Increased Process Flexibility Research Articles

A surrogate‐based framework for feasibility‐driven optimization of expensive simulations

AbstractSurrogate‐based optimization approaches have been widely adopted in industrial problems due to their potential to reduce the number of simulation runs required in the optimization process. The surrogate‐based optimization framework has been extended to feasibility analysis in pharmaceutical manufacturing to characterize the design space. Most surrogate‐based approaches for feasibility analysis are limited to the construction of a regression model for the feasibility function. In this work, we developed a framework with the feasibility problem considered as a classification problem, and additional stages introduced to improve local exploitation and global exploration. We illustrate the efficiency of the proposed framework on three test problems and implement it in a realistic case study describing the production of solid‐based drugs using wet granulation, aimed to reduce the operation cost, improve product quality, and increase process flexibility and robustness.

Extracting liquid fertilizer from ammonia-laden pharmaceutical wastewater using Hollow fiber membrane contactors

Production of certain pharmaceuticals generates wastewater with a high ammonia load, posing economic and environmental burdens. Recovering ammonia as a nitrogen fertilizer can alleviate these burdens and is vital from a circular economy perspective. For this purpose, this study, jointly performed by a research university and a large pharma company, evaluated the use of Hollow fiber membrane contactors (HFMC). The experiments were conducted using real pharmaceutical wastewater in two separate laboratories at two process scales (bench and pilot) and two operating modes (batch and continuous). The study evaluated the effect of feed concentration, flow rate, and process configuration and described the results using a single-parameter (mass transfer coefficient K) mathematical model. We then used the model to design scaled-up batch and continuous processes, based on which we performed a detailed economic assessment. A robust and consistent ammonia removal and recovery were obtained for all the experimental conditions tested. The model adequately described the empirical results, and K was similar across all the experiments in this study, which were conducted in practically relevant conditions. Both batch and continuous process designs were found feasible, increasing process flexibility. The economic evaluation revealed that acid and base consumption, rather than the initial investment, is the most significant expense. The cost of membranes, although relatively high, had little contribution to the overall expenses. Revenues from selling the recovered nitrogen as ammonium-sulfate fertilizer reduces the evaluated net cost of the novel treatment to a minimum of $3.76 per kgN - a potential cost savings of up to 29% relative to the current treatment ($5.28). Therefore, applying HFMC to recover nitrogen from pharmaceutical wastewater is promising from both economic and environmental viewpoints.

Optimal scheduling of a large-scale power-to-ammonia process: Effects of parameter optimization on the indirect demand response potential

In the light of the increasing share of power generation from renewable energy sources, there is a growing interest in flexible operation of power-intensive processes for demand-side management/demand response. In this article, we investigate the potential application of a large-scale power-to-ammonia process in demand response programs. The process system under consideration consists of a polymer exchange membrane electrolysis that is optimally scheduled in accordance with day-ahead prices and a large-scale Haber–Bosch process that serves as a downstream energy storage. We apply a demand-side management framework with a sequential approach to identify the indirect demand response potential of the considered process system. Our results show that the power-to-ammonia process provides significant leverage for demand-side management. Moreover, we find that increasing process flexibility by optimizing operational parameters improves the demand response potential and that price profile dispersion can be used as an indicator to predict the economic performance of demand response scheduling.

Current advances on laser drying of electrodes for lithium-ion battery cells

From the automotive sector to medical technology, consumer electronics and other industries, the market share of battery-powered products is on the rise. Lithium-ion battery technology represents the majority of currently available rechargeable batteries. In order to further enhance the performance of lithium-ion technology while reducing production costs and decreasing the environmental footprint, it is necessary to continuously develop existing production technologies.The drying process of the viscous active material applied to the conductor films represents a significant process step in the electrode production due to the high energy input. In contrast to conventional drying processes, such as convection drying, the use of lasers for drying the active material of the electrodes offers advantages of high compactness and increased process flexibility combined with extremely high energy density. Additionally, laser drying technologies offer the possibility of increasing energy efficiency, which can be further improved by controlled energy deposition and spatially selective heat introduction.In this review, laser drying in electrode production is described in more detail and compared with state-of-the-art conventional drying technologies. Furthermore, potential possibilities for the application of different laser technologies in the production process of electrodes for lithium-ion batteries are investigated and basic scaling effects are derived.

Flexibility analysis for demand-side management in large-scale chemical processes: An ethylene oxide production case study

The increasing generation of electricity from renewables requires the stabilization of the grid but also offers the opportunity to reduce operating costs for electricity consumers. Chemical processes are favorable participants of this energy evolution due to their localized, high electricity demands. Large-scale continuous processes that do not have electricity as a primary feedstock are not commonly utilized as consumers. However, coupling these processes with fast-responding upstream processes that employ electricity as major feedstock can offer great potential for demand-side management (DSM). This research work provides a framework to assess DSM potentials tested on the ethylene oxide production process. Complex process modeling and simulation were employed. The conventional flexibility analysis approach was rethought to simultaneously perform system flexibility assessment and operating window optimization. Moreover, the detection of critical parameters was possible, which can be exploited to increase process flexibility. This work sets the basis for a flexible DSM optimization procedure.

Interruptions in Agile Software Development Teams

Agile approaches help software development project teams to better meet user needs and ensure flexibility in uncertain environments. But using agile approaches invites changes to the project and increases interactions between team members, which both cause interruptions in the workplace. While interruptions can help in task completion and increase process flexibility, they can also hinder employee productivity. We conducted an exploratory study of four agile software development teams. Our analysis identified (1) programming-related work impediments, (2) interaction-related interruptions, and (3) interruptions imposed by the external environment, which were managed by improved information retrieval and reduced team dependencies.

An integrated continuous downstream process with real-time control: A case study with periodic countercurrent chromatography and continuous virus inactivation.

Integrated continuous downstream processes with process analytical technology offer a promising opportunity to reduce production costs and increase process flexibility and adaptability. In this case study, an integrated continuous process was used to purify a recombinant protein on laboratory scale in a two-system setup that can be used as a general downstream setup offering multiproduct and multipurpose manufacturing capabilities. The process consisted of continuous solvent/detergent virus inactivation followed by periodic countercurrent chromatography in the capture step, and a final chromatographic polishing step. A real-time controller was implemented to ensure stable operation by adapting the downstream process to external changes. A concentration disturbance was introduced to test the controller. After the disturbance was applied, the product output recovered within 6 h, showing the effectiveness of the controller. In a comparison of the process with and without the controller, the product output per cycle increased by 27%, the resin utilization increased from 71.4% to 87.9%, and the specific buffer consumption was decreased by 21% with the controller, while maintaining a similar yield and purity as in the process without the disturbance. In addition, the integrated continuous process outperformed the batch process, increasing the productivity by 95% and the yield by 28%.

Thermal energy storage using phase change materials: Techno-economic evaluation of a cold storage installation in an office building

Utilizing the latent heat of solidification and melting of so-called phase change materials (PCMs) allows higher storage densities and increased process flexibility within energy systems. However, there is an existing gap in the current literature studying simultaneously the technical and economic performance of these thermal energy storages within an actual application. Thus, in this work a comprehensive techno-economic analysis of a full-scale storage with 7000 L salt-hydrate surrounding a polypropylene capillary tube heat exchanger is presented. The storage is located in a multi-story office building in Gothenburg, Sweden and is used for daily peak shaving of the building’s cooling energy demands. The daily utilizable storage capacity for the installation was determined to be 99kWh, which is 36% of the installed capacity given by the storage manufacturer. The major limiting factor were found to be 60–75% smaller charging rates than what was designed by the manufacturer. Using a mixed integer linear programming model (MILP) to yield optimum scheduling, the storage investment cost limit for a 5 year payback time can be estimated as 9804 SEK (≈ 921 EUR). These developed key performance indicators can be readily compared against alternative storage technologies and designs in order to select the optimal storage design for equivalent applications. Future work is needed to investigate reasons behind the lower than expected storage capacity.

Solvents, CO2 and biopolymers: Structure formation in chitosan aerogel

The functionality of biopolymer aerogels is inherently linked to its microstructure, which in turn depends on the synthesis protocol. Detailed investigations on the macroscopic size change and nanostructure formation during chitosan aerogel synthesis reveal a new aspect of biopolymer aerogels that increases process flexibility. Formaldehyde-cross-linked chitosan gels retain a significant fraction of their original volume after solvent exchange into methanol (50.3 %), ethanol (47.1 %) or isopropanol (26.7 %), but shrink dramatically during subsequent supercritical CO2 processing (down to 4.9 %, 3.5 % and 3.7 %, respectively). In contrast, chitosan gels shrink more strongly upon exchange into n-heptane (7.2 %), a low affinity solvent, and retain this volume during CO2 processing. Small-angle X-ray scattering confirms that the occurrence of the volumetric changes correlates with mesoporous network formation through physical coagulation in CO2 or n-heptane. The structure formation step can be controlled by solvent–polymer and polymer–drying interactions, which would be a new tool to tailor the aerogel structure.

A micropatterned substrate for on-surface enzymatic labelling of linearized long DNA molecules

Optical mapping of linearized DNA molecules is a promising new technology for sequence assembly and scaffolding, large structural variant detection, and diagnostics. This is currently achieved either using nanochannel confinement or by stretching single DNA molecules on a solid surface. While the first method necessitates DNA labelling before linearization, the latter allows for modification post-linearization, thereby affording increased process flexibility. Each method is constrained by various physical and chemical limitations. One of the most common techniques for linearization of DNA uses a hydrophobic surface and a receding meniscus, termed molecular combing. Here, we report the development of a microfabricated surface that can not only comb the DNA molecules efficiently but also provides for sequence-specific enzymatic fluorescent DNA labelling. By modifying a glass surface with two contrasting functionalities, such that DNA binds selectively to one of the two regions, we can control DNA extension, which is known to be critical for sequence-recognition by an enzyme. Moreover, the surface modification provides enzymatic access to the DNA backbone, as well as minimizing non-specific fluorescent dye adsorption. These enhancements make the designed surface suitable for large-scale and high-resolution single DNA molecule studies.

Optimization of traction unit for low-cost automated guided vehicle

AGV system already known today is commonplace in any large-scale production, warehousing or supply process logistics. System is not only increasing process flexibility but also the quality of products and services. They are unattended vehicles designed for towing, guiding and carrying various types of cargo using peripheral devices designed for these vehicles. The paper describes the design of the traction unit of the automated guided vehicle (AGV). The main goal of this design is optimization of traction unit for a low-cost version of commercial AGV and thereby reducing overall costs of equipment. The traction unit must be designed so that the equipment that uses such a type of traction unit meets customer requirements.

DALEC: a framework for the systematic evaluation of data-centric approaches to process management software

The increasing importance of data in business processes has led to the emergence of data-centric business process management, which deviates from the widely used activity-centric paradigm. Data-centric approaches set their focus on data, aiming at supporting data-intensive business processes and increased process flexibility. The objective of this article is to gain profound insights into the maturity of different data-centric approaches as well as their capabilities. In particular, this article will provide a framework for systematically evaluating and comparing data-centric approaches, with regard to the phases of the business process lifecycle. To this end, a systematic literature review (SLR) was conducted with the goal of evaluating the capabilities of data-centric process management approaches. The SLR comprises 38 primary studies which were thoroughly analyzed. The studies were categorized into different approaches, whose capabilities were thoroughly assessed. Special focus was put on the tooling and software of the approaches. The article provides the empirically grounded DALEC framework to evaluate and compare data-centric approaches. Furthermore, the results of the SLR offer insights into existing data-centric approaches and their capabilities. Data-centric approaches promise better support of loosely structured and data-intensive business processes, which may not be adequately represented by activity-centric paradigms.

Low‐temperature deposition of polycrystalline germanium on silicon by magnetron sputtering

A new method is reported to grow polycrystalline germanium (Ge) on silicon (Si) at low temperatures by direct current magnetron sputtering. The method is based on first sputtering a nanometre scale thickness Si layer on a Si substrate, followed by sputtering a Ge layer of the desired thickness. Using this approach, polycrystalline Ge has been deposited on Si substrate at 300°C, the lowest reported process temperature for polycrystalline Ge on Si by sputter coating. Characterisation by X-ray diffraction and Raman spectroscopy showed polycrystalline Ge in the presence of a Si interfacial layer. In the absence of the interfacial Si layer, amorphous Ge was obtained under the same process conditions. These observations indicate that depositing a Si interfacial layer helps in improving the Ge film quality in low-temperature deposition conditions. The approach developed here makes it possible to achieve post-CMOS integration in applications that have low thermal budget, such as flexible electronics based on Si/Ge devices. The increased process flexibility offered by this method is also expected to enable new applications.

Multivariate process capability analysis applied to AISI 52100 hardened steel turning

Hard turning operations have been extensively investigated owing to their ability to reduce process cycle time, increase process flexibility, ensure high-dimensional accuracy, and enable machining without a cutting fluid. These processes are rather common for dealing with multiple quality characteristics. To evaluate the process ability and meet customer needs, multivariate statistical techniques are recommended for estimating the capability indices. Principal component analysis can be applied to reducing the problem dimension and estimate process capability indices. The aim of this study was to assess the capability of AISI 52100 hardened steel turning operations and achieve process specifications. Multivariate process capability indices were calculated to assess five roughness parameters of surface finishing. By using a weighted approach of principal component analysis, a new method is proposed for estimating the process capability indices. The results highlight not only the relevance of conducting a multivariate capability analysis in the case of actual machining but also how successfully the proposed method was performed.

The role of biopreservation in cell and gene therapy bioprocessing

Cell and gene-based therapies represent a novel therapeutic modality that has the potential to provide a treatment option for a range of medical conditions. There are, however, numerous processing and manufacturing challenges that must be addressed before such therapies are considered commercially and clinically viable. A significant challenge associated with the manufacture of such therapies is ensuring cell quality and the product’s critical quality attributes are retained throughout the entire bioprocess. Biopreservation is an important aspect of cell and gene-based therapy bioprocessing, which enables the development of cell banks. It increases process flexibility by providing a shelf-life to the product, enables the storage of intermediates and provides breakpoints within the process. In this article, we summarize the advances and challenges associated with biopreservation of cell and gene therapies.

Benefit of Modern Arc Management in MF Dual Magnetron Sputtering Power Supplies

For modern large area coatings reactive dual magnetron sputtering (DMS) is a widespread technology. Economic constraints and advanced technology calls for increasing process flexibility regarding target utilization as well as the use of new materials. This in turn raises demands to the arc handling capabilities of the power supplies. On the one hand, a stable process at high arcing rates demands short arc blanking times and fast recovery to full output power. On the other hand, some materials tend to the formation of so-called “hard” arcs, with hot cathode spots. In this case, longer treatment times are needed. The benefit of modern arc handling capabilities is demonstrated for reactive SiO2 deposition from heavily used targets. For other demanding materials with low melting point, favourable operating modes are investigated.

Control of particle size, at micrometric and nanometric range, using supercritical antisolvent precipitation from solvent mixtures: Application to PVP

The control of particle size at micrometric and nanometric range is of relevant interest in many industrial applications. In this work, Supercritical AntiSolvent (SAS) precipitation, using solvent mixtures has been used to increase process flexibility in particle size control. The biopolymer polyvinylpyrrolidone (PVP) has been used as a model solute. PVP is slightly soluble in acetone (AC) and largely soluble in dimethylsulfoxide (DMSO), ethyl alcohol (EtOH) and N-methylpyrrolidone (NMP); therefore, solvent mixtures of AC and these other solvents have been used. The experiments using EtOH/AC solvent mixture were performed to study the effect of the solvation power alone, considering that both pure solvents show similar mixing behaviors with scCO2. Experiments using the solvent mixtures NMP/AC and DMSO/AC were performed to study both the influence of the solvation power and the influence of the jet/spray mixing behavior with supercritical carbon dioxide (scCO2) on the characteristics of the PVP precipitates.Using pure DMSO, NMP or EtOH, it is possible to produce spherical PVP microparticles (with a mean diameter lower than 3.8μm); whereas, using mixtures of these solvents with acetone, PVP nanoparticles (with a mean diameter down to 0.11μm) were precipitated.

Single-use perfusion bioreactors support continuous biomanufacturing

The field of biomanufacturing employs many single-use (SU) systems for features such as lower initial investment and reduced time-to-market. Continuous manufacturing methods can provide increased product quality and process control, and reduced operating costs. Continuous biomanufacturing (CB) additionally promises reduced classified area extent, personnel requirements and operating steps. The benefits of SU CB include heightened processing parameter consistency and increased process flexibility. Perfusion culture (PC) is supported by many specialized SU and hybrid bioreactors. These and many accessory perfusion-enabling technologies are the main way of implementing upstream CB. Valuable features provided by PC include reduced product reactor-residency and increased reactor-volumetric productivity. SU PC supports the dream of enterprise managed, modular, end-to-end integrated and closed CB providing higher environmental sustainability.

Laser-induced plasma micro-machining (LIPMM) for enhanced productivity and flexibility in laser-based micro-machining processes

This paper presents a new micro-machining process, laser-induced plasma micro-machining (LIPMM), in which plasma induced in a liquid at the focal point of the laser beam is used to perform micro-machining. It is shown that LIPMM can machine a variety of materials including metal alloys, polymers and ceramics. A process variant, line-LIPMM (L-LIPMM), based on optical manipulation of the laser beam to create line- instead of spot-plasma, is developed. Additionally, a second variant, magnetically-controlled LIPMM (MC-LIPMM), in which an external magnetic field is used to manipulate the shape of the plasma, is developed to further increase process throughput and flexibility.

Peel resistance characterization of localized polymer film bonding via thin film adhesive thermally activated by scanned CO2 laser

Thermal laser polymer bonding is a non-contact process for the joining of polymer laminates using thermally activated adhesives. Conventional, contact based bonding techniques suffer from mechanical wear, geometric inflexibility and poor energy efficiency. The application of lasers offers the potential for highly localized delivery of energy and increased process flexibility whilst achieving controlled and repeatable bonding of polymer laminates in a contact free process. Unlike previously reported techniques, here it is reported that laser based non-contact bonding is both viable and highly desirable due to the increased levels of control it affords the user.In this work, laser polymer bonding of 75μm thick linear low density polyethylene (LLDPE) film backed with a thermally activated adhesive to a 640μm thick polypropylene (PP) substrate was conducted using continuous wave 10.6μm laser radiation and scanning galvanometric optics. The effect of laser power and scanning traverse speed on the peel resistance properties of the bonded polymer laminates is presented, with a threshold specific energy density for successful adhesive activation determined.