http://yetl.yabesh.ir/yetl1/handle/yetl/19059 Thu, 23 Apr 2026 09:20:51 GMT 2026-04-23T09:20:51Z http://localhost:80/yetl1/bitstream/id/184267/ http://yetl.yabesh.ir/yetl1/handle/yetl/19059 http://yetl.yabesh.ir/yetl1/handle/yetl/4310414 A New Surface Finishing Process for Quartz Glass Rotary Parts Based on Changes in Wetting State Liu, Yujie; Tong, Hao; Tan, Qifeng; Li, Yong; Chen, Jialong Quartz glass has wide applications in semiconductor technology, optical communication, optical instruments, inertial navigation, and other fields. Quartz glass parts are commonly machined by mechanical methods, and in general, there is a certain thickness of damage layer on the surface after processing. To improve the surface quality of quartz glass parts, this study proposes a chemical surface finishing process for the quartz glass rotary parts based on changes in wetting state. Corrosion droplet on the surface of quartz glass is used to selectively remove materials, thereby reducing surface roughness. The experimental results show that using buffered oxide etch to form corrosion droplets for surface chemical finishing can reduce the Sa value on the surface of quartz glass rotary parts from 104 nm to 74 nm after 2 min of processing with a surface velocity of 26.2 m/s. In addition, for quartz glass rotary parts with different pretreatment methods, all of the surface roughness Sa values of the workpiece are reduced, after chemical surface finishing. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310414 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310312 Influence of Microwave-Treated Waste Aramid Fibers on the Mechanical Behavior of 3D-Printed Composite Materials Patadiya, Jigar; Kandasubramanian, Balasubramanian; Naebe, Minoo; Yadav, Ramdayal; Ganesan, Vansala; Joseph, Tharika Industrial surface modification techniques are commonly employed to enhance the adhesion between polymer matrices and aramid fibers (AFs) in composite materials. However, these techniques are often associated with high costs, operational complexity, and environmental drawbacks. This study presents the development of a cost-effective, eco-friendly, and efficient microwave-assisted surface treatment for aramid fibers. The technique utilizes microwave irradiation to increase surface roughness, disrupt crystalline bonding, and introduce oxygen-containing functional groups, thereby enhancing surface energy and fiber reactivity. Moreover, the microwave-induced electromagnetic fields promote microstructural changes within the aramid fabric, strengthening intermolecular interactions and improving interfibrillar bond integrity. The process was optimized using the Taguchi design of experiments (DOE) methodology, ensuring that the mechanical properties of the fibers remained intact while achieving precise adhesion control with thermoplastic matrices. The study also incorporates advanced additive manufacturing techniques—fused deposition modeling (FDM) and direct ink writing (DIW)—to fabricate aramid fiber-reinforced sandwich composites. These techniques were selected to enhance the composite's mechanical strength, interfacial adhesion, and resistance to environmental degradation. Experimental results demonstrate a significant enhancement in surface wettability, with the water contact angle reduced from 120 deg to 11.2 deg. Additionally, interlaminar shear strength increased substantially from 35 MPa to 96 MPa. Tensile tests revealed a modulus of 516 MPa, and Izod impact tests showed an impact resistance of 599 J/m, validating the effectiveness of the microwave-assisted surface treatment in significantly improving the performance metrics of aramid fiber-reinforced composites. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310312 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310305 Investigation of Virtual Impactor Design Parameters in Aerosol Jet Printing Using Computational Fluid Dynamics Sareen, Akashita; Hill, Curtis W.; Salary, Roozbeh “Ross” Aerosol jet printing (AJP) is a direct-write additive manufacturing technique used to fabricate electronics, such as sensors, capacitors, and optoelectronic devices. It has gained significant attention in being able to utilize aerodynamic principles to deposit conductive inks (such as silver nanoparticle-based inks) onto rigid and flexible substrates. The aerosol jet printing system consists of three main components to execute the printing process: (i) the pneumatic atomizer, (ii) the virtual impactor, and (iii) the deposition head. The virtual impactor (VI) lies between the pneumatic atomizer and the deposition head, accepting the accelerated flow of differently sized aerosol particles from the pneumatic atomizer while acting as an “aerodynamic separator.” With the challenges associated with efficiency as well as resulting quality of the AJP process, the virtual impactor presents a unique opportunity to gain a deeper understanding of the component itself, aerosol particle flow behavior, and how it contributes to overall printing inefficiencies, poor repeatability, and resulting print quality. Broadly, this effort enables the expedited adoption of AJP in the electronics industry and beyond large scales. The challenges mentioned are addressed in this work by conducting a computational fluid dynamics (CFD) study of the virtual impactor to visualize fluid transportation and deposition under specific conditions. The objective of this study is to observe and characterize a single-phase, compressible, turbulent flow through the virtual impactor in AJP. The virtual impactor geometry is modeled in the ANSYS FLUENT environment based on the design by Optomec. The virtual impactor is assembled using a housing, collector, jet, stem, O-rings, and a retaining nut. Subsequently, a mesh structure is generated to discretize the flow domain. In addition, material properties, boundary conditions, and the relevant governing equations (based on the Navier–Stokes equations) are utilized to, ultimately, generate an accurate steady-state solution. The fluid flow is examined with respect to mass flow rates set at boundary conditions. The aerosol particles' interactions with the inner walls of the virtual impactor are observed. Particularly, an insight into the characteristics of aerosol particles entering the virtual impactor and their transition into a smoother flow before entering the deposition head is gained. Furthermore, the analysis provides an opportunity to observe fluid flow separation based on the design of the virtual impactor, one of its main functions in the AJP process. This exposes probable causes for inaccurate print quality, flow blockages, inconsistent outputs, process instability, and other material transport inefficiencies. Overall, this research work lays the foundation for improvements in the knowledge and performance of aerosol jet printing's virtual impactor toward optimal fabrication of printed electronics. Wed, 01 Jan 2025 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310305 2025-01-01T00:00:00Z http://yetl.yabesh.ir/yetl1/handle/yetl/4310297 A Review on Recent Progress of Biodegradable Magnetic Microrobots for Targeted Therapeutic Delivery: Materials, Structure Designs, and Fabrication Methods Cao, Yang; Michel, Karen Nunez; Alimardani, Farzam; Wang, Yi Targeted therapeutic delivery employs various technologies to enable precise delivery of therapeutic agents (drugs or cells) to specific areas within the human body. Compared with traditional drug administration routes, targeted therapeutic delivery has higher efficacy and reduced medication dosage and side effects. Soft microscale robotics have demonstrated great potential to precisely deliver drugs to the targeted region for performing designated therapeutic tasks. Microrobots can be actuated by various stimuli, such as heat, light, chemicals, acoustic waves, electric fields, and magnetic fields. Magnetic manipulation is well-suited for biomedical applications, as magnetic fields can safely permeate through organisms in a wide range of frequencies and amplitudes. Therefore, magnetic actuation is one of the most investigated and promising approaches for driving microrobots for targeted therapeutic delivery applications. To realize safe and minimally invasive therapies, biocompatibility and biodegradability are essential for these microrobots, which eliminate any post-treatment endoscopic or surgical removals. In this review, recent research efforts in the area of biodegradable magnetic microrobots used for targeted therapeutic delivery are summarized in terms of their materials, structure designs, and fabrication methods. In the end, remaining challenges and future prospects are discussed. Mon, 01 Jan 2024 00:00:00 GMT http://yetl.yabesh.ir/yetl1/handle/yetl/4310297 2024-01-01T00:00:00Z