bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Existence of Circle-Point and Center-Point Circles for Three-Precision-Point-Dyad Synthesis
Authors: Loerch R. J. , Erdman A. G. , Sandor G. N.
Published: November 2010

A graphical method is developed for expressing solutions to all possible revolute dyad, three finitely separated position synthesis problems, where any two rotational displacements are prescribed. Also, cases are discussed where two positions and one velocity are prescribed. The three-precision-point solutions are shown to be represented by circular loci of fixed and moving dyad pivots that are derived from an analytical treatment based on bilinear transformation of the synthesis equations. The superposition of two three-position dyad problems with two common positions yields points on the four-precision-point Burmester curves satisfying both problems. A new alternative explanation for the classical Burmester curve construction is offered. Regions of the plane are found where dyad moving pivots cannot exist for a given problem. Computer graphics output is used to demonstrate several typical solutions.
Elliptical Crack in a Finite-Thickness Plate Subjected to Tensile and Bending Loading
Authors: Shah R. C. , Kobayashi A. S.
Published: November 2010

Stress intensity magnification factors for an elliptical crack embedded in a finite thickness plate subjected to tensile and bending loading are estimated by judicious use of analytical results obtained previously. These analytical results involve the stress intensity magnification factors for an embedded elliptical crack approaching the free surface of a semi-infinite solid and pressurized by a constant or by a linearly varying pressure. The resultant stress intensity magnification factors for the elliptical crack in a plate are presented in graphical forms for various crack aspect ratios, eccentricity, and proximity factors.
Nonlinear Dynamic Analysis of Axisymmetric Solids by the Finite Element Method
Authors: Hartzman M.
Published: November 2010

A method for calculating the dynamic response of deformable axisymmetric solids, subjected to time-dependent axisymmetric loads is described. The nonlinearities considered in this analysis include material nonlinearity (elastic-plastic behavior) and geometric nonlinearity, which includes finite deformation. The finite-element method is applied to approximate the continuum by a lumped-mass system connected by axisymmetric elements. The equations of motion are solved by applying a step-by-step numerical technique. The analysis is illustrated by application to the collapse of a built-in spherical dome with varying thickness and to the impact of a cylinder against a rigid wall. Close agreement is obtained between the results from the present technique and results obtained from the literature.
Upper Bounds for Accumulated Strains Due to Creep Ratcheting
Authors: O’Donnell W. J. , Porowski J.
Published: November 2010

A rigorous method of bounding both the total accumulated strain and the strain ranges due to cyclic operation in the creep regime is presented. These limits can be obtained from the results of purely elastic stress analyses. The basic problem of a cylindrical vessel under internal pressure subjected to cyclic thermal stresses is solved in detail. The results are presented in graphical form suitable for design purposes.
Plastic Collapse Loads for Pipe Elbows Using Inelastic Analysis
Authors: Mello R. M. , Griffin D. S.
Published: November 2010

The results of an inelastic analysis are used to predict plastic collapse loads for in-plane bending of several pipe elbows. The analysis is made using a nonlinear finite element computer program which takes into account the effects of material strain hardening, stress redistribution, and ovalization of the elbow cross section. Various methods are used to determine plastic collapse loads based on the calculated load-deformation curves. The predicted collapse loads are compared to collapse loads determined by limit analysis and the method described for plastic analysis in Section III, Appendix F, of the ASME Boiler and Pressure Vessel Code. It is concluded that the current Code definition of collapse load is overly conservative for structural materials typical of high temperature application, and that the 0.2 percent offset method or the 2 times the angle of linear response method produce more realistic results.
Computer Graphics for 3-D Finite Element Models
Authors: Kirchhoff L. W.
Published: November 2010

A description is given of a computer graphics program for detecting errors in three-dimensional finite element models and reducing finite element analysis data to a usable form. An efficient hidden line algorithm for mixed sets of polygons and polyhedra is presented together with a general line classification scheme. They are used to produce the variety of plots necessary to detect errors in the model. They also provide an “uncluttered” surface for displaying stress, temperature, and displacement data.
Estimation of Crack Extension in a Piping Elbow Using Fracture Mechanics Techniques
Authors: James L. A.
Published: November 2010

The extension of a hypothetical crack in a piping elbow under fatigue loadings at elevated temperature is estimated using the analysis techniques of linear-elastic fracture mechanics. The assumptions and approximations concerning the stress and loading conditions, expected in-service operational environment, and material properly behavior that must be made in order to complete the analysis are discussed in detail.
Flow-Induced Forces on a Cylinder for Different Wall Confinements at High Reynolds Numbers (3.5×105)<Re<(1.2×106)
Authors: Chen P. Y. , Doepker P. E.
Published: November 2010

The nearness of a cylinder to a wall has an important effect on the flow-induced forces exerted on that cylinder, particularly when the cylinder is relatively large compared to the cross section of the flow channel. This paper describes an investigation of wall interference effects that occur when crossflow-induced forces are exerted on circular cylinders with moderately large blockages (d/h = 0.2 to 0.33) at high Reynolds numbers (3.5 × 105 – 1.2 × 106). The results show that, within the range studied, the gap flow velocity is the correct flow velocity to compensate for wall interference effects. The data reported here represent the first available information on experimental cross-flow-induced forces at such high Reynolds numbers using water as a flow medium.
The Nonlinear Dynamic Analysis of Shells of Revolution With Asymmetric Properties by the Finite Element Method
Authors: Klein S.
Published: November 2010

A large deflection elastic-plastic analysis for general structures by the finite element method is presented. A Von Mises yield condition, its associated flow rule, and isotropic hardening are assumed. Nonlinear forces, due to nonlinear strain-displacement relations, plastic strains, and thermal gradients are developed for static and dynamic analyses and specialized for shell of revolution finite elements with asymmetric properties. The nonlinear dynamic equations are converted to a linear finite difference matrix equation, based on a nonlinear form of the Newmark Beta time integration method. A computer program, SABOR/DRASTIC 6, is used to demonstrate static, dynamic, and dynamic buckling solutions containing large deflection elastic-plastic response of shells with asymmetric properties and loads.
Constitutive Equations for Tensile and Creep Behavior of a 9 Cr-1 MO Steel
Authors: Ellis F. V. , Bynum J. E. , Roberts B. W.
Published: November 2010

This paper describes an investigation of the tensile and creep properties of annealed 9 Cr-1 Mo steel. Tensile tests were conducted at temperatures from 70 to 1050 F while creep tests were conducted at 750, 850, 950, and 1050 F with stresses from 4 to 52 ksi. From the tensile test data, a constitutive equation was developed for the stress-plastic strain relationship. This equation was based on a two-stage hardening mechanism and combined power law and exponential functions. From the creep test data, isochronous stress-strain curves were constructed out to 104 hr. These curves were extrapolated to 105 hr and to lower stresses using a parametric analysis procedure. Additionally, a creep constitutive equation capable of describing the total creep curve, including the tertiary region, was developed. This equation, having three stress and temperature dependent parameters predicted creep curves which were in good agreement with the actual curves. Both the time-independent (tensile) and time-dependent (creep) constitutive equations are suitable for use in finite element stress analysis computer programs.
Creep Bending Tests of Large Weld Overlay and Base Metal Specimens at 1000°F (537.7°C)
Authors: Berman I. , Henschel R.
Published: November 2010

One thousand-hr beam bending creep tests at 1000° F (537.7° C) on four, one-in. (25.4-mm) deep stainless steel specimens of seven-in. gage length with constant end moment were run. The specimens included: two of all weld metal, one of base metal and one bimetallic beam. The short time and creep bending results are compared to the results of a finite element analysis in which book values are used. The experimental results indicate some significant differences in short time properties and primary creep. The analytical results substantially underestimate the primary creep.
Strength of Reinforced Concrete Chambers Under External Pressure
Authors: Buyukozturk O. , Marcal P. V.
Published: November 2010

A study was made to establish the strength of concrete chambers subjected to external pressure with special reference to the reinforced concrete cylindrical tanks. The finite element method as implemented in a nonlinear general purpose program produced analytical results which agreed with the experiment. The study concluded that the cylindrical tank was weakened in buckling by 20 percent due to geometric imperfection, 10 percent due to creep and 6 percent due to reinforcements. The main failure mode of the shell was compression shear.
Stability of Internally Pressurized Vessels With Ellipsoidal Heads
Authors: Brown K. W. , Kraus H.
Published: November 2010

Cylindrical vessels with 2:1 ellipsoidal heads in the range of radius to thickness ratios from 200 to 5000 were analyzed with a finite element program to determine the internal pressures that would cause circumferential wrinkling (buckling). The vessels and heads were taken to be of equal thickness and linear work hardening was assumed wherever appropriate. The buckling pressures were obtained by the adjacent equilibrium method; thus, post-buckling behavior was not considered. Comparisons to other contemporary analyses and experimental data were also made.
Creep Behavior of SMA Type 316 Weld Metal With Controlled Residual Elements
Authors: King R. T. , Cole N. C. , Goodwin G. M.
Published: November 2010

Type 316 stainless steel filler metal is a candidate material for welds in piping and other components of Liquid Metal Fast Breeder Reactors. There are few elevated-temperature tensile and creep data for type 316 weld metal in the literature, and reported properties vary widely with material batches or welding process variables. A nuclear components fabricator has developed a type 316 SMA weld that contains controlled amounts of the residual elements (CRE) boron, phosphorus, and titanium, analogous to the chemical element content of an improved type 308 CRE weld that was reported recently. The type 316 CRE weld has good strength and ductility at 649°C in both short-term tensile tests and creep tests lasting up to about 6000 hr. No tendency for cracking along interphase boundaries or substructural boundaries was found in these limited tests.
An Introduction to Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code
Authors: Moore C. V.
Published: November 2010

A general introduction to Section VIII, Division 1, primarily from the viewpoint of the designer, is presented. The organization of the different sections of the Code are explained, and the requirements of the various Subsections of the Code are outlined—stressing those portions which are frequently misinterpreted or subject to dispute.
Improved 2 1/4 Cr-1 Mo Pressure Vessel Steel Through Electroslag Remelting
Authors: Gulya J. A. , Swift R. A.
Published: November 2010

Results of a detailed investigation of the internal quality and mechanical properties of electroslag remelted 2 1/4 percent Cr-1 percent Mo steel are presented. Superiority over air melted-vacuum degassed electric furnace product in terms of homogeneity and cleanliness is evident. This quality enhancement is reflected by significant increases in ductility-dependent mechanical properties, and minimal anisotropy. Overall plate quality was established by straight-beam ultrasonic testing 100 percent of the volume to strict flat-bottom hole standards. Quality was further evaluated in critical locations by means of extensive chemical analysis, macro-etch tests, sulfur prints, and inclusion ratings. Comparison of results from various locations within the plate and gage demonstrated the advanced degree of uniformity and cleanliness. Mechanical property data exhibited improvements in toughness and tensile properties in all conditions—annealed, normalized and tempered, quenched and tempered. For example, exceptionally high CVN upper shelf energies are shown by quenched and tempered plate at three strength levels. Mechanical isotropy is greatly increased by electroslag remelting, particularly in the through-gage direction. Other improvements noted are superior fracture toughness as measured by KIc, resistance to slow crack growth (da/dN), and resistance to bending fatigue.
An Evaluation of the Material Capabilities of Low Carbon 2 1/4 Cr-1 Mo Steel Forgings
Authors: Fetterolf F. P. , Hurtt J. H.
Published: November 2010

Recent advances in the nuclear power generation field have pointed out the need for ferritic steels which will maintain properties at high operating temperatures for extended periods of time. Present designs for the Clinch River Breeder Reactor Project (CRBRP) specify the use of low carbon 2 1/4 Cr - 1 Mo steel for the Steam Generation systems. Many materials development programs have concluded the acceptability of this material; however, little industrial data are available on the mechanical properties of full size production components. This paper evaluates two heats of low carbon 2 1/4 Cr-1 Mo steel subjected to various heat treatments.
Three-Dimensional Versus Axisymmetric Finite-Element Analysis of a Cylindrical Vessel Inlet Nozzle Subject to Internal Pressure—A Comparative Study
Authors: Truitt J. B. , Raju P. P.
Published: November 2010

This paper presents a comparative study between a three-dimensional and an axisymmetric finite-element analysis of a reactor pressure-vessel inlet nozzle subject to internal pressure. A quarter-symmetric section of the nozzle is modeled with a three-dimensional quadratic isoparametric finite element. This comparative study proves that the axisymmetric analysis is unconservative if based upon common axisymmetric modeling techniques. This inadequacy, for the PWR vessel inlet nozzle studied herein, can be offset by a modification of the modeling techniques, i.e., if the value of the radius of the equivalent spherical vessel is taken as 3.2 instead of, say, 2. The results of the three-dimensional finite-element analysis are also compared with those of a photo-elastic stress analysis and with the stress indices indicated by the ASME Section III Code. These additional comparisons, based upon a continuous distribution of hoop and tangential stress indices in both the transverse and longitudinal planes, shows good agreement between the three-dimensional finite-element and photoelastic analyses. The ASME Section III stress indices are found to be relatively conservative.
Vibratory Power Delivery to Rock During Rotary-Vibratory Drilling
Authors: Ohanehi D. C. , Mitchell L. D.
Published: November 2010

This paper outlines the theoretical description of the vibratory portion of the rotary-vibratory drilling process. A multiple mechanical element model is used to describe the drill string and rock-rock bit assembly. The drill string model has continuously distributed properties of mass, stiffness, and external drilling-mud damping. A closed form solution is developed using boundary condition matching at the end of each mechanical element. The solution is used to compute the power input to the system by a vibratory unit, the power delivered to the rock, and the power lost to the drilling mud through vibratory losses. From these data, efficiencies are computed. The analytical solution has been checked in parallel with a transfer matrix computer solution. The results are identical within computer precision. The analytical model is then applied to the study of the Drilling Research Incorporated (DRI) prototype drilling system and its test drilling parameters for the 1957 test drilling. Explanations of the limits of the increase in drilling rates to 2:1 are explored. The results are explored relative to the potential for increasing the drill penetration rates by system redesign. Conclusions are drawn concerning the most productive routes to be taken for rotary-vibratory drilling systems and for the vibratory driver. It has become clear that successful future downhole rotary-vibratory drilling rigs will require a complete system understanding, a complete system design, and a new concept in vibratory driver.
Drag on a Group of Cylinders
Authors: Dalton C. , Szabo J. M.
Published: November 2010

An experimental investigation of the effects of spacing, orientation and Reynolds number on the drag of each cylinder in a group of two and three cylinders was carried out. The drag forces were measured by means of strain gages. The results indicate that the drag is strongly affected by mutual interaction with neighboring cylinders over a range of separation distances and angles of orientation with respect to the free-stream flow. The interaction decreases with increasing orientation angle, becoming very weak at θ = 90 deg when the cylinders are separated by at least two diameters. For spacings of approximately four diameters, the drag coefficients for the three-cylinder geometry reach a value which will remain almost constant for larger spacings. This is true for all three cylinders and for all orientations. The orientation of the cylinders influences only slightly the drag on the upstream cylinder for groups of both two and three cylinders. For downstream cylinders, the drag coefficient decreases with increasing Reynolds number due to the increased amount of unsteadiness contained in the flow behind the upstream cylinder.
The Mechanical Properties of the Pittsburgh Coal at Elevated Temperatures
Authors: Shoemaker H. D. , Shuck L. Z. , Haynes R. R. , Advani S. H.
Published: November 2010

Mechanical properties of coal have been determined in an effort to advance in situ coal gasification technology. Tests and apparatus were developed to evaluate the directional compressive and shear properties of coal at elevated temperatures. Both creep and stress-relaxation experiments were conducted to evaluate the creep compliance and stress-relaxation properties in compression and shear, at temperatures between 75° and 650°F (24° and 343°C), for the face cleat, butt cleat and normal to coalbed orientation, and four different specimen sizes. Stress-strain relations and ultimate strengths were also determined at three different loading rates for these directions and temperatures. A shift function was used to represent the creep and stress relaxation properties as functions of time and temperature. Four- and six-parameter viscoelastic fluid models were used to represent the data over the time-temperature ranges. Shallow and deep mine coal from the Pittsburgh coalbed was tested. The coal was found to have the greatest ultimate strength and elastic moduli at 200°F (93°C) in all directions in both compression and shear, and to be specimen size dependent. The ultimate strength in the normal to coalbed direction was approximately twice that in the face and butt cleat directions at all temperatures. At 575° to 650°F (302° – 343°C), the coal becomes fluidic and is well represented by a four-parameter fluid model. It also obeys the time-temperature superposition principle.
Crack Propagation and Arrest in Pressurized Containers
Authors: Erdogan F. , Delale F. , Owczarek J. A.
Published: November 2010

The problem of crack propagation and arrest in a finite volume cylindrical container filled with pressurized gas is considered. It is assumed that the cylinder contains a symmetrically located longitudinal part-through crack with a relatively small net ligament. The net ligament suddenly ruptures initiating the process of fracture propagation and depressurization in the cylinder. Thus the problem is a coupled gas dynamics and solid mechanics problem the exact formulation of which does not seem to be possible. It is formulated by making two major assumptions, namely that the shell problem is quasi-static and the gas dynamics problem is one-dimensional. The problem is reduced to a proper initial value problem by introducing a dynamic fracture criterion which relates the crack acceleration to the difference between a load factor and the corresponding strength parameter. The main results are demonstrated by considering two examples, an aluminum cylinder which may behave in a quasi-brittle manner, and a steel cylinder which undergoes ductile fracture. The results indicate that generally in gas-filled cylinders fracture arrest is not possible unless the material behaves in a ductile manner and the container is relatively long.
Flexibility and Stress Factors of Pipe Bends—An Analysis by the Finite Ring Method
Authors: Ohtsubo H. , Watanabe O.
Published: November 2010

The present paper investigates the flexibility and stress factors for the pipe bends when they are connected with straight pipes and subjected to out-of-plane as well as in-plane bending moments, to which the conventional methods are not directly applicable. The stress analysis is carried out by the use of a new finite ring element method which is based on the general thin shell theory incorporating shear strain. The numerical results obtained for flexibility and stress factors are compared with the code formula. The influence of initial deflections and the variation of the pipe wall thickness is also studied.
Data-Based Computer System for Pressure Vessel Design
Authors: Zamma J. , Mitsufuji A. , Maruyama S. , Tadano M.
Published: November 2010

The Data-Based Computer System newly developed for the design of pressure vessels has overcome some of the difficulties which were incidental to conventional computer systems. The system fulfills most functions for ordinary type pressure vessels including cost optimization, automated material selection, etc. and meets the requirements of both ASME VIII-1 and Japanese regulations. A combination of a built-in data base and POL (Problem Oriented Language) allows the reduction of the amount of input and promotes effective and easy man-machine communication. Ease of maintenance and capacity for expansion allow prompt adaptation to the up-to-date requirements of the codes and standards.
Dynamic Seismic Analysis of Long Segmented Lifelines
Authors: Nelson I. , Weidlinger P.
Published: November 2010

The difference in ground motion along a lifeline, the incoherent motion, is an essential component of the input. A long, straight, segmented pipe, with each link attached to the ground via a spring and dashpot is subjected to incoherent ground motion caused by a phase delay. The equations governing the axial response of the system are developed. Modal decomposition is used and closed form expressions are given for the natural frequencies and mode shapes. Examples are given showing the center joint displacement time history when the lifeline is subjected to earthquake loading. Spectral techniques can be used to bound the motion with the Interference Response (IR) spectrum. This spectrum is the maximum difference in motion (response) of two adjacent points which are excited by a difference in ground input. It is seen that the IR spectrum is a useful tool in the dynamic analysis of lifelines over a broad range of parameters.
Plastic Collapse and the Controlling Failure Pressures of Thin 2:1 Ellipsoidal Shells Subjected to Internal Pressure
Authors: Galletly G. D. , Aylward R. W.
Published: November 2010

In the first part of the paper, plastic collapse pressures of thin 2:1 ellipsoidal shells are determined. The effects of E, σyp and strain hardening, S, on the collapse pressure are presented and discussed. The second part of the paper is concerned with the controlling failure pressures of internally pressurized 2:1 ellipsoidal shells. This involves the consideration of both plastic collapse pressures and asymmetric buckling pressures (the latter were obtained from a companion paper). Curves of the controlling failure pressures versus D/t are given for several values of σyp and S. Both aluminum and steel shells are considered. Dimensionless buckling and collapse pressures are also tabulated and some very simple formulas for both failure modes are suggested which should be useful to designers.
Stability Design Criterion for Vessels Subjected to Concurrent External Pressure and Longitudinal Compressive Loads
Authors: Gilbert N. , Polani J. R.
Published: November 2010

This paper presents a design procedure for determining the maximum allowable compressive stress and the maximum allowable external pressure for cylindrical vessels subjected to loadings which produce both longitudinal and circumferential stresses simultaneously. Although the ASME Pressure Vessel Code Section VIII [1] mentions the combinations of loadings as a factor in determining the thickness of vessels, the Code procedures (UG-23) for longitudinal compressive stress and (UG-28) for external pressure do not consider the interaction of these two buckling loads when acting concurrently. Calculations of typical vessels subjected to these conditions reveal that adherence to the Code rules without inclusion of these effects may yield results which fall below the safe design limits established by the Code. The design procedure developed herein extends the existing Code formulations as applicable; and incorporates established elastic stability data as necessary.
Consistent Creep and Rupture Properties for Creep-Fatigue Evaluation
Authors: Schultz C. C.
Published: November 2010

The currently accepted practice of using inconsistent representations of creep and rupture behaviors in the prediction of creep-fatigue life is shown to introduce a factor of safety beyond that specified in current ASME Code design rules for 304 stainless steel Class 1 nuclear components. Accurate predictions of creep-fatigue life for uniaxial tests on a given heat of material are obtained by using creep and rupture properties for that same heat of material. The use of a consistent representation of creep and rupture properties for a minimum strength heat is also shown to provide reasonable predictions. The viability of using consistent properties (either actual or those of a minimum strength heat) to predict creep-fatigue life thus identifies significant design uses for the results of characterization tests and improved creep and rupture correlations.
Investigation of Warm Prestress for the Case of Small ΔT During a Reactor Loss-of-Coolant Accident
Authors: Loss F. J. , Gray R. A. , Hawthorne J. R.
Published: November 2010

An experimental investigation was conducted to characterize the benefits of warm prestress (WPS) in limiting crack extension in the wall of a nuclear vessel during a LOCA-ECCS. The present research emphasized material behavior under conditions of a small ΔT between the temperature of WPS and the failure temperature as might occur during a LOCA. The results have demonstrated that fracture will not occur during a simultaneous unloading and cooling of the crack-tip region following WPS even though the critical KIc of the virgin material is achieved. Based on a statistical analysis, it is concluded that WPS produces an “effective” elevation in KIc; furthermore, it is suggested that this elevation will limit crack extension in the vessel wall so as to retain the coolant.
A Three-Dimensional Finite Element Analysis of the Double-Torsion Test
Authors: Tseng A. A. , Berry J. T.
Published: November 2010

A special three-dimensional crack-tip element has been developed to investigate a simple and widely applicable fracture toughness test method. Previous experimental work with the double-torsion method has shown that the use of a relatively thin sectioned specimen may be permitted. The section concerned is considerably thinner than that used in conventional techniques, while the technique also simplifies the determination of the fracture toughness parameter. K IC values, which are independent of the crack length, have been obtained for glasses, ceramics, polymers, and a variety of metals and alloys. The numerical solution presented is supportive of many experimental observations made during testing. Excellent correlation between the finite element and experimental results has been obtained. The maximum stress intensity factor is shown to be almost independent of crack length over a considerable range.
On Immunologists and Microbiologists: Ground Zero in the Battle for Interdisciplinary Knowledge
Authors: Biron Christine A. , Casadevall Arturo
Published: November 2010

The individual disciplines of microbiology and immunology are exploding with new information necessary for understanding host-pathogen relationships, infectious diseases, cancer, and autoimmunity. Because of overlapping scientific interests, immunologists and microbiologists often share common academic affiliations. The coexistence is uneasy. Significant problems arise because the groups have evolved different intellectual traditions. Pressures are intensified by sporadic changes in perceptions of their relative worth. As the mixing of microbiologists and immunologists can be likened to ground zero in the fight for interdisciplinary knowledge, it is useful, at this time of escalating data acquisition and growing appreciation for multidisciplinary research, to examine their histories, the challenges to amalgamation, and the advantages of their association for the advancement of knowledge and the delivery of protection against disease. The exploration supports a recommitment to integration of the disciplines and a proposal to facilitate this by inclusion of expertise bridging the areas.
Differential expression of apoptosis-related genes from death receptor pathway in chronic myeloproliferative diseases
Authors: Tognon Raquel , Gasparotto Elainy Patrícia Lino , Leroy Janine Marie Gisele , Oliveira Gislane Lelis Vilela , Neves Renata Peres , Carrara Rita de Cássia Viu , Kashima Simone , Covas Dimas Tadeu , Santana Mary , Souto Elizabeth Xisto , Zanichelli Maria Aparecida , Velano Carlos Eduardo Engel , Simões Belinda Pinto , Alberto Fernando Lopes , Miyashiro Kozue , de Souza Ana Maria , Amarante-Mendes Gustavo Pessini , de Castro Fabíola Attié
Published: November 2010

Background

Chronic myeloproliferative disorders (MPDs) are clonal haematopoietic stem cell malignancies characterised by an accumulation of mature myeloid cells in bone marrow and peripheral blood. Deregulation of the apoptotic machinery may be associated with MPD physiopathology.

Aims

To evaluate expression of death receptors' family members, mononuclear cell apoptosis resistance, and JAK2 allele burden.

Subjects and Methods

Bone marrow haematopoietic progenitor CD34 cells were separated using the Ficoll-hypaque protocol followed by the Miltenyi CD34 isolation kit, and peripheral blood leukocytes were separated by the Haes-Steril method. Total RNA was extracted by the Trizol method, the High Capacity Kit was used to synthesise cDNA, and real-time PCR was performed using SybrGreen in ABIPrism 7500 equipment. The results of gene expression quantification are given as 2−ΔΔCt. The JAK2 V617F mutation was detected by real-time allelic discrimination PCR assay. Peripheral blood mononuclear cells (PBMCs) were isolated by the Ficoll-hypaque protocol and cultured in the presence of apoptosis inducers.

Results

In CD34 cells, there was mRNA overexpression forfas,faimandc-flipin polycythaemia vera (PV), essential thrombocythaemia (ET) and primary myelofibrosis (PMF), as well asfaslin PMF, anddr4levels were increased in ET. In leukocytes,fas,c-flipandtraillevels were increased in PV, anddr5expression was decreased in ET. There was an association betweendr5andfaslexpression and JAK2V617F mutation. PBMCs from patients with PV, ET or PMF showed resistance to apoptosis inducers.

Conclusions

The results indicate deregulation of apoptosis gene expression, which may be associated with MPD pathogenesis leading to accumulation of myeloid cells in MPDs.
Factors influencing the relative fitness of hatchery and wild spring Chinook salmon (Oncorhynchus tshawytscha) in the Wenatchee River, Washington, USA
Authors: Williamson Kevin S. , Murdoch Andrew R. , Pearsons Todd N. , Ward Eric J. , Ford Michael J.
Published: November 2010

Understanding the relative fitness of naturally spawning hatchery fish compared with wild fish has become an important issue in the management and conservation of salmonids. We used a DNA-based parentage analysis to measure the relative reproductive success of hatchery- and natural-origin spring Chinook salmon ( Oncorhynchus tshawytscha ) in the natural environment. Size and age had a large influence on male fitness, with larger and older males producing more offspring than smaller or younger individuals. Size had a significant effect on female fitness, but the effect was smaller than on male fitness. For both sexes, run time had a smaller but still significant effect on fitness, with earlier returning fish favored. Spawning location within the river had a significant effect on fitness for both sexes. Hatchery-origin fish produced about half the juvenile progeny per parent when spawning naturally than did natural-origin fish. Hatchery fish tended to be younger and return to lower areas of the watershed than wild fish, which explained some of their lower fitness.
Re-assessment of the stock–recruit and temperature–recruit relationships for Pacific sardine (Sardinops sagax)
Authors: McClatchie Sam , Goericke Ralf , Auad Guillermo , Hill Kevin
Published: November 2010

The harvest guideline for Pacific sardine ( Sardinops sagax ) incorporates an environmental parameter based on averaged surface temperatures at the Scripps Institution of Oceanography pier (SIO pier) in La Jolla, California, USA, which would be invoked after a series of cool years to reduce commercial catches using a precautionary decision rule. We revisit the stock–recruit and temperature–recruit relationships underpinning the currently used environmental parameter for sardine assessment and found that the temperature–recruit relationship no longer holds for the SIO pier when time series are updated with data from more recent years. The significance of the correlation between temperature and recruitment was also artificially increased by autocorrelation in the time series. In contrast, the stock–recruit relationship was still valid when recent data were added. SIO pier surface temperatures are warmer than 10 m-depth Southern California Bight (SCB) temperatures where the sardine spawn, and the difference has increased since the late 1970s. Sardine recruitment was also not related to offshore temperatures in the SCB. We demonstrate that the environmental proxy derived from SIO pier temperature, which has never affected the harvest guideline since its implementation, no longer predicts recruitment of Pacific sardine, and should be removed from sardine management.
Modeling individual conifer seed shape as a sum of fused partial ellipsoids
Authors: Keefe Robert F. , Davis Anthony S.
Published: November 2010

Because of the importance of seed surface area, volume, and fill to hydraulic and thermal exchanges with the soil, mechanistic simulation of seed physiological processes associated with tree migration dynamics and the spread of invasive species require accurate equations to model seed shape. Seed dimensions have previously been described with measurements of the three principal axes, assuming an implied single ellipsoid. However, conifer seeds often exhibit anisotropy that results from bilaterally symmetric pairing on cone scales. We developed a method for measuring and modeling conifer seed shape as a sum of 2jpartial ellipsoids fused at their equators, where j = 0, …, 3. We demonstrate the use of the methods in the study of shape characteristics of ponderosa pine (Pinus ponderosa P.& C. Lawson) seeds from four families in Montana and among commercial lots of ponderosa pine, lodgepole pine (Pinus contorta Dougl. ex Loud.), and Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco). The shapes of 92%, 73%, and 47% of seeds in commercial lots studied had eight unique ellipsoids when classified with 1%, 5%, and 10% difference classification rules, respectively. Ponderosa pine seeds with longer minor axes were less well filled with storage reserves. Three-dimensional surface areas of lodgepole and ponderosa pine were approximately 2 and 3.4 times larger, respectively, than previously reported one-sided surface areas.
MOMENTS OF SPIN STRUCTURE FUNCTIONS: SUM RULES AND POLARIZABILITIES
Authors: CHEN J.-P.
Published: November 2010

Nucleon structure study is one of the most important research areas in modern physics and has challenged us for decades. Spin has played an essential role and often brought surprises and puzzles to the investigation of the nucleon structure and the strong interaction. New experimental data on nucleon spin structure at low to intermediate momentum transfers combined with existing high momentum transfer data offer a comprehensive picture in the strong region of the interaction and of the transition region from the strong to the asymptotic-free region. Insight into some aspects of the theory for the strong interaction, Quantum Chromodynamics (QCD), is gained by exploring lower moments of spin structure functions and their corresponding sum rules (i.e., the Bjorken, Burkhardt–Cottingham, Gerasimov–Drell–Hearn (GDH), and the generalized GDH). These moments are expressed in terms of an operator-product expansion using quark and gluon degrees of freedom at moderately large momentum transfers. The higher-twist contributions have been examined through the evolution of these moments as the momentum transfer varies from higher to lower values. Furthermore, QCD-inspired low-energy effective theories, which explicitly include chiral symmetry breaking, are tested at low momentum transfers. The validity of these theories is further examined as the momentum transfer increases to moderate values. It is found that chiral perturbation theory calculations agree reasonably well with the first moment of the spin structure function g1 at low momentum transfer of 0.05–0.1 GeV2 but fail to reproduce some of the higher moments, noticeably, the neutron data in the case of the generalized polarizability δLT. The Burkhardt–Cottingham sum rule has been verified with good accuracy in a wide range of Q2 assuming that no singular behavior of the structure functions is present at very high excitation energies.
LESS-INVASIVE LASER THERAPY AND DIAGNOSIS USING A TABLETOP MID-INFRARED TUNABLE LASER
Authors: HAZAMA HISANAO , ISHII KATSUNORI , AWAZU KUNIO
Published: November 2010

Since numerous characteristic absorption lines caused by molecular vibration exist in the mid-infrared (MIR) wavelength region, selective excitation or selective dissociation of molecules is possible by tuning the laser wavelength to the characteristic absorption lines of target molecules. By applying this feature to the medical fields, less-invasive treatment and non-destructive diagnosis with absorption spectroscopy are possible using tunable MIR lasers. A high-energy nanosecond pulsed MIR tunable laser was obtained with difference-frequency generation (DFG) between a Nd:YAG and a tunable Cr:forsterite lasers. The MIR-DFG laser was tunable in a wavelength range of 5.5–10 μm and generated laser pulses with energy of up to 1.4 mJ, a pulse width of 5 ns, and a pulse repetition rate of 10 Hz. Selective removal of atherosclerotic lesion was successfully demonstrated with the MIR-DFG laser tuned at a wavelength of 5.75 μm, which corresponds to the characteristic absorption of the ester bond in cholesterol esters in the atherosclerotic lesions. We have developed a non-destructive diagnostic probe with an attenuated total reflection (ATR) prism and two hollow optical fibers. An absorption spectrum of cholesterol was measured with the ATR probe by scanning the wavelength of the MIR-DFG laser, and the spectrum was in good agreement with that measured with a commercial Fourier transform infrared spectrometer.
RETINAL SPECTRAL IMAGING AND BLOOD FLOW MEASUREMENT
Authors: LEMAILLET PAUL , DUNCAN DONALD D. , LOMPADO ART , IBRAHIM MOHAMED , NGUYEN QUAN DONG , RAMELLA-ROMAN JESSICA C.
Published: November 2010

Measurement of both oxygen saturation and blood flow in the retinal vessels has proved to give important information about the eye health and the onset of eye pathologies such as diabetic retinopathy. In this study, we present the implementation, on a commercially available fundus camera, of a retinal imager and a retina blood flow velocimeter. The retinal imager uses division of aperture to acquire nine wavelength-dependent sub-images of the retina. Careful consideration is taken to improve image transfer by measuring the optical properties of the fundus camera and modeling the optical train in Zemax. This part of the setup is calibrated with optical phantoms of known optical properties that are also used to build a lookup table (LUT) linking phantom optical properties to measured reflectance. The retina blood flow velocimeter relies on tracking clusters of erythrocytes and uses a fast acquisition camera attached to a zoom lens, with a green illumination LED-engine. Calibration is provided using a calibrated quartz capillary tube and human blood at a known flow rate. Optical properties of liquid phantoms are retrieved from measured reflectance using the LUT, and blood flow measurements in the retina are presented.
A DIFFUSION–TRANSPORT HYBRID METHOD FOR ACCELERATING OPTICAL TOMOGRAPHY
Authors: KIM HYUN KEOL , HIELSCHER ANDREAS H.
Published: November 2010

It is well acknowledged that the equation of radiative transfer (ERT) provides an accurate prediction of light propagation in biological tissues, while the diffusion approximation (DA) is of limited accuracy for the transport regime. However, ERT-based reconstruction codes require much longer computation times as compared to DA-based reconstruction codes. We introduce here a computationally efficient algorithm, called a diffusion–transport hybrid solver, that makes use of the DA- or low-order ERT-based inverse solution as an initial guess for the full ERT-based reconstruction solution. To evaluate the performance of this hybrid method, we present extensive studies involving numerical tissue phantoms and experimental data. As a result, we show that the hybrid method reduces the reconstruction time by a factor of up to 23, depending on the physical character of the problem.
On (Omega-)regular model checking
Authors: Legay Axel , Wolper Pierre
Published: November 2010

Checking infinite-state systems is frequently done by encoding infinite sets of states as regular languages. Computing such a regular representation of, say, the set of reachable states of a system requires acceleration techniques that can finitely compute the effect of an unbounded number of transitions. Among the acceleration techniques that have been proposed, one finds both specific and generic techniques. Specific techniques exploit the particular type of system being analyzed, for example, a system manipulating queues or integers, whereas generic techniques only assume that the transition relation is represented by a finite-state transducer, which has to be iterated. In this article, we investigate the possibility of using generic techniques in cases where only specific techniques have been exploited so far. Finding that existing generic techniques are often not applicable in cases easily handled by specific techniques, we have developed a new approach to iterating transducers. This new approach builds on earlier work, but exploits a number of new conceptual and algorithmic ideas, often induced with the help of experiments, that give it a broad scope, as well as good performances.
Extrusion and revolution mapping
Authors: Halli Akram , Saaidi Abderrahim , Satori Khalid , Tairi Hamid
Published: November 2010

Extrusion, bevel, chamfer, and lathe tools are widely used in a large variety of computer graphics applications such as architectural designs and industrial prototyping of manufactured goods. However, such modeling is usually based on polygonal meshes which often require a considerable amount of graphics primitives. In this article, we present a new image-based approach for rendering extruded and revolved surfaces. We use only a single RGBA texture which stores a binary map (i.e. The profile curve), its Euclidean distance transform, and the two components of the unit gradient vector of the distance fields. All rendering algorithms are based on a ray-tracing procedure performed in texture space. The use of the distance fields allows culling of empty space and thus minimizes the number of ray-tracing steps. The extrusion and revolution mapping techniques produce very convincing models, and both are rendered at interactive frame rates.
A PML-based nonreflective boundary for free surface fluid animation
Authors: Söderström Andreas , Karlsson Matts , Museth Ken
Published: November 2010

This article presents a novel nonreflective boundary condition for the free surface incompressible Euler and Navier-Stokes equations. Boundaries of this type are very useful when, for example, simulating water flow around a ship moving over a wide ocean. Normally waves generated by the ship will reflect off of the boundaries of the simulation domain and as these reflected waves return towards the ship they will cause undesired interference patterns. By employing a Perfectly Matched Layer (PML) approach we have derived a boundary condition that absorbs incoming waves and thus efficiently prevents these undesired wave reflections. To solve the resulting boundary equations we present a fast and stable algorithm based on the stable fluids approach. Through numerical experiments we then show that our boundaries are significantly more effective than simpler reflection preventing techniques. We also provide a thorough analysis of the parameters involved in our boundary formulation and show how they effect wave absorption efficiency.