When remanufacturing meets product quality improvement: the impact of production cost

Remanufacturing as well as quality improvement are important activities to improve sustainability. However, when coexisting in one company, their interaction is not clear. On the one hand, past research found a positive impact of remanufacturing on product quality. On the other hand, remanufacturing was shown to be negatively affected by an industry technology trajectory of quality improvements. Using a stylized model of endogenous product quality improvement and remanufacturing we find that the main driver of the contradicting results is the change in manufacturing costs caused by improving product quality. A strong increase in manufacturing costs due to product quality improvement may induce the firm to take up remanufacturing when introducing the new product. Conversely, a small impact of product quality improvement on manufacturing costs reverses this effect and may indeed lead the firm to cease remanufacturing when introducing the new product. We find that the latter outcome is never beneficial from an environmental point of view, while the former always is. With endogeneous product quality improvement we then characterize conditions where a remanufacturing manufacturer would take a different product quality improvement decision than a non-remanufacturing manufacturer. We observe that remanufacturing stifles (stimulates) product quality improvement when manufacturing cost of quality improved product are low (high). Neither of the two results are exclusively beneficial or detrimental from an environmental perspective and we characterize the conditions under which product quality improvement is preferable

To innovate or not to innovate

In this paper we analyze the evolution of output decisions of adaptive firms in an environment of oligopolistic competition. The firm might either choose to produce one of several existing product variants or try to establish a new product variant on the market. The demand for each individual product variant is subject to a life-cycle, but aggregate demand for product variants is constant over time. Every period each firm has to decide whether to produce the product again, to introduce a new product variant itself (which generates an initial advantage on that market), or to follow another firm and change to the production of an already established product. Different firms have heterogeneous abilities to develop products respectively imitate existing designs, and therefore the effects of the decision whether to imitate existing designs or to innovate differ between firms. We examine the evolution of behavior in this market using an agent based simulation model. The firms are endowed with simple rules to estimate market potentials and market founding potentials of all firms including themselves, and make their decisions using a stochastic learning rule. Furthermore, the characteristics of the firms change dynamically due to 'learning by doing' effects. The main questions discussed are how the success and the optimal strategy of a firm depend on the interplay between characteristics of the industry and properties of the firm.Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science

On the Robustness of the Consumer Homogeneity Assumption with Respect to the Discount Factor for Remanufactured Products

The strategic closed-loop supply chains (CLSCs) literature makes the assumption that a consumer’s willingness-to-pay (WTP) for a remanufactured product is a fraction of his/her WTP for the corresponding new product, and this fraction, called discount factor, is assumed to be constant among consumers. Recent empirical research challenges this assumption, by showing that there is considerable variability in discount factors among consumers. This paper considers a complex model in the CLSC literature: strategic remanufacturing under quality choice, and compares its solution under constant discount factors with the solution that assumes a probability distribution for the discount factors (which is analytically intractable and must be obtained numerically). We consider quality choice and remanufacturing for both monopoly and competitive cases. Overall, we find remarkable consistency between the results of the constant and variable discount factor models. Thus, we make a convincing argument that the constant discount factor assumption is robust and can be used due to its tractability

Chiral particle separation by a non-chiral micro-lattice

We conceived a model experiment for a continuous separation strategy of chiral molecules (enantiomers) without the need of any chiral selector structure or derivatization agents: Micro-particles that only differ by their chirality are shown to migrate along different directions when driven by a steady fluid flow through a square lattice of cylindrical posts. In accordance with our numerical predictions, the transport directions of the enantiomers depend very sensitively on the orientation of the lattice relatively to the fluid flow

A Variable Neighborhood Search for the Multi Depot Vehicle Routing Problem with Time Windows

The aim of this paper is to propose an algorithm based on the philosophy of the Variable Neighborhood Search (VNS) to solve Multi Depot Vehicle Routing Problems with Time Windows. The paper has two main contributions. First, from a technical point of view, it presents the first application of a VNS for this problem and several design issues of VNS algorithms are discussed. Second, from a problem oriented point of view the computational results show that the approach is competitive with an existing Tabu Search algorithm with respect to both solution quality and computation time

The perspective of customers and repair companies

Publisher Copyright: © 2023 The Author(s)Using repair services instead of new purchases creates local added value and contributes to a circular economy. The main aim of this research was to characterize repair service convenience for customers and to investigate ways to increase convenience to make repairs more attractive for customers, as the construct service convenience has neither been used nor adapted to a repair context until now. For this purpose, focus group interviews with potential customers of repair companies and interactive workshops with repair companies were conducted in the region of Styria (Austria). Findings state that a variety of factors like lack of information regarding repair services and product repairability, inconvenient store hours, or long waits reduce repair service convenience. However, due to skilled labor shortage, long delivery times of spare parts, or lacking financial resources for advertisements, repair companies can only partially improve convenience. Considering that, interventions from different actors, for example, the local government are needed as they can increase convenience by organizing awareness/information events, repair networks, or central repair-points. Hence, this study highlights once more the necessity to collaborate with different stakeholders (including customers, repair companies, local initiatives, and governments) to successfully transform the linear economy to a circular economy.publishersversionpublishe

Enabling Cysteine-Free Native Chemical Ligation at Challenging Junctions with a Ligation Auxiliary Capable of Base Catalysis

Ligation auxiliaries are used in chemical protein synthesis to extend the scope of native chemical ligation (NCL) beyond cysteine. However, auxiliary-mediated ligations at sterically demanding junctions have been difficult. Often the thioester intermediate formed in the thiol exchange step of NCL accumulates because the subsequent S→N acyl transfer is extremely slow. Here we introduce the 2-mercapto-2-(pyridin-2-yl)ethyl (MPyE) group as the first auxiliary designed to aid the ligation reaction by catalysis. Notably, the MPyE auxiliary provides useful rates even for junctions containing proline or a β-branched amino acid. Quantum chemical calculations suggest that the pyridine nitrogen acts as an intramolecular base in a rate-determining proton transfer step. The auxiliary is prepared in two steps and conveniently introduced by reductive alkylation. Auxiliary cleavage is induced upon treatment with TCEP/morpholine in presence of a MnII complex as radical starter. The synthesis of a de novo designed 99mer peptide and an 80 aa long MUC1 peptide demonstrates the usefulness of the MPyE auxiliary.Peer Reviewe