scholarly journals A Study on Decisional Factors for Service Life of Fire Trucks

2021 ◽  
Vol 35 (5) ◽  
pp. 32-37
Author(s):  
Chang-Sub Chun ◽  
Seung-Mo Kim
Keyword(s):  
Service Life ◽  
Service Time ◽  
Natural Water ◽  
Erosion Rate ◽  
Small Magnitude ◽  
Pump Failure ◽  
Principal Role ◽  
High Erosion Rate ◽  
Fire Accident ◽  
Main Factor

The lifetime of fire trucks depends on their built-in pumps. A fire truck delivers water to the site of a fire accident via its pump that is composed of an impeller and a casing. As its service time increases, the clearance between the two elements increases. This causes leakage in the pump to increase beyond its limit and the pump can no longer fulfill its principal role. In general, fatigue, erosion, and corrosion are considered to be the major mechanisms for pump failure. From this study, it has been observed that fatigue is not the main factor for failure because of the small magnitude of stress it induces. Erosion by particles shows a high erosion rate of the suction area of the impeller. Cavitation, which is a key mechanism of corrosion, is observed at a suction depth of 7 m and is observed to widen at 7.1 m depth. Finally, the lifetime of the fire trucks is found to be affected by the motion of sucking the natural water of ponds, rivers, etc.

Estimation of Service Life of Mechanical Engineering Components

2019 ◽  
Vol 799 ◽  
pp. 71-76
Author(s):  
Oskars Linins ◽  
Ernests Jansons ◽  
Armands Leitans ◽  
Irina Boiko ◽  
Janis Lungevics
Keyword(s):  
Service Life ◽  
Service Time ◽  
Surface Texture ◽  
Mechanical Engineering ◽  
Friction Pair ◽  
Theory Of Elasticity ◽  
New Approach ◽  
Material Fatigue ◽  
Texture Parameters ◽  
3D Surface Texture

The paper is aimed to the methodology for estimation of service life of mechanical engineering components in the case of elastic-plastic contact of surfaces. Well-known calculation methods depending on physics, theory of probability, the analysis of friction pair’ shape and fit include a number of parameters that are difficult or even impossible to be technologically controlled in the manufacturing of mechanical engineering components. The new approach for wear rate estimation using surface texture parameters as well as physical-mechanical properties and geometric parameters of components is proposed. The theoretical part of the calculations is based on the 3D surface texture principles, the basics of material fatigue theory, the theory of elasticity and the contact mechanics of surfaces. It is possible to calculate the service time of the machine, but the process of running-in of the components is relatively short (less than 5%), therefore, the service time is mainly determined by a normal operating period, which also was used to evaluate this period. The calculated input parameters are technologically and metrologically available and new method for calculating the service time can be used in the design process of the equipment. The results of approbation of the method for estimation service time of mechanical engineering, which prove the applicability of mentioned method, are offered as well.

Analysis of Circuit Junction of Automatic Fire Alarm System

2013 ◽  
Vol 416-417 ◽  
pp. 1111-1114
Author(s):  
Meng Lu Yu
Keyword(s):  
Economic Development ◽  
Building Design ◽  
Alarm System ◽  
Fire Alarm ◽  
Structural Layout ◽  
Internal Structures ◽  
Fire Alarm System ◽  
Security Problem ◽  
Fire Accident ◽  
Main Factor

Security problem is the main factor restricting economic development of architecture. Fire accident, in particular, results in serious casualties and losses. As building structural layout is more diversified, there are more and more assembly forms of internal structures and facilities. Automatic fire alarm system is the key in building design and construction. The thesis first of all makes an analysis of the current construction fire accident, points out the application function of fire alarm system and analyzes automatic fire alarm system circuit junction, hoping to contribute to further studies.

Study on Numerical Simulation of Gas-Solid Erosion for Feed Type Tee

2017 ◽  
Author(s):  
Zhou Fang ◽  
Weiwei Hu ◽  
Deyu Liu ◽  
Guanghai Li
Keyword(s):  
Numerical Simulation ◽  
Service Life ◽  
Erosion Rate ◽  
Solid Particles ◽  
Phase Flow ◽  
Gas Velocity ◽  
Two Phase ◽  
Distribution Method ◽  
Air Blowing ◽  
Fluent Software

A series of numerical simulation about gas-solid erosion for feed type tee have been taken out. The gas-solid two phase flow was formed in the tee with the solid particles coming from the top of the tee pipes and air blowing from the left side. Tee pipes erosion situation was simulated by DPM model in Fluent software. The serious erosion location in the tee pipes was analyzed with different speeds of solid and air. The reasonable distribution method of the particle velocity and gas velocity was put forward and the particles were remained in the intermediate position of the pipes. So the collision with the wall was reduced, and the pipeline erosion rate was slowed down, in addition, the service life of pipes was prolonged.

scholarly journals The Impact of Land Use on Hydrological Characteristics and Erosion Rate of Cilutung Watershed with SWAT Model

2018 ◽  
Vol 73 ◽  
pp. 03029
Author(s):  
Nadzira Fadhilah ◽  
Eko Kusratmoko ◽  
Kuswantoro
Keyword(s):  
Land Use ◽  
Statistical Analysis ◽  
Erosion Rate ◽  
Swat Model ◽  
Erosion Rates ◽  
High Erosion Rate ◽  
Acceptable Model ◽  
High Runoff ◽  
The Impact

Cimanuk watershed will be affected directly by the dynamics of Cilutung watershed as one of its tributaries. Cimanuk is one of the watershed areas in West Java Province, that is categorized as a critical potential due to erosion and vegetation damage. This study aims to simulate hydrological conditions and erosion rates for each sub-watershed. This research uses several variables: 1) soil type; 2) topography; 3) land use; and 4) climate (temperature, rainfall, solar radiation, wind speed, and relative humidity). Analysis conducted is Hydrology Response Units (HRUs) and statistical analysis. Variable physical characteristics are processed by the overlay method for HRUs analysis. Statistical analysis showed the values of R2 and NSE were 0.48 and 0.32. Based on the calibration and validation results, the values of R2 and NSE are 0.75 and 0.46. This shows a satisfactory and acceptable model. The runoff value tends to show a moderate category between 50-80 in the category of Coefficient of Flow Regime and this is precisely proportional to the rate of erosion. Each sub-watershed shows a high runoff value, tends to produce high erosion rate as well and its reverse. The rate of erosion indicates 175.0 tons/ha / year in the medium category.

Some Possible Alternatives for Longer-Life Locomotive Wheels

2002 ◽  
Author(s):  
Cameron Lonsdale ◽  
Daniel Stone
Keyword(s):  
Service Life ◽  
Service Time ◽  
Wheel Rim ◽  
Repair Costs ◽  
Martensitic Microstructure ◽  
Wear Life ◽  
Wide Range ◽  
Alternative Materials ◽  
Points Of View ◽  
Locomotive Wheels

An increase in the wear life of locomotive wheels is considered desirable from the locomotive builder and railroad user points of view. If a wheel has a longer service life, economics are improved due to less locomotive out-of-service time, reduced maintenance repair costs and reduced wheel renewal costs. This paper discusses possible alternative materials and microstructures that could be used for longer-life locomotive wheels, and also tires. If locomotive builders and users consider wheel rim hoop compression essential, then microalloying and increased carbon content are perhaps the most likely courses of action to improve wheel life. If rim hoop compression is not considered essential, a wide range of alternatives become possible including bainitic and martensitic microstructure monobloc wheels and tires.

scholarly journals Soil Erosion Estimation Using RUSLE Modeling and Geospatial Tool: Case Study of Kathmandu District, Nepal

2020 ◽  
Vol 17 ◽  
pp. 118-134
Author(s):  
Roshan Dahal
Keyword(s):  
Soil Erosion ◽  
Spatial Data ◽  
Soil Loss ◽  
Erosion Rate ◽  
Slope Length ◽  
Erosion Rates ◽  
High Erosion Rate ◽  
Time Savings ◽  
Data Screening

Revised Universal Soil Loss Equation (RUSLE) model is applied in this study to evaluate the risk of erosion in Kathmandu district. The calculation of erosion requires certain data from various sources available in different formats and scales. Geographic Information System (GIS) was used which allowed considerable time savings in the processing of spatial data, screening the effects of each factor affecting soil erosion. Among various erosion factors, topography, rainfall, soil properties, and soil conservation practices were used for the study. Average soil loss was calculated by multiplying these factors. Final results of soil erosion rates were separated into six classes based on erosion severity, in which 2.18% of land (> 80Mg ha-1yr-1), followed by 2.85% of land (40-80 Mg ha-1yr-1), 5.56% of land (20-40 Mg ha-1yr-1), 8.73% of land (10-20 Mg ha-1yr-1), 10.53% of land (5-10 Mg ha-1yr-1) and 70.14% of land (0-5 Mg ha-1yr-1), falls under very severe, severe, very high, moderate and low severity zone respectively. Area having high slope length (LS) factor has high erosion rate. In Dakshinkali, Nagarjun and Budanilkantha area, there is high erosion rate. From the result, spatial distribution of soil erosion across Kathmandu district, can be applied for management and controlling the erosion.

Numerical Simulation of Insulation Layer Ablation in Solid Rocket Motor Based on Fluent

2014 ◽  
Vol 574 ◽  
pp. 224-229
Author(s):  
Jian Li ◽  
Mei Zhang ◽  
Jiang Tao Zhang
Keyword(s):  
Particle Deposition ◽  
Erosion Rate ◽  
Burning Surface ◽  
Rocket Motor ◽  
Insulation Material ◽  
Insulation Layer ◽  
Solid Rocket Motor ◽  
High Erosion Rate ◽  
Discrete Phase ◽  
Solid Rocket

A two-dimensional axisymmetric model was constructed to predict the ablation of the insulation layer in an end burning rocket motor by using the Computational Fluid Dynamics (CFD) software Fluent. The insulation material of graphite was used in the model. The wall surface reactions and discrete phase erosion were applied to simulate the insulation layer ablation. The influence of the burning surface movement was analyzed by using the dynamic mesh method. Numerical results show that the erosion rate increase with the increasing of burning time. The maximum erosion rate occurs at the upstream of the nozzle throat. There has a high erosion rate closing to the burning surface, and it decreases gradually away from the burning surface and becomes zero near the nozzle. It’s found that solid particle deposition appears on the inner surface of combustor closing to the nozzle, and it increases with the increasing of time.

scholarly journals Morphogenesis of the Sarine canyon in the Plateau Molasse, Switzerland : new data from an archaeological site

2008 ◽  
Vol 63 (3) ◽  
pp. 181-187 ◽  
Author(s):  
L. Braillard ◽  
M. Mauvilly
Keyword(s):  
Erosion Rate ◽  
Archaeological Site ◽  
Late Glacial ◽  
Early Holocene ◽  
Atlantic Period ◽  
River Bed ◽  
High Erosion Rate

Abstract. The 50 to 100 metre deep canyon of the Sarine River that develops north of the prealpine front in the Molasse Plateau is classically attributed to postglacial erosion. However, the discovery of a Mesolithic archaeological site (~ 8600 years cal. BP), located at the bottom of the gorge five metres above the actual river bed, has evident implications for the canyons morphogenesis. This new chronological datum indicates that most of the canyon was already formed 8600 years ago, and that only five metres of Molasse have eroded since that time. This implies a dramatically high erosion rate during Late Glacial to early Holocene times 0.9 to 1.48 cm/ year) and, consequently, a very low erosion rate since the Atlantic period approximately 0.06 cm/ year). These new archaeological and geological findings offer exciting perspectives for Quaternary research.

Role of Transcriptional Read-Through in PRE Activity in Drosophila melanogaster

Acta Naturae ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 79-86 ◽  
Author(s):  
P. V. Elizar’ev ◽  
D. V. Lomaev ◽  
D. A. Chetverina ◽  
P. G. Georgiev ◽  
M. M. Erokhin
Keyword(s):  
Dna Sequences ◽  
Cell Types ◽  
Transcription Terminator ◽  
Response Elements ◽  
Polycomb Response Elements ◽  
The Individual ◽  
Multicellular Organisms ◽  
Different Cell Types ◽  
Main Factor

Maintenance of the individual patterns of gene expression in different cell types is required for the differentiation and development of multicellular organisms. Expression of many genes is controlled by Polycomb (PcG) and Trithorax (TrxG) group proteins that act through association with chromatin. PcG/TrxG are assembled on the DNA sequences termed PREs (Polycomb Response Elements), the activity of which can be modulated and switched from repression to activation. In this study, we analyzed the influence of transcriptional read-through on PRE activity switch mediated by the yeast activator GAL4. We show that a transcription terminator inserted between the promoter and PRE doesnt prevent switching of PRE activity from repression to activation. We demonstrate that, independently of PRE orientation, high levels of transcription fail to dislodge PcG/TrxG proteins from PRE in the absence of a terminator. Thus, transcription is not the main factor required for PRE activity switch.

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