Document D0VqajkY5byn55yDNLx49pKo

ECHANICAL ENGINEERING Published by The American Society of NLechanical Engineers 6olumb o 9Number Contents for September, 1938 the cover......................................................................................Providence, R. I., at Night H. N.ENGINEERING AND HEALTH.............................................................. Davis 663 A NEW METHOD IN TOOLING AUTOMATIC SCREW MACHINES . . . E........................................................................... . . . . W. Brinkman 666 HEAT TRANSFER TO BOILING LIQUIDS....................................................................................... . . E. T. Sauer, H. B. H. Cooper, G. A. Akin, W. H. McAdams 669 PERSONALITY: THE MAIN FACTOR IN PUBLIC SPEAKING . S. M. Tucker 675 ENGINEERING FACTORS INVOLVED IN ORCHARD HEATING . F. A. Brooks HISTORY OF RUBBER AS AN ENGINEERING MATERIAL. . W. C. Geer BRITAIN WRESTLES WITH UNEMPLOYMENT . . . D. V. BrotVU 677 682 685 CONTRIBUTIONS OF METALLURGY TO ENGINEERING PROGRESS ('Concluded) W........................................................................................................................................................................................................................................ R. Barclay 687 DYNAMIC RELATIONS BETWEEN MOVING LOADS AND STRUCTURES . . K............................................................................................................................ R. Bernhard 696 III .engineering's PART IN THE DEVELOPMENT OF CIVILIZATION-- ....................................................................................................................................... D.C. Jackson 703 EDITORIAL..............................................................661 A.S.M.E. BOILER CODE .... 709 REVIEWS OF BOOKS A.S.M.E. NEWS INDEX TO ADVERTISERS. 36 710 715 PLAINTIFF'S EXHIBIT ASM-38 OFFICERS OF THE SOCIETY: Harvey N. Davis, President W. D. Ennis, Treasurer C. E. Davies, Secretary PUBLICATION STAFF: George A. Stetson, Editor Frederick Lask, Advertising COMMITTEE ON PUBLICATIONS: M. H. Roberts, Chairman G. F. Bateman C. B. Peck Coleman Sellers, 3d F. L. Bradley ADVISORY MEMBERS OF THE COMMITTEE ON PUBLICATIONS: \Y. L. Dcdley, Seattle, Wash. A. N. Goddard, Detroit, Mich. E. J. Kates, New York, N. Y. L. S. Marks, Cambridge, Mass. J. M. Todd, New Orleans, La. Jiinior Members, A. E. Blirer, Edgewater, N. J., and R. F. Warner, Jr., New York, N. Y. Pablishcd nwnchiy tv The American 5o;ieiy of Mechanical Engineer*. Publication Oif.cc at 20ch and Northampton Streets, Easton, Pa. Editorial and Advertising departments at the head quarters of the Society, 29 \\>>r Thir:v*Ninth Street, New York, N. Y. Cable address, "Dynamic/* New York. Price 60 cents a copy, $5X0 a year; to members and affiliates, SO cent# a copy, $4 CO a year. Postage tn Canada, 75 cents additional, to foreign countries, $1.50 additional. Changes of address must be received at Society headquarters two weeks before they arc to be effective on the mailing list. Please .send old as well as new address.... By-Law: The Society shall not be responsible for statements or opinions advanced in papers or .. . printed m :r> publications 'Bl3. Par. 4%,. .. . Entered as second-class matter at the Pose OrHrc at Easton, Pa., under the Act of March 3.1879. . . Acceptance for mailing at special rate of postage provided for insertion I10J, Act of October 3, 1917, authorised on January 17,1921.... Copyrighted, 2938. by The American Society of Mechanical Engineers. Member of the Audit Bureau of Circulations. * 384 Mechanical Enginebrin New Optical Glass transparent film. Dr, Hauser also indicated that Alsifilm w" take ordinary printing, colored inks, and printing pastes, or ` SCIENCE NEWS LETTER. may be colored throughout, filled and coated, oiled, or given* surface pattern. Unaffected by climate, mold, or insects, ici THE DISCOVERY of a, way to make optical glass out of seen as a permanent record material, handled as easily as an rare chemical elements instead of common silica permits paper. the production of a glass which has a very high index of re Alsifilm is co be introduced commercially by the Re fraction and a low dispersion, it is disclosed in a patent just Corporation for the Massachusetts Institute of Technology i granted to Dr. George W. Morey, of the geophysical laboratory Dr. Hauser. At the present stage of development none of i of the Carnegie Institution of Washington, D. C. According material is available for distribution, but a small commcr--' to a description of the new glass in Science Newt Letter, for March unit is being constructed and samples will be available within 25, 1939, the discovery may be a major stride in the advance of few months. The cost of Alsifilm cannot well be csrimat1 photography, permitting lens makers to produce "faster" and until further progress toward the production of larger quantitf better lenses. has been made. Some of the optical glasses of Dr. Morey have the highest index of refraction (light-bending power) ever reported; more than 2. Only comparable refraction is that of the diamond, Mineral Wool which is about 2.41. Moreover, high index of refraction and low dispersion permit better corrections for chromatic aberra MINING AND METALLURGY tion, the annoying property of some lenses of bringing different colors to different focuses. Chemical elements most people have never heard of are used in producing the glass. Yttrium, lanthanum, columbium, hafnium, tantalum, zirconium, strontium, boron, and barium arc some of the rare elements, The' new work is a continuation of efforts made in the United States since the World War to produce better optical glass. MINERAL WOOL is a substance composed of fine, inter laced mineral fibers having the appearance of loose woo or cotton. It is a fibrous, glasslikc material composed print1 pally of silicates of calcium and aluminum, with other min'' constituents. The production of it has grown to such an ejc. tent that last year the output was valued at $30,000,000, aj compared to an output in 1933 valued at $1,700,000. T`v industry is still growing vigorously and should profit from the Alsifilm--A New Material expected activity in building in 1939, for two thirds q` the material is used for building insulation and to assist in fit retarding, in both new and old houses. It is also a concomica INDUSTRIAL BULLETIN OF ARTHUR D. LITTLE, INC. of air conditioning. A description of the production, fabrica tion, and application of mineral wool is contained in an article' ANEW TYPE of transparent film material, for which the name "Alsifilm" has been suggested, has been reported written by J. R. Thocncn, supervising engineer, U. S. Bureau o Mines, and published in the February, 1939, issue of Mining by Dr. Ernst A. Hauser, according to the Industrial Bulletin aonfd Metallurgy, the journal of the A.I.M.E. Jf Arthur D. Little, Inc. Alsifilm, it is said, can be made from Mineral wool is a generic term, says Mr. Thocncn, covering. clay and may find uses as a mica substitute, an indestructible a number of similar products differentiated chiefly by the raw paper, a fireproof wrapping material, and a waterproof coating materials from which they are made, such as rock wool, slag; for paper articles. wool, and glass wool or glass silk. Rock wool, as its name: The clay used is an especially "pure" cypc of bentonite, made implies, utilizes as raw materials limestone, dolomite, shale| up of alumina, silica, and-watcr, and the individual particles arc and clay, combined with silica in the form of sandstone, of so small that most of them fall within the colloidal range. It quartz, or as an ingredient of the other rocks. Slag wool is has been found that the finer part of the colloidal fraction of the made from slags resulting from the reduction of iron, lead, of clay when mixed with the appropriate amounts of water forms copper ores. Other materials, such as limestone or silica, nmj? a gel. If this gel is evaporated, the particles draw toward one have to be added depending on the chemical analysis of i another in such positions that they become permanently fixed original slag. Glass wool is made from the same materials by their attraction for each ocher, in strings or tiny fibrils. that are required for making glass. Basically, these are sodt: These strings in turn mat together similarly to the matting of ash, limestone, and silica. The addition or partial wood fibers in forming paper, or wool in felt, so that ultimately sticution of other ingredients changes the characteristics of t die resulting structure is that of a tough, coherent, independent glass; similar substitutions in the raw mix enable the manu film. facturer to alter the character of the wool blown. Alsifilm may be made thick so that it is stiff and brittle, and In the manufacture of mineral wool, a stream of molten rocky in this state is proposed as a substitute for mica, for it looks like slag, or glass is directed to a jet of cither steam or air which mica, has similar electrical properties, and is chemically inert. blows it into wool. Technically, however, the process is no" Both mica and Alsifilm arc composed of alumina, silica, and so simple, since many factors enter into the process, all of whic^ bound water, possibly in much the same proportions and dis muse be under rigid control co assure a commercial prodn tribution. Merely projecting a molten stream of rock into a jet of start In presenting his findings to the Technical Association of the does not always produce wool. Chemical constituents of ch Pulp and Paper Industry, Dr. Hauser stated that the new film raw material, degree of viscosity, and temperature of the slag- may be made completely inert to oils, greases, organic solvents, size of slag stream, length of fall, and che pressure of the st< and strong acids and salts. There arc obvious useful applica or air are only a few of the many variables that must not onl tions for such a material available as a film or a thread, and be controlled individually but coordinated to make the process possessing these properties. In the thin, flexible form, for successful in producing the kind of wool desired. cable wrapping, it would offer long life and the needed electrical The usual process consists of mixing raw materials withco* properties. Foods, especially those which tend to take up in alternate layers in a watcr-jnckcced steel cupola, igniting th odors and tastes readily, might be packaged in this inorganic coke, melting the rock-slag ingredients to a fluid molten sla 9 385 slag chrough a small aperture, allowing the slag p to a steam jet, and blowing the slag in tiny ugh the air, whereby friction elongates the droplet read before it has time to solidify. These fine ds form the wool and are then collected and fabri ny forms of insulating products, cturer of rock wool has introduced a spinning ce of the steam jet, which is revolved at high speed . axis. The molten stream issuing from the forHhe outer section of the disk, whence it is violently ough the air in a manner similar to the action of et. dons are not exactly right, part of the original be cooled and solidified before it is drawn into nination of most raw wools will show fibers still .what is left of the original particle of molten slag. dified globules are known in the industry as "shot," fiduct. lants the wool is blown into wool rooms as it leaves These rooms vary greatly in size and construccm practice, however, requires a moving conveyerSome wool rooms have elaborate ventilating sysIfcas others have no such provision. The wool (the moving floor and is carried out of the room in a jf quite uniform thickness, the latter being regulated of blowing and the speed of the conveyer. As the rges, it usually passes under a heavy idler roll icr compacts it to uniform thickness. In some blanket, as it emerges, is sprayed with a liquid _crease its structural strength or to promote ease in ic various shapes into which it may be cut. intended for immediate fabrication are cut both ally and transversely by knives or revolving disks sizes required for batts to be used in wall insulation Studding. These may be covered on one or both sides i or moistureproofed paper. They are then packed "s for shipment. Wool intended for other types of .is usually gathered from the conveyer and sent to the r, after which the shot is removed. These fine, shotfare bagged for shipment as granulated wool for blowihe walls of houses already constructed. I or loose wool is also mixed with suitable binders d or molded into insulating board, pipe covering, or Mixed with day or bentonite and asbestos, loose aced wool is sold as insulation cement. Mixed with '" q form a paste, it can be formed around irregularly ^objects as an insulating cover. Loose wool as taken 'c conveyer is frequently placed between chicken wire Uath and sold in blanket form as insulation for sreamung units in furnace walls and on ducts and bridgings, ^petroleum refining for insulating process vessels and heat gers. Railway cars and annealing ovens offer ocher . Insulating board or blocks are made up to any spcciI size and thickness for stove or refrigeration insulation. Halation of houses against excessive heat or the escape of heat during the winter provides the greatest market niflcr.il wool. It has been found that mineral wool, ii. in thickness, has the same insulating value as 14 in. Ilow-pine lumber, 33 in. of plaster, 56 in. of brickwork, 1 in. of concrete. However, the best insulator of all is ; space, as illustrated by the vacuum bottle. The next /practically, is still air. In modern frame construction, "fyalls of houses contain a dead-air space between the outside thing and inside plaster separated into vertical panels by ^bidding. In masonry or brick construction similar dead ii found in che furring spaces. Even if all these dead-air were hermetically scaled, movement of air within each panel would occur, thus reducing its insulating value. But when filled with mineral wool, the original space is converted into millions of tiny air pockets entrapped by the interlaced wool fibers. The fibers thus prevent air currents or, in fact, any air movement. Mineral wool thus converts the dead-air spaces of house construction to still-air spaces. Danger Units THE TRAVELERS INSURANCE COMPANY ANEW and unique concept of driving danger in terms of "danger units" is introduced in a booklet entitled, "Lest We Regret," just issued by The Travelers Insurance Company. It is pointed out that energy increases progressively as the speed of a car increases, but that the increment in energy far outstrips the addition in miles per hour. Using the term "danger units" instead of "energy units" or "hidden forces" seems practical. In danger units or D. U.'s simple numbers tell chc facts about the death-dealing energy which rides with a person who goes too fast. The energy to be absorbed if a person strikes an object while running 25 mph is just the same as if he fell a height of 20.9 ft. For thousands of years men have been falling off their two-story dwellings and out of trees, where the fall is about 20 ft. It is possible to survive this impact, although it is just about the "shock limit" for the human body. Thus it was appropriate to call this quantity of energy which each pound of the body and each pound of the car carries at 25 mph, "one danger unit of energy.'' At 35 mph, the blows are twice as heavy. At 75 mph, they are nine times as heavy. In other words, the danger unit is mathematically equal to the energy developed in an automobile moving at 25 mpb, to a street width (35 to 40 ft) of actual stopping distance, to one "roll-over" in case of an accidenc, or to an 80-fc turning radius on a curve. The rate of speed and the relative danger units, therefore, are 25 mph for one D. U., 35 for 2, 45 for 3, 50 for 4, 55 for 5, 60 for 6, 65 for 7, 70 for 8, 75 for 9, and 80 for 10. In this way it is easy for a driver to visualize that at 50 mph he will need four street widths to stop, he will roll over four rimes in case of an accident, or make one fourch as sharp a turn as he could at 25 mph or one danger unit. McDonald Observatory UNIVERSITY OF TEXAS he McDonald observatory together with its T82-in. reflecting telescope, which was constructed by the University of Texas from the proceeds of a trust fund amounting to 800,000 left by the lace William J. McDonald, has just been completed and will be formally dedicated on May 5. Perched nearly 6800 ft on top of Mt. Locke in the Davis Mountains in western Texas, the observatory will be operated jointly by the University of Texas and the University of Chicago, which now operates the Ycrkes Observatory in Williams Bay, Wis. The telescope is the second largest reflector type in actual use in the world. It is exceeded in size only by the 100-in. in strument at Mt. Wilson. Both of these will be topped at some future date when the 200-in. Palomar telescope is completed. The contract for both the design and construction of the ob servatory and the telescope was let in 1933- The observatory structure was completed last year and the 3-con, 82-in. mirror, in February, after four years of grinding and polishing. The observatory itself is a cylindrical steel structure, 71 fc 58 451 He was a leading authority itches of engineering, including I'jsflcunutics, gas distribution, Engineering, bridge construction, S|pnrv dams, strength and testing BjrJ.and machine design. In the |)lc was well known for his work ationai Niagara Commission Htcxtbooks which were widely ' (tuntry. ^died in 193) basing been the arly every honor that could be |on him bv his fellow engineers, is' president of the institution of rs and the Institution of Meginccts and was an Honorary Jboth bodies as well as of the ijjcicty of Civil Engineers and The Society of Mechanical Engineers, aided the first Kelvin Medal, the for bestowed bv* British engineers. SyMemorial Committee will be |h any expression of incercsc by in the United States and ic ifjicul.irly pleased to have cheat ^Contributions may be sene to rer, Honorary Treasurer, 82 Victoria iS. W. 1, England. |ygiene Foundation ^Industrial Health > Bulletin ofinformative bulletins on praetiiginccring measures for combating disease is being issued by Air ijindation, -(400 Fifth Avenue, Pitts,-anonprofit organization fot rhe aj^pf industrial health. The first of lals with "Determination of Benzol ie Atmosphere'' and the second Ipscand Care of Respirators," ins are being prepared by members |undation`s preventive engineering ;1*nd other specialists. Prof. Philip vard School of Public Health, is Of the committee. Other members jfCook, Chicago; J M. DallaValle, in, D. C.; T. F. Hatch, member, Efew Vork; H. M. Nichols, Hyde S. C. Vessy, Cleveland; and Pittsburgh, lllctin on respirators points out that important use of "respiratory procee ds" is under working conditions itection is required intermittently, as fog-ouc operations, sweeping after ^ln removing cores from large foundry shoveling, screening, and handlingof ij-and the operation and maintenance ing equipment. cr bulletin describes the method of ig benzol vapor in the atmosphere, a f importance in the coking, steel, ve, fuel, and chemical fields. It lists and reagents required and describes lure for taking samples and for chcir either by a volumetric or a colonthod. References arc given as well tion as to where the necessary apiy be obtained. M.I.T. Offers Special Course in Strength of Materials have been completed to hold the sessions in Torquay, which is located or. the south coast of Devonshire. Additional information may be obtained from the Central Office of the SPECIAL summer program and confer I.E.C., 28 Vicroria Street, London, S W. 1. A ences on strength of materials will be held at the Massachusetts Institute of Tech nology for four weeks, beginning June 13, Foundrymen. to Meet at to cxccnd the application of concrete, steel, and wood through a knowledge of chcir character Cleveland, May 16-19 istics. The different aspects of the strength prob lems of these materials will be critically dis cussed by experts on the staff of the Institute supported by certain outstanding authorities from industry and various laboratories. Repre sentatives from chc Forest Products Labora tory, Madison, Wisconsin, and die American Lumber Manufacturers Association, Washing ton, D. C., will take part tn the lumber pro gram. Talks on concrete will be given by specialists of the Tennessee Valley Authority and of the Thompson Lichcncr Company, Boston. One of the series of lectures will be devoted ORE THAN forty technical sessions, M luncheons, and dinners arc scheduled during the 42nd annual convention of the American Foundrymen's Association which will be held in Cleveland, May 16-19. Items to be discussed include gray iron, nonferrous founding, foreman training, pactcrnmaking, refractories, job evaluation, steel, apprentice training, cost methods, malleable cast iron, sand research, materials handling, foundry safety and hygiene. Further information may be obtained from the secretary, Dan M. Avey, American Foundrymen's Association, 212 W. Adams Street, Chicago, Illinois. to a presentation of the known facts underlying chc scrength of steels and a comparison of Lehigh Inaugurates Annual these data with what is known regarding con crete and timber. Two all-day conferences at Anthracite Conference which representatives from industry will dis cuss the special features and new developments in these respective fields will conclude die program. The graduate school of the Insti tute will allow credit for nine unics ofadvanced study (nine units of A subjects) for the satis factory completion of this special course. Further particulars may be had from J. M. Lessells, Department of Mechanical Engineer ing, Massachusetts Institute of Technology, Cambridge, Nfass. URVEYING recent engineering develop S ments in the milling and utilization of anthracite, an Anthracite Conference, which is expected to become an annual affair, has been scheduled by Lehigh University for April 29 and 30. The conference committee, Herman Eckfeldt, chairman, and including the follow ing A.S.M.E. members, Allen J. Johnson, Fred V. Larkin, and W. H. Lesser, has arranged for presentation of L8 technical papers. These arc intended to focus interest on the rapid engineer ing progress heing made in production, dis Prominent Foreign Speakers tribution, automatic burning and consumer economy of anthracite. Additional reports at Applied Mechanics Congress of the utilization of ash, and the nonfuel uses of anthracite will also be included in the twoday discussion. Among the papers to be presented arc die THE FIFTH International Congress for following by A.S.M.E. members; "Some Applied Mechanics which meets at Har Practical Considerations in Connection With vard and M.I.T., Sept. 12-16, 1938, will beCombustion," by Allen J. Johnson; "AirCon distinguished by a general lecture on the ditioning and Refrigeration." by B. H. Jen strength properties of steel by Dr. F. Koerber, nings; "The Pulverization of Anthracite for Jirector of the Kaiser-Wilhclm-Insticuc fiir Commercial Use," by Martin Frisch, and Eisenforschung, Dusscldorf, Germany. A lec "The Relation of rite Type of Fuel to the ture on turbulence is scheduled to be given bv Cleanliness of Communities," by W. G. G. I. Tavlor, professor of the Royal Society, Christy. m which he will develop a new statistical theory of this baliling phenomenon. From France, Prof. J. Peres of the laboratory of Engineers Make Survey of lim'd mechanics of the University of Paris, will discuss methods of analogy in applied New England Industries mechanics, I.E.C. Plenary Meeting to Be Held in England HE EXTENT of modernization activities T in NewEngland manufacturing plants and the opportunities which exist for the further improvement of plant facilities and equipment are the keynotes of a survey which the New England Council and the Engineering $ocierics HE COMMITTEE of Action of the Inter of New England, Inc., of which the Boston Tnational Electrotechnical Commission Section, A.S.M.E., is an affiliated bodv, are has accepted the British National Commi tree'sconducting among 2500 New England manu invitation to hold the next plenary mcccing facturers. The survey, in the form of a scries in England, June 22-3-3. 1935. Arrangements ol self-aralvsis questions, will disclose rhe illWS jjiene Foundation Industrial Health Bulletin finformarivc bulletins on pracciincering measures for combating ftiisease is being issued by Air dation, 4400 Fifth Avenue, PittsJionprofit organization for the adt industrial health. The first of :1$ with "Determination of Benzol "t Atmosphere" and the second pc and Care of Respirators / * is arc being prepared by members 1'trions preventive engineering 1 ocher specialists. Prof. Philip ard School of Public Health, is the committee. Other members Q0k> Chicago; j. M, DallaValle, , D. C.; T. F. Hatch, member, "*ew York; H. M. Nichols, Hyde S. C. Vessy, Cleveland; and \ Pittsburgh. tin on respirators points out chat ifjportant use of "respiratory proeec* is under working conditions tion is required intermittently, as Jig-out operations, sweeping, after 1 removing cores from large foundry |Iiovding, screening, and handling of and the operation and maintenance ; equipment. bulletin describes the method of benzol vapor in the atmosphere, a ? Importance ia the coking, steel, %r fuel, and chemical fields. It lists }ind reagents required and describes hire for caking samples and for their either by a volumetric or a coiori- RcfercnccS arc given as well tian as to where the necessary apay be obtained. ,E. News