypotension developed abruptly on the day of TACE.. Chest CT revealed diffuse low-attenuated lesions in both pulmonary arteries. Histopathological specimens after emergent pulmonary arterial embolectomy confirmed the presence of massive tumor emboli of hepatocellular carcinoma.
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N-curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle-fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonitrides or Aluminium Oxides. A model was developed to describe the influence of the magnitude of these inclusions on the lifetime. A weakest link model, using the statistical distribution of inclusions and surface flaws, was used to describe the fatigue limit. (orig.)
Life management system is based on the valid nowadays in Estonian power plants regulation documentation. The system allows to estimate stress distribution in components, find computational assessment of cumulated creep damage, determine when and where it is necessary to cut off the particular number of microsamples or take replicas. Finally, the real metal condition may be assessed on the basis of metallographic specimen research and reasonable 3-R decision - run, repair, replacement - made on further component use. (orig.) 6 refs.
The quality of the end product from andrology services continues to lack consistency and in some cases fails to meet the needs of the end users (patients or clinicians). Results of external quality assessment (EQA) schemes continue to show unacceptably wide variation for the results of a single specimen. Some laboratories are able to show that the results of semen analyses relate to both natural and assisted pregnancy and are therefore useful in the management of the infertile couple, whereas others claim that their value is limited to the identification of severe male factor infertility. With wide variation in standardisation of methodology, levels of staff training and quality assurance, it is entirely understandable that such discrepancies persist. The following article proposes that Qu...
Aluminium-lithium extrusions possess high inhomogeneity of properties across the cross section. Mechanical properties such as R{sub p0,2}, R{sub m} and hardness, but also fatigue properties, change their value in dependence with the cross section position where test specimens were taken. Positions, where extreme values of properties are measured, are characteristic for a given extrusion shape. The positions with different properties have different structure and texture. Properties and structure inhomogeneity is affected mainly by extrusion shape and heat treatment parameters. (orig.)
The oil palm Elaeis guineensis is usually attacked by pests, particularly, defoliating caterpillars. Between 2004 and 2006 a stinkbug predator (Asopinae) was registered preying on caterpillars of Brassolis sophorae L., Opsiphanes invirae Hubner (Lepidoptera: Nymphalidae) and Sibine spp. (Lepidoptera: Limacodidae), reducing their populations in commercial oil palm plantations in the State of Para, Brazil. Specimens of the natural enemy were collected, mounted, and identified as Alcaeorrhynchus grandis (Dallas) (Hemiptera: Pentatomidae), corresponding to the first report of the occurrence of this stinkbug attacking defoliating caterpillars of oil palm in Brazil. (author)
author.The chemical and mechanical properties of S235jr structural low carbon mild steel were tested and reported for specimens collected from the Lebanese steel market. European and American standards were presented as references and compared with the achieved results. Discussion was conducted to show the similarities and differences between S235JR steel samples and standard requirements. Some of the reasons for such differences were discussed. A database was furnished through this work for the public and mainly for the Lebanese Standard Organization LIBNOR to easily adopt and implement a standard that has been tested in Lebanon concerning the hot rolled low carbon structural steels
We explore autofluorescence endomicroscopy as a potential tool for real-time visualization of epithelial tissue microstructure and organization in a clinical setting. The design parameters are explored using two experimental systems--an Olympus Medical Systems Corp. stand-alone clinical prototype probe, and a custom built bench-top rigid fiber conduit prototype. Both systems entail ultraviolet excitation at 266 nm and/or 325 nm using compact laser sources. Preliminary results using ex vivo animal and human tissue specimens suggest that this technology can be translated toward in vivo application to address the need for real-time histology.
Two species of wood, viz. Haldu (Adina Cordifolia) and Jamun (Syzygium Cumini) were vacuum-impregnated with two styrene-based monomer systems and polymerized in situ with gamma radiation from a cobalt-60 source. The electrical conductivity of these specimens was determined at various polymer loadings under dry conditions, after wetting and after wet recovery as per ASTM standards. The water absorption characteristics are also presented. The results are discussed with special reference to the role of water. Potential applications are also discussed. 7 figures.
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.
This paper deals with the pitting corrosion of evaporators in the liquid - radwaste system of nuclear power stations. Corrosion testrs were conducted by the anodic polalization of specimen in the chloride solution. (1) The initiation of the pitting in SUS 304, SUS 316 stainless steels was inhibited by addition of NaOH and H_3BO_3, however, these addition had no effect on the pitting propagation. (2) Inconel 625 had the resitivity against the pitting initiation superior to that of stainless steels, but this was not necessarily in the case of the pitting propagation. (3) It is noticed for pitting prevention that the environmental and material effect on the pitting initiation differed from that on the pitting propagation. (author).
Creep properties of modified 9 Cr-1 Mo steel, an alloy significantly improved in elevated-temperature strength over 2 1/4 Cr-1 Mo and other similar alloys, are presented here. Data are primarily on material in the normalized and tempered condition. Effects of variables such as isothermal annealing treatment, cold work, normalizing temperature, tempering temperature, notch, and biaxial stress state have also been examined. Data analysis and comparisons have shown that modified 9 Cr-1 Mo alloy is very insensitive in response to several material variables, heat treatments, and specimen design variables.
During 1983, Oak Ridge National Laboratory continued a study of materials performance at the Wilsonville, Alabama, Advanced Coal Liquefaction Research and Development Facility. Materials performance was evaluated by exposure and analysis of corrosion coupons and U-bend specimens, chemical analysis of related process streams, and ultrasonic determination of the thickness of walls of various components. The results of these studies are useful to current plant operators and to designers of future large-scale plants. 18 references, 4 figures, 12 tables.
Computer processing was adopted to pick up significant signals from the undefined Moessbauer spectra. A program, by which smoothing and curve fitting was made possible, was devised and applied to the analysis of the Moessbauer spectra of "5"7Fe enriched iron and other specimens. Although this processing sometimes distorted the absorption peaks, it was quite effective for elimination of noise and finding of exact positions of absorption peaks. Availability of the processing was demonstrated by several examples obtained for "5"7Fe enriched iron, natural iron, calcined ferric oxyhydroxides, red mud residue and its calcined product. (auth.).
Abstract The white sea bream, Diplodus sargus (Teleostei, Sparidae), is a species with a high commercial importance in Mediterranean aquaculture. There is currently little information available about the genetic characteristics of cultured populations. In this survey, we have developed eight polymorphic microsatellites for the white sea bream using an enriched genome library protocol. All of them were polymorphic in the 67 individuals tested, 32 of which were wild specimens, and 35 were individuals from a captive F1 broodstock. These markers can potentially be useful tools for use in population genetic studies.
The study is concerned with the combined effect of high pressure and shear strain on the properties of the A-15 intermetallics Nb3Sn and Nb3Al0.75Ge0.25. The properties discussed are the superconducting transition temperature, the width and intensity of the X-ray diffraction lines, and the width and shape of the Mossbauer absorption lines. It is shown that the combined effect of high pressure and shear strain leads to an intense generation of defects in polycrystalline specimens; the size of the ordered regions does not exceed 300 A even under the least severe conditions. 5 references.
The susceptibility of CHN35VT-VD and 08CH18N10T stainless steels to stress corrosion cracking in water environment, simulating water solution found in threaded holes, was investigated using rising load line displacement tests of precracked C(T) specimens. To judge the role of oxidant on stress corrosion cracking of both stainless steels, the effect of dissolved oxygen content (fully deaerated water, water aerated at the beginning of the test) was studied. 7 refs.
We present a case of cerebral aspergillosis in an immunocompetent patient. The MRI signal characteristics were compared with the histologic findings. Irregular low-signal zones were demonstrated between the wall of the abscess and the central necrosis on T2-weighted images; the pathology specimen revealed concentrated iron in these transitional zones but no hemosiderin. Iron is an essential element for the growth of fungal hyphae. The low-signal zones may represent the areas where there was active proliferation of aspergillus, and the unique location of the low signal may be a helpful imaging characteristic for the diagnosis of an aspergillus abscess. (orig.)
The method of aluminium metal activation by liquid eutectics Ga-In (70:30) and Ga-In-Sn-Zn (60:25:10:5) is developed. Subsequent dispersion of the obtained specimens up to a particle size of >0.5mm leads to the drastic interaction of aluminium powder and water with evolving hydrogen. In the present work the oxidation rate of activated aluminium and water is investigated depending on eutectic composition, reaction temperature, and powder particle size. The mechanism of the main eutectic's components influence on the reacting ability of aluminium is discussed. (author)
Cyclic voltammograms of SUS 304 stainless steel in various neutral solutions such as Na/sub 2/SO/sub 4/ at high temperature were measured, as a successive study to previous report in which effects of temperature and pH on polarization behavior of stainless steel were studied. In this measurement Ag/AgCl reference electrode and platinum counter electrode were used in a static autoclave lined with inconel. Passive films formed in various conditions were analysed by electron diffraction and Auger spectroscopy. Results obtained were compared with anodic behavior of iron, chromium and nickel and with thermodynamical stabilities of their compounds. The main results are summarized as follows. (1) Stainless steel shows such electrochemical behavior as active dissolution, passivation and transpassivation in a deaerated neutral solution at 250/sup 0/C after fully reductive treatment of the specimen. In air-saturated solution, the peak of active dissolution is not observed. ...
Nature of tube degradation was studied in support of horizontal steam generator lifetime calculations. Experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K(ISCC), and the crack growth rate were made to predict evolution of damage in tube walls. Experimental results were compared with in-service inspections experience. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that material of SG (steam generator) tubes is sensitive to ...
Nature of tube degradation was studied in support of horizontal steam generator lifetime calculations. Experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K(ISCC), and the crack growth rate were made to predict evolution of damage in tube walls. Experimental results were compared with in-service inspections experience. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that material of SG (steam generator) tubes is sensitive to ...
Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington have focused on developing and evaluating the reliability of nondestructive testing (NDT) approaches for coarse-grained stainless steel reactor components. The objective of this work is to provide information to the United States Nuclear Regulatory Commission (NRC) on the utility, effectiveness and limitation of NDT techniques as related to inservice testing of primary system piping components in pressurized water reactors. We examined cast stainless steel pipe specimens containing thermal and mechanical fatigue cracks located close to the weld roots and having inner and outer diameter surface geometrical conditions that simulate several water reactor primary piping configurations. In addition, segments of vintage centrifugally cast piping were examined to characterize the inherent acoustic noise and scattering caused by grain structures and to determine the consistency of ...
The objectives of this study were to evaluate the performance of the NucliSens easyMAG platform for nucleic acid extraction from different clinical specimens compared to NucliSens miniMAG platform and manual QIAGEN extraction. The NucliSens easyMAG and the NucliSens miniMAG showed equal performance on 215 throat swabs since real-time nucleic acid sequence-based amplification scored the same samples positive for Mycoplasma pneumoniae (n=9) and Chlamydia pneumoniae (n=5) RNAs, although internal control RNA was slightly better detected with the NucliSens easyMAG (99.3% versus 96.8%). NucliSens easyMAG extracted nucleic acids more efficiently (higher recovery and/or fewer inhibitors) compared to QIAGEN extraction by showing, on average, lower Ct values in real-time LightCycler PCR, although 4 individual specimen out of 45 were found positive only with QIAGEN. For nine M. pneumoniae-positive throat swabs, the mean difference in Ct values between ...
Full text of publication follows: Fission neutron irradiation to steels doped with isotope boron-10 is frequently conducted to study effects of the helium production on mechanical properties. The intrinsic mechanical properties of F82H steels could have been changed due to the boron doping. Recently, we reported that co-doping with boron and nitrogen to F82H (F82H+B+N) improved the mechanical properties of F82H doped only with boron. The mechanical properties of F82H+B+N are successfully comparable with the non-doped F82H before irradiation. In order to evaluate the effects of initial microstructure and helium production on radiation hardening, F82H and F82H+B+N were irradiate d Specimens used in this study were standard F82H martensitic steels, F82H steels doped with 60 mass ppm 10B and 200 ppm N (F82H+10B+N) and F82H steels doped with 60 mass ppm 11B and 200 ppm N (F82H+11B+N). Initial microstructures were changed by tempering conditions, and the tempering ...
Atterberg limits, free swell, and hydraulic conductivity tests were conducted to assess how wet-dry cycling affects the plasticity and swell of bentonite, and the hydraulic conductivity of geosynthetic clay liners (GCLs) hydrated with deionized (DI) water (pH 6.5), tap water (pH 6.8), and 0.0125-M CaCl{sub 2} solution (pH 6.2). The plasticity of bentonite hydrated with DI water increased during each wetting cycle, whereas the plasticity of bentonite hydrated with tap water and CaCl{sub 2} decreased during each wetting cycle. Wet-dry cycling in DI water and tap water had little effect on swelling of the bentonite, even after seven wet-dry cycles. However, swelling decreased dramatically after two wetting cycles with CaCl{sub 2} solution. Hydraulic conductivity of GCL specimens remained low during the first four wetting cycles ({approximately}1 x 10{sup {minus}9} cm/s). However, within five to eight cycles, the hydraulic conductivity of all ...
Discussions were given on mullite/SiC composite ceramics as to crack size dependence of their crack healing behavior, and high-temperature strength properties. Test specimens used in the experiment are sinters of mullite powder added with SiC powder at 20% by volume, and hot-pressed under conditions of a sintering temperature of 1650 degC, time of four hours, and a pressure of 35 MPa. In the experiment, a pre-crack was introduced at the center of a test specimen by using a Vickers hardness meter, and a heat treatment was performed in atmosphere at 1300 degC for one hour. A four-point bending test was conducted in atmosphere as a strength test. Conditions in test specimens were investigated by using SEM observation, a laser microscope and X-ray diffraction. The following findings were obtained as a result of the experiment: the bending strength for the pre-cracked material is about 140 MPa against that of a smooth material ...
Red mud is a solid waste produced in the process of alumina extraction from bauxite. In this paper, recovery iron from Bayer red mud was studied with direct reduction roasting process followed by magnetic separation, and then building materials were prepared from alumosilicate residues. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery efficiency of iron were carried out. The optimum reaction parameters were proposed as the following: ratio of carbon powder: red mud at 18:100, ratio of additives: red mud at 6:100, roasting at 1300 deg. C for 110 min. With these optimum parameters, total content of iron in concentrated materials was 88.77%, metallization ratio of 97.69% and recovery ratio of 81.40%. Then brick specimens were prepared with alumosilicate residues and hydrated lime. Mean compressive strength of specimens was 24.10 MPa. It was indicated that main mineral phase transformed ...
We aim to examine the spectrum of bacteria causing corneal infections and their antibiotic susceptibility patterns. This will serve as a guideline for empiric therapy of corneal infections. We conducted the study over a period of 18 months from March 2001 through December 2002 in King Abdul-Aziz University Hospital, Riyadh, Kingdom of Saudi Arabia. Corneal specimens taken from 200 patients were inoculated directly onto different types of media. The isolates were identified and then tested against the appropriate topical or systemic antibiotics. Sixty-seven (33.5%) of the total specimens were culture positive and 133 (66.5%) were culture negative. Fourteen (7%) of these showed organisms in the Gram stained smears and correlated well with the culture reports. Of the 67 positive cultures, 53 (79.1%) were Gram-positive bacteria mostly coagulase-negative Staphylococci 29 (43.3%) followed by Streptococcus pneumoniae (S. pneumoniae) 13 (19.4%). Among ...
This paper reports the results of a fine-probe EDS microanalytical study of cellular precipitation in a Cu-Ti binary alloy. Compositional profiles across the solute depleted Cu-rich FCC lamellae and the Cu_4Ti lamellae within isothermally formed cellular colonies were measured in a FEG-TEM from thin-foil specimens prepared by conventional electropolishing and by a technique using a Ga"+ focused ion-beam (FIB). The Cliff-Lorimer ratio method, with an absorption correction, was employed to quantify the compositions. Two FIB samples were prepared with different orientations of the lamellae with respect to the ion-milling direction. The compositional profiles across the Cu-rich FCC lamellae and the Cu_4Ti compound lamellae in both the FIB-prepared samples and the electropolished sample were, within experimental error, numerically equivalent. The composition of the Cu_4Ti compound phase lamellae was very close to the ideal stoichiometric composition of 20 at% Ti. It is ...
Purpose: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. Patients and methods: The ankle joints of four fresh cadaver feet were imaged on a 1.5 T MR-unit in the coronal plane. Standard T{sub 1}-weighted spin echo (SE) and a T{sub 1}-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: Without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic specimens as the gold standard expressing the difference as a percentage value. On ...
The problem of model selection arises in a number of contexts, such as subset selection in linear regression, estimation of structures in graphical models, and signal denoising. This paper generalizes the notion of "incoherence" in the existing literature on model selection and introduces two fundamental measures of coherence---termed as the worst-case coherence and the average coherence---among the columns of a design matrix. It utilizes these two measures of coherence to provide an in-depth analysis of two variants of a simple one-step thresholding (OST) algorithm for model selection and proves that OST is feasible for model selection as long as the design matrix obeys an easily verifiable property. One of the key insights offered by the ensuing analysis in this regard is that if the design matrix has reasonably small worst-case and average coherence then OST performs ...
Long-term divergent selection for low or high body weight from the same founder population has generated two extremely divergent lines of chickens, the high- (HWS) and low-weight (LWS) selected lines. At selection age (56?days), the lines differ by more than nine times in body weight. The HWS line chickens are compulsive feeders, whereas in the LWS line, some individuals are anorexic and others have very low appetite. Previous studies have implicated the central nervous system and particularly the hypothalamus in these behavioural differences. Here, we compared the mRNA expression in hypothalamus tissue from chickens on day?4 post-hatch using oligonucleotide arrays and found that the divergent selection had resulted in minor but multiple expression differences. Differentially expressed gen...
Object: To smoothly control automatic water supply for realizing stable operation of a nuclear reactor by providing a flow rate limiting signal selection circuit and a preferential circuit in a water supply control device for a nuclear reactor wherein the speed of a recirculation pump may be changed in two-steps. Structure: Opening angle signals for a water supply regulating valve are controlled by a nuclear reactor water level signal, a vapor flow rate signal and a supplied water flow rate signal through an adder and an adjuster in response to a predetermined water level setting signal. When the water in the reactor is maintained at a predetermined level, a selection circuit receives a water pump condition signal for selecting one of the signals from a supplied water rate limiting signal generator generating signals for indicating whether one or two water supply pumps are operated. A low value preferential circuit passes ...
The authors present the emitter efficiency results for the thin film 25 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) selective emitter from 1000 to 1700 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns) and used to calculate the radiative efficiency. The radiative efficiency and power density of rare earth doped selective emitters are strongly dependent on temperature and experimental results indicate an optimum temperature (1650 K for Ho YAG) for thermophotovoltaic (TPV) applications.
Single and selective pole tripping schemes may be used to maintain a desired level of system integrity while minimizing transmission line expenditures. In general, these schemes will be most effective on those portions of the system where relatively few interconnections exist. While selective pole tripping may superficially appear to provide more margin than single pole schemes in the preservation of system stability, it seems unlikely that in those actual applications where single pole tripping is warranted that selective pole tripping will provide any significant advantages.
For the selective extraction of radionuclides from nitrate media, the extractabilities of organo-poly-phosphine poly-oxides were examined in the form of impregnated resins. It was found that the extractability of 1,1,3,5,5-pentaphenyl-1,3,5-tri-phospha-pentane trioxide (PPTPT) for U(VI) is quite unusual with very high values at both low and high concentrations of nitric acid, which is not observed for other types of extractants. Thus, this extractant might be promising for the selective extraction of U(VI) in very high concentrations of HNO3. (authors)
High-resolution spectroscopy of 13 bright red giants and Ba stars shows selective enhancement of Ba in three of them, HD 65699 (Ba 2), ..cap alpha..TrA (K4 III), and epsilonPeg (K2 Ib). Infrared spectra available for HD 65699 show that Sr is enhanced, too. This selective enhancement is discussed in terms of a modified s-process which converts some of the pre-existing r- and s-process matter into the magic nuclei /sup 88/Sr and /sup 138/Ba.
The transverse modes of a submillimetre laser cavity that contains waveguides and open parts were studied theoretically and experimentally with the purpose of finding methods for mode selection. Two methods based on the filtering of the Fourier spectra of the waveguide modes and the use of their interference were substantiated numerically and realised in experiment. Special attention was paid to the mode selection in tunable lasers. Scaling laws allowing one to use the obtained results in a wide range of the cavity parameters and wavelengths are presented. (laser applications and other topics in quantum electronics)
A method for analyzing the experimental results of coal liquefaction reactions which is applicable to a number of aspects of coal liquefaction research and process control, including rapid selectivity and performance screening for catalysts; correlation of laboratory results with process parameters; and optimization of product yield with plant process conditions is described here. Ternary diagrams of product/by-product distributions for the coal liquefaction using Co/Mo catalysts combined with a hyperbolic relationship for the conversion of various hydrocarbon fractions can be used for catalyst screening. A hydrogen consumption diagram used to provide a more significant selectivity test than the hyperbolic correlation is also included. (BLM)
Oxidation of propylene with oxygen, air and a mixture of nitrogen?oxygen in a barrier discharge is investigated. The selectivity towards formation of propylene oxide in pure oxygen is shown to be as high as 45 wt% and the propylene conversion ratio is found to be 12.9 wt%. In the oxidation with air, the propylene oxide selectivity is 23 wt%, while the conversion is 7.5 wt%. The values of propylene conversion and selectivity towards formation of propylene oxide in a barrier discharge are consistent with those obtained by the thermocatalytic methods for production of propylene oxide.
In this paper, it is suggested that the selection method of optimal parameter of power system stabilizer (PSS) with robustness in low frequency oscillation for power system using real variable elitism genetic algorithm (RVEGA). The optimal parameters were selected in the case of power system stabilizer with one lead compensator, and two lead compensator. Also, the frequency responses characteristics of PSS, the system eigenvalues criterion and the dynamic characteristics were considered in the normal load and the heavy load, which proved usefulness of RVEGA compare with Yu's compensator design theory. (author). 20 refs., 15 figs., 8 tabs.
A temperature gradient across a thick ({ge}.1mm) film selective emitter will produce a significant reduction in the spectral emittance from the no temperature gradient case. Thick film selective emitters of rare earth doped host materials such as yttrium-aluminum-garnet (YAG) are examples where temperature gradient effects are important. In this paper a model is developed for the spectral emittance assuming a linear temperature gradient across the film. Results of the model indicate that temperature gradients will result in reductions the order of 20{percent} or more in the spectral emittance. {copyright} {ital 1997 American Institute of Physics.}
This paper presents an analysis of the performance of a selective emitter using small particles of rare earth compounds stable at high temperatures in a low emittance inert gas stream. An expression for the spectral emissive power excluding radiation scattering was derived to include the radiation in the emission band, produced by electronic transitions of the rare earth ion, and the continuum radiation outside the emission band produced by the rare earth host. Preliminary results suggest that a selective emitter based on suspended rare earth oxide particles will have high efficiency and merits further experimental investigation. {copyright} {ital 1996 American Institute of Physics.}
Sep 1, 2011 ... Recent wildfires in interior Alaska have left substantial volumes of burned timber, potentially usable for biomass energy. Motivated,in part, by ...
Background. To determine total upper limb function following selective neck dissection over a mean follow-up of 1.6 years. Methods. A retrospective questionnaire study in a tertiary head and neck surgical unit. One hundred forty-eight patients who underwent selective neck dissection for head and neck cancer from January 2000 to December 2005 were invited to participate. The main outcome measure was ipsilateral upper limb dysfunction as measured by the Disability of Arm, Shoulder and Hand (DASH) questionnaire. Results. Sixty-five patients responded to the invitation to join the study from 148 invited. Despite accessory nerve conserving surgery for all the selective neck dissections studied, 23% reported no upper limb dysfunction, 54% reported mild upper limb dysfunction, 15% reported modera...
Ultraconserved elements (UCEs) are sequences that are identical between reference genomes of distantly related species. As they are under negative selection and enriched near or in specific classes...Full Text Available
The transformation and the accommodation of National Power System (SEN) units to a new management system, own to a decentralized economy and having financial support from both native capital and foreign capital, in uncertain proportion at the moment and being in a continuous adjustment determined by the reasons and the motivations first of all political, generated conceptual changes in the so-called modern management theory. The accommodation of this theory to the concrete situation from SEN units imposed the concept of negative selection. It is a concept which represents author's desire to be created as an original contribution to the contemporary management theory. Unlike the selection at the hiring (or positive selection), the negative selection is achieved on personal already employed, in the conditions of activities of a decreased number of personnel and also of a redistribution of personnel on the ...
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
We present results on searches for exotic particles (relativistic magnetic monopoles and WIMPs) and for UHE neutrinos, obtained with the Baikal neutrino telescope NT200.
A specific radiochemical procedure for indium determination in semiconductor-grade silicon, using an inorganic ion exchanger (cerium oxalate) is proposed.
Deltombe T, Gustin T. Selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients: a 2-year longitudinal follow-up of 30 cases. Objective To assess the long-term efficacy of selective tibial neurotomy in the treatment of spastic equinovarus foot in hemiplegic patients. Design Intervention study (before-after trial) with an observational design and 2-year follow-up. Setting Spasticity group in a university hospital. Participants Hemiplegic patients (N=30) with spastic equinovarus foot. Intervention A selective neurotomy was performed at the level of the motor nerve branches of the tibial nerve. Main Outcome Measures Spasticity (Ashworth scale), muscle strength (Medical Research Council scale), passive ankle dorsiflexion, gait parameters (6 min walking test...
This paper proposes a new approach based on missing value pattern discovery for classifying incomplete data. This approach is particularly designed for classification of datasets with a small...Full Text Available
... as the difference between date of birth and date of ... Final model selections were based on the ... approval by the Naval Submarine Medical Research ...
Synthetic polymers and nanomaterials display selective phenotypic effects in cells and in the body that affect signal transduction mechanisms involved in inflammation, differentiation, proliferation,...Full Text Available
... And those who study cognition select problems (eg, tower of Hanoi, missionaries and cannibals, logic theorems) with minimal perceptual and motor ...
Several years ago, the AGARD Structures and Materials Panel selected ... flow separation appears to have occurred during the tests, and the angles of attack ...
NEWTON's first law prohibits the coupling of free tachyons to ordinary matter, if it is interpreted as selection rule interdicting emission without change of the rest-mass of the emitting system.
The tremendous growth of wireless technologies has introduced the potential of continuous service adaptation to the users' needs by giving them the ability to be able to select and access the proper network based on different criteria. Moreover, next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. However, the expansion of Wireless Local Area Networks (WLANs) and Worldwide Interoperability for Microwave Access (WiMAX) networks poses new research era in the decision of the access network selection. In this paper, the existing access network selection schemes are classified into three categories: the network-centric, the user-centric and the collaborative sche...
Jul 7, 2008 ... HOUSTON -- Following a detailed, integrated assessment, NASA selected ... in the center that provides a 360-degree view around the station. ...
The KDP crystal was 10 cm long and cut such that the c-axis was 50.3* to the normal of its input face. We selected for study idler and signal beams ...
BackgroundWhereas there is increasing evidence that loss of expression and/or function of the thyroid hormone receptors (TRs) could result in a selective advantage for tumor development,...Full Text Available
... the area covered by the point-count grid, stopping approximately every 100 m, stepping away from the vehicle, and scanning with binoculars for mountain plovers. Once ... ...
The purpose of this report is to provide management with performance data on key performance indicators selected from the FFTF Early Warning System performance indicators.
... Using a weighted linear regression on randomly selected coincident SSM/I-buoy pairs from each of the climate m codes, it was possible to produce ...
... This is the case for the 82nd Airborne Division ready brigade force (DRB) and the Military Airlift Command (MAC) strategic airlift system operating ...
By using the paired comparison methodology, it was possible to establish evaluative priorities, providing criterion weights which reflected the thoughts and feelings of an advisory committee consisting of experts in the task selection process. For the U.S. Army Infantry School, the weights can be used to stress higher weighted criterion results in the task selection process. By extending the size and diversity of the advisory committee, the use of paired comparison methodology can provide an effective, reliable procedure for (1) constructing evaluative criterion weights for the task selection process and in other areas which have multiple criteria used for evaluative purposes and (2) incorporating into an evaluative design the valuable contributions of various experts and interest groups. (Author/BW)
... spontaneous radiation of amplifiers within a relatively w~de range of ... pulse widths are 20-30ns, while amplified spontaneous radiation pulse ...
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The goal of this investigation is to research possible methodologies into automating the design of, specifically, nuclear power facilities; however, it is relevant to all thermal power systems. The strategy of this research has been to concentrate on individual areas of the thermal design process, investigate procedures performed, develop methodology to emulate that behavior, and prototype it in the form of a computer program. The design process has been generalized as follows: problem definition, design definition, component selection procedure, optimization and engineering analysis, testing and final design with the problem definition defining constraints that will be applied to the selection procedure as well as design definition. The result of this research is a prototype computer program applying an original procedure for the selection of the best set of real components that would be used in constructing a system with ...