Journal of advanced manufacturing and processing最新文献

Processing of liquid silicone rubber (LSR) in the injection molding process has a high economic potential. Since there are some fundamental differences compared to classical thermoplastic injection molding, up to now there is a lack of well-founded knowledge of the process which allows an estimation of the cycle time. Because, in addition to reverse temperature control, LSR processing also involves an irreversible temperature- and time-dependent chemical reaction. In this paper, the complex cross-linking reaction is first modelled phenomenologically using dynamic differential scanning calorimetry (DSC) measurements and the well-fitting Kamal-Sourour model. Afterwards, a temperature and cross-linking simulation is set up, which reliably simulates the time- and travel-dependent temperature profile and degree of cross-linking in the mold. Therefore, the released exothermic cross-linking heat is also taken into account. The simulated temperature values are verified with measurements in the cavity during the injection molding process. The measured values correspond very well with the simulated values at different mold temperatures. It is shown that the influence of the cross-linking heat on the overall temperature profile in the LSR component during the injection molding process is relatively low. Nevertheless, the model is necessary to determine the degree of cross-linking - it can be used to calculate the cycle time at which the component of a certain cross-section can be ejected at a known tool temperature and is fully cross-linked. With this knowledge, existing processes can be optimized in terms of mold temperature and curing time, but also new components can be calculated economically.

Additive manufacturing by 3D printing comprises a set of methods for production of 3D objects starting from a CAD file. Advantages of additive manufacturing combine high manufacturing resolution, a reduction of waste material, and the possibility of computer-aided design (CAD). When applied to the manufacturing of structured catalyst substrates, the latter enables the optimization of transport properties of the catalyst support. Despite several methods have been introduced for a variety of materials, copper, well known for its high thermal conductivity, is still difficult to be handled. In this work, a novel approach for the additive manufacturing of copper periodic open cellular structures (POCS) is proposed and investigated. It consists in the use of the replica manufacturing procedure starting from resin supports produced by 3D printing stereolithography. Micrometric high purity copper powder was effectively dispersed using a liquid medium based on organic components; the resulting slurry was used for the washcoat deposition on the resin supports. Structures with diamond unit cell shape (cell size of 2.5 mm and void fractions in the 0.8-0.9 range) were washcoated by dip-spin coating. Homogeneous washcoat layers were obtained without occurrence of cell clogging phenomena. Optimized thermal treatment procedure was assessed for sintering the copper POCS. The resulting matrices preserved the morphology of the original structure, reaching a resolution in the range of 70 to 120 μm. These materials can eventually be used as catalyst supports for heat-transfer limited applications (eg, steam reforming of methane), where copper-based substrates were demonstrated to be an effective solution for process intensification.

An amine solvent that undergoes phase change after absorption of CO₂ has been studied to reduce the energy consumed during the CO₂ capture process. Depending on the components of the solvent, the CO₂-rich phase can be separated for the regeneration step or the component in CO₂-lean phase accelerates the regeneration step in the solvent that undergoes liquid-liquid phase change. Since the homogeneous solvent separates into two liquid phases after CO₂ absorption, an analysis method to track the change in chemical species during the absorption process, especially at the phase separation time, is necessary to illuminate the phenomenon. To establish an online method to analyze the components of the solvent, a Fourier-transform infrared (FT-IR) spectrometer equipped with an attenuated total reflection (ATR) probe was used during the CO₂ absorption of phase separation solvent composed of amine, ether, and water. The calibration samples of amines, ethers, and CO₂-loaded solutions were used to develop the partial least square regression model. The consumption of reactants, as well as the formation of products, can be monitored quantitatively using the FT-IR spectra. Utilizing this information, the changes in the chemical species shed light on the phase separation mechanism of this solvent: ether was pushed out of the solvent to form a CO₂-lean phase due to its hydrophobicity, while CO₂ and its products along with amine and water remain in the CO₂-rich phase. Without sampling, this rapid and high-accuracy method is suitable for closed processes, especially for a high-pressure process.

This research is to produce the first quantitative evaluation, using global warming potential (GWP, kg CO₂ eq), of all published cradle-to-gate life cycle studies that compare reusable vs single-use products. We seek to determine whether there are consistent and fundamental factors that differentiate disposable and reusable products. A comparative assessment was made of the cradle-to-gate life cycle analyses of all published comparisons of reusable and single-use products from 1990 to 2016. A literature search found only 20 products in which a full life cycle analysis of cradle-to-gate (supply chain, manufacturing, reprocessing, and packaging of the reusable item) and supply chain plus manufacturing for the disposable had been published. GWP or carbon footprint was used as the environment comparison metric to which we added energy for the product manufacturing metrics. In this diverse set of products, the reusable product was consistently lower in cradle-to-gate energy use and global warming potential than the comparable single-use product. However, no apparent product characteristic appeared to govern the extent by which the reusable had a lower carbon footprint. These compelling results were compared with two other references in which disposable products were reported as better. However, when the data were reviewed with those authors, they reevaluated and found errors in calculations and corrected the results to then identify the lower reusable GWP impact compared to the respective disposable. The diversity of products studied and the consistently lower GWP impact of reusable products herein may suggest that products with reusable/disposable options could be predicted to show that the reusable is better than the single-use option.

Overcoming pandemics, such as the current Covid-19 outbreak, requires the manufacture of several billion doses of vaccines within months. This is an extremely challenging task given the constraints in small-scale manufacturing for clinical trials, clinical testing timelines involving multiple phases and large-scale drug substance and drug product manufacturing. To tackle these challenges, regulatory processes are fast-tracked, and rapid-response manufacturing platform technologies are used. Here, we evaluate the current progress, challenges ahead and potential solutions for providing vaccines for pandemic response at an unprecedented scale and rate. Emerging rapid-response vaccine platform technologies, especially RNA platforms, offer a high productivity estimated at over 1 billion doses per year with a small manufacturing footprint and low capital cost facilities. The self-amplifying RNA (saRNA) drug product cost is estimated at below 1 USD/dose. These manufacturing processes and facilities can be decentralized to facilitate production, distribution, but also raw material supply. The RNA platform technology can be complemented by an a priori Quality by Design analysis aided by computational modeling in order to assure product quality and further speed up the regulatory approval processes when these platforms are used for epidemic or pandemic response in the future.

This article uses case studies to demonstrate the potential of smart manufacturing (SM) and Internet of Things (IoT) technologies to enhance operational performance and productivity in industry. The analysis highlights benefits such as cost reduction, production flexibility, shorter product time-to-market, energy/water efficiency and environmental impact reduction, and increased productivity. To illustrate the effectiveness of SM and IoT approaches, the authors sought out manufacturers currently implementing or seeking to implement SM and IoT technologies. The authors identified beer brewing (NAICS Code 312120) as a rapidly expanding industry whose members appear eager to implement SM technologies to optimize production lines by revealing bottlenecks and identifying performance-reducing nodes. This article presents two case studies based on SM and IoT technologies in breweries. It briefly describes a systematic framework introduced elsewhere by the authors and uses it to assess the energy productivity and competitiveness of SM applications in breweries. This article addresses questions concerning the information and communications technology infrastructure needed to build smart breweries and how corporations simplify the installation and deployment of SM and IoT components. This article was originally published in the Proceedings of the 2019 ACEEE Summer Study on Energy Efficiency in Industry.

Increasing economic and environmental challenges leads to the need for changes in the chemical industry. In this context, a promising approach is utilizing flexible apparatuses and flexible plants to react to changing boundary conditions. However, the concept of flexibility in chemical engineering, which originated in manufacturing, still lacks a comprehensive organization and categorization of different types of flexibility. Thus, in this work, the origin of flexibility in manufacturing is traced, and a literature overview on flexibility in chemical engineering is provided. Based on a subsequent cluster analysis, four types of flexibility are identified and defined. Furthermore, this work enables research on flexibility to be integrated into a general and consistent definition of flexibility. The definitions are applied to examples from literature to achieve comparability. While enabling the qualitative assessment of flexibility, this work identifies open research gaps regarding the quantification of flexibility.

The COVID-19 pandemic has exposed fragilities and reinforced the resiliency of different elements of our manufacturing and processing systems. Food processing, in particular meat packing, currently a very labor-intensive operation, experienced significant disruption and the car industry implemented shutdowns which will ripple through supply chains in the coming months. It became clear that packaging supply chains are bottlenecks as producers tried to divert food stuffs from restaurants to consumer stores, and shifts in demand for paper products caused persistent consumer outages. The basic chemicals and fuels industry did not see significant disruption, but wild price fluctuations did occur as reduced demands and an unfortunately timed production increase caused available storage capacity to be strained. Recycling industries saw, and will continue to experience, both ends of the disruption as their consuming industries reduced demand and their providers stockpiled material or diverted it to trash. The beverage industry has significant inventory in public venues that has expired. Boutique level hand sanitizer production has resulted as these beverage production systems have been reconfigured and the rules surrounding the grade of alcohol relaxed.^[1]

We are sure there are many of you who have worked long hours to innovate your manufacturing and processing systems to cope with the challenges of COVID-19 and we would welcome articles and commentaries on how advanced manufacturing can play a role in our collective response. In this issue of JAMP we share a commentary on the rapid manufacturing of vaccines as our contribution to understanding how our community might respond to COVID-19,^[2] and we would like to encourage you to consider other ways in which our manufacturing systems will change in response to the pandemic. However, much as there is a need to address the short-term disruptions caused by a pandemic, and to understand how research can respond to create advanced manufacturing and processing systems with flexibility and resilience in the future, we also need to continue to push forward with efforts that provide new foundations for those features and we have curated articles that we hope fulfill that goal.

Process intensification remains a key approach to advanced manufacturing enabling more nimble and responsive systems. This issue provides two examples tackling a variety of processes: the epoxidation of vegetable oils and the manufacturing of butyl acrylate.

Rahim et al.^[3] show that by using a mesoscale oscillating baffled reactor the process can be converted from a batch operation to a continuous one and in the process they estimate that the new reactor is approximately 144 times smaller than the batch reactor operating at the same production rate.

The Simulated Moving Bed Reac

Coal power plants play an important role in supplying affordable and reliable electricity. It is necessary to develop high-efficiency and low-cost carbon capture (CC) technologies to mitigate the associated global warming. Using H₂S-tolerant oxygen transport membranes (OTMs) for hydrogen production and CO₂ separation can significantly reduce the energy penalty of CC in integrated gasification combined cycle (IGCC) power plants. We carried out system-level analysis to investigate a novel IGCC-CC power plant design using OTMs. We studied the impacts of various operating parameters on the overall efficiency and energy penalty. This novel IGCC-OTM system has an overall efficiency 3.2%-point lower than the same system without CC, much lower than the IGCC with water-gas shift reactors and acid gas removal units (IGCC-WGS) of 6.8%-point drop. The specific primary energy consumption for CO₂ avoided (SPECCA) of this novel technology is 1.08 MJ kgCO₂⁻¹, which is 59.4% lower than that of the IGCC-WGS.