1,091 research outputs found
A modelling methodology for a solar energy-efficient neighbourhood
No full textPurpose: The purpose of this paper is to present a methodology to quantify the solar energy potential for applying photovoltaic systems and find an efficient geometry for urban blocks to obtain a better quality of daylighting in terms of continuous daylight autonomy (DA) and spatial DA with less energy consumption. Design/methodology/approach: The paper is based on a complete simulation of the topography and micro-climate of the area under study. Simulations were performed using ArcGIS and Rhinoceros and urban daylight (UD) and urban modeling interface plugin for a neighborhood in the region of Narmak in Tehran, Iran. Five configurations of a neighborhood were compared using simulations. Findings: It was found that the impact of the geometrical form on daylight gain and energy consumption is significant and the terraced model is the most suitable form for obtaining a constant floor area ratio. Furthermore, it is an optimal form of urban blocks to gain the most energy through photovoltaic systems in the neighborhood as it would be able to satisfy about 42 percent of the energy needs. Originality/value: Planning to achieve sufficient energy factors in cities is a difficult task, since urban planners often do not have adequate technical knowledge to measure the contribution of solar energy in urban plans and this paper aims to introduce a comprehensive modeling methodology by which the urban energy planning can be used and understood in the urban context to make it completely clear as a strategy of implementation
A Scalable Framework for Multi-Robot Tele-Impedance Control
No full textIn this article, we present an online scalable tele-impedance framework, which enables the individual and collaborative control of multiple different robotic platforms. The framework provides an intuitive low-cost interface with visual feedback and a SpaceMouse, through which the operator can define the desired task-level trajectories and impedance profiles. With a simple mouse click, the user can switch between the robots and the collaborative operation mode. The control, subsequently, manages the distribution of the required parameters into the involved robots. Thanks to the introduced virtual hand concept, where each robot is defined as a finger, new robots can be easily added or removed via their kinodynamic parameters. The proposed framework was evaluated with three different experiments: a simulated auscultation on a mock-up patient, a cooperative task where a robot drives the patient on a wheelchair and a different robot performs the auscultation, and a collaborative task where two robots relocate a container. The results demonstrate the capabilities of the framework in terms of adaptability to different robotic platforms, the number of robots involved, and the task requirements. Additionally, quantitative and subjective analysis of 12 subjects showed how the developed interface, even in the presence of inaccurate visual feedback, allowed a smooth and accurate execution of the tasks
Shelf life extension of white mushrooms (Agaricus bisporus) by low temperatures conditioning, modified atmosphere, and nanocomposite packaging material
No full textIn this work, we have explored a new integrated approach for the shelf life extension of button mushrooms (Agaricus bisporus). The effect of temperature (4 °C and 25 °C), packaging configuration (PET/coating/LLDPE oxygen barrier material over conventional PVC stretchable film), and modified atmosphere (15% O2/5% CO2/80% N2 over air) were monitored during 10 days of storage. The influence of a chitosan coating deposited on the cap surface was also investigated. Temperature was the most important factor in preserving the quality attributes of mushrooms over time. The test material had a positive impact on weight loss, cap opening percentage, and firmness of mushrooms compared with the control film (∼1.0% versus ∼7.1%; ∼55% versus ∼65%; and ∼10.3 N versus ∼7.6 N, respectively), which was ascribed to the excellent and good oxygen and water vapor barrier properties of the new material, respectively. Mushrooms packaged under the modified atmosphere behaved decidedly better after a prolonged storage time of 22 days at 4 °C. Impressively, after this extended temporal window, the mushrooms looked freshly packed by fully recovering their original color. We explained this striking observation in consideration of the oxygen that permeated the package during these additional 12 days of storage, which would have promoted a gradual resumption of respiratory activity in the overall metabolism of the mushrooms after the “freezing” effect of the rich-CO2 atmosphere inside the package
Impact of magnetic fields on calculated AAPM TG-43 parameters for 192Ir and 60Co HDR brachytherapy sources: A Monte Carlo study
No full textPurpose: The aim of this work is to investigate the influence of an external magnetic field (MF) on The American Association of Physicists in Medicine (AAPM) No. 43 Report (TG-43) parameters for 192Ir and 60Co high dose rate (HDR) brachytherapy sources using Monte Carlo (MC) simulation methods. Materials and methods: We used the Geant4 toolkit (version 10.1. p01) to simulate the geometry of 192Ir and 60Co brachytherapy sources. AAPM TG-43 parameters (the radial dose function, g(r), and the anisotropy function, F (r, θ)) of both 192Ir and 60Co sources were calculated in the presence of a magnetic field with strengths of 1.5T, 3T, and 7T in the X, Y, and Z directions in a voxelized water phantom. Results: For the 192Ir source, the calculated values g(r) and F (r, θ) remained nearly unaffected by the magnetic field for all investigated strengths. For the 60Co source, the differences for the g(r) and F (r,θ) under the 1.5T, 3T, and 7T magnetic field strengths along the direction parallel with the MF were found to be an increase of up to 5%, 15%, and 33%, respectively. However, for the directions perpendicular with the magnetic field, there was a decrease of up to 3%, 6% and 15% under 1.5T, 3T and 7T strengths, respectively. Conclusion: Our results highlight the necessity of a Monte Carlo-based treatment planning system (TPS) if cobalt HDR treatments are performed under a magnetic field, especially for strengths greater than 1.5T
Experimental parametric study on dynamic divergence instability and chaos of circular cylindrical shells conveying airflow
No full textExperiments have shown that soft circular cylindrical shells supported at both ends and conveying airflow lose stability by so-called dynamic divergence. The present study investigates experimentally the effect of geometric parameters of a silicone rubber shell, namely length-to-radius (L/R) and thickness-to-radius (h/R) ratios, on the dynamic divergence instability. Bifurcation diagrams of the rms velocity of the shell vibration versus flow velocity are obtained for different shells, displaying a strongly subcritical nonlinear behaviour. Then, the onset of instability and post-critical behaviour of the shells are compared: (i) thinner and longer shells lose stability at lower flow velocities, (ii) thinner shells have higher rms vibration velocity, and (iii) by decreasing L/R, the subcritical behaviour is weakened for thin shells, while it is strengthened for thick shells. The existence of chaos and the influence of geometric parameters on the chaotic behaviour of the system are deeply examined by means of several measures
Tripose: A weakly-supervised 3d human pose estimation via triangulation from video
No full textGholami M, Rezaei A, Rhodin H, Ward R, Wang ZJ. Tripose: A weakly-supervised 3d human pose estimation via triangulation from video. arXiv preprint arXiv:2105.06599. 2021
Self-Supervised 3D Human Pose Estimation in Static Video Via Neural Rendering
No full textGholami M, Rezaei A, Rhodin H, Ward R, Wang ZJ. Self-Supervised 3D Human Pose Estimation in Static Video Via Neural Rendering. Neurocomputing. 2022;488:97-106
AdaptPose: Cross-Dataset Adaptation for 3D Human Pose Estimation by Learnable Motion Generation
No full textGholami M, Wandt B, Rhodin H, Ward R, Wang ZJ. AdaptPose: Cross-Dataset Adaptation for 3D Human Pose Estimation by Learnable Motion Generation. In: Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition. 2022: 13075-13085
A novel triple-diameter pulsating heat pipe: Flow regimes and heat transfer performance
No full textA single-turn triple-diameter pulsating heat pipe (TD-PHP) with a total length of 250 mm (the evaporation, adiabatic, and condensation lengths were 25 mm, 125 mm, and 100 mm, respectively) made of a transparent Pyrex glass was designed and fabricated for the first time. The thermal performance and flow characteristics of the TD-PHP were compared with two other fabricated PHPs, the single-diameter (SD) and dual-diameter (DD) PHPs, to determine the effect of non-uniform channel diameters. The PHPs were mounted on a tilting frame, and their thermal performances were tested with various heat inputs, inclination angles, and filling ratios. The temperatures of the evaporation, condensation, and adiabatic sections and flow behaviors were monitored. Results indicated that circulating flow was enhanced by using TD-PHP, and thermal resistance was reduced considerably. The visualization results showed that the bubbles' generation, growth, and breakage leading to enlarged vapor plugs were enhanced because of the unbalanced gravitational forces owning to the channel with non-uniform diameter. Hence, the TD-PHP was functional even at inclination angles near the horizontal angle
A Shared-Autonomy Approach to Goal Detection and Navigation Control of Mobile Collaborative Robots
No full textAutonomous goal detection and navigation control of mobile robots in remote environments can help to unload human operators from simple, monotonous tasks allowing them to focus on more cognitively stimulating actions. This can result in better task performances, while creating user-interfaces that are understandable by non-experts. However, full autonomy in unpredictable and dynamically changing environments is still far from becoming a reality. Thus, teleoperated systems integrating the supervisory role and instantaneous decision-making capacity of humans are still required for fast and reliable robotic operations. This work presents a novel shared-autonomy framework for goal detection and navigation control of mobile manipulators. The controller exploits human-gaze information to estimate the desired goal. This is used together with control-pad data to predict user intention, and to activate the autonomous control for executing a target task. Using the control-pad device, a user can react to unexpected disturbances and halt the autonomous mode at any time. By releasing the control-pad device (e.g., after avoiding an instantaneous obstacle) the controller smoothly switches back to the autonomous mode and navigates the robot towards the target. Experiments for reaching a target goal in the presence of unknown obstacles are carried out to evaluate the performance of the proposed shared-autonomy framework over seven subjects. The results prove the accuracy, time-efficiency, and ease-of-use of the presented shared-autonomy control framework
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