•Production scale expansion analysis of two-stage network system is investigated.•A simple sufficient and necessary condition is provided for congestion identification.•The limited input increment ...capacity of the DMUs is considered.•The approach is applicable in the presence of multiple outputs.•A case study of China’s agriculture industry is proceeded.
In managerial practice, decision-makers usually confront the problem of whether an organization (or decision-making unit, DMU) could expand its production to increase output. This paper develops new approaches for production scale expansion analysis and target setting of two-stage network systems based on data envelopment analysis. First, the technique of fixing the strongly efficient frontier is adopted to ensure that the analysis proceeds on the efficient frontier. Second, a model is proposed to obtain the maximum aggregated output for each DMU. A two-step procedure is then developed for production scale expansion analysis to check if expanding a DMU’s production scale (i.e., increasing the inputs and intermediate measures) would increase, maintain, or decrease its outputs (due to congestion). Further, we build a model to set appropriate production scale expansion targets for DMUs capable of increasing outputs through production scale expansion, considering their limited ability to increase inputs. Our approach always proceeds with production scale expansion analysis on the production efficient frontier. It also provides a simple sufficient and necessary condition to judge the congestion situation of a DMU in production scale expansion. Finally, we illustrate the proposed approach using a simple numerical example and a case study of China’s agricultural industry.
Green agricultural technology has the potential to not only alleviate the degradation of soil fertility, but also to improve the agricultural productivity of smallholders. In this paper, taking straw ...incorporation as an example, experiments were conducted in Chinese villages to directly measure the time preferences of farmers, and an attempt was made to evaluate the contribution of time preferences to farmers' technology adoption behavior. Furthermore, this research aims to assess the moderating role of production scale between the farmer's time preferences and technology adoption. This study is a continuation of previous studies on factors influencing green agricultural technology adoption. The results show that time preferences significantly reduce technology adoption; in particular, farmers who are more present-biased have a lower proportion of technology adoption. This is because farmers with lower discount rates are more sensitive to future income. Further analysis indicates that compared with small-scale farmers, large-scale farmers are more likely to adopt green technology. It is posited that this occurs because large-scale farmers will gain more benefits by adopting green agricultural technology, and thus, they will be more sensitive to high profits in the future. Moreover, the increase of production scale can reduce the inhibitory effect of time preferences on farmers' technology adoption, which means that scale economies play a moderating role between the farmer's time preferences and their technology adoption. Overall, this research provides a micro foundation and policy recommendations for green agricultural technology promotion and sheds light upon how the government can formulate relevant policies to promote green agricultural development.
•We conducted a field experiment to elicit the time preferences of Chinese rice farmers.•Farmers with higher time preferences are less likely to adopt green agricultural technology.•Large-scale farmers are more likely to adopt green agricultural technology than small-scale farmers.•The increase of production scale can reduce the inhibitory effect of time preferences on farmers' technology adoption.
House flies, Musca domestica, L., (Diptera: Muscidae) are well-known pests at animal facilities; however, they can be used for manure biodegradation. Utilizing house flies to process animal manure ...offers a means to recycle nutrients and reduce contaminants (e.g., pathogens and heavy metals), while also producing multiple revenue streams (e.g., protein for feed, fat for biodiesel, frass as a soil amendment). This study determined house fly larval performance on a larger scale (kilogram of wastes; thousands of larvae; single feeding) as a follow-up to a previous experiment performed at a bench-top scale (g of wastes; hundreds of larvae; incremental feeding). Four thousand larvae were fed 1 kg of swine, dairy, or poultry manure, or a control (Gainesville diet: 50% wheat bran, 30% alfalfa meal, and 20% corn meal). Peak larval weight occurred 4 days after inoculation and no significant difference in development time to first pupariation occurred across diets. However, percent survivorship to pupariation varied, with the highest occurring in Gainesville (74%), swine (73%), and poultry (67%) manure, whereas 50% survived when fed dairy manure. The highest pupal weight was found for those fed Gainesville (27 mg), and similar weights were found for those fed swine (21 mg), dairy (24 mg), and poultry (25 mg) manure. Although using house flies to manage manure has received little consideration in Western countries, other regions have this practice in place. Results may provide insight on differences between small- and large-scale studies, which is valuable for industrialization of this species for waste management and creating a more circular economy.
Currently, researchers have focused on electrokinetic (EK) bioremediation due to its potential to remove a wide-range of pollutants. Further, to improve their performance, synthetic surfactants are ...employed as effective additives because of their excellent solubility and mobility. Synthetic surfactants have an excessive position in industries since they are well-established, cheap, and easily available. Nevertheless, these surfactants have adverse environmental effects and could be detrimental to aquatic and terrestrial life. Owing to social and environmental awareness, there is a rising demand for bio-based surfactants in the global market, from environmental sustainability to public health, because of their excellent surface and interfacial activity, higher and stable emulsifying property, biodegradability, non- or low toxicity, better selectivity and specificity at extreme environmental conditions. Unfortunately, challenges to biosurfactants, like expensive raw materials, low yields, and purification processes, hinder their applicability to large-scale. To date, extensive research has already been conducted for production scale-up using multidisciplinary approaches. However, it is still essential to research and develop high-yielding bacteria for bioproduction through traditional and biotechnological advances to reduce production costs. Herein, this review evaluates the recent progress made on microbial-surfactants for bioproduction scale-up and provides detailed information on traditional and advanced genetic engineering approaches for cost-effective bioproduction. Furthermore, this study emphasized the role of electrokinetic (EK) bioremediation and discussed the application of BioS-mediated EK for various pollutants remediation.
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•Recent biotechnological advances for production scale-up have been discussed.•Currently available tools from traditional to advanced genetic engineering have been summarized.•Straw biomass valorization as a renewable low-cost feedstock's has been described.•BioS are promising alternative to synthetic surfactants for EK remediation additives.•BioS-assisted EK remediation of various environmental pollutants has been reviewed.
This study investigates the material and mechanical properties of both polyamide 12 (PA12) and reinforced glass bead PA12 composites, fabricated using a production scale additive manufacturing (AM) ...process. The printing studies were carried out using the production scale, Multi Jet Fusion powder bed fusion process. The study demonstrated that the chemical functionality and the thermal properties of the printed PA 12 parts and the glass bead composite, were similar. Almost identical infrared spectra were obtained demonstrating the same chemical functionality. Based on DSC measurements, the melting temperature was 184 °C and 186 °C and the associated cooling cycle temperature was 150 °C and 146 °C for the composite and the PA12 respectively. The percentage crystallinity of the glass bead composite was 24 %, compared with the 31 % obtained for the PA12 only parts. Based on mechanical tests, the addition of glass beads increased the tensile and flexural modulus by 85 % and 36 % and lowered the tensile and flexural strength by 39 % and 15 % respectively. The effect of print orientation during the MJF process was evaluated based on porosity and mechanical performance. Using X-ray micro computed tomography, it was demonstrated that the porosity of the PA12 and composite parts were less than 1 %. Polymer and composite parts printed in the ZYX orientation were found to exhibit both the lowest porosity and highest mechanical strengths.
Crop insurance is critical in risk management in global agricultural production (e.g. by helping stabilise farmers' incomes in the long term and reducing risk-bearing costs). In this paper, using ...field survey data on cotton farmers in Xinjiang, China, we examine the influence of crop insurance on farmers' behaviours regarding agrochemical inputs and aim to investigate the synergy between crop insurance and reductions in fertiliser and pesticide usage. We find evidence that crop insurance significantly negatively affects farmers' use of fertilisers and pesticides, as well as significantly positively affects their adoption of green agricultural technologies (GAT) that can replace or complement traditional fertilisers and pesticides. Moreover, our results reveal that compared with small-scale farmers, crop insurance has a stronger effect on large-scale farmers' use of agrochemicals. Finally, when the insured amount is higher or the relative deductible is lower, farmers are more likely to reduce fertiliser and pesticide usage and adopt GAT. Overall, this paper scientifically identifies crop insurance can improve farmers' agrochemical input behaviour, by reducing farmers' use of traditional agrochemical inputs and increasing their adoption of GAT, which is of great significance for ensuring the safety of the agricultural ecological environment.
•A new two-stage network data envelopment analysis approach is proposed.•It matches substages’ production scale with intermediate measure levels.•It uses a total value flow equivalence between a ...unit's two stages.•Primal-dual correspondence holds.•It avoids uncertainties in determining divisional efficiencies.
We develop a new network data envelopment analysis (DEA) approach for two-stage network systems considering a match between the production scale of the substages and the intermediate measure levels. Several explicit production axioms are introduced to build a production possibility set. New models are developed based on the production possibility set and a frontier projection procedure with the production scale matching process. Unlike the existing approach which assumes the intermediate measures are free-setting decision variables, the new envelopment network DEA models project the intermediate measures of a unit using the radial projection technique. Correspondingly, the resulting multiplier network DEA models allow for weight flexibility on the intermediate measures while holding a total value flow equivalence between a unit's two stages. We show that our approach does not suffer the known network DEA pitfalls. It identifies the overall efficiency, divisional efficiencies, and frontier projection using either an envelopment or a multiplier network DEA model, i.e., the primal-dual correspondence holds in our approach. Our approach also avoids uncertainties in determining divisional efficiencies by generating a unique pair of divisional efficiencies for each unit. Additionally, the adoption of the production scale matching process explains clearly the frontier projection procedure from the practical point of view. The proposed approach is illustrated with a numerical example and compared with the existing approaches with a case study of commercial bank branches.
Additive manufacturing (AM) is rapidly becoming one of the most popular manufacturing techniques for short run part production and rapid prototyping. AM encompasses a range of technologies, including ...powder bed fusion (PBF) process. The purpose of this paper is to evaluate and benchmark the mechanical performance of polyamide 12 (PA12) parts, fabricated using a production scale powder bed fusion printing process (HP Multi Jet Fusion printing process). This system has a build volume is 380 × 254 × 350 mm. The printed polymer parts were examined to determine their hydrophobicity, morphology, porosity and roughness. Chemical and thermal properties of the PA12 parts were also evaluated using attenuated total reflection infrared spectroscopy (ATR FT-IR), x-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC). The study highlights the influence of build orientation on the tensile (ISO 527-1:2012) and flexural (ISO 178:2010) properties. In terms of tensile strength, the parts exhibited isotropic behaviour with a maximum tensile strength of 49 MPa. In terms of flexural testing, the build orientations had a significant effect on the strength of the printed part. The Z orientation exhibited a 40% higher flexural strength, when compared to that of the X orientation. The maximum flexural strength observed was 70 MPa. The results of this rapid, production scale AM study are compared with previous studies that detail the mechanical performance of PA12, fabricated using PBF processes, such as selective laser sintering.
•The strongly context-dependent decision-making unit is investigated.•New returns to scale analysis approach considering contextual factors is suggested.•A new model is proposed to estimate the ...optimal production scale.•The estimated optimal production scale is DEA-efficient and operates at the most productive returns to scale.•A case study of 31 main airports in China in 2022 is provided.
In practical management scenarios, decision-makers frequently face the challenge of determining the most effective production scale for a strongly context-dependent decision-making unit (SCD-DMU). A notable hallmark of the SCD-DMU is its substantial reliance on contextual factors when establishing its production scale. This research proposes an approach based on data envelopment analysis (DEA) to estimate the optimal production scale of SCD-DMUs. Firstly, we expand the traditional explicit axioms in DEA to encompass contextual factors, followed by introducing a new DEA model designed to assess the efficiency of SCD-DMUs. Secondly, several models are presented to analyze whether a specific SCD-DMU exhibits increasing, decreasing, or constant returns to scale (RTS). Furthermore, an optimal production scale estimation model is introduced to calculate the optimal production scales for SCD-DMUs while considering their contextual factors. Our approach contributes by introducing a specialized efficiency evaluation model for SCD-DMUs, incorporating techniques for identifying their RTS and estimating the optimal production scale. It should be highlighted that the proposed production scale estimation model can simultaneously estimate the optimal input and output, and the estimated SCD-DMUs are DEA-efficient and operate at the most productive returns to scale. Finally, we apply the proposed approach to a real case study of 31 main airports in China in 2022 and compare it with two representative models.
Abstract
Context
Bioenergy from wood can contribute to reach the goals of energy-transition policies. Use of wood as fuel should focus on low-quality wood, e.g. by-products from timber production, ...which production and supply is related to various management decisions. Reaching the policy objectives efficiently remains an issue.
Aims
The aims are (1) to develop a modelling approach that links local management decisions with indicators of the whole wood fuel production and supply chain and (2) to test the model in a case study. The study should further provide first insights on how indicators of energy, nutrient and worktime efficiency vary according to wood fuel chain characteristics and the related management decisions.
Methods
The model depicts the flow of wood (biomass, nutrients, moisture content, heating value) from the forest stand to the heating plant for each silvicultural intervention simulated with a growth and yield model. It further quantifies the energy and worktime spent on different wood fuel chain tasks (e.g. felling, forwarding) set by the user. We defined four scenarios according to the scale of energy production (large vs. small) and the demand for wood fuel (high vs. moderate).
Results
The case study revealed that the model outputs were plausible. Energy efficiency largely varied depending on the type of silvicultural intervention. Large-scale production associated with high demand was most favourable for energy and worktime efficiencies. In contrast, nutrient efficiency was best for small-scale production associated with moderate demand.
Conclusions
Local management decisions all along the wood fuel chain highly influenced efficiency indicators, and thus its relevance for energy-transition policies. Our model may contribute to strategic decision making in different forestry and energy production contexts.
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