bluuebunny/crossref_metadata_2025 huggingface dataset:
One Validation Case of the CFD Software Fluent: Part of the Development Effort of a New Reactor Analysis Tool
Authors: Wieselquist William A.
Published: March 2009

To model Generation IV reactor systems in detail, INEEL is currently developing a new thermal hydraulic analysis tool coupling RELAP5-3D / ATHENA© and the computational fluid dynamics (CFD) software, Fluent. One of the first steps in this endeavor is extensive validation and verification (V&V) of Fluent for various situations of interest, such as the abrupt expansion of a gas entering a gas-cooled reactor core. Fluent results were compared to validation data provided by Baughn, et al. on turbulent air flow through an axisymmetric pipe expansion with constant wall heat flux [1] and uniform wall temperature [2]. Fluent peak Nusselt numbers varied 25% from validation data—well outside experimental uncertainties of 5%. However, non-peak Nusselt numbers varied only 10% from validation data and fully-developed Nusselt numbers were in good agreement with widely-accepted empirical relations such as the Dittus-Boelter Correlation.
IEC-Based Neutron Generator for Security Inspection System
Authors: Wu Linchun , Miley George H.
Published: March 2009

Large nuclear reactors are widely employed for electricity power generation, but small nuclear radiation sources can also be used for a variety of industrial/government applications. In this paper we will discuss the use of a small neutron source based on Inertial Electrostatic Confinement (IEC) of accelerated deuterium ions. There is an urgent need of highly effective detection systems for explosives, especially in airports. While current airport inspection systems are strongly based on X-ray technique, neutron activation including Thermal Neutron Analysis (TNA) and Fast Neutron Analysis (FNA) is powerful in detecting certain types of explosives in luggage and in cargoes. Basic elements present in the explosives can be measured through the (n, n’γ) reaction initiated by fast neutrons. Combined with a time-of-flight technique, a complete imaging of key elements, hence of the explosive materials, is obtained. Among the various neutron source generators, the IEC is an ideal candidate to meet the neutron activation analysis requirements. Compared with other accelerators and radioisotopes such as 252Cf, the IEC is simpler, can be switched on or off, and can reliably produce neutrons with minimum maintenance. Theoretical and experimental studies of a spherical IEC have been conducted at the University of Illinois. In a spherical IEC device, 2.54-MeV neutrons of ∼108 n/s via DD reactions over recent years or 14-MeV neutrons of ∼2×1010 n/s via DT reactions can be obtained using an ion gun injection technique. The possibility of the cylindrical IEC in pulsed operation mode combining with pulsed FNA method would also be discussed. In this paper we examine the possibility of using an alternative cylindrical IEC configuration. Such a device was studied earlier at the University of Illinois and it provides a very convenient geometry for security inspection. However, to calculate the neutron yield precisely with this configuration, an understanding of the potential wall trapping and acceleration of ions is needed. The theory engaged is an extension of original analytic study by R.L. Hirsh on the potential well structure in a spherical IEC device, i.e. roughly a “line” source of neutrons from a cylindrical IEC is a “point” source from the spherical geometry. Thus our present study focuses on the cylindrical IEC for its convenient application in an FNA detecting system. The conceptual design and physics of ion trapping and re-circulation in a cylindrical IEC intended for neutron-based inspection system will be presented.
Welding Qualification Sharing
Authors: Newton Bruce
Published: March 2009

ASME Section IX, “Welding Qualifications”, requires that each organization qualify its own welders and welding procedures. Qualification responsibility cannot be subcontracted, and qualifications administered by one organization cannot be transferred to another organization. This requirement has become the subject of close scrutiny as the demand for efficiency, particularly among nuclear plant owners, has increased. Two recent Code Cases change procedure and performance qualification requirements for the better. The first, N-573i, enables nuclear plant owners to share welding procedure qualifications. The second, N-600ii, enables nuclear plant owners to share welder performance qualifications. Several owners have reduced costs using N-573. N-600, because it is relatively new, has not yet been implemented. Its potential for cost savings, though, is equivalent to that afforded by N-573. This paper discusses ASME Section IX’s procedure and performance qualification philosophy, assesses that philosophy in light of today’s welding environment, and discusses implementation of Code Cases N-573 and N-600.
Inspection Guideline of BWR Core Internals in Japan
Authors: Yamamoto Akio , Iizuka Naoto , Yoshinaga Takeshi , Fujimori Haruo , Motora Yuuichi
Published: March 2009

There are crack experiences of core internal components worldwide. So Thermal and Nuclear Power Engineering Society in Japan organized the committee to prepare the appropriate inspection and evaluation guidelines for core internal components at February, 2000. This committee consists of scholars and representatives from utilities and vendors in Japan. At this committee, guidelines for rational inspection and the evaluation method for structural integrity of each core internal components have been developed. For BWR, inspection guidelines for main core internal components like shroud support, core shroud, top guide, core plate, jet pump etc. were prepared at March 2002. Basic concept of guidelines and inspection guideline of shroud support as example will be explained here.
Next Generation CANDU: Conceptual Design for a Short Construction Schedule
Authors: Hopwood Jerry M. , Love Ian J. W. , Elgohary Medhat , Fairclough Neville
Published: March 2009

Atomic Energy of Canada Ltd. (AECL) has very successful experience in implementing new construction methods at the Qinshan (Phase III) twin unit CANDU 6 plant in China. This paper examines the construction method that must be implemented during the conceptual design phase of a project if short construction schedules are to be met. A project schedule of 48 months has been developed for the nth unit of NG (Next Generation) CANDU with a 42 month construction period from 1st Concrete to In-Service. An overall construction strategy has been developed involving paralleling project activities that are normally conducted in series. Many parts of the plant will be fabricated as modules and be installed using heavy lift cranes. The Reactor Building (RB), being on the critical path, has been the focus of considerable assessment, looking at alternative ways of applying the construction strategy to this building. A construction method has been chosen which will result in excess of 80% of internal work being completed as modules or as very streamlined traditional construction. This method is being further evaluated as the detailed layout proceeds. Other areas of the plant have been integrated into the schedule and new construction methods are being applied to these so that further modularization and even greater paralleling of activities will be achieved. It is concluded that the optimized construction method is a requirement, which must be implemented through all phases of design to make a 42 month construction schedule a reality. If the construction methods are appropriately chosen, the schedule reductions achieved will make nuclear more competitive.
Detailed Multi Canister Release Model of Radionuclides in High Level Radioactive Waste Repository Using Wavelet Galerkin Method
Authors: Nasif Hesham R. , Neyama Atsushi
Published: March 2009

This work develops a model to calculate the radionuclides release from a repository for high level radioactive waste, taking into account multiple-canister interface. Once the overpack loses its integrity, the waste glass starts to dissolve by porewater in the bentonite buffer. Bentonite is expected to have hydraulic conductivity more than three orders of magnitude less than that of the surrounding rocks. The migrating nuclide from the buffer region is transported in the near field granite host rock, then releases to the far field of the repository. A mass concentration calculation in the far field of the repository is also included in the model. The model is diffusion-advection model. The model is solved using wavelet Galerkin method (WGM). The model is devised to be fast and compact due to the compactly supported property of the Daubechies’ wavelet. Since the scaling functions are compactly supported only a finite number of the connection coefficients are nonzero. The resultant matrix has block diagonal structure, which can be inverted easily. We tested our model for a try of canisters contains 200 canisters. The results show well agreements with the results obtained from the analytic solution with a proper selection of wavelet-dilation order pairs.
Risk and Performance Technologies: Identifying the Keys to Successful Implementation
Authors: McClain Lynn , Smith Art , O’Regan Patrick
Published: March 2009

The nuclear power industry has been utilizing risk and performance based technologies for over thirty years. Applications of these technologies have included risk assessment (e.g. Individual Plant Examinations), burden reduction (e.g. Risk-Informed Inservice Inspection, RI-ISI) and risk management (Maintenance Rule, 10CFR50.65). Over the last five to ten years the number of risk-informed (RI) burden reduction initiatives has increased. Unfortunately, the efficiencies of some of these applications have been questionable. This paper investigates those attributes necessary to support successful, cost-effective RI-applications. The premise to this paper is that by understanding the key attributes that support one successful application, insights can be gleaned that will streamline/coordinate future RI-applications. This paper is an extension to a paper presented at the Pressure Vessel and Piping (PVP-2001) Conference. In that paper, a number issues and opportunities were identified that needed to be assessed in order to support future (and efficient) RI-applications. It was noted in the paper that a proper understanding and resolution of these issues will facilitate implementation of risk and performance technology in the operation, maintenance and design disciplines. In addition, it will provide the foundation necessary to support regulatory review and approval.
Recent Issues in Risk-Informed Inservice Inspection of Piping
Authors: Ali Syed A. , Dinsmore Stephen
Published: March 2009

Issues related to RI-ISI that have arisen recently include: augmented ISI programs and the synergistic effects when multiple degradation mechanisms exist in a segment; start of the RI-ISI program and details of merging the RI-ISI program with the existing ASME XI program when the RI-ISI program does not start at the beginning of an interval; updates to RI-ISI programs and living program criteria; criteria to be used for additional examinations when ISI reveals unacceptable flaws; application of RI-ISI methodology to inservice examination (ISI) of break exclusion region (BER) piping.
Macroscopic Streaming Associated With Vertical, Cyclic Motion of Interface Confined in a Cylindrical Enclosure
Authors: Shimizu Jun , Ito Takahiro , Tsuji Yoshiyuki , Kukita Yutaka
Published: March 2009

The interface between overlaid fluids can become unstable when the fluids are excited vertically. The instability caused by the variation in the vertical acceleration is known by the name of the Faraday waves. Ito et al. (1999) studied a combined excitation problem where the fluids were excited vertically in a stationary cylinder while the interface motion was restricted by the mobility of the fluid-fluid-wall contact line. They found that, under such circumstances, the symmetric fundamental mode grows on the interface, even for excitation amplitude and frequency falling in the stable regime of the Faraday wave instability. Furthermore, they found that the contact line exhibits stick-slip-like motion for the combination of fluids and wall material used in their experiments (water and kerosene oil in a cylinder made of acrylic resin). In this paper, we describe and discuss the fluid motions associated with the excitation of fluids and interface wave. It is shown that a unidirectional flow (macroscopic streaming) is induced below the center of the interface when it is excited vertically to produce axisymmetric wave of large amplitudes. This unidirectional, jet-like flow induces a large-scale recirculating flow which extends several cylinder diameters away from the interface, a spatial scale considerably greater than the wavelength or amplitude of the interface waves, and has a time scale much greater than the excitation interval. It is shown that the phase angle between the wave-induced fluid motion and the fluid motion associated with the viscous force along the interface plays an important role in establishing the large scale stream motion of the fluids.
FR Number Effect on Downcomer Flowpattern Development in Cold Leg Injection Scenarios
Authors: Gavritas Mirela , Woods Brian G.
Published: March 2009

In addition to acquiring data for code verification, the recent rapid Boron dilution (RBD) test program at the University of Maryland 2×4 Thermalhydraulic Loop Facility (UM 2×4 Loop) aimed to resolve several issues related to physical phenomena that can affect the reboration of a boron dilute slug as it travels to the core. Among these issues, confirmation was sought that buoyancy plays a minimal role in the mixing of the slug as it travels through the downcomer. The tests showed, however, that the Froude (Fr) number substantially impacts the downcomer flowpattern. The slug distribution in the downcomer clearly changes from penetrating downwards along a single jet when the Fr number is smaller than approximately 6 to splitting into two jets that form a stagnation region under the injection site when Fr exceeds approximately 10. This observation was initially made evaluating the evolution histories of Fr numbers throughout individual tests. Closer examination of a broad family of tests showed that the flowpattern can actually be predicted based on Fr numbers determined from initial and boundary test conditions. Even though global figures of merit for mixing, e.g., azimuthally averaged scalar descriptors of mixing at a horizontal level of the downcomer, are only weakly affected by Fr number changes, this finding has substantial implications to the computational assessment of rapid Boron-dilution (RBD) consequences. A thorough understanding of the flow field is an essential prerequisite in computational fluid dynamics modeling.
Design of Material Strength Test in Lead-Bismuth Flow
Authors: Kondo Masatoshi , Hata Koji , Takahashi Minoru
Published: March 2009

Liquid lead and lead-bismuth have drawn the attention as one of the candidate coolants of the fast breeder reactors (FBRs), and the accelerator driven transmutation systems (ADSs). In order to use the coolant to the systems, the physical and chemical characteristics of the heavy metals are necessary. This plan has been proposed for the strength test of materials in the liquid metal surroundings. The lead-bismuth circulation loop with the strength test has been designed, and the strength test of candidate materials has been planned.
Characteristics of Transient Boiling Heat Transfer
Authors: Liu Wei , Monde Masanori , Mitsutake Y.
Published: March 2009

In this paper, one dimensional inverse heat conduction solution is used for a measurement of pool boiling curve. The experiments are performed under atmospheric pressure for copper, brass, carbon steel and gold. Boiling curves, including unsteady transition boiling region, are found can be traced fairly well from a simple experiment system by solving inverse heat conduction solution. Boiling curves for steady heating and transient heating, for heating process and cooling process are compared. Surface behavior around CHF point, transition boiling and film-boiling regions are observed by using a high-speed camera. The results show the practicability of the inverse heat conduction solution in tracing boiling curve and thereby supply us a new way in boiling heat transfer research.
PIV and LIF Measurements of Flow in the Vicinity of Moving Interface
Authors: Shimizu Jun , Ito Takahiro , Tsuji Yoshiyuki , Kukita Yutaka
Published: March 2009

The interface between overlaid fluids can become unstable when the fluids are excited vertically. Ito et al. (1999) studied a combined excitation problem where the fluids were excited vertically in a stationary cylinder while the interface motion was restricted by the mobility of the fluid-fluid-wall contact line. They found that the contact line exhibits stick-slip-like motion for the combination of fluids and wall material used in their experiments (water and kerosene oil in a cylinder made of acrylic resin). The flow above and beneath the interface is visualized by adding small particles. A vertical, diametral cross section of the test section is illuminated by a 509-nm Argon laser sheet. The experimental data presented in this paper were taken using ‘EXPANCEL’ particle tracer with a typical diameter of 10 µm, added to the water above and beneath the interface. Pictures are taken by a high-speed CCD camera at a rate of 120 frame/s. Each uninterlaced (120 frame/s) video frame is divided into 640 × 480 pixels for image processing. The fluid velocity is obtained for each 2.95 mm × 2.95 mm area by using the PIV technique. Visualization studies have revealed that the nonuniform velocity distribution above and below the interface extends to a much greater depth than the wave amplitude. Streamlines were taken by using Rhodamine-B fluorescent dye which was added to water beneath the interface and excited with an Ar laser fan beam, with a CCD camera.
Study on the Interaction of Molten Metal and a Coolant
Authors: Kizu Tetsuya , Abe Yutaka , Nariai Hideki , Chitose Keiko , Koyama Kazuya
Published: March 2009

In a core disruptive accident (CDA) of a fast breeder reactor, the post accident heat removal (PAHR) is crucial for the accident mitigation. The molten core material should be cooled by the inventory of the coolant in the lower plenum of the reactor vessel. It is still unknown whether two phase cooling can be expected during molten core material and coolant interaction. The purpose of the present study is to experimentally clarify the cooling capability of the coolant for the molten material including two phase boiling. In the experiment, simulated molten metal jet is injected into water to experimentally obtain the visualized information of the fragmentation and boiling phenomena during PAHR in CDA.
In-Vessel Retention Modeling Capabilities of SCDAP/RELAP5-3D©
Authors: Knudson D. L. , Rempe J. L.
Published: March 2009

Molten core materials may relocate to the lower head of a reactor vessel in the latter stages of a severe accident. Under such circumstances, in-vessel retention (IVR) of the molten materials is a vital step in mitigating potential severe accident consequences. Whether IVR occurs depends on the interactions of a number of complex processes including heat transfer inside the accumulated molten pool, heat transfer from the molten pool to the reactor vessel (and to overlying fluids), and heat transfer from exterior vessel surfaces. SCDAP/RELAP5-3D© has been developed at the Idaho National Engineering and Environmental Laboratory to facilitate simulation of the processes affecting the potential for IVR, as well as processes involved in a wide variety of other reactor transients. In this paper, current capabilities of SCDAP/RELAP5-3D© relative to IVR modeling are described and results from typical applications are provided. In addition, anticipated developments to enhance IVR simulation with SCDAP/RELAP5-3D© are outlined.
Development of a Risk-Informed IST Program at Palisades Using Top Event Prevention
Authors: White Robert A. , Blanchard David P.
Published: March 2009

At the Palisades Nuclear Power Plant, a review of systems, structures and components is being performed for a variety of risk-informed applications. Among these applications is the In-Service Testing program developed under Section XI of the ASME Boiler and Pressure Vessel Code. In reviewing the scope of the IST program, a relatively new risk ranking technique is being utilized called Top Event Prevention (TEP). TEP differs from more traditional methods of risk ranking in that it uses defense-in-depth methods to select what SSCs are important to safety. The results of the TEP analysis are also somewhat unique as compared to more traditional approaches in that combinations of equipment important to safety are identified as opposed to determining importance one component at a time. In addition, entire paths or trains of equipment are identified as being required to manage safety. Furthermore, the components identified in the selected trains are minimal. That is, TEP identifies the minimum set of equipment modeled in the PRA that is necessary to manage safety. Because TEP provides a structured, deterministic approach to selection of components that are important to managing safety, consideration is being given to classifying pumps and valves into one of three safety categories; high safety significant components, low safety significant components and a third non safety significant category. The first two categories of safety significance are similar to those already defined in Regulatory Guide 1.175 [1], and will identify where current testing methods remain appropriate while suggesting those components for which testing intervals can be extended. The third or non-safety significant category has been established to identify those pumps and valves to which the PRA and safety are insensitive. Preliminary results from the TEP analysis of the Palisades IST scope suggest that of the more than 500 pumps and valves modeled in the PRA, just under one third are not important from a defense-in-depth perspective. Probabilistic testing of these approximately 140 components shows that risk as modeled by the PRA is not dependent on the reliability of these components. This suggests that the PRA is relatively insensitive to the reliability of these components collectively and that they can be considered as candidates for significant relaxation of testing requirements, possibly including exclusion from the formal IST program.
Practical Approaches to Addressing the Evolving Perception of Terrorist Threats to Nuclear Power Plants
Authors: Butcher E. J. , Roe J. W.
Published: March 2009

The September 11, 2001 terrorist attack on the World Trade Center and subsequent events has effected perceptions of the terrorist threat to the U.S. in general, and nuclear power plants in particular. These concerns have given rise to calls by government and private orga nizations for reevaluations of both the nature of the threat and protection against it. This paper suggests a general framework for a balanced approach to these reevaluations and highlights some practical and cost effective approaches for improving nuclear power plant safeguards protection.
A Complete Piping Analysis With Thermal Stratification Loads
Authors: Dong Milton , Lee Hong Ming , Chern Chii
Published: March 2009

The U. S. Nuclear Regulatory Commission (USNRC) had issued Bulletins 88-08, 88-11, 89-90, and 93-38 to address the concerns and problems due to thermal stratification loading during the life span of normal plant operation. The thermal stratification condition typically will cause pipe to bow in on a long horizontal segment. These conditions have not been commonly considered in piping design. However, the additional thermal cyclic stresses and loads due to these conditions could lead to the fatigue damage of the piping components and the failures of pipe supports. Analyzing the effects of thermal stratification loads can be very cumbersome if it is not a built-in functionality of the analysis program. Thus in response to the recent increase in such cases we have incorporated this feature in our piping stress computer program. A stress engineer can now define the thermal stratification conditions easily and the program will compute the pipe stresses and pipe support loads automatically as one of the load cases. The program then combines the thermal stratification load cases with other load cases as required in accordance with the load histogram to determine the cumulative fatigue damage of the piping system. The thermal cyclic stresses are evaluated in accordance with the design rules of Nuclear Class 1 piping components provided in NB-3650 of ASME section III Code. This paper presents the method, modeling and validation for implementing the functionality of analyzing thermal stratification loads in a computer program, as well as an application on an actual piping system as an illustration.
Experimental Feedback on Sodium Loop Decommissioning at the CEA
Authors: Vinoche O. , Rodriguez G.
Published: March 2009

The aim of this paper is to present experimental feedback on sodium loop dismantling techniques at the CEA (The French Atomic Energy Commission) and to offer recommendations for the decommissioning of Fast Breeder Reactor secondary sodium loops. This study is divided into several parts which correspond to the different stages of a dismantling system. It is based on acquired CEA decommissioning experience which primarily concerns the following: the decommissioning of RAPSODIE (France’s first Fast Breeder Reactor), the PHENIX reactor secondary loop replacement, the sodium loop decommissioning carried out by the Laboratory of Sodium Technologies and Treatment, and several technical documents. This paper deals with the main results of this survey. First, a comparison of 8 pipe-cutting techniques is made, taking into account speed in cutting, reliability, dissemination, fire risk due to the presence of sodium, cutting depth, and different types of waste (empty pipes, sodium-filled pipes, tanks...). This comparison has led us to recommend the use of an alternative saw or a chain saw rather than the use of the plasma torch or grinder. Different techniques are recommended depending on if they are on-site, initial cuttings or if they are to be carried out in a specially-designed facility referred to hereafter as “the cutting building”. After the cutting stage, the sodium waste must be processed with water to become an ultimate stable waste. Four treatment processes are compared with different standards: speed, cost, low activity adaptability and “large sodium quantity” adaptability. Recommendations are also made for reliable storage, and for the general dismantling system organization. Last, calculations are presented concerning a complete dismantling facility prototype capable of treating large amounts of sodium.
Re-Assessment of Nitride Fuel Potential in the Current Context of the Nuclear Industry
Authors: Reynaud Sylvie M. , Peddicord Kenneth L.
Published: March 2009

In recent years, there has been a renewal of interest in nitride fuels throughout the international community. The new challenges met by the nuclear industry, which include greater safety margin and the question of the waste management, have resulted in active research programs in next generation fast spectrum reactors and waste transmutation systems. Through these programs, nitride fuel has emerged as one of the most promising advanced fuels, thanks to their numerous favorable properties.
Non-Destructive Techniques in the Tacis and Phare Nuclear Safety Programmes
Authors: Bie`th Michel
Published: March 2009

Decisions regarding the verification of design plant lifetime and potential license renewal periods involve a determination of the component and circuit condition. In Service Inspection of key reactor components becomes a crucial consideration for continued safe plant operation. The determination of the equipment properties by Non Destructive Techniques during periodic intervals is an important aspect of the assessment of fitness-for-service and safe operation of nuclear power plants The Tacis and Phare were established since 1991 by the European Union as support mechanisms through which projects could be identified and addressed satisfactorily. In Nuclear Safety, the countries mainly concerned are Russia, Ukraine, Armenia, and Kazakhstan for the Tacis programme, and Bulgaria, Czech Republic, Hungary, Slovak Republic, Lithuania, Romania and Slovenia for the Phare programme. The Tacis and Phare programs concerning the Nuclear Power Plants consist of: • On Site Assistance and Operational Safety, • Design Safety, • Regulatory Authorities, • Waste management, and are focused on reactor safety issues, contributing to the improvement in the safety of East European reactors and providing technology and safety culture transfer. The main parts of these programmes are related to the On-Site Assistance and to the Design Safety of VVVER and RBMK Nuclear power plants where Non Destructive Techniques for In Service Inspection of the primary circuit components are addressed.
Manually-Operated Crate Dismantlement System for Los Alamos National Laboratory
Authors: Laffitte John , Lagos Leo , Morales Miguel
Published: March 2009

Los Alamos National Laboratory currently possesses between 500 and 800 fiberglass-reinforced plywood crates that contain hazardous materials that need to be decontaminated. To access the hazardous material, a system is needed to dismantle the crate. Currently, crates are dismantled by workers using hand-held tools. This technique has numerous disadvantages. One disadvantage is that it is difficult for a worker to hold the tool for an extended period of time in the awkward angles and positions necessary to fully size-reduce the crate. Other disadvantages of using hand tools include managing power cords and vacuum hoses, which become entangled or can act as tripping hazards. In order to improve the crate opening and size-reduction task, Florida International University’s Hemispheric Center for Environmental Technology (HCET) is developing a manually operated crate dismantlement system. This versatile system is expected to greatly increase worker efficiency while decreasing fatigue and the possibility of accidents.
Main Steam Line Technical Design Improvement Using a More Detailed Piping Analysis
Authors: Revesz Zsolt
Published: March 2009

The paper describes a case in which with more detailed analysis of the seismic loads and with more elaborated, more accurate model the Main Steam Line of a 1000 MWe class nuclear power plant with BWR has been redesigned. Re-design and re-qualification has resulted in a new piping configuration with significantly reduced number of installed snubbers, and in a more simple support system. The analysis of the piping system has been repeated over twenty years after the original work, whereas the main differences consisted of changes in the piping code and the use of the abundant computational resources available today — besides revision of the earthquake analysis of the buildings. Final recommendation consisted in two suggested configuration change packages. One with a significant reduction in the number of earthquake restraints snubbers) with no need to further analyze elements of the support structure before implementation. A second one with an additional possibility to reduce the number of snubbers, but requiring analysis of piping support structures to see if the higher loads are still allowable or else if a reasonable hardware changes would reinforce structural elements to carry the new load.
Drought Sensitivity of the Amazon Rainforest
Authors: Phillips Oliver L. , Aragão Luiz E. O. C. , Lewis Simon L. , Fisher Joshua B. , Lloyd Jon , López-González Gabriela , Malhi Yadvinder , Monteagudo Abel , Peacock Julie , Quesada Carlos A. , van der Heijden Geertje , Almeida Samuel , Amaral Iêda , Arroyo Luzmila , Aymard Gerardo , Baker Tim R. , Bánki Olaf , Blanc Lilian , Bonal Damien , Brando Paulo , Chave Jerome , de Oliveira Átila Cristina Alves , Cardozo Nallaret Dávila , Czimczik Claudia I. , Feldpausch Ted R. , Freitas Maria Aparecida , Gloor Emanuel , Higuchi Niro , Jiménez Eliana , Lloyd Gareth , Meir Patrick , Mendoza Casimiro , Morel Alexandra , Neill David A. , Nepstad Daniel , Patiño Sandra , Peñuela Maria Cristina , Prieto Adriana , Ramírez Fredy , Schwarz Michael , Silva Javier , Silveira Marcos , Thomas Anne Sota , Steege Hans ter , Stropp Juliana , Vásquez Rodolfo , Zelazowski Przemyslaw , Dávila Esteban Alvarez , Andelman Sandy , Andrade Ana , Chao Kuo-Jung , Erwin Terry , Di Fiore Anthony , C. Eurídice Honorio , Keeling Helen , Killeen Tim J. , Laurance William F. , Cruz Antonio Peña , Pitman Nigel C. A. , Vargas Percy Núñez , Ramírez-Angulo Hirma , Rudas Agustín , Salamão Rafael , Silva Natalino , Terborgh John , Torres-Lezama Armando
Published: March 2009

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 × 10
15
to 1.6 × 10
15
grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.
Phase-Sensitive Observation of a Spin-Orbital Mott State in Sr
2
IrO
4
Authors: Kim B. J. , Ohsumi H. , Komesu T. , Sakai S. , Morita T. , Takagi H. , Arima T.
Published: March 2009

Measurement of the quantum-mechanical phase in quantum matter provides the most direct manifestation of the underlying abstract physics. We used resonant x-ray scattering to probe the relative phases of constituent atomic orbitals in an electronic wave function, which uncovers the unconventional Mott insulating state induced by relativistic spin-orbit coupling in the layered 5
d
transition metal oxide Sr
2
IrO
4
. A selection rule based on intra-atomic interference effects establishes a complex spin-orbital state represented by an effective total angular momentum = 1/2 quantum number, the phase of which can lead to a quantum topological state of matter.
Species Response to Environmental Change: Impacts of Food Web Interactions and Evolution
Authors: Harmon Jason P. , Moran Nancy A. , Ives Anthony R.
Published: March 2009

How environmental change affects species abundances depends on both the food web within which species interact and their potential to evolve. Using field experiments, we investigated both ecological and evolutionary responses of pea aphids (
Acyrthosiphon pisum
), a common agricultural pest, to increased frequency of episodic heat shocks. One predator species ameliorated the decrease in aphid population growth with increasing heat shocks, whereas a second predator did not, with this contrast caused by behavioral differences between predators. We also compared aphid strains with stably inherited differences in heat tolerance caused by bacterial endosymbionts and showed the potential for rapid evolution for heat-shock tolerance. Our results illustrate how ecological and evolutionary complexities should be incorporated into predictions of the consequences of environmental change for species' populations.
Rare Variants of
IFIH1
, a Gene Implicated in Antiviral Responses, Protect Against Type 1 Diabetes
Authors: Nejentsev Sergey , Walker Neil , Riches David , Egholm Michael , Todd John A.
Published: March 2009

Genome-wide association studies (GWASs) are regularly used to map genomic regions contributing to common human diseases, but they often do not identify the precise causative genes and sequence variants. To identify causative type 1 diabetes (T1D) variants, we resequenced exons and splice sites of 10 candidate genes in pools of DNA from 480 patients and 480 controls and tested their disease association in over 30,000 participants. We discovered four rare variants that lowered T1D risk independently of each other (odds ratio = 0.51 to 0.74;
P
= 1.3 × 10
–3
to 2.1 × 10
–16
) in
IFIH1
(
interferon induced with helicase C domain 1
), a gene located in a region previously associated with T1D by GWASs. These variants are predicted to alter the expression and structure of IFIH1 [MDA5 (melanoma differentiation-associated protein 5)], a cytoplasmic helicase that mediates induction of interferon response to viral RNA. This finding firmly establishes the role of
IFIH1
in T1D and demonstrates that resequencing studies can pinpoint disease-causing genes in genomic regions initially identified by GWASs.
CD24 and Siglec-10 Selectively Repress Tissue Damage–Induced Immune Responses
Authors: Chen Guo-Yun , Tang Jie , Zheng Pan , Liu Yang
Published: March 2009

Patten recognition receptors, which recognize pathogens or components of injured cells (danger), trigger activation of the innate immune system. Whether and how the host distinguishes between danger- versus pathogen-associated molecular patterns remains unresolved. We report that CD24-deficient mice exhibit increased susceptibility to danger- but not pathogen-associated molecular patterns. CD24 associates with high mobility group box 1, heat shock protein 70, and heat shock protein 90; negatively regulates their stimulatory activity; and inhibits nuclear factor κB (NF-κB) activation. This occurs at least in part through CD24 association with Siglec-10 in humans or Siglec-G in mice. Our results reveal that the CD24–Siglec G pathway protects the host against a lethal response to pathological cell death and discriminates danger- versus pathogen-associated molecular patterns.
Many Worlds in Tiny Grains
Authors: Holman Rob
Published: March 2009

Sand
. The Never-Ending Story.
By Michael Welland
. University of California Press, Berkeley, 2009. 374 pp. $24.95, £17.95. ISBN 9780520254374.
Exomic Sequencing Identifies
PALB2
as a Pancreatic Cancer Susceptibility Gene
Authors: Jones Siân , Hruban Ralph H. , Kamiyama Mihoko , Borges Michael , Zhang Xiaosong , Parsons D. Williams , Lin Jimmy Cheng-Ho , Palmisano Emily , Brune Kieran , Jaffee Elizabeth M. , Iacobuzio-Donahue Christine A. , Maitra Anirban , Parmigiani Giovanni , Kern Scott E , Velculescu Victor E. , Kinzler Kenneth W. , Vogelstein Bert , Eshleman James R. , Goggins Michael , Klein Alison P.
Published: March 2009

Through complete sequencing of the protein-coding genes in a patient with familial pancreatic cancer, we identified a germline, truncating mutation in
PALB2
that appeared responsible for this patient's predisposition to the disease. Analysis of 96 additional patients with familial pancreatic cancer revealed three distinct protein-truncating mutations, thereby validating the role of
PALB2
as a susceptibility gene for pancreatic cancer.
PALB2
mutations have been previously reported in patients with familial breast cancer, and the PALB2 protein is a binding partner for BRCA2. These results illustrate that complete, unbiased sequencing of protein-coding genes can lead to the identification of a gene responsible for a hereditary disease.
NF-κB p50 Plays Distinct Roles in the Establishment and Control of Murine Gammaherpesvirus 68 Latency
Authors: Krug Laurie T. , Collins Christopher M. , Gargano Lisa M. , Speck Samuel H.
Published: March 2009

NF-κB signaling is critical to the survival and transformation of cells infected by the human gammaherpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. Here we have examined how elimination of the NF-κB transcription factor p50 from mice affects the life cycle of murine gammaherpesvirus 68 (MHV68). Notably, mice lacking p50 in every cell type were unable to establish a sufficiently robust immune response to control MHV68 infection, leading to high levels of latently infected B cells detected in the spleen and persistent virus replication in the lungs. The latter correlated with very low levels of virus-specific immunoglobulin G (IgG) in the infected p50−/−mice at day 48 postinfection. Because the confounding impact of the loss of p50 on the host response to MHV68 infection prevented a direct analysis of the role of this NF-κB family member on MHV68 latency in B cells, we generated and infected mixed p50+/+/p50−/−bone marrow chimeric mice. We show that the chimeric mice were able to control acute virus replication and exhibited normal levels of virus-specific IgG at 3 months postinfection, indicating the induction of a normal host immune response to MHV68 infection. However, in p50+/+/p50−/−chimeric mice the p50−/−B cells exhibited a significant defect compared to p50+/+B cells in supporting MHV68 latency. In addition to identifying a role for p50 in the establishment of latency, we determined that the absence of p50 in a subset of the hematopoietic compartment led to persistent virus replication in the lungs of the chimeric mice, providing evidence that p50 is required for controlling virus reactivation. Taken together, these data demonstrate that p50 is required for immune control by the host and has distinct tissue-dependent roles in the regulation of murine gammaherpesvirus latency during chronic infection.
Unraveling Viral Interleukin-6 Binding to gp130 and Activation of STAT-Signaling Pathways Independently of the Interleukin-6 Receptor
Authors: Adam Nina , Rabe Björn , Suthaus Jan , Grötzinger Joachim , Rose-John Stefan , Scheller Jürgen
Published: March 2009

Human herpesvirus 8 encodes a viral version of interleukin-6 (vIL-6) which shows 25% sequence homology with human IL-6. In contrast to human IL-6, which first binds to the IL-6 receptor (IL-6R) and only subsequently associates with the signal transducing receptor subunit gp130, vIL-6 has been shown to directly bind to gp130 without the need of IL-6R. As a functional consequence, vIL-6 can activate far more target cells in the body since all cells express gp130, but only cells such as hepatocytes and some leukocytes express IL-6R. We sought to understand which amino acid sequences within the vIL-6 protein were responsible for its ability to bind and activate gp130 independent of IL-6R. As a first approach, we constructed chimeric IL-6 proteins in which all known gp130 interacting sites (sites II and III) were sequentially transferred from vIL-6 into the human IL-6 protein. To our surprise, human IL-6 carrying all gp130 interacting sites from vIL-6 did not show IL-6R-independent gp130 activation. Even more surprisingly, the loop between helix B and C of vIL-6, clearly shown in the crystal structure not to be in contact with gp130, is indispensable for direct binding to and activation of gp130. This points to an IL-6R induced change of site III conformation in human IL-6, which is already preformed in vIL-6. These data indicate a novel activation mechanism of human IL-6 by the IL-6R that will be important for the construction of novel hyperactive cytokine variants.
A Yeast Glycoprotein Shows High-Affinity Binding to the Broadly Neutralizing Human Immunodeficiency Virus Antibody 2G12 and Inhibits gp120 Interactions with 2G12 and DC-SIGN
Authors: Luallen Robert J. , Fu Hu , Agrawal-Gamse Caroline , Mboudjeka Innocent , Huang Wei , Lee Fang-Hua , Wang Lai-Xi , Doms Robert W. , Geng Yu
Published: March 2009

The human immunodeficiency virus type 1 (HIV-1) envelope (Env) protein contains numerous N-linked carbohydrates that shield conserved peptide epitopes and promote
trans
infection by dendritic cells via binding to cell surface lectins. The potent and broadly neutralizing monoclonal antibody 2G12 binds a cluster of high-mannose-type oligosaccharides on the gp120 subunit of Env, revealing a conserved and highly exposed epitope on the glycan shield. To find an effective antigen for eliciting 2G12-like antibodies, we searched for endogenous yeast proteins that could bind to 2G12 in a panel of
Saccharomyces cerevisiae
glycosylation knockouts and discovered one protein that bound weakly in a Δ
pmr1
strain deficient in hyperglycosylation. 2G12 binding to this protein, identified as Pst1, was enhanced by adding the Δ
mnn1
deletion to the Δ
pmr1
background, ensuring the exposure of terminal α1,2-linked mannose residues on the D1 and D3 arms of high-mannose glycans. However, optimum 2G12 antigenicity was found when Pst1, a heavily N-glycosylated protein, was expressed with homogenous Man
8
GlcNAc
2
structures in Δ
och1
Δ
mnn1
Δ
mnn4
yeast. Surface plasmon resonance analysis of this form of Pst1 showed high affinity for 2G12, which translated into Pst1 efficiently inhibiting gp120 interactions with 2G12 and DC-SIGN and blocking 2G12-mediated neutralization of HIV-1 pseudoviruses. The high affinity of the yeast glycoprotein Pst1 for 2G12 highlights its potential as a novel antigen to induce 2G12-like antibodies.
Herpes Simplex Virus Type 1 Regulatory Protein ICP0 Aids Infection in Cells with a Preinduced Interferon Response but Does Not Impede Interferon-Induced Gene Induction
Authors: Everett Roger D. , Orr Anne
Published: March 2009

Several independent lines of evidence indicate that interferon-mediated innate responses are involved in controlling herpes simplex virus type 1 (HSV-1) infection and that the viral immediate-early regulatory protein ICP0 augments HSV-1 replication in interferon-treated cells. However, this is a complex situation in which the experimental outcome is determined by the choice of multiplicity of infection and cell type and by whether cultured cells or animal models are used. It is now known that neither STAT1 nor interferon regulatory factor 3 (IRF-3) play essential roles in the replication defect of ICP0-null mutant HSV-1 in cultured cells. This study set out to investigate the specific role of ICP0 in HSV-1 resistance to the interferon defense. We have used a cell line in which ICP0 expression can be induced at levels similar to those during the early stages of a normal infection to determine whether ICP0 by itself can interfere with interferon or IRF-3-dependent signaling and whether ICP0 enables the virus to circumvent the effects of interferon-stimulated genes (ISGs). We found that the presence of ICP0 was unable to compromise ISG induction by either interferon or double-stranded RNA. On the other hand, ICP0 preexpression reduced but did not eliminate the inhibitory effects of ISGs on HSV-1 infection, with the extent of the relief being highly dependent on multiplicity of infection. The results are discussed in terms of the relationships between ICP0 and intrinsic and innate antiviral resistance mechanisms.
APPLYING ASSOCIATION MINING TO CHANGE PROPAGATION
Authors: YU LIGUO , SCHACH STEPHEN R.
Published: March 2009

A software system evolves as changes are made to accommodate new features and repair defects. Software components are frequently interdependent, so changes made to one component can result in changes having to be made to other components to ensure that the system remains consistent; this is called change propagation. Accurate detection of change propagation is essential for software maintenance, which can be aided by accurate prediction of change propagation. In this paper, we study change propagation in three leading open-source software products: Linux, FreeBSD, and Apache HTTP Server. We use association rules-based data-mining techniques to detect change-propagation rules from the product version history. These rules are evaluated with respect to different training data sets and different test data sets. We discuss the applicability of using association-rule mining for change propagation, and several related issues. We find that a challenging issue in association-rule mining, concept drift, exists in software systems. Concept drift complicates the task of change-propagation prediction and requires special approaches, different from currently-used techniques for predicting change propagation.