Operating Cost Model Research Articles

Development of a techno-economic simulation tool for an improved mineral processing plant design

Simulation is widely used in design and optimization of mineral processing circuits to answer “what if” questions regarding the employment of different equipment and configurations. The questions could be answered better if the long-term economic impacts of different circuits are readily estimated within the designing stage, considering both economic and technical constraints and criteria. This paper introduces a new open source user-friendly techno-economic simulator developed in Matlab/Simulink that joins multivariate capital and operating cost models to technical models of equipment and estimates some economic analytical indicators of the circuits such as Net Present Value simultaneously when the circuit is being designed. The proposed approach enables the designer to easily consider the technical and economic interactions and tradeoffs. As a case study, the long-term economic impact of selecting different numbers of leaching tanks is investigated and it is shown that even the optimum number of tanks could be a function of discount rate of the project.

Manufacturing enterprise’s logistics operational cost simulation and optimization from the perspective of inter-firm network

Purpose: By studying the case of a Changsha engineering machinery manufacturing firm, this paper aims to find out the optimization tactics to reduce enterprise’s logistics operational cost. Design/methodology/approach: This paper builds the structure model of manufacturing enterprise’s logistics operational costs from the perspective of inter-firm network and simulates the model based on system dynamics. Findings: It concludes that applying system dynamics in the research of manufacturing enterprise’s logistics cost control can better reflect the relationship of factors in the system. And the case firm can optimize the logistics costs by implement joint distribution. Research limitations/implications: This study still lacks comprehensive consideration about the variables quantities and quantitative of the control factors. In the future, we should strengthen the collection of data and information about the engineering manufacturing firms and improve the logistics operational cost model. Practical implications: This study puts forward some optimization tactics to reduce enterprise’s logistics operational cost. And it is of great significance for enterprise’s supply chain management optimization and logistics cost control. Originality/value: Differing from the existing literatures, this paper builds the structure model of manufacturing enterprise’s logistics operational costs from the perspective of inter-firm network and simulates the model based on system dynamics.

Triple Feed-forward APIOBPCS Based Resilience and Operational Costs Assessment of Supply Chain

In order to trade off between supply chain resilience and operational cost, a sort of triple feed-forward automatic pipeline, inventory and order-based production control system(TFF-APIOBPCS) is presented. A first order differential feedforward unit, introduced to production control model APIOBPCS, enables the model to mitigate the impact of fluctuations in demand on actual inventory. Aiming at different pole distribution of the production control system, analysis of the relationship between the parameters of first order differential feedforward and resilience are conducted under zero steady-state error. Supply chain operational cost model is constructed by comprehensive consideration of inventory cost and production regulation cost. Supply chain system simulations with a unit step signal and a stochastic signal as the customer demand evaluate the effect of the first order differential feedforward parameters on supply chain resilience and operational cost, and reveal the validity of TFF-APIOBPCS. The results show that, for different degree of volatility of demand, setting the parameters of first order differential feedforward unit reasonably, can obtain better equilibrium of elasticity and operation cost.

AVALIAÇÃO DE CUSTOS DE DOIS MODELOS DE <i>HARVESTER</i> NO CORTE DE EUCALIPTO

http://dx.doi.org/10.5902/1980509815733O presente estudo teve o objetivo de realizar a avaliação de custos de dois modelos de harvester, na colheita de madeira de eucalipto. A pesquisa avaliou a derrubada e o processamento da árvore, com idade de 6 anos, no sistema de toras curtas, para dois modelos de harvester, em áreas localizadas nos municípios de Conceição da Barra – ES e Caravelas – BA. Avaliaram-se dois modelos de harvester, PC-228 SHO e PC-200 LC, da marca Komatsu. As informações foram coletadas durante um período de 6 meses, que compreende os meses de março a agosto de 2010, pelo método de censo. Calcularam-se os custos operacionais dos dois modelos de harvester, pelo método contábil, o qual utiliza valores estimados em reais. Realizou-se ainda a análise de sensibilidade de custos para os elementos que mais contribuem com o custo final. Obteve-se o custo operacional para os modelos PC 200 e PC 228 de R$ 156,95 e R$ 168,84 por hora efetiva, respectivamente. Em relação aos custos operacionais totais, os custos mais significativos foram: combustível, manutenção e reparos e depreciação, com 24,41%, 22,39% e 19,08%, respectivamente. Na análise de sensibilidade, simulando uma situação em que a empresa consiga uma economia real de 10% em cada um desses itens, a mesma poderá obter uma redução no custo de produção em 7%, para as duas máquinas avaliadas.

A proposal of the military operation cost model

The decision-making process requires necessary consideration of the costs of execution, expressed by the cost price. The cost price is always a limiting factor, but may also be a crucial one in the decision-making. In addition to the necessity of making an optimal decision on the use of forces in an operation for the purpose of achieving the desired final situation, it is very important to achieve the objective at as little cost as possible. Limited and generally insufficient resources represent a factor that imposes a constant need for cost-effective, rational and efficient use of the available resources. The paper presents a methodological approach to the estimate of a military operation cost price. Operations of the Armed Forces are directed at the military-strategic level, and planned and executed at the operational and tactical level. The military-strategic level considers military engagement in a campaign, which includes several operations for the purpose of reaching the identified military-strategic objectives and achieving the desired final situation. Considerations of the military involvement and the planning of military operations require a comprehensive analysis of all factors that affect the decision making. One of the factors to which special attention is addressed in the process of the operational planning is the operation cost. The model of operation cost estimate greatly helps reach a realistic operation cost.

Capturing the impact of fuel price on jet aircraft operating costs with Leontief technology and econometric models

Investigation of the airline response to a fuel price increase is in effect an investigation of the role of variable interactions in aircraft cost models. We examine the impact of fuel price on aircraft costs and airline operational strategies by developing two classes of operating cost models for jet aircraft and comparing the results. The translog operating cost model is a flexible functional form that provides a detailed representation of the empirical relationship between fuel cost and operating cost, allowing for substitution, scale, aircraft age, and variable interactions to be captured. The simpler Leontief model assumes that inputs of a cost model must be used in fixed proportions regardless of their prices. While it does not capture variable interactions, the Leontief model is more transparent, requires fewer inputs, and allows the contribution of a single factor, such as fuel price, to operating cost to be more easily isolated. An analysis of the translog operating cost model reveals that as fuel price increases, airlines will take steps to use fuel more efficiently by leveraging other inputs; a comparison of the translog and the Leontief technology models, however, show that the potential for this supplier input substitution for fuel is rather modest. By building the two operating cost models and comparing their predictions, we illustrate a method to determine the prediction potential of a Leontief technology model and assess the importance of input substitution at the vehicle level.

Study of the Knowledge–Based Integrated Equipment Management System for Process Enterprise

Though analyzing the characters of the equipment management for process enterprise, there is a knowledge–based integrated equipment management system using knowledge management in order to maximize benefit, which emphasizes the technical reliability, enterprise capability balance and consists of equipment optimized control model, equipment operating cost model, equipment reliability evaluation model, equipment fault diagnosis model and equipment renovation decision support model, etc. The knowledge acquisition and representation model is aim to realize the decision-making flow of the process enterprise. A typical example is also presented to demonstrate the application of the integrated knowledge-based equipment management system.

Optimal Intercity Transportation Services With Heterogeneous Demand and Variable Fuel Price

Optimal Intercity Transportation Services With Heterogeneous Demand and Variable Fuel Price

Operating costs for reducing total emission loads of key pollutants in municipal wastewater treatment plants in China

Total emission load reduction of COD, NH(4)-N, TN, and TP is the key measure in controlling water pollution and eutrophication. Municipal wastewater treatment plants (MWWTPs) are major contributors in lowering energy consumption and reducing pollutant discharge. The flow-based operating costs have not been directly established to relate to costs of pollutant reduction based on an investigation of 11 MWWTPs in China. However, energy consumption to eliminate one kilogram of COD or NH(4)-N was observed to decrease when the total reduced pollutants is increased. Additional energy consumption required to remove nitrogen and phosphorus is allotted for mixers and internal return pumps. Major factors for operating costs include influent and effluent concentration, design capacity, and flow loading rate. Therefore, an operating cost model for the total emission load reduction of COD, NH(4)-N, TN, and TP was developed based on energy consumption and the above mentioned major factors. Using this model to calculate the operating costs for MWWTPs would facilitate more reduction of key pollutants than the flow-based method.

Selection and maintenance of mine haul road wearing course materials

The drive for greater cost efficiencies in surface mining has led to the development of very large off highway trucks currently capable of hauling payloads in excess of 290 tons on mine haul road networks that have historically been designed empirically, relying heavily on local experience. With the trend in increasing truck size, haul road performance has become unpredictable, difficult to manage and costs of both maintaining the road and operating the truck have also increased prohibitively. Most surface mine operators agree that good roads are desirable, but find it difficult to translate this requirement into an effective and responsive road maintenance management system (MMS). The aim of the present paper is to present an overview of the wearing course material selection for mine haul road applications and to recommend appropriate wearing course material selection guidelines. Using the material performance models established, the paper then describes the development of a haul road MMS utilising mine haul truck operating cost models to derive an optimal frequency of road maintenance. Finally, a typical application is presented which illustrates the potential of the technique to manage maintenance as and where needed with resultant reduction in total road user costs and an improvement in service provided for the road user.

6.1.1 The Application of Architecture Frameworks to Modelling Exploration Operations Costs

AbstractDevelopments in architectural frameworks and system‐of‐systems thinking have provided useful constructs for systems engineering. DoDAF concepts, language, and formalisms, in particular, provide a natural way of conceptualizing an operations cost model applicable to NASA's space exploration vision. Not all DoDAF products have meaning or apply to a DoDAF‐inspired operations cost model, but this paper describes how such DoDAF concepts as nodes, systems, and operational activities relate to the development of a model to estimate exploration operations costs. The paper discusses the specific implementation to the Mission Operations Directorate (MOD) operational functions/activities currently being developed and presents an overview of how this powerful representation can apply to robotic space missions as well.

Design and analysis of production control scheme for Kanban-based JIT environment

This paper aims at designing production control scheme for Kanban-based just-in-time (JIT) environment. Synchronization mechanism for a single-stage single-product Kanban-controlled production line is developed, in such a way that yields a feasible operating cost as well as a feasible average of work-in-progress (WIP). The Kanban production line is formulated as ( M / M / s : GD / ∞ / ∞ ) queuing model. A new approach for analyzing the queue model is discussed. An operating cost model is then developed to determine the unknown parameters of the system. Numerical examples are used to demonstrate the computations of different system parameters. Avenue for future research is also indicated.

INTEGRATED ZONAL IMPACT ANALYSIS SYSTEM: AN INITIAL EFFORT OF PLANNING SUPPORT SYSTEM IN DEVELOPING COUNTRIES

Abstract: To manage complex urbanizations, various advanced planning techniques have been developed. A last effort is the planning supporting system (PSS). This study intends to develop Integrated Zonal Impact Analysis (IZIA) System in Bangkapi District, Bangkok, by integrating land-use databases, transportation models, travel time and vehicle operating cost models, noise and air pollution models. Three unique characteristics are established: the zonal impact analysis framework, the impact interrelations in communities’ viewpoints, and the community involvements in mitigating impacts. The system consists of four functions: problem and alternative identifications, impact assessments, impact integrations under public preferences, and information displays. As the results, most stakeholders prioritized pollutions (0.64) higher than travel costs (0.34). Therefore, planners should seriously consider the pollution problems. With the minimum impact costs, a shopping center project should be allocated into the radial network center. For two projects, they should be implemented beside the expressways. The proposed IZIA system was a successful preliminary application.

Productivity and Cost of Mechanized Whole-Tree Harvesting of Fast-Growing Eucalypt Stands

The performance of alternative equipment for the whole-tree harvesting of eucalypt stands was evaluated, using data from five different commercial operations. The study covered three machines for felling and bunching, two for extraction (skidding), and two for combined delimbing, debarking and chipping. Productivity and operating cost models were evaluated for each of the machines, in order to estimate the net harvesting costs under varying forest stand and site conditions. It was found that under easy terrain conditions (flat terrain, dry ground), trees should be felled by threewheeled feller-bunchers and extracted by front-end loaders, as this combination had the lowest harvesting costs. Due to mobility limitations, this equipment may have to be replaced by tracked feller-bunchers and conventional skidders in steep terrain and/or soft ground. It was estimated that the cost of using the wheeled feller-buncher and the front-end loader system ranged between 16–22$ per oven-dry-ton (odt), depending on tree size. If difficult terrain imposes a shift towards the second, more expensive combination, harvesting cost will increase by about 30% and may exceed 25 $/odt for an average tree weight less than 0.1 odt. Unit costs are inflated by 30% if the hog fuel is considered a by-product and the harvesting cost is charged entirely on the clean chip.

Cost-optimal calculation for ice-storage systems using neural network

Based on the eminent characteristics of the ice-storage systems, which can shift cooling electrical demand from peak time to off peak time, this paper describes the ice storage air-conditioning system that is now used much frequently. The authors develop the operating cost model by simplification and introduce a neural network model and try to solve the optimal cost problem of operation by using this neural network model. In calculation, any trajectory of the neural network converges to its solution in finite time, which is consistent with result by simplex method. Comparing with different methods, the neural network is more effective, which can be alternative to simplex method in calculating the optimal cost model for ice storage air-conditioning systems.

Laddermill, a novel concept to exploit the energy in the airspace

Abstract A very significant amount of wind energy is contained in the movements of air at high altitudes. A particular invention (Laddermill Patent Ned. 1004508. Nov. 1996 applications Europe and USA), named “laddermill”, is described that allows exploiting this energy using the winds up to possibly the tropopause. A “laddermill” is a self-supporting system that consists of an endless cable connected to a series of high-lifting wings or kites moving up in a linear fashion, combined with a series of low-lifting wings or kites going down. The cable drives an energy generator placed on the ground. Dutch measured wind statistics are presented that show the immense power source at high altitudes. Some general physical considerations are given for the laddermill. Three simulation programmes were developed independently by different institutions. The results give a good consistency of the laddermill shape and power production. Design solutions are indicated for the wing attitude control and stability and a concept for the ground station is presented providing wing and cable handling. Adaptation to weather is given by flexible retrieval and deployment capability. Comparisons are shown with existing wind turbines. An operational model and related cost model have been made that include an operation strategy that optimises the economical effectiveness of the wings, cable and ground station. This operational model has been applied to the actual wind measurements over a period of 10 years. The results show, in comparison to the existing horizontal axes wind turbines, (i) a potential for significantly larger amount of wind energy production and (ii) an indication that this can be done at significantly lower cost. The public acceptance has been assessed, resulting in a positive perception of elegance of the low speed and silent movements combined with the excitement from reaching impressive altitudes. Safety and potential aviation interference are also addressed.

Using new packages for modelling, equation oriented simulation and optimization of a cogeneration plant

The development and testing of an equation-oriented (EO) mathematical model for the optimization of heat and power systems using a new state-of-the-art sequential quadratic programming (SQP) method called filterSQP has been reported in an earlier paper. The model has been extended to include combined cycle cogeneration plants (CCCPs), the economic optimization of which involves adding equipment investment, cost functions and operating cost models to the stream and unit operation models of the earlier paper. These systems are of substantial industrial interest and are substantially larger than those in Rodrı́guez-Toral et al., Computers and Chemical Engineering, August 2000. Their size and complexity required the use of a new flexible modelling system (FMS) recently created within our research group. FMS can be used to set up large systems of equations, create networks to be modelled and give starting guesses easily for problems of any size. Also, FMS is able to interact with solvers for EO simulation and optimization, which have been developed here and elsewhere. A number of EO simulation and optimization examples, from simple unit operations to a whole real cogeneration plant involving a commercial gas turbine with 1275 variables and equations, are used to demonstrate the applicability of the CCCP model and the modelling package.

A new harvest operation cost model to evaluate forest harvest layout alternatives

In this paper we develop a new model for harvest operation costs that can be used to evaluate stands for potential harvest. The model is based on felling, extraction, and access costs and is unique in its consideration of the interaction between harvest area shapes and access roads. We illustrate the model and evaluate the impact of stand size, volume, and road cost when determining harvest layouts. We also present a generalized case where multiple unit road costs are considered in the same stand.

99/01176 A new approach for IGCC process synthesis under uncertainty : Rubin, E. S. and Diwekar, U. M. EC(Am. Soc. Mechanical Eng.), 1997, 5, 1–7

99/01176 A new approach for IGCC process synthesis under uncertainty : Rubin, E. S. and Diwekar, U. M. EC(Am. Soc. Mechanical Eng.), 1997, 5, 1–7

Engineering application of the acid leaching kinetics of a manganese carbonate ore

Based on the test results of the acid leaching of a MnCO 3 ore and on the kinetic model obtained earlier, an engineering application has been approached from different ways: a summing method for the calculation of the total conversion of a multiparticulate system over a wide size range (in fact, an actual ore pulp); a set of computing procedures for the estimation of the leaching conversion in different operating systems (e.g., batch stirred tank, and a series of co-current or counter-current CSTR), and a minimum capital and operating cost model for the determination of the optimum conditions of the leaching process.