Additive manufacturing (AM) has revolutionized production across industries, yet challenges persist in achieving optimal part quality. This paper studies the enhancement of post-processing techniques to elevate the overall quality of AM-produced components. This study focuses on optimizing various post-processing methodologies to address prevalent issues such as surface roughness, dimensional accuracy, and material properties. Through an extensive review, this article identifies and evaluates a spectrum of post-processing methods, encompassing thermal, chemical, and mechanical treatments. Special attention is given to their effects on different types of additive manufacturing technologies, including selective laser sintering (SLS), fused deposition modeling (FDM), and stereolithography (SLA) and their dedicated raw materials. The findings highlight the significance of tailored post-processing approaches in mitigating inherent defects, optimizing surface finish, and enhancing mechanical properties. Additionally, this study proposes novel post-processing procedures to achieve superior quality while minimizing fabrication time and infrastructure and material costs. The integration of post-processing techniques such as cleaning, surface finishing, heat treatment, support structure removal, surface coating, electropolishing, ultrasonic finishing, and hot isostatic pressing (HIP), as steps directly within the additive manufacturing workflow can immensely contribute toward this direction. The outcomes displayed in this article not only make a valuable contribution to the progression of knowledge regarding post-processing methods but also offer practical implications for manufacturers and researchers who are interested in improving the quality standards of additive manufacturing processes.

Additive manufacturing has been widely used in various industries, including the healthcare sector. Over the last few decades, AM has been playing an important role in the medical field in different areas, including surgical planning, implants, and educational activities. For surgical applications, AM can help surgeons practice and plan an operation until they are confident with the process. This can help to reduce operational risk and time. In addition, it can help to demonstrate the problem to other colleagues. AM has also been used to produce 3D models to teach students and doctors about human anatomy. This paper aims to comprehensively review the diverse applications of additive manufacturing within the domains of surgical planning and medical education. By focusing on the multifaceted roles played by AM in these critical areas, a contribution to the growing body of knowledge that underscores the transformative potential of this technology in shaping the future of healthcare practices is sought to be made.

Powder packing in metal powders is an important aspect of additive manufacturing (otherwise known as 3-D printing), as it directly impacts the physical and mechanical properties of materials. Improving the packing density of powder directly impacts the microstructure of the finished 3D-printed part and ultimately enhances the surface finish. To obtain the most efficient packing of a given powder, different powder blends of that material must be mixed to minimize the number of voids, irrespective of the irregularities in the particle morphology and flowability, thereby increasing the density of the powder. To achieve this, a methodology for mixing powder must be developed, for each powder type, to obtain the maximum packing density. This paper presents a model that adequately predicts the volumetric fraction of the powder grades necessary for obtaining the maximum packing density for a given powder sample. The model factors in the disparity between theoretical assumptions and the experimental outcome by introducing a volume reduction factor. We outline the model development steps in this paper, testing it with a real-world powder system.

The traditional hydrophobic solarevaporator is generally obtained through the modification of alkyl or fluoroalkyl on the photothermal membrane. However, the modified groups can easily be oxidized in the long-term use process, resulting in the poor salt resistance and stability of photothermal membrane. In order to solve this problem, a simple polypyrrole/polyvinylidene fluoride membrane, consisting of an intrinsic hydrophobic support (polyvinylidene fluoride) and a photothermal material (polypyrrole), was fabricated by ultrasonically mixing and immersed precipitation. This photothermal membrane showed good self-floating ability in the process of water evaporation. In order to further improve the photothermal conversion efficiency, a micropyramid structure with antireflective ability was formed on the surface of membrane by template method. The micropyramids can enhance the absorption efficiency of incident light. The water evaporation rate reached 1.42 kg m⁻² h⁻¹ under 1 sun irradiation, and the photothermal conversion efficiency was 88.7%. The hydrophobic polyvinylidene fluoride ensures that NaCl cannot enter into membrane during the evaporation process of the brine, thus realizing the stability and salt resistance of polypyrrole/polyvinylidene fluoride in 3.5%wt and 10%wt NaCl solution.

The Internet of Things (IoT) connects billions of heterogeneous devices, necessitating lightweight, efficient, and secure communication protocols to support a diverse range of use cases. While physical and network-layer technologies enable connectivity, transport and application-layer protocols determine how IoT devices exchange, manage, and secure information. The diverse and constrained nature of IoT devices presents a challenge in selecting appropriate communication protocols, with no one-size-fits-all solution existing. This article provides a comprehensive review of key transport and application protocols in IoT, including MQTT, MQTT-SN, CoAP, LwM2M, AMQP, XMPP, WebSockets, HTTP/HTTPS, and OPC UA. Each protocol is examined in terms of its design principles, communication patterns, reliability mechanisms, and security features. The discussion highlights their suitability for different deployment scenarios, ranging from resource-constrained sensor networks to industrial automation and cloud-integrated consumer devices. By mapping protocol characteristics to IoT requirements, such as scalability, interoperability, power efficiency, and manageability, the article provides guidelines for selecting the optimal protocol stack to optimize IoT system performance and long-term sustainability. Our analysis reveals that while MQTT dominates cloud telemetry, CoAP and LwM2M are superior in IP-based constrained networks, and emerging solutions like OSCORE are critical for end-to-end security.

This paper presents aspects of the concept and design of prostheses for the upper limb. The objective of this research is that of prototyping a customized prosthesis, with EMG signals that initiate the motion. The prosthesis’ fingers’ motions (as well as that of its hand and forearm parts) are driven by micro-motors, and assisted by the individualized command and control system. The software and hardware tandem concept of this mechatronic system enables complex motion (in the horizontal and vertical plane) with accurate trajectory and different set rules (gripping pressure, object temperature, acceleration towards the object). One important idea is regarding customization via reverse engineering techniques. Due to this, the dimensions and appearance (geometric characteristics) of the prosthesis would look like the human hand itself. The trajectories and motions of the fingers, thumbs, and joints have been studied by kinematic analysis with the matrix–vector method aided by Matlab. The concept and design of the mechanical parts allow for complex finger motion—rotational motion in two planes. The command and control system is embedded, and data received from the sensors are processed by a micro-controller for managing micro-motor control. Preliminary testing of the sensors and micro-motors on a small platform, Arduino, was performed. Prototyping of the mechanical components has been a challenge because of the high accuracy needed for the geometric precision of the parts. Several techniques of rapid prototyping were considered, but only DLP (digital light processing) proved to be the right one.