bluuebunny/crossref_metadata_2025 huggingface dataset:
Operating Results of an Experimental Supercritical Steam Generator
Authors: Daman E. , Phillips H. , Vail J. , Ling S.
Published: May 2019

This paper presents some of the results achieved with a 2000 lb/hr supercritical pilot plant after 5000 hours of operation. Data on water side conditioning and the effect of final steam temperature on corrosion rate are presented. The paper also describes a successful automatic control system which was developed. Tests and test results from control runs are presented and it is shown how these results can be applied to the design of central station once-through steam generator control systems.
Some Notes on the Strength of the Enrico Fermi Reactor Vessel Structure
Authors: Beyer F. R.
Published: May 2019

The place and function of the reactor vessel in the Enrico Fermi Atomic Power Plant—the most complex nuclear structure built to date—is described. The design basis must lead to a conservative structure. Evaluation of the design of any new and radically different structure must be based upon tests. Strain gaging during hydrostatic testing gave limited results. High-temperature strain gages will be used during simulated-service tests prior to start-up. A successful high temperature strain-gaging technique for long-time static applications up to at least 900 F is developed and described.
Design of 321-Mw Cross-Compound Steam Turbine—River Rouge Unit No. 3
Authors: Wilson C. D.
Published: May 2019

This paper discusses the design features and general arrangement of a 321-mw close-coupled cross-compound 3600/1800-rpm steam turbine-generator unit. The machine is designed for operation with subcritical pressures and with steam temperatures that permit using ferritic materials. It was the first machine to be ordered in the 300-mw size range and is installed in the River Rouge Station of The Detroit Edison Company.
A Simplified Regenerator Theory
Authors: Schalkwijk W. F.
Published: May 2019

Most regenerators encountered in practice have simple linear or exponential temperature fields in their central parts. This leads to the possibility of a simplified representation of the regenerator efficiency with sufficient accuracy for all practical cases. In the important “symmetrical” case, in which the parameters have the same value in both directions of gas flow, the efficiency can be represented by a single curve. This case is treated extensively in this paper. The results for the general case are given in an Appendix. Here also a reduction is achieved of the number of parameters needed to represent the efficiency.
Compound Piston-and-Turbine Engines
Authors: London A. L.
Published: May 2019

The prime-mover combination of piston-and-cylinder components with a high-speed exhaust-gas turbine and, in some cases, a centrifugal or axial-flow compressor has assumed a variety of forms. Progress in the development of some of the more notable members of this family of compound engines is presented.
Automotive
Authors: Schwartz Frank L.
Published: May 2019

Many experimental models of gas turbines have been built for vehicle propulsion, and indications are that production models may be available within the next decade. Special effort has been devoted in recent years to improving the fuel consumption by adding heat exchangers to the originally proposed simple-cycle gas turbines. If they are to be competitive with reciprocating engines, gas turbines must not only be equal or better in performance, but equal or lower in cost. This would require manufacture in large quantities, and it is very likely that the first production models will be in a low-priced high-production automobile.
A New Performance Criterion for Steam-Turbine Regenerative Cycles
Authors: Salisbury J. Kenneth
Published: May 2019

This paper presents an explanation and discussion of a heretofore unexploited criterion of the performance of the regenerative cycle. It is demonstrated that this simple criterion, the flow-weighted average extraction enthalpy, embodies in a single variable all of the effects of extracting steam for feedwater heating, and permits quick and direct estimation of the effect of any cycle change on heat rate. Thus the new variable is useful in both design and performance monitoring of the thermal cycle, as well as in estimating the improvement that is realized by regeneration.
A Boundary-Layer Treatment of Laminar-Film Condensation
Authors: Sparrow E. M. , Gregg J. L.
Published: May 2019

The problem of laminar-film condensation on a vertical plate is attacked using the mathematical techniques of boundary-layer theory. Starting with the boundary-layer (partial differential) equations, a similarity transformation is found which reduces them to ordinary differential equations. Energy-convection and fluid-acceleration terms are fully accounted for. Solutions are obtained for values of the parameter cpΔT/hfg between 0 and 2 for Prandtl numbers between 1 and 100. These solutions take their place in the boundary-layer family along with those of Blasius, Pohlhausen, Schmidt and Beckmann, and so on. Heat-transfer results are presented. It is found that the Prandtl-number effect, which arises from retention of the acceleration terms, is very small for Prandtl numbers greater than 1.0. Low Prandtl number (0.003–0.03) heat-transfer results are given in Appendix 2, and a greater effect of the acceleration terms is displayed.
Natural-Convection Heat Transfer in Liquids Confined by Two Horizontal Plates and Heated From Below
Authors: Globe Samuel , Dropkin David
Published: May 2019

This paper presents results of an experimental investigation of convective heat transfer in liquids placed between two horizontal plates and heated from below. The liquids used were water, silicone oils of 1.5, 50, and 1000 centistoke kinematic viscosities, and mercury.

The experiments covered a range of Rayleigh numbers between 1.51(10)5 and 6.76(10)8. and Prandtl numbers between 0.02 and 8750.

Tests were made in cylindrical containers having copper tops and bottoms and insulating walls. For water and silicone oils the container was 5 in. in diam and 2 in. high. For mercury, two containers were used, both 5.28 in. in diameter, but one 1.39 in. high and another 2.62 in. high. In all cases the bottom plates were heated by electric heaters. The top plates were air-cooled for the water and silicone-oil experiments and water-cooled for the mercury tests. To prevent amalgamation, the copper plates of the mercury container were chromium plated.

Surface temperatures were measured by thermocouples embedded in the plates.

The test results indicate that the heat-transfer coefficients for all liquids investigated may be determined from the relationship Nu=0.069Ra13Pr0.074

In this equation the Nusselt and Rayleigh numbers are based on the distance between the copper plates.

The results of this experiment are in reasonable agreement with the data reported by others who used larger containers and different fluids.
Generalized Correlation of Boiling Heat Transfer
Authors: Levy S.
Published: May 2019

A generalized equation to describe surface boiling of liquids is derived. The expression which correlates all fluid independently of pressure and heating surface-fluid combination is QA=kLCLρL2σTsρL-ρV1BLΔT3

The form of the relation was obtained from a simplified model of heat transfer to the bubbles close to the heated surface. The coefficient BL, determined empirically, was found to be a function only of the product ρVhfg and is shown in Fig. 4.

Good agreement between test results and the derived equation was obtained for pool boiling and nucleate boiling heat transfer of subcooled and vapor-containing liquids.
Calculation of Transients in a Cross-Flow Heat Exchanger
Authors: Dusinberre G. M.
Published: May 2019

This paper shows how transient temperatures in a cross-flow heat exchanger may be calculated by numerical methods. Digital computer programming is considered. A gas-turbine regenerator is used as an example. In particular, methods are developed which are useful when the flow rates vary, as in the starting transient.
Heat Transfer Between Concentric Rotating Cylinders
Authors: Bjorklund I. S. , Kays W. M.
Published: May 2019

In this paper the problem of convective heat transfer between concentric rotating cylinders is studied. Experimental heat-transfer data are presented for four different values of clearance between the cylinders and for several combinations of outer to inner cylinder speed. The heat-transfer performance indicates three regimes of flow; the first at low peripheral velocities, in which laminar flow and heat transfer by conduction prevail, the second at cylinder speeds above a theoretically predictable value, in which vortex flow occurs and is the controlling mechanism, and a third at still higher speeds, in which a distorted type of vortex motion may be present. The data for the case of the inner cylinder only rotating can be correlated by the equation NNu/NNucond=0.175NTa12 for the Taylor number range 90 to 2000. A heat-and-momentum-transfer-analogy solution for this case follows the trend of the data, but gives results which are somewhat high. The combined effects of rotation of both cylinders may be correlated by the empirical equation NNuNNucond=1.1NTa-NTacrη-NTacr01-3.5d/R141.1+NTacrη-NTacr03.5d/R112 for values of the abscissa from about 2 to 50.
A Photographic Study of Boiling in the Absence of Gravity
Authors: Siegel R. , Usiskin C.
Published: May 2019

A photographic study was made to determine the qualitative effect of zero gravity on the mechanism of boiling heat transfer. The experimental equipment included a container for boiling water and a high-speed motion-picture camera. To eliminate the influence of gravity, these were mounted on a platform which was allowed to fall freely approximately 8 ft. During the free fall, photographs were taken of boiling from various surface configurations such as electrically heated horizontal and vertical ribbons. The heat flux was varied to produce conditions from moderate nucleate boiling to burnout. The results indicate that gravity plays a considerable role in the boiling process, especially in connection with the motion of vapor within the liquid.
Some General Considerations of the Heating of Satellites
Authors: Eggers Alfred J. , Wong Thomas J. , Slye Robert E.
Published: May 2019

Heating of satellites is treated in connection with flight in planetary atmospheres and in interplanetary space. Heating during entry into the earth’s atmosphere is generally more severe than that encountered during launch or exit, although it can be substantially reduced by employing blunt shapes and small entry angles. Decelerations and heating rates during entry can be further reduced by employing lifting satellites. These techniques in combination with known radiation, heat-sink, and ablation cooling techniques appear adequate to handle the entry problem at speeds up to escape speed. Return flights from distant planets like Saturn and beyond may be characterized by much higher entry speeds, and more advanced techniques for coping with the heating problem may be required. Heating during entry into the atmospheres of planets neighboring Earth tends to be more or less severe than that in the earth’s atmosphere depending on whether the planets are larger or smaller than Earth.

Heating in interplanetary space due to solar radiation becomes severe only if a satellite approaches to within a small fraction of an astronomical unit of the sun, or if the vehicle has an inefficient radiation shield. A cooling problem is encountered in the outer portion of our solar system, and an auxiliary power source may be required to supplement the reduced amount of heat from the sun. The sputtering or erosion of material from the surface of a satellite, caused by impact at hypervelocities with small particles in space, may also pose direct or indirect heating problems. Further research is required to assess the magnitude of these problems.
Design of Helical Springs for Minimum Weight, Volume, and Length
Authors: Hinkle R. T. , Morse I. E.
Published: May 2019

In the design of helical springs where the load, deflection, allowable stress, and material are specified, there are an infinite number of solutions. In this paper, equations and graphs are presented for the selection of a spring index that will result in a spring of minimum weight, volume, or length. If, an addition to these requirements, the inside or outside diameter of the spring is fixed, there is only one solution. Equations and graphs are included for the selection of the spring index which will satisfy this additional requirement.
Stress and Strain in Spinning Paraboloid Dishes
Authors: Cohen M. J.
Published: May 2019

The following is an investigation to determine completely the state of stress and strain in spinning paraboloid dishes both whole and holed at the center. The material of the dish is homogeneous and its thickness is constant. The results comprise expressions for the radial, hoop, and shear stresses, the bonding moments, and deformation induced by the spinning of the dish in terms of the angular distance from the center of the dish. Tables at the end of the paper make the actual evaluation of these stresses, moments, and deformations a matter of simple arithmetic.
Torispherical Shells—A Caution to Designers
Authors: Galletly G. D.
Published: May 2019

It has recently become apparent, through a rigorous stress analysis of a specific case that designing torispherical shells by the current edition of the ASME Code on Unfired Pressure Vessels can lead to failure during proof-testing of the vessel. The purpose of the present paper is to show in what respects the Code fails to give accurate results. As an illustrative example, a hypothetical pressure vessel with a torispherical head having a diameter-thickness ratio of 440 was selected. The supports of the vessel were considered to be either on the main cylinder or around the torus. The vessel was subjected to internal pressure and the elastic stresses in it were determined rigorously and by the Code. A comparison of the two revealed that the Code predicted stresses in the head which were less than one half of those actually occurring. Furthermore, the Code gave no indication of the presence of high compressive circumferential direct stresses which exceeded 30,000 psi for practically the entire torus. If the head had been fabricated using a steel with a yield point of 30,000 psi, then a limit analysis shows that it would have failed or undergone large deformations, whereas the Code would have predicted that it was safe. The Code’s rules for torispherical heads are thus in need of revision for certain geometries. The implications of the foregoing results are currently being studied by the ASME; in the interim, however, designers should exercise care in applying the Code to torispherical shells.

It is also shown in the paper that the use of the membrane state as a particular solution of the differential equations is not a good approximation for toroidal shells of the type considered.
Drilling by Vibration
Authors: Simon R.
Published: May 2019

An analysis is presented of the process of vibratory drilling, based on the assumption that the load presented by the bit vibrating on the rock to the vibration generator, a magnetostriction transducer, can be represented by a force-displacement characteristic with hysteresis. The conclusions reached are compared with experimental observations on the performance of vibratory drilling systems.
The Strength of Thick-Walled Cylinders
Authors: Crossland B. , Jorgensen S. M. , Bones J. A.
Published: May 2019

Comprehensive pressure tests have been carried out on thick-walled, closed-ended cylinders made from a mild steel and a hardened and tempered steel, the maximum pressure reached being 94,000 lb/in.2 The complete theoretical behavior of the cylinders is computed from shear stress-strain data obtained from torsion tests and is shown to be in very close agreement with the experimental results. In addition, a method is given for deriving the large strain behavior of the cylinders from tension test data. When compared with the experimental results this approach gives larger errors, the theoretical values of pressure being consistently high. Finally, ultimate pressures have been calculated from two empirical expressions.
Steady-State Creep Analysis of the Weight Loadings of Furnace Tubes on Multiple Supports
Authors: Jacobowitz J. L. , Mader C. K.
Published: May 2019

Analysis of creep stress-strain relationships is made for horizontally supported furnace tubes including the effect of tube weight and internal pressure. Steady-state creep effects through the tube wall due to axially symmetrical heal input are also analyzed for these conditions. The original Bailey approach to the pressure problem only is extended to the larger scope undertaken. Maximum permissible tube spans are derived based on accepted criteria for creep stress and deflections.

The results of this work indicate that maximum allowable tube spans may often be theoretically increased beyond present usual design limits except for a few specific materials and instances where short spans are required at very high temperatures. In actual tube design, consideration should be given to experience in operation of any particular type of furnace so that secondary effects may be minimized. Increased economies in costs and flexibility in furnace layout as well as rational span determination are expected from use of these results.
Synthesis of the Four-Bar Linkage to Match Prescribed Velocity Ratios
Authors: Barkan Philip , Tuohy E. J.
Published: May 2019

A method is described for synthesizing a four-bar linkage in terms of its velocity ratio at two or three positions of the input crank. The two-point synthesis problem is readily solved by either graphical or longhand mathematical techniques. The method also lends itself to computer solution for the three-point synthesis problem and also for determining the best match of a desired function over a specified range of input crank motion.
The Effect of Process Variables on Extrusion Pressures of Lead
Authors: Frisch J. , Thomsen E. G.
Published: May 2019

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.
Approximate Solutions to a Problem of Press Forging
Authors: Kobayashi S. , Thomsen E. G.
Published: May 2019

The velocity vectors in the flash and body of a press forging of commercially pure lead having axial symmetry were obtained experimentally from incremental displacements in stepwise forging operations. It was found that the velocities are in excellent agreement with those derived with the aid of a simple disk theory, where it was assumed that all deformation is concentrated in a fictitious disk. Comparison with velocities derived from certain slip-line solutions also shows that substantial agreement exists here between theory and experiment.

Calculated average forging pressures, which were obtained by the approximate disk and slip-line theories, are in approximate agreement and the local pressure distributions are similar. These results seem to clarify the role which the flash height and friction in the die-lands play in achieving a good impression of the die cavities.
Development and Uses of a New Line of Vibratory Feeders and Unit Vibrators
Authors: Israelson Arlo F.
Published: May 2019

Highlights in the development of an entirely new electropermanent magnetic motor drive and a new disk-type springing system through the use of a laminated fiberglas-epoxy resin product, resulting in an outstanding line of vibratory feeders and unit or bin vibrators. Also some of the many uses for these products in controlled materials handling, as well as engineering information which should be considered in the selection and application of these versatile performers.
Concerning Subharmonic Oscillations Which May Exist in Nonlinear Systems Having Odd Restoring Forces
Authors: Ludeke C. A. , Pong William
Published: May 2019

An experimental study is made of subharmonic oscillations in systems having |θ|θ, θ3, and |θ3|θ as the nonlinear terms in the restoring force; θ represents displacement. In a system with a restoring force θ3 the subharmonic of order one third was the only subharmonic observed. In a system with |θ|θ or |θ3|θ as the restoring force, subharmonics of order one half and one third were observed.
Antifriction Instrument-Bearing Torque Testing and the Resistance to Motion of Such Bearings
Authors: Asch A. B.
Published: May 2019

The inertial guidance of airplanes and missiles has focused attention on the subject of friction torque of instrument ball bearings. Several years ago the Department of Defense undertook the task of standardizing the rating of the motion-resisting torque of such bearings, and the development of a tester for this purpose. This paper briefly discusses the Mil-Std-#206 torque tester, the interpretation of its results, and some of the frictional properties of instrument antifriction bearings. A cutaway illustration shows the arrangement of configuration of the tester; and a schematic of the system, with the related description, explains the principle of operation. Also a typical torque trace from the tester is reproduced and analyzed.
Characteristics of a Self-Lubricated Stepped Thrust Pad of Infinite Width With Compressible Lubricant
Authors: Kochi Kikuo C.
Published: May 2019

Harrison’s equation for the pressure in a gas-lubricated bearing of infinite width is solved for a thrust pad with stepped configuration. Analytic expressions for the pressure and load are developed. Numerical results are presented graphically. The analytic expressions together with the numerical data permit most of those characteristics of the stepped pad of practical interest to be completely determinable. Determination of optimum design parameters is given by a pair of graphs.
Refractory Metal Facings for Protection of Metal Surfaces Subjected to Repeated High-Temperature Pulses
Authors: Cohen Aaron , Homer Edward
Published: May 2019

Because the operating frequency of a magnetron has a direct relationship to the size of the resonant structure, the power at a given frequency that can be obtained from a magnetron may be limited by the temperature which the resonating structure can withstand. A rise in the temperature of the resonant structure is caused by the impact of high-energy electrons emitted from the cathode at high peak-power levels for short durations. This paper deals with the analytical determination of the temperature of the resonant structure, a solution to the heat problem in which a thin coating of refractory metal is used to prevent the vulnerable components from melting, and some experimental results to verify the analysis.
On the Nature of Stall
Authors: Kline Stephen J.
Published: May 2019

The physical data available on the problem of stall are reviewed. The discussion is centered on the problem of flow in passages. The emphasis is placed on systematic visual data showing flow patterns as a function of geometrical parameters. These data lead to a view of stall as a spectrum including three or possibly four major types of flow patterns; these patterns involve both transient and steady elements. A qualitative parameter is formulated which provides a classification for the major types of stall. It is shown that this parameter and its underlying concepts are useful in rationalizing known but previously inexplicable results and in obtaining important qualitative predictions. Comparisons between the predictions of boundary-layer theory and the actual systematic stall data of passages are given.
Centrifugal Manometer
Authors: Kemp J. F.
Published: May 2019

The operating principles and mechanical construction of a micromanometer, which utilizes air in lieu of a liquid as working fluid, are described. Some of the noteworthy features of the instrument include its high sensitivity and accuracy, quick response, wide range, and ease of manipulation. Differential pressures of the order of 5 × 10−3 mm water gage can be measured with an error of 1 per cent under normal laboratory conditions. The maximum range of the prototype described is 25 mm water gage, and the corresponding error at this value amounts to about 0.25 per cent.
Loss and Stall Analysis of Compressor Cascades
Authors: Lieblein Seymour
Published: May 2019

A simple equation expressing the wake momentum thickness as a primary function of the suction-surface diffusion ratio (ratio of maximum surface velocity to outlet velocity) of coaventional low-speed cascade blades is derived from boundary-layer theory in conjunction with simplifying approximations. The derived equation is utilized to gain an insight into qualitative effects on stalling diffusion ratio of such factors as Reynolds number, transition location, and extent of local laminar separation. Use of parameters suggested by the analysis is shown to result in generalized experimental loss and stall correlations and in means for estimating total-pressure loss and unstalled range of operation for commonly used blades.
Modulation Phenomena in Stall Propagation
Authors: Rockett John A.
Published: May 2019

Recent experimental work on stall propagation in a single-stage research compressor is described. At certain fixed operating points, several different stall patterns were found to exist. Transitions from one pattern to the other occurred spontaneously, reversibly, and fairly frequently. These transitions were studied in detail. A regular modulation of the stall-propagation velocity is associated with the transition process. The modulation is used to determine stall frequency as a function of both wave number and mass flow. Stall-cell size measurements, static-pressure surveys, and a study of the region downstream of the stall-propagating rotor are described.
Applications of Computer and Model Studies to Problems Involving Hydraulic Transients
Authors: McCaig I. W. , Jonker F. H.
Published: May 2019

This paper discusses the application of digital and analog computers to surge and water-hammer problems. It also indicates that, for some problems in hydraulic transients for which the basic hydraulic equations are uncertain, an electrically controlled model can give the most reliable and economical solution.
Experience in the Use of the Gibson Method of Water Measurement for Efficiency Tests of Hydraulic Turbines
Authors: Gibson Norman R.
Published: May 2019

The purpose of this paper is to examine the records of experience, for 35 years from 1920 to 1955, in the use of the Gibson Method and Apparatus, for measuring the flow of water as applied in field efficiency tests of turbines in hydro-electric power plants.

Diagrams based on tables of maximum efficiencies of comparable units, from a total of 310 tests are presented. A few unusual experiences are cited and described. A comprehensive discussion of the accuracy of the method is given; with particular reference to the critical analyses of Francis Salgat and the late Dieter Thoma and others and to the precision which can be expected in determining the various factors required for measuring water quantities by this method.

Four appendixes give: (1) A brief description of the Gibson Method and Apparatus; (2) some slight revisions of the author’s original paper published by ASME in 1923; (3) a numerical example of the delineation and computation of a differential pressure-time diagram; and (4) a partial Bibliography with notes.
Application and Analysis of a Computer Control System
Authors: Lefkowitz Irving , Eckman Donald P.
Published: May 2019

The electronic computer offers the possibility of achieving complete and precise control of physical systems. An application of particular interest is the computer control of industrial processes to specified criteria of performance; e.g., control of the process such that product of uniform, specified quality is produced under conditions of minimum cost.

A computer control application to a batch-type process is presented. The method of control, based on repetitive computer action and fast-time scaling makes it possible to obtain a specified end point consistent with a prescribed criterion of optimum performance.

Dynamic analysis of the computer control system is difficult because of the nonlinear and sampled-data characteristics of the computer element. A method for approximate determination of system behavior based on perturbation techniques is described. It is shown, in particular, that the effect of a disturbance signal on the processing path varies in almost direct proportion with the sampling period. Thus, by making the sampling period small relative to the duration of the process, simplifying approximations to the mathematical model may be employed in the derivation of the computer-control equations.

The study is augmented by data on computer control of a three-component-batch chemical process. The results of the dynamic analysis are compared qualitatively with the experimental results of predictor and optimizing control runs.
Electromagnetic Flowmeter Primary Elements
Authors: Head V. P.
Published: May 2019

An obstructionless flowmeter for electrically conducting liquids is described. Tentative design and inspection criteria which have been found to provide accuracies of ±1/2 per cent, or as little as ±0.005 fps pipeline velocity, are set up. A practical threshold conductivity of meterable liquids is set at 20 micromhos per cm, though there is every reason to believe this will be drastically cut with further progress. Above this threshold, the flow coefficient in the volume-rate equation is shown by tests to be independent of the conductivity, of the Reynolds number, and of installation conditions.
Solar Thermal Panels for Small-Medium Scale Air Cleaners in Major Cities
Authors: Arias Francisco J. , Heras Salvador De Las
Published: May 2019

Air quality in major cities is reaching worrisome levels across the planet owing to large-scale industrialization. As a result, air purification systems are becoming a fertile and emerging field for research. Here, consideration is given to the use of a small-medium scale air purification system for cities using a kind of solar thermal panels by inducing local convective currents intended to be used in parks, housing estates, or similar urban places providing a local improvement of the quality of the air. The main difficulty which arose when attempting to use these convective currents is that the upward flow of hot air, which has been cleaned from contaminant particles during its upward travel, must be returned back to the ground. To accomplish this, air must be cooled during the travel in order to obtain an effective buoyancy. Several possible solutions have been proposed in the past, for example, the use of a dedicated cooling system as is the use of water spraying systems which could be an attractive option for large towers. However, for small-medium scale air cleaners, dedicated spraying cooling systems are out of question either because of the requirement of water flow or because of the high local humidity generated which can be uncomfortable for humans. One possible solution could be taking advantage of vertical panels in which a side of the panel is permanently irradiated and the other is permanently in the shadow; in this way, heating and cooling could be performed eliminating the need for specialized cooling systems, and although the effective buoyancy—and then the purified air mass flow—of such a system is considerably reduced, nevertheless, it could still be acceptable for local small-scale applications. Utilizing a simplified physical model, the effective buoyancy and attainable air mass flow were calculated. It is shown that for a small panel of 5 m-height or thereabouts, an air flow per unit of width ∼0.4 kg/s is attainable, and for a 10 m-height panel, an air flow per unit of width 0.6 kg/s is attainable. Computational fluid dynamics simulations were performed which agree with the analytical results within ±30 %.
High Degree of Freedom Hand Pose Tracking Using Limited Strain Sensing and Optical Training
Authors: Zhang Wentai , Yu Jonelle Z. , Zhu Fangcheng , Zhu Yifang , Yang Zhangsihao , Ulu Nurcan Gecer , Arisoy Batuhan , Kara Levent Burak
Published: May 2019

The ability to track human operators' hand usage when working in production plants and factories is critically important for developing realistic digital factory simulators as well as manufacturing process control. We propose a proof-of-concept instrumented glove with only a few strain gage sensors and a microcontroller that continuously tracks and records the hand configuration during actual use. At the heart of our approach is a trainable system that can predict the fourteen joint angles in the hand using only a small set of strain sensors. First, ten strain gages are placed at various joints in the hand to optimize the sensor layout using the English letters in the American Sign Language (ASL) as a benchmark for assessment. Next, the best sensor configurations for three through ten strain gages are computed using a support vector machine (SVM) classifier. Following the layout optimization, our approach learns a mapping between the sensor readouts to the actual joint angles optically captured using a Leap Motion system. Five regression methods including linear, quadratic, and neural regression are then used to train the mapping between the strain gage data and the corresponding joint angles. The final proposed model involves four strain gages mapped to the fourteen joint angles using a two-layer feed-forward neural network (NN).
Numerical Investigation on Weld-Induced Imperfections in Aluminum Ship Plates
Authors: Chen Bai-Qiao , Guedes Soares C.
Published: May 2019

The present work aims at better understanding and predicting the thermal and structural responses of aluminum components subjected to welding, contributing to the design and fabrication of aluminum ships such as catamarans, lifesaving boats, tourist ships, and fast ships used in transportation or in military applications. Taken into consideration the moving heat source in metal inert gas (MIG) welding, finite element models of plates made of aluminum alloy are established and validated against published experimental results. Considering the temperature-dependent thermal and mechanical properties of the aluminum alloy, thermo-elasto-plastic finite element analyses are performed to determine the size of the heat-affected zone (HAZ), the temperature histories, the distortions, and the distributions of residual stresses induced by the welding process. The effects of the material properties on the finite element analyses are discussed, and a simplified model is proposed to represent the material properties based on their values at room temperature.
Investigation of Structural Conformity in a Three-Pad Adaptive Air Foil Bearing With Regard to Active Control of Radial Clearance
Authors: Sadri Hossein , Schlums Henning , Sinapius Michael
Published: May 2019

Various solutions for the design of oil-free bearings are discussed in the literature. Adding hydrodynamic preload to the foil bearings by profiling the inner bore of the bearing is one of the most frequently investigated methods for improving the bearing stability and damping character of the entire system. However, this approach leads to a reduced load capacity and thus to an increased lift-off speed of the foil bearings. Observations of this kind lead to the presentation of various solutions for active bearing contour adjustment, which benefits from different profiles of the lubricant film. Most of these concepts use piezoelectric stack actuators to generate the required alternating force, although the influence of the stiffness of adaptive elements on bearing performance is not fully discussed in the literature. The focus of this study is on the investigation of structural conformity, i.e., the harmonization of stiffness with respect to the requirements for shape control and load capacity of an adaptive air foil bearing (AAFB). The result may be a basis for the consideration of additional degrees of freedom in any concept with shape control as the main design framework in interaction between the lubricant and compliant structure in an air foil bearing from both static and dynamic points of view.
EPS Conceptual Design for GoM Deepwater Fields
Authors: Choi Michael , Kilner Andrew , Marcollo Hayden , Withall Tim , Carra Chris , Huang Kevin
Published: May 2019

To avoid making billion dollar mistakes, operators with discoveries in deepwater (∼3,000m) Gulf of Mexico (GoM) need dependable well performance, reservoir response and fluid data to guide full-field development decisions. Recognizing this need, the DeepStar consortium developed a conceptual design for an Early Production System (EPS) that will serve as a mobile well test system that is safe, environmentally friendly and cost-effective.

The EPS is a dynamically positioned (DP) Floating, Production, Storage and Offloading (FPSO) vessel with a bundled top tensioned riser having quick emergency disconnect capability. Both oil and gas are processed onboard and exported by shuttle tankers to local markets. Oil is stored and offloaded using standard FPSO techniques, while the gas is exported as Compressed Natural Gas (CNG).

This paper summarizes the technologies, regulatory acceptance, and business model that will make the DeepStar EPS a reality.

Paper published with permission.
ISTD Implementation and Service-Life Monitoring
Authors: Palmer Glen
Published: May 2019

Subsection ISTD of ASME’s Operation and Maintenance of Nuclear Power Plants (OM Code) is the required code for preservice and inservice examination and testing of dynamic restraints (snubbers). This code replaced the inspection requirements of Article IWF-5000, “Inservice Inspection Requirements for Snubbers,” in Section XI, “Inservice Inspection of Nuclear Power Plant Components,” of the ASME Boiler and Pressure Vessel Code after the publication of the 2006 addenda to Section XI, which deleted Article IWF-5000. When the requirements of IWF-5000 were deleted, the requirements for examination and testing of snubbers, as required by Section 50.55a, “Codes and Standards,” of Title 10, “Energy,” of the Code of Federal Regulations (10 CFR 50.55a) became those specified by Subsection ISTD of the ASME OM Code. Therefore, when nuclear power plant owners prepare their ten-year inservice testing (IST)/inservice inspection (ISI) program updates that incorporate the 2006 (or later) addenda to Section XI, the snubber requirements will be required to be in accordance with those of Subsection ISTD of the latest approved edition and addenda of the ASME OM Code (2004 Edition with Addenda through 2006). This edition of the ASME OM Code is cited in the NRC Rulemaking which was published on June 21, 2011.

Because this is a change in requirements, owners should be asking some of the following questions: What is the difference between our existing program requirements and those included in Subsection ISTD of the ASME OM Code? How will this change our existing program or the way the current snubber examination and testing program is implemented? How much effort will be required to implement this program change? This paper will provide some specific guidance for the implementation of the ISTD Code and will identify typical areas where changes may be required to existing snubber examination and testing programs. It will also describe some approaches to satisfy the requirements of ISTD-6000, “Service Life Monitoring,” which might not have been included in the previous requirements under Section XI.

Paper published with permission.
Resistivity and surface scattering of (0001) single crystal ruthenium thin films
Authors: Ezzat Sameer S. , Mani Prabhu Doss , Khaniya Asim , Kaden William , Gall Daniel , Barmak Katayun , Coffey Kevin R.
Published: May 2019

The resistivity size effect in nanoscale metals is of both scientific and technological interest, the latter due to its importance to interconnects between transistors in integrated circuits. In this work, the authors report the variation of resistivity with film thickness and with changes in surface scattering of ex situ annealed single crystal Ru thin films grown on sapphire substrates by sputter deposition. The room temperature deposition of SiO2 on the Ru sample surface was observed to increase the resistivity of films that had previously been subjected to annealing in a reducing gas ambient. These overcoated samples were also found to increase in resistivity as a result of an oxidizing anneal and reduce in resistivity as a result of a subsequent reducing gas (Ar + H2) anneal. To a large extent, the surface structure and electron scattering characteristics were found to be reversible between oxidizing and reducing gas anneals. The chemistry and structure of the Ru upper surface was characterized by low energy electron diffraction (prior to the SiO2 overcoat deposition), x-ray reflectivity, x-ray photoelectron spectroscopy, and resistivity measurements. The changes in surface structure and chemistry were related to the changes in the specularity of the Ru surface for electron scattering in the context of the Fuchs–Sondheimer semiclassical model of the resistivity size effect, and in this context a mostly specular metal/dielectric interface is reported.
The difference between first and second harmonic amplitudes correlates between glottal airflow and neck-surface accelerometer signals during phonation
Authors: Mehta Daryush D. , Espinoza Víctor M. , Van Stan Jarrad H. , Zañartu Matías , Hillman Robert E.
Published: May 2019

Miniature high-bandwidth accelerometers on the anterior neck surface are used in laboratory and ambulatory settings to obtain vocal function measures. This study compared the widely applied L1–L2 measure (historically, H1–H2)—the difference between the log-magnitude of the first and second harmonics—computed from the glottal airflow waveform with L1–L2 derived from the raw neck-surface acceleration signal in 79 vocally healthy female speakers. Results showed a significant correlation (r = 0.72) between L1–L2 values estimated from both airflow and accelerometer signals, suggesting that raw accelerometer-based estimates of L1–L2 may be interpreted as reflecting glottal physiological parameters and voice quality attributes during phonation.
Identifying a creak probability threshold for an irregular pitch period detection algorithm
Authors: Murton Olivia , Shattuck-Hufnagel Stefanie , Choi Jeung-Yoon , Mehta Daryush D.
Published: May 2019

Irregular pitch periods (IPPs) are associated with grammatically, pragmatically, and clinically significant types of nonmodal phonation, but are challenging to identify. Automatic detection of IPPs is desirable because accurately hand-identifying IPPs is time-consuming and requires training. The authors evaluated an algorithm developed for creaky voice analysis to automatically identify IPPs in recordings of American English conversational speech. To determine a perceptually relevant threshold probability, frame-by-frame creak probabilities were compared to hand labels, yielding a threshold of approximately 0.02. These results indicate a generally good agreement between hand-labeled IPPs and automatic detection, calling for future work investigating effects of linguistic and prosodic context.
Toward principled regularization of deep networks—From weight decay to feature contraction
Authors: Maki Atsuto
Published: May 2019

Deep networks for classification problems may be enhanced by training with proper regularization exploiting intrinsic class similarities.
CuRBing cancer’s enthusiasm
Authors: Sowalsky Adam G.
Published: May 2019

A gene expression signature of biallelic
RB1
loss identifies more aggressive tumors.
Prevalence and distribution of HPV types in genital warts in Xi’an, China: a prospective study
Authors: Zhu Cansheng , Wang Yaofei , Mao Weihua , Zhang Hongshan , Ma Jiaju
Published: May 2019

Objectives

To characterise the prevalence and distribution of human papillomavirus (HPV) types in genital warts in Xi’an, China.

Methods

This prospective study was conducted in Shaanxi Provincial Institute for Skin Disease and STD Control (SPISSC) between September 2014 and April 2017. Genital wart samples were obtained from 879 patients, including 512 men and 367 women. HPV genotyping was performed by using an automatic nucleic acid hybridisation system.

Results

Of the 879 patients with genital warts, the detectable rates of low-risk, high-risk and total HPV types were 45.4%, 34.5% and 57.8%, respectively. The detectable rate of low-risk HPV types (45.4%) was significantly higher than that of high-risk HPV types (34.5%) (χ2=21.85, p<0.01). The detectable rate of low-risk HPV types of men (52.3%) was significantly higher than that of women (35.7%) (χ2=23.90, p<0.01). The detectable rates of one HPV type infection and two and three or more HPV type coinfections were 26.1%, 17.5% and 14.2%, respectively. HPV6 (24.9%), HPV11 (17.9%), HPV52 (9.9%) and HPV16 (7.3%) were the four most common HPV types.

Conclusions

The results of this study suggest that low-risk HPV types are major pathogens of genital warts, but high-risk HPV type infections and multiple HPV type coinfections are also common in genital warts. HPV6, 11, 52 and 16 are the four most common HPV types in genital wart in Xi’an, China.
Implementation of clean cookstove interventions and its effects on blood pressure in low-income and middle-income countries: systematic review
Authors: Onakomaiya Deborah , Gyamfi Joyce , Iwelunmor Juliet , Opeyemi Jumoke , Oluwasanmi Mofetoluwa , Obiezu-Umeh Chisom , Dalton Milena , Nwaozuru Ucheoma , Ojo Temitope , Vieira Dorice , Ogedegbe Gbenga , Olopade Christopher
Published: May 2019

Objective

A review of the implementation outcomes of clean cookstove use, and its effects on blood pressure (BP) in low-income and middle-income countries (LMICs).

Design

Systematic review of studies that reported the effect of clean cookstove use on BP among women, and implementation science outcomes in LMICs.

Data sources

We searched PubMed, Embase, INSPEC, Scielo, Cochrane Library, Global Health and Web of Science PLUS. We conducted searches in November 2017 with a repeat in May 2018. We did not restrict article publication date.

Eligibility criteria for selecting studies

We included only studies conducted in LMICs, published in English, regardless of publication year and studies that examined the use of improved or clean cookstove intervention on BP. Two authors independently screened journal article titles, abstracts and full-text articles to identify those that included the following search terms: high BP, hypertension and or household air pollution, LMICs, cookstove and implementation outcomes.

Results

Of the 461 non-duplicate articles identified, three randomised controlled trials (RCTs) (in Nigeria, Guatemala and Ghana) and two studies of pre–post design (in Bolivia and Nicaragua) met eligibility criteria. These articles evaluated the effect of cookstove use on BP in women. Two of the three RCTs reported a mean reduction in diastolic BP of −2.8 mm Hg (−5.0, –0.6; p=0.01) for the Nigerian study; −3.0 mm Hg; (−5.7, –0.4; p=0.02) for the Guatemalan study; while the study conducted in Ghana reported a non-significant change in BP. The pre–post studies reported a significant reduction in mean systolic BP of −5.5 mm Hg; (p=0.01) for the Bolivian study, and −5.9 mm Hg (−11.3, –0.4; p=0.05) for the Nicaraguan study. Implementation science outcomes were reported in all five studies (three reported feasibility, one reported adoption and one reported feasibility and adoption of cookstove interventions).

Conclusion

Although this review demonstrated that there is limited evidence on the implementation of clean cookstove use in LMICs, the effects of clean cookstove on BP were significant for both systolic and diastolic BP among women. Future studies should consider standardised reporting of implementation outcomes.