120 research outputs found
PORTRAIT OF A MAN
You should\u27ve been admiring the brilliant world, the pouring dictionaries but instead I pass the men\u27s parliament At the check-out, he repeats the machine\u27s instructions which I click, passed to and fro between us like a precious bab
Development of a direct metalisation method for micro-engineering
This research concentrates on the establishment of a metalisation and micro-patterning
technique that eliminates metal evaporation and/or photoresist molding procedures.
The process design is chosen from the analysis of the broad field of direct metalisation
techniques where novel photocatalysts or photoreducing agents are increasingly
employed to create new processes.
The new photolithographic process in this study introduces two novel photoreducing
agents for additive metal thin film fabrication: methoxy poly(ethylene glycol) and
photosystem I. This work proves the concept of using light energy to directly reduce
metal ions incorporated within an ion-exchanged polyimide substrate to produce metal
thin films. The patterning step can be operated at atmospheric pressure, in a dry
environment, using a coating of the photoreducing agent. This process offers a
significant improvement to prior related work that relied on a water layer to enable the
metalisation. Of particular importance for this process is the influence of light energy
dose and heat treatment, which promote silver nanoparticles growth at the cost of
degradation of the substrate polymer. The investigation was carried out thoroughly by
laser writing experiments for a selected range of laser power and scan speed. To
complement the phenomenon observed in the laser experiments, prolonged UV light
exposure time and heat treatment experiments were carried out to confirm the
hypothesis postulated in this thesis.
The morphology of the silver nanoparticles produced, the changes of the substrate
surface and the adhesion of electroless plating were characterised. Results indicate that
UV irradiation with the energy density required for reasonable production speed causes
inevitable molecular damage to the polymer substrate. Photosystem I was found to be
able to catalyse the production of visually similar silver thin film by light sources in the
blue region. Using a similar light intensity, the exposure time was reduced by an order
of magnitude whilst the degradation phenomenon observed during the UV process
appears to be eradicated. With the fundamentals of the process established in this
thesis, future optimization is suggested for the transition from a proof of concept to
industrial implementation
PENERAPAN MODEL PEMBELAJARAN PROBLEM SOLVING DALAM MATERI PERBAIKAN SISTEM PENDINGIN
Penelitian ini bertujuan untuk mengetahui efektivitas model pembelajaran problem solving pada Materi Perbaikan Sistem Pendinginan di SMK Karsa Mulya Palangka Raya. Penelitian ini menggunakan pendekatan deskriptif kuantitatif dengan jumlah sampel 23 siswa. Instrumen yang digunakan adalah lembar observasi aktivitas siswa, angket respon siswa, dan tes hasil belajar. Hasil penelitian menunjukkan bahwa pembelajaran problem solving membuat siswa lebih aktif dalam kegiatan pembelajaran. Dari angket respon siswa diperoleh 82,07% siswa menyatakan sangat setuju penerapan model pembelajaran problem solving. Hasil belajar siswa dengan penerapan model pembelajaran problem solving pada Materi Perbaikan Sistem Pendinginan terdapat peningkatan hasil belajar dengan nilai rata--rata sebesar 73,61 dan persentase kelulusan sebesar 91.30%
Local Metric Learning in 2D/3D Deformable Registration With Application in the Abdomen
In image-guided radiotherapy (IGRT) of disease sites subject to respiratory motion, soft tissue deformations can affect localization accuracy. We describe the application of a method of 2D/3D deformable registration to soft tissue localization in abdomen. The method, called registration efficiency and accuracy through learning a metric on shape (REALMS), is designed to support real-time IGRT. In a previously developed version of REALMS, the method interpolated 3D deformation parameters for any credible deformation in a deformation space using a single globally-trained Riemannian metric for each parameter. We propose a refinement of the method in which the metric is trained over a particular region of the deformation space, such that interpolation accuracy within that region is improved. We report on the application of the proposed algorithm to IGRT in abdominal disease sites, which is more challenging than in lung because of low intensity contrast and nonrespiratory deformation. We introduce a rigid translation vector to compensate for nonrespiratory deformation, and design a special region-of-interest around fiducial markers implanted near the tumor to produce a more reliable registration. Both synthetic data and actual data tests on abdominal datasets show that the localized approach achieves more accurate 2D/3D deformable registration than the global approach
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AAPM medical physics practice guideline 10.a.: Scope of practice for clinical medical physics.
The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose primary purposes are to advance the science, education, and professional practice of medical physics. The AAPM has more than 8000 members and is the principal organization of medical physicists in the United States. The AAPM will periodically define new practice guidelines for medical physics practice to help advance the science of medical physics and to improve the quality of service to patients throughout the United States. Existing medical physics practice guidelines will be reviewed for the purpose of revision or renewal, as appropriate, on their fifth anniversary or sooner. Each medical physics practice guideline (MPPG) represents a policy statement by the AAPM, has undergone a thorough consensus process in which it has been subjected to extensive review, and requires the approval of the Professional Council. The medical physics practice guidelines recognize that the safe and effective use of diagnostic and therapeutic radiation requires specific training, skills, and techniques as described in each document. As the review of the previous version of AAPM Professional Policy (PP)-17 (Scope of Practice) progressed, the writing group focused on one of the main goals: to have this document accepted by regulatory and accrediting bodies. After much discussion, it was decided that this goal would be better served through a MPPG. To further advance this goal, the text was updated to reflect the rationale and processes by which the activities in the scope of practice were identified and categorized. Lastly, the AAPM Professional Council believes that this document has benefitted from public comment which is part of the MPPG process but not the AAPM Professional Policy approval process. The following terms are used in the AAPM's MPPGs: Must and Must Not: Used to indicate that adherence to the recommendation is considered necessary to conform to this practice guideline. Should and Should Not: Used to indicate a prudent practice to which exceptions may occasionally be made in appropriate circumstances
HALOGAS observations of NGC 4414: fountains, interaction, and ram pressure
We present deep H I imaging of the nearby spiral galaxy NGC 4414, taken as part of the Westerbork HALOGAS (Hydrogen Accretion in LOcal GAlaxieS) survey. The observations show that NGC 4414 can be characterized by a regularly rotating inner H I disk, and a more disturbed outer disk. Modeling of the kinematics shows that the outer disk is best described by a U-shaped warp. Deep optical imaging also reveals the presence of a low surface brightness stellar shell, indicating a minor interaction with a dwarf galaxy at some stage in the past. Modeling of the inner disk suggests that about 4 percent of the inner H I is in the form of extra-planar gas. Because of the disturbed nature of the outer disk, this number is difficult to constrain for the galaxy as a whole. These new, deep observations of NGC 4414 presented here show that even apparently undisturbed galaxies are interacting with their environment
2D/3D image registration using regression learning
In computer vision and image analysis, image registration between 2D projections and a 3D image that achieves high accuracy and near real-time computation is challenging. In this paper, we propose a novel method that can rapidly detect an object’s 3D rigid motion or deformation from a 2D projection image or a small set thereof. The method is called CLARET (Correction via Limited-Angle Residues in External Beam Therapy) and consists of two stages: registration preceded by shape space and regression learning. In the registration stage, linear operators are used to iteratively estimate the motion/deformation parameters based on the current intensity residue between the target projec-tion(s) and the digitally reconstructed radiograph(s) (DRRs) of the estimated 3D image. The method determines the linear operators via a two-step learning process. First, it builds a low-order parametric model of the image region’s motion/deformation shape space from its prior 3D images. Second, using learning-time samples produced from the 3D images, it formulates the relationships between the model parameters and the co-varying 2D projection intensity residues by multi-scale linear regressions. The calculated multi-scale regression matrices yield the coarse-to-fine linear operators used in estimating the model parameters from the 2D projection intensity residues in the registration. The method’s application to Image-guided Radiation Therapy (IGRT) requires only a few seconds and yields good results in localizing a tumor under rigid motion in the head and neck and under respiratory deformation in the lung, using one treatment-time imaging 2D projection or a small set thereof
SHIELD: Comparing Gas and Star Formation in Low Mass Galaxies
We analyze the relationships between atomic, neutral hydrogen (HI) and star formation (SF) in the 12 low-mass SHIELD galaxies. We compare high spectral (~0.82 km/s/channel) and spatial resolution (physical resolutions of 170 pc - 700 pc) HI imaging from the VLA with H\alpha and far-ultraviolet imaging. We quantify the degree of co-spatiality between star forming regions and regions of high HI column densities. We calculate the global star formation efficiencies (SFE, / ), and examine the relationships among the SFE and HI mass, HI column density, and star formation rate (SFR). The systems are consuming their cold neutral gas on timescales of order a few Gyr. While we derive an index for the Kennicutt-Schmidt relation of N ~ 0.68 0.04 for the SHIELD sample as a whole, the values of N vary considerably from system to system. By supplementing SHIELD results with those from other surveys, we find that HI mass and UV-based SFR are strongly correlated over five orders of magnitude. Identification of patterns within the SHIELD sample allows us to bin the galaxies into three general categories: 1) mainly co-spatial HI and SF regions, found in systems with highest peak HI column densities and highest total HI masses, 2) moderately correlated HI and SF regions, found in systems with moderate HI column densities, and 3) obvious offsets between HI and SF peaks, found in systems with the lowest total HI masses. SF in these galaxies is dominated by stochasticity and random fluctuations in their ISM
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