Mechanical Properties and Microstructure of Multi-Materials Fabricated Through a Combination of LPBF and DED Additive Manufacturing Techniques

This research explores the use of different metals combined through 3D-printing to enhance the performance of materials, with a focus on making heat exchangers more cost-effective for renewable energy. The goal is to replace a costly high-temperature alloy with a more affordable low-temperature alloy, using metal additive manufacturing for its benefits such as less material waste, faster production, reduced weight, and the ability to print entire assemblies in one go. The study delves into a unique combination of two 3D-printing techniques, Directed Energy Deposition and Laser Powder-Bed Fusion, to create a multi-material composed of stainless steel 316L and a nickel-based superalloy, Inconel 625. The primary focus is on understanding the structure and properties of this material, documenting mechanical properties, and characterizing its microstructure. By investigating how these additive manufacturing techniques influence the material\u27s structure and properties, the research provides valuable insights on the fabrication of multi-materials. It expands our understanding of how combining different 3D-printing methods can enhance the production of multi-material components

Experiences from Experimental Mining in Brazil

The Experimental Mine (EM) of the Research Center of Responsible Mining of the University of São Paulo became the subject of investigation in a few years after its development ; it is an open-pit quarry currently exploiting marble and gneiss , used to produce industrial limestone and construction aggregates. It is a developing enterprise, dealing with the challenges of a technological upgrade from a small -scale operation to the characteristics of a medium -sized company. The Experimental Mine Project (EMP) was born to attend a double demand: to provide research and development (R&D ) support to a growing company and to provide experimental opportunity for a field of knowledge such as mining engineering that requires a large scale for its experiments. The main challenges of the EMP are related with the remaining small -scale mining features, such as large variety of equipment available, high level of operational flexibility, scarcity or absence of mine planning, being focused on daily operations. In such an environment, the first role of the EMP was to evaluate in a quantitative way the effects of unit operations over the whole mining process. The current excavation technique is by drilling and blasting. Many experimental campaigns have been conducted on site, with different purposes. One of the main research lines was to increase the productivity of the quarry by lowering production costs and improving the quality of the product, then optimizing the entire production cycle; the relationship between the unit costs of drilling and explosives were evaluated, as well as the link between the blast design and some factors affecting the downstream processing of the product. The paper describes the methods employed to conduct the research and the improvements to be pursued, with the due consideration to the influence and interference of the many parameters involved, from the rock-mass characteristics to the final products

The Music of Blasting

A common adage in the Explosives Industry goes by saying that "Blasting is not bombing". One of the key differences between the two employs of explosive energy lays in the same gap existing between the application of acoustic energy that differentiates noise from music: timing and the distribution of energization in time. While timing in blasting is widely accepted to influence blast induced vibrations, it is still not completely investigated when related to rock fragmentation and downstream benefits. This paper shows a research about this topic, developedon two phases: 1) test blasts at the Experimental Mine of the Research Center of Responsible Mining of the University of São Paulo; 2) development project for large-scale production blasts in an open-cast mine. The first phase of the research was performed attempting to increase the productivity of the experimental mine, by lowering production costs and improving the quality of the product. Some Key Performance Indicators (KPIs) were established to monitor the results. A new blast design method and a more appropriate initiation sequence were designed according to the principles of: i) decomposition of the blast; ii) taking advantage of the free surfaces to favor the movement of the blasted material; iii) simultaneous holes firing as far away as possible, to avoid undesired cooperation of charges that may induce the explosive energy to work with shear effect instead of producing fragmentation. The results show that the proper selection of delay timing leads to significant benefits for rock fragmentation, downstream processes and the quality of final walls. The second phase of the study was a research and development (R&D) project in an open-cast mine with the goal to achieve an average P80 of 300 mm (11,8”) in the run-of-mine (ROM) product without altering the existing budget. The project included several variables in the blast design that were not previously taken into account, such as the orientation of natural joint sets in the rock mass, specific energy of the explosive and firing sequence. The new blast design method considered the directions of natural joint sets and determined the drilling pattern and the firing sequence accordingly to favor the movement of the blasted rock along its preferential direction, to reduce its confinement. At the end of the project, it was achieved an average P80 of 304 mm (12”) in the ROM, 50% lower than the one at the beginning of the project. The final blast of the project showed a reduction of 3% of the drill and blast cost, employing the same powder factor and the same drill pattern size used at the beginning of the project. The results of this study show how blast performance is related to variables that are not contemplated in the most common design methods or fragmentation models: the firing sequence, the degree of freedom and the direction of movement in the blast

mRNA vaccines: a new opportunity for malaria, tuberculosis and HIV

The success of the first licensed mRNA-based vaccines against COVID-19 has created a widespread interest on mRNA technology for vaccinology. As expected, the number of mRNA vaccines in preclinical and clinical development increased exponentially since 2020, including numerous improvements in mRNA formulation design, delivery methods and manufacturing processes. However, the technology faces challenges such as the cost of raw materials, the lack of standardization, and delivery optimization. MRNA technology may provide a solution to some of the emerging infectious diseases as well as the deadliest hard-to-treat infectious diseases malaria, tuberculosis, and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), for which an effective vaccine, easily deployable to endemic areas is urgently needed. In this review, we discuss the functional structure, design, manufacturing processes and delivery methods of mRNA vaccines. We provide an up-to-date overview of the preclinical and clinical development of mRNA vaccines against infectious diseases, and discuss the immunogenicity, efficacy and correlates of protection of mRNA vaccines, with particular focus on research and development of mRNA vaccines against malaria, tuberculosis and HIV.info:eu-repo/semantics/publishedVersio

Microbial antigen identification and vaccine delivery systems

info:eu-repo/semantics/publishedVersio

Avaliação do desempenho do clone 3336 de Eucalyptus Urograndis na multiplicação e enraizamento in vitro.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Avaliação do efeito de diferentes agentes seletivos na regeneração de Eucalyptus grandis x E. urophylla.

Resumo