Silicone modified resins for graphite fiber laminates

Six silicone modified resins were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 6-63%. The highest flexural values measured for the laminates were a strength of 1,220 MPa and a modulus of 105 GPa. The highest interlaminar shear strength was 72 MPa

Silicone modified resins for graphite fiber laminates

The development of silicon modified resins for graphite fiber laminates which will prevent the dispersal of graphite fibers when the composites are burned is discussed. Eighty-five silicone modified resins were synthesized and evaluated including unsaturated polyesters, thermosetting methacrylates, epoxies, polyimides, and phenolics. Neat resins were judged in terms of Si content, homogeneity, hardness, Char formation, and thermal stability. Char formation was estimated by thermogravimetry to 1,000 C in air and in N2. Thermal stability was evaluated by isothermal weight loss measurements for 200 hrs in air at three temperatures. Four silicone modified epoxies were selected for evaluation in unidirectional filament wound graphite laminates. Neat samples of these resins had 1,000 C char residues of 25 to 50%. The highest flexural values measured for the laminates were a strength of 140 kpsi and a modulus of 10 Mpsi. The highest interlaminar shear strength was 5.3 kpsi

Synthesis of pyrrone polymers, 21 June 1967 - 21 June 1968

Synthesis of pyrrone polymers by reactions of dianhydride and diacetoamido diamines or with tetramin

Early-type Galaxies in the Cluster Abell 2390 at z=0.23

To examine the evolution of the early-type galaxy population in the rich cluster Abell 2390 at z=0.23 we have gained spectroscopic data of 51 elliptical and lenticular galaxies with MOSCA at the 3.5 m telescope on Calar Alto Observatory. This investigation spans both a broad range in luminosity (-19.3>M_B>-22.3) and uses a wide field of view of 10'x10', therefore the environmental dependence of different formation scenarios can be analysed in detail as a function of radius from the cluster centre. Here we present results on the surface brightness modelling of galaxies where morphological and structural information is available in the F814W filter aboard the Hubble Space Telescope (HST) and investigate for this subsample the evolution of the Fundamental Plane.Comment: 5 pages, 5 figures, to appear in "Carnegie Observatories Astrophysics Series, Vol. 3: Clusters of Galaxies: Probes of Cosmological Structure and Galaxy Evolution", ed. J. S. Mulchaey, A. Dressler, and A. Oemler (Pasadena: Carnegie Observatories, http://www.ociw.edu/ociw/symposia/series/symposium3/proceedings.html

A study of the moisture in butter.

The adoption of any standard of purity of butter requires a knowledge of the effects of the different constituents of butter upon its quality. This knowledge, in so far as the effect of different percentages of water is concerned, has been, up to the present time, somewhat meager. In fixing the moisture standard considerable controversy has arisen as to whether or not 16 per cent is the most desirable amount. The evidence available goes to show that so far as quality is concerned, butter containing from 141/2 to 16 per cent water is not inferior to that containing a lower percentage. Butter is not bought on a basis of its actual food value. This is confirmed by the high prices consumers are willing to pay for this article in comparison with prices paid for other equally nutritious food products. The marked differences in value of butter of different grades would indicate that butter is bought primarily as a relish. Its food value should not, however, be overlooked in a consideration of this question

Method of determining the moisture content of butter.

The commercial value to those engaged in creamery management of knowing the moisture content of butter has created a want for some simple and accurate means of ascertaining the percentage of water in butter. The recent stringent enforcement of the pure food law has emphasized its need in the case of dealers. To meet the demand several methods have been devised and placed upon the market. In the use of these, reliability of results has been questioned, and it has been felt that official tests should be made to determine their accuracy. This bulletin gives a description, of the methods commonly used, with comments upon them. Their results are compared with the standard gravimetric analysis recognized by the Association of Official Agricultural Chemists. In making comments, the writers have taken into consideration conditions as they exist throughout the creameries. Simplicity of method, cost of apparatus, expense of manipulation and the intelligence of the labor employed, are also dealt with. Variations in the water content, so far as they affect the results of the methods, are given general consideration

Bimodal AGNs in Bimodal Galaxies

By their star content, the galaxies split out into a red and a blue population; their color index peaked around u-r=2.5 or u-r=1, respectively, quantifies the ratio of the blue stars newly formed from cold galactic gas, to the redder ones left over by past generations. On the other hand, upon accreting substantial gas amounts the central massive black holes energize active galactic nuclei (AGNs); here we investigate whether these show a similar, and possibly related, bimodal partition as for current accretion activity relative to the past. To this aim we use an updated semianalytic model; based on Monte Carlo simulations, this follows with a large statistics the galaxy assemblage, the star generations and the black hole accretions in the cosmological framework over the redshift span from z=10 to z=0. We test our simulations for yielding in close detail the observed split of galaxies into a red, early and a blue, late population. We find that the black hole accretion activities likewise give rise to two source populations: early, bright quasars and later, dimmer AGNs. We predict for their Eddington parameter $\lambda_E$ -- the ratio of the current to the past black hole accretions -- a bimodal distribution; the two branches sit now under $\lambda_E \approx 0.01$ (mainly contributed by low-luminosity AGNs) and around $\lambda_E \approx 0.3-1$. These not only mark out the two populations of AGNs, but also will turn out to correlate strongly with the red or blue color of their host galaxies.Comment: 7 pages, accepted for publication in the Astrophysical Journa