Design and Simulation of a Digital Twin Mobility Concept: An Electric Aviation System Dynamics Case Study with Capacity Constraints

Vertical mobility, as a commercial service, has been strongly focused on the scheduled volume and long-distance mobility services. Thus, limiting its potential coverage, flexibility, and adaptability with high investments and centralized mobility hubs, called airports. In this context, a customized and on-demand air mobility concept providing high flexibility in location combinations and time schedules appears as an unexplored challenge for regional mobility needs. As a result, the aim of this research is to provide a generic framework for various mobility means as well as to design a holistic air mobility management concept for electric vertical mobility for profitable and sustainable operations by providing a service to society. A system dynamics simulation case study applies the conceptual model for an on-demand air mobility network of electric aircrafts in a regional area considering capacity constraints in vertiports, aircrafts, charging, and parking stations. Thus, bottlenecks and delays can be quantified by using a digital twin tool for customized scenarios. Simulation results show how an optimal maintenance management and redistribution of aircraft units improve service indicators in passenger quantity and customer order lead time as well as reduce aircraft on ground time. As a result, a digital twin air mobility network model with simulation capabilities is a key factor for successful operations.

Next-Generation Genetic and Fermentation Technologies for Safe and Sustainable Production of Food Ingredients: Colors and Flavorings

A growing human population is a significant issue in food security owing to the limited land and resources available for agricultural food production. To solve these problems, sustainable food manufacturing processes and the development of alternative foods and ingredients are needed. Metabolic engineering and synthetic biology can help solve the food security issue and satisfy the demand for alternative food production. Bioproduction of food ingredients by microbial fermentation is a promising method to replace current manufacturing processes, such as extraction from natural materials and chemical synthesis, with more ecofriendly and sustainable operations. This review highlights successful examples of bioproduction for food additives by engineered microorganisms, with an emphasis on colorants and flavors that are extensively used in the food industry. Recent strain engineering developments and fermentation strategies for producing selected food colorants and flavors are introduced with discussions on the current status and future perspectives. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Rethinking Supply Chain Strategy to Face Global Challenges Imposed by COVID-19

COVID-19 has been perceived as a new menace to undertake business relations in the marketplace. Consequently, supply chains have been required to reevaluate how to manage their key functions to cope with harsh business environment under this pandemic outbreak scenario. Therefore, supply chain strategies have taken an essential role in achieving resilience, flexibility, responsiveness and sustainable operations. As a result, the introduction of new digital technologies has contributed to enhance organizational performance and to face COVID-19 challenges in global markets. The purpose of this chapter is to provide insights of current literature on supply chain operations by identifying strategic practices within this pandemic health outbreak crisis. The chapter introduces an overview of the supply chain key functional areas. Then, the discussion concentrates on describing a series of observations and empirical research developed by academics and experts on the topic. After that, supply chain strategic practices are analyzed, followed by a description of digital technology as a critical tool to achieve operational excellence and to compete in tougher market conditions. Finally, a conceptual model is proposed to ensure effective supply chain functioning and value creation across the entire firm’s operations. Conclusion are drawn to summarize the contribution of this chapter and to highlight the importance of rethinking new practices for achieving higher performance results. Future research suggestions are presented to advance the discussion and research in embracing new supply chain models under market uncertainty in terms of demand, supply and operations.

Preliminary Study on New Alternative Binders through Re-Refined Engine Oil Bottoms (REOBs) and Industrial By-Product Additives

Recent studies have worked towards addressing environmental issues such as global warming and greenhouse gas emissions due to the increasing awareness of the depletion of natural resources. The asphalt industry is seeking to implement measures to reduce its carbon footprint and to promote sustainable operations. The reuse of several wastes and by-products is an example of a more eco-friendly activity that fulfils the circular economy principle. Among all possible solutions, the road pavement sector encourages, on one hand, the use of recycled materials as a partial replacement of the virgin lithic skeleton; on the other hand, it promotes the use of recycled materials to substituting for a portion of the petroleum bituminous binder. This study aims to use Re-refined Engine Oil Bottoms (REOBs) as a main substitute and additives from various industrial by-products as a full replacement for virgin bitumen, producing high-performing alternative binders. The REOBs have been improved by utilizing additives in an attempt to improve their specific properties and thus to bridge the gap between REOBs and traditional bituminous binders. An even larger amount of virgin and non-renewable resources can be saved using these new potential alternative binders together with the RAP aggregates. Thus, the reduction in the use of virgin materials is applied at the binder and the asphalt mixture levels. Rheological, spectroscopic, thermogravimetric, and mechanical analysis were used to characterize the properties, composition, and characteristics of the REOBs, REOB-modified binders, and asphalt mixes. Thanks to the rheological investigations of possible alternative binders, 18 blends were selected, since they behaved like an SBS-modified bitumen, and then they were used for producing the corresponding asphalt mixtures. The preliminary mechanical analysis of the asphalt mixtures shows that six mixes have promising responses in terms of stiffness, tensile resistance, and water susceptibility. Nevertheless, the high variability of recycled materials and by-products has to be taken into consideration during the definition of alternative binders and recycled asphalt mixtures. In fact, this study highlights the crucial effects of the chemical composition of the constituents and their compatibility on the behaviour of the final product. This preliminary study represents a first attempt to define alternative binders, which can be used in combination with recycled aggregates for producing more sustainable road materials. However, further analysis is necessary in order to assess the durability and the ageing tendency of the materials.

The role of emerging technologies in implementing green practices to achieve sustainable operations

PurposeThe current study investigates the effect of industry 4.0 on green practices, including green manufacturing and green logistics, in the context of emerging economies.Design/methodology/approachA cross-sectional data were collected from 234 manufacturing firms in Pakistan, and PLS-SEM was employed to test hypotheses.FindingsWith the advent of industry 4.0 in the current era, more emphasis is being given to the adoption of digital technologies in every field. The adoption of the green approach in supply chain management provides firms with socioeconomic and environmental benefits. The study results indicate that industry 4.0 positively affects green practices, including green manufacturing and green logistics. Moreover, the results also illustrate that these green practices have a substantial effect on the sustainability performance of the firms.Research limitations/implicationsThis study provides an amplified understanding of the industry 4.0 technologies in the adoption of green practices. The outcomes also offer a policy framework for managers, legislators and manufacturers to promote green practices (i.e. green manufacturing and green logistics) in businesses.Originality/valueAlthough several recent studies have tried to investigate the effect of green practices on sustainability performance. However, as per the author's best knowledge, very few studies have analyzed the influence of industry 4.0 on green practices (i.e. green manufacturing and green logistics) in the context of emerging economies.

Disruptions in sourcing and distribution practices of supply chains due to COVID-19 pandemic: a sustainability paradigm

Purpose The present research paper is an attempt to study how COVID-19 can affect the global sourcing practices of various supply chain intermediaries across the demand chain. This study aims to explore and is an attempt to understand the overall impact of COVID-19 on the sustainable operations of the firm such as sourcing, procurement, economic performance, social responsibility, consumption and distributions. Design/methodology/approach This study uses a quantitative technique using data collected from 708 respondents. Structural equation modeling (SEM) has been applied to test the proposed model and hypothesis. Findings The findings of the study suggest that sourcing practices, distribution and sustainability considerations of manufacturers, suppliers, distributors and retailers are affected by COVID-19 to a great extent but the pandemic has also led to making supply chain intermediaries understand the changing dynamics of the business scenario which can help them in their own strategic and business evolution. Research limitations/implications The current disruptions throughout global delivery chains caused by COVID-19 affect badly, the already poor-performing supply chains. Hence, the present study provides fresh insight on how organizations can limit the ill effects of COVID-19 by safeguarding some of their key sustainable operations in a post-pandemic business scenario. Originality/value The present study takes into consideration how core supply functions such as sourcing, distribution and manufacturing and various sustainable operations are disrupted by pandemic and its after-effects. This knowledge base can help business organizations to mitigate such problems/disruptions in the future.

To Stay or to Leave? Migrant Workers' Decisions During Urban Village Redevelopment in Hangzhou, China

As a vital source of the demographic dividend, migrant workers living in urban villages have positively contributed to urban economic development and the improvement of urbanization. Although urban villages have had a great impact on public health due to the shabby environments and poor public safety, the large-scale demolition of the urban villages, the supply of affordable housing for migrant workers has decreased drastically, which may lead to the outflow of many migrant workers and consequently affects the sustainable operations of cities. Therefore, this paper takes Hangzhou as an example to study the impact of urban village redevelopment on migrant workers and their migration decisions during urban village redevelopment process. The finding indicates that migrant workers are significantly impacted by large-scale demolition. (1) The number of affected migrant workers is huge. For example, 657,000 migrant workers who lived in around 178 urban villages are affected in Hangzhou (34,468 households). (2) The increase in rent is obvious. (3) Strong expulsion effect: nearly 1/3 migrant workers will decide to leave the city because of the demolition. Furthermore, our binary logistic regression model suggests that the commuting time, living satisfactory, and the rent affordability are factors significantly affecting migration workers' decision to leave and stay in the city. The housing quality and comfort indicators are not significant. This indicates that convenience for employment and high rent avoidance are the major characteristics of migrant workers' housing choice. Hence, in addition to considering whether the harsh environment is harmful to the public health of urban and residents, the interest and characteristics of migrant workers should be considered during the current urban village demolition process. While simply demolishing urban villages, government needs to provide a relatively sufficient amount of low-cost and affordable housing for migrant workers in case migrant workers leave the city in large numbers due to lack of suitable housing in the city.