33 research outputs found

    Pedestrian street and its effect on economic sustainability of a historical Middle Eastern city: the case of Chaharbagh Abbasi in Isfahan, Iran

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    Pedestrianization is an urban revitalization strategy to enhance sustainability and livability in car-oriented cities. Despite many studies in this research field, the effects of pedestrianization on the economy of cities in developing countries still need further investigation. Additionally, the impact of this strategy on the tenant mix of commercial and historical areas in Middle East countries is nebulous. To address these inadequacies, we considered Chaharbagh Abbasi street, located in the heart of Isfahan, Iran, and investigated the impact of a pedestrianization project with particular emphasis on how it affects the economic sustainability of existent commercial fabric. Pre and post-project data along with field observations and quantifications used to assess structural replacements in trade, were analyzed with SPSS and ArcGIS software. The results revealed unexpected outcomes, such as the closure of some traditional businesses (27.5%), a stagnation in sales (69%) and a decrease in job offers (84%) leading the local economy to a fragile situation. Conversely, it was found that the footfall volume increased by 64% and 73% from the retailers’ and pedestrians’ viewpoints. This evolution along with a wide opening of food and beverage stores (approximately 60%) makes the post-pedestrianization results more promising than earlier predictions. In conclusion, these findings reinforce the importance of pedestrian streets in revitalizing economic activities in historical and commercial areas from the perspective of economic sustainability. Due to the lack of similar investigations in Middle East countries, these findings can support decision-makers and urban planners to take preventive measures in preserving the diversity of individual small shops for upcoming urban rehabilitation projects in terms of pedestrianization.info:eu-repo/semantics/acceptedVersio

    Analysis and modeling time headway distributions under heavy traffic flow conditions in the urban highways: case of Isfahan

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    The time headway of vehicles is an important microscopic traffic flow parameter which affects the safety and capacity of highway facilities such as freeways and multi-lane highways. The present paper intends to provide a report on the results of a study aimed at investigating the effect of the lane position on time headway distributions within the high levels of traffic flow. The main issue of this study is to assess the driver's behavior at different highway lanes based on a headway distribution analysis. The study was conducted in the city of Isfahan, Iran. Shahid Kharrazi six-lane highway was selected for collecting the field headway data. The under-study lanes consisted of passing and middle lanes. The appropriate models of headway distributions were selected using a methodology based on Chi-Square test for each lane. Using the selected models, the headway distribution diagrams were predicted for high levels of traffic flow in both the passing and middle lanes and the relationship between statistical criteria of the models and the driver's behaviors were analyzed. The results certify that the appropriate model for the passing lane is different than the one for the middle lane. This is because of a different behavioral operation of drivers which is affected by specific conditions of each lane. Through car-following conditions in the passing lane, a large number of drivers adopt unsafe headways. This shows high risk-ability of driver population which led to considerably differences in capacities and statistical distribution models of two lanes

    CoVR: A Large-Scale Force-Feedback Robotic Interface for Non-Deterministic Scenarios in VR

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    We present CoVR, a novel robotic interface providing strong kinesthetic feedback (100 N) in a room-scale VR arena. It consists of a physical column mounted on a 2D Cartesian ceiling robot (XY displacements) with the capacity of (1) resisting to body-scaled users' actions such as pushing or leaning; (2) acting on the users by pulling or transporting them as well as (3) carrying multiple potentially heavy objects (up to 80kg) that users can freely manipulate or make interact with each other. We describe its implementation and define a trajectory generation algorithm based on a novel user intention model to support non-deterministic scenarios, where the users are free to interact with any virtual object of interest with no regards to the scenarios' progress. A technical evaluation and a user study demonstrate the feasibility and usability of CoVR, as well as the relevance of whole-body interactions involving strong forces, such as being pulled through or transported.Comment: 10 pages (without references), 14 pages tota

    COVID-19 Associated Mucormycosis::A Review of an Emergent Epidemic Fungal Infection in 3 Era of COVID-19 Pandemic

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    At a time when the COVID-19's second wave is still picking up in countries like India, a number of reports describe the potential association with a rise in the number of cases of mucormycosis, commonly known as the black fungus. This fungal infection has been around for centuries and affects those people whose immunity has been compromised due to severe health conditions. In this article, we provide a detailed overview of mucormycosis and discuss how COVID-19 could have caused a sudden spike in an otherwise rare disease in countries like India. The article discusses the various symptoms of the disease, class of people most vulnerable to this infection, preventive measures to avoid the disease, and various treatments that exist in clinical practice and research to manage the disease

    Auxetic structures in civil engineering applications: Experimental (by 3D printing) and numerical investigation of mechanical behavior

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    Auxetic materials are a group of metamaterials that have a negative Poisson's ratio. The most important advantage of auxetics over conventional materials is higher energy absorption. Consequently, in Civil Engineering, a wide range of applications may be considered for auxetic materials including energy absorber structural elements. In this study, two auxetic structures named re-entrant and arrowhead were selected along with the conventional honeycomb structure to investigate the effect of the negative Poisson's ratio on their mechanical behavior. These structures were produced utilizing a fused deposition modeling (FDM) 3D printer. Energy absorption was investigated numerically and experimentally. In order to increase the accuracy of the numerical study, ductile damage for the material was considered. The results showed that the ultimate forces of the re-entrant and arrowhead structures were increased by 125 % and 164 %, respectively, compared to the honeycomb structure. Furthermore, the amount of energy absorption of the re-entrant and arrowhead compared to the honeycomb structure increased by 47.4 % and 176.8 %, respectively. The rate of specific energy absorption in the two mentioned auxetic structures compared to the non-auxetic structure improved by 20.9 % and 53.5 %, respectively

    Modeling a Hybrid Microgrid Using Probabilistic Reconfiguration under System Uncertainties

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    A novel method for a day-ahead optimal operation of a hybrid microgrid system including fuel cells, photovoltaic arrays, a microturbine, and battery energy storage in order to fulfill the required load demand is presented in this paper. In the proposed system, the microgrid has access to the main utility grid in order to exchange power when required. Available municipal waste is utilized to produce the hydrogen required for running the fuel cells, and natural gas will be used as the backup source. In the proposed method, an energy scheduling is introduced to optimize the generating unit power outputs for the next day, as well as the power flow with the main grid, in order to minimize the operational costs and produced greenhouse gases emissions. The nature of renewable energies and electric power consumption is both intermittent and unpredictable, and the uncertainty related to the PV array power generation and power consumption has been considered in the next-day energy scheduling. In order to model uncertainties, some scenarios are produced according to Monte Carlo (MC) simulations, and microgrid optimal energy scheduling is analyzed under the generated scenarios. In addition, various scenarios created by MC simulations are applied in order to solve unit commitment (UC) problems. The microgrid’s day-ahead operation and emission costs are considered as the objective functions, and the particle swarm optimization algorithm is employed to solve the optimization problem. Overall, the proposed model is capable of minimizing the system costs, as well as the unfavorable influence of uncertainties on the microgrid’s profit, by generating different scenarios
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