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Evaluation of the Structure of Urban Stormwater Pipe Network Using Drainage Density

Evaluation of the Structure of Urban Stormwater Pipe Network Using Drainage Density

Abstract: In mega cities such as Seoul in South Korea, it is very important to protect the city from flooding, even for short periods of time due to the enormous amount of economic damage. In impervious areas of the city, a stormwater pipe network is commonly applied to discharge rainfall outside of the catchment. Therefore, the stormwater pipe network in an urban catchment should be carefully designed to discharge the runoff quickly and efficiently. In this study, different types of structures in the stormwater pipe network were evaluated using the relationship between the peak rainfall and runoff in urban catchments in South Korea. More than 400 historical rainfall events were applied in five urban catchments to estimate the peak runoff from different types of network structures. Linear regression analysis was implemented to estimate peak runoffs. The coefficient of determination of the regressions were higher than 0.9, which meant the regression model represented the relationship between the two peaks very well. However, the variation of the prediction became large as the peak rainfall increased and the variation became even larger when the network structure was branched. Therefore, it depends on the structure of the stormwater pipe network. When the water paths in the pipe network are unique (branched network), the increased amount of rainfall is congested around the rainwater inlets and the uncertainty of peak runoff prediction is increased. If there are many possible water paths depending on the amount of discharge (looped network), the increased rainfall is discharged more quickly through the many water paths. This can be a way to represent the reliability of the stormwater pipe network. The structures of the stormwater pipe network were evaluated using drainage density, which is the length of pipes over the unit catchment area and 95% confidence interval. As a result, the 95% confidence interval increased as the drainage density increased and as the accuracy of the peak runoff prediction decreased. As mentioned earlier, as the looped networks have many alternative water flowing paths, the elimination time of rainfall from the catchments becomes short, the 95% confidence interval becomes narrow, and the reliability of the peak runoff prediction becomes high. Therefore, it is beneficial to install a looped stormwater pipe network within an affordable budget. It is an important factor to determine the amount of complexity in the stormwater pipe network to decrease the risk of urban flooding.

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Effect of Pressure dependent demand on pipe network analysis: A case study

Effect of Pressure dependent demand on pipe network analysis: A case study

Water distribution network is most important part of world’s infrastructure. In the present work, analysis for proposed site of school of planning and architecture, Bhopal is done by using demand based analysis and the design is further analyzed for pressure dependent demand. Detailed study of variation of threshold pressure with power function is carried out .Complete site is divided into two zones having two separate water tank for supply and the analysis is done by varying threshold pressure and power function in case of pressure dependent demand by using commercial pipe network analysis software.

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An Efficient Iterative Method for Looped Pipe Network Hydraulics

An Efficient Iterative Method for Looped Pipe Network Hydraulics

and accordingly volume of gas is decreased four times compared to volume of gas at normal (standard) conditions. But operate pressure for gas distribution network can be lower (this case is valid for network in paper of Brkić [3]). This is not typical for natural gas distributive networks. This was common practice in obsolete systems for distribution of city gas derived from coal [30]. So, flow in Renourad formula (1) adjusted for natural gas is usually expressed in normal (standard) conditions. Consequence is that if flows in previous paper of Brkić [3] are expressed in their real (compressed) values and if these real values are numerically equalized with values expressed for normal (standard) conditions, this means that operate pressure in gas network is normal (standard). Otherwise, velocities in previous paper of Brkić [3] have to be corrected. Velocities in previous paper of Brkić [3] are calculated to be comparable with the procedure shown in Manojlović et al [40] where calculation of gas distribution network in Serbian town Kragujevac is discussed. In Manojlović et al [40], flows are expressed in their real values and not for normal or standard conditions of pressure as common practice is or this network is calculated to work with lower pressure typical for gasses derived from coal. Second assumption can be rejected as less possible because in the part of Serbia south of rivers Sava and Danube where Kragujevac is situated, such gas was never used and especially not in 1990’s. Some comments about that issue was also shown in Brkić [5]. So, to avoid any further ambiguity, conclusion is that all flows previous paper of Brkić [3] are expressed in their real (compressed) values while operate pressure at the inputs of shown networks is normal (standard).

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Mine ventilation network optimization to reduce power consumption  with an improved pso algorithm

Mine ventilation network optimization to reduce power consumption with an improved pso algorithm

Underground mines are becoming deeper due to the depletion of shallower mineral mine ventilation network can save tremendous of electricity cost used by fans. This requires the ventilation system to be regulated so that the required airflow to the mine key areas are met with minimum power consumption. But mine internal coupled strongly. The air-flow of all the other branches flow is regulated. Such a problem becomes more complicated if multiple main fans are installed. The Hardy Cross method can in pipe network systems where the inputs and outputs are known with the optimum regulating scheme with iterative method such as Hardy Cross, because the inputs of the network systems are the regulating This paper established a mine ventilation PSO optimization algorithm to solve the model. By applying it to a typical mine ventilation network case, it is demonstrated that the proposed algorithm can reach the global optimal solution in shorter computational time. It is recommended to incorporate the algorithm to commercial ventilation network analysis software to assist with cost effective ventilation planning.

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A system design for distributed energy generation in low temperature district heating (LTDH) networks

A system design for distributed energy generation in low temperature district heating (LTDH) networks

This paper describes the initial phase of project SCENIC, achieving truly distributed generation within a heat network. The first of its kind, the system has a four pipe network configuration, consisting of a network flow loop to supply heat to homes, and a generation loop to collect energy from residential heating systems and supply it to a centralised thermal store. To achieve the design, IES-VE steady state heat load and dynamic building modelling have been used. A pre-insulated Rehau Rauthermex piping diameter was sized using flow rate calculations. Pipe diameter is reduced in line with distance from the central pump and associated pressure losses. The diameter ranges from 40 to 25mm, with a heat loss as low as 7.0 W/m. In addition, flow rates will fluctuate below a maximum of 1.99 l/s.

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Monte Carlo simulation for urban water supply infrastructure 
		availability

Monte Carlo simulation for urban water supply infrastructure availability

Monte Carlo simulation model can be used to investigate any complex system, failure patterns, and detailed aspects of component repair such as priorities and repair resource limitations. The operational states in which the system is found as a result of each failure or repair completion, are logged and used for determining a performance index of the system. Few researchers have used simulation methods for reliability assessment of water distribution networks [6, 12, 16]. This paper presents a simulation study of a real-life urban Water Distribution System (WDS) in India, in order to evaluate the performance of the water distribution system. The proposed simulation approach takes into account the random failure of multiple components in the pumping system as well as the water distribution pipe network. The remainder of the paper is organized as follows. A

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SOLVING ECONOMIC DISPATCH PROBLEM USING PARTICLE SWARM OPTIMIZATION BY AN 
EVOLUTIONARY TECHNIQUE FOR INITIALIZING PARTICLES

SOLVING ECONOMIC DISPATCH PROBLEM USING PARTICLE SWARM OPTIMIZATION BY AN EVOLUTIONARY TECHNIQUE FOR INITIALIZING PARTICLES

Optimization design of water supply pipe network is important with the development of economy and the increasingly fast urbanization process. Harmony search algorithm for the optimal design of water supply networks provides a better nonlinear optimization method. The improved strategy of the dynamic harmony memory size is proposed, through the optimization computation to water supply pipe network, compared with other algorithms, the improved HS algorithm in network optimization design problem has its superiority, its high speed, high efficiency, good convergence, can guarantee the stability of the global search optimization, and can provide the optimal design scheme.

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Design and Analysis of Water Hammer Effect in a Network of Pipelines

Design and Analysis of Water Hammer Effect in a Network of Pipelines

Abstract-There will be a chance for the destruction of the system due to transient if it is not provided with adequate protection devices. Generally, transient takes place when parameters involving in conventional flow are distorted with respect to the time. Rapid closing of valve in a pipe network will be resulting into hydraulic transient known as water hammer occurs due to sudden change in pressure and velocity of flow with respect to time. Due to impulsive action, pressure surges are induced in the system travel along the pipe network with the rapid fluid acceleration leading to the dramatic effects like pipe line failure, damage to the system etc. Considering the importance of hydraulic transient analysis, we design a system capable of verifying pipe network containing fluid flow.This paper demonstrates design of different pipe structures in pipe line network and analysis of various parameters like excess pressure distribution, velocity variations and water hammer amplitude with respect to time using COMSOL Multiphysics v 4.3. The magnitude of water transient in pipe line network at different pressure points has been discussed in detail.

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Markov and Neural Network Models for Prediction of Structural Deterioration of Stormwater Pipe Assets

Markov and Neural Network Models for Prediction of Structural Deterioration of Stormwater Pipe Assets

To answer the question of annual budget, the structural condition changes of pipe population obtained from the Markov model with transition probabilities estimated from the entire dataset is plotted against pipe age as shown in Fig. 2. This figure was constructed assuming that all pipes come from a homogenous population (i.e. effects of contributing factors were ignored). The figure shows an initial steep upwards slope for distribution curves of structural conditions 2 and 3 with a peak at the age of about 45 for condition grade 2. The proportions of conditions 1 and 3 continuously decreased and increased respectively over the years. If maintenance and rehabilitation (M&R) actions are not carried out until the age of 120 year, about 80% of pipes would be predicted to be in the structural condition 3. Furthermore, the age of 40 years can be seen as the critical time of the stormwater pipe network in this study, when the probability of pipes in condition 3 starts to exceed 0.6, although some pipes in reality are observed as still in good condition at the age of 100 or more. The value of 0.6 is selected because this value corresponds with the timing that the probability of pipes in condition 1 is well below both probabilities in condition 2 and 3 as can be seen in Fig. 2. This means that if maintenance is deferred, pipes at the age of 40 and older should be inspected. To select the candidate pipes for CCTV- inspection, the NNM can be used to predict the condition of each pipe because older pipes do not necessarily have poor condition.

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Design of Pipe Shoe Support for Horizontal Large Bore Lines

Design of Pipe Shoe Support for Horizontal Large Bore Lines

Since shoesplays a vitalrole in supporting the pipe network and to maintain its stability, itshould be designed in such a way that it can afford the Pipe dead weight load,the internal pressure of the pipe due to liquid that flow through the pipe, lateral Guide loads due to Operating conditions like thermal and occasional loads.Similarly Axial loads due to thermal, occasional and frictional effect.

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Design and Development of Optimal Loop
Water Distribution System

Design and Development of Optimal Loop Water Distribution System

With increasing population growth and industrial development, water flow rates and other hydraulic requirements associated with water distribution systems have been estimated to increase both national and local scale. Water shortage will cause inconvenience to people’s life and it will impact city function and industrial production. Hence to overcome this problem design and analysis of water distribution system is necessary to get optimal discharge. In this paper the optimization of water distribution network is discussed. An optimal model is developed which is based on the method of linear programming. In this model not only cost criteria of network but also energy consumption is to be considered. Computer program is developed i n visual basic for looped water distribution network using Hardy-cross method to minimize the time required for analysis and to make tedious work to easier. Result shows that software results were more accurate, time saving than manual results.

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Heat Pipe for Aerospace Applications—An Overview

Heat Pipe for Aerospace Applications—An Overview

pipe that includes Sintered metal powder, screen, and grooved wicks, which have a series of grooves parallel to the pipe axis. The performance of the heat pipes also depends upon selecting a container, a wick, and welding materials compatible with one another and with the working fluid of interest. Performance can be degraded and failures can occur in the container wall if any of these constituents are not compatible. For example, the consti- tuents can react chemically or set up a galvanic cell within the heat pipe. Additionally, the container material may be soluble in the working fluid or may catalyze the decomposition of the working fluid on reaching a par- ticular temperature limit of the working fluid. The reference [23] provides the most up-to-date information pre- sented in Table 1 concerning the compatibility of metals with the working fluids. High quality arterial grooved heat pipes are preferred for the thermal stabilization of the satellites. There are various configurations of heat pipe available in the market for variety of applications [24] Most of the heat pipes are generally circular cylind- ers. Other shapes, such as rectangular (vapor chamber), conical (rotating heat pipes), triangular (micro heat pipes) and nose cap geometries (leading edge cooling) are also studied.

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Guidelines For Construction of Pipe Distribution Network (PDN) For Irrigation

Guidelines For Construction of Pipe Distribution Network (PDN) For Irrigation

11. CONCLUSION AND RECOMMENDATIONS Considering the scarcity of water, PDN system is recommended for irrigation in command area. PDN system saves water over conventional CDN system and should be preferred where land cost is comparatively high and farmers are unwilling to handover their valuable land. The pipe line distribution system would be more suitable for implementation of modern techniques like sprinkler and drip irrigation etc. The planning and design of PDN should be carefully done so that maximum benefits of the system can be utilized.

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Pressure Surge Dependence on Valve  Operations in a Pipeline Loading System

Pressure Surge Dependence on Valve Operations in a Pipeline Loading System

This paper discusses the influence of valve operations on pressure surge in a pipeline. The valve is a protective type which remains open in a pipeline loading system during normal operation but shut down the system when there is an emergency such as storm. The data for the study were ob- tained from measurements at Agbada 1 flow station as well as log sheets. Also, calculations were made using existing and derived formulas to obtain the values of Crude Oil and Pipe parameters that could not be measured directly or derived from data or log sheets. Surge analysis was carried out on the pipeline system to ascertain changes in pressure and flow rates along the pipeline fol- lowing valve shut down at any time using developed pressure and flow equations. The results of the simulation analysis showed remarkable changes in the fluid pressure and flow rates along the pipe on shut down at any time. The pipeline recorded the highest pressure of 37.4 bar against ini- tial pressure of 25 bar at length 6000 m in 1.5 second valve closure. There is also remarkable pressure drop along the pipe capable of reducing the crude oil pressure below its vapour pressure. The flow is turbulent even before valve operation with Reynolds number as high as 57024.53. The model equations compute changes in pressure and flow rates at different points in a pipeline in- stalled with emergency-relief coupling valve. This enables point of extreme and low pressure to be detected accurately in a pipeline which guides the engineer while positioning surge suppression devices which cushion the effects of pressure surge in any pipeline.

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Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment

Spatial variability of herbicide mobilisation and transport at catchment scale: insights from a field experiment

is moderate with altitudes ranging from 423 to 477 m a.s.l. and an average slope of 4.3 ◦ (min = 0 ◦ , max = 42 ◦ , based on 2 × 2 m digital elevation model (DEM), absolute accu- racy: σ = 0.5 m, resolution = 1 cm, Swisstopo, 2003). The twenty-year mean annual precipitation at the closest perma- nent measurement station (Schaffhausen, 11 km north of the catchment) is 883 mm (Meteoschweiz, 2009). The soils de- veloped on moraine material with a thickness of around ten metres, which is underlain with S¨ußwassermolasse (fresh- water molasse) (Swisstopo, 2007). Soils in the centre of the catchment are poorly drained gleysoils. Well drained cam- bisols and eroded regosols are located in the higher parts of the catchment (FAL, 1997, see Fig. 1). Soil thickness (sur- face to C horizon) varies between 30 cm at the eroded lo- cations and more than 2 m in the depressions and near the stream. The catchment is heavily modified by human activ- ities; it encompasses a road network with a total length of 11.5 km (approximately 3 km are paved and drained, the rest is unpaved and not drained). The dominant land use is crop production (75 % of the area), mainly corn, sugar beet, win- ter wheat and rape seed. Around 13 % of the catchment is covered by forest, and a small settlement area is located in the southeast of the catchment. Three farms lie at least partly within the catchment (see Fig. 1). 47 % of the agricultural land is drained by tile drains with a total length of over 21 km (Gemeinde Ossingen, 1995, the open stream has a length of

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Robust optimization methodologies for water supply systems design

Robust optimization methodologies for water supply systems design

To obtain high robustness solutions WSSs must be designed to cope with extreme operating conditions during their life cycle. The uncertainty related to future operating conditions should be taken into account early in the design stage. This work has presented a robust optimization model to help deci- sion makers attain a good trade-o ff between reliability and cost. The performance of this method was illustrated by means of two case studies. The reliability of the water supply systems was ensured by two di ff erent strategies: 1st – design- ing the system to cope with the extreme operating conditions by increasing the pipe diameters; 2nd – designing the system for normal operating conditions and introducing a pumping station to deal with the extreme operating conditions.

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Experimental and Comparison Study of Heat Transfer Characteristics of Wickless Heat Pipes by using Various Heat Inputs

Experimental and Comparison Study of Heat Transfer Characteristics of Wickless Heat Pipes by using Various Heat Inputs

The heat pipe generally consists of three sections namely, evaporating section, adiabatic section and condensation section. There are four RTDs in each pipes. One in the evaporating section, one in the condensation section and two in the adiabatic section. Thus the temperatures in the various sections of the pipes can be determined. In the evaporating section, band heaters are used to convert the working fluids into vapour. In the condensation section, water flow is used as the method to condensate the vapour into liquid. The rate of flow of water in the cooling duct is calculated. Also, the temperatures of the coolant at entry and exit are found out to determine the amount of heat transferred from the pipe to the cooling duct.

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Design and Analysis of Pipe Rack System using STAAD PRO V8i Software

Design and Analysis of Pipe Rack System using STAAD PRO V8i Software

7) Longitudinal Pipe Friction Forces (PFL): A longitudinal horizontal force due to pipe friction equal to 10% of the pipe operating weight (empty pipes + pipe contents) shall be applied on each pipe supporting beam of the pipe rack. For small bore lines (less than 12 inch dia)above loads shall be taken as uniformly distributed. The friction loads shall be considered to be acting at the respective pipe locations on the beam.

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A New Approach for Estimating Free Point in Fishing of Stuck Pipe using Artificial Neural Network

A New Approach for Estimating Free Point in Fishing of Stuck Pipe using Artificial Neural Network

In this study, an attempt is made to estimate the free point in stuck pipe cases using the drilling data and artificial neural network approach. For this purpose, drilling data such as mud properties, pipe rotation, rate of penetration, and some other parameters are required. In this study, artificial neural networks (ANNs) model using field data from more than 40 wells was employed, and results were compared to field results. ANN model was constructed with a supervised learning algorithm and feed forward back propagation learning rule is used for training the network. The statistical error analysis results obtained by the models and acceptable values for correlation coefficient indicate that ANN model is successful in free point prediction.

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Effect of Pump Inertia & Valve Closure time on the Transient Flow Condition of a Water Supply Network: A Case Study

Effect of Pump Inertia & Valve Closure time on the Transient Flow Condition of a Water Supply Network: A Case Study

Many researchers contributed in the study of transient flow conditions, due to valve closure and inertia of the pump. Mosab[9] studied the effect of pump inertia and valve closure time and found that the stepwise valve closure can reduce transients significantly than the linear valve closure operation. A pump with a high inertia can also reduce transients significantly. It is found that network junctions, bifurcations flow passages are affected by the passage of the reflection and refraction of waves in the water hammer. Rao[11] used the simulation software to study the Increased pressure in the pipes and presented in the manual calculation of the parameters . The results are compared with the available experimental data.

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