bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Steam-Turbine Reheat on Speed-Governor Performance
Authors: Concordia Charles
Published: May 2019

This paper shows the effect on the frequency stability and response of an electric power system of the use of steam-turbine reheat. It is shown that in general reheat tends to decrease the damping of the frequency variations of the system as a whole, to increase the damping of tie-line power oscillations, and to increase the maximum frequency deviation occasioned by an abrupt load change. The system responses were determined by means of an analog computer.
Turbine Cooling
Authors: Esgar Jack B.
Published: May 2019

Turbine cooling, originally developed because of a shortage of heat-resistant alloys, is of interest for certain applications to permit operation of gas-turbine engines above uncooled temperatures. Specific power output would be increased, and in some cases specific fuel consumption decreased, depending on the engine type. Progress is reported on developments since 1952.
Nuclear
Authors: Godwin Richard P. , Dennison Edward S.
Published: May 2019

The nuclear gas-turbine plant has recently become the basis for a substantial development program. Because of considerable difficulties, particularly in the areas of heat and radiation-resistant materials, from 5 to 7 years must elapse before any real accomplishment can be demonstrated. The most attractive line of development from a cost, efficiency, and weight point of view, appears to be the single-fluid gas system, discussed in detail. The case for the optimum gas is not clear-cut. Thermodynamic, system, and bearing and seal problems are considered.
The Transient Response of Gas-Turbine-Plant Heat Exchangers—Regenerators, Intercoolers, Precoolers, and Ducting
Authors: London A. L. , Biancardi F. R. , Mitchell J. W.
Published: May 2019

This is the second report of a program dealing with the transient response of heat exchangers [1a], [1b]. Analog solutions are used to supplement some analytical solutions so as to provide fairly complete coverage for the heat exchangers encountered in gas-turbine plants. Because a gas flow exists on at least one side of the heat-transfer surface, these exchangers are characterized by a large wall-capacitance effect. Where greater generality is possible, the extension to other heat exchangers is indicated.
Stresses in Hollow Cylinders Due to Asymmetrical Heat Generation
Authors: Kraus Harry , Sonnemann George
Published: May 2019

Equations are derived for the radial, tangential, shear, and axial stresses arising in nuclear reactor vessels, thermal shields, and so on, from internal heat generation caused by the absorption of gamma radiation. The heat generation considered behaves as a decaying exponential through the wall of the hollow cylinder and is an arbitrary function of the angle around the axis of the cylinder.
Transient Heat Transfer for Laminar Forced Convection in the Thermal Entrance Region of Flat Ducts
Authors: Siegel R. , Sparrow E. M.
Published: May 2019

An analysis is made for transient laminar heat transfer in the thermal entrance region of a flat duct (parallel plate channel) whose bounding surfaces are subjected to an arbitrary time variation of temperature or of heat flux. Initially, the system may be either in an already established steady-state heat-transfer situation, or else, the fluid and duct walls may be at the same uniform temperature. The velocity distribution in the flow is taken to be fully developed and unchanging with time. The solution for arbitrary time-dependent conditions is obtained by generalizing the thermal response to a unit step change in wall temperature or in wall heat flux. This step-function response is found by using the method of characteristics. Heat-transfer results are presented as simple analytical expressions. The time required to achieve steady state after a unit step is also given. Working formulas are summarized at the end of the paper.
Numerical and Machine Solutions of Transient Heat-Conduction Problems Involving Melting or Freezing: Part I—Method of Analysis and Sample Solutions
Authors: Murray William D. , Landis Fred
Published: May 2019

Previously published methods for the solution of one-dimensional heat-conduction problems with melting or freezing are briefly reviewed and weaknesses of previous analytic and numerical methods are outlined. Two new and more generally applicable numerical methods, applicable to digital and analog computation, are developed in the paper. Sample problems using these new techniques are solved and compared with the results of a widely used conventional method. An evaluation of the various methods and recommendations on areas of application are included.
Laminar Heat Transfer in Rectangular Channels
Authors: Han L. S.
Published: May 2019

Three cases of laminar heat transfer with linear heat input in long rectangular channels have been treated by the method of orthogonal trigonometric series. The boundary conditions of the first two problems are those of laminar and slug flows with two opposite faces as secondary extended surfaces. A new fin parameter K defined as (wkm/bkf) has been shown to be the important factor in governing the Nusselt number. The third case discussed is the combined effects of free and forced-convection in vertical rectangular tubes.
Heat Transfer From an Annular Fin of Constant Thickness
Authors: Keller H. H. , Somers E. V.
Published: May 2019

The two-dimensional solution for annular fins, given in graphical form with the efficiency plotted versus the design-parameter group, (b − a)[(2h)/(kw)]1/2, supplies needed design information for fins of small height-to-thickness ratio and large height-to-inner radius ratio. The one-dimensional solutions previously given for annular fins are accurate for height-to-width ratios of the order of 10 or more, while the two-dimensional results for rectangular fins are useful as approximations to annular fins when curvature is not large. With height-to-width ratios less than 10 and for annular fins with large curvature, design of fins can be computed with the results presented in this paper.
A Variational Method for Fully Developed Laminar Heat Transfer in Ducts
Authors: Sparrow E. M. , Siegel R.
Published: May 2019

A variational method is presented for determining fully developed velocity and temperature distributions for laminar flow in noncircular ducts. The heat addition to the fluid is taken to be uniform in the axial direction, but a variety of thermal boundary conditions are considered around the periphery of the duct cross section. Several illustrative examples are given, and comparisons are made which show good agreement with available exact solutions. These examples include ducts of rectangular and circular-sector cross sections.
Heating and Cooling Air and Carbon Dioxide in the Thermal Entrance Region of a Circular Duct With Large Gas to Wall Temperature Differences
Authors: Wolf Helmut
Published: May 2019

The local heat-transfer characteristics for air and carbon dioxide in the thermal entrance region have been determined experimentally and are compared with predicted values computed from an extension of the theoretical analysis due to Deissler. The experiments were conducted in smooth round tubes having a fully developed turbulent velocity profile and a uniform temperature distribution at the entrance. The boundary conditions of uniform heat flux for heating the gas, and wall temperature constant and variable with axial distance for cooling the gas, were investigated with large temperature differences between the gas and the tube wall. For heating, the experimental results yielded one per cent thermal entrance lengths ranging from 11 to 27 diameters over the bulk Reynolds number range from 50,000 to 246,000. For cooling, one per cent thermal entrance lengths ranging from 12 to 26 diameters were obtained for bulk Reynolds numbers ranging from 17,000 to 218,000. The agreement between theory and experiment was favorable in most cases.
Laminar Condensation Heat Transfer on a Horizontal Cylinder
Authors: Sparrow E. M. , Gregg J. L.
Published: May 2019

A boundary-layer analysis is made for laminar film condensation on a horizontal cylinder. The formulation includes both the inertia forces and energy convection terms, which are neglected in Nusselt’s simple theory. A similarity transformation, valid over most of the cylinder, is found which reduces the partial differential equations of the problem (the conservation laws) to ordinary differential equations. Numerical solutions of the resulting ordinary differential equations are available for the Prandtl number range from 0.003 to 100. Heat-transfer results are presented and discussed.
Thermodynamic Properties of Helium at Low Temperatures and High Pressures
Authors: Mann D. B. , Stewart R. B.
Published: May 2019

The thermodynamic properties of helium have been compiled and correlated for a temperature range from 3.0 to 20° K for pressures to 100 atmospheres and for specific volumes from 5 to 800 liters per kilogram. The properties are presented on both the temperature-entropy and the enthalpy-entropy co-ordinate systems and include pressure, temperature, volume, entropy, and enthalpy.
Helical Springs of Hollow Circular Cross Section
Authors: Bert C. W.
Published: May 2019

A theoretical and experimental investigation of elastic shear stresses and deflection in an axially loaded helical spring having a hollow circular section is reported in this paper. Two analyses are presented: An approximation of the stresses by strength-of-materials theory and a more accurate elasticity-theory solution for stresses and deflection. The results are compared with strain and deflection measurements on an actual tubular spring.
Vibrations of Flexible Precision Grinding Spindles
Authors: Hahn R. S.
Published: May 2019

The effects of pulsating forces between grinding wheel and workpiece are discussed in connection with inhomogeneous wheel wear and loading. By analysis it is shown that pulsating normal forces may be caused by rotary damping and gyroscopic effects. The influence of skew-symmetric rigidity in the spindle is also discussed and the occurrence of subharmonic resonances is pointed out.
Some Observations on the Shearing Process in Metal Cutting
Authors: Kobayashi S. , Thomsen E. G.
Published: May 2019

It was found that shearing forces on the shear plane were linear functions of the area on which they acted. This was observed for all materials investigated; for SAE 1112 steel, 2024-T4, and 6061-T6 aluminum alloys, and alpha-brass, and also is in agreement with data taken from the literature. Furthermore, all data examined showed that the straight line of shear force Fs versus area As intercepted the ordinate at a positive force value. This was interpreted to mean that the intercept part of the shearing force was used up in overcoming workpiece deformation or friction at the flank of the tool and was not available for chip deformation. Accepting this concept, it can then be shown that the average shearing stress on the shear plane for SAE 1112 is constant and is independent of normal stress, cutting speed, or strain rate, extent of deformation or finite strain, and extent of prior deformation. The shearing stresses for the other materials tested or examined were also constant for the limited range of variables available.

In contrast to the shearing stress, the normal stress on the shear plane was not constant and appears to be a yet unknown function of the mechanism of friction on the tool face.

The shearing stresses calculated from the metal-cutting data showed good correlation with flow stresses at the same finite strains which were obtained from static compression tests. The reason for the uniqueness of the finite strains at which correlation is achieved is not as yet clear.
An Analysis of Critical Stresses and Mode of Failure of a Wire Rope
Authors: Starkey W. L. , Cress H. A.
Published: May 2019

Many wire-rope manufacturers and machine designers are under the impression that the significant stress in a wire rope is the tensile stress, or possibly the stress due to tension and bending. This paper proves by mathematical analysis that by far the greatest stress in a wire rope results from Hertz contact stresses at points of contact of wire-on-wire, and asserts that the usual mode of failure of a wire rope is fretting-fatigue initiated at such points of contact. Design relationships based on these concepts should be of great value to designers who use wire rope.
The Dynamic Analysis and Design of Relatively Flexible Cam Mechanisms Having More Than One Degree of Freedom
Authors: Johnson R. C.
Published: May 2019

The author presents a simple numerical method for analyzing and designing cam systems which have more than one degree of freedom. Illustrative examples are given for follower systems having two degrees of freedom. In addition to the general analysis and design methods which are derived, the examples also illustrate the importance of significant figures in the calculating procedure and the importance of the consideration of the distribution of mass throughout elastic regions. The general method of analysis and design can be extended to follower systems having more degrees of freedom than two.
Influence of Hot and Cold Storage-Loads on the Refrigerated-Space Temperature of a Cooling Complex
Authors: Kayan Carl F.
Published: May 2019

Of particular interest in cold-storage warehouse operations is the influence on the space-temperature-time history of a “hot” load of goods suddenly introduced into the refrigerated zone of an insulated structure. The zone may be completely empty, or partially occupied by warehouse goods already down in temperature. Of further interest is the ultimate effect of the transient load on the performance of other components of the system, such as the connected space-cooling heat exchanger. In previous work in this realm by the author on the behavior of the over-all complex, the studies have included the various heat-exchange and machine energy-transport equipments of the system [1]. Whereas in the earlier paper the transient effect was explored via calculation methods, in the study of the problem in this paper experimental simulation methods are employed entirely, using pilot process-prototype transient-elements.
Ball Motion and Sliding Friction in Ball Bearings
Authors: Jones A. B.
Published: May 2019

In modern high-speed ball bearings the pressure areas, which result from elastic deformations at the ball-race contacts, are appreciably curved and interfacial slip can occur at most points within the pressure areas. These slippages give rise to friction forces acting on the ball which are held in equilibrium by reactions from the races and the inertia effects of the motion of the ball.

A method is derived for determining the motion of the ball and sliding friction in a high-speed, angular-contact ball bearing under thrust load in terms of the inertia effects on the ball and the frictional resistances resulting from interfacial slip at the contact areas. Possible elastic compliance at the interface, hysteresis, and dynamical perturbations of ball motion are neglected. The solution of eight, simultaneous equations involving double integrals for which closed-form solutions cannot be found is required. A solution for a particular case requires the services of a high-speed computer.

For the case where gyroscopic effects on the ball can be neglected, certain simplifications and assumptions can be made which enable the solution of a particular problem using conventional computation means.
Prediction of Choking Flow in Centrifugal Impellers
Authors: Lown Harold , Wiesner Frank J.
Published: May 2019

A method for predicting choking flow in centrifugal impellers is outlined in this paper. The theoretical development of the sonic flow equations for an ideal gas in an impeller passage is combined with empirical data through the derivation of a passage contraction ratio based upon test data. Construction of the three-dimensional passage throat area for two basic types of impellers is also outlined. Good correlation between experimental data and calculated choking flows for other centrifugal impellers is shown by the use of this method. Further utilization of this method for nonideal gases ranging in compressibility from 0.85 to 0.98 seems feasible if small errors can be tolerated.
An Analytic Frequency-Response Solution for a Higher Order Servomechanism With a Nonlinear Control Element
Authors: Hopkin A. M. , Ogata K.
Published: May 2019

On-off-type control systems designed on the basis of step-input response sometimes exhibit poor frequency-response characteristics. When subjected to periodic inputs, such systems may oscillate at subharmonics of the input frequencies under certain conditions. An example of subharmonic response of an on-off-type system is shown in Fig. 1(a). Fig. 1(b) shows the corresponding fundamental response.

When an on-off system is designed with a proportional band, the frequency response of the system must be carefully investigated for the possibility of “jump resonance” and subharmonic oscillations. This is particularly necessary when the system is known to be subjected to occasional periodic inputs.

This paper presents an effective method for evaluating the frequency response, both open-loop and closed-loop, for on-off-type feedback control systems with or without proportional bands. Fig. 2 shows one type of the system under discussion.

The essential material presented follows the Laplace-transform method suggested by D. Kahn [1]. It is an extension of the work already reported by K. Ogata [2, 3].
On the Mechanism of Gear Lubrication
Authors: Borsoff V. N.
Published: May 2019

The paper is a brief review of the research on fundamentals of gear lubrication performed at Shell Development Company for the Bureau of Aeronautics of the Department of the Navy. It is constructed along the following lines: Scoring and wear of gears are evaluated as functions of various operating variables, gear geometry and construction factors, and lubricants properties. This is followed by a brief discussion of the results of experiments performed with tagged extreme pressure lubricants showing distribution and thickness of the extreme pressure films and the rates of their attrition. Based on all of these results, a mechanism of gear lubrication is postulated and discussed.
Friction and Wear of Metals to 1000 C
Authors: Kingsbury E. P. , Rabinowicz E.
Published: May 2019

Sliding experiments using mainly the metals zinc, copper, titanium, and 1020 steel were carried out on a pin-on-disk friction apparatus incorporated in a metallurgical furnace. At room temperatures the results with steel, but not with the other metals, depended markedly on the atmospheric moisture content. As temperatures were raised to 400 C the friction and wear rate of the steel reached a maximum at 100 C and then diminished, while with the other metals the friction remained constant and the wear rate increased. These and other results are discussed in terms of the W/p ratio for the metals, W being the surface energy and p the hardness. It is postulated that materials with low W/p ratios should have favorable friction properties at high temperatures.
Direct Measurement of Net Positive Suction Head
Authors: Jacobs Robert B. , Martin Kenneth B. , Hardy Richard J.
Published: May 2019

A simple, reliable, and accurate method for measuring net positive suction head is described, difficulties which may be encountered in its application are discussed, and test information indicating its reliability and accuracy is presented. The device which embodies the method consists of a vapor-pressure bulb that measures the vapor pressure of the liquid, a pressure tap that measures stagnation pressure, and a pressure gage to indicate (and record, if desired) the difference between the two pressures.
Transitional Phenomena in Ultrasonic Shock Waves Emitted by Cavitation on Hydrofoils
Authors: Numachi F.
Published: May 2019

In some cases during the experiments described in past reports [1, 2] which dealt with cavitation-induced ultrasonic shock waves, extremely anomalous values were obtained in the imparted pressure of the shock waves. The paper deals with an investigation into the nature of these shock-wave anomalies, and it is demonstrated that these anomalies can be caused not only in closed-circuit cavitation tunnels but can be produced in any flow subjected to preliminary cavitation at a point upstream of the point of principal cavitation. The nature of the anomalies occurring in the shock-wave spectrum was studied, and its relation to cavitation-bubble size was made clear.
Thermal-Stress Ratchet Mechanism in Pressure Vessels
Authors: Miller D. R.
Published: May 2019

The combination of cyclic thermal stresses and sustained internal pressure in a vessel is shown to be a source of progressive expansion of the vessel if the stresses are sufficiently high. Criteria presented allow determination of limits to be imposed on stresses in order to prevent progressive expansion or to allow estimation of the expansion per cycle where stresses are sufficient to produce growth. The effect of strain-hardening of the metal on progressive reduction of the growth rate is discussed.
Free Discharge Through a Turbine Distributor, Case, and Draft Tube
Authors: Sutherland R. A.
Published: May 2019

The experience of discharging water freely through the turbine without the runner at the Pelton Hydro-Electric Development in Oregon is described and an indication of the discharge coefficient is given.
Symposium on Welded Spiral Cases From the Manufacturer’s Viewpoint: A Five-Part Symposium
Authors: Fisch J. , Rheingans W. J. , Woodall W. N. , McDonald C. A. , Arnold P. C. , Litzinger L. P.
Published: May 2019

An important but unspectacular part of hydroelectric power developments is the steel spiral case that guides the water from the penstock into the hydraulic turbine. The increasing acceptance of welding and the use of high-strength steels in the construction of spiral cases have permitted and required the development of new construction methods. This report is a condensation of the five prepared statements by representatives of the U. S. and Canadian manufacturers presented at the 1957 Annual Meeting of The American Society of Mechanical Engineers.
Multiaxial Creep Studies on Inconel at 1500 F
Authors: Kennedy C. R. , Harms W. O. , Douglas D. A.
Published: May 2019

Design engineers have become concerned with the effect of multiaxial stresses on the creep rate and on the rupture life of metals as the demands for higher performance have necessitated the use of higher operating temperatures. The goal of applied research in this field is the development of failure criteria based on properties measured in the conventional uniaxial tension creep test.
The Distribution of Contact Pressures in the Rolling of Metals
Authors: MacGregor C. W. , Palme R. B.
Published: May 2019

A comparison is made between the experimentally determined contact pressure distributions obtained on square bars and flat strips. The former showed double peaks in the pressure, one near entry and the other near the roll center line. A pressure peak is obtained near the center line only for strip-rolling.

Two independent analyses were made. One allowed the double peak for the square bars to be predicted with fair accuracy from stress-strain data. The second, based on the local elastic deformation of the rolls, also showed the transition in pressure distributions from billet to strip-rolling.
Fiber
Diameter-Dependent Elastic Deformation in Polymer Composites—A Numerical Study
Authors: Garg Nitin , Chandrashekar Gurudutt , Alisafaei Farid , Han Chung-Souk
Published: May 2019

Microbeam bending and nano-indentation experiments illustrate that length scale-dependent elastic deformation can be significant in polymers at micron and submicron length scales. Such length scale effects in polymers should also affect the mechanical behavior of reinforced polymer composites, as particle sizes or diameters of fibers are typically in the micron range. Corresponding experiments on particle-reinforced polymer composites have shown increased stiffening with decreasing particle size at the same volume fraction. To examine a possible linkage between the size effects in neat polymers and polymer composites, a numerical study is pursued here. Based on a couple stress elasticity theory, a finite element approach for plane strain problems is applied to predict the mechanical behavior of fiber-reinforced epoxy composite materials at micrometer length scale. Numerical results show significant changes in the stress fields and illustrate that with a constant fiber volume fraction, the effective elastic modulus increases with decreasing fiber diameter. These results exhibit similar tendencies as in mechanical experiments of particle-reinforced polymer composites.
Influence of Purge Flow Swirl at Exit to the High-Pressure Compressor on OGV/Pre-Diffuser and Combustion System Aerodynamics
Authors: Walker A. Duncan , Koli Bharat , Beecroft Peter A.
Published: May 2019

As aero gas turbine designs strive for ever greater efficiencies, the trend is for engine overall pressure ratios to rise. Although this provides greater thermal efficiency, it means that cycle temperatures also increase. One potential solution to managing the increasing temperatures is to employ a cooled cooling air system. In such a system, a purge flow into the main gas path downstream of the compressor will be required to prevent hot gas being ingested into the rotor drive cone cavity. However, the main gas path in compressors is aerodynamically sensitive and it is important to understand, and mitigate, the impact such a flow may have on the compressor outlet guide vanes, pre-diffuser, and the downstream combustion system aerodynamics. Initial computational fluid dynamics (CFD) predictions demonstrated the potential of the purge flow to negatively affect the outlet guide vanes and alter the inlet conditions to the combustion system. The purge flow modified the incidence onto the outlet guide vane, at the hub, such that the secondary flows increased in magnitude. An experimental assessment carried out using an existing fully annular, isothermal test facility confirmed the CFD results and importantly demonstrated that the degradation in the combustor inlet flow resulted in an increased combustion system loss. At the proposed purge flow rate, equal to ∼1% of the mainstream flow, these effects were small with the system loss increasing by ∼4%. However, at higher purge flow rates (up to 3%), these effects became notable and the outlet guide vane and pre-diffuser flow degraded significantly with a resultant increase in the combustion system loss of ∼13%. To mitigate these effects, CFD was used to examine the effect of varying the purge flow swirl fraction in order to better align the flow at the hub of the outlet guide vane. With a swirl fraction of 0.65 (x rotor speed), the secondary flows were reduced below that of the datum case (with no purge flow). Experimental data showed good agreement with the predicted flow topology and performance trends but the measured data showed smaller absolute changes. Differences in system loss were measured with savings of around 10% at the turbine feed ports for a mass flow ratio of 1% and a swirl fraction of 0.65.
Effect of the gas to wall temperature ratio on the bypass transition
Authors: Rubini Riccardo , Maffulli Roberto , Arts Tony
Published: May 2019

The study of the boundary layer transition plays a fundamental role in the field of turbomachinery. The main reason is the strong influence of the transition on the flow field local parameters, such as skin friction and heat transfer, this variation is reflected on the global ones such as efficiency and heat load of the blade row.

Turbulent transition models are nowadays commonly used tools in both CFD research and design practice. It is then of particular interest to understand if they are able to predict the effect of temperature on bypass transition and, in case of positive answer, the reasons of their behaviour.

This becomes even more interesting as the effect of the flow aero-thermal coupling becomes prominent in the analysis of such phenomena and is typically not accounted for in the validation of turbulence models. In this work we focus our attention on two state of the art transition model that use two radically different approaches to describe transition.

To isolate the effects of the temperature ratio on the transition the simulations have been performed keeping the same values of Reynolds and Mach numbers and changing the value of the wall to freestream Temperature Ratio (TR).

The results of the two transition models have been compared between them as well as with experimental results. They show that both models are sensitive to TR, though a locally based (rather than correlation based) approach for transition modelling should be favoured.
Discussion Paper on the Use of FPC’s C240 Integrated Compressed Natural Gas (ICNG) Storage Units and TransCanada’s CNG Storage System for the Storage of Natural Gas As a Fuel for Marine Applications
Authors: Lawrence David , Cano Gregory , Williams Steven
Published: May 2019

This discussion paper is based on a preliminary design and is not to be construed or interpreted as being a suitable basis for adoption as a final design for natural gas storage facilities or marine vessels. The gas storage concepts were developed as a basis for project budgeting, further design studies such as HAZID/HAZOP/FEMA, and for review/comment by Classification Societies and Regulatory Authorities as a precedent to further design development. The contents, comments and opinions contained herein are proprietary to Floating Pipeline Company Incorporated and TransCanada.

Paper published with permission.
Hybrid-Powered Marine Vessels
Authors: Hayman Susan , Stratton John
Published: May 2019

In discussing the use of Natural Gas as a fuel for Marine use, there are two aspects that require examination, firstly, the gas handling, process and on land/vessel storage considerations, and secondly, the pressure vessels that will store the fuel.

Paper published with permission.
Emerging Technologies for Treating Contaminants in Marine Wastewater
Authors: Nguyen Don
Published: May 2019

Contaminants in marine wastewater facing current or near-future regulations can be broadly categorized to free oil & suspended solids, emulsified oil and dissolved solids, and biological organisms. The first category of contaminants has been treated by commercially available OWS systems. The second class of contaminants, emulsified oils and dissolved solids, has been effectively treated by UF membrane filtration and to a less extent by biological oxidation and surface modified filters. A survey of recent advances in physical and chemical demulsification technologies to enhance emulsified oil removal with reduced loads on membrane was conducted. The study also identified new applications for treatments of biological organisms in ballast water.

Paper published with permission.
Use of Fuel Cells and ASME Piping Codes for Powering Marine Equipment
Authors: Collins William P.
Published: May 2019

This paper discusses the potential to use fuel cell technology for marine applications. The topics discussed include a definition of a fuel cell, the types of fuel cells and their applications, fuels currently used by various fuel cell designs, the status of supporting product safety standards, the existing model and design codes for the storage and piping of various fuels, the existing model and design codes for the dispensing of various fuels, and potential near term applications for powering marine vessels and other equipment.

Paper published with permission.
OM Code Activities for New Reactors
Authors: Lippy Ronald
Published: May 2019

The ASME (formerly the American Society of Mechanical Engineers) code titled Operation and Maintenance of Nuclear Power Plants (OM Code), Division 1, “Section IST: Rules for Inservice Testing of Light-Water Reactor Power Plants,” defines a post-2000 plant as a nuclear power plant that was issued (or will be issued) its construction permit or its combined license for construction and operation by the applicable regulatory authority on or after January 1, 2000. The New Reactors OM Code (NROMC) Task Group (TG) of the ASME OM Code Committee is assigned the task of ensuring that the preservice testing (PST) and inservice testing (IST) provisions in the ASME OM Code are adequate to provide reasonable assurance that pumps, valves, and dynamic restraints (snubbers) for post-2000 plants will operate when needed. The NROMC TG has prepared updated guidance for pumps and pyrotechnically operated (squib) valves in new reactors that has been incorporated in the ASME OM Code. Currently, the NROMC TG is preparing proposed guidance for surveillance of safety-significant pumps, valves, and dynamic restraints in nonsafety systems at post-2000 plants that employ passive safety-related post-accident heat-removal systems (referred to as passive post-2000 reactors).

The NROMC TG is also evaluating pump and valve surveillance provisions that would ensure that safety-significant components in small modular reactor (SMR) designs are verified to be operationally ready while providing flexibility to accommodate potentially extended refueling cycles associated with these post-2000 plants. There are several other changes and evaluations being performed by the NROMC TG to provide reasonable assurance of the operational readiness of safety-significant pumps, valves, and dynamic restraints while still weighing the cost-effectiveness of the requirements. The NROMC TG also considers risk insights in its evaluation of PST and IST provisions for post-2000 plants. This paper discusses the NROMC TG activities to develop the recent and planned improvements to the PST and IST provisions in the ASME OM Code to address pumps, valves, and dynamic restraints in new reactors.

Paper published with permission.
A Description of Data-Analysis Techniques
Authors: Files Christina
Published: May 2019

Trending, standard deviation, forecasting, linear regression, anomaly detection, and normalization are all techniques that IST Program Engineers use as tools to help them analyze and evaluate test results. But does the program engineer remember what these terms mean? Are they being used correctly? Are the techniques being used when they need to be? Are their benefits being fully used? This paper briefly goes over what each of these terms mean and looks at examples of each. Knowing how to use these tools is integral to a quality IST Program. Some software, such as True North Consulting’s EP-Plus Engage IST Software, incorporates these “value added” techniques. A brief overview of how they are used as tools for the IST Engineer is provided. Also included is a discussion on how these tools can be improved on and leveraged to decipher the program engineer’s IST Program data.

Paper published with permission.
Regulatory Requirements and Perspectives on the Use of Inservice Testing Software in the Nuclear Industry
Authors: Carneal Jason B.
Published: May 2019

The American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) establishes the requirements for preservice and inservice testing (IST) and examination of certain components to assess their operational readiness in light-water reactor nuclear power plants. The Code of Federal Regulations (CFR) endorses the use of the ASME OM Code in 10 CFR 50.55a(b)(3) . This paper focuses on applicable regulatory requirements and regulatory perspectives associated with the use of IST software in the nuclear industry.

Paper published with permission.
ASME OM Code Appendix IV
Authors: Setzer Fred
Published: May 2019

This paper presents a discussion of the activities ongoing within the ASME (formerly the American Society of Mechanical Engineers) Operation and Maintenance of Nuclear Power Plants (OM) Code Subgroup on Air Operated Valves (SG-AOV), along with an overview of Revision 0 of Mandatory Appendix IV, “Preservice and Inservice Testing of Active Pneumatically Operated Valve Assemblies in Light-Water Reactor Power Plants.”

Paper published with permission.
Regulatory Perspectives on Risk-Informed Inservice Testing
Authors: Billerbeck John
Published: May 2019

In this paper, we review the various regulatory mechanisms that are available to licensees today for risk-informing their IST programs and that are acceptable to the NRC staff. These mechanisms have all been available for a decade or more, but have seen little interest or use.

Paper published with permission.
Preliminary Study of the Use of Freeze-Valves for a Passive Shutdown System in Molten Salt Reactors
Authors: Li Qiming , Tang Zhongfeng , Fu Yuan , Li Zhong , Wang Naxiu
Published: May 2019

The use of passive shutdown systems to enhance safety is one element of next-generation reactor design. The Freeze-Valve has been proposed as a key device in the passive system to stop the chain reaction of the Molten Salt Reactor (MSR), which has been chosen by Generation IV International Forum (GIF) as one of the six Generation IV reactor concepts. During reactor normal operation, the molten salt in the valve is cooled to a solid plug. In the event that the reactor overheats under accident conditions when all other active control systems fail, the plug will melt. The liquid fuel salt will be pulled out from the reactor core by gravity into dump tanks, and criticality will cease because the reaction is no longer moderated by the graphite in the reactor core. The more accurate the Freeze-Valve’s thermal design is, the more efficient the passive shutdown system becomes. In this study, an investigation of the thermal performance of the Freeze-Valve is conducted based on finite element methods verified by experimental data, and some modified designs are presented with recommendations. For further consideration, some innovative governing techniques used to control the Freeze-Valve are discussed in detail. Here, a more critical thermal design is focused on that can make the passive system shut down the nuclear reactor quickly and reliably. The Freeze-Valve can be used in the molten salt loop rather than a mechanical valve, which may become jammed by frozen salt.

Paper published with permission.
Inservice Testing Program Improvements for New Reactors: Small Modular Reactors
Authors: Lippy Ronald
Published: May 2019

The nuclear industry is preparing for the licensing and construction of new nuclear power plants in the United States. Several new designs have been developed, including more traditional evolutionary designs, passive reactor designs, and small modular reactors (SMRs).

ASME (formerly the American Society of Mechanical Engineers) provides specific codes used to perform inspections and testing, both preservice and inservice, for many of the components used in the new reactor designs. The U.S. Nuclear Regulatory Commission (NRC) reviews information provided by applicants related to inservice testing (IST) programs for design certification (DC) and combined license (COL) applications under Part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” of Title 10, “Energy,” of the Code of Federal Regulations (10 CFR Part 52) (Reference 1).

The 2012 Edition of the ASME OM Code, Operation and Maintenance of Nuclear Power Plants, defines a post-2000 plant as a nuclear power plant that was issued (or will be issued) its construction permit, or combined license for construction and operation, by the applicable regulatory authority on or after January 1, 2000. The ASME New Reactors OM Code (NROMC) Task Group (TG) is assigned the task of ensuring that the preservice testing (PST) and inservice testing (IST) provisions in the ASME OM Code are adequate to provide reasonable assurance that pumps, valves, and dynamic restraints (snubbers) for post-2000 plants will operate when needed. Currently, the NROMC TG is preparing proposed guidance for the treatment of active pumps, valves, and dynamic restraints with high safety significance in nonsafety systems for passive post-2000 plants, including SMRs. (Note: For purposes of this paper, “post-2000 plant” and “new reactor” are used interchangeably throughout.)

Paper published with permission.
Implementation of Snubber Service-Life Monitoring Programs
Authors: Shutt Mark
Published: May 2019

A well-planned and -implemented service-life program which is properly used can reduce the need for extended testing and examination activities and can result in a cost-effective overall program. Service-life monitoring is an essential part of an effective snubber program, yet it is often the least detailed and most overlooked aspect. Because of the historical emphasis on examination and testing requirements, there has been little industry-wide consistency or emphasis on the specifics of service-life monitoring activities. This paper will identify the purpose and basis for snubber service-life requirements, as well as outline key elements of an effective program to both identify service-life values and monitor them over periods of extended plant operation.

Included in the discussion will be topics such as: Identifying regulatory and code requirements, determining the scope of the program, establishing original service-life values, monitoring and evaluation, adjusting values, program documentation, and reporting. Identifying pertinent parameters for monitoring, appropriate methods for monitoring and trending, and incorporating condition monitoring and preventive-maintenance activities as alternatives to traditional programs will be discussed. Common challenges to implementing an effective program will be addressed, as well as some pitfalls to be avoided.

Paper published with permission.
Alternative Selection of Pump-Test Instrumentation and Variance of Fixed Reference Values
Authors: Gowin Mark , Robinson Tom , Kin John
Published: May 2019

This paper describes actions being taken by the ASME (formerly the American Society of Mechanical Engineers) Operation and Maintenance of Nuclear Power Plants (OM Code) Subgroup on Pumps (ISTB) to revise pump test requirements to be more clearly stated and provide more flexibility in performance of tests. Specifically, this paper addresses two aspects of pump test requirements that are in the process of being changed.

• Instrumentation requirements for measurement of hydraulic parameters (approved by ISTB subgroup).

• Variance around the fixed reference value for establishing pump-test conditions (approved by ASME and published in the 2012 Edition of the OM Code).

The OM Code changes discussed in this paper are currently in various stages of approval and endorsement. Therefore, the information provided in this paper is subject to change as a result of the OM Code approval and U.S. Nuclear Regulatory Commission (NRC) endorsement processes.

Paper published with permission.
Application of Phased Array Sectorial Scanning (PASS) to Determine Check-Valve Operational Readiness at the Palo Verde Nuclear Station
Authors: Cruz Domingo A. , Delgado Jesse R.
Published: May 2019

The reliability of check valves is paramount to the safe operation of plant systems. This paper provides a description of the benefits of applying advanced phased array techniques to establish the operational readiness of swing-check valves in the static or dynamic operational modes. In addition, a utility model perspective is described explaining how the Phased Array Sectorial Scanning (PASS) data assessments can be used to support operational predictive maintenance decisions. A collaborative effort between Arizona Public Service Co., the Palo Verde plants, and IHI Southwest Technologies, Inc. (IHI), was realized when IHI personnel applied Phased Array Sequence Scanning techniques to swing-check valves operating in the closed static position, as well as to three identical valves operating in the dynamic open positions in Palo Verde Units 1, 2 and 3 respectively.

Paper published with permission.
Organs-on-chips take baby steps
Authors: McCain Megan L.
Published: May 2019

Two organ-on-chip devices enable investigation of cellular interactions in human fetal membranes in vitro.
Non-infectious aortic and mitral valve vegetations in a patient with eosinophilic granulomatosis with polyangiitis
Authors: Karthikeyan Kamalesh , Balla Sudarshan , Alpert Martin A
Published: May 2019

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of vasculitis characterised by atopic manifestations, inflammation of small-sized to medium-sized arteries and veins, hypereosinophilia and tissue infiltration with eosinophils. Cardiac complications occur most commonly in the absence of antineutrophil cytoplasmic antibodies. Cardiac complications include coronary arteritis (rare), pericarditis, myocarditis, endocardial fibrosis (Loeffler’s endocarditis) and intracavitary thrombosis of the left or right ventricle. This is the first reported case of large non-infectious valvular vegetations associated with EGPA.
Non-classical monocyte homing to the gut via α4β7 integrin mediates macrophage-dependent intestinal wound healing
Authors: Schleier Lena , Wiendl Maximilian , Heidbreder Karin , Binder Marie-Theres , Atreya Raja , Rath Timo , Becker Emily , Schulz-Kuhnt Anja , Stahl Annette , Schulze Lisa Lou , Ullrich Karen , Merz Simon F , Bornemann Lea , Gunzer Matthias , Watson Alastair J M , Neufert Clemens , Atreya Imke , Neurath Markus F , Zundler Sebastian
Published: May 2019

Objective

To study the role of α4β7 integrin for gut homing of monocytes and to explore the biological consequences of therapeutic α4β7 inhibition with regard to intestinal wound healing.

Design

We studied the expression of homing markers on monocyte subsets in the peripheral blood and on macrophage subsets in the gut of patients with IBD and controls with flow cytometry and immunohistochemistry. Integrin function was addressed with dynamic adhesion assays and in vivo gut homing assays. In vivo wound healing was studied in mice deficient for or depleted of α4β7 integrin.

Results

Classical and non-classical monocytes were clearly dichotomous regarding homing marker expression including relevant expression of α4β7 integrin on human and mouse non-classical monocytes but not on classical monocytes. Monocyte-expressed α4β7 integrin was functionally important for dynamic adhesion to mucosal vascular addressin cell adhesion molecule 1 and in vivo gut homing. Impaired α4β7-dependent gut homing was associated with reduced (effect size about 20%) and delayed wound healing and suppressed perilesional presence of wound healing macrophages. Non-classical monocytes in the peripheral blood were increased in patients with IBD under clinical treatment with vedolizumab.

Conclusion

In addition to reported effects on lymphocytes, anti-α4β7 therapy in IBD also targets non-classical monocytes. Impaired gut homing of such monocytes might lead to a reduction of wound healing macrophages and could potentially explain increased rates of postoperative complications in vedolizumab-treated patients, which have been observed in some studies.