scholarly journals Risk Analysis of One-Way Road Tunnel Tube Used for Bi-Directional Traffic under Fire Scenarios

2021 ◽  
Vol 11 (7) ◽  
pp. 3198
Author(s):  
Ciro Caliendo ◽  
Isidoro Russo ◽  
Gianluca Genovese
Keyword(s):  
Risk Analysis ◽  
Environmental Conditions ◽  
Natural Ventilation ◽  
Probabilistic Approach ◽  
Cfd Modeling ◽  
Risk Level ◽  
Road Tunnel ◽  
Positive Effects ◽  
Visibility Distance ◽  
Traffic Volumes

We have set up a Computational Fluid Dynamics (CFD) modeling, and performed a user evacuation model, for evaluating the risk level in one-way road tunnel tube when used for bi-directional traffic in particular circumstances. The simulations were carried out by considering both peak-hour traffic volumes during the day and off-peak hours overnight. The investigated one-way tube is ventilated by natural ventilation only, and has a length of less than 1000 m. With reference to the worst environmental conditions, which are downstream of the fire due to the direction of natural ventilation, the consequences on escaping users, caused by different types of burning vehicles located in various longitudinal positions along the tube, are shown. The results prove the positive effects on environmental conditions (in terms of temperature, visibility distance, CO and CO2 concentration) along the user evacuation path when the tube is used for bi-directional traffic at night rather than daytime. Only for the case of 100 MW fire and in the proximity of the exit portal, the last escaping user might be affected by a visibility distance and CO concentration exceeding the threshold values. In this special case, countermeasures for reducing smoke concentration or emergency services at the portals should be provided. However, the quantitative risk analysis, based on a probabilistic approach, showed that the F-N curve of the tube when used for bi-directional traffic with reference to the night always lies below that of the daytime, and the reduction in the risk level is between 80 and 100% for the night traffic compared to daytime one. It is to be focused on the fact that our modeling may represent a reference in investigating the effects of hourly traffic volumes on the risk level in tunnels and may help decisionmakers in understanding when to temporarily close a tube for maintenance, repair, or rehabilitation activities and use the adjacent tube for bi-directional traffic.

scholarly journals PROBABILISTIC APPROACH TO MEASURING PRICE RISK OF THE ENTERPRISE

2021 ◽  
Vol 138 (4) ◽  
pp. 19-35
Author(s):  
MAKARCHUK Ivan ◽  
FEDULOVA Iryna
Keyword(s):  
Risk Assessment ◽  
Distribution Function ◽  
Probability Distribution ◽  
Risk Analysis ◽  
Probabilistic Approach ◽  
Market Price ◽  
Random Variables ◽  
Risk Level ◽  
Price Risk ◽  
Key Indicators

Background. Every manager faces analyzing problem and forecasting indicators in the process of making management decisions that are random variables, and therefore they are associated with risk and uncertainty. Their realization is possible in the future, but today we need to understand the risk level that can be encountered in the activity process and prepare for it in advance. Analysis of recent research and publications has shown that probabilistic approach is the most commonly used tool for risk assessment and it is based on probability theory. The aim of the article is to consider the tools of the probabilistic approach to riska ssessment. According to this approach, risk assessment is carried out for products price that have a normal law distribution and for which we can use an integrated probability distri­bution function and the key indicators that underlie its structure. Materials and methods. The methodological basis of risk analysis by the probabilistic approach is the consideration of the initial data as expected values of some random variables with known laws of probability distribution. Results. The use of tools of probabilistic approach to risk assessment of product pricing is considered. It is based on the assumption that a normal probability distribution law, an integral probability distribution function, and the key indicators that underlie its construction can be used to analyze market price risk. Conclusion. Probabilistic approach allows with minimal effort to understand the probability of obtaining the desired result, which is related to the purpose of the enterprise, or which result can be obtained with the desired probability and determine their acceptability. Keywords: risk, risk analysis, risk assessment, probabilistic approach, integral pro­bability distribution function.

CFD Modeling of Pressure Coefficients for a Natural Ventilation Study in an Experimental Low Rise Building

2013 ◽  
Author(s):  
Robel Kiflemariam ◽  
Cheng-Xian Lin
Keyword(s):  
Natural Ventilation ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Analytical Models ◽  
Cfd Modeling ◽  
Engineering Practice ◽  
Pressure Coefficients ◽  
Wind Pressure Coefficient ◽  
Detailed Assessment ◽  
Ventilation Rates

Mean wind pressure coefficient (Cp) is one of the major input data for natural ventilation study using building energy simulation approach. Due to their importance, they need to be accurately determined. In current engineering practice, tables and analytical Cp models only give mostly averaged results for simpler models and configurations. Considering the limitation of tables and analytical models, Computational Fluid Dynamics (CFD) could provide a means for an accurate and detailed assessment of Cp. In this paper, we make use of a relatively high resolution, detailed experiments done at Florida Intentional University to validate a CFD modeling of the pressure coefficients Cp. The results show that existing CFD model has a good agreement with experimental results and gives important information of distribution of Cp values over the surface. The local values of the Cp are investigated. In addition, the CFD derived Cp and discharge coefficient (Cd) values are utilized in semi-analytical ventilation models in order to get a more accurate value of ventilation rates.

scholarly journals Risk Analysis of Vegetables Marketing in Rwanda, A case of carrots and cabbages produced in Rubavu District and supplied across the country

2020 ◽  
Vol 56 (2) ◽  
Author(s):  
Jean Jacques KUBWIMANA
Keyword(s):  
Risk Analysis ◽  
Linear Regression Analysis ◽  
Secondary Data ◽  
Primary Data ◽  
Risk Level ◽  
Bivariate Analysis ◽  
Market Demand ◽  
Contractual Arrangements ◽  
Marketing Risk ◽  
Storage Network

Due to the perishable nature and biological nature of the production process there is difficulty in scheduling the supply of vegetables to market demand. The vegetables are subjected to higher prices and quantity risks with changing consumers’ demand and production conditions. The core focus of this study was to reach, measure, and analyzing the marketing risk level of vegetables produced in Rubavu District, Rwanda. The study based on a survey of 90 vegetable sellers. At least 30 couple of wholesalers and middlemen visited Rubavu District to trade the vegetables for various retails. Primary data collected through structured questionnaires and secondary data sources used. A Five-point Likert associated with the bivariate analysis was used to rank the risk level while the full model of Linear Regression Analysis and factor analysis were used to identifier the majors’ factors associated with the risk in vegetable marketing in Rwanda. The mean score results derived based on Likert-Scales, indicated that “low seasonal product prices, weak market channels, poor logistics, and market communications, poor product handling and packaging, lack of storage and higher perishability’ identified to be the most important sources of risk. Therefore, the use of forwards’ contracts; getting market information, sell at crude prices due to perishability, contractual arrangements, maintaining good relationships and restoring the storage network system were of significant concerns for overcoming the recognized risks.   Keywords: Risk, Risk analysis, Likert Scale, Marketing risk, Vegetable Marketing risk, and Risk Management.

scholarly journals Studying and evaluating the performance of pedestrian crossing facilities in Babil governorate

2019 ◽  
Vol 28 (3) ◽  
pp. 417-431
Author(s):  
Ali Dakhil ◽  
Dheyaa Alobaidi ◽  
Saba Shaheed
Keyword(s):  
Fundamental Problem ◽  
Health Department ◽  
Positive Effects ◽  
Pedestrian Bridges ◽  
Traffic Volumes ◽  
Interview Survey ◽  
The One ◽  
Questionnaire Method ◽  
Pedestrian Crossing ◽  
In Transit

Walking is one of the oldest means of mobility. It is an indispensable necessity to reach destinations despite the fact that walking or walking is one of everyday activities of man, which have positive effects on health, and activity on the one hand; vehicles cannot reach destinations only required by often walking from the other. The main problem address by the research is the random passage of the sieve and uncontrolled when it is most designs for the city’s road network have not addressed. This fundamental problem as well as the lack of a city to the safe facilities to cross the pedestrian. Therefore, this paper is a trial to study and analyze the current reality of crossing the sap then find solutions and treatments that reduce or limit the overlap between different traffic events and events crossing the pedestrian. Field data on the syllabic traffic volumes collected in all areas of the study (peak hour volume) and the photographic technique method. The study chose four areas to study the sap (60th Street, 40th Street, Al-Hussein, intersection circle at Babel Health Department), which are residential, commercial and educational zones, representing diversity in land use and scheme sidewalk and the design of the city of Hilla. The study attempted to show the state of lateral walks. The study also used the questionnaire method (interview survey) to determine the suitability of pedestrian bridges in transit and land transit. The study concluded that the area of Al-Hussein represents the highest traffic volumes of the sieve in addition to the lack of it the sidewalks in terms of absorption and quality and abuses. As well as the reluctance to use pedestrian bridges in transit in the area of 60th Street through high ground transit time, which necessitates the establishment of dual-step (fixed and mobile) – legislation and education through all means.

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals ANALISIS POLA DAN RESIKO USAHA GULA AREN DI KABUPATEN REJANG LEBONG

2012 ◽  
Vol 11 (1) ◽  
pp. 1-11
Author(s):  
Felycia Tyera Kencana ◽  
Ketut Sukiyono ◽  
Bambang Sumantri
Keyword(s):  
Risk Analysis ◽  
Rainy Season ◽  
Descriptive Analysis ◽  
Simple Random Sampling ◽  
Dry Season ◽  
Risk Level ◽  
Cluster Sampling ◽  
Production Scale ◽  
Research Areas ◽  
Palm Sugar

This study is aimed at examining enterprises model and analysing risk level of Palm Sugar in Rejang Lebong Regency.  Risk Analysis involve nira harvested, nira processed, palm sugar production, and palm sugar prices received by producers.  Two-stages cluster sampling method is used to determine research areas, i.e, subdistrict of Sindang Kelingi and Selupu Rejang based on the numbers of  firms. Using similar critirea, two villages are selected, i.e, Air Meles Atas and Sindang Jati.  From those villages, then, 86 palm sugar producers are selected using Simple Random Sampling. Descriptive analysis is applied to describe entreprises model of palm sugar industries while risks is analysed using its varians, standard deviation, and minimum level of production as proposed by Maryam and Suprapti (2008).   The research shows that all palm sugar industries in this regency can be categories as home industries with average production scale of  11.58 kg per process in rainy season and 11. 54 kg in dry season. Palm sugar producers  use  their own capital to produce palm sugar and borrowed to palm sugar village merchants when they need.  From risk analysis, the study finds that palm sugar producers will face higher risk in term of nira harvested and processed, and production in dry season, except in term of price received which is higher in rainy season.  Over all, palm sugar producers will not face risk significantly both in dry and rainy season.Key words: Palm Sugar, Enterprises model, Risk analysis       

A WebGIS-Based System for Urban Stormwater Risk Analysis Using a Cloud Matter-Element Model

2020 ◽  
Vol 16 (3) ◽  
pp. 80-99
Author(s):  
Junfei Chen ◽  
Cong Yu
Keyword(s):  
Risk Assessment ◽  
Risk Analysis ◽  
Temporal Distribution ◽  
Element Model ◽  
Economic Loss ◽  
Risk Level ◽  
Urban Stormwater ◽  
Intelligence System ◽  
Prototype Development ◽  
Matter Element Model

The interaction of human activity, climate change, and urbanization gives rise to more frequent urban stormwater disasters, which causes great economic loss in cities. This article presents a prototype of an interactive WebGIS system for urban stormwater risk analysis. The system has a Browse/Server(B/S) structure and uses WebGIS techniques for prototype development. It is based on the theory of disaster system and Cloud matter-element model for risk assessment. The risk results are immediately generated and visualized interactively by rendering risk maps. Finally, two urban stormwater events in Nanjing in 2015 and 2016 were selected to verify the accuracy of the risk assessment. The results show that the intelligence system can effectively assess the risk level and identify the spatial-temporal distribution of urban stormwater risk in Nanjing, China.

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