Shop Practice Research Articles

A Novel Printed Circuit Board Laminate for High Frequency Electronics

A novel PCB material that is advantaged at the 10-100+ GHz range has been developed. It consists of a 3 layer laminate, nominally with a total thickness of 140 microns, and individual laminates can be stacked to make multilayer boards. The outer two layers of the laminate consist of the polymer Topas, 50 microns thick and the middle layer is Corning’s ribbon alumina, 40 microns thick. For brevity, the laminate is called “TAT”. The permittivities of the Topas and alumina are 2.5 and 10 respectively, and that of the 50/40/50 TAT laminate is 3.2 in a direction transverse to the plane of the laminate. The individual loss tangents are about 0.0002, and the loss tangent of the TAT laminate has about the same value. Thus, TAT has significantly lower loss with a lower effective permittivity than other PCB materials currently available. These dielectric properties have been measured experimentally at 10 and 15 GHz. The permittivity and loss tangents can also be predicted accurately using extremely simple analytical formulae. This makes predicting the properties of TAT structures with different dimensions very easy. A TAT strip line has been modeled and found to have an effective permittivity of 2.3. The machining of TAT is somewhat incompatible with conventional PCB shop practice. However, laser drilling and cutting are perfectly practicable. In-house processes have been successfully developed, and an external vendor has also developed these capabilities. Copper sheet adheres strongly to the TAT, and the conductivity of the resulting traces is high. Boards for a 77 GHz radar demonstrate the manufacturability of TAT. Mechanical testing of TAT has been carried out, and the measured flexural modulus and stress at failure compare well with calculations. Environmental tests at 80 °C and 80% humidity indicate that TAT is quite robust. Moreover, it is quite possible that TAT itself may satisfy the UL94 criteria, since the alumina may act as a flame retardant. The feasibility of loading Topas with ceramic or fluoropolymer powders to reduce flammability has been investigated, and it has been found that the addition of these powders causes negligible dielectric loss. In summary, laminates of this type are plausible extreme low loss candidates for PCBs for very advanced applications such as 5G and 6G devices.

Online Shop Transaction Analysis View From Sharia Compliance (Case Study Of Faculty Students Economy And Business Islam Iain Padangsidimpuan )

This research is motivated by the many occurrences of incompatibility of goods ordered with those sent in online shop transactions among students of the Islamic Banking Study Program FEBI IAIN Padangsidimpuan. So the purpose of this study is to find out the perceptions of students of the Islamic Banking Study Program FEBI IAIN Padangsidimpuan about online shops , the form of online shop practice for students of the Islamic Banking Study Program FEBI IAIN Padangsidimpuan, and the concept of online shop seen from fiqh . This research uses descriptive qualitative analysis method . Sources of data used are primary data and secondary data, these data were obtained from information researchers by using direct interviews with research subjects. While the data analysis technique uses data reduction, data presentation, and drawing conclusions. From the results of the study, it can be seen that the perceptions of students of the Islamic Banking Study Program FEBI IAIN Padangsidimpuan about online shop transactions has both positive and negative sides. The positive side can make it easier for students to make buying and selling, save time, energy, can be done using a smartphone . While the negative side is shopping online , not being able to try the goods directly, incurring shipping costs, delays in delivery times, and rampant fraud.Keywords: Buying and Selling, Online Shop, As-Salam

In situ estimation of equivalent porosity and strength of aluminum die-casting floor panel by simple loading test and finite element method

A simple estimation method of equivalent porosity and strength of scrapped aluminum die-casting floor panel is suggested in which various defects like pores can be allowed. During shop practice of processing die-casting parts, equivalent porosity is evaluated by the ratio of linear stiffness from the simple test to the analytical stiffness value. Porosity equation is derived from the inclusion theory. Then using Mori-Tanaka method the porosity value is used to find an elasto-plastic stress-strain curve for the porous material. In this paper Hollomon equation is used to describe the strain hardening effect of the die-casting material. Finally, the stress-strain curve for the porous material is used to calculate strength of die-casting part that captures the nonlinearity of the porous material. A facility die-casting floor panel is chosen to verify the proposed method. The result is accurate and adequate to the test result.

S2010202 九州大学工学部旧生産機械工学科の工作実習教育([S201-02]技術教育・工学教育(2),技術と社会部門)

This study aims to realize the preservation and utilization of machine tools which are being kept by the Kyushu University Museum and had been used for engineering education on machine shop practice of the former Department of Mechanical Engineering, Production Division, faculty of engineering, Kyushu University, from the era of establishment of the university (1910s) to the campus relocation in 2005. In the present report the curriculum of the engineering education and the contents of the subject of machine shop practice in this department, including the other related department on mechanical engineering in the university, are introduced. After the feature of the education program of machine shop practice which was developed by this department (Production Division) is described, it is shown that the education program is still growing with keeping the "spirit of the Department of Mechanical Engineering, Kyushu University". Finally, it is concluded that the machine tools which are being kept in the museum are very important for the histories of technology and engineering education.

Workload control in unbalanced job shops

Workload control (WLC) has been developed as a production planning and control approach for job shop manufacturing. By balancing loads across work centres, WLC anticipates the fact that multiple work centres may become potential bottlenecks in the short term. This approach is generally tested in job shop models that assume equal utilisation levels for all work centres, which will create maximum bottleneck shiftiness. However, job shop practice clearly shows differences in utilisation levels, which means that some work centres can be seen as non-bottlenecks, having protective capacity. This study investigates the effect of different levels of protective capacity on the performance of state-of-the-art WLC release methods. More in detail, it shows how the level of protective capacity interacts with the influence of workload norms at work centres. Despite the fact that WLC has been developed for highly balanced utilisations, results indicate that WLC could also be effective in unbalanced situations. However, norm setting requires careful attention. Disregarding the norms of non-bottleneck work centres, a common sense approach, might strongly deteriorate performance when the level of protective capacity is not sufficiently high. Contrarily, tighter norms for non-bottleneck work centres are shown to perform better in this situation.

Integrating a Machine Shop Class into the Mechanical Engineering Curriculum: Experiential and Inductive Learning

Research has demonstrated that inductive learning promotes deep knowledge structures, critical thinking and intellectual development. Industrial employers seek graduates with integrated knowledge and hands-on skills. This paper shows how a project-oriented machine shop practice course has been integrated with other courses, following an active and inductive learning model. Specific projects included a fast-return actuator, a simple acoustic guitar, a compressed-air engine and a catapult. These projects were chosen and executed to interface with concurrent and future courses, adding depth, ownership, enthusiasm and an experiential basis for the entire learning experience. Assessment data indicate high course value and support for future coursework. This model transforms the traditional, deductive learning model into inductive and active learning.

Influence of thickness size in sheet metal forming

A new approach on the influence of sheet thickness and material plastic properties on the limit strains in thin sheet metal forming is developed, using the strain gradient model that predict the local necking onset from initial thickness imperfections. As a result of the analysis, the definition of a roughness concept parameter is presented: the initial roughness profile inclination to thickness ratio parameter. Also, the critical normalized strain gradient at the onset of local necking can be calculated from the initial assumed roughness profile. A brief review of stretch forming of sheet metal, the diagrams and the limiting strain curves for local necking, FLC, and the limit strain theories are presented. The main characteristics of the sheet metal forming processes are also identified and are based in the press shop practice. The limit strains for different thickness sizes are obtained using the present model and a numerical code developed by the author. Present theoretical model produced reasonable predictions about the influence of thickness size on the FLC.

The Details of Shop Practice and Method of Instruction for Manual Training in the Textbook Authorized by Department of Education for Japanese Normal School

The Details of Shop Practice and Method of Instruction for Manual Training in the Textbook Authorized by Department of Education for Japanese Normal School

The peak load minimization problem in cyclic production

The objective of this study is to determine a production schedule for a set of jobs so as to minimize the peak load for the entire planning horizon given the production duration and the cyclic frequencies of the jobs. We refer to this problem as the peak load minimization problem (PLMP). An efficient heuristic, viz. Proc. PLMP, is proposed to solve such class of problems. There are two parts for the Proc. PLMP: a greedy procedure that secures an initial production schedule and a schedule smoothing procedure that performs a local search to reduce the maximal load. Numerical experiments verify that Proc. PLMP is efficient, since its run time is of cubic order of the problem size, i.e., it is approximately an O( n 3) algorithm. A major application of Proc. PLMP is to test the feasibility of a given set of a solution for the Economic Lot Scheduling Problem using the extended basic period approach. Scope and purpose The most prominent model for cyclic production is the economic lot scheduling problem (ELSP) in which n products are produced in lots of different sizes and, thereby, require different cyclical patterns. Under the extended period approach for the ELSP, there are two major problems in its cyclic production schedules. First, feasibility test of a given set of multipliers for a specified length of the basic period is a very hard problem, and second, the basic periods are typically unevenly loaded. Cost optimization, feasibility test as well as good shop practice, require the balancing of the loads on the basic periods. This can be achieved by minimizing the maximal load, which gives rise to the peak load minimization problem (PLMP) treated here. The problem is shown more complex than NP-hard. In order to solve the PLMP, we propose an efficient heuristic, Proc. PLMP. Proc. PLMP has been tested on problems of up to n=80 products, and it runs in cubic order of the problem size. Proc. PLMP also demonstrates its successful application to solve the feasibility test problem for the ELSP.

A RUNNER–GATE DESIGN SYSTEM FOR DIE CASTING

Various analytical finite element method (FEM) tools have been developed for flow processes, including die casting, but they only give information about whether the predetermined die design is correct. Current shop practice uses trial-and-error methods to determine new die designs. This article describes development of a computer-aided die design system for die casting. The computer-assisted design (CAD) system was written using Auto LISP with a personal computer. This system was developed to present algorithms for automation of die design, especially a runner–gate system using three-dimensional geometry. This system quantifies practical knowledge and experiences in die design as the formulating procedure. The system allows engineers to make automatic and efficient designs and it will result in reduction of required expenses and time. The system is composed of selection of cast alloy and product design, and uses the runner–gate design. In addition, specific rules and equations for the system are presented. An example is applied to a cap-shaped casting using the proposed system.

Practical Education for Integrated Machine Production from Design and Drawing to Manufacturing by Machine Shop Practice

In response to the reduction in the numbers of instructors, machine shops and hours allotted to students for machine shop practice at universi-ties, a system for efficient production education has been sought. Currently, production education spans a broad range of knowledge encompassing technical subjects from design and drawing to manufacturing. Hence, a practical education system which integrates the sequence of production processes is desired. In this study, we applied such a production process and used the example of a small jack, specially devised for use in practical training, as a production target to carry out all the tasks involved from design to manufacturing

Custom Design, Engineering Guarantees, and Unpatentable Data: The Air Conditioning Industry, 1902–1935

Custom Design, Engineering Guarantees, and Unpatentable Data: The Air Conditioning Industry, 1902-1935 GAIL COOPER Factory air conditioning appeared in 1902 as an industry dominated by custom design, and air conditioning remained that way for nearly thirty years. Each installation was unique, specially designed to fit a particular set of circumstances. Thus Carrier Engineering Corporation assured prospective customers in 1921 that “it is customary for engi­ neers who specialize in the design of such equipments to treat each problem individually and develop the most efficient equipment for the specific requirements of the client.”1 This approach to production established the overriding importance of engineering expertise within the industry, and the resultant centrality of technical knowledge to business success conferred on engineers both a shaping and controlling power over the emerging technology that was unbroken until the appearance of mass production. Custom design has been less well studied than mass production.2 Perhaps that neglect stems from an association of tailor-made products with a bygone era of craft production. Custom production may seem a historic relic, superseded by mass production. That sense of the new pushing aside the old appears as early as 1832 when Charles Babbage made a distinction between “making” and “manufacturing.”3 In his Dr. Cooper, assistant professor in the History Department at Lehigh University, is working on a history of air conditioning in the United States. She is grateful for the assistance of Dr. Anne Millbrooke and United Technologies, as well as the help provided by the staff of the Cornell University Archives. In addition, a Junior Faculty Fellowship from Lehigh University greatly facilitated access to archives and is acknowledged with thanks. 1 Weather Vein 1 (May 1921): 42. 'See David Hounshell, From theAmerican System to Mass Production (Baltimore, 1984); Otto Mayr and Robert C. Post, eds., Yankee Enterprise: The Pise of the American System of Manufactures (Washington, D.C., 1981); and Merritt Roe Smith, Harpers Ferry Armory and the New Technology: The Challenge of Change (Ithaca, N.Y., 1977). 'Martin Campbell-Kelly, ed., The Works of Charles Babbage: The Economy ofMachinery and Manufactures (London, 1989), 8: 85-86.© 1994 by the Society for the History of Technology. All rights reserved. 0040-165X/94/3503-0002$01.00 506 The Air Conditioning Industry, 1902-1935 507 discussion of Henry Maudsley’s work for the British navy, he describes a system of “making” that included the production of single-item goods with general-purpose tools to the specifications of the client at a relatively high cost. This description of making, or custom production, and the language to describe it prevailed for nearly a century. In 1914 Frederick Halsey, longtime editor of American Machinist, self-consciously used the same terms in his machine shop text to distinguish between the work of the shop and the work of the factory.4 When they sat down to write their own book on shop practice in 1935, Joseph Wickham Roe and Charles W. Lytle borrowed heavily from Halsey and reproduced the “making” and “manufacturing” distinction, but this time with a difference.5 Substituting the term “building” for “making,” their characterization of custom production focused less on the methods of production and more on the distinctive economic and social relationships that flowed from its practice. “The two processes of production,” Roe and Lytle wrote, “from initial sale to final acceptance follow different courses.”6 Custom design pivoted on a direct relation­ ship between buyer and seller, devolving on the engineer an important role from beginning to end. In this system of production, according to Roe and Lytle, “the sale precedes the building and even much of the designing, and the engineer is intimately concerned in the selling as he must convince the purchaser of the superiority of his design.”7 Their description of custom production in all its commercial trappings vividly depicts the features of a vital system of production rather than the shadowy outline of a dying craft. Roe and Lytle’s assessment is useful not simply for their sensitivity to the economic facets of custom production but, more important, for their reportage of a modern variant of the building tradition. They conceded that “building methods will always have their place...

How far from Japan? A case study of Japanese press shop practice and management calculation

This article reports the results of a case study of Japanese press shop practice and calculation. In Japanese shops, the balance between physical and financial calculation is biased very strongly towards the physical; orthodox Western cost accounting is completely absent. The bias in the forms of calculation is associated with an inter-process perspective on production and with a commitment to continuous improvement. On this basis, the article then takes up the issue of Japanization by examining the conditions which would have to be replicated if Western press shops were to become like Japanese press shops. Effective Japanization would require changes in the form of calculation, a new management cadre and a level of workforce commitment which is probably neither possible nor desirable in the West.

The Michelson Era in American Science: 1870–1930

The articles in this volume relate, in one way or another, to a single experiment: the Michelson-Morley ether-drift experiment of 1887. About one-half of the articles in the collection are based on papers delivered at a two-day symposium The Michelson Era in American Science: 1870--1930,'' held a Case Western Reserve University in Cleveland, Ohio, 28--29 October 1987, commemorating the centennial of the experiment. The Michelson-Morley experiment was designed to detect the motion of the earth through the luminiferous ether. At the time, physicists did not question the existence of the ether. The experiment, like many physical probes of nature, was simple in conception, yet uncompromisingly demanding of the art of contemporary craftsmanship. The state of the mechanical arts and its relationship to the pursuit of physical science in late nineteenth- century America is well documented in Section I, which also addresses the more general question of the link between state-of-the-art shop practice and engineering theory.

Calculation of the forming limit diagram

A mathematical model is presented to help understand sheet metal deformation during forming. The particular purpose of this model is to predict the forming limit diagram (FLD). The present model is an extension of a previous analysis by Jones and Gillis (JG)[1] in which the deformation is idealized into three phases: (I) homogeneous deformation up to maximum load; (II) deformation localization under constant load; (III) local necking with a precipitous drop in load. In phase III, the neck geometry is described by a Bridgman-type neck. The present model extends the JG theory, which was applied only to the right-hand side (RHS) of the FLD. The main difference in treating the two different sides of the FLD lies in the assumptions regarding the width direction deformations. For biaxial stretching (the RHS), the minor strain rate is assumed to be homogeneous throughout the process. However, for the left-hand side (LHS) of the FLD in the critical cross section, the minor strain rate is taken to be proportional to major strain rate. This is a critical difference from the JG approach and permits the LHS to be computed with good accuracy. Another important difference between this and the JG analysis is a more realistic neck geometry. At the inception of phase III, JG matched the phase II sheet thickness at the center of the neck, that is, at its minimum cross section. Here, the phase III neck matches the phase II sheet thickness at its ends, that is, at its maximum cross section. Although this may seem a minor point, it greatly improves the geometrical concept involved. Both the actual neck geometry and the criterion for determining the limit strain are modified from the earlier analysis in order to agree more closely with actual press shop practice. Results from this analysis are compared with the experimental ones for aluminum-killed (AK) steel and three aluminum alloys. These results are also compared to other theoretical calculations of the forming limit for AK steel. It is apparent that the present model is best. Unlike the other types of analyses, the present model predicts the limiting strain states for several materials very accurately without any adjustable parameters. This is certainly an unprecedented result. Using the mathematical model, the effects of varying material properties are studied. The properties considered are the strain-hardening exponent,n, the strain-rate sensitivity parameter,m, and the plastic anisotropy ratio,r, The important influence of these material properties upon the formability (level of the FLD) is affirmed.

Superpower: The Making of a Steam Locomotive by David Weitzman

TECHNOLOGY AND CULTURE Book Reviews—Labor and Technology 917 Superpower: The Making of a Steam Locomotive. By David Weitzman. Boston: David R. Godine, 1987. Pp. 107; illustrations. $19.95. David Weitzman, author of two popular guides to industrial ar­ chaeology, has now written and illustrated a book describing the de­ sign, construction, and testing of a locomotive. A large-format volume (IDA by 131/4), handsomely produced by David Godine, Superpower tells the story of the building of the first “Berkshire” class steam locomotive, a powerful 2-8-4 freight hauler. This story is told from the perspective of Ben, who in 1925 turns eighteen and goes to work at the Lima Locomotive Works in Lima, Ohio, where his father and grandfather already are employed. Readers learn about locomotive building by following Ben through an informal apprenticeship, which includes stints in the drafting room, patternmaking shop, molding floor and foundry, machine shop, and erecting shed. A fictionalized but primarily factual account, Weitzman’s story builds on extensive research and interviews, including an interview with Charles Schnell, Lima’s shop foreman in the 1920s. Although historical fiction is usually not reviewed in this journal, Superpower constitutes a unique primer on its subject and could be consulted profitably by anybody wishing to know something about the manufacture of heavy machinery. Indeed, Weitzman’s story ex­ plains aspects of shop practice about which even historians of tech­ nology may be somewhat hazy. How, for instance, are large castings made without introducing weak spots owing to uneven cooling of the molten steel? How were large plates riveted? How do designers of large, complex devices take advantage of metallurgical knowledge concerning the different properties of various kinds of steels? Weitz­ man’s book clearly answers these questions and many more. Because the author has immersed himself in early-20th-century technical lit­ erature, his story is also a reliable guide to the shop practice and methods of the period. Weitzman aims his book at the general reader but shares an agenda increasingly dear to scholars. This is the close study of the specifics of skill and of the work process, a project to which numerous disci­ plines are now contributing. Superpower can be linked, for example, with Working Knowledge: Skill and Community in a Small Shop (Chicago, 1987), a study by sociologist Douglas Harper, who has employed the ethnologist’s techniques to analyze the work and life of a small-town jack-of-all-trades named Willie. The knowledge commanded by Willie enables him to repair almost all of the machines on which his neigh­ bors in his upper New York State community depend for survival. Weitzman’s book also brings to mind The Age of Manufactures 1700— 1820 (New York, 1986) by Maxine Berg, an economic historian who, with a very different topic, also illuminates the linkages among work­ ers’ skills, the tools and machines they use, the products of the work process, and the social relationships impinging on the workplace. Fi­ 918 Book Reviews—Labor and Technology TECHNOLOGY AND CULTURE nally, Weitzman’s study recalls a recent T&C article by Laurence F. Gross, “Wool Carding: A Study of Skills and Technology” (October 1987), which adroitly documents the subtle connections between skill levels and technological change. Gross shows that management-pro­ moted deskilling could increase skill requirements as well as decrease them, a point skilled workers like Ben’s father and grandfather at the Lima works would no doubt have acknowledged. Historians interested in the new scholarship on work will want to consult studies like those of Gross, Berg, and Harper, but they will also find Weitzman’s story about building a locomotive enjoyable and instructive. Better than many scholars, in fact, Weitzman evokes the specifics of a world of production now largely lost. Moreover, in tack­ ling the subject of work wholly from the perspective of those who did it, he forcefully emphasizes the importance ofwhat Harper aptly labels “working knowledge.” As a brief and popular account of skill as re­ siding both in the hands and in the head, Superpower is a valuable contribution. Joseph J. Corn Dr. Corn is a senior lecturer in the Department of History at Stanford University, where he...

'An Academy for Doing'; I: The Accademia del Disegno, the Guilds and the Principate in Sixteenth-Century Florence

In January 1563, the Florentine Accademia del Disegno was formally granted a constitution by its nominal capo (head), Duke Cosimo de' Medici. It seems appropriate that the driving force behind the formation of the Academy should have been the first great historian of the visual arts, Giorgio Vasari (the absent and ageing Michelangelo, hero of Vasari's book, had been proclaimed joint head with Duke Cosimo). Effective power, however, lay with a Ducal representative, the luogotenente, a position to be occupied, not by a professional artist, but by a lay person 'of rank and dignity': throughout 1563, and exceptionally for the following year until the Feast of St Luke in October 1564 this post was filled by Vincenzo Borghini, a personal friend of Vasari's, scholar, historian, and, as prior of the Ospedali degli Innocenti, an already experienced administrator. By harnessing the power of the Medici prince to this new organisation, the artists of Florence had created a new type of 'art institute', public yet strictly belonging neither to state nor civic life. Similarly odd, quasi-official foundations were to be made in Rome, Paris and London within the following two centuries, but the early development of the Disegno does not entirely conform to the model of the later academies, for in 1571, only eight years after the initial foundation, the then luogotenente, Jacopo Pitti, petitioned the Medici Grand Duke on behalf of the membership. He asked that painters should be released from the obligation to belong to the city's Guild of Doctors and Apothecaries (the Arte dei Medici e Speziali), to which they were formally bound, and that sculptors might be similarly released from the Fabbricanti, a conglomerate guild which by that date had swallowed up the old Maestri di Pietra e Legname (Masters of Stone and Wood). Pitti's letter contained more than a simple request for manumission from the guilds of Florence, however. It included a further petition to set up a magistrature to try civil cases, nothing less than a guild tribunal to arbitrate disputes between artist and artist, or artist and client. The Medici fiat is recorded beneath the copy of the letter preserved in the Florentine Archivio di Stato. A committee of reform was convened to which two of the most prominent founder members, Vasari and Bronzino, were nominated and, by the following year, the Accademia del D segno was incorporated into the Florentine Guild system. In the modern literature on the Accademia, this d velopment has been interpreted in two contrary senses. For Nikolaus Pevsner, stressing the uphoria of a Vasari who, in letters of 1563, spoke of the academy as a potential 'university' (studio or sapienza), the making of what might be called an academic guild in 1572 represented a confused betrayal of the original aims of the institution. Though Pevsner's view was partly based on the mistaken assumption that Vasari had withdrawn from the affairs of the Academy at the time of the change, it does not stand or fall by this. Rather, Pevsner contrasted two sets of regulations, the Capitoli of 1563, which, he claimed, represented a radical break with guild practice, and a revised set of Statuti (1585), which, while largely taken up with matters of procedure and the election of officers, contains a batch of rules relating to the location of workshops, the contractual obligations of masters and apprentices, and some curious l gislation on the signing of works of art; these Pevsner correctly pointed out were indistinguishable from those of a guild. B contrast, the 1563 Capitoli had laid down provisions for an educational programme. Young artists were to have been visited in the workshops of their masters and encouraged by members of the Accademia. Regular lectures on mathematics were to have been instituted, and anatomical demonstrations periodically held at the hospital of S. Maria Nuova. It is easy to see in these measures an embryonic and properly 'academic' curriculum which, while not yet attempting to replace workshop training by establishing the hegemony of a central school, was nonetheless designed to enable academicians to intervene strategically in shop practice. As for the lectures, they literarily institutionalised the Albertian commonplace that the proper exercise of painting, sculpture and architecture depended on familiarity with certain kinds of theoretical knowledge normally associated with the practice of the Liberal Arts.

Feasibility of Polysulfide Detoxification of Concentrated Waste-water

Abstract Collecting of concentrated cyanide solutions in electroplating shops is quite a common occurrence. These accumulations of 4.5 to 9.0 cu m volume, which may be collected over a period of years, are usually in the concentration range of 1 to 3 per cent cyanide and present considerable dangers as they are stored on-site or transported for treatment or disposal. Common technologies available for the treatment of cyanide-containing wastewaters are generally not applicable to concentrated cyanide solutions, and some special technologies which could be applicable, usually show high capital costs and/or complexity of operation which render them unsuitable for smaller plating shop practice. In recent years, considerable work has been carried out to investigate a reaction of cyanide with polysulphide to form relatively innocuous thiocyanate. However, this reaction has been studied_only for cyanide solutions of low concentration (less than 100 mg/L CN-). This study was undertaken to investigate the feasibility of using the cyanide-polysulphide reaction to detoxify concentrated cyanide solutions (e.g. 2% CN-) and to investigate the initial kinetics of the cyanide-polysulphide reaction. It was found that the cyanide-polysulphide reaction is moderately exothermic and proceeds very rapidly both at room temperature and at 3°C. This process was capable of reducing cyanide concentrations to non-detectable levels within two weeks at a cyanide-to-polysulphide-sulphur ratio of 1:2 by weight. It was also found that the initial reaction rate kinetics of the cyanide-polysulphide reaction in concentrated solutions differed significantly from previously reported values for solutions low in cyanide concentration and that high concentrations of polysulphides tended to suppress the reaction rate.

A practical method for estimating forging loads with the use of a programmable calculator

The forging engineer must often estimate the load necessary in a press forging operation. Thus, the appropriate press capacity can be selected and, in some cases, it can be decided whether or not in-house capability exists for quoting on a given forging. This paper describes a simple load calculation method and its application to forging a steel connecting rod. The results, obtained with a hand calculator, are evaluated by comparing them with the results of computer-aided analysis and with experimental forging data. This comparison indicated that hand calculator results are sufficiently accurate for estimating forging loads and stresses. It is expected that the technique, described in this paper, will be a useful tool for the engineers in forge shop practice.

Managers and Workers: Origins of the New Factory System of the United States, 1880–1920 by Daniel Nelson (review)

Reviewed by: Managers and Workers: Origins of the Twentieth-Century Factory System in the United States, 1880–1920 * Laurence F. Gross (bio) Managers and Workers: Origins of the Twentieth-Century Factory System in the United States, 1880–1920. By Daniel Nelson. 2d ed.Madison: University of Wisconsin Press, 1996. Pp. xi+250; tables, notes, bibliography, index. $40 (cloth); $17.95 (paper). Daniel Nelson’s Managers and Workers,here in its second edition, describes the evolution of the factory setting from the late nineteenth century to the [End Page 778]early twentieth century. Nelson focuses on the role of the foreman, scientific management, labor recruitment, welfare work, and their impacts, all given final shape by World War I and Progressive governments. Only chapter 7, “The New Factory System and the Worker,” is new; the rest is lightly revised, and the notes reference additions to the scholarship since the book’s initial publication in 1975. The outlines of the tale are indeed more familiar than they were when the first edition appeared. At that time, the “new labor history,” with its shift in attention from labor organizations to activity on the factory floor, was just emerging. Nelson deserves credit as one who pioneered the new focus. His account of the gradual movement from the first generation of factories in the United States to the so-called second industrial revolution and its large, managerially controlled plants displays a broad and careful use of period sources. Managers and Workersis particularly good when considering the extent to which Taylorism derived from a variety of ongoing trends in factory management. The book also clearly describes the very limited direct impact of this “scientific management” on American industry, as opposed to the extent to which industry came to display many of Taylorism’s attributes after they had evolved further, shaped by other people and other forces. In a second edition, however, it can be valuable to consider how the book’s relationship to its historiographical context has changed. Nelson posits what might be called an invisible hand of technological change, from which emerges “better machinery” (p. 17) leading “often inadvertently [to] fundamental changes in the factory environment and in the human relationship” (p. ix). New conditions “invited” the new wisdom of factory management. Rather than emerging as part of an effort to take control of the workplace away from skilled labor, it appeared where “the legacy of the artisan shop had ceased to be an important force” (p. 10). In other words, the inexorable march of progress prevails in Nelson’s narrative. There are other problems as well, to my mind. Nelson tells a national tale but too often without reference to differences between regions and industries. He offers a chronological tale of change without considering the persistence of earlier practices, structures, and relationships. His account ranges from the specific and well referenced to the general and less substantiated. He assumes motivations and claims that most manufacturers “did not attempt to cheat or exploit their employees, at least in a financial sense.” They were “reasonable,” even “benevolent” (p. 93). Nelson omits and ignores long sections of the development of industry. He cites inside contracting and its demise as the progress of machine shop practice, omitting the previous period, when skilled workers managed production without inside contractors, whose advent they had strongly resisted. He discusses technological “improvement” in iron and steel without reference to the twelve-hour day and eighty-four-hour week it introduced. [End Page 779]He contrasts systematic management with a previous lack of coordination and ignores effective worker control of production on the floor. Nelson clearly understands how modern practice came to predominate, yet he ignores numerous works of the past twenty years that would have added depth and clarity to discussions from factory architecture, to contested changes in the workplace, to the changing attitudes of immigrant labor. He can be insightful, as when he notes that employees rather than engineers “first grasped the implications of systematic management” (p. 55). On the other hand, he ascribes the failure of the Industrial Workers of the World to confront industrialists successfully and continuously simply to their distrust of AFL-style labor-management relations (pp. 131...