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By Barbara A. Thompson

A previously reported high-resolution method for the location of boron-rich areas in metallurgical and biological specimens was been adapted for general use on a routine basis. The rnetlzod utilizes neutron activation and autoradiograpizy. Alpha-particles emitted by boron nuclei upon neutron capture are recorded on a photographic emulsion. The resulting a-particle tracks show the location of boron-rich areas. Experimental techniques, interferences, and limitations of the method are discussed in detail. The method is most useful where there is marked segregation of boron. In this type of sample, the segregation can be observed when the nominal boron concentration is as low as 0.0006 pct. THE positive identification and location of boron-rich areas in metals is frequently of great interest in metallurgical work. Unequivocal identification is often difficult to make by conventional metallo-graphic methods. Recently, a method has been described which accomplishes this objective by neutron activation and autoradiography.l-3 The method can be described briefly as follows. Upon neutron capture, a -particles are emitted by boron nuclei according to the following reaction: ,Blo + n - ,a4 + 3Li7 + 2.4 mev The energy is dissipated as kinetic energy of the products. By irradiating a boron-containing sample in contact with a photographic emulsion and subsequently developing this emulsion, a-particle tracks are obtained whose location corresponds to the location of boron-rich areas in the sample. Two factors combine to make the reaction extremely specific for boron. The first is the unusually high (755 barns) cross section of boron for thermal neutron capture. The second is the higher neutron energy required to produce (n, a ) reactions in essentially all other nuclei except lithium. These two factors make the method specific for boron by six to seven orders of magnitude when a predominantly thermal neutron source such as the Brookhaven reactor is used. The reported limit of detection of this method is of the order of 0.01 pct B., The present work was originally undertaken to determine whether this limit could be lowered by use of a thinner emulsion. However, initial experiments showed that in order to use the method at all, it was necessary to reestablish the optimum experimental conditions in terms of the available irradiation facilities. It is the purpose of this paper to describe these experimental conditions in detail, to discuss the factors influencing sensitivity, and to evaluate several techniques for increasing sensitivity. EXPERIMENTAL A) Preliminary Experiments—The first measure-ments were made using samples of crystal oriented silicon steel containing various concentrations of boron. In the later experiments, samples of various high-temperature alloys such as M-252, hcoloy 901, Nichrome V, and so forth, were used. Faraggi, et al.,2 reported that the lower limit of sensitivity in this type of sample was about 0.01 pct B using nuclear emulsions of 50- u thickness. but that it should be possible to extend this limit by the use of thinner emulsions. Accordingly, we first used Kodak Auto-radiographic Stripping Film (Permeable Base) which has an emulsion thickness of only 5 µ. This was mounted on the metallographic specimens according to the technique described by Boyd.4 The emulsion remained in contact with the metal surface throughout exposure and development. Since the emulsion is transparent after development, the autoradiograph and metal surface can be viewed simultaneously and any correlation between film blackening and structure of the metal can be made directly with no problems of realignment. Because the silicon steel is readily attacked by moisture alone, it was necessary to apply a protective coating to the metal surfaces before mounting the emulsion. The coating was made extremely thin in order to absorb as few a-particles as possible. Boyd4 and Gomberg5 have discussed various plastics used for this purpose; however, none was sufficiently impermeable to prevent chemical attack of the steel during the developing process. This attack resulted in the production of gross chemical artifacts in the emulsion. It was, therefore, necessary to use the method of Wolfsberg and John6 as follows. A very thin (approximately 1 µ) coating of Plexiglas II was applied by dipping the sample in a 2 pct solution of Plexiglas II in dichloroethylene. Then, because the emulsion will not adhere to Plexiglas 11, a thin coating of Parlodion was applied in a similar manner using 2 pct Parlodion in iso-amyl acetate. No protective coating was necessary with the high-tem-

Jan 1, 1961

By J. Szekely, G. P. Martins

A formulation is given and a general analytical solution is presented for the problem of spherical phase growth in multicomponent systems. The results are valid for describing the rate of bubble growth in the absence of translational motion and, therefore, should be relevant to heterogeneous nucleation processes. Typical worked examples are given, which include bubble growth due to the simultaneous diffusion of hydrogen and nitrogen in molten steel, and the growth of CO bubbles in steel, due to the reaction: C + 0 = CO. The calculations predict that the presence of additional components would enhance the growth rate and also increase the absolute rate at which the individual components are transferred into the bubble. These findings should be relevant to degassing processes. THE problem of spherical bubble growth in the absence of translational motion is appropriate to the description of the heterogeneous nucleation and subsequent growth of gas bubbles while attached to a solid surface. Such problems are of considerable practical relevance to various vacuum degassing and steelmaking processes where bubble nucleation and subsequent growth play an important part in the overall reaction mechanism. A definitive formulation of spherical phase growth has been given in the now classical paper by Scriven1 and the analogous problem for solid phase growth has been discussed by Horvay,2 furthermore a thorough review of the relevant literature has also become available.3 All this previous work was concerned with one component or binary systems. The purpose of this paper is to show that the technique developed by Scriven may be generalized to alow the consideration of multicomponent systems. The results of this generalization would be particularly relevant, as gas bubble nucleation in the metallurgical systems previously mentioned frequently involves the simultaneous diffusion of several components. In the following a general formulation is given and typical worked examples are presented. FORMULATION Consider the growth of a spherical gas bubble due to diffusion in a quiescent liquid of infinite extent, as sketched in Fig. 1. The formulation of such problems requires the statement of the following conservation equations relating to the liquid phase: Equation of continuity Equation of motion Conservation of the diffusing species—Diffusion Equation. The following assumptions are made: a) The fluid is incompressible, quiescent, and of infinite extent b) The bubble is stationary, i.e., it undergoes no translational motion c) Spherical symmetry is observed throughout d) The mass diffusivity is constant e) Chemical equilibrium exists at the surface of the bubble, and any reactions occurring there are fast compared to the diffusion process f) Inertia and surface tension effects are neglected. Equations derived on the basis of these assumptions by previous investigators were found to provide a reasonable representation of bubble growth while attached to a surface in organic and aqueous systems4,5 For gas bubble growth in molten metal systems assumptions a) to d) chould hold reasonably well. The exclusion of chemical kinetics as a possible rate limiting step may not be universally valid, but should hold for many systems operating at high temperatures. The effect of hydrodynamic inertia may be neglected for moderate growth rates; finally, the assumption neglecting the effect of interfacial tension on the bubble growth was made for the sake of mathematical convenience; its inclusion would have required the use of quite cumbersome numerical techniques. While surface tension effects could be appreciable on the initial values of the overall growth rate, especially at low absolute pressures and in case of small bubbles, they are not thought to modify the relative effects present in multicomponent systems, the study of which is the objective of this paper. Within the framework of the above assumptions

Jan 1, 1970

By Peter L. Swanson

A microcrack process zone is frequently suggested to accompany macrofractures in rock and play an important role in the resistance to fracture propagation. Attenuation of surface waves propagating through mode I fractures in wedge-loaded double-cantilever beam specimens of Westerly granite has been recorded in an attempt to characterize the structure of the fracture process zone. The ultrasonic measurements do not support the generally accepted model of a macroscopic fracture that incrementally propagates with the accompaniment of a cloud of microcracks. Instead, fractures in Westerly granite appear to form as gradually separating surfaces within a zone having a width of a few millimeters and a length of several tens of millimeters. A fracture process zone of this size would necessitate the use of meter-sized specimens in order for linear elastic fracture mechanics to be applicable.

Jan 1, 1984

By F. A. Loving

This paper describes experiments which represent an effort to measure preciscly the pressure-time history in detonating condensed commercial explosives. The performance of explosives in mining has been a favorite subject for experimentalists and theorists for many decades. Much useful empirical information has been developed; but it has not yet been possible to predict, or even to account for, the behavior of explosives in mining on the basis of fundamental physical principals. A basic piece of information that would appear necessary for any rigorous analysis is the pressure-time history in the detonating condensed explosive. The experiments described here represent an effort to measure this relationship precisely in commercial explosives. THE EXPERIMENTAL METHOD The experimental method, first described by Cowan and Jacksonl has been extensively evaluated by Cowan and Balchan for relatively simple explosives. The experimental procedure involves the detonation of a layer of explosive between metal plates whose external surfaces are polished to a mirror finish (Fig. 1). Precise measurements of the deflection of

Jan 1, 1967

By D. M. Hausen

The amenability of a given vanadium ore to any given treatment depends largely on the mineralogic combinations of vanadium in the ore. Quantitative data on vanadium mineralogy provide not only an objective basis for selection of proper treatment, but also may eliminate many time-consuming amenability studies whose results are empirical, at best. Vanadium is distributed through the interstices of mineralized sandstone ores in the form of oxidized vanadates, reduced oxides, and silicates. Oxidized vanadates, e.g., carnotite, tyuyamunite, etc., are most readily beneficiated by simple acid leaching. Reduced oxides are more slowly solubilized, but relatively amenable to most acid treatments. The layered silicates, roscoelite, mixed layered mica-montmorillonite, and chlorite, are least amenable to most acid extractions, and constitute an assemblage of vanadium- bearing clays that are common to many sedimentary deposits. Vanadium is combined principally as layered silicates in the clay fractions of many sandstone ores. Mineralogic studies in this paper are largely confined to clay minerals, and to their amenability characteristics in low pH liquors.

Jan 1, 1985

By Frank A. Hill

A visitor to the Northern anthracite coal-field in 1844 wrote: " History and song have hallowed the valley of Wyoming, and everything pertaining to it seems wrapped in an atmosphere of romance." Song and history have since been almost forgotten in the rush of enterprise and business energy, while the invested capital which has built 160 colliery plants, producing last year 17,031,826 tons of coal and giving employment to 50,000 men and boys, lends an atmosphere the inspiration of which is the very sustenance of prosperity and progress. The fundamental cause of this great valley's financial strength, however, rests on the fulness of its mineral wealth. Its mountains surround and its cities are built upon anthracite coal. Its foundation, physically, financially and socially, is coal. Its geology has governed its growth and developed its greatness. In 1768, ten years, prior to the celebrated Wyoming massacre, two Connecticut Yankees, named Gore, settled near Wilkesbarre, Luzerne County, and, burning Pennsylvania anthracite in their blacksmith's forges, were the first to utilize it as a fuel. Its first use in the household was also at Wilkesbarre, where, in 1808, Judge Fell burned it in an open grate. Carbondale, Wilkesbarre, and Scranton were early recognized as the coal centers of the field.

Jan 1, 1887

By J. E. Powers, T. D. Taylor, N. E. Wood

A computer program has been developed to simulate a gas transmission 1ine operating under transient conditions. The program was developed by application of the basic mass and momentum balance equations. The nonlinear equations thus obtained were transformed by the method of characteristics and finite-difference techniques to make them suitable for machine computation. Three tests of the computer program were made. In each of these, the initial condition was assumed to be steady-state flow, the inlet density was held constant at the initial condition, and the outlet mass flow rate was varied with time. One test was theoretical in nature, but the others were made for direct comparison with actual field data. Results of the tests are presented in graphical form. INTRODUCTION Theoretical investigations of the transient flow of gas in long pipelines have been limited in number. In 1951, Olds and Sage4 developed a gaphical method of solving the nonlinear flow equations describing transient gas flow in a long pipeline. Research in this field at the U. of Oklahoma was initiated by Nelson1 in 1956. Nelson utilized a computer to solve numerical equations involving a lengthy trial-and-error procedure, and his results have been reported in the literature? It does not seem likely that Nelson's method can be extended to the analysis of transient behavior of pipeline networks; therefore, the investigation to be discussed in this paper was undertaken to improve and extend the previous work. The following discussion presents, briefly: (1) the basic differential equations governing transient flow, (2) transformation of these equations into a form suitable for machine computation. (3) role of boundary conditions in the calculations, (4) a very brief description of the computer program which was developed to simulate the pipeline and (5) results of tests of the computer program.

By John T. Grasso

This paper describes the computer-assisted development and implementation of new written examinations for persons desiring to become certified as underground or surface mine electricians in the State of West Virginia under the certification program defined by the WV Department of Mines and the Board of Miner Training, Education and Certification. The procedures used to develop and validate the new certification tests have simplified the administration of the new tests. Future developments in mine electrical work can also be easily incorporated into the certification program by augmenting the existing computerized pool of test questions prior to computer-production of future test forms. Most important, computerization now facilitates continual evaluation of the certification program, to contribute to greater safety in mine electrical work in West Virginia.

Jan 1, 1983

By J. M. Floyd

The theory, construction and applications of oxygen sensors employing high-temperature electro- chemical cells with solid electrolytes are briefly reviewed. The application of disposable probes to measurement of the oxygen potential in matte and slag baths in tin, copper, and nickel smelting operations is described. Examples discussed include end-point determination in smelting and slag-cleaning operations, pilot-scale investigations of process chemistry to assist in the development of smelting strategies, and measurements in operating smelters to improve the efficiency of operation.

Jan 1, 1984

By V. H. Wilhelm

The outstanding event in the California petroleum industry during 1931 was the continuance of curtailment of crude oil production, which directly reduced drilling and well repair activities. Although all objectives were not attained, a very close balance between supply and demand was maintained during the period of maximum requirements, but the decline in intercoastal and export shipments caused an overproduction during the last half of the year, which indicated that California production would necessarily suffer further curtailment after the end of the year. A new peak in potential crude oil production of 1,187,600 bbl. per day was reported in August and at the close of the year the California potential was 1,069,000 bbl. per day, the shut-in light oil amounting to practically 425,000 bbl. per day and the shut-in heavy oil amounting to about 150,000 bbl. per day. Fig. 1 depicts these conditions and also shows the production and curtailment situation since the inception of proration in California. The December, 1931, potential figure of 1,069,-000 bbl. per day was arrived at after the most careful deliberation by a number of committees, selected to check the potential of practically every well in the state. Continued overproduction in the first three months of 1931 and the inadvisability of building more storage, together with the inability to obtain the proper amount of curtailment in town-lot fields, such as Long Beach, Santa Fe Springs and Playa del Rey, prompted the major oil companies to inaugurate a price reduction in crude oil. This cut caused prices to reach the lowest levels since 1915, and instigated the formation of an oil sales agency, composed of independent operators, which is known as the Oil Producers Sales Agency. The purpose of this organization is to procure a market for its members at reasonable prices, advise them of market conditions and aid them in controlling the amount of oil available for sale. Marketing of oil produced by members began on June 1 and independents controlling" about 160,000 bbl. per day of production had become members by the end of the month.

Jan 1, 1932

By T. K. Smith

The comments contained in the discussion of the paper concerning the prediction of fracture gradients are of considerable interest, since the subject is of a very controversial and timely nature. It is regrettable and Fairhurst2 contradicts the author's statement in the third paragraph of Other Applications. These references create significant doubt that Eaton's Eq. 1 predicts fracture pressure during the injection of fluid into old wells. 3. No evidence is presented in this paper to support the author's Conclusions 2 and 3. While an empirical coefficient related to back-calculated field data is correlated with depth (Eaton's Fig. 4), there is no reason to suspect that this coefficient might be the Poisson's ratio of the various formations involved. 4. Until the field data supporting the empirical approach proposed by the author are presented and evaluated, the accuracy claimed in Conclusion 5 is without substantiation. References 1. Geertsma, J.: "Problems of Rock Mechanics in Petroleum Production Engineering", Proc., First Intl. Symposium on Rock Mechanics, Lisbon (1966) 585. 2. Haimson, B. and Fairhurst, C.: "Hydraulic Fracturing in Porous-Permeable Materials", I. Pet Tech. (July, 1969) 811-817. that the comments are those of a critic and do not offer an alternative and better method for the prediction of fracture gradients. Nevertheless, a reply is in order.

Jan 1, 1970

By R. H. Richards, A. E. Woodward

In Rittinger's Aufbereitungskunde of 1867 occurs (p. 195) the following table, which shows the rate of falling in water of fragments of minerals, of irregular shapes and of five different specific gravities: Diameter of particles in millimeters. 10 8 6 4 3 2 1 .5 Sp. Or. Velocity in meters per second. Auriferous silver, 16..9 .8 .7 .57 .5 .4 .29 .20 Galena,. ..7.5 .62 .55 .48 .39 54 .28 .20 .14 Pyrites,. ..5.0 .49 .43 .38 .30 .26 .22 .15 .10 Quartz,. ..2.6 -30 .27 24 .19 .17 .14 .10 .07 Coal,. ..1.3 .13 .12 .10 .08 .07 .06 .04 .03 With the purpose of extending this valuable table, to cover a larger number of minerals and sizes of each mineral, and of making it more easy of application in deciding upon a sieve-scale for any group of minerals, we have prepared the curves of velocity of fall of bodies in water shown in Plates I., XI., 111. and IV., using Rittinger's formula V= 2.44d(8 —1) where V= velocity in millimeters per second. " D = diameter of particles in meters. " 8 = specific gravity of the mineral. These curves embrace a large number of specific gravities, and for each specific gravity the relation of the diameter of the mineral particle to the velocity of its fall in water is given for all diameters and velocities used in practice. The second diagram is an enlargement of the lower left-hand corner of the first, the third bears the same relation to the second, and in like manner the fourth to the third. Plate I, therefore, covers the work of the coarsest jigging 2 inches in diameter; and under

Jan 1, 1890

By H. K. Livingston

THE first person to investigate intensively the vast field of surface phenomena and capillary effects was the eminent English scientist, Lord Rayleigh (1842-1919), who laid down most of the fundamentals of this subject. This work was greatly amplified by Irving Langmuir,1 who, in connection with research for the General Electric Co., spent 25 years on the study of the surface chemistry of films, finally receiving the Nobel Prize in Chemistry for 1932 in recognition of his work. At present, William Harkins,2 of the University of Chicago, is the world's foremost authority on surface-tension measurement and his independent work, when combined with that of Langmuir, resulted in the orientation con-cept of solubility and surface activity, which is now an important funda-mental in chemistry. The theory laid down by these men was first applied to practical considerations regarding petroleum reservoirs by F. E. Bartell,3 of the University of Michigan, in connection with an American Petroleum Institute research grant. The latest and most advanced application of Bartell's work is contained in an article published in 1935 by Allen Garrison,4 of Rice Institute, in which he relates Bartell's measurements to the ratio of oil to water produced by wells and shows the types of petroleum reservoirs where the effects studied by Bartell are significant. This article is intended as a minor extension of such work.

Jan 1, 1938

By J. F. Wolff

The iron formation of the Gogebic Range in northeastern Wisconsin and the northwestern part of the Upper Peninsula of Michigan, resembles that of the Mesabi Range in Minnesota very closely in lithologic character and the subdivisions and horizons that can be recognized. It contains numerous interbedded slaty layers and considerable intraformational conglomerate in certain horizons. In contrast to the flat dip of the Mesabi formation, the Gogebic dips steeply to the northwest at an average angle of about 70". It has a quartzite and siliceous slate foot wall and a hanging wall of conglomerate, graywacke and slate. The black and gray Tyler slate has been designated the hanging wall of the Gogebic iron formation in U. S. Geologicial Survey monographs, but between the true Tyler slate and the commercially important Gogebic iron formation, and apparently unconformably upon the latter, is a series 600 ft. or more thick of conglomerate, slate, graywacke, and cherty iron formation, the latter being of no commercial importance on the Gogebic Range as far as now known. This series is probably that described as the "Capps" on the eastern Gogebic by the Michigan Geological Survey. The Gogebic iron formation proper can be subdivided into three main horizons, a lower cherty and an upper cherty with a banded or slaty horizon between them, corresponding to the three lower horizons of the Mesabi. Several minor subdivisions can be made of these major ones. Orebodies occur in all three horizons of the Gogebic series and in some places ore is developed across practically the entire series. Dikes and Sills The Gogebic iron formation has been intruded most intricately by basic dikes and sills, most of the former pitching east but some pitching west. One very extensive sill is intruded near the base of the lower slaty or banded horizon, in the formation known locally as the Yale slates. One extensive bedding or strike fault is associated with this sill and a great many transverse faults occur at different places along the Range. The combination, or association, of steep dip, faults, dikes and sills has produced conditions very favorable for the development of orebodies through the leaching, oxidation, and consequent concentration effected

Jan 1, 1925

By Edward Steidle

It has been said that "the command of nature has been put into the hands of man before he knows how to command himself," and what we see about us gives particular emphasis to this observation. If this condition be granted, the vaunted boast of school and college, of the institution that had the training of this generation, and of its fathers, and of its grandfathers, the boast that education is a "preparation for life," stands exposed as a hollow claim, or as a ghastly, cynical conception of life, or else education has fallen far short of its intentions. It has been evident for some time that education was not meeting the fullest expectations of society. In recent years there has been a deal of speculation indulged in by both laity and faculty in regard to American education and American civilization, and some few and sporadic changes have been effected. Today, however, there is no longer time for mere hypothetical considerations; we are faced with certain definite facts and confronted with obvious conditions that will not wait for fine-spun theories. If educators do not put their house in order, someone else will do it for them. The trends in mineral industries education must be in harmony with this general realignment that is today visible on the educational horizon, and only as these trends are in conformity with this movement can they be called sound. Two questions, then, confront mineral industries educators: (1) What are the trends in mineral industries education, and (2) how do these trends correlate with the major educational movements of the day? Scope or Mineral Industries Education Before launching into these particulars, it might be well to define the scope of mineral industries education and to consider its present position. Mineral industries education embraces three main types of work: 1. Earth Sciences and Geography.—Geology, mineralogy, geography— courses basic to all mineral industries and to the humanities. 2. Mineral Engineering.—Mining, petroleum and natural gas—dealing with mineral producing industries. Application of earth sciences and all types of engineering to exploitation of natural mineral resources.

Jan 1, 1934

By K. U. Snowden, J. N. Greenwood

CRACKS which form in lead exposed to fluctuating stress frequently follow a rectangular pattern. It is well known that under ordinary atmospheric conditions these cracks are intercrystalline. On the other hand after fabrication the crystal grains in lead are in general irregular polygons. The observed facts appear to be mutually contradictory. Re-examination of some lead failures has confirmed that the rectangular cracks are intercrystal- line. It follows therefore that under fluctuating stress some of the grains lose their irregular outlines and become approximately regular polygons of cubic type. G. R. Gohn and W. C. Ellis* suggest that this is due to recrystallization during the life of the part, in such a way that the new grain boundaries are aligned at 45 deg to the longitudinal strain prior to the formation of the fatigue crack. Experiments at Baillieu Laboratory—Some recent experiments carried out in the Baillieu Laboratory in conjunction with the Broken Hill Associated Smelters have thrown some light on this transition. A test piece of pure lead was polished chemically

Jan 1, 1959

By M. J. Scoble, W. J. P. Leigh

This paper aims to characterise the forms of slope instability incident in surface coal mines in Britain. These are related to observed controlling factors, with particular reference being given to slope geometry and structure. The work is based on specific data collection programmes considering actual stable and unstable mine slopes. Reference is made to field examples.

Jan 1, 1982

By R. C. Gifkins

The ideas expressed in this paper interest me very greatly, partly for their own sake and partly because they are very close to some speculation I have recently made concerning grain boundary diffusion. This is in a paper describing an extension to Mott's "island" theory of the grain boundary, to be published shortly.37 The facets or islands of good fit are identified in terms of specific crystallography, as in the model put forward by Brandon et al., and the bad fit between them is suggested to be interlinked "channels" of relaxed vacancies, associated with grain boundary ledges.

Jan 1, 1969

By Subhas G. Malghan

The response of feldspar flotation to tallow diamine dioleate collector in the presence of sulfuric acid is studied using batch flotation experiments. Application of this nonhydrofluoric acid (non-HF) reagent system in the flotation of mineralogically and chemically different feldspar ores is compared with that of the conventional hydrofluoric acid system. The dependence of flotation recovery and concentrate grade on feed particle size distribution, conditioning time, pulp density, and pH, combined variation of collector and acid addition rates, sodium hydroxide concentration in the collector solution, and initial pulp pH Prior to conditioning is studied. The results have been discussed in relation to applicability of the non-HF system to plant trials, and the nature of the collector adsorption in the selective flotation of feldspar.

Jan 1, 1982

By B. Rao Pothini, Hilmar A. von Schonfeldt

One of the key elements essential to a productive and uninterrupted longwall mining operation is roof control. In several of the Island Creek Coal Company's mining sections, polyurethane has been infused 80 into strata to control severe roof failures in the face and gate entry areas. To date about 50,000 kgs (110,000 lbs) of the chemical have been consumed in a number of applications. Roof-to-floor convergence 60 and differential roof sag have been monitored to determine the need for polyurethane infusion and also to evaluate roof stability following the infusion. Stratascopic observations of the roof formed the basis 40 for confirming the need and also for estimating the required quantities of polyurethane. Both chemical infusion and roof control monitoring techniques have been applied successfully under very adverse roof 20 conditions; substantial production benefits have been realized. Operator acceptance of the system has been very good.

Jan 1, 1981