bluuebunny/crossref_metadata_2025 huggingface dataset:
Responsiveness to priority‐based affirmative action policy in school choice
Authors: Dur Umut , Xie Yifan
Published: July 2022

We consider the priority‐based affirmative action policy in school choice. We weaken the responsiveness to affirmative action policy by requiring at least one minority student to be weakly better off when their priorities are improved. We find that under both the student‐proposing deferred acceptance mechanism and the top trading cycles mechanism at least one minority student becomes weakly better off when their priorities are improved. We also strengthen the responsiveness to affirmative action policy by requiring all minority students to be weakly better off when their priorities are improved. We call this property strict responsiveness to affirmative action policy. We find that there is no nonwasteful, individually rational, mutually best, and strategy‐proof mechanism that is strictly responsive to affirmative action policy. We then find a sufficient condition for the affirmative action policy to satisfy for the student‐proposing deferred acceptance mechanism to be strictly responsive to affirmative action policy by setting restrictions on the priority improvements made by the policy.
Structure‐aware dehazing of sewer inspection images based on monocular depth cues
Authors: Xia Zixia , Guo Shuai , Sun Di , Lv Yaozhi , Li Honglie , Pan Gang
Published: August 2022

In sewer pipes, haze caused by the humid environment seriously impairs the quality of closed‐circuit television (CCTV) images, which leads to poor performance of subsequent pipe defects detection. Meanwhile, the complexity of sewer images, such as steep depth change and extensive textureless regions, brings great challenges to the performance or application of general dehazing algorithms. Therefore, this study estimates sewer depth maps first with the help of the water–pipewall borderlines to produce the paired dehazing dataset. Then a structure‐aware nonlocal network (SANL‐Net) is proposed with the detected borderlines and the dehazing result as two supervisory signals. SANL‐Net shows its superiority over other state‐of‐the‐art approaches with 147 in mean square error (MSE), 27.28 in peak signal to noise ratio (PSNR), 0.8963 in structural similarity index measure (SSIM), and 15.47M in parameters. Also, the outstanding performance in real image dehazing implies the accuracy of depth estimation. Experimental results indicate that SANL‐Net significantly improves the performance of defects detection tasks, such as an increase of 23.16% in mean intersection over union (mIoU) for semantic segmentation.
The SPTLC1 p.S331 mutation bridges sensory neuropathy and motor neuron disease and has implications for treatment
Authors: Fiorillo Chiara , Capodivento Giovanna , Geroldi Alessandro , Tozza Stefano , Moroni Isabella , Mohassel Payam , Cataldi Matteo , Campana Chiara , Morando Simone , Panicucci Chiara , Pedemonte Marina , Brolatti Noemi , Siliquini Sabrina , Traverso Monica , Baratto Serena , Debellis Doriana , Magri Stefania , Prada Valeria , Bellone Emilia , Salpietro Vincenzo , Donkervoort Sandra , Gable Kenneth , Gupta Sita D. , Dunn Teresa M. , Bönnemann Carsten G. , Taroni Franco , Bruno Claudio , Schenone Angelo , Mandich Paola , Nobbio Lucilla , Nolano Maria
Published: July 2022

Aims

SPTLC1‐related disorder is a late onset sensory‐autonomic neuropathy associated with perturbed sphingolipid homeostasis which can be improved by supplementation with the serine palmitoyl‐CoA transferase (SPT) substrate, l‐serine. Recently, a juvenile form of motor neuron disease has been linked to SPTLC1 variants. Variants affecting the p.S331 residue of SPTLC1 cause a distinct phenotype, whose pathogenic basis has not been established. This study aims to define the neuropathological and biochemical consequences of the SPTLC1 p.S331 variant, and test response to l‐serine in this specific genotype.

Methods

We report clinical and neurophysiological characterisation of two unrelated children carrying distinct p.S331 SPTLC1 variants. The neuropathology was investigated by analysis of sural nerve and skin innervation. To clarify the biochemical consequences of the p.S331 variant, we performed sphingolipidomic profiling of serum and skin fibroblasts. We also tested the effect of l‐serine supplementation in skin fibroblasts of patients with p.S331 mutations.

Results

In both patients, we recognised an early onset phenotype with prevalent progressive motor neuron disease. Neuropathology showed severe damage to the sensory and autonomic systems. Sphingolipidomic analysis showed the coexistence of neurotoxic deoxy‐sphingolipids with an excess of canonical products of the SPT enzyme. l‐serine supplementation in patient fibroblasts reduced production of toxic 1‐deoxysphingolipids but further increased the overproduction of sphingolipids.

Conclusions

Our findings suggest that p.S331 SPTLC1 variants lead to an overlap phenotype combining features of sensory and motor neuropathies, thus proposing a continuum in the spectrum of SPTLC1‐related disorders. l‐serine supplementation in these patients may be detrimental.
Leadless pacemakers as a new alternative for pacemaker lead‐related superior vena cava syndrome: A case report
Authors: Curnis Antonio , Milidoni Antonino , Arabia Gianmarco , Bontempi Luca , Cerini Manuel , Salghetti Francesca , Ahmed Ashraf , Ferraresi Roberto , Mitacchione Gianfranco , Mascioli Giosuè
Published: August 2022

Superior vena cava (SVC) syndrome is a rare disease induced by thrombosis and consequent occlusion of SVC, negatively affecting morbidity and mortality. The incidence of SVC syndrome from central venous catheters and pacemaker or defibrillator leads is increasing. Optimal treatment of pacemaker or defibrillator‐related SVC syndrome is not well defined. Lead extraction causes mechanical trauma to the vessel wall. In addition, subsequent device implantation on the contralateral side can be an added factor for venous occlusion. The use of leadless pacemakers could be an interesting option to reduce the risk of SVC restenosis after lead extraction. We report a clinical case of PM leads‐related SVC syndrome referred to our centers and treated with transvenous lead extraction, leadless pacemaker implantation and subsequent percutaneous angioplasty and stenting of the SVC and left innominate vein.
Gardenia carotenoid cleavage dioxygenase 4a is an efficient tool for biotechnological production of crocins in green and non‐green plant tissues
Authors: Zheng Xiongjie , Mi Jianing , Balakrishna Aparna , Liew Kit Xi , Ablazov Abdugaffor , Sougrat Rachid , Al‐Babili Salim
Published: July 2022

Crocins are beneficial antioxidants and potential chemotherapeutics that give raise, together with picrocrocin, to the colour and taste of saffron, the most expensive spice, respectively. Crocins are formed from crocetin dialdehyde that is produced in Crocus sativus from zeaxanthin by the carotenoid cleavage dioxygenase 2L (CsCCD2L), while GjCCD4a from Gardenia jasminoides, another major source of crocins, converted different carotenoids, including zeaxanthin, into crocetin dialdehyde in bacterio. To establish a biotechnological platform for sustainable production of crocins, we investigated the enzymatic activity of GjCCD4a, in comparison with CsCCD2L, in citrus callus engineered by Agrobacterium‐mediated supertransformation of multi genes and in transiently transformed Nicotiana benthamiana leaves. We demonstrate that co‐expression of GjCCD4a with phytoene synthase and β‐carotene hydroxylase genes is an optimal combination for heterologous production of crocetin, crocins and picrocrocin in citrus callus. By profiling apocarotenoids and using in vitro assays, we show that GjCCD4a cleaved β‐carotene, in planta, and produced crocetin dialdehyde via C30 β‐apocarotenoid intermediate. GjCCD4a also cleaved C27 β‐apocarotenoids, providing a new route for C17‐dialdehyde biosynthesis. Callus lines overexpressing GjCCD4a contained higher number of plastoglobuli in chromoplast‐like plastids and increased contents in phytoene, C17:0 fatty acid (FA), and C18:1 cis‐9 and C22:0 FA esters. GjCCD4a showed a wider substrate specificity and higher efficiency in Nicotiana leaves, leading to the accumulation of up to 1.6 mg/g dry weight crocins. In summary, we established a system for investigating CCD enzymatic activity in planta and an efficient biotechnological platform for crocins production in green and non‐green crop tissues/organs.
Patient and caregiver perspectives on delayed childhood Gorlin syndrome diagnoses
Authors: Neale Holly , Breneiser Julie A. , Hawryluk Elena B.
Published: August 2022

The diagnostic trends of Gorlin syndrome (GS) in the pediatric population are not well understood. In an international survey conducted by the Gorlin Syndrome Alliance, 118 individuals who were diagnosed with GS when aged 18 years and under provided information about their diagnosis. Oral surgeons and dermatologists were the most commonly reported physicians involved in diagnosis for 48.3% and 28% of cases, respectively. For 50% of children, the diagnosis was made within a year from presenting sign(s), while 27% report over 4 years to receive GS diagnosis. Of individuals who reported >4 years between presenting signs and diagnosis, 81.3% attributed the delay to insufficient medical team knowledge and 65.6% attributed to lack of personal awareness that presenting signs were related to GS, emphasizing the need for patient and physician education of GS for prompt diagnosis.
Kynurenine metabolism is altered in mdx mice: a potential muscle to brain connection
Authors: Copeland Emily N. , Watson Colton J. F. , Whitley Kennedy C. , Baranowski Bradley J. , Kurgan Nigel , MacNeil Adam J. , MacPherson Rebecca E. K. , Fajardo Val A. , Allison David J.
Published: August 2022

New Findings

What is the central question in this study?

Promoting muscle health with regular aerobic exercise can improve mental health through a kynurenine metabolic pathway: do conditions of muscle disease such as muscular dystrophy negatively influence this pathway?

What is the main finding and its importance?

The DBA/2J mdx model of Duchenne muscular dystrophy exhibits altered kynurenine metabolism with less kynurenic acid and peroxisome proliferator‐activated receptor‐γ coactivator 1‐α and higher levels of tumour necrosis factor α mRNA – results associated with anxiety‐like behaviour.

Regular exercise can direct muscle kynurenine (KYN) metabolism toward the neuroprotective branch of the kynurenine pathway thereby limiting the accumulation of neurotoxic metabolites in the brain and contributing to mental resilience. However, the effect of muscle disease on KYN metabolism has not yet been investigated. Previous work has highlighted anxiety‐like behaviours in approximately 25% of patients with Duchenne muscular dystrophy (DMD), possibly due to altered KYN metabolism. Here, we characterized KYN metabolism in mdx mouse models of DMD. Young (8–10 week old) DBA/2J (D2) mdx mice, but not age‐matched C57BL/10 (C57) mdx mice, had lower levels of circulating kynurenic acid (KYNA) and lower KYNA:KYN ratio compared with their respective wild‐type (WT) controls. While both C57 and D2 mdx mice displayed signs of anxiety‐like behaviour, spending more time in the corners of the arena during a novel object recognition test, this effect was more prominent in D2 mdx mice. Correlational analysis detected a significant negative association between KYNA:KYN levels and time spent in corners in D2 mice, but not C57 mice. In extensor digitorum longus muscles from D2 mdx mice, but not C57 mdx mice, we found lowered protein levels of peroxisome proliferator‐activated receptor‐γ coactivator 1‐α and kynurenine amino transferase‐1 enzyme when compared with WT. Furthermore, D2 mdx quadriceps muscles had the highest level of tumour necrosis factor α expression, which is suggestive of enhanced inflammation. Thus, our pilot work shows that KYN metabolism is altered in D2 mdx mice, with a potential contribution from altered muscle health.
NACA Sonic-Flow-Orifice Temperature Probe in High-Gas-Temperature Measurement
Authors: Blackshear P. L.
Published: July 2022

A brief discussion of the problem of measuring temperatures in jet engines is given. A method of measuring these temperatures by pneumatic means is described. This method involves the use of two sonic-flow orifices in series to give, through thermodynamic calculations, the total temperature of the gas entering the first orifice. An evaluation of this method is given including a discussion of the sampling error in nonhomogeneous gases, and an experimental comparison against a thermocouple and the sodium D-line reversal method is made showing favorable agreement. Results of applying this method of measuring temperature in full-scale engines are discussed.
Relative Abrasiveness of the Cast Surfaces of Various Gray-Iron Castings on Single-Point Tools of High-Speed Steel
Authors: Datsko Joseph , Boston O. W.
Published: July 2022

This study reveals that plain gray-iron castings made in sand molds have a very abrasive surface that results in a low tool life when machining the surface. This condition can be eliminated almost completely by pickling the castings prior to machining. Annealing improves the machinability of the casting, but it also results in a more pronounced “skin effect.” By means of an annealing and pickling treatment, the cutting speed for removing the surface was increased by 230 per cent.
Torsional Vibration Notes With Solutions for an Untuned Viscous Damper and Flexible Coupling With Nonlinear Elasticity
Authors: Porter F. P.
Published: July 2022

Several special relations are derived that may be used to simplify the solution of certain phases of the torsional vibration problem. A solution is described for the vibration of a system with an untuned viscous damper. Numerical values are given for the nonlinear elasticity of the Falk-Bibby type couplings. These values are rearranged into a form suitable for calculating undamped resonance curves of an engine installation which includes one of these couplings. An approximate solution for the resulting vibration is described and illustrated by calculation.
On the Solution of the Reynolds Equation for Slider-Bearing Lubrication—II: The Viscosity a Function of the Pressure
Authors: Charnes A. , Saibel E.
Published: July 2022

The solution of the Reynolds equation for slider-bearing lubrication is given for the finite bearing, side leakage included, when the viscosity is a known function of the pressure. The solution for the pressure distribution is obtained readily from the corresponding case of constant viscosity. The design factors—total load, center of pressure, friction force, and side leakage—also may be obtained, but, in general, the integrals involved must be worked out numerically. Qualitative properties of the pressure, total load, and center of pressure are obtained.
The Piston Gage as a Precise Pressure-Measuring Instrument
Authors: Johnson D. P. , Newhall D. H.
Published: July 2022

The errors which must be considered for accurate measurements of pressure with piston gages are discussed. A new design of piston gage is described which permits the operator to control the clearance between piston and cylinder at any operating pressure. Instrumental errors are thus substantially reduced, particularly those resulting from elastic distortion. A check list of errors inherent to piston gages is presented. These errors are to be considered when instruments are used to accuracies better than ½ of 1 per cent. The need for a check on the longtime variations of the piston gage is supplied by the fixed points, changes of state of some very pure materials which take place at definite pressures. Such are the melting pressure of solid mercury at 0 C, the melting pressure of water at 30 C, the transition between crystalline states of bismuth. As an indication of its possibilities the experimental model of the controlled-clearance piston gage was used to measure the melting point of mercury at 0 C. Results were in satisfactory agreement with Bridgman’s value.
Techniques and Equipment for Generation of Dynamic High Pressures
Authors: Mickevicz E. J.
Published: July 2022

An apparatus has been developed at the Naval Ordnance Laboratory which will reproduce characteristic pressure-time pulses, simulating ballistic pressures, for use in the design and evaluation of ordnance. Details of the apparatus and results obtained are given.
Influence of Residual Stress on Behavior of Thick-Wall Closed-End Cylinders
Authors: Faupel J. H. , Furbeck A. R.
Published: July 2022

Results obtained from macro residual - stress tests, internal-pressure tests, and mechanical property tests on Cr-Ni-Mo-V steel, SAE 3320, SAE 4340, and SAE 1045 steel cylinders are presented. The presence of macro residual stresses appears to influence only initial yielding at the bore of cylinders; the effect of this residual stress can be allowed for in the formula used to predict the internal pressure at initial yielding at the bore. Methods also are presented for predicting, approximately, the internal pressures at full wall yielding (overstrain) and bursting. Finally a method is suggested for predicting the pressure-strain curve for heavy-wall cylinders from an analysis of tensile-test data.
Static-Dynamic Load Machine for High Pressure
Authors: Fleischhauer E. T. , Dorsey E. G.
Published: July 2022

During the course of a particular machine-design program it was found that experimental difficulties with fluid seals and impact loads were hindering the proper solution of the design problem. There was a clear need for auxiliary apparatus which would permit systematic exploration of fixed-point fluid seals, moving fluid seals, and impact loads created by arrestation of rapidly moving machine elements. The “static-dynamic load machine,” that is presently employed in an investigation of all three problems, is described in the paper. The basic design configuration of this machine was determined by the required accessibility of the test devices and the method employed for rapid load delivery.
Some Investigations With Wet Compression
Authors: Hamrick J. T. , Beede W. L.
Published: July 2022

This paper presents the results of some experimental investigations on several centrifugal-flow compressors using water injection. In addition, mechanical considerations, special instrumentation, and theoretical aspects are discussed and a method of computing adiabatic efficiency with wet compression is presented.
Transient and Steady-State Heat Transfer in Irradiated Citrus Fruit
Authors: Poppendiek H. F.
Published: July 2022

This paper presents an analytical study of the thermal structure within citrus fruits that are artificially heated by radiant orchard heaters; this analysis may be utilized to establish more firmly orchard heating-design criteria. Transient and steady-state temperature solutions are derived for an ideal heat-transfer system consisting of a homogeneous sphere which suddenly receives radiant energy from a point source and loses energy by convection and reradiation to the surroundings. These solutions are compared to a set of experimental temperature measurements within an orange which was transiently irradiated in an orchard.
Operation of Sunbury Steam-Electric Station Using Pulverized-Anthracite Fuel
Authors: Richards T. B.
Published: July 2022

The largest deposits of anthracite in the United States are located in north and central eastern Pennsylvania. Only a few central stations burn this type of fuel, and prior to World War II those stations able economically to justify its use, were relatively small in size. Pennsylvania Power & Light Company, whose service area includes a large segment of the anthracite region, is a pioneer in the burning of anthracite and is the largest single consumer of this fuel in the United States, having burned 2,325,500 net tons in 1951. During 1949 this company completed the installation of four 400,000 lb per hr steam generators at Sunbury Steam Electric Station located between Shamokin Dam and Hummels Wharf on the Susquehanna River near Sunbury, Pa. This paper presents the design features peculiar to the handling, pulverizing, and burning of anthracite, as well as some of the problems encountered during the first 3 years of operation. Reference is also made to a third unit, placed in service in 1951, which burns a mixture of anthracite and bituminous coal and a fourth unit, in the process of construction, which will employ the reheat cycle and also will burn an anthracite-bituminous coal mixture.
An Investigation of Heat Transfer From an Inclined Flat Plate in Free Convection
Authors: Rich B. R.
Published: July 2022

The differential equations for heat transfer from vertical plates in free convection were rederived in dimensionless form and extended to include inclined plates. The analysis indicated that the only change in the plate was the component of the gravitational force in the plate surface direction. The limitation of the equation is that the flow be laminar and two-dimensional. Heat transfer from a flat plate in free convection was studied at angles of inclination ranging from 0 to 40 deg measured from the vertical, for a range of Grashof numbers from 106 to 109 and temperature differences from the surface to the surroundings of 200 to 260 F. The investigation shows the inclined-plate nondimensional unit thermal conductance, Nu, can be predicted from vertical plate conductances. The Grashof number in the Nusselt relation for the vertical plate, when modified by the cosine of the angle of inclination, can predict the inclined-plate conductances to within 10 per cent of those determined experimentally.
Design of a Square-Root-Extracting, Force-Balance, Pneumatic Transmitter, Including Derivation of Formulas
Authors: Goldberg Arnold
Published: July 2022

This paper describes the design of a device for measuring fluid flow in a pipe. It deals with a particular type of flowmeter, one that measures the differential pressure developed across an orifice or other primary element and puts out an air pressure directly proportional to flow rate. Square root must be extracted in such an instrument. The square-root-extracting part of the device is of the shaped displacer and mercury type, in which the displacer does not move. Formulas are derived for calculating the shape.
A Method of Obtaining Shear Stress-Strain Graphs by Interpretation of Moment-Twist Data
Authors: Kaar P. H.
Published: July 2022

Many requests are made by industry for information from the Fritz Engineering Laboratory at Lehigh University. Among these was one from a manufacturer wishing to increase the strength of his industrial truck axles. The manufacturer was considering several different steels and wanted comparative strength data. The information was compiled by use of shear stress-strain curves. The method described here to obtain the shear stress-strain curves is not new, but is not often used. The procedure is simple to apply and merits the attention of others concerned with comparative strength and shear properties of axial round shafts.
Corrosion and Erosion in the Synthetic-Fuels Demonstration Plant
Authors: Gardner G. D. , Donovan J. T.
Published: July 2022

Corrosion and erosion during 2 years of intermittent operation of the first American coal-hydrogenation plant are described as well as solutions and improvements developed. Isolated cases of localized corrosion fatigue, caustic embrittlement, and pitting are described. Proper alloy-steel selection has minimized the effect of hydrogen attack in high-pressure equipment except where design temperature has been exceeded. High-pressure lines and valves handling oil-solid mixtures containing absorbed gases have evidenced greatest erosion rates.
Hydraulic Problems Encountered in Intake Structures of Vertical Wet-Pit Pumps and Methods Leading to Their Solution
Authors: Fraser W. H.
Published: July 2022

The design of intake channels and tunnels for the efficient operation of wet-pit pumps is considered. Basically the problem is that of determining the flow pattern and losses in the suction intake and predicting their combined effect on the pump performance. Because of long distances, obstructions, and diversions, faulty flow often occurs. The resulting difficulties are explained and the methods employed in solving the attendant problems are outlined.
Air-Preheater Design as Affected by Fuel Characteristics
Authors: Karlsson Hilmer , Hammond W. E.
Published: July 2022

The fuel characteristic that appears to control plugging and corrosion in air preheaters is sulphur content. While other fuel constituents contribute to the degree of the problem, their effectiveness depends upon the sulphur content. The presence of carbon in the fuel gas may aggravate the corrosion problem so that the best combustion conditions must be maintained carefully. In selecting air heaters for new installations, it is not possible to predict with any certainty the type of fuel that will be available during the life of the application; consequently, the air-heater design must provide controls that will maintain the cold-end temperatures within safe limits. The use of Cor-Ten or Mayari-R for the low-temperature surface and the use of cold-end baskets is recommended. Application of effective soot blowers using superheated steam or dry compressed air permits control of deposit formation. In the event that circumstances result in serious deposit formation, provision for water-washing of the heaters will provide an effective remedy. Consistent attention must be given to cold-end temperature under all conditions of operation and in this respect automatic controls should be considered.
The Motion of a Link Chain Over a Roller
Authors: de Jonge A. E. Richard
Published: July 2022

A coal-cutting excavator is described in which trouble was encountered with link chains carrying excavating buckets. The chains were moved by an upper hexagon tumbler driven by an electric motor. The trouble was traced to the link chains passing over too small a deflecting roller. An investigation into the geometry of the problem is presented and it is shown that the mechanical three or multibody problem can be reduced to a problem in kinematic geometry by eliminating the forces, but retaining their lines of action. A solution for this problem is given. The principal object, namely, the derivation of the correct dimension for the deflecting roller to prevent the troublesome condition that existed, has been solved.
A Practical Solution of a Three-Dimensional Flow Problem of Axial-Flow Turbomachinery
Authors: Smith L. H. , Traugott S. C. , Wislicenus G. F.
Published: July 2022

During the past decade three-dimensional flow problems of turbomachinery have been solved for frictionless fluids under the assumption of an infinite number of vanes. However, the practical application of this advancement to the design of turbomachinery has not yet reached a state of acceptance commensurate with the practical importance of this theoretical development. The present paper endeavors to contribute toward such application by presenting the principles of the theory in a physically simple manner, and by illustrating its application by two examples, solving the general problem by two successive approximations. The first approximation disregards the departures of the meridional streamlines from their straight and parallel potential-flow pattern; the second approximation takes account of these departures on the basis of the first. The vorticity of the flow is assumed to be strong. The time and means required for working out each of the examples were found to fall within the practical limits of a competently staffed engineering department.
Complete Characteristic Circle Diagrams for Turbomachinery
Authors: Swanson W. M.
Published: July 2022

The experimental test results for operating a hydraulic turbomachine in every possible manner (noncavitating) are presented for a representative single-stage axial-flow and mixed-flow pump. A comparison is made among the three basic types of machine, axial, radial, and mixed flow. A new method for representing, on a single diagram, the efficiencies in all types of operation is proposed and demonstrated for the case of these three pumps. A method for predicting the complete characteristics from ideal flow considerations is given.
A Fast-Response True-Mass-Rate Flowmeter
Authors: Li Yao Tzu , Lee Shih-Ying
Published: July 2022

A flowmeter capable of measuring directly the true rate of mass flow would have many industrial applications and would eliminate many of the shortcomings of instruments now available for flow measurements. A description and diagrams are presented of a new type of mass-rate flowmeter with a long range, a linear scale, and a very fast response.
Workpiece and Surface Temperatures in Milling
Authors: Schmidt A. O.
Published: July 2022

The temperature gradient in a workpiece while being milled and the existence of very high instantaneous surface temperatures during the cut have been determined experimentally. It has been proved in many tests and often can be observed visually that tool tips frequently fail because of the very high temperatures attained near the cutting edge.
The Pitot-Venturi Flow Element Water Service Report
Authors: Stoll H. W.
Published: July 2022

The first paper by the author presented in detail the design characteristics of the pitot-venturi flow element and how they are influenced by air flow. Tests clearly show that liquid-flow performance cannot be predicted from air-flow runs and, instead, actual liquid-flow conditions are required to establish a dependable relationship between velocity and differential produced. The test setup and the instrumentation needs are described. Four-inch and six-inch pipe were used and the performance curves for these are discussed. Flow equations are included and a brief analysis of them is given.
Experiments With Water-Lubricated Tapered-Land Thrust Bearings
Authors: Levinsohn Maurice , Reynolds N. E.
Published: July 2022

Experiments were made to determine the load-carrying ability of water-lubricated, tapered-land, carbon thrust bearings. Nine different bearings having various combinations of radial and circumferential tapers were tested. As was expected, the degree of taper had a profound effect on performance of those bearings tested. One design was able to carry a load of 110 psi (present load limit of test machine) at speeds of 860, 1725, and 3450 rpm. The lubricant used in this test was distilled water. The range of its viscosity was from 0.72 to 0.96 centipoises.
On the Validity of Assumptions Made in Theories of Plastic Flow for Metals
Authors: Marin Joseph , Hu L. W.
Published: July 2022

The purpose of this paper is to report the results of a series of special biaxial-stress tests made to check the validity of certain assumptions used in theory of plasticity. In these tests the stresses produced were tensile biaxial stresses introduced in a tubular specimen by applying an internal pressure and axial tension. The stresses produced were in the plastic range and the material tested was a hot-rolled aluminum alloy designated as 14S-T6. A test to determine the validity of the distortion-energy criterion, used in formulating the plastic stress-strain relations by the flow theory, showed that the test results did not support this assumption. Special tests were made to determine whether plastic-deformation requirements as predicted by the slip theory were correct. In so far as these tests were concerned, the results supported the slip theory. Finally, tests were made to check the assumption of constancy of volume and constancy of incremental change in volume as required by the deformation and flow theories. These test results do not support the assumptions made in these theories relative to volume change.
Combustion of a Low-Volatility Fuel in a Turbojet Combustion Chamber—Effects of Fuel Vaporization
Authors: Holmes V. V. , Pahnke A. J. , Uyehara O. A. , Myers P. S.
Published: July 2022

Various degrees of vaporization of a typical diesel fuel were obtained by varying the temperature of the oil supplied to the turbojet combustion chamber. Experimental data showing the effect of fuel vaporization on combustion efficiency, flame length, and flame temperature, are presented as well as flame temperature-distance data for the combustion chamber.
An Investigation of the Burning Characteristics of Pulverized Cinders
Authors: Allen J. M.
Published: July 2022

A small laboratory furnace was used to determine the burning characteristics of pulverized locomotive cinders as a function of the residence time of the particles passing through the furnace. The independent effects of excess air, fineness of pulverization, furnace temperatures, and extent of preheat were studied. Results of these tests are useful in designing the equipment needed to burn the cinders in a locomotive firebox.
Quick-Starting of High-Pressure Boilers—Discussion: Quick-Starting of High-Temperature High-Pressure Boilers
Authors: Weismantle Arthur R.
Published: July 2022

Principles governing the quick-starting of steam generators are outlined. Superheater safety, drum safety, boiler expansion, and a general discussion of factors involved in quick starts are considered.
Metallurgy and Production of Suitable Aluminum-Alloy Ingots for Large Forgings and Extrusions
Authors: Fritzlen T. L.
Published: July 2022

The sizes of 14S, 24S, and 75S aluminum-alloy ingots needed for the United States Air Force large-press program are estimated and compared to the size of ingots cast in current production. The direct-chill process is selected for development of the casting of large ingots. Quality required, metallurgical factors involved, equipment used, and casting variables are discussed. Experimental results in casting 14S aluminum-alloy ingots weighing up to 12,000 lb are presented. An opinion is expressed on the future production of large aluminum-alloy ingots for use in extrusion and forging presses up to 25,000 and 50,000 tons capacity, respectively.
Stresses in a Pressure Vessel With a Conical Head
Authors: Watts G. W. , Lang H. A.
Published: July 2022

This paper presents the results of computations for determining the stresses in a pressure vessel with a conical head. The accurate bending theory of shells is used to evaluate the local bending stresses in the neighborhood of the junction of the conical head and the cylindrical body. Tables show the magnitudes of the shear stress, the circumferential stress, and the axial stress at the junction as multiples of pd/2t. For the axial and circumferential stresses, the tables show the magnitude and sense of the stress on both the internal and external surfaces of the vessel. Additional results show the magnitude and location of the maximum stress (of each of the three types) in the cylinder. Curves are given showing the maximum stresses for values of cone apex angle, ratio of conical head thickness to cylinder thickness, and ratio of cylinder diameter to cylinder thickness which will include most of the vessels encountered in practice.

Tables of influence numbers for the conical head are presented. These can be utilized in many problems which require attaching a conical shell to some other elastic structure. A discussion of the mathematical procedure is contained in an Appendix.
An Experimental Investigation of Over-Straining in Mild-Steel Thick-Walled Cylinders by Internal Fluid Pressure
Authors: Steele M. C. , Young John
Published: July 2022

The purpose of this paper is to study the mechanism of yielding and to compare with plastic theories strains observed at the bore and outside surfaces of mild-steel cylinders of 2:1 diameter ratio under internal fluid pressure. Observations disagree with theoretical assumptions concerning the progression of yielding; wedge regions of overstrained material, occupying a small fraction of the total volume, characterize the yielding process. Discrepancies with theory are observed in the measured strains. The fully plastic load-carrying capacities predicted from theory are higher than those observed in the experiments. Stability of deformation (creep) under maintained constant loads is discussed.
Dynamic Properties of Nodular Cast Iron—Part 1
Authors: Majors Harry
Published: July 2022

This paper presents the experimental results of an investigation on the mechanical properties of magnesium-treated nodular cast iron in the annealed and as-cast condition. The dynamic stress-concentration factors are compared with Neuber’s theoretical factors for hyperbolic notches, with Peterson’s results on steel, with Frocht’s photoelastic results, and with Grant’s data on flake cast iron and cerium-treated nodular iron. Fatigue results are shown for square and 45-deg V-shaped notches at speeds of 200 and 6000 rpm, as well as for various notch depths. The trend in size effect is indicated. Static damping capacities obtained from hysteresis loops in tension and compression are compared with torsional damping capacities and static damping capacities from bending.
Analysis of Stresses and Displacements in Heat-Exchanger Expansion Joints
Authors: Murphy Glenn
Published: July 2022

This paper presents a procedure for the analysis of stresses and displacements in an expansion joint, when the latter is assumed to be a surface of revolution. The analysis as presented employs a method of successive approximations, but, in general, the solution will be rapidly convergent. Possible thermal gradients in the joint are not included in the analysis as given, but may be introduced in the solution.
Strain-Hardening and Softening With Time in Reference to Creep and Relaxation in Metals
Authors: Nadai A.
Published: July 2022

Analytical expressions are formulated for describing the influence of strain-hardening, of the time rate of change of the flow resistance, and of recovery strains on the creep and relaxation of metals under uniaxial stress.
A Progress Report of Reheat Boiler Design and Operation
Authors: Vogel W. J. , Powell E. M.
Published: July 2022

A complete symposium on the reheat cycle was presented to the Society at the Annual Meeting in 1948. At that time, representatives of the various manufacturers of boilers and turbines reviewed the history of reheat and described in some detail the designs then being offered. A considerable number of these units have been placed in operation since then. The object of this paper is to discuss the performance of several of these new units and to describe some of the special features of operation.
The First Year’s Operation of the Dunkirk Steam Station
Authors: Ewart J. N.
Published: July 2022

The Dunkirk Steam Station went into commercial service on November 19, 1950, when the first unit was placed in regular operation. The second unit went into commercial operation on December 28 of the same year. The first year’s operation has not been without troubles which are likely to occur in breaking in a plant incorporating several new and untried developments. Nevertheless, its performance has been generally satisfactory. Operation of the reheat units has introduced no new limitation in flexibility nor increase in operating personnel over the non-reheat units, and the improved economy has more than justified its adoption.
The Development and Implementation of a Generation Program on the American Gas and Electric Company System: 3—200,000 Kw, 2000 Psi, 1050 F/1050 F—An Advance in the Economics of Integrated Power-System Generation
Authors: Sporn Philip , Fiala S. N.
Published: July 2022

This paper discusses the steam-electric generating units being installed at two new plants of the American Gas and Electric Company System, Kanawha River Plant of Appalachian Electric Power Company, and Muskingum River Plant of The Ohio Power Company. Reasons for the selection of unusually large single boiler-single turbine sets are presented in terms of the over-all generating requirements of the AG&E System. Basic considerations in the selection of component equipment for these units are developed, as well as the means by which these components have been combined to accomplish a very economical arrangement for mass generation of power for the System.
Thermodynamics of Gasification of Coal With Oxygen and Steam: Charts for Material and Enthalpy Balance Calculations
Authors: Edmister Wayne C. , Perry Harry , Corey R. C. , Elliott M. A.
Published: July 2022

Thermodynamic charts and tabulations are presented for calculating conveniently the heat balance, and product-gas yield and composition for the gasification of coal with oxygen and steam, on the assumption that water-gas shift equilibrium is attained by the product gases. These charts are of general applicability for any rank of coal; they cover a wide range of operating conditions through the use of multiple parameters, and may be used for pressures as high as 30 atm. Examples are given to illustrate the use and versatility of the charts. Charts and numerical examples are also given for a typical high-volatile C bituminous coal to illustrate the uses of such charts for a specific coal.
High-Speed Cascade Testing Techniques
Authors: Keast F. H.
Published: July 2022

This paper describes a cascade wind tunnel used by the author since 1948. Such auxiliary equipment as an automatic traverse and recording gear and a wedge-shaped probe are described. Some results are presented with a method of analysis for turbine cascades which converts the cascade results into a turbine-performance chart. The existence of a critical load factor results from this analysis.
Operating Characteristics of Cylindrical Roller Bearings at High Speeds
Authors: Macks E. F. , Nemeth Z. N. , Anderson W. J.
Published: July 2022

The significance of bearing operating temperature is discussed with regard to bearing operating limitations. The extent of the effects of various operating variables upon the bearing inner-race and outer-race temperatures is shown. Test-rig results as well as turbojet-engine data have been generalized by means of a cooling correlation analysis so that the designer may predict either the inner-race or the outer-race bearing temperature from a single curve, regardless of whether bearing speed, bearing load, oil flow, oil-inlet temperature, oil-inlet viscosity or oil-inlet velocity vary over wide ranges.
Measurement of Hydraulic-Turbine Vibration
Authors: Parmakian John , Jacobson R. S.
Published: July 2022

This paper describes a test program used to measure and eliminate the vibration which had produced extensive cracking in the blading of a slow-speed, 40,000-hp hydraulic turbine. Strains, accelerations, and pressures were measured at various locations on the turbine runner while the unit was in operation. The instruments used for these measurements were of the resistance type. Instrument signals were transmitted through collector rings and brushes to direct-writing oscillographs. The vibration was eliminated successfully by an inexpensive modification of the runner blading which is described in the paper.
Design of Flat-Wound Tension Springs
Authors: Conklin R. M. , Forry D. R.
Published: July 2022

The design of spring-actuated mechanisms often can be improved by the use of a flat-wound spring. Over-center snap-action and similar devices, where it is advantageous to keep the line of action of the spring as close to the bearings as possible, can be made appreciably more compact because of the narrow width of the spring. Equations for the deflection and stress of flat-wound springs are developed. A nomogram, which can be used to solve the stress and deflection equations simultaneously for square and round wire springs, is presented. Experimental results which support the theoretical analysis have been obtained and are discussed in detail.
High-Temperature Stress-Rupture Testing of Tubular Specimens
Authors: Kooistra L. F. , Blaser R. U. , Tucker J. T.
Published: July 2022

A large percentage of the high-temperature alloys is used in tubular form but most of the high-temperature strength data for these materials are based on simple tension bar specimens. Testing these materials in the shape and condition in which they are used eliminates many of the discrepancies between test specimen and actual service. A method has been developed in which a tubular specimen under internal steam pressure and at a controlled temperature is tested in stress rupture. This method closely simulates actual service conditions, except for the external flue-gas atmosphere and the temperature gradient through the tube wall existing in heat-transfer service. A suitable environment can, however, be provided when service conditions are known. The test apparatus is described and a number of the test results are discussed in relation to similar data obtained on simple tension specimens. Failures obtained under test conditions are compared with similar failures suffered by tubes in actual service.
Experimental Superheater for Steam at 2000 Psi and 1250 F—Progress Report of Field Operation
Authors: Ely F. G. , Eberle F.
Published: July 2022

To investigate the properties of new superstrength alloys for high-temperature steam superheater service a test element constructed of 2-in-OD alloy tubes was installed in an operating boiler at Twin Branch Plant and supplied with steam at 2000 psig 950 F, which was heated to 1250 F. Operating conditions, and results of the first 5000 service-hours are described in this paper. The test is being continued for thorough evaluation of the materials.
Wet Compression in an Axial-Flow Compressor
Authors: Soo Shao-Lee
Published: July 2022

The problem of wet compression in an axial-flow compressor was studied considering heat and mass transfer. The basic relation between the rate of compression, size of water particles, and over-all pressure ratio was obtained. The design criterion of an axial-flow compressor for wet compression was outlined. The possibility of introducing wet compression in a supersonic compressor was investigated as a two-phase Riemann shock problem.
A Method of Correlating Heat-Transfer Data for Surface Boiling of Liquids
Authors: Rohsenow W. M.
Published: July 2022

A method based on a logical explanation of the mechanism of heat transfer associated with the boiling process is presented for correlating heat-transfer data for nucleate boiling of liquids for the case of pool boiling. The suggested relation is clTxhfg=Csf(q/Aμlhfg(q/A)σg(ρl-ρv))0.33(clμlkl)1.7 where the various fluid properties are evaluated at the saturation temperature corresponding to the local pressure and Csf is a function of the particular heating surface-fluid combination.
Runaway Speed of Kaplan Turbines
Authors: Voaden G. H.
Published: July 2022

The object of this paper is to illustrate the type of laboratory test data which a turbine manufacturer must have to predict intelligently the runaway speed of a Kaplan turbine. The significant differences between the “on-cam” and “off-cam” runaway speeds are explained and data on actual runaway-speed tests conducted on a large Kaplan turbine installation are given. Attention is called to the possibility of reducing the runaway speed by restricting the minimum angle to which the runner blades can be pitched, and information is presented that will aid the purchaser of a Kaplan turbine to decide what runaway speed should be provided for in the generator.
Frequency-Response Analysis for Industrial Automatic-Control Systems
Authors: St. Clair D. W. , Coombs W. F. , Owens W. D.
Published: July 2022

The authors outline the fundamental principles of frequency-response analysis in terms familiar to the industrial automatic-control engineer, as well as present data obtained by frequency-response methods descriptive of the effect of typical variables on the behavior of the control system. These variables are gain, derivative time, reset rate, transportation lag, and capacity lag, with period of oscillation and stability as dependent variables. They have been combined to form three basic controllers and four basic processes, the data being presented for the various combinations of controller and process. The method of calculation and a specific example are given in the Appendix.