Journal of advanced manufacturing and processing最新文献

Mixing performance in a laminar flow with a mixing Reynolds number less than 10 is greatly affected by the geometry of the impeller blades, and how to generate axial flow is important. The authors developed a new AM impeller with a low production cost by combining simple pitched paddle impellers in multiple stages. In this study, we attempted to further optimize the shape of the AM impeller by adding an assisting blade. Mixing performance was compared between Newtonian and non-Newtonian fluids. The mixing performance of the multiple-pitched-paddle-impeller was improved by the assisting blades, but the partial helical ribbon impeller was ineffective, and the most efficient AM impeller was the partial helical ribbon impeller without assisting blades, so further impeller simplification was attempted and a modified new AM impeller with the most efficient and simple structure was developed, because the most efficient AM impeller was a partial helical ribbon impeller without assisting blades.

Multicollinearity and heterogeneity are prevalent challenges in the analysis of process industry datasets, necessitating algorithms capable of addressing both simultaneously. The partial least squares (PLS)-Tree algorithm, which integrates PLS regression with decision tree methodologies, stands out by concurrently addressing data heterogeneity and improving predictive performance. However, the PLS-Tree algorithm remains underexplored compared to other machine learning approaches. This study delves into the intricacies of the PLS-Tree algorithm, utilizing synthetic data that mirrors the complexity of real-world process industry scenarios characterized by high collinearity and clustering. This paper further enhances the original PLS-Tree framework by introducing multiple latent score vectors, with the objective of refining the clustering process and boosting predictive accuracy beyond that of standard PLS and regression tree algorithms. Additionally, a comparative analysis is presented, evaluating the performance of the enhanced PLS-Tree against regular PLS and regression tree, highlighting its potential for sophisticated data analysis in the process industries.

Poly(d,l-lactide) is a biocompatible and biodegradable polymer with applications in the biomedical field (drug delivery, implants) and packaging. Conventional synthesis with stannous octoate is slow (>4 h) and can climb to over 30 h. In order to reduce reaction times, we developed a microwave reactor process to ring-open polymerize d,l-lactide to form poly(d,l-lactide) in the presence of stannous octoate and an initiator, benzyl alcohol. We evaluated the suitability of toluene and tetrahydrofuran as solvents at 130, 150, and 170°C for the polymerization. Their respective dielectric loss $��\left(\epsilon ,″\right)�$ values are 0.1 and 0.35. Compounds with larger dielectric loss values are better at converting microwave energy to heat. The microwave's power input peaked at 420 W to reach 170°C with toluene, whereas with tetrahydrofuran the peak was 330 W; afterwards, the power input to maintain that temperature was 10 W for both solvents. A reaction in toluene at 170°C after 1 h produced poly(d,l-lactide) with a molecular weight of 31 kDa and a dispersity index of 1.5. In tetrahydrofuran, at the same temperature, the molecular weight peaked at 11 kDa after 4 h with a dispersity index of 1.2. Moreover, in the absence of microwaves the polymerization does not occur. Tetrahydrofuran is hygroscopic and water cleaves poly(d,l-lactide) chains resulting in a lower molecular weight despite the longer reaction time and larger dielectric loss compared to toluene, a water immiscible solvent.

This review presents the transformative potential of powder bed fusion (PBF) in manufacturing orthopedic implants, with a particular focus on β-Ti-Nb-based ternary and quaternary titanium alloys. These alloys, such as Ti–18Zr–14Nb, Ti–29Nb–13Ta–4.6Zr, and Ti–35Nb–7Zr–5Ta (TNZT), offer significant advantages over conventional materials like Co–Cr alloys and Ti–6Al–4V due to their lower Young's modulus, excellent biocompatibility, and reduced stress shielding effects. The review covers the period from 2015 to September 2024 and highlights advancements in PBF-fabricated β-Ti alloys, emphasizing their potential to improve implant longevity and patient outcomes by minimizing the risks of implant failure associated with conventional materials.

ReSpool is a transdisciplinary partnership among academia, government, industry, and nonprofit entities created in 2022 to develop and demonstrate a transferable model for the recycling of postconsumer textile and apparel waste into new textile products. ReSpool's engineering and creative teams have innovated proprietary technologies including the Fiber Shredder, which enables textile-to-fiber shredding for high-value applications, and a set of processes for the manufacture of yarns and nonwoven textiles from recycled fibers. ReSpool's circular supply chains begin with discarded clothing collected by Goodwill organizations in the two test regions and involves partnerships with Goodwill to recruit and train workers and install in-house recycling operations. ReSpool then works with textile manufacturers and home goods and apparel retailers on high-value applications through waste-led materials and product development. ReSpool takes a systems-based approach to sustainability research and problem-solving. This article briefly overviews the “systems thinking” framework and demonstrates how core principles of this framework structure the team's objectives, activities, and innovations. Finally, the article contributes to current debates regarding systems thinking and circularity by presenting a rationale for systems-based sustainability research and practice ratcheted to regional systems. By focusing on regional factors, connections, and opportunities, ReSpool aims to maximize its flexibility, relevance, and impact while enabling tailored replication of the model across diverse communities. In this way, ReSpool offers an innovative, circular materials model for the textile and apparel industries, turning textile waste into a source of business innovation, sustainable economic development, and skills training for communities across the country.

This report deals with the hydrodynamic and mass transport characterization in an rotating cylinder electrode (RCE) in continuous and batch configuration employing relatively simple techniques like obtaining the mixing time, polarization, and residence time distribution (RTD) curves. For batch configuration, the limiting current and Sh values were higher than for continuous configuration, indicating that the mixing pattern is influenced by possible flow inhomogeneities during the operation as a continuous mixing stirrer. This could diminish the amount of electroactive reactant that reaches the electrode surface, due to the possible shrinking of recirculation zones during the rotation of the cylindrical stirrer, forming channeling and by-pass flow zones. These results could evidence the existence of slight deviations from the ideal mixer and other non-ideality flow zones associated with the width of curves upon analyzing age function through RTD curves, at the different flow rates employed in continuous configurations.

Oscillatory baffled reactors have obtained increasing popularity over the last decades, due to their high mixing efficiency at low flow rates. Several studies were performed on the optimization of geometrical and operational parameters. Yet, a full overview about the interactions in between those parameters is still missing, which can be ascribed to the high number of geometrical and operational parameters that can be varied. In the present work, a central composite rotatable design was used to obtain an overview about the interactions in between the geometrical and operational parameters. Through 3D-printing, reactors were printed with high accuracy, assuring exact evaluation of geometrical effects on the flow. With particle image velocimetry the flow was characterized for effective mixing and the corresponding flow regime. The data obtained shows that the established optimization guidelines do not yield optimal operational conditions. Consequently, a new dimensionless number, the so called acceleration ratio $��\epsilon �$, was introduced to offer additional guidelines for efficient reactor design. Moreover, it was found that the classical oscillatory Reynolds number does not sufficiently characterize the flow regime. An alternative form was derived from the classical Reynolds number and verified by experimental data. Both, the limits of the newly introduced acceleration ratio and redefined oscillatory Reynolds number are in good accordance with CFD-results.

An industrial project based upon the multi-scale objective-oriented process development (MOPD) method for developing an optimum process for separating phenylenediamine (PDA) isomers was executed. This article reports the first four (4) steps of that project. In the first step, the solution for this separation problem was conceptualized. It is a distillation-crystallization-hybrid process. The second step is to validate the concept experimentally from the thermodynamic point of view followed by kinetic considerations. It was found that a 2-stage crystallization is required to purify the main product isomers to the desirable specification that is higher than 99.5 mol%. A heat and material balance model was then constructed for analyzing and optimizing various design variables, also used to understand the operability of the process. Finally, with proper HAZOP analysis and detailed engineering, the pilot unit was designed. Throughout the project, all exercises and efforts are well focused with clear objectives, hence there are minimum detours on the execution; furthermore, the clear objectives enhanced the communications among various disciplines tremendously. It is a valuable asset for senior management in the allocation of resources and budgets.

Mathematical modeling plays a diverse and crucial role in the chemical industry and academia. This manuscript describes how the physical and mechanical engineering disciplines help the commercialization of catalysts from evaluation to scale-up and manufacturing. Forming and shaping the catalyst is the first basic step in the catalyst manufacturing industry. Part A shows some of the classic process methods that are employed for this purpose. Catalyst extrudates require proper engineering and process control of their aspect ratio. Catalyst extrudates with a high aspect ratio tend to yield a low reactor fill due to a loose packing. Catalyst extrudates with a low aspect ratio tend to yield high pressure drop. Part B introduces the tensile strength of the catalyst in order to predict the aspect ratio of catalyst extrudates in commercial plants. A force-balance between the tensile strength of the catalyst and the impact forces due to collision experienced during manufacture leads to the dimensionless group $��B�e�$. The group $��B�e�$ allows to introduce and quantify the severity of equipment and the severity of entire commercial plants.