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List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Compounds of boron are used in organic synthesis, in the manufacture of special types of glasses, and as wood preservatives. Boron filaments are used for advanced aerospace structures owing to their high strength and light weight. It is used as an antiseptic for minor burns or cuts and is sometimes used in dressings. Boric acid was first registered in the United States in 1948 as an insecticide for control of cockroaches, termites, fire ants, fleas, silverfish, and many other insects. It acts as a stomach poison affecting the insects’ metabolism, and the dry powder is abrasive to the insects’ exoskeleton. Boric acid is generally considered to be safe for use in household kitchens to control cockroaches and ants. The important use of metallic boron is as boron fiber. Borate-containing minerals are mined and processed to produce borates for several industrial uses, i.e., glass and ceramics, soaps and detergents, fire retardants and pesticides.
Introduction
Published in Bankim Chandra Ray, Rajesh Kumar Prusty, Dinesh Kumar Rathore, Fibrous Polymeric Composites, 2018
Bankim Chandra Ray, Rajesh Kumar Prusty, Dinesh Kumar Rathore
The most evident feature of boron fibers is their extremely high tensile modulus, which is in the range of 379–414 GPa. In addition to their relatively large diameter, boron fibers offer an excellent resistance to buckling, which in turn attributes to high compressive strength for boron fiber-reinforced composites. The significant disadvantage of boron fibers is their high cost, which is even higher than that of many forms of other carbon fibers. For this reason, its application is at present restricted to a few aerospace applications.
Characteristics, Fabrication, and Design of Composites
Published in Sherif D. El Wakil, Processes and Design for Manufacturing, 2019
Boron is a very brittle material, and, therefore, a boron fiber in itself is a composite material that is made by chemical vapor deposition of boron on a fine tungsten wire. While the specific gravity of boron is 2.34, it reaches 2.6 for boron fibers due to the tungsten substrate.
Investigation of patch hybridization effect on the composite patch repair of a cracked aluminum plate: A pragmatic approach
Published in Mechanics of Advanced Materials and Structures, 2019
Alpesh H. Makwana, A. A. Shaikh, A. K. Bakare, Saikrishna Chitturi
Parts used in engineering application are not stressed uniformly, due to specific loading in certain areas. Application of a material with throughout the same strength, properties or cross-section does not require every time. Hybrid composites are developed in a logical manner to combine the superior properties of different fibers and matrix in one material. They have been developed without losing functionality to meet the various design requirement in a more economical way. Boron fiber, carbon fiber, kevlar fiber and glass fiber are used as a reinforcement constituent in the composite patch for repair of a cracked structure. Among this boron and carbon fibers are cost prohibitive compared to other materials. Carbon fibers have attractive properties like strength, stiffness, and lightweight. Carbon fiber induces galvanic corrosion of the metal due to a good conductor of electricity. Carbon fiber suffers from lack of energy absorption rate, low toughness and low strain to failure. Repairing of any high stress concentrated regions of damaged location with fiber reinforcement of low toughness provoke premature failure of a structure below design limits [3]. The composite patch prepared from carbon fiber may catastrophically fail after propagation of a crack in the patch.
Evolution of the Design and Fabrication of Astrophysics Targets for Turbulent Dynamo (TDYNO) Experiments on OMEGA
Published in Fusion Science and Technology, 2018
S. A. Muller, D. N. Kaczala, H. M. Abu-Shawareb, E. L. Alfonso, L. C. Carlson, M. Mauldin, P. Fitzsimmons, D. Lamb, P. Tzeferacos, L. Chen, G. Gregori, A. Rigby, A. Bott, T. G. White, D. Froula, J. Katz
Three generations of OMEGA TDYNO targets are shown sequentially in Fig. 1. The original design—used for first- and second-generation targets and shown in Figs. 1a and 1b—incorporated a boron fiber support structure to suspend ablator and grid components at specified critical distances. Each “rail” of this support structure consists of two boron fibers that terminate at each conical shield. Although these targets yielded valuable data,1 they were not yet optimized for achieving the desired scientific goals or for ease and precision of assembly. For example, the grids used for the first shot day did not perform as well as Flash Center for Computational Science (FLASH)aUniversity of Chicago; http://flash.uchicago.edu/site/ simulations predicted. This resulted in the testing of a new grid type during the second shot day. Another novel grid type whose design was aimed at producing a circulating flow as occurs in astrophysical accretion disks was also tested on the second day (see the Appendix).
Design and Fabrication of Opacity Targets for the National Ignition Facility
Published in Fusion Science and Technology, 2018
T. Cardenas, D. W. Schmidt, E. S. Dodd, T. S. Perry, D. Capelli, T. Quintana, J. A. Oertel, Dominic Peterson, E. Giraldez, R. F. Heeter
To place the collimator, the warm target base is leveled again and the collimator is leveled on vacuum tip with the collimator slot aligned 14 deg off horizontal before centering it in the camera view. The hohlraum, now attached to the stalk, is brought back into view and centered on the crosshairs as well. The stalk is placed so that it is at the correct height from the collimator and the stalk is glued to the collimator. The process is repeated with the capsule so that it is aligned with the top LEH and at the correct height. The capsule is glued to the glass stalk using a 100-μm-diameter boron fiber as a bridge. The fully assembled target (Fig. 16) is now ready for final metrology using an optical coordinate measurement system (OCMM).