ADDITIVE MANUFACTURING RESEARCH LANDSCAPE: A LITERATURE REVIEW

Additive manufacturing offers several potentials such as the freedom of design, part consolidation, function integration, or time and cost-savings. These potentials make AM interesting for industries such as aerospace, automotive and medical implants, and are also seen as enables for the creation of entirely new business models. Additive manufacturing has the potential to change the current manufacturing landscape substantially and has attracted much attention of industry and academia over the last decades.However, these developments require improvements concerning the technology itself and its successful implementation into the value creation chain. Driven by the promising market opportunities and upcoming technological developments, many research activities started.This paper presents a literature review of publications from the last 20 years. Based on this analysis, the evolution of the AM research landscape is portrayed. The research landscape is organised into four areas: machine and process, material, digital process chain and methodology. The paper summarises developments in each of these areas and concludes by presenting current and discussing future research topics.

Comprehensive Evaluation and Quantitative Research on the Living Protection of Traditional Villages from the Perspective of “Production–Living–Ecology”

Aiming at the current isolated, static protection method of traditional villages, a comprehensive evaluation system for the living protection of traditional villages has been constructed based on the land use function integration concept in “Production–Living–Ecology” (PLE). By combining the “horizontal” PLE coupling coordination analysis with the “vertical” correlation analysis of the elements at each layer, the comprehensive evaluation and quantitative analysis of six traditional villages of different types and grades in the Taihu Lake area are carried out to quantitatively reflect the interactive relationship and integration mechanism of PLE in traditional villages. The results show that: (1) The PLE development of traditional villages is a dynamic process. Even if the villages are close in the PLE score, they may be in different stages of PLE development and coupling coordination type. (2) The “living” function has the highest correlation with the coupling coordination degree of PLE, and it acts as the engine and bridge of benign interaction between the PLE. (3) Even if the national traditional villages have a favorable ecology background, they may not get high scores, or even fail in the PLE score. (4) Among the sub-indicators, the natural environmental characteristics, the ecological vitality of political organizations, and the level of human settlement facilities show a significant linear correlation with the PLE score. Additionally, the ecological vitality of political organizations is the strongest. It can be therefore concluded that a positive policy organization is an important guarantee for realizing the PLE integration of traditional villages.

A New Initialization Approach in Particle Swarm Optimization for Global Optimization Problems

Particle swarm optimization (PSO) algorithm is a population-based intelligent stochastic search technique used to search for food with the intrinsic manner of bee swarming. PSO is widely used to solve the diverse problems of optimization. Initialization of population is a critical factor in the PSO algorithm, which considerably influences the diversity and convergence during the process of PSO. Quasirandom sequences are useful for initializing the population to improve the diversity and convergence, rather than applying the random distribution for initialization. The performance of PSO is expanded in this paper to make it appropriate for the optimization problem by introducing a new initialization technique named WELL with the help of low-discrepancy sequence. To solve the optimization problems in large-dimensional search spaces, the proposed solution is termed as WE-PSO. The suggested solution has been verified on fifteen well-known unimodal and multimodal benchmark test problems extensively used in the literature, Moreover, the performance of WE-PSO is compared with the standard PSO and two other initialization approaches Sobol-based PSO (SO-PSO) and Halton-based PSO (H-PSO). The findings indicate that WE-PSO is better than the standard multimodal problem-solving techniques. The results validate the efficacy and effectiveness of our approach. In comparison, the proposed approach is used for artificial neural network (ANN) learning and contrasted to the standard backpropagation algorithm, standard PSO, H-PSO, and SO-PSO, respectively. The results of our technique has a higher accuracy score and outperforms traditional methods. Also, the outcome of our work presents an insight on how the proposed initialization technique has a high effect on the quality of cost function, integration, and diversity aspects.

Review and New Aspects in Combining Multipoint Moulding and Additive Manufacturing

Additive manufacturing has become a very important manufacturing method in the last years. With additive manufacturing, a higher level of function integration can be achieved compared to traditional manufacturing technologies. However, the manufacturing of larger parts leads to long construction times. A possible solution is the combination of multipoint moulding with additive manufactured form elements. This article reviews the state of technology for multipoint moulding and additive manufacturing. Moreover, the state of technology is analysed to outline the possibilities and challenges of combining both technologies. The review shows that there has been research on different challenges of the new production process. On the other hand, it turns out clearly that there are many open points at the intersections of both technologies. Finally, the areas where further research is necessary are described in detail.

Increase in high-lift devices efficiency of swept wing

The use of Fowler flaps and slotted slats in sweptwing aircraft is the standard solution to increase wing lift at take off and landing. In the literature this solution is known as a classical option of high-lift system of commercial subsonic aircraft. The results of numerical and experimental studies of some solutions intended to increase the efficiency of classical high-lift devices are presented. The concept of the trailing-edge devices called "the adaptive flap" is considered as a way to improve flap efficiency. The adaptive concept is characterized by the integration of spoiler downward deflection to the Fowler flap function. Integration of the spoiler with a movable flap provided an increase of lift in the linear region due to flaps deflected to a higher angle. The steeper upwash angle at a leading-edge device may be the reason of an early stall of the main wing. To protect the leading edge a slotted Kruger flap with streamline form has been used. Preliminary design of classical and improved high-lift systems included the determination of aerodynamic shapes and the optimized position for the high-lift devices. Aerodynamic analysis and design were carried out using 2D RANS Navier-Stokes method. A comparison of computed results has shown visible aerodynamic advantages of an improved high-lift system for maximum lift coefficient and refining the behavior of stall characteristics at high angles of attack. The results of wind tunnel tests of aircraft model with adaptive flap showed its effectiveness.

Genotype-Phenotype Features of Germline Variants of the TMEM127 Pheochromocytoma Susceptibility Gene: A 10-Year Update

Purpose This work aimed to evaluate genotype-phenotype associations in individuals carrying germline variants of transmembrane protein 127 gene (TMEM127), a poorly known gene that confers susceptibility to pheochromocytoma (PHEO) and paraganglioma (PGL). Design Data were collected from a registry of probands with TMEM127 variants, published reports, and public databases. Main Outcome Analysis Clinical, genetic, and functional associations were determined. Results The cohort comprised 110 index patients (111 variants) with a mean age of 45 years (range, 21-84 years). Females were predominant (76 vs 34, P < .001). Most patients had PHEO (n = 94; 85.5%), although PGL (n = 10; 9%) and renal cell carcinoma (RCC, n = 6; 5.4%) were also detected, either alone or in combination with PHEO. One-third of the cases had multiple tumors, and known family history was reported in 15.4%. Metastatic PHEO/PGL was rare (2.8%). Epinephrine alone, or combined with norepinephrine, accounted for 82% of the catecholamine profiles of PHEO/PGLs. Most variants (n = 63) occurred only once and 13 were recurrent (2-12 times). Although nontruncating variants were less frequent than truncating changes overall, they were predominant in non-PHEO clinical presentations (36% PHEO-only vs 69% other, P < .001) and clustered disproportionately within transmembrane regions (P < .01), underscoring the relevance of these domains for TMEM127 function. Integration of clinical and previous experimental data supported classification of variants into 4 groups based on mutation type, localization, and predicted disruption. Conclusions Patients with TMEM127 variants often resemble sporadic nonmetastatic PHEOs. PGL and RCC may also co-occur, although their causal link requires further evaluation. We propose a new classification to predict variant pathogenicity and assist with carrier surveillance.