Photoluminescence Imaging for the In-Line Quality Control of Thin-Film Solar Cells

Renewable energy sources such as photovoltaic (PV) technologies are considered to be key drivers towards climate neutrality. Thin-film PVs, and particularly copper indium gallium selenide (CIGS) technologies, will play a crucial role in the turnaround in energy policy due to their high efficiencies, high product flexibility, light weight, easy installation, lower labour-intensiveness, and lower carbon footprint when compared to silicon solar cells. Nonetheless, challenges regarding the CIGS fabrication process such as moderate reproducibility and process tolerance are still hindering a broad market penetration. Therefore, cost-efficient and easily implementable in-line process control methods are demanded that allow for identification and elimination of non-conformal cells at an early production step. As part of this work, a practical approach towards industrial in-line photoluminescence (PL) imaging as a contact-free quality inspection tool is presented. Performance parameters of 10 CIGS samples with 32 individually contacted cells each were correlated with results from PL imaging using green and red excitation light sources. The data analysis was fully automated using Python-based image processing, object detection, and non-linear regression modelling. Using the red excitation light source, the presented PL imaging and data processing approach allows for a quantitative assessment of the cell performance.

Product Flexibility Strategy Under Supply and Demand Risk

Problem definition: With heightened global uncertainty, supply chain managers are under increasing pressure to craft strategies that accommodate both supply and demand risks. Although product flexibility is a well-understood strategy to accommodate risk, there is no clear guidance on the optimal flexibility configuration of a supply network that comprises both unreliable primary suppliers and reliable backup suppliers. Academic/practical relevance: Existing literature examines the value of flexibility with primary and backup suppliers independently. For a risk-neutral firm, research shows that (a) incorporating flexibility in a primary supplier by replacing two dedicated ones (in absence of backup supply) is always beneficial and that (b) adding flexibility to a reliable backup supplier (in absence of product flexibility in primary suppliers) is always valuable. It is unclear, however, how flexibility should be incorporated into a supply network with both unreliable primary suppliers and reliable backup suppliers. This research studies whether flexibility should be incorporated in a primary supplier, a backup supplier, or both. Methodology: We develop a normative model to analyze when flexibility benefits and when it hurts. Results: Compared with a base case of no flexibility, we prove that incorporating flexibility in either primary or backup suppliers is always beneficial. However, incorporating flexibility in both primary and backup suppliers can be counterproductive because the supply chain performance can decline with saturated flexibility, even if flexibility is costless. A key reason is that the risk-aggregation effect of consolidating flexibility in an unreliable supplier becomes more salient when flexibility is already embedded in a backup supplier. Managerial implications: This research refines the existing understanding of flexibility by illustrating that flexibility is not always beneficial. When there is a choice, a firm should prioritize incorporating flexibility in a reliable backup supplier.

Recommended Methods Supporting Adoption of the Agile Philosophy for Hardware Development

The objective of this research is to understand the historical evolution of software development, identify desirable characteristics of methods supporting agile for hardware, and recommend potential methods enabling agile development of hardware products. As technology and markets change, product development increasingly operates in a volatile, uncertain, complex, and ambiguous (VUCA) environment. While originally applied to software development, organizations are starting to see opportunity in adapting the agile philosophy for hardware development. A comparison of philosophies is made between waterfall, spiral, and agile development. The historical evolutions of software development, after agile, including Continuous Integration Continuous Deployment (CICD), Development and Operations (DevOps), and Development Security and Operations (DevSecOps) is presented. Benefits and challenges in the application of agile methods for hardware are presented. Benefits include improvements in flexibility in response to change and soft factors such as team communication, transparency and commitment. However, many challenges still remain. These are grouped into theme areas including lack of product flexibility, difficulty in separating deliverables, challenges with breaking down tasks within a sprint, changes needed in culture and mindset, difficulty scaling beyond pilot programs, team distribution, and development of an integrated approach across the product lifecycle. Potential methods to aid in the adoption of agile for hardware are discussed using the phases of the hardware development lifecycle as a framework. Recommended methods include the adaptation of Model Based Systems Engineering (MBSE) for problem definition, the use of generative methods for design, the application of Virtual Reality (VR) for prototyping, leveraging additive manufacturing for production, and favoring software defined systems to help in operations. By reducing both the duration and person-hours, these methods enable higher iteration rates for hardware products needed for an agile philosophy. The paper concludes with a discussion on future research efforts supporting the enabling agile development of hardware.

Supply chain flexibility fit and green practices: evidence from the event industry

Purpose As the event industry is supported by a wide range of suppliers that provide different products and services, all these partners in the supply chain can play a crucial role in green practices. The industry needs to have a sufficient degree of supply chain flexibility to cater to the demands in today’s dynamic environment and the flexibility in the supply chain will help event businesses to be sustainable. This study aims to explore the role of the supply chain flexibility fit between event planner’s requirements and supplier offerings on the implementation of green practices. The study also attempted to provide insights into the adoption of green event practices by identifying the moderating roles of green organization image and public pressure. Design/methodology/approach Data analysis was conducted based on 207 useable responses from event planners. Polynomial regression and response surface analysis were performed to verify the hypothesized relationships. Additionally, hierarchical regression analysis was used to test the moderating effects of green organization image and public pressure on the proposed relationships. Findings Results revealed that product flexibility fit was positively related to green practices; however, such effect was not found in the volume flexibility fit model. Findings also showed that public pressure significantly improved the positive effect of product flexibility fit on green practices. However, the green organization image was found to have no significant moderating effect. Practical implications The adoption of green practices requires well-designed collaboration among supply chain partners. This study offers empirical evidence regarding the importance of achieving product flexibility fit between event planners’ requirements and supplier offerings when conducting green practices. The findings provide useful implications that can be applied for successful green event management. Originality/value Despite the significance and relevance of the topic, barely any study has been conducted to assess supply chain flexibility and its relationship with green event practices. The study adopted resource orchestration theory to examine the role of supply chain flexibility on green event practices by focusing on the planner-supplier flexibility fit. A number of implications regarding supply chain management and future research are identified.

Stepping on the Gas to a Circular Economy: Accelerating Development of Carbon-Negative Chemical Production from Gas Fermentation

Owing to rising levels of greenhouse gases in our atmosphere and oceans, climate change poses significant environmental, economic, and social challenges globally. Technologies that enable carbon capture and conversion of greenhouse gases into useful products will help mitigate climate change by enabling a new circular carbon economy. Gas fermentation using carbon-fixing microorganisms offers an economically viable and scalable solution with unique feedstock and product flexibility that has been commercialized recently. We review the state of the art of gas fermentation and discuss opportunities to accelerate future development and rollout. We discuss the current commercial process for conversion of waste gases to ethanol, including the underlying biology, challenges in process scale-up, and progress on genetic tool development and metabolic engineering to expand the product spectrum. We emphasize key enabling technologies to accelerate strain development for acetogens and other nonmodel organisms. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 12 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A New Decision-Making Approach Based on Fermatean Fuzzy Sets and WASPAS for Green Construction Supplier Evaluation

The construction industry is an important industry because of its effects on different aspects of human life experiences and circumstances. Environmental concerns have been considered in designing and planning processes of construction supply chains in the recent past. One of the most crucial problems in managing supply chains is the process of evaluation and selection of green suppliers. This process can be categorized as a multi-criteria decision-making (MCDM) problem. The aim of this study is to propose a novel and efficient methodology for evaluation of green construction suppliers with uncertain information. The framework of the proposed methodology is based on weighted aggregated sum product assessment (WASPAS) and the simple multi-attribute rating technique (SMART), and Fermatean fuzzy sets (FFSs) are used to deal with uncertainty of information. The methodology was applied to a green supplier evaluation and selection in the construction industry. Fifteen suppliers were chosen to be evaluated with respect to seven criteria including “estimated cost”, “delivery efficiency”, “product flexibility”, “reputation and management level”, “eco-design”, and “green image pollution”. Sensitivity and comparative analyses were also conducted to assess the efficiency and validity of the proposed methodology. The analyses showed that the results of the proposed methodology were stable and also congruent with those of some existing methods.

DERIVATION OF STARTING SOLUTIONS BASED ON PRODUCT ARCHITECTURE FLEXIBILITY EVALUATION

Manufacturing companies nowadays face growing numbers of heterogeneous customer requirements. Due to that, internal and external complexity lead to an increase in the associated costs. Especially companies with a high Engineer-to-Order business are strongly affected. To reduce external and internal complexity, Starting Solutions are a suitable way to do that. Starting Solutions require on the one hand the evaluation of product flexibility, on the other hand the evaluation of customer requirements. These two requirements are compared to each other and Starting Solutions are thereby derived.

Using conjoint analysis to understand customer preferences in customized low-income housebuilding projects

Mass customization is a strategy to improve value generation for customers, by offering product variety and, at the same time, maintaining costs and delivery time to an acceptable level. A key problem for applying this strategy in the housebuilding sector is the definition of the solution space, i.e. the range of product alternatives that will be offered. This paper proposes an adaptation of conjoint analysis to identify customer preferences regarding customizable attributes in low-cost housing projects. The utility of this adaptation is illustrated by a case study, which was carried out in a construction company that had delivered low-income housing projects, and offered some degree of product flexibility. Results indicate that this technique was effective to understand customers' preferences out of a range of housing attributes, by providing a ranking of those attributes chosen by customers. Therefore, this technique can support decision-making when dealing with trade-offs between customers' preferences, product flexibility and costs, which is an important concern for companies that deliver customized housing units.