Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

Machine Learning in Process Monitoring and Control for Wire-Arc Additive Manufacturing

Wire-arc additive manufacturing (WAAM) is an arc-based directed energy deposition approach that uses an electrical arc as a source of fusion to melt the wire feedstock and deposit layer by layer. It’s applicable in fabricating large-scale components. At this stage, there are still some issues that need to be researched deeply, such as manufacturing accuracy control, process parameters optimization, path planning, and online monitoring. Machine learning is a new emerging artificial intelligence technology, which is more and more applied in modern industry. In this study, a machine learning based control algorithm was applied in melt pool width control. To monitor the WAAM process, deep learning algorithms were applied in anomalies recognition. At the same time, machine learning methods were employed to predict the deposited surface roughness during the WAAM process

Integrating human expertise to optimize the fabrication of parts with complex geometries in WAAM

Wire arc additive manufacturing (WAAM) has emerged as a versatile solution for fabricating parts with complex geometries in recent years. However, the existing deposition parameter planning methods struggle to offer continuous and precise parameters when the part geometry varies dynamically due to the long-term dependence, strong coupling, and hysteresis properties of the WAAM process. To address this challenge, this research introduces an advanced algorithm for generating accurate and continuous deposition parameters by learning and utilizing the welding skills of proficient human welders. The first step involves capturing kinematic and welding parameter data from proficient human welders during practical welding processes. Following this, a human skill learning algorithm is developed based on a combination of the adaptive neuro-fuzzy inference system (ANFIS) architecture and particle swarm optimization (PSO) to analyse and model human motions and bead deposition results. Lastly, a practical backward model is established to generate continuous deposition parameters for weld beads with varying geometry. The effectiveness of the proposed algorithm is validated through the fabrication of two practical WAAM parts. The root mean square error (RMSE) values between the target geometry and the ground truth geometry of the parts are 0.1648 and 0.1805 respectively. The result demonstrates the algorithm\u27s superior ability in optimal deposition parameters planning for fabricating parts with complex geometries

Terahertz non-destructive imaging of cracks and cracking in structures of cement-based materials

Cracks and crack propagation in cement-based materials are key factors leading to failure of structures, affecting safety in construction engineering. This work investigated the application of terahertz (THz) non-destructive imaging to inspections on structures of cement-based materials, so as to explore the potential of THz imaging in crack detection. Two kinds of disk specimens made of plain cement mortar and UHMWPE fiber concrete were prepared respectively. A mechanical expansion load device was deployed to generate cracks and control the whole process of cracking. Experimental tests were carried out on cracked specimens by using a commercial THz time domain spectroscopy (THz-TDS) during loading. The results show that crack opening and propagation could be examined by THz clearly and the material factors influence the ability of crack resistance significantly. It was found that the THz imaging of crack initiation and propagation agrees with the practical phenomenon and supplies more information about damage of samples. It is demonstrated that the damage behavior of structures of cement-based materials can be successfully detected by THz imaging

Research and application of artificial intelligence techniques for wire arc additive manufacturing: a state-of-the-art review

Recent development in the Wire arc additive manufacturing (WAAM) provides a promising alternative for fabricating high value-added medium to large metal components for many industries such as aerospace and maritime industry. However, challenges stemming from the demand for increasingly complex and high-quality products, hinder the widespread adoption of the conventional WAAM method for manufacturing industries. The development of artificial intelligence (AI) techniques may provide new opportunities to upgrade WAAM to the next generation. Hence, this paper provides a comprehensive review of the state-of-the-art research on AI techniques in WAAM. Firstly, we proposed a novel concept of intelligent wire arc additive manufacturing (IWAAM) and revealed the challenges of developing IWAAM. Secondly, an overview of the research progress of applying AI techniques to several aspects of the WAAM process chain, including fabrication process pre-design, online deposition control and offline parameter optimization is provided. Thirdly, the relevant machine learning algorithms, and the knowledge of corresponding AI techniques, are also reviewed in detail. Through reviewing the current research articles, issues of applying AI techniques to the WAAM process are presented and analysed. Finally, future research perspectives in terms of novel AI technique applications and AI technique enhancement are discussed. Through this systematic review, it is expected that WAAM may gradually develop into a smart/intelligent manufacturing technology in the context of Industry 4.0 through the adoption of AI techniques