bluuebunny/crossref_metadata_2025 huggingface dataset:
Rationalising medical careers
Authors: Lydall Gregory J. , Bourke Julius H.
Published: July 2009

This article assesses the quality of higher psychiatric training opportunities under Modernising Medical Careers (MMC) and compares them with the existing specialist registrar (SpR) grade; the UK psychiatric educational literature is reviewed, and trainee concerns reported. Anecdotal reports of higher training losses under MMC suggest disparity between specialty training year 4 (ST4) and the first SpR year. the roles, controversies and losses of protected clinical special interest sessions and the research day are reviewed. UK psychiatric literature notes underutilisation and poor supervision of these highly valued protected training sessions, with suggestions for improvement. the sacrifice of protected training to service provision may have implications for training quality, leading to under-trained consultants in the long term, to the detriment of patients.
Psychiatrists' appreciation of statistical v. clinical significance: a quick test
Authors: Smith Alan , Warner James
Published: July 2009

Aims and Method

Pharmaceutical advertising material can confuse clinical and statistical significance. We used a brief questionnaire (five questions) to evaluate psychiatrists' appreciation of this difference. This approximated to the level of critical appraisal competence of the MRCPsych part 3 examination.

Results

Of the 113 questionnaires distributed 93 were returned complete (response rate 82%). Senior trainees were significantly better than junior trainees at correctly interpreting data (mean score (maximum 5) 2.61v.2.08; P = 0.04). Consultants did less well than senior trainees, although our sample of consultant respondents was too small for significance testing.

Clinical Implications

Learning critical appraisal for the MRCPsych examination may provide psychiatrists with valuable transferable skills and prevent gaps in our knowledge being exploited by misleading study data. Psychiatrists of all grades need to maintain their research appraisal skills and should not regard the MRCPsych examination as the end of their learning.
The need for brain imaging in clinical psychiatry
Authors: Davoren Mary , Doherty Anne , Breen Eugene , Sheehan John , Kelly Brendan D.
Published: July 2009

Aims and Method

To explore clinical indications for, and results of, brain imaging in general adult psychiatry. We reviewed the 100 most recent uses of brain imaging on in-patients at the Department of General Adult Psychiatry, Mater Misericordiae University Hospital, Dublin.

Results

Patients were of a mean age of 55.3 years. the most common indications for brain scans were cognitive impairment (33%) and other neurological concerns (e.g. seizures; 30%). Overall, 47% of scans were abnormal, with ischaemia (17%) and atrophy (10%) being the most common abnormalities. Patients with abnormal scans were older than those with normal scans (mean age 61.9 and 48.7 years respectively; P<0.001).

Clinical Implications

A high proportion of brain scans demonstrate abnormalities in general adult psychiatry patients, especially among older patients.
Sufism and Governmentality in the Late Ottoman Empire
Authors: Silverstein Brian
Published: July 2009

This article examines transformations in Sufi orders and in the status of Sufis in the late Ottoman Empire and argues that their increasing bureaucratization was an extension of increased rationalization of Ottoman administration and the normalization of the objects of governance into the Islamic sphere. The characteristically modern modes of power that Michel Foucault identified as governmentality and the particular kinds of knowledge and subjectivities associated with them were profoundly rearticulating the nature of Sufism in Ottoman lands by the last quarter of the nineteenth century. The article shows that changes in Sufi discourse and practice reflected the context of broader debates about Islamic traditions, institutions, and society at large in the late Ottoman Empire. This reevaluation of the experiences of Sufis in the later empire is important to an adequate interpretation of the relationship between Sufism and reform and of the concrete circumstances in which the orders were eventually proscribed by the republic in 1925.
The numerical comparison of flow patterns and propulsive performances for the hydromedusaeSarsia tubulosaandAequorea victoria
Authors: Sahin Mehmet , Mohseni Kamran , Colin Sean P.
Published: July 2009

The thrust-generating mechanism of a prolate hydromedusa Sarsia tubulosa and an oblate hydromedusa Aequorea victoria was investigated by solving the incompressible Navier–Stokes equations in the swirl-free cylindrical coordinates. The calculations clearly show the vortex dynamics related to the thrust-generating mechanism, which is very important for understanding the underlying propulsion mechanism. The calculations for the prolate jetting hydromedusa S. tubulosa indicate the formation of a single starting vortex ring for each pulse cycle with a relatively high vortex formation number. However, the calculations for the oblate jet-paddling hydromedusa A. victoria indicate shedding of the opposite-signed vortex rings very close to each other and the formation of large induced velocities along the line of interaction as the vortices move away from the hydromedusa in the wake. In addition to this jet propulsion mechanism, the hydromedusa's bell margin acts like a paddle and the highly flexible bell margin deforms in such a way that the low pressure leeward side of the bell margin has a projected area in the direction of motion. This thrust is particularly important during refilling of the subumbrella cavity where the stopping vortex causes significant pressure drag. The swimming performances based on our numerical simulations, such as swimming velocity,thrust, power requirement and efficiency, were computed and support the idea that jet propulsion is very effective for rapid body movement but is energetically costly and less efficient compared with the jet-paddling propulsion mechanism.
Redirection of center-of-mass velocity during the step-to-step transition of human walking
Authors: Adamczyk Peter G. , Kuo Arthur D.
Published: July 2009

Simple dynamic walking models based on the inverted pendulum predict that the human body's center of mass (COM) moves along an arc during each step,with substantial work performed to redirect the COM velocity in the step-to-step transition between arcs. But humans do not keep the stance leg perfectly straight and need not redirect their COM velocity precisely as predicted. We therefore tested a pendulum-based model against a wide range of human walking data. We examined COM velocity and work data from normal human subjects (N=10) walking at 24 combinations of speed (0.75 to 2.0 m s–1) and step length. These were compared against model predictions for the angular redirection of COM velocity and the work performed on the COM during redirection. We found that the COM is redirected through angular changes increasing approximately linearly with step length(R2=0.68), with COM work increasing with the squared product of walking speed and step length (R2=0.82), roughly in accordance with a simple dynamic walking model. This model cannot, however, predict the duration of COM redirection, which we quantified with two empirical measures,one based on angular COM redirection and the other on work. Both indicate that the step-to-step transition begins before and ends after double support and lasts about twice as long – approximately 20–27% of a stride. Although a rigid leg model can predict trends in COM velocity and work, the non-rigid human leg performs the step-to-step transition over a duration considerably exceeding that of double support.
The effects of age and behavioral development on honey bee (Apis mellifera) flight performance
Authors: Vance Jason T. , Williams Jason B. , Elekonich Michelle M. , Roberts Stephen P.
Published: July 2009

A critical but seldom-studied component of life history theory is how behavior and age affect whole-organism performance. To address this issue we compared the flight performance of honey bees (whose behavioral development and age can be assessed independently via simple manipulations of colony demographics) between distinct behavioral castes (in-hive nurse bees vs out-of-hive foragers) and across lifespan. Variable-density gases and high-speed video were used to determine the maximum hovering flight capacity and wing kinematics of age-matched nurse bees and foragers sampled from a single-cohort colony over a period of 34 days. The transition from hive work to foraging was accompanied by a 42% decrease in body mass and a proportional increase in flight capacity (defined as the minimum gas density allowing hovering flight). The lower flight capacity of hive bees was primarily due to the fact that in air they were functioning at a near-maximal wing angular velocity due to their high body masses. Foragers were lighter and when hovering in air required a much lower wing angular velocity, which they were able to increase by 32% during maximal flight performance. Flight performance of hive bees was independent of age, but in foragers the maximal wingbeat frequency and maximal average angular velocity were lowest in precocious (7–14 day old) foragers, highest in normal-aged (15–28 day old) foragers and intermediate in foragers older than 29 days. This pattern coincides with previously described age-dependent biochemical and metabolic properties of honey bee flight muscle.
Serotonin-induced high intracellular pH aids in alkali secretion in the anterior midgut of larval yellow fever mosquitoAedes aegyptiL.
Authors: Onken Horst , Parks Scott K. , Goss Greg G. , Moffett David F.
Published: July 2009

The anterior midgut of the larval yellow fever mosquito Aedes aegypti generates a luminal pH in excess of 10 in vivo and similar values are attained by isolated and perfused anterior midgut segments after stimulation with submicromolar serotonin. In the present study we investigated the mechanisms of strong luminal alkalinization using the intracellular fluorescent indicator BCECF-AM. Following stimulation with serotonin, we observed that intracellular pH (pHi) of the anterior midgut increased from a mean of 6.89 to a mean of 7.62, whereas pHiof the posterior midgut did not change in response to serotonin. Moreover, a further increase of pHi to 8.58 occurred when the pH of the luminal perfusate was raised to an in vivo-like value of 10.0. Luminal Zn2+ (10 μmol l–1), an inhibitor of conductive proton pathways, did not inhibit the increase in pHi, the transepithelial voltage, or the capacity of the isolated tissue to alkalinize the lumen. Finally, the transapical voltage did not significantly respond to luminal pH changes induced either by perfusion with pH 10 or by stopping the luminal perfusion with unbuffered solution which results in spontaneous luminal alkalinization. Together, these results seem to rule out the involvement of conductive pathways for proton absorption across the apical membrane and suggest that a serotonin-induced alkaline pHi plays an important role in the generation of an alkaline lumen.
Masticatory (`superfast') myosin heavy chain and embryonic/atrial myosin light chain 1 in rodent jaw-closing muscles
Authors: Reiser Peter J. , Bicer Sabahattin , Chen Qun , Zhu Ling , Quan Ning
Published: July 2009

Masticatory myosin is widely expressed among several vertebrate classes. Generally, the expression of masticatory myosin has been associated with high bite force for a carnivorous feeding style (including capturing/restraining live prey), breaking down tough plant material and defensive biting in different species. Masticatory myosin expression in the largest mammalian order, Rodentia, has not been reported. Several members of Rodentia consume large numbers of tree nuts that are encased in very hard shells, presumably requiring large forces to access the nutmeat. We, therefore, tested whether some rodent species express masticatory myosin in jaw-closing muscles. Myosin isoform expression in six Sciuridae species was examined, using protein gel electrophoresis, immunoblotting, mass spectrometry and RNA analysis. The results indicate that masticatory myosin is expressed in some Sciuridae species but not in other closely related species with similar diets but having different nut-opening strategies. We also discovered that the myosin light chain 1 isoform associated with masticatory myosin heavy chain, in the same four Sciuridae species, is the embryonic/atrial isoform. We conclude that rodent speciation did not completely eliminate masticatory myosin and that its persistent expression in some rodent species might be related to not only diet but also to feeding style.
Computational Experience with a Software Framework for Parallel Integer Programming
Authors: Xu Y. , Ralphs T. K. , Ladányi L. , Saltzman M. J.
Published: July 2009

In this paper, we discuss the challenges that arise in parallelizing algorithms for solving generic mixed integer linear programs and introduce a software framework that aims to address these challenges. Although the framework makes few algorithmic assumptions, it was designed specifically with support for implementation of relaxation-based branch-and-bound algorithms in mind. Achieving efficiency for such algorithms is particularly challenging and involves a careful analysis of the trade-offs inherent in the mechanisms for sharing the large amounts of information that can be generated. We present computational results that illustrate the degree to which various sources of parallel overhead affect scalability and discuss why properties of the problem class itself can have a substantial effect on the efficiency of a particular methodology.
Impact Resistance and Tensile Properties of Metals at Subatmospheric Temperatures
Authors: Gillett H. W.
Published: July 2009

The advances that have been made in the field of low-temperature engineering demand a more thorough knowledge of the low-temperature properties of metals. Project No. 13 on Effect of Subatmospheric Temperatures on the Properties of Metals, of the Joint Research Committee on Effect of Temperature on the Properties of Metals, is charged with the recording of progress of such knowledge. This subcommittee arranged the round-table discussion held at the annual meeting of the A.S.T.M. in June, 1939. The résumé prepared by Foley (1) of this discussion summarizes in general terms information that has become available since the summary by Russell (2) in 1931. It was the impression of the Joint Committee that still more low-temperature data might be procurable from laboratories concerned with the production of metals for low-temperature service or their application to such conditions. Accordingly Subcommittee 13 was instructed to circularize such laboratories, and to correlate and report upon the unpublished information that might thus come in, as well as upon other pertinent information in the literature not already adequately summarized in the two symposia. This report has been prepared for the subcommittee at Battelle Memorial Institute by H. W. Gillett, with the cooperation of H. W. Russell, S. L. Hoyt, and H. C. Cross.. This group has made the interpretations of the published and unpublished data cited.
Introduction
Authors: Adams Robert C.
Published: July 2009

The inadequacies of composition specifications for lubricating greases have become increasingly apparent in recent years. The multiplication of soap bases and their mixtures, the introduction of fluids other than mineral oil, and improvements and variations in manufacturing processes have made it virtually impossible to estimate the suitability of a grease for a given purpose by laboratory determination of the proportions of its ingredients and its traditional physical properties. Some kind of service test or performance test is required for reliable evaluation and selection of lubricating grease. Many makers and users of grease have recognized the need for suitable test methods and have made separate efforts to develop them. The resulting divergencies in apparatus and procedure have yielded considerable information, but little progress toward general acceptance of any method or group of methods. No one now predicts the adoption of one testing device which can sort and appraise all greases for their multifarious lubricating uses, but it should be possible to reach agreement on suitable performance tests for limited categories of lubricants. Technical Committee G of Committee D-2 chose for its first standardization effort of this sort the development of acceptable functional tests for greases to be used in anti-friction bearings in such industrial applications as electric motors. This narrow limitation of the field of prospective agreement seemed necessary for reasonably prompt completion of the project. The project was assigned to a sub-section of the committee about three years ago.
Grease—An Oil Storehouse for Bearings
Authors: Wilcock Donald F. , Anderson Marshall
Published: July 2009

The widespread use of antifriction bearings in electric motors is accompanied by an increasing interest in grease lubrication. Lubrication of antifriction bearings by greases offers the advantages of cleanliness and long life. With this expanding interest in grease lubrication has come an awakening interest in the sound engineering of bearing installations employing grease as the lubricant. In order to understand how to engineer a bearing installation we have to know something about the mechanism by which the lubrication takes place and something about the properties of the lubricants commercially available, so that the proper choice of both design and grease might be made. The engineer is, therefore, faced not only with the problem of discovering the mechanism of grease lubrication but also with the problem of determining the behavior of actual equipment. Usually the study of life expectancy in actual equipment is a very lengthy one, and he resorts to some form of laboratory testing on an accelerated scale in order to obtain the desired information more quickly. He is then faced with the additional problem of correlating his accelerated tests with the results he observes in actual equipment. This sort of study is a time-consuming one and a problem which requires many years to solve. This paper is an effort to illustrate the manner in which the problem has been attacked in our company. It will also indicate some of the theories concerning the mechanism of grease lubrication which have resulted from our experience, and the effect of these theories on the design of bearing installations. We will also attempt to show how the laboratory results can be correlated with field experience.
Laboratory Performance Tests for Antifriction Bearing Greases
Authors: Herbst M. , Prendergast W. A. , Barnett R. S. , Finn W. J. , Puryear O. P.
Published: July 2009

The need for a suitable laboratory test that will evaluate greases for ball and roller bearing service and allow correlation of test results with field service is widely recognized. Many machines have been developed for this purpose but correlation among machines and between laboratory tests and field service has in many cases not been too satisfactory. Extensive field tests are the only method by which satisfactory and final proof of performance may be obtained. The matter is complicated by the wide variety of service conditions under which ball and roller bearings operate. The Texas Company, recognizing the shortcoming of depending upon any one laboratory test, has developed at Beacon Laboratories, a number of machines for evaluating ball and roller bearing greases. Some are used as screening tests, others for long-time tests. Machines developed by others also have been investigated on a cooperative basis. In this paper, emphasis is placed on room and elevated temperature conditions, rather than the specialized subject of low temperature evaluation. The following machines, representative of those now in use by The Texas Company, will be described, along with typical test results on various types of greases: 1. Grease-Breakdown Machine. 2. Torque-Breakdown Machine No. 1. 3. Torque-Breakdown Machine No. 2. 4. Beacon High-Temperature, High-speed Ball Bearing Performance Test. 5. SKF Machine—original and modified for elevated temperatures. 6. Beacon Wheel Bearing Grease Tester. 7. Beacon Vibrating Wheel Bearing Grease Tester.
Factors Affecting Simulated Service Tests of Greases
Authors: Collegeman Sidney M. , Belt John R.
Published: July 2009

There have been many attempts to establish a reliable means for predicting the service life of a grease. Greases have been selected on the basis of composition, physical characteristics, and operation in actual equipment. More recently, simulated-service tests have been used and have been accepted as a dependable means of evaluating greases. These tests are in most cases less time consuming than those in actual standard equipment. However, there is still a need for a means of accelerating testing to obtain results in a shorter time without reducing their reliability. This paper deals with our attempts to accomplish this objective. The initial work on the evaluation of greases by performance tests led to the development of the Navy Grease Machine. This work was described by Adams and Patten in 1941. This machine was abandoned when reports from the field indicated that the premises on which its evaluation of greases was based were invalid. It then was necessary to devise a test which would more nearly simulate service conditions. Simulated-service testing of greases under conditions of high temperature and high speed was started with an apparatus designed to rotate a No. 204, grease-lubricated ball-bearing at 10,000 rpm. while maintaining any desired temperature. A Specification for High Temperature Water Resistant Grease was subsequently written around this apparatus using as the criterion of acceptability a minimum of 300 hr. satisfactory bearing operation at a temperature of 300 F. This work was summarized last year by Adams and Collegeman. The information and experience gained with this apparatus were used to design and construct an improved tester which permits better control of more variables. This apparatus has been given the name of Universal Grease Tester, a single unit of which is illustrated in Fig. 1. This apparatus recognizes and provides control of four variables: temperature, speed, bearing size, and bearing load, both radial and axial. Permissible temperatures with this installation range up to 500 F., speeds up to 20,000 rpm., bearing sizes up to 60-mm. bore, and bearing loads up to 50 lb. The radial-load range can be extended readily by modification of accessories without changing the basic design of the unit. In order to obtain in a reasonable time sufficient replicate runs for appraisal of both the magnitude and the variability of the results, thirty units of this tester have been installed. Two views of the assembly are shown in Figs. 2 and 3.
Low Temperature Behavior of Organic Plastics
Authors: Nason H. K. , Carswell T. S. , Adams C. H.
Published: July 2009

When exposed to low temperatures, organic plastics undergo changes which may be classified broadly as reversible and irreversible. Reversible effects usually include dimensional changes due to thermal contraction and loss of moisture, increased modulus of elasticity, increased yield and ultimate strengths, decreased ductility, and—most frequently, though not in every case—decreased resistance to impact. Irreversible effects may include dimensional changes due to change of state, physical failure due to lack of sufficient ductility to respond to dimensional changes, crystallization, and freezing of plasticizers or absorbed water. In either classification, extent and rapidity of every effect varies greatly, depending upon specific environmental conditions and the particular material involved. Data are presented to illustrate these various effects. Significance from a practical point of view is shown by typical examples. Also, the importance of correct design of parts is emphasized. The paucity of data at low temperatures for such properties as fatigue strength, stress endurance, and electrical constants is pointed out.
Effects of Subatmospheric Temperatures on the Properties of Non-Ferrous Metals
Authors: Mochel Norman L.
Published: July 2009

The subject assigned to me for consideration at this Symposium may be covered, I believe, in a very simple and rather brief statement. I do not believe that it requires any lengthy presentation of data, for the reason that such data have been well prepared already for all who may be interested. The Joint Research Committee on the Effect of Temperature on the Properties of Metals has summarized data on the effect of low or subatmospheric temperatures on the properties of metals on several occasions. In the 1931 Symposium at Chicago, there was included an excellent review on this subject by H. W. Russell of Battelle Memorial Institute, and here one may find a great deal of information on the effect of low temperatures on the nonferrous metals and alloys.
Introduction
Authors: Batchelder A. H.
Published: July 2009

The lubricating oils considered in this symposium are of an entirely new type and differ from the previous heavy-duty oils in that they contain from five to ten times as much additive. This is exemplified by the ash values of some of these oils which are above 2 per cent. The high-additive oils were developed primarily at the request of the Caterpillar Tractor Co. to meet a field condition involving severe operation of engines using high sulfur fuels. These oils are identified as “Series 2” oils and the Caterpillar experience with them is reported to be excellent. The excellent success with the Series 2 oils in Caterpillar engines has led investigators to determine if other problems in other engines could also be corrected by the use of these oils. This is the first time that actual adequate field service data on Series 2 oils have been presented publicly, and the papers and formal discussions will give a well-rounded presentation from the stand-points of both the equipment and lubricants manufacturers. In view of the relatively greater extent to which “dieselization” has taken place in the West as compared to other regions, and of the special problems encountered here, it is especially appropriate that this first symposium be held on the West Coast. In spite of the short time since introduction of these oils, a considerable background of results has been obtained, and these data are the basis for this symposium. It is unlikely that the results from the various laboratories will be in complete agreement, which should stimulate discussion and further experimentation progress. The exchanges of information in symposiums of this type have contributed to the solution of such problems in the past, and continued cooperative effort should be equally valuable in the future.
Does Service Performance Justify Higher Quality Lubricating Oils?
Authors: Bassett W. B.
Published: July 2009

In order to provide a partial answer to the question propounded in the title, it will be necessary to present a review of service experience and a limited amount of laboratory engine test data. The real value of any lubricating oil can be determined only by actual service experience; but laboratory data are usually much more reliable for obtaining comparative information on ring sticking and deposit-forming tendencies as well as engine wear. Many authors have contributed toward a better understanding of the lubrication requirements which resulted in the development of heavy-duty oils defined by U. S. Army Specification 2-104B, and it should be unnecessary to cover this earlier work. Similarily, other authors have covered the effects of fuels, operating conditions, and design which adversely affected engine deposits and wear. In November, 1947, Blanc (1) concluded that heavy-duty oils of the 2-104B type, while better than straight mineral oils, were not satisfactory with respect to wear, ring sticking, and piston deposits when using diesel fuels of high sulfur content. He also commended on the apparent spread in performance level of different 2-104B products. Figure 1 shows comparative results of Caterpillar, single-cylinder engine, 480-hr. L-1 tests on a 2-104B lubricant using diesel fuels of approximately 0.15 per cent and 1 per cent sulfur content. The deleterious effects of sulfur as originally outlined by Blanc are today well recognized (2).
High Detergency Motor Oils
Authors: Boehm A. B. , Tongberg C. O.
Published: July 2009

This paper presents results obtained with detergent-type motor oils in laboratory and field studies under low temperature conditions. Light truck and passenger car field tests, carried out under rigidly controlled conditions, show that a significant reduction in sludge and ring zone deposits can be obtained by the use of low or moderate concentrations of detergent type additives. However, in light truck field tests, a high detergency motor oil showed no advantage over a high quality, heavy duty oil of lower additive content and detergency level. It should not be assumed, therefore, that high additive concentrations or high levels of detergency per se, are a guarantee of outstanding performance under all service conditions. A system of running low temperature, CRC, FL-2 laboratory engine tests on experimental oils based on the use of a standard lubricating oil and fuel combination is also presented. Ring zone and sludge deposits obtained in this test correlate with those obtained under low temperature engine service conditions in the field. However, the absolute levels of deposits in the FL-2 test are low, and there is a need for a better laboratory engine test technique for measuring the low temperature engine service performance characteristics of motor oils.
Five Years' Experience with Special Heavy-Duty Oils
Authors: Edgar J. A. , Jeffrey R. E.
Published: July 2009

More than five years' experience in the field, including two years of commercial application, have demonstrated the ability of a new class of lubricants to handle engine applications where even the best of the heavy-duty type oils were unsuccessful. The Special Heavy-duty oils, also referred to as “Caterpillar, Series 2 Oils” and “Ordnance, Supplemental List 2 Oils,” have been particularly outstanding in diesel engines where difficult fuel and operating conditions prevail. Practically all corrosive wear and engine fouling in such diesels has been eliminated. Unsatisfactory experience with these oils in such applications is almost unknown. The new lubricants offer the possibility of economical use in many diesel engines over and above the economics to be realized through reduced maintenance. Where oil-change period can be adjusted to fuel and operating conditions, the long-lived Special heavy-duty oils normally will be more economical than any of the ordinary heavy-duty type oils. There are definite indications in natural gas engines that the Special heavy-duty oil is of benefit in extending engine life. These engines are often limited by piston lacquer, and in those cases reduction of lacquer leads to more satisfactory operation and longer life. Work in the gasoline engine field to date has indicated that the Special heavy-duty oil performs at least as well as other types of lubricant. Definite advantage can be obtained as to engine cleanliness with the new oil. Excessive combustion chamber deposits leading to rapid increase in octane requirement and short spark plug life have not developed. Exhaust valve deposits have been observed, but there is no clear record that they adversely affect valve life. Our conclusions at this time are that, while gasoline engines do not require an oil of this type, some advantage may accrue to its use in certain types of service, and there seem to be no limiting factors.
Lubrication Problems and Requirements of Gas Turbine Equipment
Authors: Linn Frank C.
Published: July 2009

The gas turbine, similar to other prime movers, has had a long history. It is only within recent years, however, that the application of the gas turbine as a prime mover has been put on a practical basis. Even now there are only a few gas turbine units being used for the generation of electric power. In order to use the gas turbine economically it has been necessary to use it in high-temperature ranges. The development therefore of the gas turbine has been limited by the development of materials that can be used at high temperatures. Gas turbines are being designed to operate at initial temperatures as high as 1500 F.
Operating Experience and Problems Relative to Lubricating Systems of Steam Turbine Sets for Utilities
Authors: Estcourt V. F.
Published: July 2009

Steam turbine lubrication has passed through three phases. The first was typified by oils not sufficiently refined for good stability and operating in bearings with insufficient cooling and excessive moisture infiltration from shaft seals. The second phase was initiated by an effort to produce a much more highly refined oil, and this had some unfortunate results in operation due to early breakdown of new oils in the presence of rust from the oil piping, which in turn was the indirect result of over-refining. In the third phase this was remedied by the introduction of inhibitors; turbine lubrication today has very long service life expectancy. However, the ultimate life of a high-grade inhibited oil is not definitely known because insufficient time has elapsed since the advent of inhibitors, and the ultimate breakdown of some inhibited turbine oils may occur rather suddenly. Reliable laboratory tests are badly needed for predicting the probable service life of a new oil and for evaluating old oils in operating service, so that their condition can be accurately determined before a breakdown actually occurs. Some standard tests for turbine oils are discussed in terms of their value to the operator, and their limitations are pointed out by actual case histories. Some modifications of existing standard stability tests are proposed and these are supported by laboratory test data. The need for further research along specific lines is suggested, and also discussed is the problem of establishing safe limits for the quality of an oil in service before it must be replaced.
Lubrication of Marine Turbine Propulsion Equipment
Authors: Jones Frederick S.
Published: July 2009

The successful operation of marine turbine propulsion equipment depends in no small way on the care used in the design, manufacture, operation and maintenance of the lubrication system. Each has a part in providing for the elimination of contamination that may be detrimental to reliable operation. The most common contaminant is water, the presence of which causes the appearance of rust and other metallic compounds. The chief sources of water are shaft seal leakage, condensation, and oil cooler leakage. The advent of rust-inhibited turbine oils has been of material assistance in suppressing the formation of rust, particularly the magnetic iron oxide type, when a limited amount of water, classified as entrained moisture, is present. The A.S.T.M. rust test has been most valuable in predetermining the ability of turbine oil to offer protection against rusting when entrained moisture is present. But, depending upon quantity and chemical content of the water in the lubrication system, rust-inhibited oils may not offer satisfactory protection. It then becomes necessary to determine the reasons for the water being present and eliminate them. Thus we turn to the mechanical aspects of the propulsion equipment for the final solution of the problem. When the design, manufacturing, installation, and operating factors, about to be discussed, are given due consideration by the representatives of the ship owners, shipyards, machinery manufacturers, and oil suppliers, water and associated evils should be absent from the consideration. Only then may the best service be expected from the equipment.
The Use of Creep Data in Design
Authors: Cross Howard C. , Jackson L. R.
Published: July 2009

The development of high-speed aircraft has introduced some new design problems. One of the most difficult problems is the designing of structures to operate under high stresses at relatively high temperatures. For applications in which stresses and temperatures are reasonably uniform over long periods of time, tension creep data have been used for design purposes. For many aircraft applications, it is usually more important to design against collapse by buckling than against failure by tension loading. In this case, compression creep data are needed. Very little is known concerning the relation between tension creep and creep in compression, torsion, and under combined stresses. This paper describes the creep data available at the present time and discusses the limitations in interpolation and extrapolation of the data. It is indicated what types of additional data would be of greatest usefulness in the design problems confronting designers in the use of metals for high-temperature service.
Gear Lubricants Used in Steel Plants
Authors: Pelly John F.
Published: July 2009

The purpose of this paper is to give a general idea of the gear lubricants used in a steel plant. A list of lubricants and viscosities used in three different plants will be shown. As they have all been used for many years, with a few exceptions, it can be assumed that they are all satisfactory. It is our belief, however, that a wider tolerance in viscosities would give equal satisfaction. This is borne out by a study of the data presented below showing gear lubricants used in these plants.
Gear Set Servicing by the Cathode Ray Oscilloscope
Authors: Purdy A. R. , Goffe J. H.
Published: July 2009

The conditions that lead to gear tooth failures are very often difficult to determine. Therefore, any tool that aids in identifying the causes of failure is of interest to those who service gears. A cathode ray oscilloscope can be used for this purpose. As we all know, the instrument shows on its screen a series of curved harmonic Unes, thereby transposing vibration into visual form. By photographing the oscilloscope screen, permanent records of these curves are secured. The application of the oscilloscope in tracking down field difficulties is the outgrowth of the use of this instrument in gear lubricant test work in the Socony-Vacuum laboratories. Before describing the laboratory test work, a detailed case history will be given where the oscilloscope was used successfully in solving a field problem.
Lubrication of Naval Gearing
Authors: Simpson R. T.
Published: July 2009

The Navy's interest in reduction gear design and performance is, I believe, unquestionably unique. And so, likewise, is its position with regard to the control of those factors which determine gear design and performance. It is the world's largest user of high-powered, high-speed reduction gears, but it is not a gear designer, nor is it a gear producer. However, its stake in the business is of such enormous magnitude that through the years it has utilized every device at its command to promote the development of improvements in design which would result in better performance of the gears in its ships. In October, 1944 these efforts were focused and given tangible form when, at the direction of Admiral Mills, the marine gear building industry was invited to participate with the Bureau in a cooperative effort to solve several serious problems of wartime reduction gear maintenance which appeared to be almost epidemic in proportions. Admiral Mills felt that a significant contribution could be made to the war effort, if, through the pooling of the scientific and technical talent of the gear builders represented, quicker or more reliable solutions to these problems could be obtained. Thus, the Navy Gear Industry Committee was formed. The degree of cooperation we received from that group was so excellent, and the results achieved thereby were so beneficial that, as the war gradually progressed from V-E Day to V-J Day, this group continued to function as an advisory body to assist the Bureau in the guidance, analysis and evaluation of its gear development program. This program, which during the past four years has been the most extensive and far reaching ever undertaken by the Navy, has had as its goal the development of equipment which is substantially lighter in weight, smaller in size, more reliable in operation, and easier to maintain.
Developments in Gear Design and Their Lubrication Requirements
Authors: Collins L. J.
Published: July 2009

There are a number of questions which arise in discussions on gear lubricants and a few are listed below: 1. What is the purpose of a lubricant? 2. What would be the characteristics of a gear that would operate without lubrication? 3. Is it possible to produce such a gear? 4. How important is surface finish? 5. Is the same degree of surface finish desired or necessary in all instances? 6. Is it necessary to use lubricants of high viscosity? 7. Does the sliding velocity determine the viscosity of the lubricant, or the surface finish desired? All machined surfaces are made up of hills and dales. The finer the surface finish the smaller are the hills and dales. If two such machine surfaces are in contact and if it is desired to move one with respect to the other, interference between the hills on the two surfaces make it necessary to apply a force to produce motion. If the hills and dales on the two mating surfaces are so arranged that every hill on one falls into a dale on the other, and if the faces of the hills are perpendicular to the direction of the desired motion, it will be impossible to produce motion unless a force is applied of sufficient magnitude to shear off the hills. The shearing off of the hills results in heat being generated.
Physical Concepts of the Establishment of the Lubricating Oil Wedge and its Associated Load Carrying Capacity for the Mating Tooth Surfaces of High-Speed Gears
Authors: Gatcombe Ernest K.
Published: July 2009

This paper presents some of the physical concepts perceived in the establishment of the lubricating oil wedge which separates the mating tooth surfaces of high-speed gears. (See Fig. 1 for an indication of the location of the oil wedge.) Emphasis is placed on the presentation of the physical concepts involved rather than on the mathematics of the subject matter. The work presented may be divided into the following four parts: 1. The establishment of the oil wedge and its associated load-carrying capacity for oil wedges of various shapes, with and without normal and tangential surface motions. 2. Factors which influence the load-carrying capacity of the oil wedge between gear tooth sufaces. 3. Suggested features of the lubricants and gear materials which may be improved upon to give higher tooth load-carrying capacities. 4. Summary.
Introduction
Authors: Ball Leslie W.
Published: July 2009

In 1936, prior to the second world war, and again in 1942 during the war, the American Society for Testing Materials conducted symposia on industrial radiography. These symposia were published by the Society in book form. Both the holding of the symposia and publishing information about the techniques and fields of application did much to build up industrial radiography practice as an important factor in the mobilization of American industry for national defense. After the war there was a widespread expectation that industrial radiography and other associated methods of nondestructive testing would lapse into a minor, routine rôle in our industrial production. Actually the postwar years have brought a great decrease in routine finished-product inspection, but at the same time there has been a fascinating surge forward in two other aspects of this still young and vital technology. These rapidly developing aspects are in the engineering of radically new equipment and in the skilled exploitation of non-destructive testing in the management of engineering and material-processing development projects. In both cases the progress that has been made led the Society to undertake sponsorship of symposia that would be followed by publication. Two symposia were held at the Annual Meeting in 1949, one on Radiography and one on Ultrasonic Testing, and a further symposium on the management and economic aspects of non-destructive testing is scheduled for the Annual Meeting in 1950. In the present volume, covering the 1949 symposium, three papers deal with progress in the development and application of electrostatic and betatron-type X-ray generators operating at potentials above the familiar one million volt range. These machines make available to industry not only penetration of steel up to 16 in. in thickness but also the ability to observe the internal structure of engineering parts and assemblies with a sharpness and precision resulting from a very small X-ray source and great freedom from fogging by X-ray scatter.
Recent Progress in Flash Radiography
Authors: Clark J. C.
Published: July 2009

The use of the Westinghouse Micronex X-ray equipment for research problems involving material motions from 2500 to 25,000 ft.per sec. is discussed and illustrated by selected flash radiographs. The radiographs of the faster motions show clearly that the duration of the X-ray pulse produced by the Micronex apparatus is of the order of two microseconds. A circuit is described which, when used with a Micronex X-ray tube, will produce single X-ray pulses lasting no longer than 1/10 microsecond.
Mobilizing the Van De Graaff Generator for Precision Radiography
Authors: Burrill E. Alfred
Published: July 2009

A two-million-volt X-ray generator has been developed which is not very much larger than a household refrigerator and which is so light that maneuvering it presents no problem in installations requiring the inspection of heavy objects. The penetrating power, sensitivity, and latitude of two-million-volt X-radiation can now be utilized more advantageously by virtue of a flexible mount. In addition, the definition obtainable from a focal spot smaller than the head of a pin permits more definitive radiography of complex objects. The need for such an instrument for the non-destructive testing of bulky, immovable objects has been voiced repeatedly. The Van de Graaff generator, introduced to the Navy by Massachusetts Institute of Technology a few years ago, has been developed to answer this need. New techniques in high-voltage X-ray tube construction, improvements in electrical designs, simplified controls, and auxiliary equipment have all contributed to the ultimate compactness of this type of X-ray source. With its size and weight reduced to reasonable figures for mobility, the two-million-volt generator can be easily adapted to existing load-handling techniques. Several Van de Graaff generators have already been built for use in cancer therapy, installed in a mounting arrangement which allows vertical movement and tilting in one plane from horizontal to vertical. This paper describes the generator and its flexible mount, both readily adaptable to industrial radiography. In addition, the design of a mobile unit for shipyards, foundries, and other similar establishments is discussed.
A Universal Exposure Calculator for Radium Radiography and its Application to Current Radiographic Films and Techniques
Authors: Kahn Noah A. , Imbembo Emil A. , Bland Jay
Published: July 2009

This paper describes an exposure calculator for radium radiography so designed and constructed as to permit its use as a standardized exposure calculator in connection with steel and other materials and with all types of industrial radiographic film, or with radiographic techniques which aim at image density levels higher or lower than the normal net density of 1.00. Its use requires a knowledge of the speed rating factors for the particular film and technique employed. The paper also describes the method of determining the film speed rating factors for use with the universal exposure calculator and presents data on the speed rating factors of a number of commercial types of radiographic film.