Guayule seedling response to nitrogen fertilizers

Slow growth and high seedling mortality limit direct seeding establishment of guayule (Parthenium argentatum G.). This study was conducted to assess seedling growth enhancement by the addition of different rates and forms of N fertilizers and Ca salts. Experiments were conducted in a greenhouse with cultivar 593 under both surface and subirrigated conditions using water low in salts (salinity of 0.8 dSm^–1, SAR of 5.0 and 10 mg Ca L^–1). Under surface-irrigated conditions, seedling height and fresh plant weight increased with N application to the irrigation water to 70 mg L^–1. The best seedling growth was observed when (NH₄)₂SO₄ was added in combination with CaCl₂ or CaSO₄. Progressively less growth was observed by addition of (NH₄)₂SO₄ alone, CO(NH₂)₂ plus CaSO₄, CO(NH₂)₂ alone and Ca(NO₃)₂. When seedlings were subirrigated, however, the best growth was observed with Ca(NO₃)₂. Intermediate growth was obtained with (NH₄)₂SO₄ plus CaSO₄ and lowest growth rates with (NH₄)₂SO₄ alone. These differential responses may be explained by the differences in leaching and volatile characteristics of the N forms. Growth enhancement from N and Ca additions increased with time with significant increases 45 days after seeding. Nitrogen application with Ca may be effective amendment in promoting subsequent growth of direct seeded guayule.     

Channel-collapse effect examined with laboratory equipment and by two-dimensional calculation

Combustion, Explosion, and Shock Waves -     

Structure formation in production of yttrium-silicate materials by the sol-gel method

Materials made from yttrium silicates were synthesized by the sol-gel method. The effect of the amount of yttrium oxide, which varied from 10 to 50% (molar content), and the water:alcoholate molar ratio was investigated. Structure formation and the character of crystallization of gels in heat treatment in the 650–1300°C range were investigated. __________ Translated from Steklo i Keramika, No. 1, pp. 3–6, January, 2007.     

Mechanical relaxations in polybutene-1 and poly-4-methylpentene-1

Dynamic mechanical measurements between — 180°C and 180°C were made on both isotropic and drawn samples of polybutene-1 (PB-1) and poly-4-methylpentene-1 (P4MB1) over a wide frequency range by the use of a torsional pendulum (0.3–3 Hz), a viscoelastic spectrometer (5–90 Hz) and ultrasonic technique (3 MHz). The relaxation peaks were identified and the associated activation energies determined from Arrhenius plots. For PB-1 it was observed that orientation reduces the height and shifts up the temperature of the α_a-peak associated with large scale main-chain motion in the amorphous regions, but has little effect on the β-peak associated with side-group motion. In addition to the α_a and β relaxations a high-temperature crystalline relaxation (α_c) is also observed in P4MP1. For both the α_c and β relaxations the mechanical loss at 45° to the draw direction is much larger than that at 90°, which indicates that shear processes are involved in these relaxations.     

Perfecting operation of an apparatus for two-stage deasphalting of residuum with liquid propane at the Ryazan' refinery

Chemistry and Technology of Fuels and Oils -     

A Digital Recording System for Body Temperature Telemetry from Small Animals

A relatively simple instrumentation system is described which samples and records the body temperatures from up to twelve experimental animals over long periods of time. Body temperatures are sensed by temperature-sensitive FM transmitters implanted in the peritoneal cavities. The emitted signals are received by antennas, amplified, and sequentially gated into a frequency counter for counting; the resulting digital numbers are recorded in binarycoded decimal (BCD) format on punched paper tape. Samples can be spaced at intervals of from 1 to 60 minutes, and sampling can be continued over long periods of many months. This system eliminates the need for analog-to-digital conversion and allows rapid and direct transmission of the raw data to the digital computer for processing and analysis.     

Skin and layer formation in films prepared from carbohydrates,poly(ethylene-co-acrylic acid), and polyethylene

Cornstarch, a canary dextrin, and a maltodextrin were compared in films blown from carbohydrates compounded with poly(ethylene-co-acrylic acid) (EAA), low-density polyethylene (LDPE), and aqueous ammonium hydroxide plasticizer. Dextrins or maltodextrins having dextrose equivalent values of one and greater caused dark-colored films with caramel odors, probably due to Maillard reactions. Blown films with hydrophobic skins and water sensitive cores were produced with the dextrinized carbohydrates, but not from natural cornstarch. Water sensitivity of films containing the dextrinized carbohydrate was reduced by recycling the films through the blown film die. A mechanism for development of the skins is proposed, as is a method for preparing thin semipermeable membranes. © 1993 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.