Comparative study of residual stress prediction methods in additive manufacturing processes

The additive manufacturing (AM) of products involves various processes, such as raising the temperature of a work-piece (part) and substrate to the melting point and subsequent solidification, using a movable source of heat. The work piece is subjected to repeated cycles of heating and cooling. The main objective of this work was to present an overview of the various methods used for prediction of the residual stresses and how their contributions can be used to improve current additive manufacturing methods. These novel methods of manufacturing have several merits, compared to conventional methods. Some of these merits include the lower costs, higher precision and accuracy of manufacturing, faster processing time and more eco-friendly approaches to processes involved.

Estimation of Position and Size of a Contaminant in Aluminum Casting Using a Thin-Film Magnetic Sensor

Advanced manufacturing processes require an in-line full inspection system. A nondestructive inspection system able to detect a contaminant such as tool chipping was utilized for the purpose of detecting a defective product as well as damaged machine tools used to fabricate the product. In a previous study, a system able to detect magnetic tool steel chipping in conductive material such as aluminum was developed and tested. In this study, a method of position and size estimation for magnetic chipping was investigated and is described. An experimental confirmation of the proposed method was also carried out using an actual prototype system.

An Experimental Evaluation of Resistive Defects and Different Testing Solutions in Low-Power Back-Biased SRAM Cells

This paper compares different types of resistive defects that may occur inside low-power SRAM cells, focusing on their impact on device operation. Notwithstanding the continuous evolution of SRAM device integration, manufacturing processes continue to be very sensitive to production faults, giving rise to defects that can be modeled as resistances, especially for devices designed to work in low-power modes. This work analyzes this type of resistive defect that may impair the device functionalities in subtle ways, depending on the defect characteristics and values that may not be directly or easily detectable by traditional test methods. We analyze each defect in terms of the possible effects inside the SRAM cell, its impact on power consumption, and provide guidelines for selecting the best test methods.

Following the Thread: Elite Iconography on Weaving Objects at Poggio Civitate (Murlo)

Evidence for industrial scale production of numerous manufacturing processes has been attested in all phases of occupation at Poggio Civitate (Murlo). A subset of these, tools for the production of textiles and fibers, indicates that textile crafts were manufactured on a large scale as a part of a centralized and organized industry. These industrialized practices occurred within and around the monumental seventh and sixth century BCE complexes which displayed architectural decoration bearing iconographic themes that served to secure the positions of the aristocratic elites. This paper investigates the stamped decoration present on rocchetti and its relationship to the architectural decoration present on the monumental structures of the site. As small moveable objects used by members of the community, rocchetti present an opportunity to investigate the movement of elite images through the non-elite population of a community and their reception of aristocratic ideology presented in monumental structures.

Next-Generation Genetic and Fermentation Technologies for Safe and Sustainable Production of Food Ingredients: Colors and Flavorings

A growing human population is a significant issue in food security owing to the limited land and resources available for agricultural food production. To solve these problems, sustainable food manufacturing processes and the development of alternative foods and ingredients are needed. Metabolic engineering and synthetic biology can help solve the food security issue and satisfy the demand for alternative food production. Bioproduction of food ingredients by microbial fermentation is a promising method to replace current manufacturing processes, such as extraction from natural materials and chemical synthesis, with more ecofriendly and sustainable operations. This review highlights successful examples of bioproduction for food additives by engineered microorganisms, with an emphasis on colorants and flavors that are extensively used in the food industry. Recent strain engineering developments and fermentation strategies for producing selected food colorants and flavors are introduced with discussions on the current status and future perspectives. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Comparative Life Cycle Assessment of Safety Shoes Toe Caps Manufacturing Processes

Toe caps are fundamental components of safety footwear used to prevent injuries which can be caused by falling objects. They can be realized by exploiting different materials (metal, composites and plastics) and manufacturing processes (stamping, injection molding, compression molding, etc.). However, they have always to fulfill the stringent requirements of safety regulations. In addition, in order to guarantee an ergonomic use, they must be as light as possible. It is estimated that at least 300 million pairs of safety footwear, with 600 million of toe caps, end up in landfill or are incinerated every year. This huge amount of wastes generates a relevant environmental impact, mainly attributable to toe caps manufacturing. In this context, it is important to develop new solutions which minimize the environmental impacts of toe caps manufacturing. Among others, the reuse of carbon fiber prepreg scraps has been recognized as a valid method to produce effective toe caps. In this paper, a detailed analysis of the environmental impacts associated to toe caps realized with reclaimed prepreg scraps has been conducted exploiting the Life Cycle Assessment methodology. The results have been compared to those obtained by analyzing toe caps realized in steel, aluminum, polycarbonate and glass fiber composite. Results demonstrate that the reclaim process for carbon fiber prepreg scraps can be a valid circular economy model to produce more sustainable toe caps for safety footwear.