1,260 research outputs found
Time Dependent 3-D Simulation of a DC Non-Transferred Arc Plasma Torch: Anode Attachment and Downstream Region Effects
No full textThe aim of this work is to investigate by means of a 3-D time-dependent numerical model the plasma flow and heat transfer inside a DC non-transferred arc plasma torch operating at atmospheric pressure, using a customized version of the CFD commercial code FLUENT
Time Dependent 3-D Numerical Simulation of Transferred Arc Plasma Treatment
No full textA 3-D time-dependent numerical model useful for the analysis of a dc transfered argon arc has ben developed. The model allows to investigate the influence on behaviour the arc and on the evolution of the temperature distribution inside the anode of an external magnetic field induced by a curent flowing in a moving leading wire parallel to the axis of the cathode. If the current of the arc and the current of the external conductor have opposite directions, magnetic fields mutually repel and the arc is deflected losing its natural axisymmetric configuration. This practice to obtain a deflected arc may find applications as in surface treatment of metallic substrates
3-D Turbulent Modelling of an ICPT with Detailed Gas Injection Section
No full textThe aim of this work is to investigate in a realistic manner the behaviour of inductively coupled plasma torches operating at atmospheric pressure, by means of an improved turbulent version of the 3-D model based on customized CFD commercial code FLUENT© previously used to describe configurations with simplified gas inlet section
Surgical and Post-surgical Evaluation of Epilepsy.
No full textIn drug-resistant epilepsy (DRE) patients, the aim of epilepsy surgery is to remove or disconnect the epileptogenic zone (EZ) without producing additional neurological or cognitive deficits.
An extensive pre-surgical investigation is needed in order to identify and delineate the extension of the EZ, which is defined as “the site of the beginning of the epileptic seizures and of their primary organisation.” In this setting, clinical neuroradiology plays a crucial role in establishing diagnoses and selecting patients for surgery. Surgical outcome is better if a structural lesion is identified by magnetic resonance imaging (MRI) that is the radiological technique of choice for pre-surgical assessment. When MRI shows lesions that are accessible and congruent with the noninvasive electroclinical data, patients (particularly children) should be considered for surgery early on. When MRI does not identify a lesion, or the lesion is ill-defined or located close to eloquent brain areas, a more extensive pre-surgical evaluation is needed, which may involve computational analysis of MRI data, invasive electroencephalography, such as stereo-electroencephalography (SEEG), and functional imaging. Ictal SPECT, postictal perfusion MRI, and simultaneous EEG-fMRI can assist in the identification of the EZ. Interictal 18F-FDG PET or perfusion MRI shows the functional deficit zone. Eloquent brain areas are visualized by task-related fMRI and white matter bundles by diffusion tractography (DTI). Multimodal integration of structural and functional imaging is used to build up the complete surgical scene.
MRI is performed in post-surgical follow-up to evaluate the completeness of the resection and to monitor potentially growing lesions, while fMRI and diffusion tractography are used to monitor patients with post-surgical deficits
Typescript Bill H.R. 20819 for the Construction of Roads and other Permanent Improvements
No full textTypescript draft of Bill H.R. 20819 to provide for the construction of roads and other permanent improvements at or near the Grand Canyon. The sum of $110,000 dollars is to be appropriated for the project under the direction of the Secretary of Agriculture
3-D Simulation of Powder Injection in Various ICPT Configurations
No full textIn this paper, numerical simulations of the trajectory and heating history of powders injected through a carrier gas in inductively coupled plasma torches working at atmospheric pressure have been performed within a fully 3-D FLUENT©-based model, taking into account the effects of plasma-particle interaction and the turbulent dispersion of the particles, in the frame of a stochastic approach
3-D Modelling of DC Transferred arc Twin Torch for Asbestos Inertization
No full textThe aim of this work is to investigate by means of a 3-D numerical
model the fluid flow and temperature distribution of a plasma transferred electric arc discharge generated between two suspended metallic electrodes. This twin torch device is used inside a plasma furnace for hazardous waste incineration and asbestos inertization. Flow and energy equations are solved for an optically thin plasma under conditions of LTE, while the electromagnetic field equations are solved in their scalar and vector potential form. Electrodes interfaces are taken into account using a simplified approach, imposing a current density distribution on the cathode surface. The anode and cathode regions are discretized in their detailed design, in order to better understand the effects of their geometries on the discharge behavior. Turbulence effects are taken into account into the model using a RANS approach, as well as the effect on the discharge characteristics of using different types of plasma gas (Ar and Ar/H2 mixtures), for various geometric and operating conditions. Results are presented in order to characterize the fluid flow and the temperature field of this kind of device. Simulations are performed using a customized CFD commercial code FLUENT°R , parallelized over a network cluster of double processor calculators in order to use the full capabilities of the 3-D modelling code
3-D Fluidynamic and Plasma Characterization of DC Transferred Arc Plasma Torches for Metal Cutting
No full textThe aim of this work is to investigate by means of a 3-D numerical model the behaviour of a transferred arc plasma torch operating at atmospheric pressure, for the cutting of a metallic substrate material, using a customized version of the CFD commercial code FLUENT©. The metallic substrate and the keyhole are included in the computational domain in order to take into account their effects on the flow field of the discharge at the nozzle exit. The detailed gas injection section and the cathode chamber are included in the computational domain as well
Innovative Ways of Dealing with Existing Problems: How to reliably Assess the Cause of Damage of Masonry Structures in an Area with Man-induced Earthquakes?
No full textGroningen, a province in the northern part of the Netherlands, suffers from earthquakes because of gas drilling. The residential building stock in Groningen was not designed for these loads. Over the years a lot of smaller and larger damage has developed, possibly - but not necessarily - caused by the effects of gas drilling. Delft University of Technology was asked by the Dutch government to come up with a method to reliably assess the cause of damage of masonry structures in Groningen. This paper discusses the developed approach for reliably assessing the causes of failure of masonry structures in earthquake-prone areas and the way innovative monitoring techniques were applied.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Mechanic
Efficient material use through smart flexible formwork method
No full textConcrete is an excellent material for application in free-form architecture as a result of its initial fluid state. Double-curved building shapes have been realized in various fibre-reinforced mixtures, using advanced CNC-milled formwork systems. However, a substantial reduction of material use is still possible on two ends: by using a flexible formwork very thin and structurally efficient elements can be manufactured, reinforced with fibres or textiles. Moreover, the reusability of the flexible formwork considerably limits the waste material that was always remaining after the use of milled formwork systems. This paper discusses experiments with both formwork and mixtures in a PhD-study of the first author, demonstrating the ecological potential of this innovative production method.Structural EngineeringCivil Engineering and Geoscience
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