I
BOOK REVIEWS ects for laboratory courses in inorganic chemistry. The technique is essentiall? simple and requires little unconventional apparatus, and much work remains to he done in the exciting field of preparing elements in the pure condition and investigating their properties.
LAURENCES. FOSTER Ordnance Materials Research Office Ti'ale~town,Massachusells Recent Advancer In Heat and Mass Transfer
Edited by J . P . Harlnelt and E. R. G. Eekert, both of the University of Minnesota, Minneapolis, H. S . Mickley, Massachusetts Institute of Technology, Csmhridge, and K. L. Pigford, University of Delaware, Newark. M e Graw-Hill Book Co., Inc., New York, 1961. viii 404 pp. Figs. and tables. 16.5 X 24 cm. $9.i5.
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"Recent Advances in Heat and Mass Transfer" was compiled to bring together under one cover a collertion of papers useful to practicing engineers and rosearchers. These papers --ere selected irom the technical literature and presumably represent t,he most significant contributions to the theory and practice of heat and mass transfer. Sixteen papem are included. About half of the work deals with some form of boundary layer theory as applied to problems of heat snd mass transfer with some consideration given to chemical reaction. I t is in the area, of boundary layer theory that the hook finds its strength. Also the turhulent transport mechanism in circular tubes is reasonably well covered with the inclusion of several excellent papers on this important and difficult subject. The coverage of other subject material is incomplete and certainly researchers inter~stedin aspects of heat and mass transfer other than the two mentioned above will find the collection incomplete and of little value. The sixteen articles all appear in readily accessible journals and with an exception, all were originally written in English. Thus with t,he advent of modern copying machines and the availability of reprint,^, it will he difficult to justify purchasing this book even though a numher of the articles selected are classics in their area.
R. S. SCHECHTER b'niversily of Tezas Austin Synthesis of Optimum Control Systems
Sheldon S. L. Chang, New York University, Xew Yark. McGraw-Hill Book Co., h e . , New York, 1961. xii 381 pp. Figs. and tables. 16 X 23.5 em. $11.75.
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Professor Chang's book deserves to be read by everyone seriously interested in automat~ccontrol, for it describes the most recent developments in the theory of optimal control. Many of these advances are the work oi the author him-
self, which makes most of the book quite original. This originality makes it appear, a t first glance, completely beyond the grasp of most chemical engineers. On reading the work, however, one soon finds thzt although the problems studied are rather advanced, the methods are not so esoteric after all. They are in fact straightforward and elegant extensions of such standard techniques as the root locus method. This is not to imply that the hook is easy to rend. Before tackling it, one should have his elementary control theory well in hand. including an understanding of sampled-data syst&s. Contour ;i tegration in the complex plane is used extensively, and although there is an appendix on basic statistical theory, the ohapters concerning random inputs would he difficult for anyone not having studied probability theory already. For the adequately prepared reader, however, the offort expended in studying this work would he rrell rewarded. Although the book's voeahulary has an dectramechanie d flavor, the terminology should he understandable to anyone versed in basic control theory. The hook would he a good text for R. chemical engineering graduate course on optimiaation in automatic rontrol. Two measures of control syst,em eRectiveness are used throughout: the integrated squnrcd error and the settling time. Control systems which minimize one or tho other of these criteria are developed for random as well as deterministic input,^, and for sampled-data as well as rontinuous systems. Most
of the hook concerns linear systems, but minimal time control of non-linear systems is also discussed. The two chapters on seli-optimizing and adaptive systems should be of considerable interest to chemical engineers, as should the comparison, sketchy as it is, of Bcllman's Principle of Optimality (Dynamic Programming) with Pontryagin's Milximum Principle in the find chapter on compukr optimiaation of non-linear systems. There is a great deal of cohesion and unity in the text; principles developed in early chapters often reappear in later ones under different circumstances. Laplace transform methods developed for continuous systems set the stage lor the optimization of sampled data systems hy the z-transform techniques several chapters later. Perhaps the most striking integration of concepts is the use of sampled-data theory in the optimization of an adaptive controlsystem. I t is important from a pract,ical standpoint that Professor Chang's analysis has taken account of side conditions surh as power limitations which limit thc range of fluctuation of the variables. He has also concerned himself with two auxiliary topics of practical interest. One chapter is devoted to the estimation and measure ment of the properties of random signals, specifically their power spectra and correlation functions. Another analyzes thc sensitivity of systems to onmponent inaccuracies. Specid note should be taken of the author's elegant root square locus met,hod (Conlinved on page A500)
BOOK REVIEWS
Technical Report Writing
Fred H . Rhodes, Cornell University, for optimizing control systems. It works not only for deterministic systems, but also for those with stationary random inputs. Non-st,ationary systems, being much more difficult to analyze, are treated by less satisfying methods in a separate ohapter., Without hesitat,ion we can endorse this book as a real advance in oontrol theory that should have as lasting an influence as is possihle in such a rapidly developing field of technology. I t s examples and illustrations complement the text nicely, and there are prohlems in the hack suitable for graduate level instruction. D o u c ~ ~J.s sWILDE University of Tezas
Austin
Ithaca, New York, McGraw-Hill Book Co., Inc., New York, 1961. 2nd ed. vii 168 pp. 14.5 X 22 om. $5.50.
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Writing a Technical Paper
Donald H . M e n d and H o w a d Mumford Jones, both of Hanrard University, and Lyle G. Boyd, Smithsonian Astrophysical Observatory, Washington, D. C. McGraw-Hill Book Co., Inc., New York, 1961. ix 132 pp. 14 X 21 cm. 83.25.
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Forty-seven hooks are in print in English on technical writing and reporting, one of my eolleltgues informed me several weeks ago. These two make 49-though by this time, the number is likely t o be 59. I t is a credit to the authors and the pub-
lishera t h a t these two are worth-while additions. I wish that being "modern" did not force these brief, meaningless titles. The 16th, 17th, 18th century had no qualms about long tit,les which truly reflected tho contents. Thus, "Writing A Technical Papcr," by Meneel, Jones, and Boyd would have been graced with a title something like "A Lighthearted, Well-Writben, Conscientious Little Book Directed toward Making Even Technical People Conscious of T h a t i t Means T o Be Literate and To Enable Them Suhsequently t o Impart Some of the Literary Quality t o Their Canbributions to the Technical Literature." I n their seven chapters the authors have made lively reading of the sections entitled: The Evolution of aPaper, Revision, Presenting the Data, Grammar, Style, Jargon, The Physierl Manuscript. For instance, in discussing how the author ran best get his material down on paper, they discuss the "trance method," the "relaxed method," the "method of total recall," and the "brute force method." Common hazards of phrasing and grammar discussed include not only the expected cliche8 and danglers, hut squinters, minor irritants, near-hits, and juvenile forms. The examples of "srienrh" xviil make even the m o ~ tn011-word-conscious technical man chuckle, ~ h i l ea t the ssme time needling him to he more careful of his diction, t o be aware of what his r o r d s say t o his reader not merely what he bhinks they say. Bravely the authors opt far the split infinitive when not t o split it fails to impart theexaet meaning. The long chapter on st,yie comes closest to giving the technical man a feel for this elusive aspect of writing of anything I have read. It. convinces the reader that technical papers and reports can he good reading-if the writers are literate. A fuller title of Rhodes "Technical Report Writing" might have been: "Analysis and Presentation of Data for and in a Report in Which i t is Wished t o Squeeze Out of Every Possible Datum the Quantitative Essence," because not until Chapter 8, The Graphical Presentation of Data, does Rhodes' book come alive. The first seven chapters such as The Characteristics of a Good Report and The Style of a, Report present the crochets of r. retired professor of chemical engineering who, over several decades, has corrected thousands of undergraduate laboratory reports in chemical engineering. But he writes with enthusiasm and firm lucidity of Arithmetical Graphs, Integration Graphs, Logarit,hmical Graphs, Graphics on Triangular Grids, Histogrsms, Cumulative Frequency Graphs. Succinctly he tells the reader how to arrive a t the data which are t o be presented in these graphs in sections entilted Method of Dispersion, Distribution of Sample Means, Combining Probabilities, Correlation Analysis, and Calculation of Correlation Coefficient. Briefly he tells the harassed writer not only how easily ta use these tools but how not t o use them. Within the last week I have
(Continued n page A501)
A500
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Journal of Chemical Education.
