A neutron structure analysis of tetragonal NH4(H2PO4)
The structure of tetragonal NH4H2PO 4 has been determined in a single-crystal neutron-diffraction study. The N-If
Materials Literature
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The Role of Metal Oxides as Activators of Vulcanization
Abstract 1. The activation effect of metal oxides on the process of culvanization of nonpigmented compounds of rod polymerized sodium butadiene rubber differs from the effect in rodless polymerized rubber. In the latter case zinc oxide not only is not an activator but it retards the vulcanization process. 2. The role…
Composition of Crude Fiber in Certain Roughages
The lignin and cellulose contents of the dry matter of 11 roughages have been determined. These included two legume hays, five grass hays, oat straw, and oat silage made from plants harvested at the boot, milk, and dough stages of growth. The cellulose content of the grass hays and Korean lespedeza hay was higher than…
Melting and Glass Transitions in Polyisobutylene
Abstract The purpose of this work was to investigate the crystallization behavior of uncompounded, unstressed polyisobutylene and butyl rubber. Glass transition data obtained during the work are also reported. The data were determined dilatometrically. The work was prompted by a literature survey which collected trans…
Corrosion in Fertilizer Equipment, Corrosion of Metals by Liquid Mixed Fertilizers
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCorrosion in Fertilizer Equipment, Corrosion of Metals by Liquid Mixed FertilizersJ. D. Hatfield, A. V. Slack, G. L. Crow, and H. B. Shaffer Jr.Cite this: J. Agric. Food Chem. 1958, 6, 7, 524–531Publication Date (Print):July 1, 1958Publication History Published online1 May 2…
Glass Formation and Properties of Glasses in the System Na 2 O‐B 2 O 3 ‐SiO 2 ‐TiO 2
An investigation was made of the effect of TiO 2 on the glassforming region and on the physical properties of glasses in the system Na 2 O‐B 2 O 3 ‐SiO 2 TiO 2 . Glasses containing up to 45 mole % TiO 2 may be formed with an alkali content of 30 mole %. At lower alkali contents (10 mole % Na 2 O) glasses may be formed…
Low Energy Electron-Hydrogen Scattering
The effective range theory is developed for electron-hydrogen scattering. The scattering length as and the effective range r0s of the singlet state are determined by making use of the accurate solution of the H− ion states, as as = 7.03, r0s = 3.37 (in atomic unit). The scattering length at and the effective range r0t…
Dielectric breakdown in solids
An account is gven of the theories of intrinsic dielectric breakdown in solids, with particular emphasis on the physical process envisaged by each theory. Theories of the modified form of thermal breakdown which occurs in impulse testing are also discussed. (W.D.M.)
Thermische Untersuchungen an Sulfiden. II. Das thermische Verhalten der Sulfide des Galliums
Abstract Es wird die thermische Stabilität der Phasen im System Gallium/Schwefel bis zu Temperaturen von 1300°C untersucht. Ga 2 S 2 zerfällt vom Schmelzpunkt 970°C ab nach wobei Ga 2 S im Temperaturgebiet von 970 bis 1200° C absublimiert. Kristallines Gallium(I)‐sulfid Ga 2 S disproportioniert oberhalb 950° C in Ga 2…
Experiment on the Electron Phase Microscope
A method of electron phase microscopic observation is described which offers greater image contrasts for specimens possessing small phase differences than is possible with conventional methods of electron microscopic observation. It is shown that observation by dark contrast image using a phase plate, consisting of ma…
THE CRYSTALLIZATION OF CALCIUM SULPHATE DIHYDRATE
In this preliminary series of experiments, calcium sulphate dihydrate has been allowed to crystallize spontaneously from solutions of varying degrees of supersaturation, and induction periods and rate constants have been determined. The effect of crystal area, pH, and accelerators and retarders on this process has bee…
Über die spontane Polymerisation des Phenylisocyanids; ein neuer Weg in die Indigo‐Reihe
Abstract Bei der spontanen Polymerisation des Phenylisocyanids bei Raumtemperatur entsteht neben Harzen ein blauer Farbstoff, der isoliert und als Indigo‐dianil erkannt wurde. Substituierte und homologe aromatische Isocyanide liefern, wenn überhaupt, nur Spuren analoger Farbstoffe. Der Mechanismus dieser neuen, einfac…
The dielectric properties of solid polymers
Abstract In this paper the influence of different molecular parameters on the dielectric characteristics of amorphous high polymers has been examined. The dielectric behaviour has been compared for several polymers which carry the same dipole in the side chain, but which differ in the flexibility of the main chain (po…
THE COLD-DRAWING OF NYLON 6.6
An investigation has been made into the variation in shape of the loadelongation curve of undrawn polyhexamethylene adipamide (nylon 6.6) filaments with change in ambient conditions, isotropic refractive index of the undrawn filament and speed of extension at low speeds of extension (0.008cm/sec–0.43cm/sec). The inter…
Gray Tin Single Crystals
A method of growing gray tin single crystals from a liquid amalgam is presented together with a description of the apparatus and specification of the conditions of growth. Photographs of typical crystals ranging in size up to 2 cm and showing well-developed crystallographic planes are included. Residual resistance mea…
Nonstoichiometry in Uranium Dioxide
A thermodynamic study of the uranium-oxygen system, primarily in the single phase region UO2–UO2.20, has been made at temperatures of 1150° to 1350°K. An electrochemical technique was used to obtain emf measurements on uranium oxide half-cells. The cells were of the type Fe, FeO|(ZrO2+CaO)|UO2+x, Pt where x varied fro…
On the mechanism of the polymerization of ϵ‐caprolactam. II. The polymerization in the presence of water
Abstract Kinetic runs were performed at two temperatures with ϵ‐caprolactam–water mixtures containing from 5 to 10 mole‐% of water. The concentrations of unconverted lactam x and endgroups c were determined, and in some cases also the concentration of aminocaproic acid u 1 and the quantity of cyclic oligomers formed.…
Some Stable Hydromagnetic Equilibria
Hydromagnetic equilibria are obtained for a variety of situations which differ little from that of a zero pressure uniform axial magnetic field. Criteria for ascertaining the stability of these equilibria are found by means of an energy principle. In particular, if helically invariant fields are present, stable equili…
VOLTAIC CELLS IN FUSED SALTS: PART IV. ELECTRODE POTENTIALS OF THE SYSTEMS: Tl/TlCl (KCl–NaCl), Cu/CuCl (KCl–NaCl), Cu/CuCl2 (KCl–NaCl), Cr/CrCl2 (KCl–NaCl), AND Cr/CrCl3 (KCl–NaCl). REDOX POTENTIALS OF THE SYSTEMS: Pt/CuCl, CuCl2 (KCl–NaCl), AND Pt/CrCl2, CrCl3 (KCl–NaCl)
Using a Ag/AgCl (KCl–NaCl) reference electrode, the standard electrode potentials of the systems Tl/TlCl (KCl–NaCl), Cu/CuCl (KCl–NaCl), Cu/CuCl 2 (KCl–NaCl), Cr/CrCl 2 (KCl–NaCl), and Cr/CrCl 3 (KCl–NaCl) were measured and found to be: 0.650 volt at 680 °C, and 0.250, −0.175, 0.755, and 0.423 at 700 °C. respectively.…
CONTROL OF LINEAGE STRUCTURE IN ALUMINUM CRYSTALS GROWN FROM THE MELT
The formation of regular, continuous, straight, lowangle boundaries (striations) during freezing of a metallic crystal may be avoided by inclination of the advancing solid: liquid interface with respect to the direction of freezing. (auth)