309 research outputs found

    Novel iBeacon Placement for Indoor Positioning in IoT

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    © 2018 IEEE. Indoor positioning and location estimation inside the buildings is still challenging in the Internet of Things platform. However, the GPS signals could successfully solve the outdoor localization problem. A recently introduced RSS-based device, named iBeacon, paves the way to estimate the users location inside the buildings. Due to the complexity of indoor RF environments, the positioning accuracy is affected by the placement of the iBeacons. Inadvertently, the concept of iBeacon placement for improving the accuracy remains unattended by the current research. This paper provides a comprehensive analysis and experiments on the importance of iBeacon placement, and factors impacting the beacon signal quality. Moreover, we propose a novel beacon placement strategy, Crystal-shape iBeacon Placement. As another contribution, a customized application for android is developed which is used for recording and analyzing the iBeacon signals. Our proposed placement strategy could achieve 21.7% higher precision than the existing normal iBeacon placement

    Effects of Lateral Wedge Insole on Static and Dynamic Balance in Patients with Moderate Medial Knee Osteoarthritis

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    BACKGROUND AND OBJECTIVE: Knee osteoarthritis (OA) is associated with diminished joint proprioception, balance deficits and increased risk of falls. Patients with medial knee osteoarthritis are at higher risk of balance deficits and falling due to the development of secondary varus deformity. Therefore, it is of great clinical importance to identify the treatment methods that could improve balance in knee OA. The purpose of this study was to evaluate the effects of Lateral Wedge Insole (LWI) on static and dynamic balance in patients with moderate medial knee osteoarthritis. METHODS: Thirty patients with moderate medial knee OA participated in this semi-experimental interventional study. Patients were recruited from orthopedic and rheumatology clinics of the university. For each patient, the static and dynamic balance were assessed in two conditions including wearing shoes with flat insole and wearing shoes with lateral wedge insole, using a Prokin stabilometer. The balance variables were the anteroposterior and mediolateral velocity and standard deviation of the center of pressure (COP) displacement, and total stability indices. Patients performed two familiarization trials, then, three actual trials with at least 30 s interval for each test. FINDINGS: Wearing LWIs resulted in significant decreases in the anteroposterior (static:1.78mm/s, dynamic:6.63mm/s) and mediolateral velocity of COP (static:1.53mm/s, dynamic:5.58mm/s) in compression to wearing shoes with flat insole (p<0.001). The anteroposterior (static:1.04 mm, dynamic:1.57mm) and mediolateral SD of the COP (static:1.58mm, dynamic:2.02mm) were also decreased after using LWIs (p<0.007). Except for the anteroposterior stability index, other balance indices were also significantly improved (p<0.05). CONCLUSION: Our findings suggest that using a LWI improve static and dynamic balance in patients with moderate medial knee OA

    Energy Performance of Advanced Reboiled and Flash Stripper Configurations for CO2 Capture Using Monoethanolamine

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    CO2 capture by absorption using amine solvents has the potential to significantly reduce the CO2 emissions from fossil-fuel power plants. One of the major costs of this technology is the energy required for solvent regeneration. Complex process configurations claim to have promising potential to reduce the energy required for solvent regeneration. In this work, the effect of flow-sheet complexity is explored by studying two advanced stripping flow sheets: an advanced flash stripper and an advanced reboiled stripper. Both advanced configurations recover the stripping steam heat by means of a heat integration comprised of cold- and warm-rich solvent bypasses. The advanced configurations are simulated and optimized in Aspen Plus V.8.4 using 7 m monoethanolamine (MEA) with lean loading from 0.15 to 0.38 (mol CO2/mol MEA). The rich loading associated with each lean loading is determined by simulating the absorber providing 90% capture from flue gas with 4 mol % CO2, typical of a natural gas-fired turbine. The results are compared to a simple stripper in terms of total equivalent work. Both the advanced reboiled stripper and the advanced flash stripper require 12% less equivalent work than a simple stripper. The associated cold-rich and warm-rich bypasses for the optimum cases are, respectively, 20% and 50% for the advanced reboiled stripper and 15% and 35% for the advanced flash stripper

    Level Crossing Analysis of Burgers Equation in 1+1 Dimensions

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    We investigate the average frequency of positive slope να+\nu_{\alpha}^{+}, crossing the velocity field u(x)uˉ=αu(x)- \bar u = \alpha in the Burgers equation. The level crossing analysis in the inviscid limit and total number of positive crossing of velocity field before creation of singularities are given. The main goal of this paper is to show that this quantity, να+\nu_{\alpha}^{+}, is a good measure for the fluctuations of velocity fields in the Burgers turbulence.Comment: 5 pages, 3 figure

    Flexural performance of reinforced concrete beams strengthened with prestressed near-surface-mounted FRP reinforcements

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    YesA numerical method for estimating the curvature, deflection and moment capacity of reinforced concrete beams strengthened with prestressed near-surface-mounted (NSM) FRP bars/strips is presented. A sectional analysis is carried out to predict the moment–curvature relationship from which beam deflections and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of prestressed FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between experimental results available in the literature and predicted curvature, moment capacity and deflection of reinforced concrete beams with prestressed NSM FRP reinforcements show good agreement. A parametric study concluded that higher prestressing levels improved the cracking and yielding loads, but decreased the beam ductility compared with beams strengthened with nonprestressed NSM FRP bars/strips

    Performance evaluation and optimisation of post combustion CO2 capture processes for natural gas applications at pilot scale via a verified rate-based model

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    CO2 absorption based on chemical reactions is one of the most promising technologies for post combustion CO2 capture (PCC). There have been significant efforts to develop energy efficient and cost effective PCC processes. Given that PCC is still maturing as a technology, there will be a continuing need for pilot scale facilities to support process optimisation, especially in terms of energy efficiency. Pilot scale PCC facilities, which are usually orders of magnitude smaller than those that will be used in future in large scale fossil power plants, make it possible to study details of the PCC process at an affordable scale. However, it is essential that pilot scale studies provide credible data, if this is to be used with confidence to envisage the future large-scale use of the PCC process, especially in terms of energy consumption. The present work therefore establishes and experimentally verifies (using a representative pilot plant as a case study) procedures for analysing the energy performance of a pilot scale amine based CO2 capture plants, focusing on natural gas fired applications. The research critically assesses the pilot plant’s current energy performance, and proposes new operating conditions and system modifications by which the pilot plant will operate more efficiently in terms of energy consumption. The methodology developed to assess and improve the energy performance of the PCC process is applicable, with appropriate inputs, to other plants of this type that employs aqueous 30 wt. % monoethanolamine (MEA) solution as the solvent. A rate based model of the post combustion CO2 capture process using an aqueous solution of 30 wt. % MEA as the solvent was developed in Aspen Plus® V.8.4, and verified using the results of experimental studies carried out using the UK Carbon Capture and Storage Research Centre / Pilot-scale Advanced Capture Technology (UKCCSRC/PACT) pilot plant, as a representative pilot-scale capture plant, and employed for parametric sensitivity studies. Several parameters have been identified and varied over a given range of lean solvent CO2 loading to evaluate their effects on the pilot plant energy requirement. The optimum lean solvent CO2 loading was determined using the total equivalent work concept. Results show, for a given packing material type, the majority of energy savings can be realised by optimising the stripper operating pressure. To some extent, a higher solvent temperature at the stripper inlet has the potential to reduce the regeneration energy requirement. A more efficient packing material, can greatly improve the pilot plant overall energy and mass transfer efficiency
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