The performance of a CO2 laser has been improved by coating the inside wall of the discharge tube with a discontinuous gold film. In the presence of the discharge, the gold acts as an ambient temperature catalyst to reform decomposed CO2.... more
The performance of a CO2 laser has been improved by coating the inside wall of the discharge tube with a discontinuous gold film. In the presence of the discharge, the gold acts as an ambient temperature catalyst to reform decomposed CO2. The gold coated laser delivered 122 W/m for both sealed-off and flowing operation. CO2 decomposition levels are presented as a function of input power, gas pressure, and temperature. Atomic oxygen, generated by the discharge, appears to be required for gold to exhibit any detectable catalytic activity.
In this study, we investigate the effects of CO2 laser polishing on microscopic structures fabricated by femtosecond laser assisted carving (FLAC). FLAC is the peripheral laser irradiation of 2.5D structures suitable for low repetition... more
In this study, we investigate the effects of CO2 laser polishing on microscopic structures fabricated by femtosecond laser assisted carving (FLAC). FLAC is the peripheral laser irradiation of 2.5D structures suitable for low repetition rate lasers and is first used to define the microwell structures in fused silica followed by chemical etching. Subsequently, the bottom surface of patterned microwells is irradiated with a pulsed CO2 laser. The surfaces were characterized using an atomic force microscope (AFM) and scanning electron microscope (SEM) in terms of roughness and high quality optical imaging before and after the CO2 laser treatment. The AFM measurements show that the surface roughness improves more than threefold after CO2 laser polishing, which promises good channel quality for applications that require optical imaging. In order to demonstrate the ability of this method to produce low surface roughness systems, we have fabricated a microfluidic channel. The channel is filled with polystyrene bead-laden fluid and imaged with transmission mode microscopy. The high quality optical images prove CO2 laser processing as a practical method to reduce the surface roughness of microfluidic channels fabricated by femtosecond laser irradiation. We further compared the traditional and laser-based glass micromachining approaches, which includes FLAC followed by the CO2 polishing technique.
We have many customer need machine for processing coconut. But generally, they don’t know which model machine is suitable for their work. If you are in this industry, from this artical, you can know how to choose one set right machine for... more
We have many customer need machine for processing coconut. But generally, they don’t know which model machine is suitable for their work. If you are in this industry, from this artical, you can know how to choose one set right machine for your coconut.
Glass woven fabric is produced by interlacing fine fibres of glass (commonly known as fibreglass). A single-strand of these fibres has greater specific tensile strength than that of a steel wire of the same diameter. Due to its... more
Glass woven fabric is produced by interlacing fine fibres of glass (commonly known as fibreglass). A single-strand of these fibres has greater specific tensile strength than that of a steel wire of the same diameter. Due to its lightweight and strong tensile properties, glass woven fabric offers numerous benefits in many industries. Since it is impractical to use conventional methods for cutting the glass woven fabric, a CO2 laser seems to be an appropriate tool for such application. In the present study, an investigation is carried out to characterise the effects of laser cutting parameters, namely, laser power, cutting speed, compressed air pressure and stand-off distance, on the kerf width of the cut. Taguchi design of experiment is employed to account for the interaction between various process parameters, and their significance is further evaluated using ANOVA technique. This study indicates that laser power has dominant effect on the kerf width.
We describe 4 pediatric patients (age 6-11 years) who underwent transcanal endoscopic ear surgery (TEES) with the assistance of a flexible fiber CO2 laser over a period of 6 months. Three of these individuals suffered from densely... more
We describe 4 pediatric patients (age 6-11 years) who underwent transcanal endoscopic ear surgery (TEES) with the assistance of a flexible fiber CO2 laser over a period of 6 months. Three of these individuals suffered from densely adherent cholesteatoma, where the laser permitted one-handed dissection while preserving endoscopic visualization by limiting bleeding. In the fourth patient, TEES ossiculoplasty was performed for a congenital stapes bar, with subsequent hearing improvement. Advantages and disadvantages of the flexible fiber CO2 laser in the setting of TEES are discussed. Use of the flexible fiber CO2 laser was found to expand the TEES toolkit.
Over the past decade flexible and wearable micro-electronic devices and systems are gaining significant importance. Since portable power source is an essential need of such wearable devices, currently there is considerable research... more
Over the past decade flexible and wearable micro-electronic devices and systems are gaining significant importance. Since portable power source is an essential need of such wearable devices, currently there is considerable research emphasis on the development of planar interdigitated micro energy storage devices by employing diverse precursor materials to obtain functional materials (functional carbon, oxides etc.) with the desirable set of properties. Herein we report for the first time the use of metal organic framework (MOF), Zeolitic imidazolate framework (ZIF-67), for high wavelength photothermal laser direct writing of metal-decorated and heteroatom-doped, porous few layer graphene electrodes for micro-supercapacitor application. We argue that the specific attributes of MOF as a precursor and the high wavelength laser writing approach (which creates extremely high localized and transient temperature (>2500°C) due to strong absorption by lattice vibrations) are together responsible for the peculiar interesting properties of the carbon material thus synthesized, thereby rendering extremely high cycling stability to the corresponding micro-supercapacitor device. Our device exhibits near 100% retention after 200,000 cycles and stability under 150° bending.
A report is presented on the fabrication of all solid-state interdigitated flexible microsupercapacitor using ultrafast and highly scalable laser scribing technique, using highly mesoporous carbon synthesized from biomass (mushroom) with... more
A report is presented on the fabrication of all solid-state interdigitated flexible microsupercapacitor using ultrafast and highly scalable laser scribing technique, using highly mesoporous carbon synthesized from biomass (mushroom) with hydrothermal preprocessing. The specific protocol used for carbon synthesis renders some unique property features to the material (surface area of 2604 m² g−1 with hierarchical pore size distribution) in the context of supercapacitor electrode application. A polyvinyl alcohol (PVA)-H2SO4 gel electrolyte is used for electrochemical measurements. The microsupercapacitor shows high cyclic stability up to 15000 cycles. Moreover it shows nearly 90% stability after 1000 bending cycles at 60° angle. It also retains its performance even under 120° bending condition. This work represents a facile and fast technique for microscaled device fabrication that can be easily commercialized. Moreover, the mushroom-derived carbon used to make the electrodes holds great promise in context of the stability and flexibility of flexible supercapacitors.
In this work we demonstrate a facile approach to the fabrication of all solid state flexible interdigitated micro pseudoca-pacitor device using pre-synthesized CuCo 2 O 4 (CCO) ternary metal oxide as the electrode material. The... more
In this work we demonstrate a facile approach to the fabrication of all solid state flexible interdigitated micro pseudoca-pacitor device using pre-synthesized CuCo 2 O 4 (CCO) ternary metal oxide as the electrode material. The hydrothermally synthesized CCO exhibits a peculiar 3D interconnected aligned porous nanowall type morphology which is highly desirable for storage as well as charge transfer. The device is fabricated using CO 2 laser scribing technique and the PVA-H 3 PO 4 gel electro-lyte is used as the electrolyte. The as-synthesized CCO as well as its blend with 10 wt.% CNT are examined for the electro-chemical performance. CNT blending is shown to reduce the charge transfer resistance dramatically, thereby enhancing the pseudo capacitance. The areal capacitance of 2.29 mF cm À2 is obtained from the solid state device. Moreover, the CCO-CNT electrode also shows a high stability upto 9000 cycles without a sign of further decay. Importantly, the devices also retain over 65 % of their initial capacitance after 1000 large angle (60 8) bending cycles and 93 % of the initial capacitance under 1208 bending condition, thanks to the mechanical flexibility afforded by CNTs without disrupting conducting paths.
The present study focuses the effect of four input controllable laser cutting variables on the hole taper and hole circularity in laser trepan drilling of polymeric materials. Experiments have been conducted on acrylonitrile butadiene... more
Laser Materials Processing: A general book on the state of the art of laser technologies in 1995/1996 with an emphasis on presenting general guidelines of their application to material processing that continues today. The methodologies... more
Laser Materials Processing: A general book on the state of the art of laser technologies in 1995/1996 with an emphasis on presenting general guidelines of their application to material processing that continues today. The methodologies are still relevant today.
Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result... more
Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found at low laser power (200 W), high cutting speed (0.4 m/min) and low compressed air pressure (2.5 bar). The result matches with the objective set in the present study. Analysis of variance (ANOVA) is then carried out to ascertain the relative influence of process parameters on the cutting characteristics. It was found that the laser power has dominant effect on HAZ for all thermoplastics. (C) 2014 Elsevier Ltd. All rights reserved.
