Investment Payback Research Articles

Efficiency of gas preparation technology using a block drying plant

The object of research is the technology of gas drying using a mobile block installation. The task to ensure compliance of the composition of natural gas with the values of a number of basic characteristics before its supply to main pipelines has been solved. The results of a complex analysis of the gas preparation technology of the deposit, which is located in an agricultural area and is at a late stage of exploitation, are reported. It was established that in order to ensure the supply of conditioned gas to the system of main gas pipelines under the conditions of low gas pressures, the construction of gas treatment plants is required, first of all, for its drying. The method of ensuring gas quality considered in the current paper involves the use of a block-type gas drying installation as part of a low-temperature separation installation and a source of artificial cold. As the latter, it is envisaged to use a freon-refrigerating unit. The study shows that the proposed block gas drying units can be unified for different gas productivity and are characterized by relatively low capital and operating costs. The main advantages of the introduction of gas preparation block installations and the scheme of connecting the installation to the existing line are presented. Based on the results of the economic efficiency indicators, it was established that the use of a block gas drying unit is a profitable project with the value of the accumulated reduced free cash flow of almost 843 thousand conditional units; the investment payback period is 3 years. The results could be effectively used in the gas distribution sector, provided that the gas is extracted from a field close to exhaustion, which is characterized by low reservoir pressures

Modelling Framework for Reducing Energy Loads to Achieve Net-Zero Energy Building in Semi-Arid Climate: A Case Study

Buildings consume a significant 40% of global energy, where, reducing the building energy consumption to a minimum, virtually zero, has become a thriving research area. Accordingly, this research aimed to determine and portray the huge potential of energy conservation in existing structures by making a retrofit at relatively low costs in finance strained economies. A walk-through of the survey of energy consuming appliances determined the energy consumption based on the power rating; the appliances were then virtually replaced and the reduced energy consumption was determined in terms of the cooling loads. Modelling these intervention using the hourly analysis program (HAP) showed significantly positive results. The pre- and post-retrofit model analysis of an institutional building in Pakistan exhibited significant potential for reducing the cooling load of 767 kW (218 TON) to 408 kW (116 TON) with an investment payback period of 2.5 years. The additional benefit is the reduced greenhouse gas (GHG) emissions which reduce the overall energy requirements. The study continues with the design of a solar energy source using the system advisor model (SAM) for the reduced energy demand of a retrofitted building. It is then concluded that using the available area, a solar energy source with a capital payback period of 5.7 years would bring an institutional building within its own energy footprint making it a net-zero building, since it will not be consuming energy from any other source outside of its own covered area. The study has the limitation to exposure and climate related conditions. In addition, the decline in heating and cooling loads represents model values which may vary when calculated after an actual retrofit for the same structure due to any site related issues.

Economic analysis of gas turbine/supercritical carbon dioxide combined cycle under different cycle configurations

S–CO2 cycle systems have many advantages, but coupling with gas turbine power generation systems has been poorly studied. Considering the huge cold energy of LNG, it can not only be used as coolant in combined cycle system, but also the natural gas after heat exchange can be used as fuel input for combined cycle and the remaining part can be supplied to city users. In this paper, ten combined cycles were proposed for both water and LNG media, with/without intercooling process and the number of flue gas heat exchangers. A detailed analysis of the investment cost, operating income and payback period of the cycle power system is carried out by selecting the appropriate cost equation. The results show that increasing the number of flue gas heat exchangers, increasing the number of coolers and using LNG as the cooling medium can improve the energy efficiency. Cascade 9 (GT/two flue gas heat exchangers intercooled LNG tandem combined cycle system) has a maximum annual benefit of 19.59 (106$); a maximum cumulative benefit (20 years) of 204.78 (106$) for Cascade 9; Cascade 9 (GT/two flue gas heat exchangers intercooled LNG tandem combined cycle system) has a minimum payback period of 7.81 years.

Comprehensive Characterization of Energy Saving and Environmental Benefits of Campus Photovoltaic Buildings

The development of campus photovoltaic buildings is a promising way to solve the problem of high energy consumption in colleges and universities. However, comprehensive study on their energy saving and environmental benefits is still insufficient. In this study, a theoretical model of a photovoltaic building roof system was preliminarily built, and the main factors affecting the power generation of campus photovoltaic buildings were analyzed. Furthermore, an experimental test platform for the campus photovoltaic building system was built, and a dynamic grid-connected strategy of “spontaneous self-use, surplus electricity connected to the grid” was creatively proposed, which points out that the grid connection rate in winter and summer vacations are about 15% and over 40%, respectively, and the annual grid connection rate is 25%. The result shows that the electricity input of the campus photovoltaic building can bear nearly 30% of the school’s annual electricity supply, which reduces the comprehensive energy consumption per unit area and per capita comprehensive energy consumption of the campus by more than 20%. The economic and environmental benefits of the 130,000 square meter campus photovoltaic building in the article are 38.8 million CNY and 20.12 million CNY, respectively, and the static investment payback period is about 7 years. The results show considerable reference value to the upgrading of campus photovoltaic buildings.

Study on optimal allocation of solar photovoltaic thermal heat pump integrated energy system for domestic hot water

In recent years, solar photovoltaic thermal heat pump has become a highly concerned near-zero carbon energy technology for domestic hot water. In order to facilitate the optimal configuration design of the system for domestic hot water, following studies were carried out in this paper: Firstly, the photovoltaic thermal heat pump integrated energy system was established and the operation study of the system was carried out. During the operation, the average coefficient of system heating performance was 2.76 in winter, 3.55 in transition season and 4.10 in summer. Afterwards, the prediction model of system operation performance was established and hourly system performance prediction of the system in the whole year was conducted. Then, the system for domestic hot water with a total installed photovoltaic capacity of 1 MW was taking as a case study to establish the calculation model. Finally, the optimal allocation of the system was carried out with the goal of minimizing the dynamic investment payback period, then the standard cell method was proposed to facilitate the optimal allocation design. The results showed that the minimum dynamic investment payback period of the system was 3.9 years and the daily hot water supply of the standard cell was 9.2tons.

PAYBACK CALCULATION REFINEMENT OF INDUSTRIAL ROBOT APPLICATIONS

The paper focuses on describing and applying a refined method of investment payback calculation related to industrial robot applications. Industrial robots play an important role in modern manufacturing companies, therefore it is important to precisely determine the investment payback of robot applications. In the first part of the paper, we introduce payback calculation theory in general and the current approaches to payback calculation of robot applications in practice. Subsequently, we point out that current approaches seem insufficient due to tracking only a limited number of costs and savings. Subsequently, we attempt to identify all identifiable costs and savings related to robotic applications, then we present a refined method to determine the payback of robot applications more precisely. The method is then applied in a case study performed in an industrial enterprise. Finally, we evaluate how significantly this refined method differs from the calculation used in practice and these findings are summarised.

The influence of deep loosening on the ecological and meliorational state of drained mineral soils

The existing problems of energy, water, and food crises and climate changes determine the need to implement appropriate adaptive measures to improve the ecological and reclamation state of drained mineral soils. For the application of deep loosening of the soil as an adaptive agromelioration measure, a transition from traditional crack loosening of the soil and strip loosening of the soil to improved technologies of continuous layer-by-layer loosening of the soil based on energy-efficient and moisture-regulating principles is proposed. Their comparative evaluation according to the main indicators of overall efficiency was carried out on drained mineral soils of a representative object in the Western Polissia zone of Ukraine. According to the results of the evaluation of various technologies of deep soil loosening, it was determined that the technologies and technical means of continuous deep loosening of the soil have an advantage in all main indicators: agrotechnical, water-physical, energy, technological, ecological, and economic. In particular, the moisture availability of the soil increased by 27 % due to better accumulation of atmospheric precipitation, the yield of cultivated crops also increased by 20-30 %, and the aftereffect period increased to 4 years. This is a cost-effective and investment-friendly adaptive measure to ensure a satisfactory ecological and reclamation state of drained mineral soils (with an investment payback of 1 year). This provides modern principles of adaptive land use in changing climatic conditions and can be an effective alternative to expensive reconstruction and modernization of existing drainage systems.

An Empirical Investigation into the Feasibility of a Smoked Fish Enterprise Utilising Liquid Smoke Technology in Central Maluku Regency

The purpose of this research is to analyze the feasibility of liquid smoked fish businesses, especially tuna and skipjack, by utilizing liquid smoke technology in Tulehu Village and Waai Village, Central Maluku Regency. To find out whether this liquid smoked fish business is worth running or not. The research used a survey method with direct interview techniques with liquid smoked fish business actors in Tulehu Village and Waai Village regarding the liquid smoked fish production process, marketing, sales and profits obtained. The data obtained was then analyzed for business feasibility from a financial aspect. The analysis technique used is using investment criteria including: Payback Period, Net Present Value, Internal Rate of Return (IRR), and Profitability Index as well as investment risk using sensitivity analysis. The results of this research show that the liquid smoked fish business in Tulehu village and Waai village is considered feasible because the financial aspect is considered to meet the investment assessment criteria, the rate of return on investment (Payback Period) is faster than the project plan, namely 5 years, the Net Present Value has positive value, the Internal Rate of Return is above the expected profit level, and the Profitability Index /Benefit Cash Ratio Ratio is greater than oneKeywords: Feasibility of liquid smoked fish business, Payback Period, Net Present Value, Internal Rate of Return, Profitability Index /Benefit Cash ratio Ratio is greater than one

A Nash bargaining model for energy sharing between micro-energy grids and energy storage

Micro-energy grids (MEGs) play a crucial role in achieving diverse energy utilization and promoting low-carbon economies. However, the intermittent nature of distributed generation and the inter-coupling of multiple energy types pose challenges to efficient energy management in MEGs. In this paper, we propose a novel Nash bargaining game-based electricity-gas energy-sharing model for MEGs. Our model incorporates bus structure-based energy storage combined with power-to-gas technology, which enables MEGs to establish an integrated electricity-gas energy-sharing network. This network facilitates both direct sharing and buffered sharing of energy, addressing the limitations of intermittent generation and enhancing overall energy management. To address the issue of computational complexity, the proposed Nash bargaining game model is decomposed into two sub-problems: social energy cost minimization and benefits sharing. Through optimization, we obtain optimal energy-sharing profiles and energy-sharing payments. Moreover, we consider the investment payback period of energy storage and adjust the initial benefit-sharing results accordingly. Case studies demonstrate that our model significantly improves economic performance, increasing the self-sufficiency ratio of MEGs to 64% and energy storage efficiency to 63% compared to operating independently. Additionally, the multiplayer Nash bargaining game model facilitates Pareto optimal benefits for MEGs and energy storage by capturing their interactive dynamics.

Hybrid Power Retrofitting Study for a Platform Supply Vessel

This paper takes a platform supply vessel as the parent vessel and introduces its power system configuration and working conditions; to meet the requirements of carbon emissions reduction and improve economic efficiency, a preliminary program of marine hybrid power retrofitting of diesel generator sets assisted with Lithium battery module is proposed on the base of analyzing its working conditions, the fuel consumptions and carbon emissions are compared between before and after the retrofitting, etc. According to the calculation results, the paper concludes that the investment payback period of the refitting is about 6.38 years, and this refitting will have good economic benefits and social benefits.

Improving performance of air conditioning system by using variable-circuit heat exchanger: Based on the Chinese APF standard

For finned-tube heat exchangers, owing to the extremely different refrigerant pressure drop characteristics between condensation and evaporation processes, the optimum refrigerant circuits of these two conditions are different. However, for a typical heat pump type air conditioner, refrigerant circuit of the conventional heat exchanger (CHX) is fixed no matter what operation condition is conducted. To solve this problem, a modified variable-circuit heat exchanger (VCHX) is developed for air conditioner outdoor unit applications. The VCHX, for which the refrigerant circuit can be easily switched by using a globe valve, could provide better matching characteristics between refrigerant circuit and operation condition variations. With a developed simulation model, refrigerant circuit of the VCHX is optimized by using the entropy generation minimization theory. Then, comparative experimental works were conducted to investigate the performance of VCHX and CHX systems in detail. Experimental results show that the presented VCHX is more suitable for high heating capacity and low cooling capacity applications. Based on the Chinese APF (annual performance factor) Standard, the VCHX system yields 6.5% higher APF value over CHX system. Significantly, economic analysis indicates that the investment payback period of VCHX system is 1.46 year, which is much lower than the designed lifetime of a residential air conditioner. In general, the VCHX technique has a great application potential for improving the overall performance of a heat pump type air conditioner.

Analisis Kelayakan Finansial Dalam Peningkatan Kapasitas Kandang Di Usaha Peternakan Ayam Broiler Andien

The Broiler Chicken business owned by Andien, belonging to Mrs. Tri Winarti, initially operated with a capacity of 12,000 chickens and planned to expand to 24,000 chickens. This study aims to assess the sustainability of the development of Andien's Broiler Chicken farm to 24,000 chickens from a financial perspective. Financial analysis was conducted through calculations of Net Present Value (NPV), Benefit Cost Ratio (BCR), Internal Rate of Return (IRR), and Payback Period (PP). From the calculation results, it can be concluded that the expansion of Andien's Broiler Chicken business from 12,000 chickens to 24,000 chickens is a viable step based on the scenario calculations. The Payback Period (PP) is 1.31 periods, indicating a quick payback of investment as PP is less than 12 periods. The calculation results show an NPV value of Rp 4,936,714,867 using a 6% discount rate (based on the 2023 BRI KUR interest rate), and if using a 7% discount rate (based on the 2023 Mandiri KUR interest rate), the NPV would be 4,633,045,331. The presence of a positive NPV indicates the viability of this business development. The calculated IRR value reaches 22.26%, exceeding the 6% discount rate. The feasibility of the business is also supported by a BCR value of 1.09, where a ratio above 1 indicates the viability of the business.

BIPV Generation Efficiency Optimal Scheme—— Take Jiangning District of Nanjing City for Example

Building Integrated photovoltaic (BIPV) is more and more applied to the construction field with its advantages of being close to the load center, saving urban land and building materials. Especially under the current goal of 'carbon peak' and 'carbon neutrality', the integration of photovoltaic buildings is one of the important ways to achieve the effective application of renewable energy in buildings. But at present, the lack of relevant application cases of the technology, many owners interested in BIPV have remained on the sidelines. This paper mainly focuses on the economic and environmental benefit evaluation of the roof and curtain wall system of BIPV. By comparing the economic benefits and investment payback period, the owners provide the optimal investment plan, and analyzes the significance of 'two-carbon policy' by calculating the environmental benefits of BIPV. In this paper, Jiangning District of Nanjing city is taken as the pilot object to analyze the benefit of BIPV, and proposed the optimal design strategy of building photovoltaic integration suitable for this area through the benefit comparison of different schemes. In the roof and curtain wall benefit evaluation when we use the photovoltaic garden analysis site for solar radiation estimates, and then get the whole life cycle of photovoltaic system capacity, as the basis of economic benefit evaluation, then through the query related data to save the total coal as the basis of environmental benefit evaluation, combined with the project investment payback period, economic benefits and environmental benefits of comprehensive evaluation of the final plan. Through the above economic benefits and environmental benefits data comparison, photovoltaic roof has more investment value than photovoltaic curtain wall in both economic and environmental aspects. Taking Jiangning District of Nanjing city as an example, this paper illustrates the broad prospect of BIPV, and also provides a relatively clear data support and case reference for the promotion of BIPV nationwide in the future.

Exergy-based techno-economic and environmental assessments of a proposed integrated solar powered electricity generation system along with novel prioritization method and performance indices

This study focused on the two important gaps in the literature. The first is solar energy- powered electricity generation in a more economical way via the integration of flat plate solar collector (FPSC), an Organic Rankine Cycle (ORC), and an absorptional heat transformer (AHT) system. Another gap is advanced exergy analysis of the AHT cycle/ORC process based on renewable energy integration to reveal clues for improving the system. To close these gaps, a novel system including a lithium bromide AHT cycle-ORC with a FPSC system application was proposed in this study. In this proposed system, the temperature of the heat source for the ORC system was upgraded via an integration of the AHT and FPSC cycles. The main components of the AHT cycle are the condenser (ABScon), refrigerant cycle pump (P1), evaporator (EV), absorber (ABS), solution heat exchanger (SHX), absorbent cycle pump (P2), expansion valve (V), generator (Gen), ORC turbine (ORCT) and ORC condenser (ORCcon). To demonstrate the electricity production from solar energy in a more economical way thanks to the proposed system, a comparison was made with similar-scaled existing solar power plants. The results supported the main purpose of this study. The annual electricity production with the proposed system was calculated as 2601 MWh, with initial investment cost and payback period values of US$3.924 million and 4.531 years, respectively. The conventional and advanced exergy, exergoeconomic, environmental impact, and sustainability analyzes were also performed. Based on these, the novel performance parameters and prioritization method were proposed to assess the improvement potential of the system. The results indicated that SHX and FPSC had the highest exergy destruction rates (EDRs) of 23.711% and 21.849% over 5853.89 kW due to the stronger thermal and chemical reactions. Similarly, Gen, FPSC, and SHX had the highest ED cost rates (CRs) of 67.59%, 59.09%, and, 47.98%, respectively. Gen, V, and ORCcon were higher contributors to the exergy destruction rates of almost all the components. However, these showed an adverse manner for irreversibility activities. So, the temperatures of Gen and ORCcon should be optimized carefully. ABScon, P2, P1, ABS, Gen, ORCT, and ORCcon had high development priority to improve the whole system.

Study on Energy Flow Characteristics of Solar–Gas Combined Heating System for Settling Tank of Oilfield

Heating furnaces fueled by fossil fuels are commonly utilized in oilfields to provide heat to the settling tank, which heats the layer of crude oil. However, this traditional heating method consumes a significant amount of oil and gas resources, resulting in low energy utilization and environmental pollution. As the water content of the extracted crude oil increases over time, the operating costs of the settling tanks also continue to increase. Therefore, it is crucial to develop and implement clean and efficient heating technologies to facilitate the efficient operation of settling tanks. This paper proposes a solar–gas combined heating technology for settling tanks. A simulation model for the solar–gas combined heating system for the settling tank is constructed, considering the overall perspective of the system. The simulation model analyzes the impact of the control strategy for the oil collection period of the settling tank on the system performance. This analysis covers various aspects including the heat collection of the solar collector, the heat supply of the gas boiler, and the heat storage and release of the phase-change heat storage tank. The results demonstrate that when the oil collection cycle is Scheme E (4:00–8:00), the collector achieves the highest annual cumulative heat collection, the gas boiler provides the lowest annual total heat supply, and the phase-change heat storage tank exhibits the highest heat storage and release efficiency. Over the course of the system’s 15 year service life, the settling tank solar–gas combined heating system saves 727,988.69 MJ of energy annually, resulting in total energy-saving costs of CNY 397,007. The dynamic investment payback period is estimated at 9.14 years, and the system reduces CO2 emissions by 753,069.8 kg.

Влияние усовершенствованных технологий создания и использования бобово-злаковых травостоев на урожайность и плодородие дерново-подзолистой почвы луговых сенокосов

To solve the problems posed in the Doctrine to ensure the food security of the population of Russia (2020), it is important to increase the productivity and quality of voluminous fodder on meadow hayfields. In the Federal Scientific Center "VIK named after V.R. Williams", improved technologies have been developed for the creation and use of legume-grass stands (with the participation of four legume species) using presowing inoculation of seeds with complementary strains of nodule bacteria, as well as an agricultural technique — changing the predecessor during overplanting (in order to eliminate the phenomenon of soil fatigue). Articles published in recent years (2008, 2020, 2021, 2023) show the high efficiency of the creation and use of these hayfields. Promising technologies make it possible to obtain 5.8–6.2 thousand feed units/ha with high quality hay with a content of metabolic energy of 9.13–9.65 MJ per 1 kg of dry matter and availability of digestible protein per feed unit — 118–164 g. The payback of capital investments is 1–1.5 years, and the cost of 1 feed unit is 26–30% lower than the prevailing prices for 1 kg of fodder oats. For the first time in the article, materials are presented on the impact of the developed technologies on the change in the fertility of soddy-podzolic soils of the Non-Chernozem zone.

Assessment of the wind energy potential and economic viability of selected sites along Nigeria’s coastal and offshore locations

Wind energy is a promising sector in the power generation industry because it is renewable and globally available. In this research work, the wind energy potential and the economic viability of using wind turbines to generate electricity in some selected sites along Nigeria’s coastline and offshore locations were evaluated. Using the statistical two-parameter Weibull probability density function method, wind speed data retrieved from an indigenous oceanography company and global information system (GIS) were analyzed for wind energy harvest. The energy output, unit cost of electricity generated by three commercially available wind turbine models (3 MW, 4 MW, and 6 MW), net present value (NPV), and payback period were evaluated. Levelized cost of electricity (LCOE) sensitivity to the discount rate, foundation cost, and turbine lifespan were also examined. The findings from the study showed that the offshore sites have four times greater wind power potential than the coastal sites. The offshore sites can be categorized as “class IIIb” wind sites, making the locations suitable for wind energy harvest. The techno-economic analysis showed that the net gains from investing in a 60-MW wind farm in the region can be as high as $62,000,000.00, while the project payback time can be as low as 5.74 years. Two of the offshore sites are recommended for the development of an offshore wind farm in the country because of their relatively low LCOE (0.04 $/kWh), higher NPV, and lower investment payback time. The Vesta-117 model wind turbine is the most suitable wind turbine system and recommended for use in the region because of its low cut-in speed (3 m/s). Sensitivity analysis showed that the LCOE of offshore-01 was reduced by 31% when the lifespan of the V117 turbine was increased from 20 to 25 years. The results also showed that reductions in the discount rate and foundation cost positively affect the LCOE.

Thermo-economic assessments on building heating by a thermal energy storage system with metal foam

Due to the intermittency and discontinuity of solar energy, thermal energy storage (TES) using phase change materials (PCMs) is generally required to ensure stable operation in solar heating systems (SHS) during winter. This paper presents the design of a TES unit with different horizontal metal foam filling ratios (60%–100%), and simulations of thermal characteristics, such as complete melting time and heat storage capacity by numerical method. Based on the heating demands of an office building in Xi'an, TES units are combined in parallel and economic indexes are calculated based on static evaluation method, including initial investment and investment payback period. Novelty, the contribution of gradient microstructure to the phase transition process is evaluated from thermophysical properties and economy. Results show that the TES unit with a filling ratio of 90% possesses the shortest complete melting time of 5310 s, which is 87.56% shorter than that of a TES unit with pure PCM. Finally, economic assessments of the engineering application of the partially filled metal foam structure are carried out, and it is determined that the SHS with the TES system of 90% filling ratio requires the least number of 548 TES units, with a payback period of three heating seasons.

Strategies for heat recovery in a reverse flow reactor designed to lessen coal mine methane emissions test

ABSTRACT Thermal pollution resulting from the release of ventilation air methane (VAM) has emerged as a pressing concern in coal mining. This study aims to address this issue by harnessing the waste VAM energy and converting it into reusable resources, employing an efficient thermal flow reversal reactor. The research investigates five distinct heat extraction strategies and compares their performance. The numerical analysis focuses on transient heat recovery performance by employing a two-step reaction mechanism. Furthermore, the study uncovers the heat transfer characteristics of heat exchange tubes and conducts an analysis of construction costs and profit periods for the different strategies. The findings indicate that the central heat recovery strategy exhibits inferior recovery performance, resulting in higher outlet temperatures and lower extracted power. Conversely, the end recovery strategy successfully reduces heat loss by 56%. The two-sided strategy demonstrates better recovery performance, maintaining an average outlet temperature of 311 K. Additionally, the heat recovery efficiency of the heat exchange tube is approximately 85.6%. Although the combination strategy appears to reduce outlet heat loss, it results in an extended investment payback period.

Performance investigation of a solar/biomass based multi-generation system in pig farm

Intensive pig farm usually needs a large amount of energy, renewable energy supply system contributes to reducing the reliance of fossil fuel. In this study, load prediction of piggery considering different breeding characteristics and climate condition are carried out. An innovative solar/biomass hybrid multi-generation system combined with biomass combustor, ice thermal energy storage, absorption chiller, evacuated flat plate collector, photovoltaic panel and thermal energy storage is proposed. The operation strategy of following cooling demand is designed for proposed system, which considers the feature of high cooling load of piggery. The influences of key parameters on thermodynamic, economy and environment performances are investigated, thermodynamic operation performances of multi-generation system on different typical days are analyzed. Moreover, non-dominated sorted genetic algorithm is used for tri-objective optimization to obtain the optimal operating parameters and performances. Under the optimal condition, exergy and energy efficiency of integrated system are 19.05% and 53.59%, respectively. Compared with separation system, CO2 emission reduction ratio and dynamic investment payback period of multi-generation system are 70.39% and 5.12 years, respectively. In summary, this study offers a novel way for multiple energy coupling poly-generation system in intensive pig farm so as to obtain optimal performance in operation and scheduling.