Instruments for measurement and control

BOLTZMANN'S DISTRIBUTION LAW. E. A. Guggenheim, Professor of ... Fermi-Dirac and Bose-Einstein Distributions. All of this material is presented and ...
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JOURNAL O F CHEMICAL EDUCATION

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BOLRMANN'S DISTRIBUTION

LAW

E. A. Guggenheim, Professor of Chemistry, University of Reading. Interscience Publishers, Inc., New Yark, 1955. 61 pp. 4 figs. 12.5 X 18.5 cm. $1.50. THEcontents of thirr book can best be described by listing the chapter headings. These are: Elements of Quantum Theory; Temperature and Partition Functions; Sepssable, Unexcited and Classical Degrees of Freedom; Harmonic Oscillator; Ideal Monatomic Gas; Free Energy and Total Energy; Equilibrium; Equipartition of Kinetic Energy; Simple Crystal; Ideal Diatomic Gas; Dielectric Constant of a Gas; Chemical Equilibrium; Fermi-Dirac and Bose-Einstein Distributions. All of this material is presented and discussed within 61 small pages. This is unusual in that most authors would use ten times as much space in writing a book over the same material. As a result of this, all of the equations can not be adequately derived or explained in any detail. However, considering that the author wished to maintain s. maximum brevity, he has succeeded very well. The book is well written and can be highly recommended to graduate students in chemistry. Chapter 10 which deals with phase equilibrium seems to me to be out of place. However, perhaps the author wished to show how to develop the Clapeyran equation without using the concept of entropy. As far as the reviewer was able to ascertain, the word "entropy" was never used in thirr book. This is unfortunate since it is also a very interesting and useful function. J. R. LACHER

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The last third of the book, which deals with stationary states in flow processes, is happily free from polemic. The transition from energetics is a little easier than from Gibbsian thermodynamics because of the previous stress on processes, and is made a little too easy by omitting discussion of the assumptions that the potentials exist in systems not in equilibrium. This treatment also suffers in comparison with other recent ones in not using the Onsager reciprocal relations. In the foreword, La Mer elsims a didactic advantage in introducing reversible processes before irreversible processes. There is rertaiinly a didactic loss in denying much that the student has already learned. The balance depends greatly upon the enthusiasm of the teacher, and also upon the backgrounds of the class. Students u.ho have grown up since the &st atom bomb are not strangers to energy. It seems to me that the pprchologiral "entropy barrier" is less formidable than it used to be. The Gibbs-Lewis method may be likened to a, quantum tunneling from where the students hit the barrier to the region of functions of state, where they learn by doing. Brensted seems to insist that they go back to the origin, throw away any helps from atomic or quantum theory, and climb by new and rugged paths over the highest peak of rationalism. A briefer comparison might he with the Berlite and the grammatical approaches to language study.

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INSTRUMENTS FOR MEASUREMENT AND CONTROL

Werner G. Holzbock, Development Engineer, Askria Regulator Company. Reinhold Publishing Cop., New York, 1955. vi + 371 pp. 217 figs. 15.5 X 23 om. $10.

PRINCIPLES AND PROBLEMS IN ENERGETICS

I. N. BS3nsted, Late Professor of Physical Chemistry, University of Copenhagen. Translated by R. P. Bell, Balliol College, Odord University. Interscience Publishers, Inc., New York, 119 pp. Figs. 15.5 X 23.5 em. $3.50. 1955. vii

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I ANTICIPATED with great pleasure studying this book for review bemuse I expected to understand Brensted's ideas on energetics from his own words. I am disappointed because I think I do not understand them after careful study. If I do understand, I am still disappointed. The book consists of three approximately equal parts. Some of my difficulty is that the first third, which is an attack on "elsssieal thermodynamics" as irrational, is mixed with the second third, which is a presentation of Br8nstedian energetics. Most Amerioan chemists associate "classical thermodvnamies" with i s ,w i or I . Their rhvrmwlynnrnic~ HIP alm031 twrm.I! with iwrtiur..i of tlw *r.trr of a 3ytitcm xnd uws proresscs, ltcat :tnd n o r k iwstly in sirnplr vnsrr, to mansun. funvrions such as energy and entropy. The attack is not upon them, but is upon the classical physical concepts of beat and work and upon the ideas of CarathEadory and Born. To rationalize this subject Bronsted invents new vssiables, which he calls work and heat. They are not functions of the state of the system and me not made to appear more necessary or useful to Gibhsim thermodynamics than the variables which are classically given these names. He places great emphasis on processes. Another of my difficultiescomes from the use of work, heat, and several other terms in a special BrBnstedian sense. I understand however that the functions of the state of a, system have their customary definitions. Energy does not appear except casually until Chapter BI. If Brenstedian energy is discussed a t all it is in the second paragraph. The last half of this paragraph says that energy elements which do not represent work or heat do not obey the relations necessary for the very existence of the energy concept, but are included in the class of true energy elements for formal reasons. I can find no clue as to what are the elements, the relations, or the formal reasons. ~

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HERE is a nonmathematical description of various types of instruments commonly used for measurement, recording, or control of process variables a t remote locations. The variables discusaed are temperature, humidity and moisture, pressure, flow, liquid level, density, viscosity, speed, and analysis by various methods. The mechanics of various types of controllers are discussed, as automatic controller action; electric controllers; self-operated, pneumatic, and hydraulic controllers; time function controllers; and final control elements. A brief final chapter discusses trends in instrumentation and looks into the future on automation. A glossary defines terms commonly used in instrumentation. Probably the outstanding feature of the book is the wealth of schematic diagrams of the mechanisms of various classes of instruments. There sre a few pictures of the instruments themselves that tell nothing, but the diagrammatic and hook-up sketches show much. The author has presented adequately a description of the method of operation and the type of control that can be achieved with the instrument. K E N N E T H A. Uxwenswr .*u~T,N,

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KOBE

T e x ~ TEXAS OF

CLINICAL BIOCHEMISTRY

Abraham Cantarow, Professor of Biochemistry, Jefferson Medical College, and Max Trumper, formerly Lecturer in Clinical Biochemisky and Basic Science Coordinator, Naval Medical School, National Naval Medical Center, Bethesda, Maryland. Fifth edition. W. B. Saunders Co., Philadelphia, 1955. nnd 738 pp. 54 figs. 44 tables. 16 X 24 cm. $9.

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SINCEthis book, now in its H t b edition, first appeared in 1932 it has become well established as an important helper to the practicing physieisn as well as the clinical chemist who wishes to correlate biochemical data, with diagnostic and prognostic problems in medicine.