Abstract: An apparatus and method for the treatment of a patient having a tumor is disclosed. An X-ray generating source is positionable at a location in close proximity to the tumor. The X-ray generating source is operable at a voltage level in the range of approximately 10-60 KeV, thereby enhancing absorption of the generated X-rays by the tumor and minimizing the side effects of radiation therapy on the patient's normal tissue.

Abstract: A method and apparatus for reducing the fatigue crack growth rate of cracks in the aluminum alloy fuselage skin of aircraft structures. A fatigue crack is identified, the crack having a tip defining the direction of crack propagation. Temperature differentials are produced between a narrow strip of the skin and portions of the skin adjacent to this narrow strip. The narrow strip extends from the crack tip to a predetermined distance forward the crack tip. The temperature differentials produced between the narrow strip and adjacent unheated portions of the aircraft skin are sufficiently high so that the expansion due to heating causes plastic flow to occur in the heated strip. The plastic flow results in a residual tensile stress which acts in the direction of crack propagation when the system is returned to a normal service temperature. This residual tensile stress is of a sufficient magnitude to effectively retard the crack growth rate.

Abstract: A secondary hardening alloy steel composition consisting essentially of about 0.25-0.5% carbon, about 0.5-1.0% manganese, about 1.5-3.0% nickel, about 0-1.0% chromium, about 1.75-2.5% molybdenum, about 0-0.4% vanadium, and an additive selected from about 1-3% aluminum and a combination of at least about 1% aluminum and at least about 1% silicon for a combined Al+Si content of about 2-4%, the balance being iron and impurity elements. The present steel composition has the following characteristics: it exhibits a flat tempering response, it is hardenable upon tempering to a Rockwell C hardness of at least 50, and it has an improved combination of hardness vs. toughness properties after tempering in the secondary hardening range. A method of preparation is also described.

Abstract: A structural steel which possess both high strength and high toughness and has particular application of cryogenic uses. The steel is produced by the utilization of thermally induced phase transformation following heating in a three-phase field in iron-rich alloys of the Fe-Ni-Ti system, with a preferred composition of 12% nickel, 0.5% titanium, the remainder being iron.

Abstract: An apparatus and method for the treatment of a patient having a tumor is disclosed. An X-ray generating source is positionable at a location in close proximity to the tumor. The X-ray generating source is operable at a voltage level in the range of approximately 10-60 KeV, thereby enhancing absorption of the generated X-rays by the tumor and minimizing the side effects of radiation therapy on the patient's normal tissue.