Addressing the challenges in remanufacturing by laser-based material deposition techniques

2021 ◽  
Vol 144 ◽  
pp. 107404
Author(s):  
Ankit Shrivastava ◽  
Sumanta Mukherjee ◽  
Shitanshu S. Chakraborty
Keyword(s):  
Material Deposition ◽  
Deposition Techniques

scholarly journals Polymer Blends and Polymer Nanocomposites for Photovoltaic (PV) Cells and an Investigation of the Material Deposition Techniques in PV Cell Fabrication

2021 ◽  
Vol 5 (10) ◽  
pp. 263
Author(s):  
George Ntanovasilis ◽  
Ioannis Zaverdas ◽  
Tarig Ahmed ◽  
Foivos Markoulidis ◽  
Constantina Lekakou
Keyword(s):  
Bulk Heterojunction ◽  
Low Cost ◽  
High Surface ◽  
Multiwall Carbon Nanotubes ◽  
Current Collector ◽  
Transverse Orientation ◽  
Material Deposition ◽  
Polymer Photovoltaics ◽  
Pv Cell ◽  
Deposition Techniques

Polymer photovoltaics (PV) offer the advantage of low-cost, mass-produced, flexible PV films, but they generally suffer from a low-power conversion efficiency (PCE) compared to silicon. This paper studies ITO/PEDOT:PSS/bulk heterojunction/Al PV cells, where two different bulk heterojunction blends are researched: P3HT/PC61BM and PCDTBT/PC70BM. The addition of multiwall carbon nanotubes (CNT) is explored as a conductive network to accelerate the electron transport and extraction to the outer aluminium current collector while reducing the chance of charge recombinations. Several layer deposition techniques are investigated: spin coating and casting, as well as techniques that would induce transverse orientation of polymer grains, including inkjet printing, electrophoresis and the application of a transverse AC field during annealing. Transverse orientation techniques produced architectures that would facilitate charge transport without recombinations, but it is recommended to avoid such techniques for the deposition of conductive PEDOT:PSS and CNT layers as they create a high surface roughness that leads to short circuiting. The best performing PV cell is the ITO/PEDOT:PSS/PCDTBT/PC70BM/CNT/Al structure with a PCE of 11%.

Numerical Analysis of Laminar-Drag-Reducing Grooves

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
A. Mohammadi ◽  
J. M. Floryan
Keyword(s):  
Reynolds Number ◽  
Numerical Analysis ◽  
Drag Reduction ◽  
Channel Flow ◽  
Material Removal ◽  
Flow Direction ◽  
Material Deposition ◽  
Circular Segment ◽  
Laminar Channel Flow ◽  
Deposition Techniques

The performance of grooves capable of reducing shear drag in laminar channel flow driven by a pressure gradient has been analyzed numerically. Only grooves with shapes that are easy to manufacture have been considered. Four classes of grooves have been studied: triangular grooves, trapezoidal grooves, rectangular grooves, and circular-segment grooves. Two types of groove placements have been considered: grooves that are cut into the surface (they can be created using material removal techniques) and grooves that are deposited on the surface (they can be created using material deposition techniques). It has been shown that the best performance is achieved when the grooves are aligned with the flow direction and are symmetric. For each class of grooves, there exists an optimal groove spacing, which results in the largest drag reduction. The largest drag reduction results from the use of trapezoidal grooves and the smallest results from the use of triangular grooves for the range of parameters considered in this work. Placing the same grooves on both walls increases the drag reduction by up to four times when comparing with grooves on one wall only. The predictions remain valid for any Reynolds number as long as the flow remains laminar.

Microstructures of SiC and Si3N4 with fibrous inclusions

1986 ◽  
Vol 44 ◽  
pp. 492-493
Author(s):  
N. J. Tighe ◽  
J. Sun ◽  
R.-M. Hu
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Crack Deflection ◽  
Fiber Bundles ◽  
High Temperature Strength ◽  
Graphite Fiber ◽  
Triple Junctions ◽  
Transmission Electron ◽  
Compact Graphite ◽  
Deposition Techniques

Particles of BN,and C are added in amounts of 1 to 40% to SiC and Si3N4 ceramics in order to improve their mechanical properties. The ceramics are then processed by sintering, hot-pressing and chemical vapor deposition techniques to produce dense products. Crack deflection at the particles can increase toughness. However the high temperature strength and toughness are determined byphase interactions in the environmental conditions used for testing. Examination of the ceramics by transmission electron microscopy has shown that the carbon and boron nitride particles have a fibrous texture. In the sintered aSiC ceramic the carbon appears as graphite fiber bundles in the triple junctions and as compact graphite particles within some grains. Examples of these inclusions are shown in Fig. 1A and B.

Ultra high resolution SEM at high voltage images individual fab fragments applied as molecular label to cell surface receptors

1989 ◽  
Vol 47 ◽  
pp. 70-71
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Metal Coating ◽  
Beam Diameter ◽  
Surface Receptors ◽  
Surface Mobility ◽  
Metal Atoms ◽  
Shadowing Effect ◽  
Imaging Mode ◽  
Deposition Techniques

Topographic ultra high resolution can now routinely be established on bulk samples in cold field emission scanning electron microscopy with a second generation of microscopes (FSEM) designed to provide 0.5 nm probe diameters. If such small probes are used for high magnification imaging, topographic contrast is so high that remarkably fine details can be imaged on 2DMSO/osmium-impregnated specimens at ribosome surfaces even without a metal coating. On TCH/osmium-impregnated specimens topographic resolution can be increased further if the SE-I imaging mode is applied. This requires that beam diameter and metal coating thickness be made smaller than the SE range of ~1 nm and background signal contributions be reduced. Subnanometer small probes can be obtained (only) at high accelerating voltages. Subnanometer thin continuous metal films can be produced under the following conditions: self-shadowing effect between metal atoms must be reduced through appropriate deposition techniques and surface mobility of metal atoms must be diminished through high energy sputtering and/or specimen cooling.

Advances in Stem Instrumentation for Biology

1990 ◽  
Vol 48 (1) ◽  
pp. 362-363
Author(s):  
J. S. Wall
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Carbon Films ◽  
Specimen Preparation ◽  
Material Deposition ◽  
Active User ◽  
Percent Improvement ◽  
Scanning Transmission ◽  
The Moment ◽  
Film Substrate ◽  
High Level

The forte of the Scanning transmission Electron Microscope (STEM) is high resolution imaging with high contrast on thin specimens, as demonstrated by visualization of single heavy atoms. of equal importance for biology is the efficient utilization of all available signals, permitting low dose imaging of unstained single molecules such as DNA.Our work at Brookhaven has concentrated on: 1) design and construction of instruments optimized for a narrow range of biological applications and 2) use of such instruments in a very active user/collaborator program. Therefore our program is highly interactive with a strong emphasis on producing results which are interpretable with a high level of confidence.The major challenge we face at the moment is specimen preparation. The resolution of the STEM is better than 2.5 A, but measurements of resolution vs. dose level off at a resolution of 20 A at a dose of 10 el/A2 on a well-behaved biological specimen such as TMV (tobacco mosaic virus). To track down this problem we are examining all aspects of specimen preparation: purification of biological material, deposition on the thin film substrate, washing, fast freezing and freeze drying. As we attempt to improve our equipment/technique, we use image analysis of TMV internal controls included in all STEM samples as a monitor sensitive enough to detect even a few percent improvement. For delicate specimens, carbon films can be very harsh-leading to disruption of the sample. Therefore we are developing conducting polymer films as alternative substrates, as described elsewhere in these Proceedings. For specimen preparation studies, we have identified (from our user/collaborator program ) a variety of “canary” specimens, each uniquely sensitive to one particular aspect of sample preparation, so we can attempt to separate the variables involved.

Particle velocity measurement in powder gas jets of coaxial powder nozzles for laser material deposition

2021 ◽  
Vol 33 (1) ◽  
pp. 012019
Author(s):  
Jonathan Schaible ◽  
Luis Andrea Hau ◽  
David Weber ◽  
Thomas Schopphoven ◽  
Constantin Häfner ◽  
...  
Keyword(s):  
Particle Velocity ◽  
Velocity Measurement ◽  
Laser Material ◽  
Gas Jets ◽  
Material Deposition ◽  
Particle Velocity Measurement

Thermal Analysis for a Multiple Welding Passes With Material Deposition

2019 ◽  
Author(s):  
Douglas Silva Marques Serrati ◽  
Tarcila Rocha ◽  
Douglas Araujo
Keyword(s):  
Thermal Analysis ◽  
Material Deposition

Using Statistical Methods to Optimize Patterning Parameters for Tungsten Deposition

2007 ◽  
Author(s):  
Michael DiBattista ◽  
Kimball Skinner ◽  
Rick Kneedler ◽  
Leonid Vasilvey ◽  
Lukas Drybcak ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Statistical Methods ◽  
Deposition Rates ◽  
Low Resistivity ◽  
Material Deposition ◽  
Deposition Parameters ◽  
Beam Parameters

Abstract Circuit edit and failure analysis require tungsten deposition parameters to accomplish different goals. Circuit edit applications desire low resistivity values for rewiring, while failure analysis requires high deposition rates for capping layers. Tungsten deposition can be a well controlled process for a variety of beam parameters. For circuit edit, tungsten resistivity approaching below 150 µohm-cm and 50 μm3/nC is predicted. Material deposition rates of 80 μm3/nC can be achieved with reasonable pattern accuracy using defocus as a parameter.

scholarly journals Atmospheric Pressure Plasma Deposition of TiO2: A Review

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2931
Author(s):  
Soumya Banerjee ◽  
Ek Adhikari ◽  
Pitambar Sapkota ◽  
Amal Sebastian ◽  
Sylwia Ptasinska
Keyword(s):  
Atmospheric Pressure ◽  
Gas Flow ◽  
Plasma Deposition ◽  
Atmospheric Pressure Plasma ◽  
Cost Savings ◽  
Historical Background ◽  
Pressure Plasma ◽  
Wide Range ◽  
The Status ◽  
Deposition Techniques

Atmospheric pressure plasma (APP) deposition techniques are useful today because of their simplicity and their time and cost savings, particularly for growth of oxide films. Among the oxide materials, titanium dioxide (TiO2) has a wide range of applications in electronics, solar cells, and photocatalysis, which has made it an extremely popular research topic for decades. Here, we provide an overview of non-thermal APP deposition techniques for TiO2 thin film, some historical background, and some very recent findings and developments. First, we define non-thermal plasma, and then we describe the advantages of APP deposition. In addition, we explain the importance of TiO2 and then describe briefly the three deposition techniques used to date. We also compare the structural, electronic, and optical properties of TiO2 films deposited by different APP methods. Lastly, we examine the status of current research related to the effects of such deposition parameters as plasma power, feed gas, bias voltage, gas flow rate, and substrate temperature on the deposition rate, crystal phase, and other film properties. The examples given cover the most common APP deposition techniques for TiO2 growth to understand their advantages for specific applications. In addition, we discuss the important challenges that APP deposition is facing in this rapidly growing field.

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