A preliminary error budget for the third harmonic converter for the National Ignition Facility (NIF) laser driver has been developed using a root-sum-square-accumulation of error sources. Such a budget sets an upper bound on the allowable magnitude of the various effects that reduce conversion efficiency. Development efforts on crystal mounting technology and crystal quality studies are discussed.
This paper reports work done to compare the tensile creep, long-time tensile strength, and dynamic flexural fatigue-strength properties of some commercial melamine and phenolic-plastic materials. Tensile-creep data for woodflour-filled phenolic and cellulose-filled melamine indicate that these plastics exhibit similar characteristics, that is, the rate of elongation at 500 hr is essentially the same for the two materials. Likewise, the total elongation at 1000 hr is of the same order of magnitude for each of the materials. Similarly, asbestos-filled phenolic and asbestos-filled melamine show comparable tensile-creep properties. The long-time tensile strength of the cellulose-filled melamine is superior to that of the woodflour-filled phenolic material. The melamine has a long-time tensile strength of about 67 per cent of the short-time value (A.S.T.M. D638-41T), as compared with a value for the phenolic of approximately 36 per cent. Results of the repeated flexural-stress tests indicate that the woodflour-filled phenolic plastic is slightly superior to the cellulose-filled melamine, the endurance limit for the phenolic being approximately 4000 psi, or 34 per cent of the short-time static flexural strength, and for the melamine 3000 psi or 31 per cent of the short-time static flexural strength. Further tests of this nature would be desirable for the purpose of studying the effect of other fillers and formulations.
When exposed to low temperatures, organic plastics undergo changes which may be classified broadly as reversible and irreversible. Reversible effects usually include dimensional changes due to thermal contraction and loss of moisture, increased modulus of elasticity, increased yield and ultimate strengths, decreased ductility, and—most frequently, though not in every case—decreased resistance to impact. Irreversible effects may include dimensional changes due to change of state, physical failure due to lack of sufficient ductility to respond to dimensional changes, crystallization, and freezing of plasticizers or absorbed water. In either classification, extent and rapidity of every effect varies greatly, depending upon specific environmental conditions and the particular material involved. Data are presented to illustrate these various effects. Significance from a practical point of view is shown by typical examples. Also, the importance of correct design of parts is emphasized. The paucity of data at low temperatures for such properties as fatigue strength, stress endurance, and electrical constants is pointed out.
This document was prapared as an accountof work sponsod by an agency of the United States Government. Neither the United States Government nor the uNversity of Cahlkwm "a nor any of their employ-makes any wamanty, express orimpli~or assumes any legal liabilityor reaponaibilityfor the accuracy, completen~or usefulness of any informatio~appara~product, or process disclq or represents that its use would not Mringa privately ownad rights. Reference harain to any s-c commercial prod-process, orservice bylrade name, trademark, manufacturer, or otherwke, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the UNversity of California The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the UNveraity of Califcm@ and shall not be used for advertising or product endorsement t purposes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.