scholarly journals Design Rule for Constructing Buckling-Free Polymeric Stencil with Microdot Apertures

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4361
Author(s):  
Minju Kim ◽  
Jinwon Lee ◽  
Junsoo Kim ◽  
Segeun Jang ◽  
Sang Moon Kim
Keyword(s):  
Aspect Ratio ◽  
Low Cost ◽  
Slenderness Ratio ◽  
External Pressure ◽  
Design Rule ◽  
Process Failure ◽  
Silicon Based ◽  
Critical Buckling Pressure ◽  
Structurally Stable ◽  
Conformal Contact

A polymeric stencil with microdot apertures made by using polydimethylsiloxane (PDMS) molds with pillar patterns has many advantages, including conformal contact, easy processability, flexibility, and low cost compared to conventional silicon-based membranes. However, due to the inherent deformability of PDMS materials in response to external pressure, it is challenging to construct structurally stable stencils with high structural fidelity. Here, we propose a design rule on the buckling pressure for constructing polymeric stencils without process failure. To investigate the critical buckling pressure (Pcr), stencils are fabricated by using different PDMS molds with aspect ratio variations (AR: 1.6, 2.0, 4.0, and 5.3). By observing the buckled morphology of apertures, the structures can be classified into two groups: low (AR 1.6 and 2.0) and high (AR 4.0 and 5.3) AR groups, and Pcr decreases as AR increases in each group. To investigate the results theoretically, the analysis based on Euler’s buckling theory and slenderness ratio is conducted, indicating that the theory is only valid for the high-AR group herein. Besides, considering the correction factor, Pcr agrees well with the experimental results.

scholarly journals Experimental Study and Development of Design Formula for Estimating the Ultimate Strength of Curved Plates

2021 ◽  
Vol 11 (5) ◽  
pp. 2379
Author(s):  
Jeong-Hyeon Kim ◽  
Doo-Hwan Park ◽  
Seul-Kee Kim ◽  
Myung-Sung Kim ◽  
Jae-Myung Lee
Keyword(s):  
Aspect Ratio ◽  
Ultimate Strength ◽  
Large Deflection ◽  
Slenderness Ratio ◽  
Compressive Load ◽  
Element Analysis ◽  
Shipbuilding Industry ◽  
Design Formula ◽  
Deflection Analysis ◽  
Collapse Behavior

The curved plate has been extensively used as a structural member in many industrial fields, especially the shipbuilding industry. The present study investigated the ultimate strength and collapse behavior of the simply supported curved plate under a longitudinal compressive load. To do this, experimental apparatuses for evaluating the buckling collapse test of the curved plates was developed. Then, a series of buckling collapse experiments was carried out by considering the flank angle, slenderness ratio, and aspect ratio of plates. To examine the fundamental buckling and collapse behavior of the curved plate, elastoplastic large deflection analysis was performed using the commercial finite element analysis program. On the basis of both the experimental and FE analysis, the effects of the flank angle, slenderness ratio, and aspect ratio on the characteristics of the buckling and collapse behavior of the curved plates are discussed. Finally, the empirical design formula for predicting the ultimate strength of curved plates was derived. The proposed empirical formula is a good indicator for estimating the behavior of the curved plate.

scholarly journals Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tero Jalkanen ◽  
Anni Määttänen ◽  
Ermei Mäkilä ◽  
Jaani Tuura ◽  
Martti Kaasalainen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Smart Cities ◽  
Low Cost ◽  
Electrical Characterization ◽  
Fabrication Process ◽  
Sensing Element ◽  
Paper Substrate ◽  
Roll To Roll ◽  
Silver Electrodes ◽  
Silicon Based

A roll-to-roll compatible fabrication process of porous silicon (pSi) based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH) was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer) was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

Materials Selection for Sandwich Pipes Under the Combined Effect of Pressure, Bending and Temperature

2007 ◽  
Author(s):  
Allan R. de Souza ◽  
Theodoro A. Netto ◽  
Ilson P. Pasqualino
Keyword(s):  
Structural Strength ◽  
Material Selection ◽  
Low Cost ◽  
Polymeric Materials ◽  
External Pressure ◽  
Core Material ◽  
Annular Layer ◽  
Oil And Natural Gas ◽  
Longitudinal Bending ◽  
Logic Approach

Recent researches point to the great potential of the sandwich pipe conception for ultra deepwater exploitation and production of oil and natural gas. Its configuration is very simple and comprises two concentric metallic pipes with a core material, polymeric or ceramic, in the annulus. The main functions of the annular layer are: to provide satisfactory thermal insulation so as to avoid the formation of wax and hydrates along the pipeline during production shutdown; to improve the overall structural strength of the system. Polypropylene and cement have been recently proposed for these applications. The reason for the choice of these materials was the low cost and the extensive availability in industry. Here a systematic material selection approach is employed in order to assess the applicability of other polymeric materials. The attributes of materials needed to meet the design specification are thoroughly studied. The list of possible materials was enlarged and the modified digital logic approach is used with the purpose to define a top group of materials for further numerical comparative study. Finite element analyses are carried out to assess the structural strength of the sandwich pipe under pure external pressure or longitudinal bending and combined external pressure and bending. Additionally, the effect of thermal gradient is included to the numerical analyses to evaluate each pre-selected material of the top group. Results indicate that other potential materials such as PEEK and polycarbonate can improve the structural performance of the sandwich pipe conception and yet meet other several design criteria.

scholarly journals Major Impediment to Highly Efficient, Stable and Low-Cost Perovskite Solar Cells

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 964 ◽  
Author(s):  
Yue Zhang ◽  
Haiming Zhang ◽  
Xiaohui Zhang ◽  
Lijuan Wei ◽  
Biao Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Carrier Mobility ◽  
High Efficiency ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Environmental Stability ◽  
Perovskite Materials ◽  
Hybrid Perovskite ◽  
Silicon Based ◽  
Major Impediment

Organic–inorganic hybrid perovskite solar cells (PSCs) have made immense progress in recent years, owing to outstanding optoelectronic properties of perovskite materials, such as high extinction coefficient, carrier mobility, and low exciton binding energy. Since the first appearance in 2009, the efficiency of PSCs has reached 23.3%. This has made them the most promising rival to silicon-based solar cells. However, there are still several issues to resolve to promote PSCs’ outdoor applications. In this review, three crucial aspects of PSCs, including high efficiency, environmental stability, and low-cost of PSCs, are described in detail. Recent in-depth studies on different aspects are also discussed for better understanding of these issues and possible solutions.

Further experiments and modeling for microscale compression molding of metals at elevated temperatures

2007 ◽  
Vol 22 (7) ◽  
pp. 1839-1848 ◽  
Author(s):  
J. Jiang ◽  
W.J. Meng ◽  
G.B. Sinclair ◽  
E. Lara-Curzio
Keyword(s):  
High Temperature ◽  
Aspect Ratio ◽  
Tensile Testing ◽  
Elevated Temperatures ◽  
Low Cost ◽  
Mold Insert ◽  
Compression Molding ◽  
Mechanics Model ◽  
Replication Technique ◽  
High Temperature Tensile

Replication of metallic high-aspect-ratio microscale structures (HARMS) by compression molding has been demonstrated recently. Molding replication of metallic HARMS can potentially lead to low-cost fabrication of a wide variety of metal-based microdevices. Understanding the mechanics of metal micromolding is critical for assessing the capabilities and limitations of this replication technique. This paper presents results of instrumented micromolding of Al. Measured molding response was rationalized with companion high-temperature tensile testing of Al using a simple mechanics model of the micromolding process. The present results suggest that resisting pressure on the mold insert during micromolding is governed primarily by the yield stress of the molded metal at the molding temperature and a frictional traction on the sides of the insert. The influence of strain rate is also considered.

scholarly journals Research progress of carbon-assisted etching of silicon nanostructures

2021 ◽  
Vol 2076 (1) ◽  
pp. 012060
Author(s):  
Xiaoyu Yang ◽  
Ling Tong ◽  
Lin Wu ◽  
Baoguo Zhang ◽  
Zhiyuan Liao ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Lithium Ion ◽  
Development Trend ◽  
Research Progress ◽  
Silicon Nanostructures ◽  
Storage Devices ◽  
Existing Problems ◽  
Energy Conversion And Storage ◽  
Silicon Based

Abstract Silicon nanostructures are attracting growing attention due to their properties and promising application prospects in solar energy conversion and storage devices, thermoelectric devices, lithium-ion batteries, and biosensing technologies. The large-scale and low-cost preparation of silicon nanostructures is critical for silicon-based advanced functional devices commercialization. In this paper, the feasibility and mechanism of silicon nanostructure fabricated by non-metallic carbon catalytic etching, as well as the currently existing problems and future development trend are reviewed.

scholarly journals Sea of Electrodes Array (SEA): Extremely Dense and High-Count Silicon-Based Electrode Array Technology for High-Resolution High-Bandwidth Interfacing with 3D Neural Structures

2021 ◽  
Author(s):  
Amin Sandoughsaz Zardini ◽  
Behnoush Rostami ◽  
Khalil Najafi ◽  
Vaughn L. Hetrick ◽  
Omar J. Ahmed
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Electrode Array ◽  
High Count ◽  
Array Technology ◽  
High Bandwidth ◽  
Length Width ◽  
Silicon Based ◽  
The Brain

AbstractIn this work, we propose a new silicon-based micro-fabrication technology to fabricate 3D high-density high-electrode-count neural micro-probe arrays scalable to thousands and even millions of individual electrodes with user-defined length, width, shape, and tip profile. This unique technology utilizes DRIE of ultra-high aspect-ratio holes in silicon and refilling them with multiple films to form thousands of individual needles with metal tips making up the “sea-of-electrodes” array (SEA). World-record density of 400 electrodes/mm2 in a 5184-needle array is achieved. The needles are ~0.5-1.2mm long, <20μm wide at the base, and <1μm at the tip. The silicon-based structure of these 3D array probes with sharp tips, makes them stiff enough and easily implantable in the brain to reach a targeted region without failing. Moreover, the high aspect ratio of these extremely fine needles reduces the tissue damage and improves the chronic stability. Functionality of the electrodes is investigated using acute in vivo recording in a rat barrel field cortex under isoflurane anesthesia.

The Effect of Strain on the Formation of Dislocations at the SiGe/Si Interface

MRS Bulletin ◽  
1996 ◽  
Vol 21 (4) ◽  
pp. 38-44 ◽  
Author(s):  
F.K. LeGoues
Keyword(s):  
Metal Oxide ◽  
High Speed ◽  
High Performance ◽  
Field Effect Transistors ◽  
Low Cost ◽  
Complementary Metal Oxide Semiconductor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Design Rule ◽  
Strained Si

Recently much interest has been devoted to Si-based heteroepitaxy, and in particular, to the SiGe/Si system. This is mostly for economical reasons: Si-based technology is much more advanced, is widely available, and is cheaper than GaAs-based technology. SiGe opens the door to the exciting (and lucrative) area of Si-based high-performance devices, although optical applications are still limited to GaAs-based technology. Strained SiGe layers form the base of heterojunction bipolar transistors (HBTs), which are currently used in commercial high-speed analogue applications. They promise to be low-cost compared to their GaAs counterparts and give comparable performance in the 2-20-GHz regime. More recently we have started to investigate the use of relaxed SiGe layers, which opens the door to a wider range of application and to the use of SiGe in complementary metal oxide semiconductor (CMOS) devices, which comprise strained Si and SiGe layers. Some recent successes include record-breaking low-temperature electron mobility in modulation-doped layers where the mobility was found to be up to 50 times better than standard Si-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Even more recently, SiGe-basedp-type MOSFETS were built with oscillation frequency of up to 50 GHz, which is a new record, in anyp-type material for the same design rule.

Quasi-static compression behavior and microstructure changes in low-cost AA6061 composites

2021 ◽  
pp. 095440622110553
Author(s):  
Hariharasakthisudhan P ◽  
Hariharasudhan T ◽  
Karthik S ◽  
Sathickbasha K ◽  
Surya Rajan B
Keyword(s):  
Aspect Ratio ◽  
Strain Hardening ◽  
Axial Strain ◽  
Low Cost ◽  
Research Work ◽  
Strain Hardening Exponent ◽  
Static Compression ◽  
Compression Behavior ◽  
Maximum Value ◽  
Quasi Static Compression

The workability study of the composites enhances the understanding of the degree of plastic deformation that can be employed on it. The current research work highlights the response of the low-cost aluminum composites reinforced with exhausted alkaline battery powders under quasi-static compression. The effect of reinforcements and aspect ratio against the strain hardening exponent and strength coefficients were investigated. The microstructural changes after quasi-static compression were studied and related to the changes in the property of the composites. The composite with 6 wt.% of reinforcement showed the least amount of porosity as 1.2%. In most of the cases, the maximum value of average strain hardening exponent with respect to axial strain was noted in the composites with 6 wt. % of reinforcement. The lowest aspect ratio of 0.5 showed the maximum workability in the composites. The average strength coefficient was found to be maximum (308.58 MPa) in the composite with 2 wt.% reinforcement. The elongated grains and slip bands were observed in the microstructure of the compressed specimens.

EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures Using a Low-Cost Automated Batch Process

1999 ◽  
Author(s):  
Fan-Gang Tseng ◽  
Gang Zhang ◽  
Uri Frodis ◽  
Adam Cohen ◽  
Florian Mansfeld ◽  
...  
Keyword(s):  
Low Temperature ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Low Cost ◽  
Batch Process ◽  
Unlimited Number ◽  
Metal Layers ◽  
Electrochemical Fabrication ◽  
Low Temperature Process

Abstract EFAB (“Electrochemical FABrication”) is a new micromachining process utilizing an innovative “Instant Masking” (IM) technique to electrochemically deposit an unlimited number of metal layers for microfabrication. Through this approach, high-aspect-ratio microstructures with arbitrary 3-D geometry can be rapidly and automatically batch-fabricated at low temperature (&lt; 60 °C) using an inexpensive desktop machine. IC-MEMS integration can also be carried out by this low temperature process.

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