897 research outputs found

    Quantitative imaging of gas adsorption equilibrium and dynamics by X-ray Computed Tomography

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    We present the development and application of X-ray Computed Tomography (CT) for the determination of the adsorption properties of microporous adsorbents and the study of breakthrough experiments in a laboratory fixed-bed adsorption column. Using the model system CO2/helium on activated carbon, equilibrium and dynamic adsorption/desorption measurements by X-ray CT are described, and the results are successfully compared to those obtained from conventional methods, including the application of a one-dimensional dynamic column breakthrough model. The study demonstrates the practical feasibility of applying X-ray CT to measure internal and transient concentration profiles in adsorbent systems on the length-scales from a single adsorbent pellet to a packed column

    Development of constitutive model for precast prestressed concrete segmental columns

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    The interest of using precast segmental columns in construction of concrete bridges has significantly increased in recent years. One research area of concrete bridges is the application of Precast Prestressed Concrete Segmental (PPCS) Column in any structural analysis software or FE program code. Modeling a PPCS column, which consists of various materials with interaction between them, is complicated and time-consuming. This research attempts to formulate the stiffness matrix of PPCS columns in order to form the constitutive model in linear form to evaluate the response of the columns. A two-dimensional finite element model is presented in the finite element package ANSYS. Parametric studies are conducted by finite element models to verify the constitutive models for the PPCS column with a different number of concrete segments. Comparison between the constitutive model and the FE program results indicates that the constitutive model is accurate enough to predict the deformation of the PPCS columns

    Laboratory Evaluation of Five Chitin Synthesis Inhibitors Against the Colorado Potato Beetle, Leptinotarsa decemlineata

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    Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. The mortalities and abnormalities of the treated larvae were recorded 72 hours after treatments. LC50 values were 58.6, 69.6, 27.3, 0.79 and 81.4 mg ai/ L for diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, respectively. Compared with phosalone, which is one of the common insecticides used for controlling this pest in Iran, lufenuron and hexaflumuron seem to be much more potent, and if they perform equally well in the field, they would be suitable candidates to be considered as reduced risk insecticides in management programs for L. decemlineata due to much wider margin of safety for mammals and considerably fewer undesirable environmental side effects

    Benefits of greenhouse gas mitigation on the supply, management, and use of water resources in the United States

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    Climate change impacts on water resources in the United States are likely to be far-reaching and substantial because the water is integral to climate, and the water sector spans many parts of the economy. This paper estimates impacts and damages from five water resource-related models addressing runoff, drought risk, economics of water supply/demand, water stress, and flooding damages. The models differ in the water system assessed, spatial scale, and unit of assessment, but together provide a quantitative and descriptive richness in characterizing water sector effects that no single model can capture. The results, driven by a consistent set of greenhouse gas (GHG) emission and climate scenarios, examine uncertainty from emissions, climate sensitivity, and climate model selection. While calculating the net impact of climate change on the water sector as a whole may be impractical, broad conclusions can be drawn regarding patterns of change and benefits of GHG mitigation. Four key findings emerge: 1) GHG mitigation substantially reduces hydro-climatic impacts on the water sector; 2) GHG mitigation provides substantial national economic benefits in water resources related sectors; 3) the models show a strong signal of wetting for the Eastern US and a strong signal of drying in the Southwest; and 4) unmanaged hydrologic systems impacts show strong correlation with the change in magnitude and direction of precipitation and temperature from climate models, but managed water resource systems and regional economic systems show lower correlation with changes in climate variables due to non-linearities created by water infrastructure and the socio-economic changes in non-climate driven water demand

    Touchstone Stars: Highlights from the Cool Stars 18 Splinter Session

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    We present a summary of the splinter session on "touchstone stars" -- stars with directly measured parameters -- that was organized as part of the Cool Stars 18 conference. We discuss several methods to precisely determine cool star properties such as masses and radii from eclipsing binaries, and radii and effective temperatures from interferometry. We highlight recent results in identifying and measuring parameters for touchstone stars, and ongoing efforts to use touchstone stars to determine parameters for other stars. We conclude by comparing the results of touchstone stars with cool star models, noting some unusual patterns in the differences.Comment: Proceedings of the 18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Eds G. van Belle & H. Harri

    The Unseen Face of E-Business Project Development

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    The purpose of this paper is intent on identify and analyze the unseen factors of successful or failure of e-business project development. The IT managers must take into account both all costs involved in e-business development and all phases (analysis, design, testing, implementation, maintenance and operation) according to principle of project management for software/systems life cycle development. There are many solutions to exceed these factors of failure among could be counted outsourcing, a good project management, involvement of senior management, a real cost estimation etc.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej nauk

    A HIERARCHICAL APPROACH TO ROTATION-INVARIANT TEXTURE FEATURE EXTRACTION BASED ON RADON TRANSFORM PARAMETERS

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    ABSTRACT In this paper, we propose an efficient hierarchical method for extracting invariant texture features using the Gabor wavelets and Radon transform parameters. The proposed method applies the Radon transform to estimate the directional information in the highband texture image extracted by Gabor wavelets. The directional information is then used to make the texture feature invariant to rotation. To show the efficiency of our scheme, we developed a texture-based image retrieval system based on the proposed method and evaluated it on a set of images from the Brodatz album. Experimental results show that the proposed system outperforms previous rotation-invariant systems significantly

    Effect of yoga on depression and anxiety of women”,

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    a b s t r a c t Yoga has often been perceived as a method of stress management tool that can assist in alleviating depression and anxiety disorders. This study sought to evaluate the influence of yoga in relieving symptoms of depression and anxiety in women who were referred to a yoga clinic. Methods: The study involved a convenience sample of women who were referred to a yoga clinic from July 2006 to July 2007. All new cases were evaluated on admission using a personal information questionnaire well as Beck and Spielberger tests. Participants were randomly assigned into an experimental and a control group. The experimental group (n ¼ 34) participated in twice weekly yoga classes of 90 min duration for two months. The control group (n ¼ 31) was assigned to a waiting list and did not receive yoga. Both groups were evaluated again after the two-month study period. Results: The average prevalence of depression in the experimental group pre and post Yoga intervention was 12.82 AE 7.9 and 10.79 AE 6.04 respectively, a statistically insignificant decrease (p ¼ 0.13). However, when the experimental group was compared to the control group, women who participated in yoga classes showed a significant decrease in state anxiety (p ¼ 0.03) and trait anxiety (p < 0.001). Conclusions: Participation in a two-month yoga class can lead to significant reduction in perceived levels of anxiety in women who suffer from anxiety disorders. This study suggests that yoga can be considered as a complementary therapy or an alternative method for medical therapy in the treatment of anxiety disorders
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