Characterization and Defect Analysis of Machined Regions in Al-SiC Metal Matrix Composites Using an Abrasive Water Jet Machining Process

Metal matrix composite (MMC) materials are increasingly used in industrial sectors such as energy, structural, aerospace, and automotive. This is due to the improvement of properties by the addition of reinforcements. Thus, it is possible to obtain properties of higher strength, better rigidity, controlled thermal expansion, and elevated wear resistance. However, due to the extreme hardness achieved during their manufacture, these composites pose a challenge to the conventional machining industry due to the rapid deterioration experienced by cutting tools. This article therefore proposes the use of an unconventional machining method that is becoming increasingly widely used: abrasive water jet cutting. This process is characterized by high production rates, absence of wear, and environmental friendliness, among other advantages. Experimental tests were carried out in order to analyze results that minimize the formation of defects in the machining of metal matrix composite consisting of aluminium matrix with silicon carbide (Al-SiC MMC). To this end, results were analyzed using Scanning Optical and Electron Microscope (SOM/SEM) techniques, the taper angle was calculated, and areas with different surface quality were detected by measuring the roughness

Evaluation of Reliefs’ Properties on Design of Thermoformed Packaging Using Fused Deposition Modelling Moulds

The increased consumption of food requiring thermoformed packaging implies that the packaging industry demands customized solutions in terms of shapes and sizes to make each packaging unique. In particular, food industry increasingly requires more transparent packaging, with greater clarity and a better presentation of the product they contain. However, in turn, the differentiation of packaging is sought through its geometry and quality, as well as the arrangement of food inside the packaging. In addition, these types of packaging usually include ribs in the walls to improve their physical properties. However, these ribs also affect the final aesthetics of the product. In accordance with this, this research study analyses the mechanical properties of different relief geometries that can affect not only their aesthetics but also their strength. For this purpose, tensile and compression tests were carried out using thermoformed PET sheets. The results provide comparative data on the reliefs studied and show that there are differences in the mechanical properties according to shape, size and disposition in the package

Custom Design of Packaging through Advanced Technologies: A Case Study Applied to Apples

In the context of food packaging design, customization enhances the value of a product by meeting consumer needs. Personalization is also linked to adaptation, so the properties of the packaging can be improved from several points of view: functional, aesthetic, economic and ecological. Currently, functional and formal properties of packaging are not investigated in depth. However, the study of both properties is the basis for creating a new concept of personalized and sustainable product. In accordance with this approach, a conceptual design procedure of packaging with personalized and adapted geometries based on the digitization of fresh food is proposed in this work. This study is based on the application of advanced technologies for the design and development of food packaging, apples in this work, in order to improve the quality of the packaging. The results obtained show that it is possible to use advanced technologies in the early stages of product design in order to obtain competitive products adapted to new emerging needs

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature

Influence of 3D-Printed TPU Properties for the Design of Elastic Products

The design of products with elastic properties is a paradigm for design engineers because the properties of the material define the correct functionality of the product. Fused filament fabrication (FFF) allows for the printing of products in thermoplastic polyurethanes (TPU). Therefore, it offers the ability to design elastic products with the freedom of forms that this technology allows and also with greater variation of elastic properties than with a conventional process. The internal structures and the variation in thickness that can be used facilitate the design of products with different elastic realities, producing variations in the elasticity of the product with the same material. This work studies the influence of the variation of internal density as a function of basic geometries in order to quantify the difference in elasticity produced on a product when it is designed. Likewise, a case study was carried out with the creation of a fully elastic computer keyboard printed in 3D. The specimens were subjected to compression to characterize the behavior of the structures. The tests showed that the elasticity varies depending on the orientation and geometry, with the highest compressive strength observed in the vertical orientation with 80% lightening. In addition, the internal lightening increases the elasticity progressively but not uniformly with respect to the solid geometry, and also the flat faces favour the reduction in elasticity. This study classifies the behavior of TPU with the aim of being applied to the design and manufacture of products with specific properties. In this work, a totally flexible and functional keyboard was designed, obtaining elasticity values that validate the study carried out.The APC was funded by University of Cadiz (programme for the promotion and encouragement of research and transfer)

Influence of the Fractal Geometry on the Mechanical Resistance of Cantilever Beams Designed through Topology Optimization

In this work, the complex geometry of beams obtained from topology optimization is characterized through the fractal dimension (F-D). The fractal dimension is employed as an efficiency measure of the mass distribution in the beams, that is, the capacity of the optimized solutions to be efficiently distributed in the design space. Furthermore, the possible relationships between the fractal dimension and beams' mechanical properties are explored. First, a set of theoretical beams are studied based on their well-known fractal dimension. A 3D fractal called Menger sponge is reproduced on a Michell's beam (cantilever with a single force applied at the end). The programming codes that generate those beams are created in Matlab software, as are the algorithms for estimating the fractal dimension (box-counting method). Subsequently, identical beams are modelled in the software Inspire in order to apply the topology optimization and determine the mechanical parameters from the static analysis. Results indicate that the fractal dimension is affected by the design geometry and proposed optimized solutions. In addition, several relationships among fractal dimension and some mechanical resistance parameters could be established. The obtained relations depended on the objectives that were initially defined in the topology optimization

Do Products Respond to User Desires? A Case Study. Errors and Successes in the Design Process, under the Umbrella of Emotional Design

This article introduces a methodological approach to the evaluation of different industrial products according to Norman's approach and dimensions, focusing on a specific case study. The study also shows different possibilities to guide industrial designers during the design process in order to create products with high emotional value. For those, the case study was done with 330 target specific users, submitting nine prototypes (designed for different targets) to the user experience evaluation and product perception analysis. The evaluated proposals were selected from a total of 45. The results show the visceral, behavioural and reflective levels perceived by those users to whom each product is intended, as well as the target deviation within the design process. In this sense, the emotional response reveals the asymmetric character of perception according to Norman's dimensions

Safety and immunogenicity of the protein-based PHH-1V compared to BNT162b2 as a heterologous SARS-CoV-2 booster vaccine in adults vaccinated against COVID-19 : a multicentre, randomised, double-blind, non-inferiority phase IIb trial

A SARS-CoV-2 protein-based heterodimer vaccine, PHH-1V, has been shown to be safe and well-tolerated in healthy young adults in a first-in-human, Phase I/IIa study dose-escalation trial. Here, we report the interim results of the Phase IIb HH-2, where the immunogenicity and safety of a heterologous booster with PHH-1V is assessed versus a homologous booster with BNT162b2 at 14, 28 and 98 days after vaccine administration. The HH-2 study is an ongoing multicentre, randomised, active-controlled, double-blind, non-inferiority Phase IIb trial, where participants 18 years or older who had received two doses of BNT162b2 were randomly assigned in a 2:1 ratio to receive a booster dose of vaccine-either heterologous (PHH-1V group) or homologous (BNT162b2 group)-in 10 centres in Spain. Eligible subjects were allocated to treatment stratified by age group (18-64 versus ≥65 years) with approximately 10% of the sample enrolled in the older age group. The primary endpoints were humoral immunogenicity measured by changes in levels of neutralizing antibodies (PBNA) against the ancestral Wuhan-Hu-1 strain after the PHH-1V or the BNT162b2 boost, and the safety and tolerability of PHH-1V as a boost. The secondary endpoints were to compare changes in levels of neutralizing antibodies against different variants of SARS-CoV-2 and the T-cell responses towards the SARS-CoV-2 spike glycoprotein peptides. The exploratory endpoint was to assess the number of subjects with SARS-CoV-2 infections ≥14 days after PHH-1V booster. This study is ongoing and is registered with , . From 15 November 2021, 782 adults were randomly assigned to PHH-1V (n = 522) or BNT162b2 (n = 260) boost vaccine groups. The geometric mean titre (GMT) ratio of neutralizing antibodies on days 14, 28 and 98, shown as BNT162b2 active control versus PHH-1V, was, respectively, 1.68 (p < 0.0001), 1.31 (p = 0.0007) and 0.86 (p = 0.40) for the ancestral Wuhan-Hu-1 strain; 0.62 (p < 0.0001), 0.65 (p < 0.0001) and 0.56 (p = 0.003) for the Beta variant; 1.01 (p = 0.92), 0.88 (p = 0.11) and 0.52 (p = 0.0003) for the Delta variant; and 0.59 (p ≤ 0.0001), 0.66 (p < 0.0001) and 0.57 (p = 0.0028) for the Omicron BA.1 variant. Additionally, PHH-1V as a booster dose induced a significant increase of CD4 + and CD8 + T-cells expressing IFN-γ on day 14. There were 458 participants who experienced at least one adverse event (89.3%) in the PHH-1V and 238 (94.4%) in the BNT162b2 group. The most frequent adverse events were injection site pain (79.7% and 89.3%), fatigue (27.5% and 42.1%) and headache (31.2 and 40.1%) for the PHH-1V and the BNT162b2 groups, respectively. A total of 52 COVID-19 cases occurred from day 14 post-vaccination (10.14%) for the PHH-1V group and 30 (11.90%) for the BNT162b2 group (p = 0.45), and none of the subjects developed severe COVID-19. Our interim results from the Phase IIb HH-2 trial show that PHH-1V as a heterologous booster vaccine, when compared to BNT162b2, although it does not reach a non-inferior neutralizing antibody response against the Wuhan-Hu-1 strain at days 14 and 28 after vaccination, it does so at day 98. PHH-1V as a heterologous booster elicits a superior neutralizing antibody response against the previous circulating Beta and the currently circulating Omicron BA.1 SARS-CoV-2 variants in all time points assessed, and for the Delta variant on day 98 as well. Moreover, the PHH-1V boost also induces a strong and balanced T-cell response. Concerning the safety profile, subjects in the PHH-1V group report significantly fewer adverse events than those in the BNT162b2 group, most of mild intensity, and both vaccine groups present comparable COVID-19 breakthrough cases, none of them severe. HIPRA SCIENTIFIC, S.L.U

Estudio epidemiológico de salud y maloclusión dental en niños de Bogotá, Colombia

En esta obra e aplica de manera determinante e! binomio inve - tigación-extensión, que hace parte de lo principios filosóficos y estructurales de la Universidad Nacional de Colombia. Se pudo así dar cumplimiento al deber ético, por ende hipocrático, de obrepa ar la barrera de! conocimiento en lo que concierne a nuestra pluralidad étnica, y a la vez enriquecer la cultura de la investigación en profesores y estudiantes de la actual y futuras generaciones