1,237 research outputs found

    Displacement Ductility Capacity of Fixed-Head Piles

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    This study performs a parametric study on the displacement ductility capacity of a fixed-head pile. The Winkler-beam model is employed, in which both the soil nonlinearity and pile nonlinearity are adequately considered. In this parametric study, the pile is regarded as a limited ductility structure which conditionally allows the pile deformation to enter the plastic range during loadings. The analysis variables include the axial force, the pile diameter, the longitudinal reinforcement ratio, and the soil stiffness. The relationships of the displacement ductility capacity of the pile to the curvature ductility capacity and to the over-strength ratio of the pile section are examined through a large number of pushover analyses. Results show that the axial force level, the pile diameter, and the steel ratio remarkably influence the displacement ductility capacity of a fixed-head pile. Their influence can be represented mainly by the over-strength ratio of the pile section. Besides, the influence of the soil stiffness is insignificant: the displacement ductility capacity slightly decreases with the soil stiffness

    THE VERTICAL INTEGRATION OF CONTENT AND BROADBAND SERVICES: THE NET NEUTRALITY DEBATE

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    Whether broadband service providers should be allowed to vertically integrate with content providers is a contentious issue, especially from the net neutrality perspective, since the vertically integrated firm can prioritize the delivery of its own content at the expense of that of its competitors if net neutrality is not enforced. We analyze the issues of vertical integration of content and broadband services surrounding this debate from an economic perspective, using a game-theoretic model. Our analysis establishes the various equilibria in the game, and shows that if net neutrality is not enforced, social welfare might – depending on parameter values – increase or decrease with vertical integration. Interestingly, we find that it is not always true that the ISP will always degrade the delivery of the competing content, and in fact will sometimes have the incentive to prioritize the latter over its own

    Stability analysis and dynamic equilibrium of a Kuroshio generator system

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    Global resources for conventional energy are currently being exhausted, and several countries worldwide are attempting to develop renewable energy. Current generator systems are a subject of ocean power research. This paper proposes a novel design of a Kuroshio generator system (KGS) that is suitable for the maritime environment of Taiwan (i.e., an average flow velocity of the Kuroshio Current is 1.45 m/s and the flow can be accelerated on Keelung Sill with a depth of 50-250 m). The KGS combined a reliable cable design and simple anchor system at sea and was not affected by motion changes of rotation axes in yaw and roll by way of an appropriate rudder design. An intuitive simulation method applied using MapleSim software was used to create a rigid KGS model. Different modeling frameworks for varied cable design and joint positions were adjusted to meet system requirements. An intuitive simulation method applied using MapleSim software was used to create a rigid KGS model. Different modeling frameworks for varied cable design and joint positions were adjusted to meet system requirements. The stability analysis was performed to determine dynamic equilibrium and motion behavior of the KGS and the combined cable design. The optimal spring stiffness and damper coefficient of polyester fibers were set as 5×105 N/m and 3×105 N∙s/m in the simulation, respectively. Furthermore, to achieve the torque equilibrium in pitch motion of the KGS, an optimal joint position that was relative to the leading infraedge of the outer duct was set at 2.2 m along the negative surge axis according to their responses in the simulation. Finally, the force and torque generated by the hydrodynamic effect in the KGS and the estimated specifications of a direct-drive permanent magnet generator equipped with an external rotor were imported into the simulation. Consequently, the motion ranges of translation axes in surge and heave were converged within 0.5 m, and the estimated output power in the KGS exceeded 54.8 kW

    Seismic Fragility Analysis for Sheet Pile Wharves — Case Study of the Hualien Harbor in Taiwan

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    The seismic fragility curves represent the conditional probabilities that the structural damage meets or exceeds the specified damage states at various levels of the ground motion parameters, such as peak ground acceleration (PGA). In this study, the seismic fragility analysis for the sheet pile wharves of the Hualien Harbor in Taiwan was performed. The finite element analysis software PLAXIS was adopted for the nonlinear dynamic analysis. The time histories of several representative earthquake events that actually occurred in Taiwan, including the 1999 Chi-Chi Earthquake, were scaled to various PGA levels as the input motions. Then the seismic responses of the sheet pile wharves subjected to these earthquakes of different intensities were obtained. It is assumed that the maximum residual displacement at the top of the sheet pile wall is lognormal distributed. Thus, the conditional exceedance probabilities of each specified damage state at different levels of PGA were estimated according to the displacement threshold value of each damage state, and the fragility curves were deduced. Moreover, these fragility curves were parameterized assuming they can be well approximated by the lognormal cumulative probability function, which is important for the rapid estimation of earthquake loss

    Retraction and Generalized Extension of Computing with Words

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    Fuzzy automata, whose input alphabet is a set of numbers or symbols, are a formal model of computing with values. Motivated by Zadeh's paradigm of computing with words rather than numbers, Ying proposed a kind of fuzzy automata, whose input alphabet consists of all fuzzy subsets of a set of symbols, as a formal model of computing with all words. In this paper, we introduce a somewhat general formal model of computing with (some special) words. The new features of the model are that the input alphabet only comprises some (not necessarily all) fuzzy subsets of a set of symbols and the fuzzy transition function can be specified arbitrarily. By employing the methodology of fuzzy control, we establish a retraction principle from computing with words to computing with values for handling crisp inputs and a generalized extension principle from computing with words to computing with all words for handling fuzzy inputs. These principles show that computing with values and computing with all words can be respectively implemented by computing with words. Some algebraic properties of retractions and generalized extensions are addressed as well.Comment: 13 double column pages; 3 figures; to be published in the IEEE Transactions on Fuzzy System

    Safety assessment of poly-ε-caprolactone in the treatment of primary spontaneous pneumothorax

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    Background/purposeBiomaterial-based implants are gaining traction as an option for pleurodesis treatment, yet the search for the best biomaterial or the most suitable shape to handle spontaneous pneumothorax continues. This forward-looking research assessed the use of a poly-ε-caprolactone membrane for its safety when applied as a sclerosant in pleurodesis procedures in human patients.MethodsFrom July 2017 to February 2018, we conducted a Phase I trial in which 10 patients with primary spontaneous pneumothorax were treated using video-assisted thoracoscopic surgery with a poly-ε-caprolactone membrane. These procedures encompassed bleb resection and mechanical pleurodesis through parietal pleura scrubbing. After resection, a 150 × 150 mm poly-ε-caprolactone membrane was applied to the apex. The primary outcome measures were the adverse events and laboratory outcomes.ResultsAfter surgery, we observed no cardiopulmonary-related adverse events or indications of systemic inflammation. Furthermore, no episodes of hypothermia or hyperthermia occurred. Chest radiographs showed no evident pneumonitis or effusion associated with tissue reactions. The average follow-up duration was 31.7 ± 17.7 months, during which two patients exhibited recurrence.ConclusionThis study is the first to show the biocompatibility of poly-ε-caprolactone in humans, suggesting its potential as a treatment option for patients with primary spontaneous pneumothorax. Despite the relatively small number of patients, we maintain confidence in the reliability and safety profile of the PCL membrane, bolstered by its previously established efficacy in applications involving other organs. Phase II and phase III clinical studies are needed to support these observations

    Effects of Hydrogen on the Optical and Electrical Characteristics of the Sputter-Deposited Al2O3-Doped ZnO Thin Films

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    In this study, AZO thin films were deposited on glass by using a 98 mol% ZnO + 1 mol% Al2O3 (AZO, Zn : Al = 98 : 2) ceramic target and a r.f. magnetron sputtering system. At first, the effects of different H2 flow rates (H2/(H2 + Ar) = 0%~9.09%, abbreviated as H2-deposited AZO thin films, deposition temperature was 200°C) added during the deposition process on the physical and electrical properties of AZO thin films were investigated. The optical transmittance at 400 nm~700 nm is more than 80% for all AZO thin films regardless of H2 flow rate and the transparency ratio decreased as the H2 flow rate increased. The Burstein-Moss shift effect was used to prove that the defects of AZO thin films decreased with increasing H2 flow rate. Also, the 2% H2-deposited AZO thin films were also treated by the H2 plasma at room temperature for 60 min (plasma-treated AZO thin films). The value variations in the optical band gap (Eg) values of the H2-deposited and plasma-treated AZO thin films were evaluated from the plots of αhν2=c(hν−Eg), and the Eg values increased with increasing H2 flow rate. The Eg values also increased as the H2-plasma process was used to treat on the H2-deposited Al2O3-doped ZnO (AZO) thin films

    Modulating Microglia/Macrophage Activation by CDNF Promotes Transplantation of Fetal Ventral Mesencephalic Graft Survival and Function in a Hemiparkinsonian Rat Model

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    Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in substantia nigra pars compacta, which leads to the motor control deficits. Recently, cell transplantation is a cutting-edge technique for the therapy of PD. Nevertheless, one key bottleneck to realizing such potential is allogenic immune reaction of tissue grafts by recipients. Cerebral dopamine neurotrophic factor (CDNF) was shown to possess immune-modulatory properties that benefit neurodegenerative diseases. We hypothesized that co-administration of CDNF with fetal ventral mesencephalic (VM) tissue can improve the success of VM replacement therapies by attenuating immune responses. Hemiparkinsonian rats were generated by injecting 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle of Sprague Dawley (SD) rats. The rats were then intrastriatally transplanted with VM tissue from rats, with/without CDNF administration. Recovery of dopaminergic function and survival of the grafts were evaluated using the apomorphine-induced rotation test and smallanimal positron emission tomography (PET) coupled with [F-18] DOPA or [F-18] FE-PE2I, respectively. In addition, transplantation-related inflammatory response was determined by uptake of [F-18] FEPPA in the grafted side of striatum. Immunohistochemistry (IHC) examination was used to determine the survival of the grated dopaminergic neurons in the striatum and to investigate immune-modulatory effects of CDNF. The modulation of inflammatory responses caused by CDNF might involve enhancing M2 subset polarization and increasing fractal dimensions of 6-OHDA-treated BV2 microglial cell line. Analysis of CDNF-induced changes to gene expressions of 6-OHDA-stimulated BV2 cells implies that these alternations of the biomarkers and microglial morphology are implicated in the upregulation of protein kinase B signaling as well as regulation of catalytic, transferase, and protein serine/threonine kinase activity. The effects of CDNF on 6-OHDA-induced alternation of the canonical pathway in BV2 microglial cells is highly associated with PI3K-mediated phagosome formation. Our results are the first to show that CDNF administration enhances the survival of the grafted dopaminergic neurons and improves functional recovery in PD animal model. Modulation of the polarization, morphological characteristics, and transcriptional profiles of 6-OHDA-stimualted microglia by CDNF may possess these properties in transplantation-based regenerative therapies.Peer reviewe
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