5 results on '"Jacobs, Patric"'
Search Results
2. Surface Treatment.
- Author
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KOURKOULIS, STAVROS K., Cnudde, Veerle, Dierick, Manuel, Masschaele, Bert, and Jacobs, Patric JS.
- Abstract
The growth in the renovation and maintenance activities of old buildings has largely contributed to the success of water repellents and consolidants. The greatest difficulty however, is the selection of the most appropriate one out of this wide range of products. Although certain products can work splendidly on a certain stone type, they can be harmful to another, especially when they alter important petrophysical material characteristics. Therefore combined research is necessary on the properties of the conservation products in combination with the determination of some important technical and moisture transfer parameters of the stone material itself. Different traditional research techniques exist in order to determine these technical and moisture transfer properties. These traditional techniques, in combination with advanced 3D visualization techniques, like X-ray and high-speed neutron tomography, turn out to offer important additional information on both the stone material and on the transfer method of the conservation products inside the stone material. In this paper, results of traditional research in combination with data obtained from X-ray micro-CT and high-speed neutron tomography is given, as well as a comment on the recent developments in material research by means of tomography. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
3. Realistic 3D computer model of the gerbil middle ear, featuring accurate morphology of bone and soft tissue structures.
- Author
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Buytaert, Jan, Salih, Wasil, Dierick, Manual, Jacobs, Patric, Dirckx, Joris, Buytaert, Jan A N, Salih, Wasil H M, and Dirckx, Joris J J
- Abstract
In order to improve realism in middle ear (ME) finite-element modeling (FEM), comprehensive and precise morphological data are needed. To date, micro-scale X-ray computed tomography (μCT) recordings have been used as geometric input data for FEM models of the ME ossicles. Previously, attempts were made to obtain these data on ME soft tissue structures as well. However, due to low X-ray absorption of soft tissue, quality of these images is limited. Another popular approach is using histological sections as data for 3D models, delivering high in-plane resolution for the sections, but the technique is destructive in nature and registration of the sections is difficult. We combine data from high-resolution μCT recordings with data from high-resolution orthogonal-plane fluorescence optical-sectioning microscopy (OPFOS), both obtained on the same gerbil specimen. State-of-the-art μCT delivers high-resolution data on the 3D shape of ossicles and other ME bony structures, while the OPFOS setup generates data of unprecedented quality both on bone and soft tissue ME structures. Each of these techniques is tomographic and non-destructive and delivers sets of automatically aligned virtual sections. The datasets coming from different techniques need to be registered with respect to each other. By combining both datasets, we obtain a complete high-resolution morphological model of all functional components in the gerbil ME. The resulting 3D model can be readily imported in FEM software and is made freely available to the research community. In this paper, we discuss the methods used, present the resulting merged model, and discuss the morphological properties of the soft tissue structures, such as muscles and ligaments. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
4. The ~4-ka Rungwe Pumice (South-Western Tanzania): a wind-still Plinian eruption.
- Author
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Fontijn, Karen, Ernst, Gerald, Bonadonna, Costanza, Elburg, Marlina, Mbede, Evelyne, and Jacobs, Patric
- Subjects
VOLCANIC eruptions ,PUMICE ,VOLCANIC ash, tuff, etc. ,TRACHYTE - Abstract
The ~4-ka trachytic Rungwe Pumice (RP) deposit from Rungwe Volcano in South-Western Tanzania is the first Plinian-style deposit from an African volcano to be closely documented focusing on its physical characterization. The RP is a mostly massive fall deposit with an inversely graded base. Empirical models suggest a maximum eruption column height H of 30.5-35 km with an associated peak mass discharge rate of 2.8-4.8 × 10 kg/s. Analytical calculations result in H values of 33 ± 4 km (inversion of TEPHRA2 model on grain size data) corresponding to mass discharge ranging from 2.3 to 6.0 × 10 kg/s. Lake-core data allow extrapolation of the deposit thinning trend far beyond onland exposures. Empirical fitting of thickness data yields volume estimates between 3.2 and 5.8 km (corresponding to an erupted mass of 1.1-2.0 × 10 kg), whereas analytical derivation yields an erupted mass of 1.1 × 10 kg (inversion of TEPHRA2 model). Modelling and dispersal maps are consistent with nearly no-wind conditions during the eruption. The plume corner is estimated to have been ca. 11-12 km from the vent. After an opening phase with gradually increasing intensity, a high discharge rate was maintained throughout the eruption, without fountain collapse as is evidenced by a lack of pyroclastic density current deposits. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
5. Fundamental changes in the activity of the natrocarbonatite volcano Oldoinyo Lengai, Tanzania.
- Author
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Kervyn, Matthieu, Ernst, Gerald G. J., Keller, Jörg, Vaughan, R. Greg, Klaudius, Jurgis, Pradal, Evelyne, Belton, Frederic, Mattsson, Hannes B., Mbede, Evelyne, and Jacobs, Patric
- Subjects
VOLCANIC eruptions ,EARTHQUAKE swarms ,VOLCANISM - Abstract
On September 4, 2007, after 25 years of effusive natrocarbonatite eruptions, the eruptive activity of Oldoinyo Lengai (OL), N Tanzania, changed abruptly to episodic explosive eruptions. This transition was preceded by a voluminous lava eruption in March 2006, a year of quiescence, resumption of natrocarbonatite eruptions in June 2007, and a volcano-tectonic earthquake swarm in July 2007. Despite the lack of ground-based monitoring, the evolution in OL eruption dynamics is documented based on the available field observations, ASTER and MODIS satellite images, and almost-daily photos provided by local pilots. Satellite data enabled identification of a phase of voluminous lava effusion in the 2 weeks prior to the onset of explosive eruptions. After the onset, the activity varied from 100 m high ash jets to 2-15 km high violent, steady or unsteady, eruption columns dispersing ash to 100 km distance. The explosive eruptions built up a ∼400 m wide, ∼75 m high intra-crater pyroclastic cone. Time series data for eruption column height show distinct peaks at the end of September 2007 and February 2008, the latter being associated with the first pyroclastic flows to be documented at OL. Chemical analyses of the erupted products, presented in a companion paper (Keller et al. ), show that the 2007-2008 explosive eruptions are associated with an undersaturated carbonated silicate melt. This new phase of explosive eruptions provides constraints on the factors causing the transition from natrocarbonatite effusive eruptions to explosive eruptions of carbonated nephelinite magma, observed repetitively in the last 100 years at OL. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
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