6. Cooling of the Ocean Plates (Lithosphere) William Wilcock
William B. Johnson Associates, Inc.
1
Refrigerated CONSTANT TEMPERATURE BATH and CIRCULATING SYSTEM Larger Capacity, Lower Cost JOHNSON all purpose Constant Temperature. Bath and Circulating System features: 1. Low cost 2. Adjustable shelf 3. -29° to +72°C. range 4. 0.02°C. accuracy 5. 20 gallon capacity 6. Interiorworkingchamber: 19"L χ 16"W χ 11"D 7. Exterior: 31"L χ 22"W χ 36"H 8. Sealed compressor 9. Two pumps for internal and external circulation 10. Transistorized relay with built-in time delay 11. Stainless steel interior and top surface 12. Valved exterior circulation from second pump Model #CB-20100 $995 Request free detailed data William B. Johnson Associates, Inc. Mountain Lakes, New Jersey Circle No. 19 on Readers' Service Card Safe and Practical Nalgene Graduated Cylinders You can feel the safety and practicality of a NALGE GRADUATED CYLINDER the minute it's in your hand. Light and easy to handle, these cylinders are formed from tough, unbreakable polypropylene for greater clarity. Made in accordance with standard graduate specifications and dimensions— accurate to within 1%. Measurements are easily read since water solutions have practically no meniscus in polypropylene. Octagonal base prevents rolling. The cylinders can be autoclaved repeatedly. Cap. ml. 25 50 100 250 500 1000 Subdiv., ml. 1 2 5 10 20 25 Each 2.65 2.90 3.30 3.85 5.50 7.20 Less Quantity Discounts Ask your dealer for catalog G-358 NEWS WORLD'S LARGEST PRODUCER OF PLASTIC LABORATORY WARE Circle No. ED on Readers' Service Card Sieves have opened several new fields of analytical separation, said R. L. Mays of the Linde Co. Molecular Sieves of Type A are zeolites that con- tain Na 2 0, A1 2 0 3 , and Si0 2 in the ratio of 1:1:2, and have pore openings of about 3.2 A. (If Ca replaces Na, the openings are about 4.2 A.) The other common type, X, has these materials in a 1:1:2.5 ratio and pore openings of 8 to 9 A. Adsorption occurs as a monolayer and follows Langmuir-type curves for isothermal conditions. Mass transfer of adsorption is determined by empiri- cal methods. Heat of adsorption, how- ever, can be found by use of the Clausius-Clapeyron equation and plots of the logarithm of pressure against the reciprocal of temperature. NMR for Structure Details. As experience grows with nuclear magnetic resonance spectroscopy, the technique proves itself by providing structure de- tails much faster and more specifically than can be obtained using such meth- ods as infrared or x-ray of crystals. W. D. Phillips, Du Pont, pointed out, however, that a sample must be in solu- tion for analysis and concentrations re- quired are relatively high—in the 1-mole-per-liter range. NMR determines structure, but not geometry of materials. To get struc- ture details, Phillips described methods for observing effect of varying tem- perature to speeding up or slowing down vibration frequencies. As tem- perature is decreased, for example, new spectral peaks appear to confirm a postulated structure estimated by cal- culations and theory. Beta Particles for Analysis. Low cost, small size of equipment, steadiness of source, and a wide choice of charac- teristic x-rays make beta-excited x-ray sources attractive analytical tools, said Ralph Mûller, Los Alamos Scientific Laboratory. Thin films, such as cor- rosion films, are handled well. Such films adsorb beta particles which excite x-rays. Observation of such effects gives hope that similar analyses may be possible for organic and other mate- rials which are made up of elements with low atomic numbers. However, Miiller points out several shortcomings of present beta-excited x-ray methods. Our present knowl- edge is about equal to that of conven- tional x-rays 25 years ago. Moderate beta sources give intensities 10 4 to 10 n times smaller than conventional x-rays. And our best scintillation spectrometers are inferior to conventional x-ray spec- trometers. Tesla Luminescence Spectra. Wilson and associates at Queen's Uni- versity have built new apparatus simi- 42 A · ANALYTICAL CHEMISTRY theNALGECO. Inc. ROCHESTER 2. NEW YORK
Transcript of William B. Johnson Associates, Inc.
R e f r i g e r a t e d
CONSTANT TEMPERATURE BATH and CIRCULATING SYSTEM
Larger C a p a c i t y , L o w e r Cost J O H N S O N al l p u r p o s e C o n s t a n t Temperature. Bath and Circulating System features:
1. Low cost 2. Adjustable shelf 3. -29° to +72°C. range 4. 0.02°C. accuracy 5. 20 gallon capacity 6. Interiorworkingchamber:
19"L χ 16"W χ 11"D 7. Exterior: 31"L χ 22"W χ
36"H 8. Sealed compressor 9. Two pumps for internal
and external circulation 10. Transistorized relay with
built-in time delay 11. Stainless steel interior
and top surface 12. Valved exterior circulation
from second pump Model #CB-20100 $995
Request free detailed data W i l l i a m B. Johnson Associates, Inc.
Mountain Lakes, N e w Jersey Circle No. 19 on Readers' Service Card
Safe and Practical
Nalgene Graduated Cylinders You can feel the safety and practicality of a NALGE GRADUATED CYLINDER the minute it's in your hand. Light and easy to handle, these cylinders are formed from tough, unbreakable polypropylene for greater clarity. Made in accordance with standard graduate specifications and dimensions— accurate to within 1%. Measurements are easily read since water solutions have practically no meniscus in polypropylene. Octagonal base prevents rolling. The cylinders can be autoclaved repeatedly.
Cap. ml. 25 50 100 250 500 1000 Subdiv., ml. 1 2 5 10 20 25
Each 2.65 2.90 3.30 3.85 5.50 7.20 Less Quantity Discounts
Ask your dealer for catalog G-358
NEWS
WORLD'S LARGEST PRODUCER OF PLASTIC LABORATORY WARE Circle No. ED on Readers' Service Card
Sieves have opened several new fields of analytical separation, said R. L. Mays of the Linde Co. Molecular Sieves of Type A are zeolites that contain Na20, A1203, and Si02 in the ratio of 1:1:2, and have pore openings of about 3.2 A. (If Ca replaces Na, the openings are about 4.2 A.) The other common type, X, has these materials in a 1:1:2.5 ratio and pore openings of 8 to 9 A.
Adsorption occurs as a monolayer and follows Langmuir-type curves for isothermal conditions. Mass transfer of adsorption is determined by empirical methods. Heat of adsorption, however, can be found by use of the Clausius-Clapeyron equation and plots of the logarithm of pressure against the reciprocal of temperature.
NMR for Structure Details. As experience grows with nuclear magnetic resonance spectroscopy, the technique proves itself by providing structure details much faster and more specifically than can be obtained using such methods as infrared or x-ray of crystals. W. D. Phillips, Du Pont, pointed out, however, that a sample must be in solution for analysis and concentrations required are relatively high—in the 1-mole-per-liter range.
NMR determines structure, but not geometry of materials. To get structure details, Phillips described methods for observing effect of varying temperature to speeding up or slowing down vibration frequencies. As temperature is decreased, for example, new spectral peaks appear to confirm a postulated structure estimated by calculations and theory.
Beta Particles for Analysis. Low cost, small size of equipment, steadiness of source, and a wide choice of characteristic x-rays make beta-excited x-ray sources attractive analytical tools, said Ralph Mûller, Los Alamos Scientific Laboratory. Thin films, such as corrosion films, are handled well. Such films adsorb beta particles which excite x-rays. Observation of such effects gives hope that similar analyses may be possible for organic and other materials which are made up of elements with low atomic numbers.
However, Miiller points out several shortcomings of present beta-excited x-ray methods. Our present knowledge is about equal to that of conventional x-rays 25 years ago. Moderate beta sources give intensities 104 to 10 n
times smaller than conventional x-rays. And our best scintillation spectrometers are inferior to conventional x-ray spectrometers.
Tesla Luminescence Spectra. Wilson and associates at Queen's University have built new apparatus simi-
4 2 A · ANALYTICAL CHEMISTRY
the NALGE CO. Inc. R O C H E S T E R 2 . N E W Y O R K
