{"title":"The bullwhip effect, market competition and standard deviation ratio in two parallel supply chains","authors":"Xuluo Yin, Wenting Tang","doi":"10.1016/j.compchemeng.2024.108916","DOIUrl":"10.1016/j.compchemeng.2024.108916","url":null,"abstract":"<div><div>The bullwhip effect widely exists in supply chains and shows its significance for the competitiveness of enterprises in supply chains. In this study, we analyze the bullwhip effect in two parallel supply chains with competing products, each one consisting of a supplier and a retailer. A model is detailed for measuring the bullwhip effect in which the demand of retailers follows a similar vector autoregressive model (VAR-like) process. The results show that the bullwhip effect can be characterized as a quadratic function of the standard deviation ratio. The impact of market competition on the bullwhip effect of the supply chain may have the opposite result, which depends on some parameters, including lead time and market competition in the parallel supply chain. The parameters have asymmetric influence on bullwhip effect. Compared with VAR(1) and AR(1) model, the empirical results show that our VAR(1)-like model is closer to reality. Furthermore, we discuss the conclusion of research and its inspiration for supply chain management.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108916"},"PeriodicalIF":3.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jesper Frandsen , Jan Michael Breuer , Johannes Schmölder , Jakob Kjøbsted Huusom , Krist V. Gernaey , Jens Abildskov , Eric von Lieres
{"title":"CADET-Julia: Efficient and versatile, open-source simulator for batch chromatography in Julia","authors":"Jesper Frandsen , Jan Michael Breuer , Johannes Schmölder , Jakob Kjøbsted Huusom , Krist V. Gernaey , Jens Abildskov , Eric von Lieres","doi":"10.1016/j.compchemeng.2024.108913","DOIUrl":"10.1016/j.compchemeng.2024.108913","url":null,"abstract":"<div><div>This study introduces CADET-Julia, an open-source, versatile and fast chromatography solver implemented in the Julia programming language. The software offers a platform for rapid prototyping and numerical refinement for a range of chromatography models, including the general rate model (GRM). The interstitial column mass balance was spatially discretized using a strong-form discontinuous Galerkin spectral element method (DGSEM) whereas a generalized spatial Galerkin spectral method (GSM) was applied for the particle mass balance. Three different benchmarks showcased the computational efficiency of CADET-Julia: A baseline benchmark was established by comparing the Julia implementation to a C++ implementation that employed the same mathematical methods and time integrator (CADET-DG). Various Julia time integrators were tested, and with the best-performing settings, the Julia implementation was benchmarked against CADET-DG and a finite volume (FV) based implementation in C++ (CADET-FV). Overall, Julia implementations performed better than C++ implementations and Galerkin methods were generally superior to finite volumes.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108913"},"PeriodicalIF":3.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hazem Damiri , Martin Steinberger , Lisa Kuchler , Atabak Azimi , Stefano Martinuzzi , Peter Sagmeister , Jason D. Williams , Stefan Koch , Markus Tranninger , Jakob Rehrl , Selma Celikovic , Stephan Sacher , C. Oliver Kappe , Martin Horn
{"title":"Model-based real-time optimization in continuous pharmaceutical manufacturing","authors":"Hazem Damiri , Martin Steinberger , Lisa Kuchler , Atabak Azimi , Stefano Martinuzzi , Peter Sagmeister , Jason D. Williams , Stefan Koch , Markus Tranninger , Jakob Rehrl , Selma Celikovic , Stephan Sacher , C. Oliver Kappe , Martin Horn","doi":"10.1016/j.compchemeng.2024.108915","DOIUrl":"10.1016/j.compchemeng.2024.108915","url":null,"abstract":"<div><div>In this work, real-time optimization (RTO) schemes are proposed and applied on a continuous pharmaceutical manufacturing process which consists of three units: synthesis unit, hot melt extrusion unit and direct compaction line. The developed RTO strategies calculate the operating conditions by optimizing the considered objective functions while satisfying the specific constraints. Moreover, the RTO schemes can cope with intentional changes in the process and unintentional changes such as disturbances. Results from simulations and experiments are presented in this work. An advantageous performance is achieved when using the developed schemes.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108915"},"PeriodicalIF":3.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yan Qi , Lifeng Zhao , Haiqiu Tang , Lei Zhang , Rafiqul Gani
{"title":"Computer aided formulation design based on molecular dynamics simulation: Detergents with fragrance","authors":"Yan Qi , Lifeng Zhao , Haiqiu Tang , Lei Zhang , Rafiqul Gani","doi":"10.1016/j.compchemeng.2024.108919","DOIUrl":"10.1016/j.compchemeng.2024.108919","url":null,"abstract":"<div><div>Computer-aided formulation design is a methodology that utilizes domain knowledge and selected methods and tools suitable for computer-based applications to assist in formulation (product) design. In this paper, molecular dynamics simulation and Bayesian neural network algorithms are combined with well-known engineering models to help accelerate the development and optimization of formulation-based detergent products with a view to improve product quality and performance. In particular, the mechanism of the behavior of polymers (an active ingredient in the product) to improve the product quality in terms of the fragrance and its residence time is highlighted. Results from molecular dynamic simulation applied to study the molecular interaction mechanism show that the polymers have an attraction effect with fragrance molecules and could adsorb more to make them to stay on the surface of clothes. In addition, the polymer attenuates the diffusion of the fragrance molecules, lengthening the entire process of fragrance diffusion, which is the essence of the ability of the polymer to slow down the release of the fragrance. A Quantitative Structure-Property Relationship (QSPR) model between component proportions and fragrance diffusion is established through Bayesian Neural Network (BNN) and the product formulation is optimized based on this model. Keeping polymer and perfume ingredients unchanged, the surfactant amounts are optimized to provide improved product quality.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108919"},"PeriodicalIF":3.9,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Risk-averse supply chain management via robust reinforcement learning","authors":"Jing Wang , Christopher L.E. Swartz , Kai Huang","doi":"10.1016/j.compchemeng.2024.108912","DOIUrl":"10.1016/j.compchemeng.2024.108912","url":null,"abstract":"<div><div>Classical reinforcement learning (RL) may suffer performance degradation when the environment deviates from training conditions, limiting its application in risk-averse supply chain management. This work explores using robust RL in supply chain operations to hedge against environment inconsistencies and changes. Two robust RL algorithms, <span><math><mover><mrow><mi>Q</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span>-learning and <span><math><mi>β</mi></math></span>-pessimistic <span><math><mi>Q</mi></math></span>-learning, are examined against conventional <span><math><mi>Q</mi></math></span>-learning and a baseline order-up-to inventory policy. Furthermore, this work extends RL applications from forward to closed-loop supply chains. Two case studies are conducted using a supply chain simulator developed with agent-based modeling. The results show that <span><math><mi>Q</mi></math></span>-learning can outperform the baseline policy under normal conditions, but notably degrades under environment deviations. By comparison, the robust RL models tend to make more conservative inventory decisions to avoid large shortage penalties. Specifically, fine-tuned <span><math><mi>β</mi></math></span>-pessimistic <span><math><mi>Q</mi></math></span>-learning can achieve good performance under normal conditions and maintain robustness against moderate environment inconsistencies, making it suitable for risk-averse decision-making.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108912"},"PeriodicalIF":3.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Jaynes machine: The universal microstructure of deep neural networks","authors":"Venkat Venkatasubramanian , N. Sanjeevrajan , Manasi Khandekar , Abhishek Sivaram , Collin Szczepanski","doi":"10.1016/j.compchemeng.2024.108908","DOIUrl":"10.1016/j.compchemeng.2024.108908","url":null,"abstract":"<div><div>Despite the recent stunning progress in large-scale deep neural network applications, our understanding of their microstructure, ‘energy’ functions, and optimal design remains incomplete. Here, we present a new game-theoretic framework, called statistical teleodynamics, that reveals important insights into these key properties. The optimally robust design of such networks inherently involves computational benefit–cost trade-offs that physics-inspired models do not adequately capture. These trade-offs occur as neurons and connections compete to increase their effective utilities under resource constraints during training. In a fully trained network, this results in a state of arbitrage equilibrium, where all neurons in a given layer have the same effective utility, and all connections to a given layer have the same effective utility. The equilibrium is characterized by the emergence of two lognormal distributions of connection weights and neuronal output as the universal microstructure of large deep neural networks. We call such a network the Jaynes Machine. Our theoretical predictions are shown to be supported by empirical data from seven large-scale deep neural networks. We also show that the Hopfield network and the Boltzmann Machine are the same special case of the Jaynes Machine.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108908"},"PeriodicalIF":3.9,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu Zhang , Junyao Xie , Qingqing Xu , Charles Robert Koch , Stevan Dubljevic
{"title":"Physics-informed neural networks for state reconstruction of hydrogen energy transportation systems","authors":"Lu Zhang , Junyao Xie , Qingqing Xu , Charles Robert Koch , Stevan Dubljevic","doi":"10.1016/j.compchemeng.2024.108898","DOIUrl":"10.1016/j.compchemeng.2024.108898","url":null,"abstract":"<div><div>Hydrogen energy, as one of the promising future energy forms, has attracted attentions from academia and industry due to its cost-effective and low-carbon nature. Compared with oil and gas transportation, its transportation is more challenging due to its complex blending mechanism. Inferring the internal states during transportation is essential for condition monitoring and operational planning of hydrogen-blending natural gas pipelines. Considering the nonlinear spatiotemporal dynamics and limited sensor information, reconstructing infinite-dimensional pipeline state variables is challenging. This paper addresses the state reconstruction of nonlinear infinite-dimensional hydrogen-blending natural gas pipeline systems using physics-informed neural networks. The proposed design combines neural networks with nonlinear partial differential equations that govern the pipeline systems. With limited measurements, the trained model is capable of predicting the state evolutions of pressure, flow, and mass flux ratio of hydrogen during transient transportation at any location. The proposed design is demonstrated through detailed numerical simulations and sensitivity analyses.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108898"},"PeriodicalIF":3.9,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mouad Sidki , Nikolay Tchernev , Pierre Féniès , Libo Ren , Selwa Elfirdoussi
{"title":"Multiproduct pipeline scheduling: A comprehensive bibliometric analysis and a systematic literature review","authors":"Mouad Sidki , Nikolay Tchernev , Pierre Féniès , Libo Ren , Selwa Elfirdoussi","doi":"10.1016/j.compchemeng.2024.108911","DOIUrl":"10.1016/j.compchemeng.2024.108911","url":null,"abstract":"<div><div>Multiproduct pipeline scheduling problem has garnered increasing attention over the past few decades due to potential economic savings and increased operational efficiency. This paper presents a comprehensive bibliometric analysis and systematic literature review on multiproduct pipeline scheduling, focusing on works published from 2000 to 2023. Using three reputable bibliographic databases, the research gathers and examines metadata to provide an understanding of research evolution, key themes, relevant authors, and journals, as well as the country-wise distribution of authors’ affiliations. The selected articles were refined for a systematic literature review. A research framework was developed to classify the literature into common themes for easier navigation. The classification criteria include industry sectors, pipeline systems’ topologies, scheduling accuracy, parameter certainty, operation constraints, time and volume representations, solution strategies, and objectives. The results provide a comprehensive understanding of the field's current state and highlight promising directions for future research.</div></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"192 ","pages":"Article 108911"},"PeriodicalIF":3.9,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gianfranco Liberona , Alessandro Di Pretoro , Stéphane Negny , Ludovic Montastruc , David Salas
{"title":"Robustness in optimal design of Eco-Industrial Parks under the lens of two-stage stochastic optimization","authors":"Gianfranco Liberona , Alessandro Di Pretoro , Stéphane Negny , Ludovic Montastruc , David Salas","doi":"10.1016/j.compchemeng.2023.108399","DOIUrl":"https://doi.org/10.1016/j.compchemeng.2023.108399","url":null,"abstract":"<div><p>An eco-industrial park (EIP) is a community of businesses located together on a common property, that seek to reduce environmental and economical impact of their operation by collaborating and sharing materials and wastes. In practice, operations within an EIP have daily variations, and therefore are constantly facing uncertainty. In this work, a methodology to design efficient EIPs that are also <em>robust</em><span><span> to daily (uncertain) variations of the nominal operation of the enterprises is proposed. The attention is mainly focused in water exchange networks. Probability functions are used to </span>measure robustness and propose a Sample Average Approximation technique to solve the associated optimization problem. Simulations based on literature examples are performed to illustrate the approach.</span></p></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"179 ","pages":"Article 108399"},"PeriodicalIF":4.3,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6709485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prakitr Srisuma , George Barbastathis , Richard D. Braatz
{"title":"Analytical solutions for the modeling, optimization, and control of microwave-assisted freeze drying","authors":"Prakitr Srisuma , George Barbastathis , Richard D. Braatz","doi":"10.1016/j.compchemeng.2023.108318","DOIUrl":"https://doi.org/10.1016/j.compchemeng.2023.108318","url":null,"abstract":"<div><p>Freeze drying, aka lyophilization, is a process by which a pharmaceutical product is dried via sublimation under vacuum. An alternative to the conventional process is microwave-assisted freeze drying, which relies on microwave irradiation for drying the product, offering a reduction in the drying time by 70%–80%. This article derives exact and approximate analytical solutions to a mechanistic model for conventional, microwave-assisted, and hybrid freeze drying. The exact solution serves as a reference solution for validating numerical or approximate results due to its highest accuracy up to machine precision. The approximate solution can be computed about 4-fold faster than the numerical solutions and 200-fold faster than the exact solution with the maximum error of less than 1%, which is highly computationally efficient and accurate. Applications of the analytical solutions are demonstrated in the context of parameter estimation, optimal control, and parameter space analysis.</p></div>","PeriodicalId":286,"journal":{"name":"Computers & Chemical Engineering","volume":"177 ","pages":"Article 108318"},"PeriodicalIF":4.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1748463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}