Durability of Lubricated Icephobic Coatings under Multiple Icing/Deicing Cycles

2021 ◽  
Author(s):  
Valentina Donadei ◽  
Heli Koivuluoto ◽  
Essi Sarlin ◽  
Petri Vuoristo
Keyword(s):  
Industrial Applications ◽  
Power Lines ◽  
Operational Performance ◽  
Flame Spraying ◽  
Mechanical Interlocking ◽  
Properties Of Coatings ◽  
Before And After ◽  
Outdoor Environments ◽  
One Step ◽  
Ice Adhesion

Abstract In subzero conditions, atmospheric ice naturally accretes on surfaces in outdoor environments. This accretion can compromise the operational performance of several industrial applications, such as wind turbines, power lines, aviation, and maritime transport. To effectively prevent icing problems, the development of durable icephobic coating solutions is strongly needed. Here, the durability of lubricated icephobic coatings was studied under repeated icing/deicing cycles. Lubricated coatings were produced in one-step by flame spraying with hybrid feedstock injection. The coating icephobicity was investigated by accreting ice from supercooled microdroplets using an icing wind tunnel. The ice adhesion strength was evaluated by a centrifugal ice adhesion tester. The icing performance was investigated over four icing/deicing cycles. Surface properties of coatings, such as morphology, topography, chemical composition and wettability, were analyzed before and after the cycles. The results showed an increase in ice adhesion over the cycles, while a stable icephobic behaviour was retained for one selected coating. Moreover, consecutive ice detachment caused a surface roughness increase. This promotes the formation of mechanical interlocking with ice, thus justifying the increased ice adhesion. Finally, the coating hydrophobicity mainly decreased as a consequence of the damaged surface topography. In summary, lubricated coatings retained a good icephobic level after the cycles, thus demonstrating their potential for icephobic applications.

scholarly journals Single Step 2-Port Device De-Embedding Algorithm for Fixture-DUT-Fixture Network Assembly

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1275
Author(s):  
Simone Scafati ◽  
Enza Pellegrino ◽  
Francesco de Paulis ◽  
Carlo Olivieri ◽  
James Drewniak ◽  
...  
Keyword(s):  
Standard Technique ◽  
Single Step ◽  
Scattering Parameters ◽  
Linear Set ◽  
S Parameter ◽  
Parameter Conversion ◽  
Before And After ◽  
One Step ◽  
Typical Measurement

The de-embedding of measurement fixtures is relevant for an accurate experimental characterization of radio frequency and digital electronic devices. The standard technique consists in removing the effects of the measurement fixtures by the calculation of the transfer scattering parameters (T-parameters) from the available measured (or simulated) global scattering parameters (S-parameters). The standard de-embedding is achieved by a multiple steps process, involving the S-to-T and subsequent T-to-S parameter conversion. In a typical measurement setup, two fixtures are usually placed before and after the device under test (DUT) allowing the connection of the device to the calibrated vector network analyzer coaxial ports. An alternative method is proposed in this paper: it is based on the newly developed multi-network cascading algorithm. The matrices involved in the fixture-DUT-fixture cascading gives rise to a non-linear set of equations that is in one step analytically solved in closed form, obtaining a unique solution. The method is shown to be effective and at least as accurate as the standard multi-step de-embedding one.

Micro-Ribbons and Micro-Wires Silica Synthesis Using Bottom-Top Technique

2020 ◽  
Vol 1008 ◽  
pp. 33-38
Author(s):  
Marwa Nabil ◽  
Hussien A. Motaweh
Keyword(s):  
Selection Process ◽  
Chemical Properties ◽  
Industrial Applications ◽  
Preparation Process ◽  
Pure Silica ◽  
One Step ◽  
Materials Used ◽  
Sonication Technique ◽  
Silica Synthesis ◽  
Physical And Chemical

Silica is one of the most important materials used in many industries. The basic factor on which the selection process depends is the structural form, which is dependent on the various physical and chemical properties. One of the common methods in preparing pure silica is that it needs more than one stage to ensure the preparation process completion. The goal of this research is studying the nucleation technique (Bottom-top) for micro-wires and micro-ribbons silica synthesis. The silica nanoand microstructures are prepared using a duality (one step); a combination of alkali chemical etching process {potassium hydroxide (3 wt %) and n-propanol (30 Vol %)} and the ultra-sonication technique. In addition, the used materials in the preparation process are environmentally friendly materials that produce no harmful residues. The powder product is characterized using XRD, FTIR, Raman spectrum and SEM for determining the shape of architectures. The most significant factor of the nucleation mechanism is the sonication time of silica powder production during the dual technique. The product stages are as follows; silica nanoparticles (21-38 nm), nanoclusters silica (46 – 67 nm), micro-wires silica (1.17 – 6.29 μm), and micro-ribbons silica (19.4 – 54.1 μm). It's allowing for use in environmental applications (multiple wastewater purification, multiple uses in air filters, as well as many industrial applications).

scholarly journals An Optimized Pulse-Counting Method for Compensation Vector Calculation in the Automatic Balancer

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Lifang Chen ◽  
Bo Zhou ◽  
Zhaoju Li ◽  
Yixiang Guo ◽  
Ziwen Yan
Keyword(s):  
Control System ◽  
High Speed ◽  
Industrial Applications ◽  
Counting Method ◽  
Pulse Counting ◽  
High Speed Data Acquisition ◽  
One Step ◽  
High Speed Data ◽  
The Stability ◽  
Automatic Balancing

The accuracy of the counterweight positions in an automatic balancing system deeply affects dynamic balancing. Compensation vector is synthesized by the two counterweights located in the electromagnetic dual-weight automatic balancer. Therefore, if the position of the counterweight is inaccurate, it may result in a wrong adjustment and a larger imbalance of the rotor system. In this paper, an optimized pulse counting method for compensation vector calculation in an electromagnetic dual-weight balancing system is proposed based on a programmable logic controller (PLC). A propeller automatic balancing simulation test bench is used to verify the effect of the method by obtaining the positions of the counterweights and synthesizing the compensation vector in the working mode. The error is less than 1/80 which means that it does not exceed one step in the 80-position-balancer at 1200 rpm. The proposed control system can work without computers or high-speed data acquisition equipment, which improves the stability and flexibility of the control system, facilitates the design of the automatic balancing system, and shows excellent potential for industrial applications.

Study of Damage Mechanisms in Cold-Sprayed 316L-Matrix Composite Coatings Using Novel Impact-Sliding Testing

2014 ◽  
Vol 922 ◽  
pp. 452-462 ◽  
Author(s):  
R. Maestracci ◽  
N. Fabrègue ◽  
M. Jeandin ◽  
G. Bouvard ◽  
M. Messaadi ◽  
...  
Keyword(s):  
Cold Spray ◽  
High Performance ◽  
Composite Coatings ◽  
Industrial Applications ◽  
Damage Mechanisms ◽  
Coating Composition ◽  
Before And After ◽  
Coating Microstructure ◽  
Service Conditions ◽  
Sliding Test

Cold spray is now well recognized as one of the most powerful and efficient coating process because it is cost-attractive and “green”. However, this process still shows limitations to achieve coatings for highly-demanding service conditions such as those required in certain automotive and/or aircraft applications. Beyond these limitations, cold spray is expected to compete with conventional P/M routes.The present work therefore focussed on the study of damage mechanisms in cold-sprayed AISI 316L and 316L-matrix–Cu composites coatings due to high-loading conditions. Different damage mechanisms could occur depending on the content of Cu particle addition, due to changes in the response of the microstructure to the loading. These mechanisms were studied using the newly-developed “impact-sliding” test. In this test, a steel ball impacts the coating surface at a given frequency, with a fixed angle. The influence of major testing parameters was investigated.Microstructures before and after testing were studied using optical microscopy, scanning electron microscopy (SEM), and microprobe analysis in addition to 3D optical profilometry of impacted areas. Damage mechanisms were seen to be of two types, i.e. plastic deformation and wear. These resulted in decohesion of splats, formation of wear debris and formation of a layer with a tribologically-transformed structure (TTS) at the contact surface.Results showed that cold spray could be claimed to be suitable for the achievement of high-performance coatings for industrial applications provided that the coating microstructure can be controlled. This could be done using a composite approach to the coating composition.

Characterization, Modification and Rheology of Green Clay

2015 ◽  
Vol 820 ◽  
pp. 60-64
Author(s):  
Leila Verônica da Rocha-Gomes ◽  
Antônio José Santana ◽  
Camila Martini Matos ◽  
Valquíria de Fátima Justo ◽  
Maria Das Graças Silva-Valenzuela ◽  
...  
Keyword(s):  
Water Absorption ◽  
Rheological Properties ◽  
Apparent Density ◽  
Industrial Applications ◽  
Clay Sample ◽  
Oil Drilling ◽  
Smectite Clays ◽  
Swelling Capacity ◽  
Before And After ◽  
Green Clay

Smectite clays or bentonites are used in several industrial applications. The aim of this study was to describe the characterization and organophilization of a green clay sample coming from the State of Paraíba, Brazil. The clay was characterized by XRD, XRF, CEC, SEM, stereoscopic microscopy, Fann viscosity (before and after the organophilization process), swelling capacity in water and some organic solvents. Prismatic specimens were conformed by pressing, for which were conformed the mechanical sthegth after drying at 110°C and after burning at 950°C. The burned specimens were analyzed to evaluate dimensional variations, water absorption, apparent porosity and apparent density. XRD showed that the sample was constituted mainly for montmorillonite claymineral. Analysis of rheological properties of the modified clay indicates its potential to meet the specifications of the standard N-2604 of Petrobras, concerning clays used to oil drilling.

scholarly journals Brokering a settlement between eagles and industry: sustainable management of large raptors nesting on power infrastructure

2013 ◽  
Vol 23 (2) ◽  
pp. 232-246 ◽  
Author(s):  
ANDREW R. JENKINS ◽  
KOOS H. DE GOEDE ◽  
LOVELATER SEBELE ◽  
MEGAN DIAMOND
Keyword(s):  
High Risk ◽  
Sustainable Management ◽  
Management Plan ◽  
Power Lines ◽  
Breeding Populations ◽  
Large Nest ◽  
Before And After ◽  
Short Circuits ◽  
Significant Line

SummaryIn the Karoo region of South Africa, eagles nesting on high voltage power pylons are responsible for frequent short-circuits or faults, which reduce the quality of commercial power supply and escalate costs to the country’s energy supplier, Eskom. Between 2002 and 2006 we conducted annual helicopter surveys of eagle nests on 1,400 km of power line and located 139 large nest structures, making up 96 eagle territories occupied by three species: Martial EaglePolemaetus bellicosus(66 pairs), Verreaux’s EagleAquila verreauxii(13 pairs) and Tawny EagleAquila rapax(17 pairs), and detailed 357 pair-years of breeding activity, including 241 breeding attempts. Roost sites and active nests were associated with line faulting, and more so at particular pylon configurations. We developed a three-step management plan to reduce eagle-related faulting while still accommodating eagles on the power lines: (i) all (potentially) problematic nests were relocated from high-risk positions above the power conductors, to specially provided platforms placed below the conductors; (ii) perch deterrents were installed above the conductors on all nest pylons and on high-risk pylons up to 10 structures on both sides of each nest tower; and (iii) the welfare of the eagles was monitored before and after management. In this way, line faulting was reduced on actively managed lines by > 75%, with no obvious deleterious effects on the eagle population. The study revealed that: (i) power lines can support substantial breeding populations of threatened large raptors, (ii) these birds can be a source of commercially significant line faulting, and (iii) nest relocations and perch deterrents are effective in reducing faulting without negatively impacting eagle populations.

Springback Evaluation of Parts Made by Single-Point Incremental Sheet Forming

2011 ◽  
Author(s):  
Paolo Bosetti ◽  
Stefania Bruschi
Keyword(s):  
Process Parameters ◽  
Incremental Forming ◽  
Elastic Recovery ◽  
Single Point ◽  
Industrial Applications ◽  
Geometrical Parameters ◽  
Forming Process ◽  
Part Geometry ◽  
Before And After ◽  
Measuring Machine

One of the major drawbacks of single-point incremental forming process for sheet metal (SPIF) consists in the poor geometrical accuracy of formed parts. This limits the use of SPIF technology and has pushed the development of alternative incremental processes—such as the two-points incremental forming—aimed at improving the forming accuracy. However, these processes require the use of supporting dies and they therefore reduce the competitive advantage of SPIF process. The possibility to compensate for part springback, in order to have the part geometry as close as possible to the nominal one, represents one of the major challenges to make SPIF process suitable for real industrial applications. However, any possible approach in springback compensation must pass through the comprehension of the springback phenomenon. The objective of the paper is to analyze the springback of parts made by SPIF, by evaluating the influence that elastic recovery before and after the part unclamping has on the final part geometry. A SPIF experimental campaign was carried out on a truncated pyramid as case study, by varying both the part geometrical parameters (the wall angle and the height), and the process parameters (the tool step-down size and the feed rate). The material used in this study was the duplex steel DP600 provided in 0.8 mm thick sheets. After forming—but before unclamping—the part geometry was measured by means of of an electronic touch probe mounted on the machine tool-holder, in order to investigate the elastic recovery due to the successive tool laps. After unclamping, the part geometry was measured on a coordinate measuring machine. The influence of geometrical and process parameters was analyzed and the contribution of elastic recovery before and after the part unclamping was assessed.

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