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1
McArdle, A. J., A. J. McDiarmid e T. E. Asbey. "PRODUCTION OPTIMISATION VIA MULTI-PHASE FLOW METERING". APPEA Journal 45, n. 1 (2005): 97. http://dx.doi.org/10.1071/aj04008.
Abstract (sommario):
Apache has developed a number of small oil fields using unmanned minimum facilities platforms close to Varanus Island, on the North West Shelf of Western Australia. Production from each platform is commingled into a single production trunkline. Wells producing at high watercut are artificially lifted using gaslift. Production monitoring and well allocation uses multi-phase flow meters situated on each platform. The use of these meters minimises total infrastructure cost, while still allowing the direct testing of each well. Test results are used for production optimisation of the individual wells, optimisation of the integrated production network, well and field production allocation and troubleshooting. Meter performance has been satisfactory, resulting in an additional unit being deployed on the Stag field where production is affected by high gas rates, slugging and sand production.
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Al-Chalabi, Hussan Saed, Jan Lundberg, Majid Al-Gburi, Alireza Ahmadi e Behzad Ghodrati. "Model for economic replacement time of mining production rigs including redundant rig costs". Journal of Quality in Maintenance Engineering 21, n. 2 (11 maggio 2015): 207–26. http://dx.doi.org/10.1108/jqme-07-2014-0041.
Abstract (sommario):
Purpose – The purpose of this paper is to present a practical model to determine the economic replacement time (ERT) of production machines. The objective is to minimise the total cost of capital equipment, where total cost includes acquisition, operating, maintenance costs and costs related to the machine’s downtime. The costs related to the machine’s downtime are represented by the costs of using a redundant machine. Design/methodology/approach – In total, four years of cost data are collected. Data are analysed, practical optimisation model is developed and regression analysis is done to estimate the drilling rigs ERT. The artificial neural network (ANN) technique is used to identify the effect of factors influencing the ERT of the drilling rigs. Findings – The results show that the redundant rig cost has the largest impact on ERT, followed by acquisition, maintenance and operating costs. The study also finds that increasing redundant costs per hour have a negative effect on ERT, while decreases in other costs have a positive effect. Regression analysis shows a linear relationship between the cost factors and ERT. Practical implications – The proposed approach can be used by the decision maker in determining the ERT of production machines which used in mining industry. Originality/value – The research proposed in this paper provides and develops an optimisation model for ERT of mining machines. This research also identifies and explains the factors that have the largest impact on the production machine’s ERT. This model for estimating the ERT has never been studied on mining drilling rigs.
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Andrawus, Jesse A., John Watson, Mohammed Kishk e Heather Gordon. "Optimisation of Wind Turbine Inspection Intervals". Wind Engineering 32, n. 5 (ottobre 2008): 477–90. http://dx.doi.org/10.1260/030952408786411921.
Abstract (sommario):
The choice of correct inspection intervals poses a serious challenge to industries that utilise physical assets. Too short an interval increases operational cost and waste production time while too long an interval increases the likelihood of unexpected asset failures. Failure Modes and Effect Criticality Analysis (FMECA) is a technique that permits qualitative evaluation of assets' functions to predict critical failure modes and the resultant consequences to determine appropriate maintenance tasks for the assets. The Delay-Time Maintenance Model (DTMM) is a quantitative maintenance optimisation technique that examines equipment failure patterns by taking into account failure consequences, inspection time and cost in order to determine optimum inspection interval. In this paper, a hybrid of FMECA and DTMM is used to assess the failure characteristics of a selected subsystems of a chosen wind turbine. Optimal inspection intervals for critical subsystems of the wind turbine are determined to minimise its total life-cycle cost.
4
Salmachi, Alireza, Mohammad Sayyafzadeh e Manouchehr Haghighi. "Optimisation and economical evaluation of infill drilling in CSG reservoirs using a multi-objective genetic algorithm". APPEA Journal 53, n. 1 (2013): 381. http://dx.doi.org/10.1071/aj12034.
Abstract (sommario):
Water production in the early life of Coal Seam Gas (CSG) recovery makes these reservoirs different from conventional gas reservoirs. Normally, a large amount of water is produced during the early production period, while the gas-rate is negligible. It is essential to drill infill wells in optimum locations to reduce the water production and increase the gas recovery. To optimise infill locations in a CSG reservoir, an integrated framework is developed to couple the reservoir flow simulator (ECLIPSE) and the genetic algorithm (GA) optimisation toolbox of (MATLAB). In this study, the desired objective function is the NPV of the infill drilling. To obtain the economics of the infill drilling project, the objective function is split into two objectives. The first objective is the gas income; the second objective is the cost associated with water production. The optimisation problem is then solved using the multi-objective solver. The economics of the infill drilling program is investigated for a case study constructed based on the available data from the Tiffany unit in San Juan basin when gas price and water treatment cost are variable. Best obtained optimal locations of 20 new wells in the reservoir are attained using this optimisation framework to maximise the profit of this project. The results indicate that when the gas price is less than $2/Mscf, the infill plan, regardless of the cost of water treatment, is not economical and drilling additional wells cannot be economically justified. When the cost of water treatment and disposal increases from $0.01/STB to $4/STB, the optimisation framework intelligently distributes the infill wells across the reservoir in a way that the total water production of infill wells is reduced by 26%. Simulation results also indicate that when water treatment is an expensive operation, lower water production is attained by placing the infill wells in depleted sections of the coal bed, close to the existing wells. When water treatment cost is low, however, infill wells are freely allocated in virgin sections of the coal bed, where both coal gas content and reservoir pressure are high.
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Purnomo, Muhammad Ridwan Andi. "Incorporating deep learning data analytics techniques in the optimisation of capacitated planned maintenance". Jurnal Sistem dan Manajemen Industri 6, n. 2 (30 dicembre 2022): 167–75. http://dx.doi.org/10.30656/jsmi.v6i2.5076.
Abstract (sommario):
Manufacturing systems must be supported by the availability of materials, a streamlined production process and a prepared production line to achieve the production target. In a mass customization manufacturing system, the number of machines required for customization is relatively small. Conse-quently, maintenance on critical machines will impact this manufacturing system the most. Two types of maintenance strategies are implemented: corrective and preventive maintenance. The corrective maintenance requires more resources since the time and cost to repair the breakdown machine will be higher due to fatal failure. For the management to consider preventive maintenance while the binding machines are still operational, it must be equipped with a deep analysis demonstrating that fewer resources will be required. This paper discusses two deep analyses: accurate prediction of the binding machines' breakdown based on Mean Time Between Failure (MTBF) data using a deep learning data analytics technique and optimizing the maintenance total cost in the available capacitated time. The findings and results of this paper show that the proposed deep learning data analytics technique can increase the MTBF prediction accuracy by up to 66.12% and reduce the total maintenance cost by up to 4% compared with the original model.
6
Banyai, Agota. "MATERIAL REQUIREMENT PLANNING FOR BUILD-TO-SEQUENCE SUPPLY: A MULTI-LEVEL OPTIMISATION APPROACH". Journal of Production Engineering 25, n. 1 (30 giugno 2022): 25–30. http://dx.doi.org/10.24867/jpe-2022-01-025.
Abstract (sommario):
Material requirement planning (MRP) plays an important role in the life of production companies, because it has a great impact on the efficiency of manufacturing operations and it influences the total cost. Just-in-time and just-in-sequence supply offer new solutions to improve the cost-efficiency from inventory holding point of view. Within the frame of this article the author focuses on the build-to-sequence strategy of just-in-sequence supply and demonstrate an integrated approach of material requirement planning. The suggested methodology includes the determination of build-to-sequence orders, the optimisation of material requirement from lead time and cost point of view and determine the optimal sequence of operations to fulfil build-to-sequence demands. The computational results show, that the integrated optimisation leads to an increased cost efficiency, while the required manufacturing operations are performed with a decreased lead time.
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Fu, Peng, Danny Pudjianto, Xi Zhang e Goran Strbac. "Integration of Hydrogen into Multi-Energy Systems Optimisation". Energies 13, n. 7 (1 aprile 2020): 1606. http://dx.doi.org/10.3390/en13071606.
Abstract (sommario):
Hydrogen presents an attractive option to decarbonise the present energy system. Hydrogen can extend the usage of the existing gas infrastructure with low-cost energy storability and flexibility. Excess electricity generated by renewables can be converted into hydrogen. In this paper, a novel multi-energy systems optimisation model was proposed to maximise investment and operating synergy in the electricity, heating, and transport sectors, considering the integration of a hydrogen system to minimise the overall costs. The model considers two hydrogen production processes: (i) gas-to-gas (G2G) with carbon capture and storage (CCS), and (ii) power-to-gas (P2G). The proposed model was applied in a future Great Britain (GB) system. Through a comparison with the system without hydrogen, the results showed that the G2G process could reduce £3.9 bn/year, and that the P2G process could bring £2.1 bn/year in cost-savings under a 30 Mt carbon target. The results also demonstrate the system implications of the two hydrogen production processes on the investment and operation of other energy sectors. The G2G process can reduce the total power generation capacity from 71 GW to 53 GW, and the P2G process can promote the integration of wind power from 83 GW to 130 GW under a 30 Mt carbon target. The results also demonstrate the changes in the heating strategies driven by the different hydrogen production processes.
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Korkulu, Sezen, e Krisztián Bóna. "Development of a Lot-Sizing Model to Prevent Heat Stress and Work-Related Musculoskeletal Disorders". Promet - Traffic&Transportation 33, n. 6 (13 dicembre 2021): 871–82. http://dx.doi.org/10.7307/ptt.v33i6.3837.
Abstract (sommario):
Management of heat stress and metabolic cost is vital for preventing any work-related disorders. In this paper, we integrated rest time formulations for heat strain and metabolic cost to develop a new lot sizing model for preventing heat exposure and work-related musculoskeletal disorders. The effects of heat strain and rest allowance on the total cost of the production supply process were investigated. The problem studied in this paper was the handling of the raw materials placed in boxes by manual material handling in order to supply the material requirement of a production line placed in a production area. For the realisation of the material handling transactions between the raw material warehouse and the production line, Electric Pallet Jack (EPJ) was used. The study covers the investigation of picking, storing, and carrying motions for the manual handling of these materials. The result of the analysis has shown that 8.5% savings were achieved by using the heat strain and rest time in comparison to the total cost of this part of the production line supply process with the ISO 7243 maximum metabolic work limit. Consequentially, the analysis results showed that the developed method demonstrated the viability of lot sizing model optimisation with multiple objectives and complex constraints with regards to the metabolic cost and heat strain.
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Zhao, Gang. "Design and optimisation of advanced bearing system for ultra-precision plastic electronics production systems". Industrial Lubrication and Tribology 71, n. 2 (11 marzo 2019): 253–57. http://dx.doi.org/10.1108/ilt-12-2017-0370.
Abstract (sommario):
Purpose The paper aims to use aluminium alloy to substitute steel as the main material of ultra-precision hydro-static bearing system for an ultra-precision plastic electronics production system to lower the manufacturing cost. The total cost of diamond turning and nickel-based electroless coating of an aluminium alloy bearing is expected to be less than the cost of manufacturing a stainless steel bearing. Design/methodology/approach The paper used a large amount of theoretical calculation to obtain optimal specifications of the bearing system. ANSYS modelling was selected to simulate the deflection of the bearing shaft under high oil pressure. Hundreds of measurements were conducted after the bearing had been manufactured. Findings The paper provides industrial application insights on using aluminium alloy with a high-quality nickle-based electroless coating as a successful substitution of stainless steel. This created a more economic hydro-static bearing system. Research limitations/implications Because of the time limit, different rotational speed tests shall be conducted in the future. Practical implications The paper provides implications for the application of nickel-based electroless coating to improve the surface property and bending strength of aluminium alloy, as well as classifying ultra-precision diamond turning as an economic finishing process. Originality/value This paper has identified the importance of aluminium alloy with a nickel-based electroless coating as the substitution of stainless steel in a precision hydro-static bearing system.
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Mohammed, Nuhu, Ademola Bello Adisa, Mohammed Ahmed Bawa e Habou Dandakuta. "Design of Wind/Diesel Generator Micro-Grid Power System in Kano, Nigeria, Using Homer". International Journal of Engineering & Technology 7, n. 3.36 (6 maggio 2018): 16. http://dx.doi.org/10.14419/ijet.v7i3.36.29072.
Abstract (sommario):
A micro-grid system has been designed using wind/diesel generators power sources. The system is aimed to cater for the electricity demand of Kwankwasiyya city Kano, Nigeria. The city has about 400 housing units with average daily electricity demand of 10000 kWhr. The project employed the use of homer, a software that performs Hybrid Optimization Model for Electric Renewables. The most appropriate system architecture was chosen from the optimisation result based on the selection factors set (initial investment cost, total electrical production to site primary demand ratio and so on). A system comprising single wind turbine (800 kW), and two generators of 400 kW and 300kW has been selected based on the selection criteria. The electrical output shows that 82% of the total production will be consumed onsite with the remaining would be sold to the grid. The system has a cost of energy value of 0.279 kWh with net present cost of about $11,000,000. The system is economically viable considering the need of reliable power in the region even though, the price of the electricity is higher than what is obtainable from the grid.
11
Zhang, Yusheng, e Adrian L. Collins. "Optimisation of Cereal Farm Strategies for Mitigating Externalities Associated with Intensive Production". Water 15, n. 1 (31 dicembre 2022): 169. http://dx.doi.org/10.3390/w15010169.
Abstract (sommario):
Intensive cereal farming results in various unintended consequences for the environment including water pollution. Current uptake of on-farm best management measures in the UK is delivering limited benefits and alternative management futures need to be modelled to make informed decisions. The Farmscoper (FARMSCale Optimization of Pollutant Emission Reductions) tool was used to examine two management scenarios for intensive cereal farms in eastern England. The first was based on increased uptake of those measures currently recommended by advisory visits and following walkover surveys. The second was founded on mechanistic understanding of on-farm pollutant sources embedded in the Farmscoper tool. Optimization of measure selection used a multi-objective genetic algorithm. The technically possible reductions (e.g., 10 to 21% for sediment and 12 to 18% for total phosphorus) of current pollutant emissions to water due to uptake of the mechanistic scenario exceeded those resulting from the current advice scenario (≤5%), but with mixed impacts on costs ranging from a saving of £34.8/ha/yr to an increase of £19.0/ha/yr, relative to current best management costs. The current advice scenario generated corresponding cost savings of between £30.4/ha/yr and £73.40/ha/yr. Neither scenario is sufficiently impactful on unintended consequences, pointing to the need for structural change in land cover.
12
Dabee, Faraj El, Romeo Marian e Yousef Amer. "A Robust Optimisation Approach of a Simultaneous Cost-Risk Reduction under a Just-in-Time Environment Using a Genetic Algorithm". Applied Mechanics and Materials 743 (marzo 2015): 307–16. http://dx.doi.org/10.4028/www.scientific.net/amm.743.307.
Abstract (sommario):
This paper addresses the problem of simultaneously minimising the total costs of the final product produced by systems adopting a JIT approach. A cost which incorporates both the cost of production processes and the cost arising from the many potential risks associated with any reduction. A robust genetic approach is proposed in order to optimise the novel mathematical model published in [1]. Genetic operators adopted to improve the genetic search algorithm are introduced and discussed. Experiments are conducted to evaluate the performance of the proposed algorithm and an illustrative example is given. A comparison of the genetic operators used is made by means of evaluating different rates, to define the most suitable rate of crossover and mutation. The findings illustrate the effectiveness of the proposed approach in the JIT system with focus on simultaneous cost-risk reduction.
13
Bochniak, Andrzej, e Monika Stoma. "Estimating the Optimal Location for the Storage of Pellet Surplus". Energies 14, n. 20 (14 ottobre 2021): 6657. http://dx.doi.org/10.3390/en14206657.
Abstract (sommario):
This paper deals with the problem of managing the surplus that arises during the seasonal production of pellets, which will be sold in the period of increased demand. Dijkstra’s algorithm is used in issues connected with finding a new storage place with a view of the optimisation of the transport costs of pellets produced by a company in 18 different towns in the Lubelskie Voivodeship in Poland. The most optimal location for the new pellet storage site has been determined, for which the total length of the traveled routes is the shortest, taking into account the actual shares of individual plants in the total production. The construction of the graph with the shortest paths was made on the basis of the existing network of available transport roads, and the nodes of the graph were their intersections. The most advantageous storage location of pellets was identified by the calculation the total transport cost using a minimum-cost tree of shortest paths. Based on the estimated transport assumptions, the lowest total cost of transport from all 18 plants was 3092.0 (km), which corresponds to an average distance to production plants of 89.7 km and 61.7 km to estimated selling distribution. The new storage point is suggested near the town of Piaski. Average cost of travel for all trees obtained for existing plant locations and subsequent distribution to points of sale was 4113.7 (km), while standard deviation 735.2 (km). Additionally, a relative increase in costs was estimated in the case of selecting other locations. Using spatial interpolation and geoprocessing tools, a map—showing the increase in pellet transport costs in relation to the most optimal solution—was developed. The constructed map allows for a better analysis of cost increases than a single point. It was stated that the increase in transport costs does not exceed 10% of lowest cost for 17.6% area of studied area. It was found that the most convenient area is shifted to the south of the voivodship and improperly adopted storage location can increase transport costs by up to 75%.
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Bochniak, Andrzej, e Monika Stoma. "Estimating the Optimal Location for the Storage of Pellet Surplus". Energies 14, n. 20 (14 ottobre 2021): 6657. http://dx.doi.org/10.3390/en14206657.
Abstract (sommario):
This paper deals with the problem of managing the surplus that arises during the seasonal production of pellets, which will be sold in the period of increased demand. Dijkstra’s algorithm is used in issues connected with finding a new storage place with a view of the optimisation of the transport costs of pellets produced by a company in 18 different towns in the Lubelskie Voivodeship in Poland. The most optimal location for the new pellet storage site has been determined, for which the total length of the traveled routes is the shortest, taking into account the actual shares of individual plants in the total production. The construction of the graph with the shortest paths was made on the basis of the existing network of available transport roads, and the nodes of the graph were their intersections. The most advantageous storage location of pellets was identified by the calculation the total transport cost using a minimum-cost tree of shortest paths. Based on the estimated transport assumptions, the lowest total cost of transport from all 18 plants was 3092.0 (km), which corresponds to an average distance to production plants of 89.7 km and 61.7 km to estimated selling distribution. The new storage point is suggested near the town of Piaski. Average cost of travel for all trees obtained for existing plant locations and subsequent distribution to points of sale was 4113.7 (km), while standard deviation 735.2 (km). Additionally, a relative increase in costs was estimated in the case of selecting other locations. Using spatial interpolation and geoprocessing tools, a map—showing the increase in pellet transport costs in relation to the most optimal solution—was developed. The constructed map allows for a better analysis of cost increases than a single point. It was stated that the increase in transport costs does not exceed 10% of lowest cost for 17.6% area of studied area. It was found that the most convenient area is shifted to the south of the voivodship and improperly adopted storage location can increase transport costs by up to 75%.
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Allison, Nick. "More bang for your buck: optimising CSG extraction to achieve increased project value". APPEA Journal 56, n. 1 (2016): 75. http://dx.doi.org/10.1071/aj15007.
Abstract (sommario):
Recent challenges within Australia’s oil and gas market have placed increased pressure on Australia’s CSG industry to reel-in burgeoning project costs. In a tight commodity price environment, developments need to extract greater value from projects. This paper outlines an innovative approach to CSG gathering system design by leveraging the digital oil field approach, utilising technology to rapidly optimise design, reduce design costs and optimise the development processes behind economic resource extraction aimed at ultimately delivering increased project value. In the past few years a step-change has been made in the optimisation of the engineering design model, with expanded concept level design, FEED-less design, and partially automated detailed design being executed on gathering system projects now being adopted. This was a step towards a fully integrated approach of the digital oil field. Through this process, it has become apparent that this methodology can be extended further through the targeted optimisation of the production model used in the establishment of CSG projects. This will enable increased revenue for a project. Field production profiles for both gas and water can be developed from preliminary reservoir assessment data. Using cost data for materials and installation, various scenarios can be assessed to optimise production volumes, surface infrastructure configuration, and total volume extracted on a dollar margin per unit energy basis. The optimisation measures explored in this paper are most critical to reservoir locations with a low drainage area per well, where reservoir drainage is maximised by refinement of the configuration of above-ground infrastructure. This has the potential to translate to a more optimised network, and greater profitability in the development of large-scale CSG fields.
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Johnson, R. L., Jr, C. W. Hopkins e M. D. Zuber. "TECHNICAL CHALLENGES IN THE DEVELOPMENT OF UNCONVENTIONAL GAS RESOURCES IN AUSTRALIA". APPEA Journal 40, n. 1 (2000): 450. http://dx.doi.org/10.1071/aj99026.
Abstract (sommario):
Unconventional gas resources, defined as low- permeability sandstone, coal seam and naturally- fractured shale gas reservoirs, represent a huge potential resource for future natural gas supply in Australia and around the world. Because low individual well-production rates are often the norm, unconventional reservoir development may involve the drilling of hundreds of wells to make the economics attractive. Thus, careful planning, sound development strategies and cost control are critical for project success.Virtually all unconventional gas resources must be stimulated to be economic; stimulation costs are often the most significant amount of the total well expenditure. Thus, a cost-effective method for reservoir characterisation and fracture treatment optimisation is required. Because of marginal economics, techniques used to analyse the process and results are often oversimplified; this can lead to confusing or inadequate descriptions of the complex behavior of a hydraulically-fractured, low- permeability reservoir and in some cases bad development decisions. Detailed data collection programs and fracture treatment optimisation strategies are essential to adequately address the technical issues involved in unconventional reservoir development.Besides the technical challenges associated with unconventional gas development, good forethought is necessary as to the planning and execution of the overall project. The development scenarios for coal seam and low-permeability sandstone gas resources are highly statistical and succeed or fail based on the average performance of the group of wells within the project. Following proven guidelines and methods during development while integrating key technologies into the planning and optimisation process are essential for success in unconventional reservoir development.
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Edun, Bose Mosunmola, Oluseyi O. Ajayi e Philip Olufemi Babalola. "Failure Mode and Cost Effect Analysis of a Model Bone Crushing Hammer". Key Engineering Materials 917 (13 aprile 2022): 63–69. http://dx.doi.org/10.4028/p-z01ver.
Abstract (sommario):
Critical investigation of strength properties of materials is required in Engineering practice to ensure an enhanced service life. Globally, industrialists are struggling to increase cost savings from lost production due to the failure of machine, while customers are concerned about the safety and reliability of the products. Hammer mills are prone to various modes of failure like chemical failure, erosive failure, abrasive failure and fatigue failure. The effect of these failure modes is always detrimental to the operation of the machine and its efficiency. Hence, forensic investigation is essential to determine the failure modes and their effects on hammer mills for bone crushing. Field investigation was carried out to monitor the hammer mill in operation for 12 months with a production of 20 bags per hour. The total production per day for 8 hours is expected to be 160 bags at a given speed. Thus, the cost of machine downtime on production is huge. The Pareto method was used to determine the effect of downtime on revenue and production for a period of one year. The hours of failure were between 1 to 2 hours per day. The loss in revenue was calculated using the variation of number of failure with time, as obtained from hammer mill. The outcome showed that hammers investigated failed as a result of abrasive wear, fatigue, impact, and chemical wear, respectively. The cost of downtime was found to be $ 37,745,809,920.00 CAD for the period of study. Based on findings, wide ranging factors are required to evaluate the performance of the hammer mill for improved productivity and efficiency. These are proper material selection, design and appropriate operational parameters. However, there is need for optimisation of the hammer material via heat treatment methods as this will reduce the yearly cost of production, downtime of the milling machine for bone crushing as well as improvement in productivity.
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Susilaningsih, Dwi, Tami Astie Uhtiza e Khairul Anam. "SUBSTITUTION COMPONENT CULTIVATION MEDIA OF PHOTO-FERMENTATION PROCESS FOR LOW COST HYDROGEN GAS BIOPRODUCTION". Teknologi Indonesia 40, n. 2 (10 aprile 2018): 108. http://dx.doi.org/10.14203/jti.v40i2.378.
Abstract (sommario):
Employing the Rhodobium marinum bacteria as an agent of hydrogen bioproduction with facultative fermentation condition needs two steps of cultivations, i.e., pre-culture and hydrogen production periods with different media. The two steps cultivation is important state for hydrogen gas production rate. ASY (Ammonium, Succinate, and Yeast extract) is usually used as standard medium in biohydrogen production and mostly the component is analytical grade of chemicals. Series of cultivation media substitution by combining ASY with other cost-effective chemicals were investigated. The total of sixteen combinations of media were observed (P0-P15). Cultivation condition of R. marinum was set in an illuminated light of 31.17 µmol s-1m-2photon and agitated in shaker of 120 rpm for nine days. The experiment was designed as random selection with anova analyses. The results exhibited that P7 medium combination released the highest hydrogen gas of 61.29±0.52 ml/80 ml media among the others combination media. Using one-way ANOVA, there was a statistically significant difference between the mean number and condition and it was found P7 was significantly different with the others combination media, except P7 was insignificantly different with P3 only. Overall, the combination media is cheaper than the ASY medium. The ASY medium price is about USD 677, and the substitution media prices were ranging from USD 4.24 to USD 613.47. However, the further research on optimisation cultivation condition is needed.
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Rajendran, Venkatesh, S. R. Devadasan e S. Kannan. "Design of a Logistics Network in an Organisation for Optimising Logistics Cost and Inventory Using RSM and Genetic Algorithm". Applied Mechanics and Materials 592-594 (luglio 2014): 2601–7. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.2601.
Abstract (sommario):
The competitive environment of global markets has forced many manufacturers to select the most appropriate logistics for the optimisation of total logistics costs, time and inventory. Cost and time are the two important factors in the competitive market that are often not addressed comprehensively by the researchers. In this study, the genetic algorithms (GAs) and the fuzzy logic techniques are used for optimising a novel mathematical model of the logistics network. The objective of the proposed model is to minimise the costs of production, distribution, holding and backorder. In addition to the optimization of logistics costs, the model can also determine the economic production quantity (EPQ), and with help of the GAs and the Fuzzy logic solver with probability parameters and various dimensions for validation of the studied model in real-life situations, and we compared the outputs to demonstrate the performance of the two optimization techniques . Using Genetic Algorithm and fuzzy logic, the optimized value of the logistics cost, and volume of the logistics network were obtained.
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Karbassi Yazdi, Amir, Mohamad Amin Kaviani, Amir Homayoun Sarfaraz, Leopoldo Eduardo Cárdenas-Barrón, Hui-Ming Wee e Sunil Tiwari. "A comparative study on economic production quantity (EPQ) model under space constraint with different kinds of data". Grey Systems: Theory and Application 9, n. 1 (4 febbraio 2019): 86–100. http://dx.doi.org/10.1108/gs-08-2018-0035.
Abstract (sommario):
PurposeThe purpose of this paper is to develop a multi-item economic production quantity (EPQ) strategy under grey environment and space constraint. Since the “demand” cannot be predicted with certainty, it is assumed that data behave under grey environment and compare the proposed inventory model with other studies using crisp or fuzzy environments.Design/methodology/approachThis paper is to optimise the cycle time and total cost of the multi-item EPQ inventory model. For this purpose, the Lagrangian coefficient is used to solve the constrained optimisation problem. The grey relational analysis approach and grey data are applied in developing the EPQ inventory model.FindingsThe results are compared with the analysis using crisp and fuzzy data. Sensitivity analysis is done to illustrate the effect of parameter variations on the optimal solution. The results of the study demonstrate that crisp data outperform the other two data in all scales problems in terms of cycle time and cost; grey data perform better in all scales problems than fuzzy data.Originality/valueThe contribution of this research is the use of grey data in developing the EPQ inventory model with space constraint.
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Mojisola A., *Bolarinwa,, e Fajebe, Fisayo E. "Multi-Criteria Inventory Optimisation of University of Ibadan, Ibadan, Nigeria’s Bakery Using Goal Programming Approach and Flour as the Major Raw-Material". International Journal of Scientific Research and Management 9, n. 12 (17 dicembre 2021): 650–60. http://dx.doi.org/10.18535/ijsrm/v9i12.ec02.
Abstract (sommario):
Asides inventory cost, which is being used as the only inventory performance measure at the University of Ibadan bakery, a number of other criteria, such as inventory cost, service level, inventory turnover and delivery lead time which influence the performance of an inventory system have surfaced over the years. Hence, there is the need to examine all these criteria-objectives altogether. Therefore, this research was centred towards optimising the inventory system of University of Ibadan bakery, putting multiple criteria into consideration.
Data on 17 raw materials: their costs, suppliers, usage rate, lead time, storage space and available capital were collected by means of interviews, past records and observations. The weighted goal program algorithm was adopted to find the best compromise between fulfilling the four objectives by minimising the sum of the deviation from the target values of the goals. Subsequently, Lingo 17.0 and Tora 1.0 optimisation software packages were used to solve and compare the model generated, while putting into consideration storage space constraint and budgeted capital.
The developed model from the goal programming algorithm exhibited four goals (combined into one objective function). Same solutions were obtained from Lingo 17.0 and Tora 1.0. While Lingo 17.0 gave a uniform service level of 100% , a turnover ratio greater than 1(>1) for all the materials at a negligible increase (of < 0.0001%) in total inventory cost of the raw materials and available lead time duration of zero days (< 24 hours) for each material, Tora 1.0 gave a uniform service level of 100% , a turnover ratio greater than 1 (> 1) for all the materials at a negligible increase (of < 0.0001%) in total inventory cost of the raw materials and available lead time duration of zero days (< 24 hours) for each material.
Implementation of the developed model will eliminate unnecessary waiting time between production, thereby ensuring effective and efficient utilisation of raw materials in production which will lead to reduced cost of holding inventory, elimination of unnecessary overall cost and wastages, and also improvement of the productivity and profit on the long run.
22
Skoglund, Ida E. U., Mette Rostad e Kasper E. Thorvaldsen. "Impact of shared battery energy storage system on total system costs and power peak reduction in commercial buildings". Journal of Physics: Conference Series 2042, n. 1 (1 novembre 2021): 012108. http://dx.doi.org/10.1088/1742-6596/2042/1/012108.
Abstract (sommario):
Abstract The power system is experiencing an increasing share of renewable and intermittent energy production and increasing electrification. However, these changes are creating high power peaks, are straining the grid and call for expensive investments in expansions and improvements. This paper examines how the operational strategy of shared battery energy storage systems (s-BESS) can address these issues for commercial buildings with relatively high power peaks. Due to the uncertainty in long-term costs when subject to a measured peak (MP) grid tariff, the scheduling of the battery is optimised with a receding horizon control algorithm. The optimisation model is used on a Norwegian real-life case study to find the best possible configuration with an already existing battery. Although current Norwegian regulations challenge the possibility for shared metering and billing for a s-BESS configuration, the results show that the total system cost was reduced by 19.2% compared to no battery. The community peak was reduced by 17.8% compared to no battery and 6.22-17.5% compared to individual storage, which indicates that s-BESS is of value for the DSO as well.
23
Kowalewski, Mirosław, e Małgorzata Murawska. "Compliance and Non-Compliance Costs in Selected Manufacturing Enterprises". Olsztyn Economic Journal 7, n. 1 (30 giugno 2012): 121–32. http://dx.doi.org/10.31648/oej.3411.
Abstract (sommario):
Quality cost analysis is considered a very important instrument used in quality economics. Interpretation of changes in the quality cost level, cost optimisation effectiveness and indicating the directions for quality improvement plan verification represent the subject of this analysis. Evaluation of the compliance and non-compliance costs in the development of quality costs in a selected enterprise during the years 2004-2009 was the main goal of this study. A limited liability company conducting manufacturing activity in the province of Warmia and Mazury was selected which mainly produces accessories to automotive vehicles and machines. As the result of the conducted studies, the following ultimate conclusions were formulated: - quality costs in the enterprise surveyed showed an increasing trend during the years 2004-2007 and as of 2008 a decreasing trend was observed (in 2009 they decreased by 17% as compared to 2008), - the ratio of losses from the total defective production during the years 2004-2006 showed a decreasing trend; the significant change in the value of defective products manufactured proves the efficiency of the quality management system applied in the company, - with the increase in the costs of activities related to preventing poor quality, the costs of defective products and the total quality costs decrease.
24
Andreou, Eleni, e Sudipta Roy. "Electroforming 4.0 – Significance, Challenges & Optimisation". ECS Meeting Abstracts MA2022-02, n. 23 (9 ottobre 2022): 982. http://dx.doi.org/10.1149/ma2022-0223982mtgabs.
Abstract (sommario):
Since the concept of “Industry 4.0” was introduced the most competitive industrial manufacturers around the world have been trying to secure sustainable, high quality, low-cost technological developments. Alongside the total computerisation of manufacturing and fabrication, new manufacturing technologies will need to arise to replace traditional production lines with more flexible ones able to support the evolved industrial needs of the next transition. Among these technologies, additive manufacturing processes have significantly contributed to the rapid transformation of the industrial landscape during the last decade. In particular, “low-volume/high-value" industrial sectors, such as the aerospace, marine and energy industries, are expected to benefit from this kind of approaches. This is mainly because manufacturing of larger volumes of customised products could be achieved in that manner, followed by a reduction of industrial and economic waste, decrease in the cost of operation and reduction of environmental impact. Electroforming is increasingly gaining recognition as a promising and sustainable additive manufacturing process of the “Industry 4.0” era. Numerous important laboratory-scale studies try to shed light onto the pressing question as to which are the best industry approaches to be followed towards the process’s optimisation. However, for electroforming to be successfully optimised and efficiently applied in industry, systematic scale up studies need to be conducted. Well-informed simulations can provide a much-desired insight into the novelties and limits of the process, and therefore, scaling up modelling studies are of essence. Additive-free nickel electroforming, in particular, could also play an important role in the much-desired “green” transition of lightweight manufacturing. Even within the currently available infrastructure, the same electroforming reactors can remain in use for years if properly maintained, the stainless-steel cathodes (mandrels) and titanium anode baskets are re-usable and recyclable, while process efficiency (especially for sulphamate baths) is usually close to 100%. Hazards arising from the use of nickel can easily be mitigated, while developments on nickel recovery and recycling are increasingly promising. Modelling studies can help further, towards process optimisation at all three (system, process and product) sustainability levels. Since electroforming’s final products can be of various scales and requirements, well-informed modelling studies could assist with efficient tooling and process design for different cases. That way, key process parameters, such as the deposition duration, applied currents, heating and agitation requirements, or even quantitative material requirements, could be fine-tuned on a case-by-case basis. Therefore, to better understand the process and its potential, a systematic nickel electroforming modelling approach was followed; starting from primary current distribution (PCD) simulations which depend solely on the system’s geometry, moving forward to introducing kinetic contributions through secondary current distribution (SCD) studies and, finally, developing tertiary current distribution (TCD) models completed by the introduction of mass transfer effects. In practice, time-dependent nickel electroforming models of different scales were developed and studied using COMSOL Multiphysics®, a finite element method commercial software. The models were experimentally validated. Electrochemical experimental data, collected via polarisation studies, were used as input for the models. The boundary conditions at the cathode and anode were based on the overall nickel reduction and dissolution reactions, respectively. Current-potential data was used to fit the exchange current density, equilibrium potential, limiting current, as well as anodic and cathodic charge transfer coefficients. Modelling and experimental results were interpreted in terms of the deposit thickness distribution and uniformity. PCD modelling offered a preliminary insight into the system’s electrochemical behaviour, confirmed the direct relation between current and thickness distribution, and highlighted the dependence of the simulated results on the setup’s geometrical configuration. SCD simulations were subsequently used for mesh, geometry, and kinetic sensitivity studies, to be followed by TCD simulations involving multiple species and reactions. These studies confirmed that commercial simulation software can reliably model precision electrodeposition processes, such as electroforming. At the same time, the models’ credibility is dependent on good quality input parameters, derived through practical experiments. Among other observations, simplified SCD models were proven to be efficient in modelling processes not affected by tertiary phenomena. Targeted investigations on how the size, geometry and configuration of an electroforming reactor can affect the final product suggested time- and cost-effective modifications of the setup itself which can lead to process optimisation. Overall, computational studies allowed for the development of a study approach aiming to optimise both electroforming simulations and application in production lines. Figure 1
25
Cheng Seong, Khor. "A Model-Based Optimisation Approach for Process Synthesis of Olefins from Petroleum with Application to the Malaysian Petrochemical Industry". ASM Science Journal 12 (30 dicembre 2019): 1–15. http://dx.doi.org/10.32802/asmscj.2019.393.
Abstract (sommario):
The shale gas revolution has rekindled interest in olefins production due to the abundance of ethane as a raw material resource. However, the main technology still revolves around the cost-intensive distillation operation. Hence this work aims to investigate the economic optimisation of olefins synthesis from petroleum in the light of recent developments. A model-based approach is applied to determine the optimal sequencing of separation and reaction processes for a multi-component hydrocarbon mixture feed to produce mainly ethylene and propylene. a mixed-integer linear program (MILP) is formulated based on a superstructure that captures numerous plausible synthesis alternatives. The model comprises linear mass balance reactor representation and simple sharp distillation based on split fractions for product recovery. Integer binary variablesis used for selecting the task for equipment and continuous variables for representing the flowrate of each task. To expedite converging to an optimal solution of a least total annualised cost configuration, the formulation is appended with logical constraints on the design and structural specifications derived from heuristics based on practical knowledge and experience. The modelling approach on actual case studies based on two such petrochemical facilities operating in Malaysia is implemented. Additionally, the solution analysis is enriched with the investigation on a second- and third-best (suboptimal) configurations obtained through appropriate integer cuts as constraints to the model. The results show good agreement with existing plant configurations, thus substantiating the value and verification of the proposed model-based optimisation approach.
26
Niccolai, Alessandro, Gaia Gianna Taje, Davide Mosca, Fabrizio Trombello e Emanuele Ogliari. "Industrial Demand-Side Management by Means of Differential Evolution Considering Energy Price and Labour Cost". Mathematics 10, n. 19 (2 ottobre 2022): 3605. http://dx.doi.org/10.3390/math10193605.
Abstract (sommario):
In the context of the high dependency on fossil fuels, the strong efforts aiming to shift towards a more sustainable world are having significant economic and political impacts. The electricity market is now encouraging prosumers to consume their own production, and thus reduce grid exchanges. Self-consumption can be increased using storage systems or rescheduling the loads. This effort involves not only residential prosumers but also industrial ones. The rescheduling process is an optimisation problem that can be effectively solved with evolutionary algorithms (EAs). In this paper, a specific procedure for bridging demand-side management from the theoretical application to a practical industrial scenario was introduced. In particular, the toroidal correction was used in the differential evolution with the aim of preventing the local minima worsening the effectiveness of the proposed method. Moreover, to achieve reasonable solutions, two different cost contributions have been considered: the energy cost and the labour cost. The method was tested on real data from a historical textile factory, Ratti S.p.A. Due to the nature of the loads, the design variables were the starting time of the 30 shiftable loads. The application of this procedure achieves a reduction in the total cost of approximately 99,500 EUR/year.
27
Szymszal, J., M. Kuczyńska-Chałada e J. Król. "Management of Assortment Inventory Groups in Selected Foundry". Archives of Foundry Engineering 15, n. 3 (1 settembre 2015): 67–70. http://dx.doi.org/10.1515/afe-2015-0062.
Abstract (sommario):
Abstract As experience shows the practical, reliable assessment and optimisation of total costs of logistical processes implemented in supply chains of foundry plants is a quite complex and complicated process, because it requires to enclose all, without exception, performed actions, including them in various reference cross-sections, systematic activities and finally transforming them in a totally homogenous collection. Only solid analysis and assessment of assortment management in logistical supply systems in foundry plants of particular assortment groups allows to lower the supply costs significantly. In the article the analysis and assessment of the newest implemented optimising algorithms are presented in the process stock management of selected material groups used in a production process of a chosen foundry plant. A practical solution to solve a problem of rotary stock cost minimisation is given as well as of costs while creating a stock with the usage of economical volume and value of order.
28
Ulewicz, Robert, Karolina Czerwińska e Andrzej Pacana. "A Rank Model of Casting Non-Conformity Detection Methods in the Context of Industry 4.0". Materials 16, n. 2 (11 gennaio 2023): 723. http://dx.doi.org/10.3390/ma16020723.
Abstract (sommario):
In the face of ongoing market changes, multifaceted quality analyses contribute to ensuring production continuity, increasing the quality of the products offered and maintaining a stable market position. The aim of the research was to create a unified rank model for detection methods in the identification of aluminium casting non-conformities, in line with the paradigms of the fourth industrial revolution. The originality of the model enables the creation of a rank for the effectiveness of total inspection points allowing for the optimisation of detection methods. Verification of the model was carried out against the production process of aluminium casting. The model included the integration of non-destructive testing (NDT) methods and the analysis of critical product non-conformities, along with the determination of the level of effectiveness and efficiency of inspection points. The resulting ranking of detection methods indicated the NDT method as the most effective, which was influenced by the significant detection of critical non-conformities and the automation of the process. The study observed little difference in the visual inspection and measurement efficiency parameters, which was due to the identifiability of non-conformities with a lower degree of significance and the low level of inspection cost. Further research will look at the implications of the model in other production processes.
29
Heinschink, K., L. Shalloo e M. Wallace. "The costs of seasonality and expansion in Ireland’s milk production and processing". Irish Journal of Agricultural and Food Research 55, n. 2 (1 dicembre 2016): 100–111. http://dx.doi.org/10.1515/ijafr-2016-0010.
Abstract (sommario):
Abstract Ireland’s milk production sector relies on grass-based spring-calving systems, which facilitates cost advantages in milk production but entails a high degree of supply seasonality. Among other implications, this supply seasonality involves extra costs in the processing sector including elevated plant capacities and varying levels of resource utilisation throughout the year. If both the national raw milk production increased substantially (e.g. post-milk quota) and a high degree of seasonality persisted, extra processing capacities would be required to cope with peak supplies. Alternatively, existing capacities could be used more efficiently by distributing the milk volume more evenly during the year. In this analysis, an optimisation model was applied to analyse the costs and economies arising to an average Irish milk-processing business due to changes to the monthly distribution of milk deliveries and/or the total annual milk pool. Of the situations examined, changing from a seasonal supply prior to expansion to a smoother pattern combined with an increased milk pool emerged as the most beneficial option to the processor because both the processor’s gross surplus and the marginal producer milk price increased. In practice, it may however be the case that the extra costs arising to the producer from smoothing the milk intake distribution exceed the processor’s benefit. The interlinkages between the stages of the dairy supply chain mean that nationally, the seasonality trade-offs are complex and equivocal. Moreover, the prospective financial implications of such strategies will be dependent on the evolving and uncertain nature of international dairy markets in the post-quota environment.
30
Kabir, Imrana I., Juan Carlos Baena, Wei Wang, Cheng Wang, Susan Oliver, Muhammad Tariq Nazir, Arslan Khalid, Yifeng Fu, Anthony Chun Yin Yuen e Guan Heng Yeoh. "Optimisation of Additives to Maximise Performance of Expandable Graphite-Based Intumescent-Flame-Retardant Polyurethane Composites". Molecules 28, n. 13 (29 giugno 2023): 5100. http://dx.doi.org/10.3390/molecules28135100.
Abstract (sommario):
The effect of varying the weight percentage composition (wt.%) of low-cost expandable graphite (EG), ammonium polyphosphate (APP), fibreglass (FG), and vermiculite (VMT) in polyurethane (PU) polymer was studied using a traditional intumescent flame retardant (IFR) system. The synergistic effect between EG, APP, FG, and VMT on the flame retardant properties of the PU composites was investigated using SEM, TGA, tensile strength tests, and cone calorimetry. The IFR that contained PU composites with 40 wt.% EG displayed superior flame retardant performance compared with the composites containing only 20 w.t.% or 10 w.t.% EG. The peak heat release rate, total smoke release, and carbon dioxide production from the 40 wt.% EG sample along with APP, FG, and VMT in the PU composite were 88%, 93%, and 92% less than the PU control sample, respectively. As a result, the synergistic effect was greatly influenced by the compactness of the united protective layer. The PU composite suppressed smoke emission and inhibited air penetrating the composite, thus reducing reactions with the gas volatiles of the material. SEM images and TGA results provided positive evidence for the combustion tests. Further, the mechanical properties of PU composites were also investigated. As expected, compared with control PU, the addition of flame-retardant additives decreased the tensile strength, but this was ameliorated with the addition of FG. These new PU composite materials provide a promising strategy for producing polymer composites with flame retardation and smoke suppression for construction materials.
31
Cook, Peter, Yildiray Cinar, Guy Allinson, Charles Jenkins, Sandeep Sharma, Michael Soroka e Jo Ann Tan. "Enhanced gas recovery, CO2 storage and implications from the CO2CRC Otway Project". APPEA Journal 51, n. 2 (2011): 684. http://dx.doi.org/10.1071/aj10064.
Abstract (sommario):
Successful completion of the first stage of the CO2CRC Otway Project demonstrated safe and effective CO2 storage in the Naylor depleted gas field and confirmed our ability to model and monitor subsurface behaviour of CO2. It also provided information of potential relevance to CO2 enhanced gas recovery (EGR) and to opportunities for CO2 storage in depleted gas fields. Given the high CO2 concentration of many gas fields in the region, it is important to consider opportunities for integrating gas production, CO2 storage in depleted gas fields, and CO2-EGR optimisation within a production schedule. The use of CO2-EGR may provide benefits through the recovery of additional gas resources and a financial offset to the cost of geological storage of CO2 from gas processing or other anthropogenic sources, given a future price on carbon. Globally, proven conventional gas reserves are 185 trillion m3 (BP Statistical Review, 2009). Using these figures and Otway results, a replacement efficiency of 60 % (% of pore space available for CO2 storage following gas production) indicates a global potential storage capacity—in already depleted plus reserves—of approximately 750 Gigatonnes of CO2. While much of this may not be accessible for technical or economic reasons, it is equivalent to more than 60 years of total global stationary emissions. This suggests that not only gas—as a lower carbon fuel—but also depleted gas fields, have a major role to play in decreasing CO2 emissions worldwide.
32
Mendes, David, Pedro D. Gaspar, Fernando Charrua-Santos e Helena Navas. "Integrating TPM and Industry 4.0 to Increase the Availability of Industrial Assets: A Case Study on a Conveyor Belt". Processes 11, n. 7 (28 giugno 2023): 1956. http://dx.doi.org/10.3390/pr11071956.
Abstract (sommario):
As the global market becomes increasingly competitive and demanding, companies face the challenge of responding swiftly and efficiently to customer needs. To maintain a competitive advantage, organisations must optimise the usage of their assets. This study focuses on the critical role of maintenance management and presents a novel, cost-effective, and easily applicable model that integrates Industry 4.0 (I4.0) and Total Productive Maintenance (TPM) principles to enhance production processes. The proposed model incorporates a real-time monitoring system equipped with sensors, a gateway, and Internet of Things (IoT) services. These components enable data acquisition, transmission, storage, and visualisation through both mobile and fixed devices. The model’s effectiveness was validated through its implementation on a conveyor belt in a feed mill. The availability of the conveyor belt was around 89.5% before TPM implementation. After the implementation of TPM, it was possible to observe that the availability of the treadmill increased to 92.7% in a workweek of 105 h. On the other hand, it was possible to observe a considerable improvement in terms of the average time of each intervention, with a reduction of around 53%. Moreover, the model also facilitated improvements in the maintenance plan for the conveyor belt. Operators were trained to effortlessly comply with the new autonomous maintenance plan, enhancing operational efficiency. The joint application of I4.0 and TPM demonstrated significant advancements in maintenance management. The flexibility of the developed model allows for easy adaptation to monitor other condition parameters, enabling real-time decision-making for both the maintenance and production departments. This integrated approach holds the potential to drive process optimisation, ultimately contributing to improved productivity, cost-effectiveness, and competitiveness.
33
Momenikorbekandi, Atefeh, e Maysam Abbod. "Intelligent Scheduling Based on Reinforcement Learning Approaches: Applying Advanced Q-Learning and State–Action–Reward–State–Action Reinforcement Learning Models for the Optimisation of Job Shop Scheduling Problems". Electronics 12, n. 23 (23 novembre 2023): 4752. http://dx.doi.org/10.3390/electronics12234752.
Abstract (sommario):
Flexible job shop scheduling problems (FJSPs) have attracted significant research interest because they can considerably increase production efficiency in terms of energy, cost and time; they are considered the main part of the manufacturing systems which frequently need to be resolved to manage the variations in production requirements. In this study, novel reinforcement learning (RL) models, including advanced Q-learning (QRL) and RL-based state–action–reward–state–action (SARSA) models, are proposed to enhance the scheduling performance of FJSPs, in order to reduce the total makespan. To more accurately depict the problem realities, two categories of simulated single-machine job shops and multi-machine job shops, as well as the scheduling of a furnace model, are used to compare the learning impact and performance of the novel RL models to other algorithms. FJSPs are challenging to resolve and are considered non-deterministic polynomial-time hardness (NP-hard) problems. Numerous algorithms have been used previously to solve FJSPs. However, because their key parameters cannot be effectively changed dynamically throughout the computation process, the effectiveness and quality of the solutions fail to meet production standards. Consequently, in this research, developed RL models are presented. The efficacy and benefits of the suggested SARSA method for solving FJSPs are shown by extensive computer testing and comparisons. As a result, this can be a competitive algorithm for FJSPs.
34
Romera, Alvaro J., e Graeme J. Doole. "Optimising the interrelationship between intake per cow and intake per hectare". Animal Production Science 55, n. 3 (2015): 384. http://dx.doi.org/10.1071/an14424.
Abstract (sommario):
Production and profit in grazed systems remain inherently constrained by the fundamental trade-off between maximising individual herbage intake and pasture utilisation. The primary objective of this paper is to investigate the trade-off between herbage intake per cow and intake per hectare, from the perspective of economic optimisation, for an intensive pasture-based dairy farm in New Zealand (NZ). A detailed optimisation model of a dairy farm is applied, to allow the complex animal–plant–supplement dynamics underlying this relationship to be explicitly considered. Model output confirmed the existence of the fundamental inverse relationship between individual cow intake and herbage utilisation, which arises from the underlying biophysical dynamics within a grazing system, in the context of pasture-based NZ dairy farms. Results indicated that profitable management relies on increasing total pasture eaten (grazing plus pasture silage harvested on farm) through the use of a relatively high stocking rate and moderate levels of pasture intake per cow. Indeed, for 450 kg liveweight cows, optimal pasture intake per cow is 5 t dry matter (DM) per cow for per hectare intakes of 12–16 t DM/ha and 4.5 t DM/cow for a per hectare intake of 17 t DM/ha. Thus, a goal to maximise both individual intake and herbage utilisation in grazing systems is misinformed; it is the latter that is principally important to farm profit. Indeed, seeking to maximise both simultaneously is not possible, and trying to maximise individual intake can impose an enormous cost. However, while high herbage utilisation increases profit, this can also be associated with greater nutrient leaching, reinforcing the importance of considering the environmental impacts of grazing management.
35
Obeidi, Muhannad Ahmed, Paul Healy, Hasan Alobaidi, Declan Bourke e Dermot Brabazon. "Towards a Sustainable Laser Powder Bed Fusion Process via the Characterisation of Additively Manufactured Nitinol Parts". Designs 8, n. 3 (15 maggio 2024): 45. http://dx.doi.org/10.3390/designs8030045.
Abstract (sommario):
Is additive manufacturing (AM) a sustainable process? Can the process be optimised to produce sustainable AM parts and production techniques? Additive manufacturing offers the production of parts made of different types of materials in addition to the complex geometry that is difficult or impossible to produce by using the traditional subtractive methods. This study is focused on the optimisation of laser powder bed fusion (L-PBF), one of the most common technologies used in additive manufacturing and 3D printing. This research was carried out by modulating the build layer thickness of the deposited metal powder and the input volumetric energy density. The aim of the proposed strategy is to save the build time by maximizing the applied layer thickness of nitinol powder while retrieving the different AM part properties. The saving in the process time has a direct effect on the total cost of the produced part as a result of several components like electric energy, inert gas consumption, and labour. Nickel-rich nitinol (52.39 Ni at.%) was selected for investigation in this study due to its extremely high superplastic and shape memory properties in addition to the wide application in various industries like aerospace, biomedical, and automotive. The results obtained show that significant energy and material consumption can be found by producing near full dens AM parts with limited or no alteration in chemical and mechanical properties.
36
Pugh, T. A. M., A. R. MacKenzie, C. N. Hewitt, B. Langford, P. M. Edwards, K. L. Furneaux, D. E. Heard et al. "Simulating atmospheric composition over a South-East Asian tropical rainforest: Performance of a chemistry box model". Atmospheric Chemistry and Physics Discussions 9, n. 5 (16 settembre 2009): 19243–78. http://dx.doi.org/10.5194/acpd-9-19243-2009.
Abstract (sommario):
Abstract. Atmospheric composition and chemistry above tropical rainforests is currently not well established, particularly for south-east Asia. In order to examine our understanding of chemical processes in this region, the performance of a box model of atmospheric boundary layer chemistry is tested against measurements made at the top of the rainforest canopy near Danum Valley, Malaysian Borneo. Multi-variate optimisation against ambient concentration measurements was used to estimate average canopy-scale emissions for isoprene, total monoterpenes and nitric oxide. The excellent agreement between estimated values and measured fluxes of isoprene and total monoterpenes provides confidence in the overall modelling strategy, and suggests that this method may be applied where measured fluxes are not available. The largest contributors to the optimisation cost function at the point of best-fit are OH (41%), NO (18%) and total monoterpenes (16%). Several factors affect the modelled VOC chemistry. In particular concentrations of methacrolein (MACR) and methyl-vinyl ketone (MVK) are substantially overestimated, and the hydroxyl radical [OH] concentration is substantially underestimated; as has been seen before in tropical rainforest studies. It is shown that inclusion of dry deposition of MACR and MVK and wet deposition of species with high Henry's Law values substantially improves the fit of these oxidised species, whilst also substantially decreasing the OH sink. Increasing [OH] production arbitrarily, through a simple OH recycling mechanism, adversely affects the model fit for volatile organic compounds (VOCs). Given the constraints on isoprene flux provided by measurements, a substantial decrease in the rate of reaction of VOCs with OH is the only remaining option to explain the measurement/model discrepancy for OH. A reduction in the isoprene + OH rate constant of 50–70% is able to produce both isoprene and OH concentrations within error of those measured. Whilst we cannot rule out an important role for missing chemistry, particularly in areas of higher isoprene flux, this study demonstrates that the inadequacies apparent in box and global model studies of tropical VOC chemistry may be more strongly influenced by representation of detailed physical and micrometeorological effects than errors in the chemical scheme.
37
Pugh, T. A. M., A. R. MacKenzie, C. N. Hewitt, B. Langford, P. M. Edwards, K. L. Furneaux, D. E. Heard et al. "Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model". Atmospheric Chemistry and Physics 10, n. 1 (14 gennaio 2010): 279–98. http://dx.doi.org/10.5194/acp-10-279-2010.
Abstract (sommario):
Abstract. Atmospheric composition and chemistry above tropical rainforests is currently not well established, particularly for south-east Asia. In order to examine our understanding of chemical processes in this region, the performance of a box model of atmospheric boundary layer chemistry is tested against measurements made at the top of the rainforest canopy near Danum Valley, Malaysian Borneo. Multi-variate optimisation against ambient concentration measurements was used to estimate average canopy-scale emissions for isoprene, total monoterpenes and nitric oxide. The excellent agreement between estimated values and measured fluxes of isoprene and total monoterpenes provides confidence in the overall modelling strategy, and suggests that this method may be applied where measured fluxes are not available, assuming that the local chemistry and mixing are adequately understood. The largest contributors to the optimisation cost function at the point of best-fit are OH (29%), NO (22%) and total peroxy radicals (27%). Several factors affect the modelled VOC chemistry. In particular concentrations of methacrolein (MACR) and methyl-vinyl ketone (MVK) are substantially overestimated, and the hydroxyl radical (OH) concentration is substantially underestimated; as has been seen before in tropical rainforest studies. It is shown that inclusion of dry deposition of MACR and MVK and wet deposition of species with high Henry's Law values substantially improves the fit of these oxidised species, whilst also substantially decreasing the OH sink. Increasing OH production arbitrarily, through a simple OH recycling mechanism , adversely affects the model fit for volatile organic compounds (VOCs). Given the constraints on isoprene flux provided by measurements, a substantial decrease in the rate of reaction of VOCs with OH is the only remaining option to explain the measurement/model discrepancy for OH. A reduction in the isoprene+OH rate constant of 50%, in conjunction with increased deposition of intermediates and some modest OH recycling, is able to produce both isoprene and OH concentrations within error of those measured. Whilst we cannot rule out an important role for missing chemistry, particularly in areas of higher isoprene flux, this study demonstrates that the inadequacies apparent in box and global model studies of tropical VOC chemistry may be more strongly influenced by representation of detailed physical and micrometeorological effects than errors in the chemical scheme.
38
Utomo, Oscar, Muditha Abeysekera e Carlos E. Ugalde-Loo. "Optimal Operation of a Hydrogen Storage and Fuel Cell Coupled Integrated Energy System". Sustainability 13, n. 6 (22 marzo 2021): 3525. http://dx.doi.org/10.3390/su13063525.
Abstract (sommario):
Integrated energy systems have become an area of interest as with growing energy demand globally, means of producing sustainable energy from flexible sources is key to meet future energy demands while keeping carbon emissions low. Hydrogen is a potential solution for providing flexibility in the future energy mix as it does not emit harmful gases when used as an energy source. In this paper, an integrated energy system including hydrogen as an energy vector and hydrogen storage is studied. The system is used to assess the behaviour of a hydrogen production and storage system under different renewable energy generation profiles. Two case studies are considered: a high renewable energy generation scenario and a low renewable energy generation scenario. These provide an understanding of how different levels of renewable penetration may affect the operation of an electrolyser and a fuel cell against an electricity import/export pricing regime. The mathematical model of the system under study is represented using the energy hub approach, with system optimisation through linear programming conducted via MATLAB to minimise the total operational cost. The work undertaken showcases the unique interactions the fuel cell has with the hydrogen storage system in terms of minimising grid electricity import and exporting stored hydrogen as electricity back to the grid when export prices are competitive.
39
Sievers, M., A. Ried e R. Koll. "Sludge treatment by ozonation Ð evaluation of full-scale results". Water Science and Technology 49, n. 4 (1 febbraio 2004): 247–53. http://dx.doi.org/10.2166/wst.2004.0275.
Abstract (sommario):
Ozonation of industrial and sewage sludge is a suitable process for minimizing the sludge production of activated sludge processes. The ozonation has the advantage for complete oxidation of volatile suspended solids (VSS) of combining partial sludge oxidation with subsequent biological oxidation. This paper describes the evaluation of two full-scale sewage sludge ozonation investigations for subsequent aerobic stabilisation as well as for subsequent anaerobic stabilisation compared to different sludge treatment processes. For both the anaerobic and aerobic application, sludge liquefying by release of 110 and 160 mg COD per g total suspended solids (TSS) has been reached at specific ozone consumption of 0.03 and 0.06 kg O3 per kg TSS, respectively. The subsequent biological treatment has reached a mass reduction of 20-35% for the aerobic and 19% for the anaerobic stabilisation. For both applications the specific ozone consumption was about 0.05 kg O3 per kg TSS to be treated. A comparison with mechanical and thermo-chemical sludge mass reduction methods shows that the mass reduction potential of ozonation is presently higher. Even though costs for sludge ozonation are higher compared to other methods, the optimisation potential for cost reduction of sludge ozonation is obvious from the results presented in this paper.
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Dębowski, Marcin, Joanna Kazimierowicz, Aneta Ignaciuk, Sandra Mlonek e Marcin Zieliński. "Application of Recycled Filling to Improve the Purification Performance of Confectionery Wastewater in a Vertical Anaerobic Labyrinth Flow Bioreactor". Energies 17, n. 11 (24 maggio 2024): 2551. http://dx.doi.org/10.3390/en17112551.
Abstract (sommario):
Anaerobic wastewater treatment is, in many cases, a justified alternative to typical activated sludge processes, from a technological, economic, and ecological point of view. The optimisation of fermentation reactors is primarily concerned with increasing the biodegradation of organic compounds and biogas production, as well as improving efficiency in the removal of nitrogen and phosphorus compounds. The aim of the research was to determine the impact of using low-cost recycled filling on the efficiency of treating real confectionery wastewater in a vertical anaerobic labyrinth flow bioreactor. The experiments focused on selecting the organic loading rate that would allow for the effective biodegradation and removal of pollutants, as well as the efficient production of biomethane. It was found that the tested reactor can operate efficiently at a maximum organic loading rate (OLR) of 7.0–8.0 g of chemical oxygen demand (COD)/L·d. In this OLR range, high efficiency was guaranteed for both wastewater treatment and biogas production. However, increasing the OLR value to 8.0 g COD/L·d had a significant negative effect on the methane (CH4) content in the biogas. The most efficient variants achieved a biodegradation efficiency of around 90% of the organic compounds, a CH4 content of over 70% in the biogas, and a biogas yield of over 400 L/kg of COD removed. A significant influence of the applied OLR on the ratio of free organic acids (FOS) to total alkaline capacity (TAC) and pH was observed, as well as a strong correlation of these indicators with the specific biogas yield and CH4 content. The application of a solution based on the use of a hybrid system of anaerobic granulated sludge and an anaerobic filter resulted in an efficient treatment process and an almost complete elimination of suspensions from the wastewater.
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Hermes, M. "Airborne sound insulation of single-leaf partitions under hygric load". Journal of Physics: Conference Series 2069, n. 1 (1 novembre 2021): 012161. http://dx.doi.org/10.1088/1742-6596/2069/1/012161.
Abstract (sommario):
Abstract In buildings of all types the use of single-leaf partitions are recommended, not least for reasons of cost efficiency and possible resource optimisation. In addition to the familiar building physics topics they play also a particularly important role in noise protection. Numerous factors influence the acoustic properties of single-leaf, plate-shaped and dry partitions. These include the mass, the bending stiffness, the position of the critical frequency and the total loss factor of the partition as well as the stimulating frequency of the airborne sound, the sound incidence angle or the characteristic impedance of the air. Each mineral wall-building material has its own product-specific pore structure. In the usual calculation of the airborne sound insulation of single-leaf, airtight and dry partitions, this has so far not been taken into account. It is precisely in these building material pores that a hygrothermal, continuous adjustment of the moisture content takes place in addition to the production-related water quantities. This changes the mass of the building component and thus the airborne sound insulation of the wall. In addition to this well-known mass effect, a further mechanism, which has not yet been considered, increases airborne sound insulation: the smaller the pore sizes in the building material, the greater the mechanical forces caused by stored pore water. The existing equations for airborne sound insulation do not take these effective forces into account and must therefore be extended. The wall building material is considered as a porous medium with solid and fluid components. The new calculation approach allows the calculation of the airborne sound reduction index for single-leaf partitions under hygric load for saturated and partially saturated moisture conditions with high accuracy. The calculation results provide valuable information for the planning and product development of new building materials.
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Vasilchenkо, A. V., S. V. Prakh e M. E. Podgornaya. "Features and dynamics of species composition of entomoacarosystems in plum orchards". Horticulture and viticulture, n. 3 (27 luglio 2023): 45–51. http://dx.doi.org/10.31676/0235-2591-2023-3-45-51.
Abstract (sommario):
The long-term analysis of the entomocomplex of plum orchards, carried out in Krasnodar Territory, revealed variations in the quantitative composition of entomofauna of harmful species and the level of their harmfulness. It was established that, in the period from 2005 to 2021, the rotation of dominant and secondary species occurred. The main species included plum Grapholitha funebrana Treitschke and oriental Grapholitha molesta Busck fruit moths, plum black Haploca minuta Christ. and yellow Hoplocampa flava L. sawflies, plum aphid Hyalopterus pruni Geoffr. and twospotted spider mite Tetranychus urticae Koch. Associated species included plum gall Acalitus phloeocoptes (Nal.) and hawthorn Tetranuchus viennensis Zacher. mites, fruit-tree Tibicina haematodes Scopoli and citrus flatid Metcalfa pruinosa (Say) planthoppers and leaf roller moths of Tortricidae family. The group characterised by a limited distribution area includes the Californian Quadraspidiotus perniciosus Comst. and Turanian Diaspidiotus prunorum Laing. scales, plum Sphaerolecanium prunastri Fonsc and European brown Parthenolecanium corni Bouche. scales, seed wasps Eurytoma amygdali End., brown marmorated stinkbug Halyomorpha halys (Stål) and secondary insects (unequal bark beetle Xyleborus dispar F., fruit tree bark beetle Scolytus rugulosus (P.W.J. Müller), wood leopard moth Zeuzera pyrina L). When considering the structure formation of phytophage complex according to phylogenetic specialization, taking into account trophic relationships, it was established that the proportion of polyphages is 2.5 times higher than that of oligophages and 8.5 times higher than that of monophages from the total number of registered pest species. In the past decade, a reduction of pesticide load in plum agrocenoses has been observed due to the wider use of agrotechnical methods and the inclusion of bioregulatory and biological insecticides into protection systems, which contributed to the preservation and increase of beneficial fauna. Entomophages constitute 7–10% of the total number of entomoacrocenosis dominated by Hymenoptera and Coleoptera classes and mites of Acari subclass. The long-term monitoring of species composition, rotation of dominant and secondary pest species and entomophages, variations in their number and harmfulness, seasonal dynamics, trophic relationships of plum entomoacrocenosis under varying environmental conditions and increasing intensification of agricultural production expand the possibility of phytosanitary optimisation strategy of perennial agrocenoses in the south of Russia. This contributes to the preservation of regional biodiversity, as well as to the stable production of high-quality ecologically safe products with minimal negative impact on the environment.
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Borysenko, Volodymyr, e Dmytro Borysenko. "Optimisation of production and modelling of production costs in farms". Ekonomika APK 31, n. 1 (29 febbraio 2024): 10–18. http://dx.doi.org/10.32317/2221-1055.202401010.
Abstract (sommario):
A significant area of improvement of the economic efficiency of agricultural enterprises, especially in the context of martial law, is to optimise production and use of resource potential. The purpose of this study was to develop scientific and practical recommendations for optimising the production activities of farms. The study employed the following methods: system analysis and synthesis to determine the reserves of the types of resources involved; economic-mathematical modelling and optimisation to determine best solutions; analytical-calculation method to calculate production indicators; correlation and regression analysis to determine the dependence of milk production costs on resource consumption; graphical method and extrapolation to find the values of the regression function. The principal stages and features of building an economic-mathematical model for optimising the resource potential of enterprise were identified. The model was used to analyse data, identify reserves of resource potential, find an optimisation solution for product sales volumes using the Solution Search spreadsheet tool, and adopt a strategy for improving economic efficiency. The study offered a solution for the economic and mathematical modelling of the best structure of production of a farm, which factors in the available production resources. The modelling found that the maximum income can be obtained by redistributing the production volumes of certain types of products and, accordingly, the resources for their production, considering the standard costs of production per unit of product, prices for products and resources. Using the modelling, the study obtained a regression dependence of the cost of milk produced in household farms on the cost of feed, labour costs, wages, and the number of cows. The study found the impact of certain types of resources on the production cost and builds the corresponding graphical dependencies. The practical value of the findings of this study lies in the possibility of using the recommendations directly by members of farms in planning, organising production activities, and optimising the use of resource potential
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Fafandjel, Nikša, Albert Zamarin e Marko Hadjina. "Shipyard production cost structure optimisation model related to product type". International Journal of Production Research 48, n. 5 (28 gennaio 2009): 1479–91. http://dx.doi.org/10.1080/00207540802609665.
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Parekh, Mayur, AbdulAziz Ali, Zulfiqur Ali, Simon Bateson, Fathi Abugchem, Leon Pybus e Christopher Lennon. "Microbioreactor for lower cost and faster optimisation of protein production". Analyst 145, n. 18 (2020): 6148–61. http://dx.doi.org/10.1039/d0an01266a.
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Anil, Rana, Ajit Verma e A. S. Srividya. "Optimisation of production machine scheduling using a two level mixed optimisation method". Yugoslav Journal of Operations Research 20, n. 2 (2010): 197–212. http://dx.doi.org/10.2298/yjor1002197a.
Abstract (sommario):
This paper presents an application of a two level mixed optimization method on a machine scheduling problem of a government owned machine shop. Where evolutionary algorithm methods are suitable for solving complex, discrete space, and non-linear, discontinuous optimization problems; classical direct-search optimization methods are suitable and efficient in handling simple unimodal problems requiring less computation. Both methods are used at two levels, the first level decides which machines to be used for the machining operations and how much overtime (at extra cost) to be allotted to each work order, the second level decides for which operation and on which day the overtime should be allotted so as to attain its maximum benefit. A sample problem has been solved by using the above methods and a range of non-dominated solutions have been presented in a tabular form to enable the production manager to choose his options based on the given criticality of the work order.
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Chagwiza, Godfrey. "Cost-Effective Forage and Browse Legume Feed for Dairy Production: An Optimisation Approach Using Jaya Optimisation Algorithm". Advances in Agriculture 2022 (18 luglio 2022): 1–5. http://dx.doi.org/10.1155/2022/5838723.
Abstract (sommario):
Livestock feed mix or feed choice decision-making is encountered by farmers in their daily operations. Livestock feed choice and mixing is emerging as a key research area considering the impact of climate change and emergence of new technology. Smallholder dairy farmers are usually capital constrained and hence a need to investigate cost-effective feed choice that maximises profit. A study to investigate the cost-effective feed among forage and browse legumes was conducted among smallholder dairy farmers in Zimbabwe. An optimisation problem was formulated with the objective of maximising profit by selecting the most cost-effective feed among forage and browse legumes. Secondary data are used to solve the optimisation problem by implementing the Jaya optimisation algorithm. Results show that grain crop silage is the best feed choice resulting in a maximum profit of $ 66.00 per day per farmer. Further research can be directed towards investigating the effect of combining the next best feed, quality hay, and grain crop silage for profit contribution.
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Mahmood, Farrukh, e Haider Ali. "Energy-Cost Optimisation in Water-Supply System". Pakistan Development Review 52, n. 4I (1 dicembre 2013): 437–46. http://dx.doi.org/10.30541/v52i4ipp.437-446.
Abstract (sommario):
Water, being the basic requirement of life, is important to all living organism, human health and food production. A positive correlation between economic growth and rate of water utilisation has also been observed in a growth model with water as a productive input for private producers [Barbier (2004)]. In addition, high per-capita consumption (PCC) of water is regarded as an indicator of the level of economic development where per-capita water consumption is defined as the average of water consumed by a person in a day. The declining availability of water supply, mainly due to global climate change, is one of the important issues faced by many developing countries at the present time. It is estimated that nearly two third of nations across the globe will experience water stress by 2025.1 Thus, the safety and availability of clean water is an on-going concern within the global village
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Cheshire, David, Robert Edmondson e Paul Savidge. "Façade Optimisation Using a Point Equilibrium Methodology". Key Engineering Materials 572 (settembre 2013): 601–4. http://dx.doi.org/10.4028/www.scientific.net/kem.572.601.
Abstract (sommario):
Modern, organic shaped, building façades are often created by joining together hundreds of flat panels, resulting in high production complexity. To reduce cost it is important to design the façade using the fewest possible unique panels. Each unique panel increases design and production times so using many repeated panels enables batch production, lowering cost. To optimise the panel layout with the fewest unique panels a ‘point equilibrium’ algorithm has been developed to position the corners of the panels (nodes) on a parametric surface. In the developed theory a set of hypothetical, electrically charged particles is randomly placed upon the façade surface and allowed to repel each other. They eventually settle into an equilibrium position, with similar distances between adjacent nodes and hence produce a large number of similar triangles. An example of a façade demonstrating the practicability of this technique for constructing panel layouts is given.
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Rybakov, Dmitriy S. "Total cost optimisation model for logistics systems of trading companies". International Journal of Logistics Systems and Management 27, n. 3 (2017): 318. http://dx.doi.org/10.1504/ijlsm.2017.084469.