A Gray-Level Dynamic Range Modification Technique for Image Feature Extraction Using Fuzzy Membership Function

The features of an image must be unique so it is necessary to use certain techniques to ensure them. One of the common techniques is to modify the gray dynamic range of an image. In principle, the gray level dynamic range modification maps the gray level ranges from the input image to the new gray level range as an output image using a specific function. Fuzzy Membership Function (MF) is one kind of membership function that applies the Fuzzy Logic concept. This study uses Trapezoidal MF to map the gray dynamic range of each RGB component to produce a feature of an RGB image. The aim of this study is how to ensure the uniqueness of image features through the setting of Trapezoidal MF parameters to obtain the new dynamic range of gray levels that minimize the possibility of other features other than the selected feature. To test the performance of the proposed method, it also tries to be applied to the signature image. Mean Absolute Error (MAE) calculations between feature labels are performed to test authentication between signatures. The results obtained are for comparison of samples of signature images derived from the same source having a much smaller MAE than the comparison of samples of signature images originating from different sources

Investigation of Dimethyl Ether Combustion Instabilities in a Partially - Premixed Gas Turbine Model Combustor Using High-Speed Laser Diagnostics

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140412/1/6.2014-0660.pd

The baroclinic instability in the context of layered accretion. Self-sustained vortices and their magnetic stability in local compressible unstratified models of protoplanetary disks

Turbulence and angular momentum transport in accretion disks remains a topic of debate. With the realization that dead zones are robust features of protoplanetary disks, the search for hydrodynamical sources of turbulence continues. A possible source is the baroclinic instability (BI), which has been shown to exist in unmagnetized non-barotropic disks. We present shearing box simulations of baroclinicly unstable, magnetized, 3D disks, in order to assess the interplay between the BI and other instabilities, namely the magneto-rotational instability (MRI) and the magneto-elliptical instability. We find that the vortices generated and sustained by the baroclinic instability in the purely hydrodynamical regime do not survive when magnetic fields are included. The MRI by far supersedes the BI in growth rate and strength at saturation. The resulting turbulence is virtually identical to an MRI-only scenario. We measured the intrinsic vorticity profile of the vortex, finding little radial variation in the vortex core. Nevertheless, the core is disrupted by an MHD instability, which we identify with the magneto-elliptic instability. This instability has nearly the same range of unstable wavelengths as the MRI, but has higher growth rates. In fact, we identify the MRI as a limiting case of the magneto-elliptic instability, when the vortex aspect ratio tends to infinity (pure shear flow). We conclude that vortex excitation and self-sustenance by the baroclinic instability in protoplanetary disks is viable only in low ionization, i.e., the dead zone. Our results are thus in accordance with the layered accretion paradigm. A baroclinicly unstable dead zone should be characterized by the presence of large-scale vortices whose cores are elliptically unstable, yet sustained by the baroclinic feedback. As magnetic fields destroy the vortices and the MRI outweighs the BI, the active layers are unmodified.Comment: 19+3 pages, 20+1 figures. Accepted by A&A, final versio

The second flight of the SUNRISE balloon-borne solar observatory: overview of instrument updates, the flight, the data and first results

The SUNRISE balloon-borne solar observatory, consisting of a 1~m aperture telescope that provided a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in June 2013. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg~{\sc ii}~k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000~\AA\ after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR~11768 observed relatively close to disk centre is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500~G and, while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.Comment: Accepted for publication in The Astrophysical Journa

Engineering Nanocomposite Membranes; Fabrication, Modification and Application

The engineering of novel membranes through fabrication and modification using engineered nanoscale materials (ENMs) presents tremendous opportunity within desalination and water treatment. This work presents an endeavour dedicated to investigate the design and fabrication of polymeric membranes and nanoscale materials. Also, to probe the role of nanoscale materials integration on the function of separating membranes aiming to diminish the propensity of the surface to foul.In the first part of the work, an attempt was made to research and compare the potential of versatile UF membranes structures in terms of morphology, surface characteristics and performance. The potential performance of the hand-made fabricated (UF) membranes was systematically evaluated against three organic model foulants with dissimilar origins; humic acid (HA), sodium alginate (NaAlg), and bovine serum albumin (BSA), under different initial feed concentration and pH chemistry. A diverse range of surface characteristics and morphologies have been produced as a result of varying the dope casting solution concentration, which corresponds to the wide range of commercially available UF membranes (6, 10, 35 and 100kDa). Also, a disparate fouling behaviour was observed depending on the membrane characteristics and the organic model foulant used. A one or more pore blocking mechanism were distinctly observed depending on the UF membrane cut-off used.Subsequently, the research presented the development of a novel nanocomposite membrane incorporating antimicrobial nanoparticles which have the potential to lower membrane biofouling. Antibacterial hybrid nanostructures (HNS) comprising of Ag decorated MWCNTs were successfully synthesised with the assistance of microwave irradiation. The HNS were then employed to fabricated antibacterial nanocomposite membranes via the classical phase inversion technique in order to assess their antimicrobial properties against two bacterial species; E. coli and S. aureus. The nanocomposite membranes remarkably displayed antibacterial activity (4.24 and 2.9 log kill) against the two species respectively. A higher stability under crossflow conditions was also demonstrated.Finally, for desalination applications, novel HNS comprising of a mussel-inspired PDA coated M/MO–MWCNTs, were successfully synthesised and used to fabricate TFN membranes. For comparison, four different M/MO (Al2O3, Fe2O3, TiO2 and Ag) nanoparticles (NPs) were in situ synthesised/loaded on the surface of CNTs, and the resultant HNS were further coated with a thin polymeric film of PDA. An intermediate layer of the HNS was then deposited on a PES substrate membrane, and an interfacial polymerisation (IP) process was carried out to render a polyamide (PA) thin layer above the intermediate layer. Both HNS and TFN were characterised using different characterisation tools, and the performance of nanofiltration (NF) membranes was evaluated against monovalent, divalent salts and heavy metal solutions. The fabricated TFN-NF membranes had higher performance in terms of their permeation characteristics compared to the thin film composite TFC membrane (⁓9.6-11.6 LMH), while maintaining their selectivity (≥91%) against both monovalent and divalent salts solutions, and (> 92%) against the multi-component heavy metal solution. The experimental results disclosed a high retention capability for TFC and TFN membranes along with greater potential stability/compatibility within the polymeric PA matrix. This implies that the NF membranes fabricated in this work can be employed for water reclamation purposes

Experience with the Hubble Space Telescope: 20 years of an archetype

The Hubble Space Telescope's mission is summarized, with special emphasis placed on the Space Telescope Science Institute's unique experience with Hubble's behavior as an astronomical telescope in the environment of low earth orbit for over two decades. Historical context and background are given, and the project's early scientific expectations are described. A general overview of the spacecraft is followed by a more detailed look at the optical design, both as intended and as built. Basic characteristics of the complete complement of science instruments are also summarized. Experience with the telescope on-orbit is reviewed, starting with the major initial problems, solutions, human servicing missions, and the associated expansion of the observatory's capabilities over this time. Specific attention is then given to understanding Hubble's optical quality and pointing/jitter performance, two fundamental characteristics of a telescope. Experience with-and the important mitigation of-radiation damage and contamination is also related. Beyond the telescope itself, the advances in data reduction, calibration, and observing techniques are briefly discussed, as well as the subsequent emergence of highly accessible high-level archival science products. Hubble's scientific impact concludes the discussion.Comment: Also found at http://www.stsci.edu/institute/org/telescopes/Reports/LalloOE2012.pd