scholarly journals Analytical and Numerical Models of Thermoplastics: A Review Aimed to Pellet Extrusion-Based Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3160
Author(s):  
Alessio Pricci ◽  
Marco D. de Tullio ◽  
Gianluca Percoco
Keyword(s):  
Fluid Dynamics ◽  
Additive Manufacturing ◽  
Numerical Models ◽  
Fused Filament Fabrication ◽  
First Case ◽  
Recent Developments ◽  
Physical And Chemical ◽  
Pellet Extrusion ◽  
Selection Of ◽  
Reduction Of Costs

Recent developments in additive manufacturing have moved towards a new trend in material extrusion processes (ISO/ASTM 52910:2018), dealing with the direct extrusion of thermoplastic and composite material from pellets. This growing interest is driven by the reduction of costs, environmental impact, energy consumption, and the possibility to increase the range of printable materials. Pellet additive manufacturing (PAM) can cover the same applications as fused filament fabrication (FFF), and in addition, can lead to scale towards larger workspaces that cannot be covered by FFF, due to the limited diameters of standard filaments. In the first case, the process is known as micro- or mini-extrusion (MiE) in the literature, in the second case the expression big area additive manufacturing (BAAM) is very common. Several models are available in literature regarding filament extrusion, while there is a lack of modeling of the extrusion dynamics in PAM. Physical and chemical phenomena involved in PAM have high overlap with those characterizing injection molding (IM). Therefore, a systematic study of IM literature can lead to a selection of the most promising models for PAM, both for lower (MiE) and larger (BAAM) extruder dimensions. The models concerning the IM process have been reviewed with this aim: the extraction of information useful for the development of codes able to predict thermo-fluid dynamics performances of PAM extruders.

Additive manufacturing of zirconia parts by fused filament fabrication and solvent debinding: Selection of binder formulation

2019 ◽  
Vol 26 ◽  
pp. 117-128 ◽  
Author(s):  
Santiago Cano ◽  
Joamin Gonzalez-Gutierrez ◽  
Janak Sapkota ◽  
Martin Spoerk ◽  
Florian Arbeiter ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Fused Filament Fabrication ◽  
Selection Of

scholarly journals Integration of Topology Optimisation and Design Variants Selection for Additive Manufacturing-Based Systematic Product Redesign

2020 ◽  
Vol 10 (21) ◽  
pp. 7841
Author(s):  
Enrico Dalpadulo ◽  
Francesco Gherardini ◽  
Fabio Pini ◽  
Francesco Leali
Keyword(s):  
Additive Manufacturing ◽  
Assistive Device ◽  
Topology Optimisation ◽  
Fused Filament Fabrication ◽  
Parameters Selection ◽  
Critical Issues ◽  
Product And Process ◽  
Definition Of ◽  
Manufacturing Technologies ◽  
Selection Of

The development of additive manufacturing allows the transformation of technological processes and the redesign of products. Among the most used methods to support additive manufacturing, the design can be optimised through the integration of topology optimisation techniques, allowing for creating complex shapes. However, there are critical issues (i.e., definition of product and process parameters, selection of redesign variants, optimised designs interpretation, file exchange and data management, etc.) in identifying the most appropriate process and set-ups, as well as in selecting the best variant on a functional and morphological level. Therefore, to fully exploit the technological potentials and overcome the drawbacks, this paper proposes a systematic redesign approach based on additive manufacturing technologies that integrate topology optimisation and a tool for selecting design variants based on the optimisation of both product and process features. The method leads to the objective selection of the best redesigned configuration in accordance with the key performance indicators (KPIs) (i.e., functional and production requirements). As a case study, the redesign of a medical assistive device is proposed, previously developed in fused filament fabrication and now optimised for being 3D printed with selective laser melting.

What Can Digitization Do For Formulated Product Innovation and Development

2020 ◽  
Author(s):  
James McDonagh ◽  
William Swope ◽  
Richard L. Anderson ◽  
Michael Johnston ◽  
David J. Bray
Keyword(s):  
High Performance ◽  
Quality Data ◽  
High Quality Data ◽  
Base Level ◽  
Hybrid Approaches ◽  
Digital Ecosystem ◽  
Recent Developments ◽  
Chemical Simulation ◽  
High Level ◽  
Physical And Chemical

Digitization offers significant opportunities for the formulated product industry to transform the way it works and develop new methods of business. R&D is one area of operation that is challenging to take advantage of these technologies due to its high level of domain specialisation and creativity but the benefits could be significant. Recent developments of base level technologies such as artificial intelligence (AI)/machine learning (ML), robotics and high performance computing (HPC), to name a few, present disruptive and transformative technologies which could offer new insights, discovery methods and enhanced chemical control when combined in a digital ecosystem of connectivity, distributive services and decentralisation. At the fundamental level, research in these technologies has shown that new physical and chemical insights can be gained, which in turn can augment experimental R&D approaches through physics-based chemical simulation, data driven models and hybrid approaches. In all of these cases, high quality data is required to build and validate models in addition to the skills and expertise to exploit such methods. In this article we give an overview of some of the digital technology demonstrators we have developed for formulated product R&D. We discuss the challenges in building and deploying these demonstrators.<br>

Development and Applications of a Wellhead Protection Area Delineation Computer Program

1991 ◽  
Vol 24 (11) ◽  
pp. 51-62 ◽  
Author(s):  
N. Guiguer ◽  
T. Franz
Keyword(s):  
Case History ◽  
Numerical Models ◽  
Groundwater Resources ◽  
Theoretical Background ◽  
Human Interaction ◽  
Wellhead Protection ◽  
First Case ◽  
Protection Area ◽  
And Storage ◽  
The Town

In the last few years, groundwater management has concentrated on the protection of groundwater quality. An increasing number of countries has adopted policies to protect vital groundwater resources from deterioration by regulating human interaction with the subsurface, the use of potential contaminants, land use restrictions, and waste transport and storage. One of the more common regulatory approaches to the protection of groundwater focuses on public water supplies to reduce the potential of human exposure to hazardous contaminants. Under the framework of the Safe Drinking Water Act amended by U.S. Congress in 1986, The U.S.EPA (1987) issued guidelines for the delineation of wellhead protection areas, recommending the use of analytical and numerical models for the identification of such areas. In this study, the theoretical background for the development of one such numerical model is presented. Two real-world applications are discussed: in the first case history, the model is applied to a Superfund Site in Puerto Rico as a tool for assessment of the effectiveness of a proposed pump-and-treat scheme for aquifer remediation. Based on simulation results for the evolution of the existing contaminant plume it was verified that such a scheme would not work with the proposed purging wells. The second case history is the delineation of a wellhead protection area in the Town of Littleton, Massachusetts, and subsequent design of a monitoring well network.

Oxford Studies in Metaethics Volume 15

2020 ◽  
Keyword(s):  
Philosophy Of Mind ◽  
Philosophy Of Language ◽  
Moral Realism ◽  
Ethical Theory ◽  
Philosophical Work ◽  
Moral Explanation ◽  
Recent Developments ◽  
Selection Of

This series is devoted to original philosophical work in the foundations of ethics. It provides an annual selection of much of the best new scholarship being done in the field. Its broad purview includes work being done at the intersection of ethical theory and metaphysics, epistemology, philosophy of language, and philosophy of mind. The chapters included in the series provide a basis for understanding recent developments in the field. Chapters in this volume explore topics including the nature of reasons, the tenability of moral realism, moral explanation and grounding, and a variety of epistemological challenges.

scholarly journals Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4254
Author(s):  
Paulina A. Quiñonez ◽  
Leticia Ugarte-Sanchez ◽  
Diego Bermudez ◽  
Paulina Chinolla ◽  
Rhyan Dueck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Thermomechanical Processing ◽  
Material Selection ◽  
Shape Memory Polymer ◽  
Fused Filament Fabrication ◽  
Materials Development ◽  
Thermoplastic Material ◽  
Polymer Systems ◽  
Injection Molded

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

scholarly journals Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications

2020 ◽  
Vol 18 (1) ◽  
pp. 1148-1166
Author(s):  
Ganjar Fadillah ◽  
Septian Perwira Yudha ◽  
Suresh Sagadevan ◽  
Is Fatimah ◽  
Oki Muraza
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Photocatalytic Oxidation ◽  
Low Cost ◽  
Synthesis Method ◽  
Chemical Oxidation ◽  
Magnetic Iron Oxide ◽  
Oxidation Processes ◽  
Recent Developments ◽  
Physical And Chemical

AbstractPhysical and chemical methods have been developed for water and wastewater treatments. Adsorption is an attractive method due to its simplicity and low cost, and it has been widely employed in industrial treatment. In advanced schemes, chemical oxidation and photocatalytic oxidation have been recognized as effective methods for wastewater-containing organic compounds. The use of magnetic iron oxide in these methods has received much attention. Magnetic iron oxide nanocomposite adsorbents have been recognized as favorable materials due to their stability, high adsorption capacities, and recoverability, compared to conventional sorbents. Magnetic iron oxide nanocomposites have also been reported to be effective in photocatalytic and chemical oxidation processes. The current review has presented recent developments in techniques using magnetic iron oxide nanocomposites for water treatment applications. The review highlights the synthesis method and compares modifications for adsorbent, photocatalytic oxidation, and chemical oxidation processes. Future prospects for the use of nanocomposites have been presented.

scholarly journals CFD Investigation of Trout-Like Configuration Holding Station near an Obstruction

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 204
Author(s):  
Kamran Fouladi ◽  
David J. Coughlin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Laboratory Experiment ◽  
Numerical Models ◽  
Interaction Model ◽  
Underwater Vehicle ◽  
Water Stream ◽  
Hydrodynamic Analysis ◽  
Structure Interaction ◽  
Vehicle Systems

This report presents the development of a fluid-structure interaction model using commercial Computational fluid dynamics software and in-house developed User Defined Function to simulate the motion of a trout Department of Mechanical Engineering, Widener University holding station in a moving water stream. The oscillation model used in this study is based on the observations of trout swimming in a respirometry tank in a laboratory experiment. The numerical simulations showed results that are consistent with laboratory observations of a trout holding station in the tank without obstruction and trout entrained to the side of the cylindrical obstruction. This paper will be helpful in the development of numerical models for the hydrodynamic analysis of bioinspired unmanned underwater vehicle systems.

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