37 research outputs found
Stochastic characterization of geological heterogeneity and its impact on groundwater contaminant transport
No full textAbstract not availableCivil Engineering and Geoscience
Reducing geological uncertainty by conditioning on boreholes: The coupled Markov chain approach
No full textCivil Engineering and Geoscience
Fatigue and shear failure. Differences between NEN and Eurocode.
No full textWithin this document the differences arising from the transition of the NEN (Dutch code) to the Eurocode are studied with respect to shear failure and fatigue. These differences are investigated on a global level, where in addition the fib Model Code is taken into account. In the next part the actual differences are determined within a case study, consisting of a viaduct for road traffic build up from precast girders. Finally, conclusions and recommendations are given.Concrete StructuresStructural EngineeringCivil Engineering and Geoscience
The effectiveness of deep brain stimulation in improving upper and lower extremity function under dual task conditions in Parkinson?’s disease patients
No full textParkinson?’s disease (PD) is a progressive neurodegenerative disorder characterized by reduced movement. Postural instability and gait dysfunction (PIGD) is one of the more debilitating symptoms of PD due to its effect on activities of daily life and increased risk for falls. In later stages of the disease, cognitive impairment affects executive functioning and working memory. Although, most activities in daily living require both motor and cognitive functioning like cycling (motor) while holding a conversation (cognitive). Bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown to reduce motor deficits in advanced Parkinson?’s disease patients. However, the effectiveness of STN DBS on postural instability is less pronounced. It has been shown that bilateral STN DBS results in cognitive declines under dual-??task conditions using an upper extremity task and these declines compromise motor function. The aim of this study was to asses the effectiveness of STN DBS on cognitive-??motor performance during a lower extremity task. 15 advanced PD patients, of which seven presented PIGD symptoms, were tested under single-?? and dual-??task conditions. All patients were bilaterally implanted with STN DBS and had stable parameters as determined through typical clinical programming for at least 6 moths prior to study enrollment. Patients were assessed off anti-??parkinsonian medication under two DBS settings; Off DBS and On DBS. In each condition, patients performed a working memory task (n-??back) and a postural stability task (quiet standing). During the dual task, patients performed the working memory and postural stability tasks simultaneously. DBS was effective in improving Unified Parkinson?’s disease Rating Scale III scores relative to no stimulation. Cognitive functioning showed no difference between the two DBS conditions. Patients with PIGD symptoms were significantly less stable than patients with no PIGD symptoms for both On and Off DBS conditions. These data show that with the paradigm used in this study, PIGD symptoms continue to be refractory to DBS. Postural stability as assessed by quietly standing on a force platform may not have been challenging enough to evoke cognitive declines.BMEBioMechanical EngineeringMechanical, Maritime and Materials Engineerin
Challenges and opportunities in migrating to web-based information services: perspective of web-based enterprise
No full textVastly growing Web-technology has matured enough to become an
attractive platform for business applications and organizational
information systems. Large and small organizations are increasing their
investment in Web-based Information Systems (IS) resources, such as
Electronic Commerce, Intranets and Extranets. The Web technology is
often presented as a 'revolution' in information system technologies in
the business press which could propel change from static, hierarchical
structures to more dynamic, flexible and 'knowledge-based'
organizational forms. To the companies, more and more legacy
information and database systems are being migrated to Web-based
environments. This research aims at analyzing and advising enterprises
to be Web-based enterprise with challenges and opportunities. During
the research, researcher investigated a company that were using the
Web-based (applications made available via the World Wide Web)
information service. Various research methods were adopted by the
author. Data were collected through lecture review and in-depth
interviews. Undoubtedly, there are some troubles existed in migrating,
such as technologies for restructure information system structure,
resource distribution, benefit analysis, planning and management,
operation and maintenance etc. But still obviously, as the research
shows that there are many benefits can be got follows the
implementation of Web-based solution
Sustainability indicators in university campuses: The experience of Universidade de São Paulo, Brazil
No full textThis article aims at describing the performance of sustainability indicators for Universidade de São Paulo, developed in Agência USP de Inovação/USP Recicla Program. In this context, the university's resources consumption has been assessed and indicators have been established so as to support actions, goals and sustainability policies for the institution. Generally, indicators are attributes that facilitate the understanding of a situation, by indicating - as possible - the current situation and comparing it with the desired situation. A survey performed in 2009 considered two steps: i) introduction and analysis of certain consumption indicators in 7 USP campuses, such as disposable glasses, water, electric power, built-up areas and vegetal covering, transportation and generation of waste; ii) partial data conversion into "ecological footprint". The data presented and discussed herein were raised with each campus, including colleges, schools and teaching and research institutes; in specific purchase and material distribution, water and power consumption and engineering sectors and green areas inside USP. The results achieved indicated that each member of the university community demands approximately 160m²/year of forest to absorb the impacts caused by resources consumption and waste production. The main environmental impacts noticed are related to power consumption (66%), buildings (17%) and paper consumption (13%). By considering the several challenges we faced the lack of an articulated data measurement and a control system at USP
Spectral MST-Based Graph Outlier Detection With Application to Clustering of Power Networks
No full textAn increasing number of methods for control and analysis of power systems relies on representing power networks as weighted undirected graphs. Unfortunately, the presence of outliers in power system graphs may have a negative impact on many of these methods. In addition, detecting outliers can be a relevant task on its own. Motivated by the low number of outlier detection algorithms focusing on weighted undirected graphs, this paper proposes an efficient and effective method to detect loosely connected graph clusters below a certain number of nodes. The essence of the method lies in the efficient examination of the spectral minimal spanning tree of the input graph. The obtained results on several large test power networks validate the high outlier detection performance of the proposed method and its high computational efficiency.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.Intelligent Electrical Power Grid
Influence of temporal fluctuations and spatial heterogeneity on pollution transport in porous media
No full textThe combined influence of temporal fluctuations and spatial heterogeneity on non-reactive solute transport mechanisms in porous media can be understood by performing simulations of steady and unsteady flow and transport in heterogeneous media. The study focuses on issues such as the degree of heterogeneity, correlation length, separation of the combined effects of temporal and spatial variations, and ergodicity conditions under unsteady flow conditions. It is shown that the effect of temporal variations on solute transport is masked by the strong effect of spatial heterogeneity. There is no obvious difference in plume shape between steady and unsteady flow conditions; the first and the second spatial moments of the plume of the unsteadystate flow condition fluctuate around the steady-state flow condition with the same period of oscillations as the input signal at small storage coefficient (S?0.001). At a relatively high standard deviation in hydraulic conductivity and a small storage coefficient, the unsteady flow condition sharpens the temporal variations in macrodispersion coefficients. The magnitude of the longitudinal macrodispersion coefficient under unsteady flow condition is almost doubled at the maximum values. However, the transverse macrodispersion coefficient fluctuates around zero. The Kubo number and Peclet number ranges are 1.2–64 and 10–250, respectively.Geoscience & EngineeringCivil Engineering and Geoscience
Agricultural and non-agricultural outputs and energy consumption in Tunisia: empirical evidences from cointegration and causality
No full textThis short paper investigates the cointegration and causality link between energy consumption and agricultural, non-agricultural outputs (manufacturing sector and services sector) and overall gross domestic product in Tunisia for 1971-2003 period. Empirical results suggest that there is only unidirectional causality running from agricultural and non-agricultural sectors to energy consumption as well as from overall GDP growth to energy consumption. This unidirectional causality signifies a less energy dependent economy and suggests that it is sectoral growth that drives the energy consumption in Tunisia and not vice versa. Empirical results suggest also that Tunisian agricultural sector growth does not depend on energy, and high consumption of energy do not implies more productivity in the short run for this sector.energy consumption, output growth, causality, cointegration, Tunisia, Resource /Energy Economics and Policy,
