scholarly journals A cost model with several hydraulic constraints for optimizing in practice a trapezoidal cross section

2017 ◽  
Vol 19 (3) ◽  
pp. 456-468
Author(s):  
Kiyoumars Roushangar ◽  
Mohammad Taghi Alami ◽  
Vahid Nourani ◽  
Aida Nouri
Keyword(s):  
Froude Number ◽  
Cross Section ◽  
Cost Model ◽  
Channel Cross Section ◽  
Total Cost ◽  
Trapezoidal Channel ◽  
Side Slope ◽  
Bottom Width ◽  
The Cost ◽  
Channel Structures

Open channel structures are essential to infrastructure networks and expensive to manufacture. Optimizing the design of channel structures can reduce the total cost of a channel's length, including costs of lining, earthwork, and water lost through seepage and evaporation. The present research aims to present various optimization models towards the design of trapezoidal channel cross section. First, a general resistance equation was applied as a constraint. Next, a genetic algorithm (GA) was used to determine the optimal geometry of a trapezoidal channel section based on several parameters, i.e., depth, bottom width, and side slope. Eight different models were proposed and evaluated with no other constraint besides financial cost as well as with a normal depth, flow velocity, Froude number, top width, and by ignoring the cost of seepage. Numerical outcomes obtained by the GA are compared to previous studies in order to determine the most efficient model. Results from a single application indicate that the restriction of depth, velocity, and Froude number can increase the total cost, while restriction of the top width can decrease the cost of the construction. Also, the solution for various example problems incorporating different discharge values and bed slopes caused increase and decrease in cost, respectively.

Optimization of Leased Equipment Maintenance Policy Based on History Failure Data

2021 ◽  
pp. 2150030
Author(s):  
Ke Dong ◽  
Kehong Chen
Keyword(s):  
Power Law ◽  
Cost Model ◽  
Maintenance Strategy ◽  
Maintenance Policy ◽  
Power Law Process ◽  
Total Cost ◽  
Cost Rate ◽  
Failure Data ◽  
Expected Total Cost ◽  
The Cost

We propose a maintenance policy for new equipment on a repair-refund maintenance strategy in this paper and derive the optimal lease period from the lessor’s perspective based on independent and identical distribution of historical failure data which obey power law process. The cost model of a full refund and a proportional refund is studied, and the corresponding optimal leasing period is determined by reducing the expected total cost rate to the largest extent. We use a numerical example to illustrate the proposed cost model and analyze the sensitivity of related parameters. Furthermore, we show that the proportional refund policy is preferable than a full refund to the lessor. Finally, according to the simulation outcome, the proposed methods are effective and instructions for lessor in regard to equipment lease are provided.

scholarly journals Analytical Models for Optimal Design of a Trapezoidal Composite Channel Cross-Section

2021 ◽  
Vol 31 (1) ◽  
pp. 118-138
Author(s):  
Somayyeh Pourbakhshian ◽  
Majid Pouraminian
Keyword(s):  
Optimal Design ◽  
Cost Function ◽  
Objective Function ◽  
Cross Section ◽  
Analytical Models ◽  
Channel Cross Section ◽  
Roughness Coefficient ◽  
Composite Channel ◽  
Design Variables ◽  
The Cost

Abstract In this paper, several analytical models are presented for the optimal design of a trapezoidal composite channel cross-section. The objective function is the cost function per unit length of the channel, which includes the excavation and lining costs. To define the system, design variables including channel depth, channel width, side slopes, freeboard, and roughness coefficients were used. The constraints include Manning’s equation, flow velocity, Froude number, and water surface width. The Simultaneous Perturbation Stochastic Approximation (SPSA) algorithm was used to solve the optimization problem. The results are presented in three parts; in the first part, the optimal values of the design variables and the objective function are presented in different discharges. In the second part, the relationship between cost and design variables in different discharges is presented in the form of conceptual and analytical models and mathematical functions. Finally, in the third part, the changes in the design variables and cost function are presented as a graph based on the discharge variations. Results indicate that the cost increases with increasing water depth, left side slope, equivalent roughness coefficient, and freeboard.

Optimal lined channel design

2006 ◽  
Vol 33 (5) ◽  
pp. 535-545 ◽  
Author(s):  
Bülent Aksoy ◽  
A Burcu Altan-Sakarya
Keyword(s):  
Open Channel ◽  
Unit Cost ◽  
Ground Surface ◽  
Minimum Cost ◽  
Channel Design ◽  
Minimum Area ◽  
Side Slope ◽  
Bottom Width ◽  
The Cost ◽  
Open Channel Design

The optimum values of the section variables (side slope, bottom width, flow depth, and radius) for triangular, rectangular, trapezoidal, and circular channels are computed by minimizing the cost of the channel section. Manning's uniform flow formula is treated as the constraint of the optimization model. The cost function is arranged to include the cost of lining, the cost of earthwork, and the increment in the cost of earthwork with depth below the ground surface. The optimum values of section variables are expressed as explicit functions of unit cost terms. Unique values of optimum section variables are obtained for the case of minimum area or minimum wetted perimeter problems. Key words: open channel design, optimization, minimum cost, best hydraulic section.

ON OPTIMUM MODULE SIZE FOR SOFTWARE INSPECTIONS

2007 ◽  
Vol 14 (03) ◽  
pp. 283-295 ◽  
Author(s):  
PANKAJ JALOTE ◽  
ASHOK K. MITTAL ◽  
RAM GOPAL PRAJAPAT
Keyword(s):  
Software Development ◽  
Design Of Experiments ◽  
Control Parameter ◽  
Cost Model ◽  
Cost Effective ◽  
Total Cost ◽  
Software Inspections ◽  
Inspection Process ◽  
Module Size ◽  
The Cost

Inspection is widely believed to be one of the most cost-effective methods for detection of defects in the work products produced during software development. However, the inspection process, by its very nature, is labor intensive and for delivering value, they have to be properly executed and controlled. While controlling the inspection process, the inspection module size is a key control parameter. Larger module size can lead to an increased leakage of defects which increases the cost since rework in the subsequent phases is more expensive. Small module size reduces the defect leakage but increases the number of inspections. In this paper, we formulate a cost model for an inspection process using which the total cost can be minimized. We then use the technique of Design of Experiments to study how the optimum module size varies with some of the key parameters of the inspection process, and determine the optimum module size for different situations.

Optimizing channel cross-section based on cat swarm optimization

2015 ◽  
Vol 16 (1) ◽  
pp. 219-228 ◽  
Author(s):  
Dong Liu ◽  
Yuxiang Hu ◽  
Qiang Fu ◽  
Khan M. Imran
Keyword(s):  
Cross Section ◽  
Optimization Technique ◽  
Land Acquisition ◽  
Open Channels ◽  
Channel Cross Section ◽  
Concrete Lining ◽  
Swarm Optimization ◽  
Channel Section ◽  
Cat Swarm Optimization ◽  
The Cost

Optimal design of channel cross-section is an important task in the hydraulic design of open channels. The traditional methods and models which neglect the frost heave are trial procedures and may result in failure of channels in design of irrigation channels. To improve the total cost, reliability and effectiveness, the model which is used in this study, is not only minimizing the cost of land acquisition but also the cost of concrete lining considering cost as the objective function. The constrained optimization model which considers values of thickness of channel concrete slab constraint simultaneously along with the objective of minimization of cost is propounded and solved using a recent global optimization technique, namely cat swarm optimization (CSO). The optimized channel section not only satisfies the optimal hydraulic cross-section but guarantees the safety and stability of the side walls so that both the amount of the concrete lining and the land acquisition are optimized. Finally, we take a main channel of Qinghe Irrigated Area of Farm 853 in Heilongjiang Province as a study area. The results obtained using the CSO approach are satisfaction and the method can be used for reliable design of artificial open channels. Furthermore, we compare the CSO algorithm with a genetic algorithm (GA) and the particle swarm optimization (PSO) to verify the effectiveness of the cat swarm algorithm in the channel section optimization.

scholarly journals Life Cycle Costing Model for the Membrane System

2019 ◽  
Vol 4 (1) ◽  
pp. 64-67
Author(s):  
Nur Syamimi Jiran ◽  
Muhamad Zameri Mat Saman ◽  
Noordin Mohd. Yusof
Keyword(s):  
Cost Estimation ◽  
Early Stage ◽  
Cost Model ◽  
New Technology ◽  
Membrane System ◽  
Economic Indicator ◽  
Activity Based Costing ◽  
Product Cost ◽  
Total Cost ◽  
The Cost

Computerized cost estimation though cost model help user to estimating product cost since the early stage of product development. Total product cost is an economic indicator that a sustainable product promotes a good impact on the environment but also contribute a profit increased to the organization. In addition, the cost model could be a decision-making tool for the organization in selecting alternatives to replace the older system in term of financial and other benefits offered by the new technology. The proposed cost model helps membrane user to select the lower membrane system’s cost during its complete lifespan and it helps management to rearrange the production line and filtering system in reducing the total cost. Activity-based costing (ABC) useful in estimating the overhead cost, the total cost of the membrane system and also other useful information in improving the whole membrane system.

scholarly journals The cost effectiveness of early management of acute appendicitis underlies the importance of curative surgical services to a primary healthcare programme

2013 ◽  
Vol 95 (4) ◽  
pp. 280-284 ◽  
Author(s):  
V Kong ◽  
C Aldous ◽  
J Handley ◽  
D Clarke
Keyword(s):  
Intensive Care ◽  
Acute Appendicitis ◽  
Primary Healthcare ◽  
Cost Model ◽  
Abdominal Sepsis ◽  
Surgical Service ◽  
Intensive Care Admission ◽  
Total Cost ◽  
Uncomplicated Appendicitis ◽  
The Cost

Introduction Appendicitis in the developing world is a cause of significant preventable morbidity. This prospective study from a regional hospital in South Africa constructs a robust cost model that demonstrates the cost effectiveness of an efficient curative surgical service in a primary healthcare-orientated system. Methods A prospective audit of all patients with acute appendicitis admitted to Edendale Hospital was undertaken from September 2010 to September 2011. A microcosting approach was used to construct a cost model based on the estimated cost of operative and perioperative interventions together with the associated hospital stay. For cost analysis, patients were divided into the following cohorts: uncomplicated appendicitis, complicated appendicitis with localised intra-abdominal sepsis, complicated appendicitis with generalised intra-abdominal sepsis, with and without intensive care unit admission. Results Two hundred patients were operated on for acute appendicitis. Of these, 36% (71/200) had uncomplicated appendicitis and 57% (114/200) had perforation. Pathologies other than appendicitis were present in 8% (15/200) and these patients were excluded. Of the perforated appendices, 45% (51/114) had intra-abdominal contamination that was localised while 55% (63/114) generalised sepsis. The mean cost for each patient was: 6,578 ZAR (£566) for uncomplicated appendicitis; 14,791 ZAR (£1,272) for perforation with localised intra-abdominal sepsis and 34,773 ZAR (£2,990) for perforation with generalised intra-abdominal sepsis without intensive care admission. With intensive care admission it was 77,816 ZAR (£6,692). The total cost of managing acute appendicitis was 4,272,871 ZAR (£367,467). Almost 90% of this total cost was owing to advanced disease with abdominal sepsis and therefore potentially preventable. Conclusions Early uncomplicated appendicitis treated appropriately carries little morbidity and is relatively inexpensive to treat. As the pathology progresses, the cost rises exponentially. An efficient curative surgical service must be regarded as a cost effective component of a primary healthcare orientated system.

Design for manufacture: Cost-estimating model for randomly oriented strand advanced composite aerospace parts

2017 ◽  
Vol 233 (6) ◽  
pp. 1241-1251
Author(s):  
Mohamed El Wazziki ◽  
Anh Dung Ngo
Keyword(s):  
Scaling Laws ◽  
Cost Model ◽  
Linear Equations ◽  
Thermoplastic Composites ◽  
Manufacturing Cost ◽  
Cost Estimating ◽  
Total Cost ◽  
Excel Spreadsheet ◽  
Cycle Times ◽  
The Cost

This work aimed at developing a parametric cost-estimating model based on physical laws for making three categories of thermoplastic composites structural aerospace parts from discontinuous prepreg randomly oriented strands. The proposed cost model will use Microsoft Excel spreadsheet developed in house which imputes all industrial and academic data for calculating costs elements such as material, labour, energy, machinery, building costs and costs of working capital, overheads and then the total cost per part. This research study focused, on one hand, at estimating the heating costs for experimental and virtual parts by changing the volume and keeping the same process cycle times. The heating power was determined by simulating the process thermal diagram numerically using finite elements COMSOL software and validated by experimental data. On the other hand, the tooling costs were estimated by DFMA software for experimental and virtual moulds by changing the projected area. Then, the heating energy and tooling costs sizing scaling laws were established under linear equation forms limited to the size of platens areas. These linear equations were inputted in an Excel spreadsheet to calculate the cost of new parts, which have not been made yet. The variation of the total cost with the size and the complexity of the part were investigated. The results showed that the calculated heating energy costs of the three experimental randomly oriented strand parts were different due to different geometries of the heating platens and the moulds. For the mould cost, the more complex the form was the higher the cost. For total cost, it was also demonstrated that the manufacturing cost of L-bracket part was higher than that of flat plate and T-shape part due to higher process cycle time.

scholarly journals Numerical and Theoretical Study of Performance and Mechanical Behavior of PEM-FC Using Innovative Channel Geometrical Configurations

2021 ◽  
Vol 11 (12) ◽  
pp. 5597
Author(s):  
Hussein A. Z. AL-bonsrulah ◽  
Mohammed J. Alshukri ◽  
Ammar I. Alsabery ◽  
Ishak Hashim
Keyword(s):  
Fuel Cell ◽  
Cross Section ◽  
Rectangular Channel ◽  
Compressive Load ◽  
Proton Exchange ◽  
Channel Cross Section ◽  
Channel Height ◽  
Cross Sectional ◽  
Triangular Channel ◽  
Higher Power

Proton exchange membrane fuel cell (PEM-FC) aggregation pressure causes extensive strains in cell segments. The compression of each segment takes place through the cell modeling method. In addition, a very heterogeneous compressive load is produced because of the recurrent channel rib design of the dipole plates, so that while high strains are provided below the rib, the domain continues in its initial uncompressed case under the ducts approximate to it. This leads to significant spatial variations in thermal and electrical connections and contact resistances (both in rib–GDL and membrane–GDL interfaces). Variations in heat, charge, and mass transfer rates within the GDL can affect the performance of the fuel cell (FC) and its lifetime. In this paper, two scenarios are considered to verify the performance and lifetime of the PEM-FC using different innovative channel geometries. The first scenario is conducted by adopting a constant channel height (H = 1 mm) for all the differently shaped channels studied. In contrast, the second scenario is conducted by taking a constant channel cross-sectional area (A = 1 mm2) for all the studied channels. Therefore, a computational fluid dynamics model (CFD) for a PEM fuel cell is formed through the assembly of FC to simulate the pressure variations inside it. The simulation results showed that a triangular cross-section channel provided the uniformity of the pressure distribution, with lower deformations and lower mechanical stresses. The analysis helped gain insights into the physical mechanisms that lead to the FC’s durability and identify important parameters under different conditions. The model shows that it can assume the intracellular pressure configuration toward durability and appearance containing limited experimental data. The results also proved that the better cell voltage occurs in the case of the rectangular channel cross-section, and therefore, higher power from the FC, although its durability is much lower compared to the durability of the triangular channel. The results also showed that the rectangular channel cross-section gave higher cell voltages, and therefore, higher power (0.63 W) from the fuel cell, although its durability is much lower compared to the durability of the triangular channel. Therefore, the triangular channel gives better performance compared to other innovative channels.

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