bluuebunny/crossref_metadata_2025 huggingface dataset:
2010 Review of Neutron and Non-neutron Nuclear Data
Authors: Holden N. E.
Published: May 2012

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature over the past three years are presented. The status of new chemical elements is examined. Ten elements have had their atomic weight and uncertainty replaced by interval values of upper and lower bounds. Data on revised values for the isotopic composition of the elements are reviewed and new recommended values are presented for germanium. Radioactive half-lives are reviewed and latest values presented which include measurements on nuclides of interest and very long-lived nuclides such as double beta decay, double electron capture, long-lived alpha decay, and long-lived beta decay. The latest information and the status on the evaluation of atomic masses are discussed. Data from new measurements on the very heavy elements (trans-meitnerium elements) are discussed and tabulated. Data on various recent neutron cross-section and resonance integral measurements are also discussed and the latest measurements are tabulated in both cases. The JENDL-4.0 and ENDF/B-VII.1 nuclear data libraries are discussed. A new initiative on the existence and importance of isotopes is presented.
Uncertainties of Responses Calculated with a “Tuned” Library: Geometrical and Algebraic Insights
Authors: Perel R. L.
Published: May 2012

The standard American evaluated nuclear data library ENDF/B-VII was “tuned” based on simple measured critical assemblies. This tuning was not done according to a fully defined mathematical algorithm, such as the adjustment algorithm. In this work, we investigate how tuning affects the uncertainties (covariances) of the cross-section libraries. First, we analyze what happens to cross-section uncertainties as a result of adjustment. The effect of adjustment on the uncertainties is geometrically demonstrated for simple cases. For those parts of the sensitivities of the assembly to be calculated that are parallel to the sensitivities of the assemblies on which adjustment was based, there is significant reduction in the uncertainties. For orthogonal parts, there is no change in the uncertainties. These findings are algebraically proven based on the adjustment algorithm. Then we analyze the differences between tuned libraries and adjusted libraries. We conclude that for tuned libraries, the uncertainties in the direction of sensitivities on which adjustment or tuning were based are improved, similar to the improvement for an adjusted library. However, the displacement of the nominal values of the library parameters to their tuned value, instead of their adjusted value, adds an additional uncertainty. This additional uncertainty is typically small in the direction that was improved by adjustment. The magnitude of the additional uncertainty in perpendicular directions depends on the particular details of the tuning performed.
Reactor Pulse-Repeatability Studies at the Annular Core Research Reactor
Authors: DePriest K. Russell , Trinh Tri Q. , Luker S. Michael
Published: May 2012

The Annular Core Research Reactor (ACRR) at Sandia National Laboratories is a water-moderated pool-type reactor designed for testing many types of objects in the pulse and steady-state mode of operations. Personnel at Sandia began working to improve the repeatability of pulse operations for experimenters in the facility. The ACRR has a unique UO2–BeO fuel that makes the task of producing repeatable pulses difficult with the current operating procedure. The ACRR produces a significant quantity of photoneutrons through the 9Be(γ, n)8Be reaction in the fuel elements. The photoneutrons are the result of the gammas produced during fission and in fission product decay, so their production is very much dependent on the reactor power history and changes throughout the day/week of experiments in the facility. Because the photoneutrons interfere with the delayed-critical measurements required for accurate pulse reactivity prediction, a new operating procedure was created. The photoneutron effects at delayed critical are minimized when using the modified procedure. In addition, the pulse element removal time is standardized for all pulse operations with the modified procedure, and this produces less variation in reactivity removal times.
Investigation of Load Control Errors for Spectrum Fatigue Testing at High Frequencies
Authors: Rusk David T. , Taylor Robert E.
Published: May 2012

Ultra-high cycle fatigue (gigacycle) tests have shown that a true fatigue endurance limit does not exist for most metallic materials used in high cycle applications. These findings have significant implications for rotorcraft dynamic structural components that have traditionally been designed using endurance limit, stress-life methods. Unfortunately, the gigacycle fatigue test results generated to date cannot be easily applied to rotorcraft component design, because the interaction of different crack nucleating mechanisms under variable amplitude loading is not well understood, and must be studied using spectrum fatigue tests carried out to very long lives. To quantify the effect of spectrum load control errors on the rate of fatigue damage accumulation for a standard servo-hydraulic fatigue test machine, a damage ratio parameter for crack initiation is calculated using the high cycle fatigue portion of the Coffin-Manson strain-life curve with rainflow cycle counting. The fatigue damage parameter allows the level of controller error to be assessed as a function of test frequency, peak load levels, and test spectrum complexity. Also, different command feedback compensation schemes are tested to determine the range of control error that can be expected for a given set of test parameters. A sensitivity study was performed on the command signal response errors as a function of changes in the slope of the mean damage curve beyond 106 cycles. The test results demonstrate that rotorcraft spectrum fatigue tests can be performed at frequencies up to 150 Hz with a level of nominal damage accumulation error less that 1 % under most conditions. When electrical measurement system error is accounted for, the damage accumulation error is less than 2 % under most conditions. The results also show that it is important to consider the shape of the stress-life curves in the gigacycle fatigue range when performing spectrum tests out to long fatigue lives.
The Fast Neutron Fluence and the Activation Detector Activity Calculations Using the Effective Source Method and the Adjoint Function
Authors: Hep J. , Konečná A. , Krýsl V. , Smutný V.
Published: May 2012

This paper describes the application of effective source in forward calculations and the adjoint method to the solution of fast neutron fluence and activation detector activities in the reactor pressure vessel (RPV) and RPV cavity of a VVER-440 reactor. Its objective is the demonstration of both methods on a practical task. The effective source method applies the Boltzmann transport operator to time integrated source data in order to obtain neutron fluence and detector activities. By weighting the source data by time dependent decay of the detector activity, the result of the calculation is the detector activity. Alternatively, if the weighting is uniform with respect to time, the result is the fluence. The approach works because of the inherent linearity of radiation transport in non-multiplying time-invariant media. Integrated in this way, the source data are referred to as the effective source. The effective source in the forward calculations method thereby enables the analyst to replace numerous intensive transport calculations with a single transport calculation in which the time dependence and magnitude of the source are correctly represented. In this work, the effective source method has been expanded slightly in the following way: neutron source data were performed with fewgroup method calculation using the active core calculation code moby-dick. The follow-up neutron transport calculation was performed using the neutron transport code tort to perform multigroup calculations. For comparison, an alternative method of calculation has been used based upon adjoint functions of the Boltzmann transport equation. Calculation of the three-dimensional (3-D) adjoint function for each required computational outcome has been obtained using the deterministic code tort and the cross section library BGL440. Adjoint functions appropriate to the required fast neutron flux density and neutron reaction rates have been calculated for several significant points within the RPV and RPV cavity of the VVER-440 reactor. Both of calculation methods are briefly described and the results are compared.
Dosimetry Assessments for the Reactor Pressure Vessel and Core Barrel in UK Pressurized Water Reactor (PWR) Plant
Authors: Thornton D. A. , Allen D. A. , Huggon A. P. , Picton D. J. , Robinson A. T. , Steadman R. J. , Serén T. , Lipponen M. , Kekki T.
Published: May 2012

Specimens for the Sizewell B reactor pressure vessel (RPV) in-service steels surveillance program are irradiated inside eight capsules located within the reactor pressure vessel and loaded prior to commissioning. The periodic removal of these capsules and testing of their contents provides material properties data at intervals during the lifetime of the plant. Neutron activation measurements and radiation transport calculations play an essential role in assessing the neutron exposure of the specimens and RPV. Following the most recent withdrawal, seven capsules have now been removed covering nine cycles of reactor operation. This paper summarizes the dosimetry results of the Sizewell B surveillance program obtained to date. In addition to an overview of the calculational methodology it includes a review of the measurements. Finally, it describes an extension of the methodology to provide dosimetry recommendations for the core barrel and briefly discusses the results that were obtained.
VENUS-F: A First Fast Lead Critical Core for Benchmarking
Authors: Kochetkov A. , Wagemans J. , Vittiglio G.
Published: May 2012

The zero-power thermal neutron water-moderated facility VENUS at SCK•CEN has been extensively used for benchmarking in the past. In accordance with GEN-IV design tasks (fast reactor systems and accelerator driven systems), the VENUS facility was modified in 2007–2010 into the fast neutron facility VENUS-F with solid core components. This paper introduces the projects GUINEVERE and FREYA, which are being conducted at the VENUS-F facility, and it presents the measurement results obtained at the first critical core. Throughout the projects other fast lead benchmarks also will be investigated. The measurement results of the different configurations can all be used as fast neutron benchmarks.
Comparison of Regulatory Guide 1.99 Fluence Attenuation Methods
Authors: Jones Eric N.
Published: May 2012

U.S. Regulatory Guide 1.99 Revision 2 (U.S. Nuclear Regulatory Commission, 1988, “Radiation Embrittlement of Reactor Vessel Materials,” Regulatory Guide 1.99, Revision 2, Washington, D.C.) provides for the use of two substantially different methods for determining through-wall fluence in nuclear reactor pressure vessels. One method is a generic attenuation curve based on a simplistic exponential decay equation. Partly due to the simplicity of its application, the generic attenuation method is predominantly used for licensing calculations. However, it has a limitation in that at increasing distances away from the core beltline, it becomes increasingly less accurate because it cannot account for neutron streaming effects in the cavity region surrounding the pressure vessel. The other attenuation method is based on a displacement per atom (dpa) calculation specific to the reactor vessel structure. The dpa method provides a more accurate representation of fluence attenuation through the reactor pressure vessel (RPV) wall at all elevations of the pressure vessel because it does account for neutron streaming in the cavity region. A requirement for using the dpa method, however, is an accurate flux solution through the RPV wall. This requirement has limited the use of traditional transport methods, such as discrete ordinates, that are limited by their treatment of cavity regions (i.e., air) outside the pressure vessel wall. TransWare Enterprises, under the sponsorship of EPRI and BWRVIP, has developed an advanced three-dimensional transport methodology capable of producing fully converged flux solutions throughout the entire reactor system, including in the cavity region and primary shield structures. This methodology provides an accurate and reliable determination of through-wall fluence in boiling water reactor (BWR) and pressurized water reactor (PWR) pressure vessels, thus allowing the dpa method to be implemented with high reliability. Using this advanced 3-D methodology, this paper presents comparisons of the generic and dpa attenuation methods at critical locations in both BWR and PWR pressure vessel walls.
Dosimetry Analyses of the Ringhals 3 and 4 Reactor Pressure Vessels
Authors: Kulesza Joel A. , Fero Arnold H. , Roudén Jenny , Green Eva-Lena
Published: May 2012

A comprehensive series of neutron dosimetry measurements consisting of surveillance capsules, reactor pressure vessel cladding samples, and ex-vessel neutron dosimetry has been analyzed and compared to the results of three-dimensional, cycle-specific neutron transport calculations for the Ringhals Unit 3 and Unit 4 reactors in Sweden. The comparisons show excellent agreement between calculations and measurements. The measurements also demonstrate that it is possible to perform retrospective dosimetry measurements using the 93Nb (n,n′) 93mNb reaction on samples of 18-8 austenitic stainless steel with only trace amounts of elemental niobium.
CALMOS: Innovative Device for the Measurement of Nuclear Heating in Material Testing Reactors
Authors: Carcreff H.
Published: May 2012

An R&D program has been carried out since 2002 in order to improve gamma heating measurements in the 70 MWth OSIRIS Material Testing Reactor operated by CEA’s Nuclear Energy Division at the Saclay research center. Throughout this program an innovative calorimetric probe associated to a specific handling system has been designed in order to make measurements both along the fissile height and on the upper part of the core, where nuclear heating rates still remain high. Two mock-ups of the probe were manufactured and tested in 2005 and 2009 in ex-core area of OSIRIS reactor for the process validation, while a displacement system has been especially designed to move the probe axially. A final probe has been designed thanks to modeling results and to preliminary measurements obtained with mock-ups irradiated to a heating level of 2 W/g, This paper gives an overview of the development, describes the calorimetric probe, and expected advantages such as the possibility to use complementary methods to get the nuclear heating measurement. Results obtained with mock-ups irradiated in ex-core area of the reactor are presented and discussed.
Sensitivity of Adjustment to Parameter Correlations and to Response-Parameter Correlations
Authors: Wagschal J. J.
Published: May 2012

The adjusted parameters and response, and their respective posterior uncertainties and correlations, are presented explicitly as functions of all relevant prior correlations for the two parameters, one response case. The dependence of these adjusted entities on the various prior correlations is analyzed and portrayed graphically for various valid correlation combinations on a simple criticality problem.
Exposure Conditions of Reactor Internals of Rovno VVER-440 Nuclear Power Plant Units 1 and 2
Authors: Grytsenko O. V. , Pugach S. M. , Diemokhin V. L. , Bukanov V. N. , Marek M. , Vandlik S.
Published: May 2012

Results of determination of irradiation conditions for vessel internals of VVER-440 reactor No. 1 and 2 at Rovno Nuclear Power Plant, obtained by specialists at Institute for Nuclear Research Kyiv, Ukraine, and Nuclear Research Institute Rez, Czech Republic, are presented. To calculate neutron transport, detailed calculation models of these reactors were prepared. Distribution of neutron flux functionals on the surface of reactor VVER-440 baffle and core barrel for different core loads was studied. Agreement between results obtained by specialists at Institute for Nuclear Research and at Nuclear Research Institute is shown.
Analysis of Dosimetry from the H. B. Robinson Unit 2 Pressure Vessel Benchmark Using raptor-m3g and ALPAN
Authors: Fischer Greg A.
Published: May 2012

The dosimetry from the H. B. Robinson Unit 2 Pressure Vessel Benchmark is analyzed with a suite of Westinghouse-developed codes and data libraries. The radiation transport from the reactor core to the surveillance capsule and ex-vessel locations is performed by raptor-m3g, a parallel deterministic radiation transport code that calculates high-resolution neutron flux information in three dimensions. The cross-section library used in this analysis is the ALPAN library, an Evaluated Nuclear Data File (ENDF)/B-VII.0-based library designed for reactor dosimetry and fluence analysis applications. Dosimetry is evaluated with the industry-standard snlrml reactor dosimetry cross-section data library.
Development of INSPCT-S for Inspection of Spent Fuel Pool
Authors: Walters William , Haghighat Alireza , Sitaraman Shivakumar , Ham Young
Published: May 2012

In this paper, we discuss an accurate and fast software tool (INSPCT-S, Inspection of Nuclear Spent fuel-Pool Calculation Tool, version Spreadsheet) developed for calculation of the response of fission chambers placed in a spent fuel pool, such as Atucha-I. INSPCT-S is developed for identification of suspicious regions of the pool that may have missing or substitute assemblies. INSPCT-S uses a hybrid algorithm based on the adjoint function methodology. The neutron source is comprised of spontaneous fission, (α, n) interactions, and subcritical multiplication. The former is evaluated using the ORIGEN-ARP code, and the latter is obtained with the fission matrix (FM) formulation. The FM coefficients are determined using the MCNP Monte Carlo code, and the importance function is determined using the PENTRAN 3-D parallel Sn code. Three databases for the neutron source, FM elements, and adjoint flux are prepared as functions of different parameters including burnup, cooling time, enrichment, and pool lattice size. INSPCT-S uses the aforementioned databases and systems of equations to calculate detector responses, which are subsequently compared with normalized experimental data.
Fitting Method for Spectrum Deduction in High-Energy Neutron Field Induced by GeV-Protons Using Experimental Reaction-Rate Data
Authors: Kasugai Y. , Matsuda N. , Sakamoto Y. , Nakashima H. , Yashima H. , Matsumura H. , Iwase H. , Hirayama H. , Mokhov N. , Leveling A. , Boehnlein D. , Vaziri K. , Lauten G. , Oishi K. , Nakamura T.
Published: May 2012

The Japanese and American Study of Muon Interaction and Neutron detection (JASMIN) collaboration, has been conducting shielding experiments using the Fermilab anti-proton target station (Pbar) shielding assembly. A multi-foil technique was used to measure the high energy neutron spectra, in the range of 1 to 100 MeV, for the target station shielding configuration. The neutron spectra were de-convoluted using a new fitting method. This method is based on the assumption that a neutron spectrum can be expressed as a simple sum of two exponentials. The validity of the fitting method was confirmed by comparison with the results obtained using SAND-II computer code and theoretical calculations. Finally, it was found that there are simple correlations between reaction rates and the adjustable parameters in the fitting function.
Photon Spectrum behind Biological Shielding of the LVR-15 Research Reactor
Authors: Klupák V. , Viererbl L. , Lahodová Z. , Marek M. , Vinš M.
Published: May 2012

The LVR-15 reactor is a light water research reactor situated at the Research Centre Řež, near Prague. It operates as a multipurpose facility with a maximum thermal power of 10 MW. The reactor core usually contains from 28 to 32 fuel assemblies with a total mass of 235U of about 5 kg. Emitted radiation from the fuel caused by fission is shielded by moderating water, a steel reactor vessel, and heavy concrete. This paper deals with measurement and analysis of the gamma spectrum near the outer surface of the concrete wall, behind biological shielding, mainly in the 3- to 10-MeV energy range. A portable HPGe detector with a portable multichannel analyzer was used to measure gamma spectra. The origin of energy lines in gamma detector spectra was identified.
Apparatus for Use in Evaluating Protection from Low Pressure Hot Water Jets
Authors: Jalbani S. H. , Ackerman M. Y. , Crown E. M. , van Keulen M. , Song G.
Published: May 2012

Use of hot water has become extensive, especially in bitumen extraction from oil sands and in the production of heavy oil. The hot water is often under pressure and is 80–90°C, which is well above temperatures that result in immediate, potentially severe burn injuries. The ASTM F2701-08 apparatus consists of a funnel through which hot liquid is hand-poured to produce a 10 s exposure. Two 40 mm diameter copper calorimeters, mounted in an insulating sheet are positioned beneath the funnel outlet and are intended to measure the energy transfer through the fabric from the hot liquid. For this research, changes were made to the apparatus and procedures to more closely simulate low pressure hot water streams found in the oil industry and to improve reproducibility. The funnel producing the liquid splash was replaced with a small pipe directly fed by a circulating hot water bath via a small pump, through a hose and valve system, allowing for consistent application of a given quantity of water at a consistent temperature and flow rate. Water temperature, flow rate, and pressure can be altered as desired. A series of fabrics varying systematically on several parameters were tested with the modified equipment. Resulting heat transfer data suggest the system differentiates well among both semi-permeable and impermeable fabrics. Specifications for hot water protection are proposed.
Path Forward for Dosimetry Cross Sections
Authors: Griffin P. J. , Peters C. D.
Published: May 2012

In the 1980’s the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of “due consideration” of experimental data in the evaluation.
A New Formulation of the Unified Monte Carlo Approach (UMC-B) and Cross-Section Evaluation for the Dosimetry Reaction 55Mn(n,γ)56Mn
Authors: Capote Roberto , Smith Donald L. , Trkov Andrej , Meghzifene Mehdi
Published: May 2012

Two relatively new approaches to neutron cross section data evaluation are described. They are known collectively as Unified Monte Carlo (versions UMC-G and UMC-B). Comparisons are made between these two methods, as well as with the well-known generalized least-squares (GLSQ) technique, through the use of simple, hypothetical (toy) examples. These new Monte Carlo methods are based on stochastic sampling of probability functions that are constructed with the use of theoretical and experimental data by applying the principle of maximum entropy. No further assumptions are involved in either UMC-G or UMC-B. However, the GLSQ procedure requires the linearization of non-linear terms, such as those that occur when cross section ratio data are included in an evaluation. It is shown that these two stochastic techniques yield results that agree well with each other, and with the GLSQ method, when linear data are involved, or when the perturbations due to data discrepancies and nonlinearity effects are small. Otherwise, there can be noticeable differences. The present investigation also demonstrates, as observed in earlier work, that the least-squares approach breaks down when these conditions are not satisfied. This paper also presents an actual evaluation of the 55Mn(n,γ)56Mn neutron dosimetry reaction cross section in the energy range from 100 keV to 20 MeV, which was performed using both GLSQ and UMC-G approaches.
Jules Horowitz Reactor, a New Irradiation Facility: Improving Dosimetry for the Future of Nuclear Experimentation
Authors: Grégoire Gilles , Beretz Daniel , Destouches Christophe
Published: May 2012

The Jules Horowitz Reactor (JHR) is an experimental reactor under construction at the French Nuclear Energy and Alternative Energies Commission (CEA) facility at Cadarache. It will achieve its first criticality by the end of 2014. Experiments that will be conducted at JHR will deal with fuel, cladding, and material behavior. The JHR will also produce medical radio-isotopes and doped silicon for the electronic industry. As a new irradiation facility, its instrumentation will benefit from recent improvements. Nuclear instrumentation will include reactor dosimetry, as it is a reference technique to determine neutron fluence in experimental devices or characterize irradiation locations. Reactor dosimetry has been improved with the progress of simulation tools and nuclear data, but at the same time the customer needs have increased: Experimental results must have reduced and assessed uncertainties. This is now a necessary condition to perform an experimental irradiation in a test reactor. Items improved, in the framework of a general upgrading of the dosimetry process based on uncertainty minimization, will include dosimeter, nuclear data, and modelling scheme.
Korean Standard Nuclear Plant Ex-Vessel Neutron Dosimetry Program Ulchin 4
Authors: Duo J. I. , Chen J. , Kulesza J. A. , Fero A. H. , Yoo C. S. , Kim B. C.
Published: May 2012

A comprehensive ex-vessel neutron dosimetry (EVND) surveillance program has been deployed in 16 pressurized water reactors (PWR) in South Korea and EVND dosimetry sets have already been installed and analyzed in Westinghouse reactor designs. In this paper, the unique features of the design, training, and installation in the Korean standard nuclear plant (KSNP) Ulchin Unit 4 are presented. Ulchin Unit 4 Cycle 9 represents the first dosimetry analyzed from the EVND design deployed in KSNP plants: Yonggwang Units 3 through 6 and Ulchin Units 3 through 6. KSNP’s cavity configuration precludes a conventional installation from the cavity floor. The solution, requiring the installation crew to access the cavity at an elevation of the active core, places a premium on rapid installation due to high area dose rates. Numerous geometrical features warranted the use of a detailed design in true 3D mechanical design software to control interferences. A full-size training mockup maximized the crew ability to correctly install the instrument in minimum time. The analysis of the first dosimetry set shows good agreements between measurement and calculation within the associated uncertainties. A complete EVND system has been successfully designed, installed, and analyzed for a KNSP plant. Current and future EVND analyses will continue supporting the successful operation of PWR units in South Korea.
Seismic Racking Test Evaluation of Silicone Used in a Four-Sided Structural Sealant Glazed Curtain Wall System
Authors: Broker K. A. , Fisher S. , Memari A. M.
Published: May 2012

This paper presents the results of a study in which four-sided structural sealant glazing (SSG) insulating glass curtain wall units were subjected to cyclic racking test methods in accordance with AAMA 501.6 testing protocols. The test configuration included three side-by-side primary units and a corner unit. High-resolution cameras were utilized to capture instantaneous images during the racking test so that the displacement within the sealant joint could be captured and isolated from the displacement of the entire glazed unit. Drift capacity of the system in terms of glass attachment and sealant performance is reported in detail for different levels of racking displacements and boundary conditions. The overall behavior of the system is characterized, and specifically the sealant performance at a corner condition during racking drift is discussed. Additionally, expected strains in the sealant were calculated using a linear-elastic finite element model and were then compared with the strains the actual structural sealant joint underwent during system testing. Silicone sealant damage was evaluated using visual observation before and after cyclic racking. The paper discusses proposed acceptable sealant stress levels for seismic design and the durability of silicone used in the SSG system as compared to dry-glazed systems based on glass performance.
Case Studies of Adhesive and Rigid Insulation Board Failures due to Moisture in Low Sloped Roofing Assemblies
Authors: Slick David Straup , Piteo Nicholas A. , Rutila Dean A.
Published: May 2012

Foamed adhesives are used to join roofing assembly components to the roof substrate and to each other. A variety of performance problems with foamed adhesives as installed in roofing assemblies have led to assembly failures. We previously reported, in detail, four specific failure mechanisms caused by poor adhesive installation that we have observed, and we briefly note these failure mechanisms in order to maintain continuity as we expand on our earlier work. The focus of this paper is to report on other factors that also lead to adhesive and rigid insulation board performance problems, specifically, moisture contained within the roofing assembly and substrate, which can result in the failure of the roofing assembly. Similar substrate moisture issues occur in flooring assemblies; however, whereas the flooring industry continues to address moisture-related issues that lead to adhesive performance problems, the roofing and roofing adhesive industries have been less proactive regarding use, installation, and testing for assemblies with potential moisture-related issues. We present several case studies that illustrate excessive moisture in roofing assemblies or substrates as an issue that contributed to the adhesive failure of the roofing assembly. We also discuss the lessons to be learned from not addressing these issues at the onset of a project.
A Model to Estimate Separator Forces during Ball Speed Variations
Authors: Leveille Alan , Frantz Peter , Rosene Garry
Published: May 2012

When the combined loads on ball bearings include forces in the radial or moment directions, the balls will not orbit the bearing at one common speed. This ball speed variation (BSV) might result in additional bearing friction forces if the variation in speed is large enough to allow the balls to spread out from their normal spacing by an amount that exceeds the cage pocket clearances. In this paper we present a model used to estimate the cage forces and friction torques caused by BSV and compare the model predictions with measured friction torque test data. The model first analyzes the forces on a single ball by determining the distance over which a ball must slip during a single orbit of the bearing center. The ball to race force is determined by equating the energy lost during this slip with the energy input through traction at the inner race interface. The component of the ball to cage force normal to the ball–pocket interface is then determined by balancing this force with the ball to race force. The cage to land force is similarly determined by balancing the collective forces at all the ball to race and ball to cage interfaces. Finally, the BSV drag torque is written as the sum of contributions from these three drag sources. In order to validate the model, test data were obtained using single 204 size bearings operating under applied thrust and radial loading. The bearing drag torque was found to depend on the degree of misalignment and cage pocket clearance, as predicted by the model.
Removal of Heavy Metals (Cu, Pb, and Zn) from Contaminated Sediment Using a Flotation Technique
Authors: Palakkeel veetil Dileep , Mercier Guy , Blais Jean-Francois
Published: May 2012

This paper investigates the effectiveness of froth flotation to remove copper and other heavy metals from dredged anoxic sediments (<250 μm) using a lab scale flotation cell with a selected anionic collector. A sediment fraction selected for flotation tests was potentially contaminated with a copper concentration of about 1763 mg/kg. The sequential extraction study of sediments showed that copper was mainly incorporated, between 70%–85% in the sulfide-organic fraction. The mineralogical analysis of sediment particle by scanning electron microscopy identified that chalcopyrite was the predominant copper sulfide form in the sediments. Flotation tests under controlled, predetermined experimental conditions showed selective flotation removal of copper (70.4%) among other metals with less mass recovery (froth mass).
Glass Unit Corner Loading—Key Parameter in Durability
Authors: Hagl Anneliese , Dieterich Oliver
Published: May 2012

Bent glass has garnered increased interest on the part of architects for the realization of curved glass façades. As one method of bending of glass façade units, cold bending is an economically efficient procedure for manufacturing; however, it introduces permanent stresses in the glazing structure, especially in the corner zones of the glass units for warped designs. In a similar manner, high stresses in the corner zones are also generated in general by constant surface loads acting on the panes of the glass unit, which can be explained by thin plate theory. Thus it can be expected that these unsteady loads, e.g., evoked by wind and/or snow loads, unfavorably interfere with the permanent stresses in the adhesives of both the structural glazing sealant and the insulating glass sealant from a durability point of view. The existence of these corner loads is not adequately accounted for by the ETAG 002 guideline for structural glazing applications, which postulates a trapezoidal load distribution in the bonding with diminishing stresses in the corner zones. This paper presents numerical results of a parametric study of pressure-loaded glass units, with a focus on corner loads and stresses. The results show that the stress levels in the corner zones might be significantly higher than the design stress values used for sizing the bonding.
Bearing Thermal Conductance Measurement Test Method and Experimental Design
Authors: Takeuchi Yoshimi R. , Davis Sean E. , Eby Matthew A. , Fuller Jerry K. , Taylor Donald L. , Rosado Michael J.
Published: May 2012

Bearings are used in a number of spacecraft applications, ranging from minimal motion devices, such as pointing mechanisms, to high-speed components, such as control moment gyroscopes and reaction and momentum wheels. Terrestrial applications include pumps, axles, and tooling. Heat-transfer modes for rotational systems in a vacuum environment differ from their terrestrial counterpart. In space, with the absence of air, heat transfer consists of radiation from the rotating system and conductance through the bearings themselves. Depending on the application, conductance could dominate the effects on bearing temperatures and thermal gradients. Accurate thermal predictions are important because they can drive life and performance requirements. To accurately predict bearing temperatures, basic bearing thermal conductance data was needed. However, bearing thermal conductance tends to be the most significant unknown in a rotational system in the space environment. To address this shortcoming, this paper explores a new vacuum test rig designed to measure bearing conductance under simulated operational conditions. Experimental variables include control of the bearing rotational speed, applied axial load, and average bearing temperature and temperature gradient via an applied heat source/heat sink mechanism. All tests are conducted in vacuum. The experimental variables studied herein allowed parametric studies to be conducted under controlled thermal and mechanical conditions, permitting the exploration of the influences of those operational variables on bearing thermal conductance. This paper will describe the test method, the use of uncertainty analysis to design the experiment, and a verification study.
Comparison between Hybrid III Headforms by Linear and Angular Dynamic Impact Response Characteristics
Authors: Kendall Marshall , Hoshizaki Thomas Blaine
Published: May 2012

The development of surrogate headforms with similar dimensions and weight to that of a human head has allowed researchers to collect dynamic impact response data for impact reconstructions and injury assessment. These headforms are relied upon to deliver accurate and repeatable dynamic impact response data for setting helmet certification standards as well as head injury reconstruction. With recent research demonstrating the importance of measuring three dimensional dynamic impact response characteristics, the Hybrid III headform is a potentially a good candidate for use in standards testing and impact reconstructions. Currently, this headform is validated with a single 37.6-cm drop to the front region of the headform with an acceptance window of 50 g. Therefore, the purpose of this study was to compare the dynamic impact response of two Hybrid III headforms and verify repeatability, compare dynamic impact response, and determine how closely the two headforms correlate across different impact conditions. Two Hybrid III headforms were dropped from nine heights at two impact locations (front and side). Results of this study show that the two headforms are highly correlated across drop heights. Significant differences in terms of dynamic impact response were found between the two headforms across impact conditions. This study showed that two Hybrid III headforms produce similar mean peak linear acceleration for front centric impacts, however, differ significantly for mean peak angular response.
Alpine Skiing, Telemarking, Snowboarding, and Skiboarding Injuries Related to Gender and Ability
Authors: Ekeland Arne , Rødven Andreas
Published: May 2012

A central ski-patrol-based registration of skiing and boarding injuries was performed by the Norwegian Ski Lift Association during the winter seasons 2008/2009 and 2009/2010 as part of an ongoing study since 1996. Totals of 8547 injured skiers/boarders and 6.621 × 106 s of skier/boarder days were recorded during the two seasons, giving an injury rate of 1.29 injured per 1000 skier/boarder days. Most of the injuries occurred during alpine skiing (67 %) and snowboarding (29 %), compared to telemark skiing (2 %), and skiboarding (2 %). Wrist injuries were common among injured snowboarders (22 %) compared to 1–6 % for the others (P < 0.001). The knee was the main injury location in alpine skiers (24 %) compared to only 8 % among snowboarders (P < 0.001). The prevalence of knee injuries for females (31 %) was twice as high as for males (15 %) (P < 0.001), whereas shoulder injuries was more than twice as high for males (18 %) as for females (7 %) (P < 0.001). These gender differences were observed in all four skiing/boarding ability groups. Snowboarders suffered more fractures (29 %) than the others, but fracture of the lower leg was uncommon among snowboarders (0.5 %) compared to alpine skiers (7 %) (P < 0.001). Lower leg fractures accounted for 4 % of the injured alpine skiers 20 years and older, and 5 % for adolescents aged 13–19 years compared to 14 % for children 12 years and younger (P < 0.001). In contrast, the prevalence of dislocations and injuries needing ambulance transport increased with increasing age. Twenty-two percent of the skiers/boarders were injured in terrain parks. They had a higher ability, but suffered more fractures and back injuries than those injured at other locations (P < 0.001). Injured experts suffered more injuries in terrain parks and during collisions, and needed more ambulance transport and admission to physicians and hospitals than injured beginners (P < 0.002). The use of protective helmets among injured skiers/boarders has increased from 11 % to 70 % in the period 1996–2010, but the prevalence of head injuries has only dropped from 19 % to 16 % in the same period (P < 0.001). In conclusion, injured alpine skiers were most prone to knee injuries, and snowboarders to wrist injuries. The prevalence of knee injuries among females was twice that of males, whereas the reverse was observed for shoulder injuries. This gender difference was observed in all four ability groups. Injured experts suffered more serious injuries than injured beginners.
Improvement in Efficiency of Ultrasonic Tests for the Macroscopic Inclusions Evaluation
Authors: Aoyama Yosuke , Takasu Ichiro , Unigame Yasukazu
Published: May 2012

Rolling-contact-fatigue life is a key characteristic of bearings. Reliable bearings are expected to have long L10 life as a bearing performance index, as well as long commercial life without unexpected premature failure on any pieces of bearings in use. It has long been known that cleanliness is an important material factor to determine the fatigue life. The aforementioned early failure could be caused by macroscopic inclusions, which have small density of presence in recent clean steel and, thus, detection for those inclusions requires evaluation on a large volume of steel. Although higher-frequency ultrasonic tests have advantages for non-metallic inclusion detections, relatively low frequency of 10- to 20-MHz ultrasonic tests are useful for both evaluation efficiency of large volume and for detection performance of macroscopic inclusions. The authors apply a focused-beam-type 15-MHz ultrasonic test to detect 100-μm or larger macroscopic inclusions, where the efficient evaluation is needed because of the assessment for a large volume of steel. In this paper, the basic characteristics of several procedures of ultrasonic tests will be discussed from the viewpoint of the evaluation efficiency for macroscopic inclusions.
Characterization of Carbon Black Particles Mixing in Polymeric Matrix by Direct Methods
Authors: Jiang Zhao-Hui , Jin Jian , Xiao Chang-Fa , Li Xin , Kong Ling-Xi
Published: May 2012

Single-screw extruders together with a painstakingly self-made dynamic mixer were applied to mix carbon black (CB) in polymeric matrix. Moreover, the master batch dilution technique was also used. The mixing state of CB was investigated by direct methods including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical microscopy (OM). The image analysis software, Image J, was first introduced to analyze the mixing state of CB. By virtue of Image J, the average size, surface density, and area distribution of particles were automatically created. On the basis of TEM results, quantitative evaluation parameters such as Morisita’s index (I), skewness (β), and the Lacey index (M) were employed. The results reveal that CB was well dispersed and uniformly distributed in films. Besides, the area distribution abides by a lognormal equation fitted by origin. In SEM analysis, the area distribution conforms to exponent decay strictly as well as that in OM results. Furthermore, the dispersion index (D) was used to characterize the mixing state of CB. The results imply that CB tends to aggregate with increasing CB loading. Combining the methods mentioned above is favorable to quantitatively characterize the mixing state of CB, in that they can become references between one another.
In-Plane Testing Behavior of Adhesive-Bonded Steel Sheets: Influence of Sheet Surface Roughness, Adhesive Thickness, and Bonding Width
Authors: Kant Ravi , Narayanan R. Ganesh
Published: May 2012

There are various parameters such as bonding width, bond and adhesive thickness, blank surface roughness, adherend thickness, bond length, the geometry of the joint, surface treatment, curing and working temperature, bonding pressure, curing conditions, type of loading, etc. that affect the forming of adhesive bonded blanks in a synergistic manner. The main aim of the present work is to investigate the influence of bonding width, adhesive thickness, and blank surface roughness on the tensile behavior of adhesive bonded blanks. Interstitial free steel grade sheet is used as a base material and the two part epoxy adhesive is used for bonding the base materials. It is found that the engineering stress attained in forming the bonded blank for the same amount of strain is greater if the surface roughness is greater. The extension of the bonded blank at the break point is less for higher surface roughness base materials. With an increase in the adhesive thickness, the engineering stress decreased for a particular strain and there was no effect due to adhesive thickness on the elongation at the break point of the bonded blank. The engineering stress required decreases with the bonding width and the extension at the breaking point of the bonded blank is greater in the case of the bonded blank with a higher bonding width. A sudden fall in engineering stress has occurred in the case of adhesive bonded blanks with higher (2.4 mm) and medium adhesive thickness (1.3 mm), base material surface roughness, and bonding width, while this is not observed in 0.5 mm bonding thickness. The different stages of the forming of adhesive bonded blanks are proposed. Initially, adhesive failure occurs and then base material failure occurs depending on its ductility. Both cohesive failure and interface (adhesive) failure is seen during the forming of adhesive bonded blanks in this work.