Coated Feedstock for Fabrication of Ceramic Parts by CAM-LEM

In laminated object manufacturing of ceramic components, lamination is one of the most important materials issues. Good lamination ensures monolithic component after firing. Otherwise, lamination defects that inevitably will occur in the parts will affect the properties of ceramic components. Adhesive (both liquid and non-liquid) lamination processes were developed for the cut-then-stack (CAM-LEM) procedure. The non-liquid adhesive lamination is discussed in detail.Mechanical Engineerin

Analytical study of level crossings in the Stark-Zeeman spectrum of ground state OH

The ground electronic, vibrational and rotational state of the OH molecule is currently of interest as it can be manipulated by electric and magnetic fields for experimental studies in ultracold chemistry and quantum degeneracy. Based on our recent exact solution of the corresponding effective Stark-Zeeman Hamiltonian, we present an analytical study of the crossings and avoided crossings in the spectrum. These features are relevant to non-adiabatic transitions, conical intersections and Berry phases. Specifically, for an avoided crossing employed in the evaporative cooling of OH, we compare our exact results to those derived earlier from perturbation theory.Comment: 5 figures, to be published in Eur. Phys. J.

Reinforced hetero-normativity: gender constructs in Chosŏn (朝鮮) Korea

During Korea’s Chosŏn dynasty (朝鮮; 1392-1910), strictly codified heteronormalising gender constructs emerged, which for all intents and purposes undermined the possibility of homosexuality to exist in either private or public spaces. By drawing on contemporary critical theorists such as Hélène Cixous and Luce Irigaray, this paper critiques the socio-historical constructs of gender identity in Korea shaped during this period. Such critiques expose the inherent inequalities of hierarchical ‘gender traditions’ that are reinforced through patriarchies, which in the case of Chosŏn, commemorated the patrilineal genealogies of (supposedly) heterosexual men from the past. I will begin by dismantling notions of gender during this period, which was manipulated and rigidly constructed by (mis)using Neo-Confucian texts and metaphysics, inherited from the Chinese philosopher Zhu Xi (朱熹, 1130-1200). Zhu’s Reflections on Things at Hand, sought to regulate the family, while his Lesser Learning, reiterated rules that facilitated the suppression of women as daughters, wives, and even mothers. While commemorating ‘great men’ and emphasising ideals of ‘good women’, a gender ideology was implanted within the social matrix and recorded from one generation to the next in genealogical records known as chokpo (族譜). This hetero-normative way-of-being was enforced in legal texts and through literature by men, which yoked women into artificially orchestrated modes of behaviour that would also be transmitted by women themselves via texts that they themselves sometimes wrote and distributed. These ideas continue to influence modern Korean society, where women still struggle to dismantle out-dated modes of social expectations, and where the LGBTQ community is only starting to assert themselves and reject ‘compulsive’ hetero-normativity

Fusion of multi-view ultrasonic data for increased detection performance in non-destructive evaluation

State-of-the-art ultrasonic non-destructive evaluation (NDE) uses an array to rapidly generate multiple, information-rich views at each test position on a safety-critical component. However, the information for detecting potential defects is dispersed across views, and a typical inspection may involve thousands of test positions. Interpretation requires painstaking analysis by a skilled operator. In this paper, various methods for fusing multi-view data are developed. Compared with any one single view, all methods are shown to yield significant performance gains, which may be related to the general and edge cases for NDE. In the general case, a defect is clearly detectable in at least one individual view, but the view(s) depends on the defect location and orientation. Here, the performance gain from data fusion is mainly the result of the selective use of information from the most appropriate view(s) and fusion provides a means to substantially reduce operator burden. The edge cases are defects that cannot be reliably detected in any one individual view without false alarms. Here, certain fusion methods are shown to enable detection with reduced false alarms. In this context, fusion allows NDE capability to be extended with potential implications for the design and operation of engineering assets

Spinal cord atrophy as a primary outcome measure in phase II trials of progressive multiple sclerosis (vol 23, pg 1, 2017)

Cawley N, Tur C, Prados F, et al. Spinal cord atrophy as a primary outcome measure in phase II trials of progressive multiple sclerosis. Mult Scler. Epub ahead of print 18 May 2017. DOI: 10.1177/1352458517709954. On page 9 of this article, the Declaration of Conflicting Interests and Funding statements were incorrect. The correct declarations are shown below

Stressed Oxidation of C/SiC Composites

Constant load, stressed oxidation testing was performed on T-300 C/SiC composites with a SiC seal coat. Test conditions included temperatures ranging from 350 C to 1500 C at stresses of 69 MPa and 172 MPa (10 and 25 ksi). The coupon subjected to stressed oxidation at 550 C/69 MPa for 25 hours had a room temperature residual strength one-half that of the as-received coupons. The coupon tested at the higher stress and all coupons tested at higher temperatures failed in less than 25 hr. Microstructural analysis of the fracture surfaces, using SEM (scanning electron microscopy), revealed the formation of reduced cross-sectional fibers with pointed tips. Analysis of composite cross-sections show pathways for oxygen ingress. The discussion will focus on fiber/matrix interphase oxidation and debonding as well as the formation and implications of the fiber tip morphology

Oxidation of Carbon/Carbon through Coating Cracks

Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasona

Search for gamma-rays from M31 and other extragalactic objects

Although the existence of fluxes of gamma-rays of energies 10 to the 12th power eV is now established for galactic sources, the detection of such gamma-rays from extragalactic sources has yet to be independently confirmed in any case. The detection and confirmation of such energetic photons is of great astrophysical importance in the study of production mechanisms for cosmic rays, and other high energy processes in extragalactic objects. Observations of m31 are discussed. It is reported as a 10 to the 12th power eV gamma-ray source. Flux limits on a number of other extragalactic objects chosen for study are given

Search for gamma-rays above 400 GeV from Geminga

Observations of Geminga made at the Whipple Observatory using the atmospheric Cherenkov technique during the moonless periods of November 1983 to February 1984 and November 1984 till February 1985 were examined for evidence for the emission of gamma rays with energy in excess of approx 400 GeV. Evidence of either a steady flux or a flux pulsed with a period near 60 seconds were studied. In neither case was any significant effect observed, enabling the establishment 3 of sigma upper limits of 5.5 x 10 to the -11th power photons/sq cm/s and 2.0 x 10 to the -11th power photons/sq cm/s for the steady and pulsed emission respectively. The limit to the pulsed flux is approximately a factor of six below that predicted