TECHNE
"TEMPUNIT f
9
LITERATURE
(Patented)
CONSTANT TEMPERATURE CONTROLLER
Push a Button, See the Formula
9935^A.°
SELF
12321
CONTAINED
- . . t h e r m o r e g u l a t o r , h e a t i n g unit, s t i r r e r , c i r c u l a t i n g p u m p in o n e unit
A self-contained unit incorporating all components required for maintaining open water baths at temperatures up to approximately 90°C, and for circulating water to external apparatus a t a rate of 1 M quarts per minute at 1 ]/2 ft. head. The unique indicating thermoregula t o r system, with pneumatically actuated switch for control of heater, has the sensitivity of electrical contact methods b u t with greater dependability and longer life. Can be preset to any desired temper ature 0 to approx. 90°C. Maintains tem perature constant within ±0.05°C in a 4-gallon cylindrical glass vessel, 12 X 12 inches, without insulation. With built-on clamp for attachment t o vessels with wall thickness up to 114 inches. The helical, bimetallic sensing element, stirrer, aspirator tube and IQOO-'watt tubular immersion heater are integrally attached beneath the housing. Stirring motor, 1/20 h.p., is fan cooled, induction type, witl* self-lubricating bear ings, suitable for continuous use. Overall dimensions 6% inches wide X 7 inches deep X 1 1 H inches high. Tubulation for connection of pump to external apparatus is ^g-inch outside diameter. 9935. Constant Temperature Bath Controller, Techne "Tempunit" (Patented), as above described, complete with 4-ft., 3-wire connecting cord with 2-prong, parallel blade attachment plug cap, and directions for use. Power consumption 1 0 4 0 watts. For use on Π 5 volts, 5 0 or 6 0 cycles, a.c. Without bath 135.00 9935-A. Ditto, complete with bath consisting of cylindrical jar of Pyrex brand glass, 1 6 inches diameter X 1 2 inches high, capacity 8 16 gallons 178.59
ARTHUR H. THOMAS CO. Laboratory Apparatus and Reagents VINE ST. AT THIRD
PHILADELPHIA 5, P A . Afore and more laboratories RELY GN THOMAS
108
C&EN
APRIL
2 8,
1958
Norma B a i r d a n d Ascher Opler
Chemical Structures by Computer D o w Chemists find w a y t o c o n v e r t f o r m u l a s to struc t u r e s , d e p i c t t h e m o n oscillo scope Anyone who 4 Λ Λ ACS ' ^ a - ^ a d to wprk 1 1 ^ NATIONAL ™th l o n S ' ^sts of I VVMEETING new or complex compounds will Chemical' w el c ο m e t h e Literatvre latest advance in computer applica tions by Àscher Opler a n d Norma Baird of Dow Chemical. I n s t e a d of trying to visualize structures mentally from formulas, or even to write t h e m out, he can s e e them displayed pictorially on an oscilloscope or examine the structures a t leisure on film. The n e w technique will b e especially useful in examining lists of compounds turned u p in literature or patent searches, Norma Baird told die Division of Chemical Literature. Actually, the c o m p u t e r displays structures too
fast for visual inspection; the usual procedure is t o film t h e m as projected and to make prints or filmstrips. In approaching their task, Opler and Baird m a d e u s e of the fact t h a t all chemical structures are m a d e u p of repeating p a t t e r n s of letters, numbers, and simple geometrical designs. T h e first problem w a s t o find a w a y of depicting these units on the computer oscilloscope. This they solved b y using a 64-dot square t o depict t h e basic units, including simple combinations of lines. The selected dots are thrown on t h e screen in succession b u t so quickly that the design appears instantaneously. P u n c h e d card codes consisting of two-letter or number combinations were worked out to yield any desired symbol on d e m a n d in the 64dot s q u a r e . T h e y found that a matrix 32-squares each w a y is enough to display any chemical formula. So they divided the oscilloscope screen into 1024 areas, each containing a 64-dot square. This meant t h a t in addition to the code for the symbol, codes for the coordinates would b e needed to place the square depicting the symbol on t h e screen. This takes two more two-number combinations, zero to 3 1 . To display the
n u m b e r 7 in the upper right-hand corner, the code is 313107; to p u t H i n t h e center of t h e screen, t h e code is 15150H, for example. For larger symbols, such as a benzene ring, more than o n e square is needed, each with i t s six-digit code. T o avoid cumbersome and repetitious codes, however, Opler and Baird have worked out 2-digit codes for a n u m b e r of radicals or groups that occur frequently. Thus a horizontal b e n z e n e ring is coded by PH; a vertical b e n z e n e ring by PV. Similarly, a right-handed nitro group ( N 0 2 ) is coded a s RN; a left-handed nitro group (ON 2 ) as L N . While t h e technique they developed is based on IBM equipment, Opler a n d Baird point out that i t can be a d a p t e d to other systems. T o carry it out i n volves these steps: • Each unit of structure is coded with six numbers, which are p u n c h e d into IBM cards. "· T h e cards are fed into a m a c h i n e t h a t "writes" t h e code directly onto a magnetic tape. Codes for up t o 100,000 compounds can b e stored on o n e tape. • T h e t a p e is fed into the I B M 7 0 4 with a program of instructions t h a t p r o d u c e a dot-by-dot display of t h e structure. This is shown on a combination oscilloscope and camera. • Individual o r strip prints a r e m a d e from the film for visual inspection at leisure. While t h e system can yield a l l structures in a list, perhaps a more useful purpose is to combine t h e technique with other programs such as searching, indexing, correlating, and sorting. Thus, any computer program for handling chemical information m a y b e coupled to this technique to print out pictorially. The present system is geared t o simulate type-set structures. I t could b e adapted, says Opler, to displaying electron densities, bond configurations, or any other form of information susceptible t o graphic depiction. In studying reactions, for instancy, t h e machine could b e programed to compute a n d display densities of electron fields around the reactants as they approach each other. Information of this type, presently available a s tables of figures from computers, can b e much more meaningful through pictorial presentation. Other areas of possible use might b e steric effects, ionization, and x-ray diffraction.
GROCOL 600 by all t e s t s , t h e best Hydrogenated Tallow Glyceride Strict quality control in the manufacture of G R O C O L 600 Hydrogenated Tallow Glyceride has established a new benchmark for t h e industry—an iodine value of below O.5. This indicates extremely low unsaturates and assures correspondingly long shelf life for your products—whether quality plasticizers, esters, lubricants or finishing agents for leather or textiles. Lightness of color is unexcelled. Stability under heat is outstanding. In a recent test, production samples of GROCOL 600 gave a Lovibond reading of 0.2 red a n d 1.3 yellow before a n A.G.C.S. method heat test, and a reading of 0.2 red and 2.2 yellow afterward. .; ,. - ;. , · Free fatty acid content is well under 0.5% with an average below 0.25%. Unsaponifiables are 0.25% maximum. Odor is bland. Your payoff in sales will improve if you "Always specify A. Gross" Hydrogenated Tallow Glyceride—GROCOL 600. You can see why. Send for samples and brochure*, "Fatty Acids in Modern
Industry."
FATTY ACIDS Stearic A d d s · Red Oils· White Oléines Tallow Fatty Acids · Coconut Fatty Acids · Vegetable Fatty Acids Hydrogenated Fatty Acids · Hydrogenated Tallow Glycerides
a. gross
295 Madison Ave., N. Y. 17, N. Y.
·
Distributors in principal
Manufacturers since 1837
cities
APRIL
·
2 8,
factory: Newark, N. J.
1958C&EN
109
