scholarly journals Chemical vapor treatment to improve surface finish of 3D printed polylactic acid (PLA) parts realized by fused filament fabrication

2021 ◽  
Author(s):  
Fulvio Lavecchia ◽  
Maria Grazia Guerra ◽  
Luigi Maria Galantucci
Keyword(s):  
Polylactic Acid ◽  
Surface Finish ◽  
Chemical Treatment ◽  
Low Cost ◽  
High Surface ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Fused Filament Fabrication ◽  
Before And After ◽  
Roughness Analysis

AbstractFused filament fabrication (FFF) is one of the most extensively used 3D printing process for its several advantages and the possibility to obtain complex geometries. Different materials can be processed and polylactic acid (PLA), a thermoplastic biodegradable cost-effective material, is widely used for consumer FFF. Typically, PLA printed parts have high surface roughness, due to the staircase effect, the slice-to-slice construction texture and the filament deposition. In this work, authors propose a quantitative analysis of the effects of a chemical treatment based on ethyl acetate vapors, to improve the surface finish of PLA printed parts. The solvent was selected for its low toxicity, easy availability, and low cost. To validate the treatment, a 23 full factorial plan was designed and a roughness analysis before and after the chemical treatment was performed to highlight the influence of each parameter involved.

Before-and-After Empirical Bayes Evaluation of Citywide Installation of Driver Feedback Signs

2020 ◽  
Vol 2674 (4) ◽  
pp. 419-427
Author(s):  
Mingjian Wu ◽  
Karim El-Basyouny ◽  
Tae J. Kwon
Keyword(s):  
Traffic Safety ◽  
Spatial Data ◽  
Empirical Bayes ◽  
Large Scale ◽  
Low Cost ◽  
Cost Effective ◽  
Before And After ◽  
Feedback Sign ◽  
Driver Feedback ◽  
Road Segments

Speeding is a leading factor that contributes to approximately one-third of all fatal collisions. Over the past decades, various passive/active countermeasures have been adopted to improve drivers’ compliance to posted speed limits to improve traffic safety. The driver feedback sign (DFS) is considered a low-cost innovative intervention that is being widely used, in growing numbers, in urban cities to provide positive guidance for motorists. Despite their documented effectiveness in reducing speeds, limited literature exists on their impact on reducing collisions. This study addresses this gap by designing a before-and-after study using the empirical Bayes method for a large sample of urban road segments. Safety performance functions and yearly calibration factors are developed to quantify the sole effectiveness of DFS using large-scale spatial data and a set of reference road segments within the city of Edmonton, Alberta, Canada. Likewise, the study followed a detailed economic analysis based on three collision-costing criteria to investigate if DFS was indeed a cost-effective intervention. The results showed significant collision reductions that ranged from 32.5% to 44.9%, with the highest reductions observed for severe speed-related collisions. The results further attested that the benefit–cost ratios, combining severe and property-damage-only collisions, ranged from 8.2 to 20.2 indicating that DFS can be an extremely economical countermeasure. The findings from this study can provide transportation agencies in need of implementing cost-efficient countermeasures with a tool they need to design a long-term strategic deployment plan to ensure the safety of traveling public.

scholarly journals III–V Nanowires: Synthesis, Property Manipulations, and Device Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ming Fang ◽  
Ning Han ◽  
Fengyun Wang ◽  
Zai-xing Yang ◽  
SenPo Yip ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Cost Effective ◽  
Research Field ◽  
Synthesis Methods ◽  
Comprehensive Overview ◽  
Device Applications ◽  
Property Control

III–V semiconductor nanowire (NW) materials possess a combination of fascinating properties, including their tunable direct bandgap, high carrier mobility, excellent mechanical flexibility, and extraordinarily large surface-to-volume ratio, making them superior candidates for next generation electronics, photonics, and sensors, even possibly on flexible substrates. Understanding the synthesis, property manipulation, and device integration of these III–V NW materials is therefore crucial for their practical implementations. In this review, we present a comprehensive overview of the recent development in III–V NWs with the focus on their cost-effective synthesis, corresponding property control, and the relevant low-operating-power device applications. We will first introduce the synthesis methods and growth mechanisms of III–V NWs, emphasizing the low-cost solid-source chemical vapor deposition (SSCVD) technique, and then discuss the physical properties of III–V NWs with special attention on their dependences on several typical factors including the choice of catalysts, NW diameters, surface roughness, and surface decorations. After that, we present several different examples in the area of high-performance photovoltaics and low-power electronic circuit prototypes to further demonstrate the potential applications of these NW materials. Towards the end, we also make some remarks on the progress made and challenges remaining in the III–V NW research field.

scholarly journals Modeling the Producibility of 3D Printing in Polylactic Acid Using Artificial Neural Networks and Fused Filament Fabrication

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3219
Author(s):  
Mohammad Saleh Meiabadi ◽  
Mahmoud Moradi ◽  
Mojtaba Karamimoghadam ◽  
Sina Ardabili ◽  
Mahdi Bodaghi ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Production Cost ◽  
Cost Effective ◽  
Fused Filament Fabrication ◽  
3D Printers ◽  
Artificial Neural ◽  
End Use ◽  
Artificial Neural Network Ann ◽  
Part Thickness

Polylactic acid (PLA) is a highly applicable material that is used in 3D printers due to some significant features such as its deformation property and affordable cost. For improvement of the end-use quality, it is of significant importance to enhance the quality of fused filament fabrication (FFF)-printed objects in PLA. The purpose of this investigation was to boost toughness and to reduce the production cost of the FFF-printed tensile test samples with the desired part thickness. To remove the need for numerous and idle printing samples, the response surface method (RSM) was used. Statistical analysis was performed to deal with this concern by considering extruder temperature (ET), infill percentage (IP), and layer thickness (LT) as controlled factors. The artificial intelligence method of artificial neural network (ANN) and ANN-genetic algorithm (ANN-GA) were further developed to estimate the toughness, part thickness, and production-cost-dependent variables. Results were evaluated by correlation coefficient and RMSE values. According to the modeling results, ANN-GA as a hybrid machine learning (ML) technique could enhance the accuracy of modeling by about 7.5, 11.5, and 4.5% for toughness, part thickness, and production cost, respectively, in comparison with those for the single ANN method. On the other hand, the optimization results confirm that the optimized specimen is cost-effective and able to comparatively undergo deformation, which enables the usability of printed PLA objects.

Reliability of Passive UHF RFID Copper Tags on Plywood Substrate in High Humidity Conditions

2016 ◽  
Vol 2016 (NOR) ◽  
pp. 12-16 ◽  
Author(s):  
Erja Sipilä ◽  
Johanna Virkki ◽  
Lauri Sydänheimo ◽  
Leena Ukkonen
Keyword(s):  
Moisture Absorption ◽  
Low Cost ◽  
Cost Effective ◽  
High Volume ◽  
High Humidity ◽  
Uhf Rfid ◽  
Passive Uhf Rfid ◽  
Before And After ◽  
Moist Environment ◽  
Read Range

The growth of the wireless world, especially the increasing popularity of the Internet of Things, has created a need for cost-effective and environmentally friendly electronics. Great potential lies especially in versatile applications of passive UHF RFID components. However, the reliability of these components is a major issue to be addressed. This paper presents a preliminary reliability study of glue-coated and non-coated brush-painted copper tags on a plywood substrate in high humidity conditions. The passive UHF RFID components presented in this paper are fabricated using brush-painting and photonic sintering of cost-effective copper oxide ink directly on a plywood substrate. The performance of the glue-coated and non-coated tags is evaluated through wireless tag measurements before and after high humidity testing. The measurement results show that the copper tags on plywood substrate initially achieve peak read ranges of 7–8 meters and the applied coating does not affect to the read range. Moisture does not prevent the coated tags from working in a tolerable way, although the tag performance slightly temporarily decreases due to the moisture absorption. However, when the moisture exposure is long, the performance degradation comes irreversible. The absorbed moisture decreases the read range of the non-coated tags and the performance does not return back to normal after drying. Hence, the coating improves the reliability of the tags in a moist environment compared to the non-coated tags. Based on our results, the plywood material and the used manufacturing methods are very potential for low-cost, high-volume green electronics manufacturing.

Advanced Substrate Applied Fluxing Underfill for Bonding of Fine Pitch Solder Capped Cu Pillars to Oxidized Cu Substrates

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000924-000943
Author(s):  
Russell Stapleton ◽  
Jim Greig
Keyword(s):  
Cross Sections ◽  
Flip Chip ◽  
Low Cost ◽  
Cost Effective ◽  
Filler Loading ◽  
Thermal Compression ◽  
Transparent Substrate ◽  
Fine Pitch ◽  
Before And After ◽  
Cu Substrates

Underfill solutions for fine pitch flip chip assemblies is an active area of development. Non-conductive films (NCF) and pastes (NCP) have shown great potential in bridging the gap between no-flow and capillary underfills for improving the reliability of fine pitched devices. But NCFs and NCPs require costly passivated pad finishes (e.g. Au, Sn, Ni, OSP) or careful substrate handling for proper solder joint formation. In this paper, we will describe a new class of underfill material that benefits from the growing trend of using thermal compression bonding as a cost effective alternative to mass reflow based underfilling processes (e.g. capillary and no-flow). This material is a fluxing NCP that is useful for a wide variety of fine pitch substrates, including low cost Cu. The material we will demonstrate contains many advanced features: high filler loading, strong flux activity, long work life, off-tool pre-dispense, low stress, high Tg, high modulus and rapid cure. The all-in-one underfill demonstrated in this paper is applied by using a screen printing process, where the material is applied to all of the chip sites in one step achieving excellent application efficiency and wetting/conformity to the substrate. The substrate is glass, containing a 4x4 array of die sites. Each of the die sites are 5x5mm in size with a full area array of 2501 Cu pads (50um pads on 100um pitch) that are pre-oxidized for 1h at 175C in air prior to printing (to simulate a dehydration bake). This transparent substrate was chosen to show the robust nature of the underfill for fluxing, stability and void-free placement/cure. Images of the substrate, before and after chip bonding will be given, along with cross sections. Details of the material properties will also be discussed.

Kinetic, isotherm and thermodynamic aspects of Cu2+ biosorption onto Rosa damascena leaf as a low-cost biosorbent: Optimization of process variables by Response Surface Methodology

2021 ◽  
Author(s):  
Mustafa A. Fawzy ◽  
Hatim M. Al-Yasi ◽  
Tarek M. Galal ◽  
Reham Z. Hamza ◽  
Esmat F. Ali ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Aqueous Solutions ◽  
Response Surface ◽  
Structural Characteristics ◽  
Low Cost ◽  
High Surface ◽  
Isotherm Models ◽  
Rosa Damascena ◽  
Before And After ◽  
Leaf Powder

Abstract In this study, the Rosa damascena leaf powder was evaluated as a biosorbent for copper removal from aqueous solutions. Optimized conditions of 4.0 g/L biosorbent dosage, pH of 5.5 and initial copper concentration of 55 mg/L obtained by Response Surface Methodology were employed for Cu2+ biosorption by R. damascena leaves and up to 88.7 % Cu2+ was removed. The biosorption data were well fitted to the pseudo-second order and Elovich kinetic models. The Langmuir and Dubinin-Radushkevich isotherm models were also best fit the experimental data showing monolayer isotherm with qmax value of 25.13 mg/g obtained at optimum conditions. Thermodynamic parameters showed the spontaneity, feasibility and exothermic nature of adsorption. Scanning electron microscopy, Energy-Dispersive X-Ray, and Fourier transform infrared spectroscopy were used to characterize the biosorbent before and after Cu2+ biosorption, revealing outstanding structural characteristics and high surface functional groups availability. In addition, immobilized R. damascena leaves adsorbed 90.7 % of copper from aqueous solution, which is greater than free biosorbent (85.3 %). It can be concluded that R. damascena might be employed as a low-cost biosorbent for removing heavy metals from aqueous solutions.

Leading Pedestrian Intervals

2017 ◽  
Vol 2620 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Anuj Sharma ◽  
Edward Smaglik ◽  
Sirisha Kothuri ◽  
Oliver Smith ◽  
Peter Koonce ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Crash Data ◽  
Trade Offs ◽  
Quantitative Metrics ◽  
Traffic Conflicts ◽  
Before And After ◽  
Economic Analyses ◽  
Benefit Cost

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPIs) to provide pedestrians with a walk signal for a few seconds before the parallel vehicular green indication. Previous before-and-after studies and simple economic analyses have indicated that LPIs are low-cost tools that can reduce vehicle–pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, municipalities have little guidance for when to implement LPIs. A marginal benefit–cost framework is developed with quantitative metrics and extends the concept of traffic conflicts and marginal safety–delay trade-offs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The method provides guidance to help quantify the probability of a conflict occurring and direction on whether to implement an LPI at a given location from macroscopic-level inputs, including number of turning movements, crash data, and geometry. A case study with sample data indicated that an LPI was cost-effective for the scenario presented.

Design and Fabrication of Microfluidics Paper-Based Devices for Contaminant Detection Using aWax Printer

2021 ◽  
Vol 2021 (16) ◽  
pp. 339-1-339-8
Author(s):  
Qiyue Liang ◽  
Min Zhao ◽  
George T. C. Chiu ◽  
Jan P. Allebach
Keyword(s):  
Image Processing ◽  
Microfluidic Device ◽  
Low Cost ◽  
Cost Effective ◽  
Back Side ◽  
Minimum Width ◽  
Before And After ◽  
Wax Printing ◽  
Multiple Devices ◽  
Processing Techniques

In this paper, we introduce an eight-channel paper-based microfluidic device that aims to detect multiple chemicals at once. The microfluidic device we propose is fabricated by wax printing on filter paper, which is trouble-free to handle, low cost, and easy to fabricate. As a hydrophobic material, wax (solid ink) defines the hydrophilic channels for testing. By using image processing techniques, we analyze the width change caused by heating of wax strokes and wax channels, which is a necessary step in the wax printing fabrications. In the same way, we test the minimum width of a channel that allows solutions to cross through and the minimum width of a barrier that is hydrophobic and blocks liquid flow. We also compare two different heating methods, the heat gun and the hot plate, by checking the wax channel width before and after heating based on our image processing pipeline. We conclude that a heat gun will be better for heating channels with relatively large widths. Using high resolution wax printing, we integrate multiple devices on a single paper, which makes this method very cost-effective. Lamination of wax-printed paper based devices is also analyzed, as leakage on the back side of paper is sometimes worth attention.

A Comprehensive Review on Magnetic Abrasive Finishing Process

2016 ◽  
Vol 18 ◽  
pp. 1-20 ◽  
Author(s):  
Mohannad Naeem Houshi
Keyword(s):  
Surface Finish ◽  
Low Cost ◽  
High Surface ◽  
Functional Requirements ◽  
Workpiece Surface ◽  
Magnetic Abrasive Finishing ◽  
Finishing Process ◽  
Abrasive Finishing ◽  
Superior Surface ◽  
Finishing Processes

In the nanotechnology era, the need for products with high quality and surfaces with free-from damage has become an urgent necessity. Many components in the precision industries such as electronics, automobile, medical, and aviation require high surface finish to meet their functional requirements, such as, reducing fluid flow resistance, friction, optical losses and increase fatigue strength. However, the scale of such surface quality cannot be achieved by traditional finishing methods. To overcome these limitations, many advanced finishing processes have been developed such as abrasive flow finishing, magnetorheological fluid finishing, magnetic float polishing, and chemical mechanical polishing and magnetic abrasive finishing. Magnetic abrasive finishing (MAF) is one of advanced finishing processes which offers superior surface finish over conventional finishing processes, because of its self-adaptability to finish of different geometric shapes, its a gentle tool which does not impact workpiece surface, its capability to polish advanced engineering materials and its low cost. This article has been focused on MAF, as well as reviewing of advanced finishing processes. The recent researches and challenges of MAF have been discussed as well.

scholarly journals Pelleting Vineyard Pruning at Low Cost with a Mobile Technology

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2477 ◽  
Author(s):  
Giuseppe Toscano ◽  
Vincenzo Alfano ◽  
Antonio Scarfone ◽  
Luigi Pari
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Point Of View ◽  
Production Costs ◽  
Direct Production ◽  
Economic Point ◽  
Before And After ◽  
Variable Distance ◽  
Intermediate Storage

The goal of this work was to test a patented pruning harvester and a mobile pelleting system specifically designed for the vineyard agripellet chain. Biomass was characterized before and after storage and after the pelleting stage. The performance, the fuel consumption, and the work quality of the harvester were assessed together with the productivity and the power consumption of the mobile pelleting system. Production costs of pellet were estimated for the whole logistic chain, considering two scenarios: Storage and pelleting directly at the farm site or at a dedicated location at variable distance from the fields. For comparison, the direct production of chips without pelleting was considered. Results indicate that harvester performance was quite good and comparable with commercial solutions; the chips produced exhibited excellent storage performance, allowing direct pelleting without forced drying; the pellet quality was good comparable with that produced from forestry biomass. From an economic point of view, in-field pelleting was the most cost-effective solution, with a good margin of profit up to 57€ t−1; on the other hand, when transport to an intermediate storage center is necessary, profit margin reduces gradually and fades off at an average 50 km distance from the fields.

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