Microstructurally based variations on the dwell fatgue life of titanium alloy IMI 834

An experimental study was undertaken to determine the role of microstructure on the fatigue life reduction observed in titanium alloy IMI 834 under dwell loading conditions. The wave forms compared were a trapezoid with 15 and 30 second hold times at the maximum test load and a baseline, 10 Hertz, haversine. The stress ratio for both loading wave forms was 0.10. The fatigue loading of each specimen was conducted in a vacuum within a scanning electron microscope chamber which minimized the possibility that the laboratory environment would adversely affect the material behavior. Two microstructural conditions were investigated in the experimental program. The first involved standard 'disk' material with equiaxed alpha in a transformed beta matrix. The second material was cut from the same disk forging as the first but was heat treated to obtain a martensitic alpha prime microstructure. Tensile tests were performed prior to the onset of the fatigue loading portion of the study, and it was determined that the yield strengths of the specimens from both material conditions were within ten percent. The maximum fatigue loads were chosen to be 72 percent of the average yield strength for both materials as determined from the tensile tests. It was found that the cycles to failure from the 10 Hertz loading wave form were reduced by a factor of approximately five when the loading was changed to the trapezoidal wave form for the standard 'disk' material. The fatigue life reduction for the martensitic structure under identical test conditions was approximately 1.75. The improvement observed with the martensitic structure also was accompanied by an increase in overall fatigue life for the wave forms tested. This paper will review the results and conclusions of this effort

The Distance to the Coma Cluster from Surface Brightness Fluctuations

We report on the first determination of the distance to the Coma Cluster based on surface brightness fluctuation (SBF) measurements obtained from Hubble Space Telescope WFPC2 observations of the bright E0 galaxy NGC 4881 in the Coma Cluster and ground-based observations of the standard E1 galaxy NGC 3379 in the Leo-I group. Relative distances based on the I-band fluctuation magnitude, I(SBF), are strongly dependent on metallicity and age of the stellar population. However, the radial changes in the stellar populations of the two giant ellipticals, NGC 3379 and NGC 4881, are well described by published Mg_2 gradients, and the ground-based measurements of I(SBF) at several radial points in NGC 3379 are used to calibrate I(SBF) in terms of the Mg_2 index. The distance to NGC 3379, assumed to be identical to the average SBF distance of the Leo-I group, is combined with the new SBF measurements of NGC 4881 to obtain a Coma Cluster distance of 102+-14 Mpc. Combining this distance with the cosmic recession velocity of Coma (7186+-428 km/s), we find the Hubble constant to be H_0 = 71+-11 km/s/Mpc.Comment: 12 pages, LaTex, includes aaspp4.sty and 3 eps figures. To appear in ApJ Letter

Evaluation of Serodiagnostic Assays for Mycobacterium bovis

In 2011, the United States Department of Agriculture conducted a project in which elk (Cervus elaphus spp.), white-tailed deer (WTD) (Odocoileus virginianus), and reindeer (Rangifer tarandus) were evaluated by the single cervical tuberculin test (SCT), comparative cervical tuberculin test (CCT), and serologic tests. The rapid antibody detection tests evaluated were the CervidTB Stat-Pak (Stat-Pak), and the Dual Path Platform VetTB (DPP). Blood was collected from presumably uninfected animals prior to tuberculin injection for the SCT. A total of 1,783 animals were enrolled in the project. Of these, 1,752 (98.3%) were classified as presumably uninfected, based on originating from a captive cervid herd with no history of exposure to TB. Stat-Pak specificity estimates were 92.4% in reindeer, 96.7% in WTD, and 98.3% in elk and were not significantly different from SCT specificity estimates. Using the DPP in series on Stat-Pak antibody-positive samples improved specificity in the three species. Thirty one animals were classified as confirmed infected, based on necropsy and laboratory results, and 27/31 were antibody positive on Stat-Pak for an estimated sensitivity of 87.1%. The study findings indicate that rapid serologic tests used in series are comparable to the SCT and CCT and may have a greater ability to detect TB-infected cervids

Drawing Boundaries

In “On Drawing Lines on a Map” (1995), I suggested that the different ways we have of drawing lines on maps open up a new perspective on ontology, resting on a distinction between two sorts of boundaries: fiat and bona fide. “Fiat” means, roughly: human-demarcation-induced. “Bona fide” means, again roughly: a boundary constituted by some real physical discontinuity. I presented a general typology of boundaries based on this opposition and showed how it generates a corresponding typology of the different sorts of objects which boundaries determine or demarcate. In this paper, I describe how the theory of fiat boundaries has evolved since 1995, how it has been applied in areas such as property law and political geography, and how it is being used in contemporary work in formal and applied ontology, especially within the framework of Basic Formal Ontology

A randomised controlled trial of cognitive behavioural treatment for obsessive compulsive disorder in children and adolescents

Cognitive behaviour therapy (CBT) for young people with obsessive compulsive disorder (OCD) has become the treatment of first choice. However, the literature is largely based on studies emphasising exposure and response prevention. In this study, we report on a randomised controlled trial of CBT for young people carried out in typical outpatient clinic conditions which focused on cognitions. A randomised controlled trial compares 10 sessions of manualised cognitive behavioural treatment with a 12-week waiting list for adolescents and children with OCD. Assessors were blind to treatment allocation. 21 consecutive patients with OCD aged between 9 and 18 years were recruited. The group who received treatment improved more than a comparison group who waited for 3 months. The second group was treated subsequently using the same protocol and made similar gains. In conclusion, CBT can be delivered effectively to young people with OCD in typical outpatient settings

Self-Assembly of ABC Bottlebrush Triblock Terpolymers with Evidence for Looped Backbone Conformations

Bottlebrush block copolymers offer rich opportunities for the design of complex hierarchical materials. As consequences of the densely grafted molecular architecture, bottlebrush polymers can adopt highly extended backbone conformations and exhibit unique physical properties. A recent report has described the unusual phase behavior of ABC bottlebrush triblock terpolymers bearing grafted poly(dl-lactide) (PLA), polystyrene (PS), and poly(ethylene oxide) (PEO) blocks (LSO). In this work, a combination of resonant soft X-ray reflectivity (RSoXR), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), and self-consistent field theory (SCFT) was used to provide insight into the phase behavior of LSO and underlying backbone chain conformations. Consistent with SCFT calculations, RSoXR measurements confirm a unique mesoscopic ACBC domain connectivity and decreasing lamellar periods (d0) with increasing backbone length of the PEO block. RSoXR and NEXAFS demonstrate an additional unusual feature of brush LSO thin films: when the overall film thickness is ∼3.25d0, the film–air interface is majority PS (>80%). Because PS is the midblock, the triblocks must adopt looping configurations at the surface, despite the preference for the backbone to be extended. This result is supported by backbone concentrations calculated through SCFT, which suggest that looping midblocks are present throughout the film. Collectively, this work provides evidence for the flexibility of the bottlebrush backbone and the consequences of low-χ block copolymer design. We propose that PEO blocks localize at the PS/PLA domain interfaces to screen the highest χ contacts in the system, driving the formation of loops. These insights introduce a potential route to overcome the intrinsic penalties to interfacial curvature imposed by the bottlebrush architecture, enabling the design of unique self-assembled materials

Recent trends and developments in pyrolysis-gas chromatography: review

Pyrolysis-gas chromatography (Py-GC) has become well established as a simple, quick and reliable analytical technique for a range of applications including the analysis of polymeric materials. Recent developments in Py-GC technology and instrumentation include laser pyrolysis and non-discriminating pyrolysis. Progress has also been made in the detection of low level polymer additives with the use of novel Py-GC devices. Furthermore, it has been predicted that future advances in separation technology such as the use of comprehensive two-dimensional gas chromatography will further enhance the analytical scope of Py-GC

A unique therapeutic approach to emesis and itch with a proanthocyanidin-rich genonutrient

<p>Abstract</p> <p>Background</p> <p>We examined the therapeutic potential of a proprietary <it>Croton palanostigma </it>extract (Zangrado^®) in the management of emesis and itch.</p> <p>Methods</p> <p>Emesis was induced in ferrets with morphine-6-glucuronide (0.05 mg/kg sc) in the presence of Zangrado (3 mg/kg, ip) and the cannabinoid receptor 1 antagonist, AM 251 (5 mg/kg, ip). Topical Zangrado (1%) was assessed for anti-pruretic actions in the 5-HT-induced scratching model in rats and evaluated in capsaicin-induced gastric hyperemia as measured by laser doppler flow. In the <it>Apc</it>^<it>Min</it>mouse model of precancerous adenomatosis polyposis, mice received Zangrado (100 μg/ml in drinking water) from the age of 6 – 16 weeks for effects on polyp number. In RAW 264.7 cells Zangrado was examined for effects on lipopolysaccharide-induced nitrite production.</p> <p>Results</p> <p>Zangrado was a highly effective anti-emetic, reducing morphine-induced vomiting and retching by 77%. These benefits were not associated with sedation or hypothermia and were not reversed by cannabinoid receptor antagonism. Itch responses were blocked in both the morphine and 5-HT models. Zangrado did not exacerbate the <it>Apc</it>^<it>Min</it>condition rather health was improved. Capsaicin-induced hyperemia was blocked by Zangrado, which also attenuated the production of nitric oxide by activated macrophages.</p> <p>Conclusion</p> <p>Zangrado is an effective anti-emetic and anti-itch therapy that is devoid of common side-effects, cannabinoid-independent and broadly suppresses sensory afferent nerve activation. This complementary medicine represents a promising new approach to the management of nausea, itch and irritable bowel syndrome.</p