Investigation of the flaw growth characteristics of 6Al-4V titanium used in the Apollo spacecraft pressure vessels

Failure analysis of flaw growth characteristics of 6Al-4V titanium forgings used in Apollo spacecraft propellant tank

Cyclic and sustained load flaw growth characteristics of 6Al-4V titanium Final report

Cyclic and sustained load flaw growth properties of titanium alloys for pressure vessel

Fracture characteristics of structural aerospace alloys containing deep surface flaws

Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions

Deep flaws in weldments of aluminum and titanium

Surface flawed specimens of 2219-T87 and 6Al-4V STA titanium weldments were tested to determine static failure modes, failure strength, and fatigue flaw growth characteristics. Thicknesses selected for this study were purposely set at values where, for most test conditions, abrupt instability of the flaw at fracture would not be expected. Static tests for the aluminum weldments were performed at room, LN2 and LH2 temperatures. Titanium static tests for tests were performed at room and LH2 temperatures. Results of the static tests were used to plot curves relating initial flaw size to leakage- or failure-stresses (i.e. "failure" locus curves). Cyclic tests, for both materials, were then performed at room temperature, using initial flaws only slightly below the previously established failure locus for typical proof stress levels. Cyclic testing was performed on pairs of specimens, one with and one without a simulated proof test cycle. Comparisons were made then to determine the value and effect of proof testing as affected by the various variables of proof and operating stress, flaw shape, material thickness, and alloy

Investigation of crack growth threshold of Inconel 718 exposed to high pressure oxygen Final report 24 Apr. - 25 May 1970

Crack growth threshold investigation of Inconel 718 exposed to high pressure oxyge

Investigation of deep flaws in thin walled tanks

Growth of deep surface flaws in thin wall tanks of aluminum and titanium base metal

What is \u27equity\u27 in education

Equity in education is often viewed as equivalence or sameness. A more useful way to view equity is through the lens of ‘fairness’

Suprathermal electrons at Saturn's bow shock

The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach number) than these SNR shocks. However, the Cassini spacecraft has shown that the shock standing in the solar wind sunward of Saturn (Saturn's bow shock) can occasionally reach this high-Mach number astrophysical regime. In this regime Cassini has provided the first in situ evidence for electron acceleration under quasi-parallel upstream magnetic conditions. Here we present the full picture of suprathermal electrons at Saturn's bow shock revealed by Cassini. The downstream thermal electron distribution is resolved in all data taken by the low-energy electron detector (CAPS-ELS, <28 keV) during shock crossings, but the higher energy channels were at (or close to) background. The high-energy electron detector (MIMI-LEMMS, >18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (<100 keV) were above background. We show that these results are consistent with theory in which the "injection" of thermal electrons into an acceleration process involves interaction with whistler waves at the shock front, and becomes possible for all upstream magnetic field orientations at high Mach numbers like those of the strong shocks around young SNRs. A future dedicated study will analyze the rare crossings with evidence for relativistic electrons (up to ~1 MeV).Comment: 22 pages, 5 figures. Accepted for publication in Ap

Defining end user requirements for a field-based molecular detection system for wildlife forensic investigations

The increasing use of non-laboratory-based DNA and protein detection methods promise to provide rapid investigative intelligence and support sample prioritisation. Primarily developed for human forensic or medical applications, current systems may also show utility in the field of wildlife forensic science. However, it is currently unknown whether the requirements of the wildlife forensic community can be met by current non-laboratory based tools. Given the diverse array of stakeholders and sample types commonly encountered, it is necessary to first identify the needs of the community and then try and map their needs to current instrumentation. By using a market research style questionnaire, this study identified key requirements for a non-laboratory-based system following feedback from the wildlife forensic community. Data showed that there is strong support for field-based detection methods while highlighting concerns including contamination risks and reduced quality assurance associated with non-laboratory testing. Key species and applications were identified alongside hurdles to implementation and adoption. Broadly, the requirements align with many of the developmental drivers that have led to the rise of in-field portable detection instrumentation, specifically rapid detection within one hour, ease-of-use, and ≥95% accuracy. Several existing platforms exist that met some of the identified requirements but not all. With further collaboration between industry partners and the wildlife forensic community it is possible that new field-based systems can be developed and applied routinely

Equine atypical myopathy associated with sycamore seed ingestion in a Przewalski foal

One of the 172 UK cases of equine atypical myopathy (EAM) reported to the Atypical Myopathy Alert Group (AMAG) in 2014 was that of a five-month old male Przewalski horse (Equus ferus przewalskii), resident at ZSL Whipsnade Zoo, UK. The foal presented initially with sudden-onset and repeated stretching of the neck as if dysphagic, with progressive weakness (including lying down), sweating and an unresponsive demeanour. General anaesthesia, induced with a combination of etorphine, midazolam and hyaluronidase, was required for each examination and subsequent treatment of the foal. Initial biochemical analysis showed a markedly increased plasma creatine kinase (CK) activity of 105,001 U/L, an increased aspartate amino transferase (AST) activity of 4194 U/L and a mildly increased inorganic phosphorus concentration of 2.35 mmol/L. The foal was unresponsive to treatment and had to be euthanased. Skeletal musculature and the myocardium showed the most significant pathological changes, with histological evidence of rhabdomyolysis, whilst urine organic acid analysis and an abnormal organic acid serum profile were supportive of multiple acyl Co-A dehydrogenase deficiency typical of EAM. This is the first description of EAM in a non-domestic equid