327 research outputs found

    How Can Mobile Applications Reduce Energy Consumption? An Experimental Investigation of Electric Vehicles

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    The role of information systems for environmental sustainability has received considerable attention over the last several years. In view of global warming and climate change, a transition from combustion to electric vehicles (EVs) can help reduce greenhouse gas (GHG) emissions. Since sustainable behavior often lacks relevant information about its environmental effects, the role of information systems in influencing energy consumption is being explored in this paper. The main focus is to investigate the impact of driver assistance systems in form of mobile applications on the energy consumption of EVs. To test such an impact, a field experiment is conducted by defining a control group and an experimental group. Test drives are performed with an all-electric, lithium-ion battery powered, small passenger city car. As the treatment of the study, a mobile application is chosen that monitors excessive acceleration and hard braking. The results reveal significant differences among the groups, which indicate that using smartphone-based driver assistance systems significantly reduces the energy consumption of EVs. This can entail several benefits, including an increase of range of EVs, electricity cost savings, decrease of vehicle wear, and reduction of GHG emissions. The findings are discussed and implications for research and practice are given

    Finite Element Simulations of Two-phase Flow and Floating Bodies Using FEniCS-HPC

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    We present a variational multiscale stabilized finite element method to solve the variable density incompressible Navier-Stokes equations for the simulation of two-phase flow. We introduce a level-set method based on the compression technique similar to [1]. For the simulation of floating devices we make use of a simplified rigid body motion scheme and a deforming mesh approach [2]. The mesh deforms elastically following the movement of the body. An implicit turbulence model is used where turbulence is modelled by the numerical stabilization. The described methods are implemented in the open source software framework FEniCS-HPC [3] provided with an automated methodology for discretization and error control. We are working in a project for marine energy generation together with Tecnalia R&I. In this context we simulate floating platforms that will be used for marine energy generation or device experimentation in the ocean. The aim is to study the dynamics of this kind of off-shore devices. Our simulation results are compared against the experimental data obtained by Tecnalia R&I company in the experimental tank of CEHIPAR in Spain. We also participate in the IEA-OES Task 10 project where different simulations of floating bodies are carried out. The results are compared against other groups simulations that use different methodologies

    Nonlinear computations of heave motions for a generic Wave Energy Converter

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    A bench-marking activity of numerical methods for analysis of Wave Energy Converters (WEC) was proposed under the Ocean Energy Systems (OES) International Energy Agency (IEA) Task 10 in 2015. The purpose of the benchmark is to do a code-2-code comparison of the predicted motions and power take out for a WEC. A heaving sphere was used as a first simple test case. The participants sim- ulated heave decay and regular and irregular wave cases. The numerical methods ranged from linear methods to viscous methods solving the Navier-Stokes equa- tions (CFD). An overview of the results from the first phase of the benchmark was reported in [1]. The present paper focus on the simulations of the sphere using one fully nonlinear time-domain BEM one transient RANS method and one transient Direct FE method with no turbulence model. The theory of the three methods as well as the modeling of the sphere are described. Heave decay and heave motions for steep regular waves were selected as test cases in order to study and compare the capability to handle nonlinear effects. Computational efficiency and applicability of the three methods are also discussed

    The effect of racemic gossypol and AT-101 on angiogenic profile of OVCAR-3 cells: a preliminary molecular framework for gossypol enantiomers

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    To compare the effect of racemic gossypol with its (–)/(–) enantiomer (AT-101) on expression profiles of angiogenic molecules by mRNA levels in human ovarian cancer cell line OVCAR-3. Methods: Cell viability assay (2,3-bis (2-methoxy-4-nitro-5- sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) was used to detect cytotoxicity of gossypol enantiomers. DNA fragmentation by an enzyme-linked immunosorbent (ELISA) assay was used to evaluate the rate of apoptosis. The mRNA expression levels of angiogenic molecules were investigated by Human Angiogenesis RT2 ProfilerTM PCR Array (SuperArray, Frederick, MD). Results: Both racemic form and AT-101 resulted in a significant cytotoxicity and induced apoptosis. This effect was observed in a dose- and time dependent manner. However, AT-101 was much more potent. In addition, the treatment of 10 μM of racemic gossypol alone and 3 μM of AT-101 alone resulted in significant down-regulation (≥ 3 fold) in mRNA levels of some pivotal angiogenic molecules in OVCAR-3, but altered gene profiles were different by the treatment of each enantiomer. Conclusion: The efficacy of two gossypol enantiomers in OVCAR-3 cells showed distinction. AT-101 was much more potent than racemic gossypol, not only by means of cell death and apoptosis, but also by modulation of angiogenic molecules released from OVCAR-3 cells. Further studies with endothelial cells should be done to verify the anti-angiogenic effect of gossypol enantiomers in cancer treatment

    Operando potassium K-edge X-ray absorption spectroscopy: investigating potassium catalysts during soot oxidation.

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    The chemical and structural nature of potassium compounds involved in catalytic soot oxidation have been studied by a combination of temperature programmed oxidation and operando potassium K-edge X-ray absorption spectroscopy experiments. These experiments are the first known operando studies using tender X-rays (∼3.6 keV) under high temperature oxidation reaction conditions. X-ray absorption near edge structure analysis of K2CO3/Al2O3 catalysts during heating shows that, at temperatures between 100 and 200 °C, potassium species undergo a structural change from an initial hydrated K2CO3·xH2O and KHCO3 mixture to well-defined K2CO3. As the catalyst is heated from 200 °C to 600 °C, a feature associated with multiple scattering shifts to lower energy, indicating increased K2CO3 dispersion, due to its mobility at high reaction temperature. This shift was noted to be greater in samples containing soot than in control experiments without soot and can be attributed to enhanced mobility of the K2CO3, due to the interaction between soot and potassium species. No potassium species except K2CO3 could be defined during reactions, which excludes a potential reaction mechanism in which carbonate ions are the active soot-oxidising species. Simulations of K-edge absorption near edge structures were performed to rationalise the observed changes seen. Findings showed that cluster size, unit cell distortions and variation in the distribution of potassium crystallographic sites influenced the simulated spectra of K2CO3. While further simulation studies are required for a more complete understanding, the current results support the hypothesis that changes in the local structure on dispersion can influence the observed spectra. Ex situ characterisation was carried out on the fresh and used catalyst, by X-ray diffraction and X-ray photoelectron spectroscopy, which indicated changes to the carbonate species, in line with the X-ray absorption spectroscopy experiments

    Concern for information privacy:a cross-nation study of the United Kingdom and South Africa

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    Individuals have differing levels of information privacy concern, formed by their expectations and the confidence they have that organisations meet this in practice. Variance in privacy laws and national factors may also play a role. This study analyses individuals’ information privacy expectation and confidence across two nations, the United Kingdom and South Africa, through a survey of 1463 respondents. The findings indicate that the expectation for privacy in both countries are very high. However, numerous significant differences exist between expectations and confidence when examining privacy principles. The overall results for both countries show that there is a gap in terms of the privacy expectations of respondents compared to the confidence they have in whether organisations are meeting their expectations. Governments, regulators, and organisations with an online presence need to consider individuals’ expectations and ensure that controls that meet regulatory requirements, as well as expectations, are in place

    Complex regional pain syndrome type I: efficacy of stellate ganglion blockade

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    PubMed ID: 19888550Background: This study was performed to evaluate the treatment of complex regional pain syndrome (CRPS) type I with stellate ganglion blockade. Materials and methods: We performed three blockades at weekly intervals in 22 patients with CRPS type I in one hand. The patients were divided into two groups depending on the time between symptom onset and treatment initiation. Group 1and 2 patients had short and long symptom-onset-to-treatment intervals, respectively. Pain intensity, using a visual analog score (VAS), and range of motion (ROM) for the wrist joint were assessed before and 2 weeks after treatment and were compared using nonparametric statistical analysis. Results: Treatment produced a statistically significant difference in wrist ROM for all patients (P < 0.001). VAS values showed an overall decrease from 8 ± 1 to 1 ± 1 following treatment, and there was a significant difference in VAS value between groups 1 and 2 (P < 0.05). Conclusions: We concluded that stellate ganglion blockade successfully decreased VAS and increased ROM of wrist joints in patients with CRPS type I. Further, the duration between symptom onset and therapy initiation was a major factor affecting blockade success. © 2009 Springer-Verlag
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