Study of manufacturing and measurement reproducibility on a laser textured structured surface

In recent years there has been increasing interest in the use of structured surfaces to provide specific functional performance. Such surfaces often consist of localised micro-scale surface features with predetermined geometries. The performance of the feature manufacturing process affects the functional performance of the surface, and can be assessed by measurement of the resulting surface features. Measurement of the resulting micromanufactured surface features necessitates use of areal optical surface topography instruments. However, conventional characterisation methods, based on areal surface texture parameters, often prove inadequate, and may fail to capture the relevant geometric properties needed for an effective dimensional verification. This paper investigates an alternative route to verification, based on the determination of geometric attributes of the microfabricated features. This approach allows for direct assessment of manufacturing process performance, by comparison of the geometric attributes with their nominal values. An example application is shown in which a micromachining process (laser texturing) is used to fabricate a periodic pattern of dimples, which provide a low friction bearing surface. In this paper, manufacturing process performance is assessed by characterisation of the diameter and out-of-roundness. Sources of uncertainty associated with these geometric parameters are also considered

Comparisons among ten models of acoustic backscattering used in aquatic ecosystem research

Author Posting. © Acoustical Society of America, 2015. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 138 (2015); 3742, doi:10.1121/1.4937607.Analytical and numerical scatteringmodels with accompanying digital representations are used increasingly to predict acoustic backscatter by fish and zooplankton in research and ecosystem monitoring applications. Ten such models were applied to targets with simple geometric shapes and parameterized (e.g., size and material properties) to represent biological organisms such as zooplankton and fish, and their predictions of acoustic backscatter were compared to those from exact or approximate analytical models, i.e., benchmarks. These comparisons were made for a sphere, spherical shell, prolate spheroid, and finite cylinder, each with homogeneous composition. For each shape, four target boundary conditions were considered: rigid-fixed, pressure-release, gas-filled, and weakly scattering. Target strength (dB re 1 m2) was calculated as a function of insonifying frequency (f = 12 to 400 kHz) and angle of incidence (θ = 0° to 90°). In general, the numerical models (i.e., boundary- and finite-element) matched the benchmarks over the full range of simulation parameters. While inherent errors associated with the approximate analytical models were illustrated, so were the advantages as they are computationally efficient and in certain cases, outperformed the numerical models under conditions where the numerical models did not convergeThis work was supported by the NOAA Fisheries Advanced Sampling Technologies Working Group, the Office of Naval Research, and the National Oceanic Partnership Program. Josiah S. Renfree

The Subaru-XMM-Newton Deep Survey (SXDS) VIII.: Multi-wavelength Identification, Optical/NIR Spectroscopic Properties, and Photometric Redshifts of X-ray Sources

We report the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV to the mid-IR. We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6micron, near-UV, and 24micron source catalogs as well as matching catalogs of AGN candidates selected in 1.4GHz radio and i'-band variability surveys. Once candidates of Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65\% of the X-ray AGN candidates are spectroscopically-identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilising the multi-wavelength photometric data of the large sample of X-ray selected AGNs, we evaluate the stellar masses, M*, of the host galaxies of the narrow-line AGNs. The distribution of the stellar mass is remarkably constant from z=0.1 to 4.0. The relation between M* and 2--10 keV luminosity can be explained with strong cosmological evolution of the relationship between the black hole mass and M*. We also evaluate the scatter of the UV-MIR spectral energy distribution (SED) of the X-ray AGNs as a function of X-ray luminosity and absorption to the nucleus. The scatter is compared with galaxies which have redshift and stellar mass distribution matched with the X-ray AGN. The UV-NIR SEDs of obscured X-ray AGNs are similar to those of the galaxies in the matched sample. In the NIR-MIR range, the median SEDs of X-ray AGNs are redder, but the scatter of the SEDs of the X-ray AGN broadly overlaps that of the galaxies in the matched sample.Comment: Accepted for publication in PASJ Subaru special issue. 42 pages, 22 figures. Entire contents of Tables 3, 8, 9, 10, and 11, and ASCII format tables are available from http://www.astr.tohoku.ac.jp/~akiyama/SXDS/index.htm

Mesoscale Eddies Are Oases for Higher Trophic Marine Life

Mesoscale eddies stimulate biological production in the ocean, but knowledge of energy transfers to higher trophic levels within eddies remains fragmented and not quantified. Increasing the knowledge base is constrained by the inability of traditional sampling methods to adequately sample biological processes at the spatio-temporal scales at which they occur

Surface texture measurement for additive manufacturing

The surface texture of additively manufactured metallic surfaces made by powder bed methods is affected by a number of factors, including the powder's particle size distribution, the effect of the heat source, the thickness of the printed layers, the angle of the surface relative to the horizontal build bed and the effect of any post processing/finishing. The aim of the research reported here is to understand the way these surfaces should be measured in order to characterise them. In published research to date, the surface texture is generally reported as an Ra value, measured across the lay. The appropriateness of this method for such surfaces is investigated here. A preliminary investigation was carried out on two additive manufacturing processes—selective laser melting (SLM) and electron beam melting (EBM)—focusing on the effect of build angle and post processing. The surfaces were measured using both tactile and optical methods and a range of profile and areal parameters were reported. Test coupons were manufactured at four angles relative to the horizontal plane of the powder bed using both SLM and EBM. The effect of lay—caused by the layered nature of the manufacturing process—was investigated, as was the required sample area for optical measurements. The surfaces were also measured before and after grit blasting

Genomics and Epigenetics of Malignant Mesothelioma

Malignant mesothelioma is an aggressive and lethal asbestos-related disease. Diagnosis of malignant mesothelioma is particularly challenging and is further complicated by the lack of disease subtype-specific markers. As a result, it is especially difficult to distinguish malignant mesothelioma from benign reactive mesothelial proliferations or reactive fibrosis. Additionally, mesothelioma diagnoses can be confounded by other anatomically related tumors that can invade the pleural or peritoneal cavities, collectively resulting in delayed diagnoses and greatly affecting patient management. High-throughput analyses have uncovered key genomic and epigenomic alterations driving malignant mesothelioma. These molecular features have the potential to better our understanding of malignant mesothelioma biology as well as to improve disease diagnosis and patient prognosis. Genomic approaches have been instrumental in identifying molecular events frequently occurring in mesothelioma. As such, we review the discoveries made using high-throughput technologies, including novel insights obtained from the analysis of the non-coding transcriptome, and the clinical potential of these genetic and epigenetic findings in mesothelioma. Furthermore, we aim to highlight the potential of these technologies in the future clinical applications of the novel molecular features in malignant mesothelioma

Identification and target strength of orange roughy (Hoplostethus atlanticus) measured in situ

It is often assumed that in situ target strength (TS) measurements from dispersed fish are representative of the surveyed schooling fish. For in situ TS measurements of orange roughy in deep water, it has been difficult to validate the target species, individual lengths, and tilt angles and how representative these are of schooling fish. These problems have been addressed by attaching an acoustic optical system (AOS) to a trawl net. The AOS enables in situ measurements of TS and volume backscattering strength (Sv) at 38 and 120 kHz with optical verification of species and stereo camera measurements of fish length and tilt angle. TS estimates believed representative of the schooling population were derived by (1) weighting the frequency-dependent TS values by the Sv frequency difference distribution of orange roughy schools and (2) weighting the in situ TS measurements with an assumed tilt angle distribution. The 120-kHz TS estimates were less sensitive to variations in frequency difference and tilt angle, suggesting that this frequency may be better for biomass estimates than 38 kHz, the traditional survey frequency. Computations performed with an anatomically detailed scattering model agree with measurements of TS at both frequencies over a range of tilt angles. © 2013 Acoustical Society of America

Comparisons among ten models of acoustic backscattering used in aquatic ecosystem research

The article of record as published may be found at https://doi.org/10.1121/1.4937607Analytical and numerical scatteringmodels with accompanying digital representations are used increasingly to predict acoustic backscatter by fish and zooplankton in research and ecosystem monitoring applications. Ten such models were applied to targets with simple geometric shapes and parameterized (e.g., size and material properties) to represent biological organisms such as zooplankton and fish, and their predictions of acoustic backscatter were compared to those from exact or approximate analytical models, i.e., benchmarks. These comparisons were made for a sphere, spherical shell, prolate spheroid, and finite cylinder, each with homogeneous composition. For each shape, four target boundary conditions were considered: rigid-fixed, pressure-release, gas-filled, and weakly scattering. Target strength (dB re 1 m2) was calculated as a function of insonifying frequency (f = 12 to 400 kHz) and angle of incidence (θ = 0° to 90°). In general, the numerical models (i.e., boundary- and finite-element) matched the benchmarks over the full range of simulation parameters. While inherent errors associated with the approximate analytical models were illustrated, so were the advantages as they are computationally efficient and in certain cases, outperformed the numerical models under conditions where the numerical models did not convergeThis work was supported by the NOAA Fisheries Advanced Sampling Technologies Working Group, the Office of Naval Research, and the National Oceanic Partnership Program. Josiah S. Renfree