| 1. |
- Ghai, Viney, 1989, et al.
(författare)
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Experimental investigation of single spark μ-EDM using electrodes fabricated with μ-turning process
- 2024
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Ingår i: Sadhana - Academy Proceedings in Engineering Sciences. - 0256-2499. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- Micro electrical discharge machining (μ-EDM) stands out as a widely employed non-traditional machining process with diverse applications in microfluidics, electronics, medical, aeronautics, and the automotive industry. This study is dedicated to the exploration of the single spark μ-EDM process utilizing a titanium tool electrode fabricated using a μm-turning process. Intriguingly, it is established that achieving a single spark necessitates a minimum tool diameter of 8 μm. Further, the effect of critical parameters such as voltage and capacitance on material removal rate (MRR), tool wear rate (TWR), as well as the shape and size of the resultant craters is investigated. A 7 μm tool electrode when subjected to a voltage of 100 V and a capacitance of 33 pF manifests a remarkably refined surface finish, demonstrating controlled erosion on the workpiece surface. The study also indicates that MRR and TWR vary exponentially with supplied discharge energy. This comprehensive analysis not only identifies optimal conditions for μm turning during tool fabrication but also elucidates the prerequisites for generating a controlled single spark during workpiece erosion. In essence, the findings presented here contribute valuable insights to the advancement of precision μ-EDM processes.
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| 2. |
- Ghai, Viney, 1989, et al.
(författare)
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Orientation of graphene nano sheets in magnetic fields
- 2024
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Ingår i: Progress in Materials Science. - 0079-6425. ; 143
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Forskningsöversikt (refereegranskat)abstract
- Aligning anisotropic nanoparticles using external fields is one of the major obstacles to unlocking their enormous potential for novel applications. The most famous such example is graphene, a 2D family of nanomaterials that has received enormous attention since its discovery. Using graphene to enhance mechanical, thermal, electric or gas barrier properties, imparting antibacterial properties etc., relies to a great extent on the ability to control their orientation inside a matrix material, i.e., polymers. Here we summarize the latest advances on graphene orientation using magnetic fields. The review covers the underlying physics for graphene interaction with magnetic fields, theoretical continuum mechanics framework for inducing orientation, typical magnetic field orientation setups, and a summary of latest advances in their use to enhance the performance of materials. Current trends, limitations of current alignment techniques are highlighted and major challenges in the field are identified.
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| 3. |
- Kumar, Ravinder, et al.
(författare)
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A Surface Modification Approach to Overcome Wetting Behavior of Gallium-Based Liquid Metal Droplets
- 2022
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Ingår i: IEEE Transactions on Nanotechnology. - 1941-0085 .- 1536-125X. ; 21, s. 158-162
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Tidskriftsartikel (refereegranskat)abstract
- Gallium based eutectic alloys are one of the promising substitutes for mercury. These alloys are nontoxic and environment friendly and have similar or equivalent properties as that of mercury. These alloys exhibit good electrical and thermal properties. However, these alloys form oxides when in contact with oxygen atoms. Due to this, the material surface tension changes, which renders them unsuitable for those applications where the mobility of the fluid is a valuable factor, such as in thermometers and blood pressure monitoring devices. There are few methods reported to remove the oxide layer from the surface of the gallium-based alloys, like acid and base treatment prior to use, but all these methods are not durable and long-lasting. Here in this work, we report gallium oxide coating as a simple approach to convert mercury manometer glass tube, which has glass as a substrate to a nonwetting surface against surface-oxidized gallium-based liquid metal alloys. These alloys form an oxidized layer in ambient air (O-2 >1 ppm) and show stickiness to almost all surfaces that impact the residue-free movement of the liquid metal droplets. Herein, the physical vapor deposition technique was used for gallium oxide coating on substrates such as silicon wafer and glass slide. Moreover, various characterizations were carried out to support our outcomes. This method does not require any micro/nano machining or specific nanoscale surface topology. The contact angle was measured with or without coated gallium oxide film on the glass substrate, and the static contact angle (c.a.) 137.69 degrees and with bared glass 94.30 degrees.
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| 4. |
- Ruan, Hengzhi, 1995, et al.
(författare)
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Polysaccharide-based antibacterial coating technologies
- 2023
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Ingår i: Acta Biomaterialia. - 1878-7568 .- 1742-7061. ; 168, s. 42-77
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Forskningsöversikt (refereegranskat)abstract
- To tackle antimicrobial resistance, a global threat identified by the United Nations, is a common cause of healthcare-associated infections (HAI) and is responsible for significant costs on healthcare systems, a substantial amount of research has been devoted to developing polysaccharide-based strategies that prevent bacterial attachment and biofilm formation on surfaces. Polysaccharides are essential building blocks for life and an abundant renewable resource that have attracted much attention due to their intrinsic remarkable biological potential antibacterial activities. If converted into efficient antibacterial coatings that could be applied to a broad range of surfaces and applications, polysaccharide-based coatings could have a significant potential global impact. However, the ultimate success of polysaccharide-based antibacterial materials will be determined by their potential for use in manufacturing processes that are scalable, versatile, and affordable. Therefore, in this review we focus on recent advances in polysaccharide-based antibacterial coatings from the perspective of fabrication methods. We first provide an overview of strategies for designing polysaccharide-based antimicrobial formulations and methods to assess the antibacterial properties of coatings. Recent advances on manufacturing polysaccharide-based coatings using some of the most common polysaccharides and fabrication methods are then detailed, followed by a critical comparative overview of associated challenges and opportunities for future developments. Statement of significance: Our review presents a timely perspective by being the first review in the field to focus on advances on polysaccharide-based antibacterial coatings from the perspective of fabrication methods along with an overview of strategies for designing polysaccharide-based antimicrobial formulations, methods to assess the antibacterial properties of coatings as well as a critical comparative overview of associated challenges and opportunities for future developments. Meanwhile this work is specifically targeted at an audience focused on featuring critical information and guidelines for developing polysaccharide-based coatings. Including such a complementary work in the journal could lead to further developments on polysaccharide antibacterial applications.
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