Evaluation of the Durability of Slippery, Liquid-Infused Porous Surfaces in Different Aggressive Environments: Influence of the Chemical-Physical Properties of Lubricants

Liquid-repellent surfaces have been extensively investigated due to their potential application in several fields. Superhydrophobic surfaces achieve outstanding water repellence, however their limited durability in severe operational conditions hinders their large-scale application. The Slippery, Liquid-Infused Porous Surface (SLIPS) approach solves many of the durability problems shown by superhydrophobic surfaces due to the presence of an infused liquid layer. Moreover, SLIPS show enhanced repellence towards low surface tension liquids that superhydrophobic surfaces cannot repel. In this perspective, SLIPS assume significant potential for application in harsh environments; however, a systematic evaluation of their durability in different conditions is still lacking in the literature. In this work, we report the fabrication of SLIPS based on a ceramic porous layer infused with different lubricants, namely perfluoropolyethers with variable viscosity and n-hexadecane; we investigate the durability of these surfaces by monitoring the evolution of their wetting behavior after exposure to severe environmental conditions like UV irradiation, chemically aggressive solutions (acidic, alkaline, and saline), and abrasion. Chemical composition and viscosity of the infused liquids prove decisive in determining SLIPS durability; especially highly viscous infused liquids deliver enhanced resistance to abrasion stress and chemical attack, making them candidates for applicable, long-lasting liquid-repellent surfaces.

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A Survey on Edge Performance Benchmarking

ACM Computing Surveys ◽

10.1145/3444692 ◽

2021 ◽

Vol 54 (3) ◽

pp. 1-33

Author(s):

Blesson Varghese ◽

Nan Wang ◽

David Bermbach ◽

Cheol-Ho Hong ◽

Eyal De Lara ◽

...

Keyword(s):

Large Scale ◽

Future Internet ◽

Coupled Systems ◽

Operational Conditions ◽

Loosely Coupled ◽

Performance Benchmarking ◽

The Past ◽

Geographically Dispersed ◽

Tightly Coupled ◽

History Of

Edge computing is the next Internet frontier that will leverage computing resources located near users, sensors, and data stores to provide more responsive services. Therefore, it is envisioned that a large-scale, geographically dispersed, and resource-rich distributed system will emerge and play a key role in the future Internet. However, given the loosely coupled nature of such complex systems, their operational conditions are expected to change significantly over time. In this context, the performance characteristics of such systems will need to be captured rapidly, which is referred to as performance benchmarking, for application deployment, resource orchestration, and adaptive decision-making. Edge performance benchmarking is a nascent research avenue that has started gaining momentum over the past five years. This article first reviews articles published over the past three decades to trace the history of performance benchmarking from tightly coupled to loosely coupled systems. It then systematically classifies previous research to identify the system under test, techniques analyzed, and benchmark runtime in edge performance benchmarking.

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Foundations for Systematic Evaluation and Benchmarking of a Mobile Food Logger in a Large-scale Nutrition Study

Proceedings of the ACM on Interactive Mobile Wearable and Ubiquitous Technologies ◽

10.1145/3397327 ◽

2020 ◽

Vol 4 (2) ◽

pp. 1-25

Author(s):

Jisu Jung ◽

Lyndal Wellard-Cole ◽

Colin Cai ◽

Irena Koprinska ◽

Kalina Yacef ◽

...

Keyword(s):

Large Scale ◽

Systematic Evaluation ◽

Nutrition Study

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Numerical Simulation of EPB Shield Tunnelling with TBM Operational Condition Control Using Coupled DEM–FDM

Applied Sciences ◽

10.3390/app11062551 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2551

Author(s):

Hyobum Lee ◽

Hangseok Choi ◽

Soon-Wook Choi ◽

Soo-Ho Chang ◽

Tae-Ho Kang ◽

...

Keyword(s):

Numerical Simulation ◽

Large Scale ◽

Tunnel Boring Machine ◽

Chamber Pressure ◽

Screw Conveyor ◽

Shield Tunnel ◽

Pressure Balance ◽

Operational Conditions ◽

Shield Tunnelling ◽

Epb Shield

This study demonstrates a three-dimensional numerical simulation of earth pressure balance (EPB) shield tunnelling using a coupled discrete element method (DEM) and a finite difference method (FDM). The analysis adopted the actual size of a spoke-type EPB shield tunnel boring machine (TBM) consisting of a cutter head with cutting tools, working chamber, screw conveyor, and shield. For the coupled model to reproduce the in situ ground condition, the ground formation was generated partially using the DEM (for the limited domain influenced by excavation), with the rest of the domain being composed of FDM grids. In the DEM domain, contact parameters of particles were calibrated via a series of large-scale triaxial test analyses. The model simulated tunnelling as the TBM operational conditions were controlled. The penetration rate and the rotational speed of the screw conveyor were automatically adjusted as the TBM advanced to prevent the generation of excessive or insufficient torque, thrust force, or chamber pressure. Accordingly, these parameters were maintained consistently around their set operational ranges during excavation. The simulation results show that the proposed numerical model based on DEM–FDM coupling could reasonably simulate EPB driving while considering the TBM operational conditions.

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Infrared Thermography Measurement for Vibration-Based Structural Health Monitoring in Low-Visibility Harsh Environments

Sensors ◽

10.3390/s20247067 ◽

2020 ◽

Vol 20 (24) ◽

pp. 7067

Author(s):

Jia-Hao He ◽

Ding-Peng Liu ◽

Cheng-Hsien Chung ◽

Hsin-Haou Huang

Keyword(s):

Structural Health Monitoring ◽

Infrared Thermography ◽

Mode Shape ◽

Health Monitoring ◽

Large Scale ◽

Frame Structure ◽

Harsh Environments ◽

Thermal Imager ◽

Heat Sources ◽

Structural Health

In this study, infrared thermography is used for vibration-based structural health monitoring (SHM). Heat sources are employed as sensors. An acrylic frame structure was experimentally investigated using the heat sources as structural marker points to record the vibration response. The effectiveness of the infrared thermography measurement system was verified by comparing the results obtained using an infrared thermal imager with those obtained using accelerometers. The average error in natural frequency was between only 0.64% and 3.84%. To guarantee the applicability of the system, this study employed the mode shape curvature method to locate damage on a structure under harsh environments, for instance, in dark, hindered, and hazy conditions. Moreover, we propose the mode shape recombination method (MSRM) to realize large-scale structural measurement. The partial mode shapes of the 3D frame structure are combined using the MSRM to obtain the entire mode shape with a satisfactory model assurance criterion. Experimental results confirmed the feasibility of using heat sources as sensors and indicated that the proposed methods are suitable for overcoming the numerous inherent limitations associated with SHM in harsh or remote environments as well as the limitations associated with the SHM of large-scale structures.

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Surveillance Models of Large-Scale ESP With High Viscosity Fluids and Gas

Volume 6: Materials Technology; Polar and Arctic Sciences and Technology; Petroleum Technology Symposium ◽

10.1115/omae2012-83534 ◽

2012 ◽

Author(s):

Lissett Barrios ◽

Stuart Scott ◽

Charles Deuel

Keyword(s):

Large Scale ◽

Two Phase Flow ◽

Electrical Current ◽

High Viscosity ◽

Viscous Fluids ◽

Phase Flow ◽

Centrifugal Pumps ◽

Operational Parameters ◽

Two Phase ◽

Operational Conditions

The paper reports on developmental research on the effects of viscosity and two phases, liquid–gas fluids on ESPs which are multi stage centrifugal pumps for deep bore holes. Multiphase viscous performance in a full-scale Electrical Submersible Pump (ESP) system at Shell’s Gasmer facility has been studied experimentally and theoretically. The main objectives is to predict the operational conditions that cause degradations for high viscosity fluids when operating in high Gas Liquid Radio (GLR) wells to support operation in Shell major Projects. The system studied was a 1025 series tandem WJE 1000. The test was performed using this configuration with ten or more pump stages moving fluids with viscosity from 2 to 200 cP at various speed, intake pressure and Gas Void Fractions (GVF). For safety considerations the injected gas was restricted to nitrogen or air. The ESP system is a central artificial lift method commonly used for medium to high flow rate wells. Multiphase flow and viscous fluids causes problems in pump applications. Viscous fluids and free gas inside an ESP can cause head degradation and gas locking. Substantial attempts have been made to model centrifugal pump performance under gas-liquid viscous applications, however due to the complexity this is still a uncertain problem. The determination of the two-phase flow performance in these harmful conditions in the ESP is fundamental aspects in the surveillance operation. The testing at Shell’s Gasmer facility revealed that the ESP system performed as theoretical over the range of single flowrates and light viscosity oils up to Gas Volume Fractions (GVF) around 25%. The developed correlations predict GVF at the pump intake based on the operational parameters. ESP performance degrades at viscosity higher than 100cp as compared to light oil applications, gas lock condition is observed at gas fraction higher than 45%. Pump flowrate can be obtained from electrical current and boost for all range of GVF and speed. The main technical contributions are the analysis of pump head degradation under two important variables, high viscosity and two-phase flow inside the ESP.

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Systematische Bewertung von FKV-Fertigungstechnologien*/Systematic evaluation of FRP manufacturing technologies - Technology evaluation by the example of large-scale series production of fiber-reinforced plastic (FRP) components

wt Werkstattstechnik online ◽

10.37544/1436-4980-2016-03-29 ◽

2016 ◽

Vol 106 (03) ◽

pp. 125-130

Author(s):

D. Hofbauer ◽

J. Greitemann ◽

M. Grammer ◽

J. Kaufmann ◽

G. Prof. Reinhart

Keyword(s):

Mass Production ◽

High Performance ◽

Large Scale ◽

Systematic Evaluation ◽

Series Production ◽

Fiber Reinforced ◽

Fiber Reinforced Plastic ◽

Reinforced Plastic ◽

Plastic Components ◽

Manufacturing Technologies

Hochleistungswerkstoffe wurden bisher nur für Spezialanwendungen eingesetzt, da hohe Materialkosten und eine geringe Reife der Fertigungstechnologien die Anwendung in der Großserie erschwert haben. Um die grundlegende Eignung der Technologien unter Beachtung der Produktanforderungen zu ermitteln, präsentiert dieser Fachbeitrag eine Methodik für die systematische Bewertung, die am Beispiel der Großserienfertigung von Bauteilen aus Faser-Kunststoff-Verbundwerkstoffen (FKV) erläutert wird.   The use of high-performance materials has so far been limited to special applications for reasons of high material costs and low maturity of manufacturing technologies. These facts avoided their use in mass production in the past. This paper presents a method for systematically evaluating technologies to determine their fundamental suitability for mass production. It is exemplified by large-scale series production of fiber-reinforced plastic components.

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Operational modifications for the development of nitrifying bacteria in a large-scale biological aerated filter and its impact on wastewater treatment

Water Science & Technology ◽

10.2166/wst.2018.447 ◽

2018 ◽

Vol 78 (8) ◽

pp. 1704-1714 ◽

Cited By ~ 1

Author(s):

François-René Bourgeois ◽

Frédéric Monette ◽

Daniel G. Cyr

Keyword(s):

Large Scale ◽

Oxygen Demand ◽

Bacterial Biofilm ◽

Nitrifying Bacteria ◽

Nitrification Rate ◽

Total Biomass ◽

Ammonia Oxidizing Bacteria ◽

Operational Conditions ◽

Nitrite Oxidizing Bacteria ◽

Aerated Filter

Abstract To develop a better understanding for fixed biomass processes, the development of a nitrifying bacterial biofilm, as well as the performance of treatment during modifications to operational conditions of a full-scale submerged biological filter were examined. The development of the nitrifying biofilm was investigated at four depth levels (1, 2, 4 and 5 feet). The result of bacterial subpopulations analyzed by qPCR relative to the physico-chemical parameters of the wastewater during the various tests (sustained aeration, modified backwash parameters and inflow restriction) revealed an increase of the relative presence of nitrifying microorganisms throughout the biofilm (especially for nitrite oxidizing bacteria (NOB)), but this was not necessarily accompanied by a better nitrification rate. The highest observed nitrification rate was 49% of removal in the test cell during backwashing conditions, whereas the relative ammonia oxidizing bacteria (AOB) population was 0.032% and NOB was 0.008% of the total biomass collected. The highest percentage of nitrifying bacteria observed (0.034% AOB and 0.18% NOB) resulted in a nitrification rate of 21%. The treatment of organic matter determined by measuring the chemical and biochemical oxygen demand (COD, CBOD5) was improved.

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Analysis of a Large-Scale Cooling System Fan Gearbox Loads

Volume 1: Aircraft Engine; Fans and Blowers; Marine; Honors and Awards ◽

10.1115/gt2017-64302 ◽

2017 ◽

Author(s):

Charles H. O. Lombard ◽

Daniel N. J. Els ◽

Jacques Muiyser ◽

Albert Zapke

Keyword(s):

Large Scale ◽

Cooling System ◽

Axial Flow ◽

Output Shaft ◽

Blade Loading ◽

Operational Conditions ◽

Power Stations ◽

Reverse Loading ◽

Air Cooled Condensers ◽

Input Side

South Africa’s coal-fired power stations use super heated steam to drive generator turbines. In arid regions, air-cooled condensers (ACCs) are used to condense the process steam. These ACCs consists of an array of over 200 axial flow fans, each driven by a motor via a reduction gearbox. Distorted fan inlet air flow conditions cause transient blade loading, which results in variations in output shaft bending and torque. A measurement project was conducted where the input and output shaft of such a gearbox were instrumented with strain gauges and wireless bridge amplifiers. Gearbox shaft speed and vibration were also measured. Torsional and bending strains were measured for a variety of operational conditions, where correlations were seen between gearbox loading and wind conditions. The input side experienced no unexpected loads from the motor or changing wind conditions, whereas output shaft loading was influenced by the latter. Digital filters were applied to identify specific bending components, such as the influence of fan hub misalignment and dynamic blade loading. Reverse loading of the gearbox was measured during the fan stop period, and vibration analysis revealed torsional and gearbox vibrations. This investigation documented reliable full scale ACC gearbox loads.

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Application of Miscible Ethane Foam for Gas EOR Conformance in Low-Permeability Heterogeneous Harsh Environments

SPE Journal ◽

10.2118/201189-pa ◽

2020 ◽

Vol 25 (04) ◽

pp. 1871-1883

Author(s):

Mohamad Salman ◽

Konstantinos Kostarelos ◽

Pushpesh Sharma ◽

Jae Ho Lee

Keyword(s):

Oil Recovery ◽

High Salinity ◽

Total Dissolved Solids ◽

Harsh Environments ◽

Low Permeability ◽

Type I ◽

Fracture Networks ◽

Operational Conditions ◽

Minimum Miscibility Pressure ◽

Carbon Dioxide Co2

Summary Unconventional plays pose a challenging set of operational conditions, including high temperature, high salinity, low permeability, and fracture networks. Aggressive development of these plays and the low primary recovery factors present an opportunity for using enhanced oil recovery (EOR) methods. This work presents a laboratory investigation of miscible ethane (C2H6) foam for gas EOR conformance in low-permeability, heterogeneous, harsh environments [<15 md, 136,000 ppm total dissolved solids (TDS) with divalent ions, 165°F]. The use of C2H6 as an alternative to carbon dioxide (CO2) offers several operational and availability strengths, which might expand gas EOR applications to depleted or shallower wells. Coupling gas conformance also helps improve displacement efficiencies and maximize overall recovery. Minimum miscibility pressure (MMP) displacement tests were performed for dead crude oil from the Wolfcamp Spraberry Trend area using C2H6 and CO2. Aqueous stability, salinity scan, and static foam tests were performed to identify a formulation. Subsequent foam quality and coreflood displacement tests in heterogeneous carbonate outcrop cores were conducted to compare the recovery efficiencies of three processes: gravity-unstable, miscible C2H6 foam; gravity-stable, miscible C2H6; and gravity-unstable, miscible C2H6 processes. Slimtube tests comparing C2H6 to CO2 resulted in a lower MMP value for C2H6. We identified a stable surfactant blend capable of Type I microemulsion and persistent foams in the presence of oil. Corefloods conducted with gravity-unstable miscible C2H6 foam, gravity-stable miscible C2H6, and gravity-unstable miscible C2H6 recovered 98.4, 61.9, and 42.6% oil originally in place, respectively. Our work shows that miscible C2H6 injection processes achieved significant recoveries even under gravity-unstable conditions. The addition of foam provides better conformance control, enhancing overall recovery at the laboratory scale, showing promise for field applications.

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Automatic detection of Long Method and God Class code smells through neural source code embeddings

10.36227/techrxiv.17206010.v1 ◽

2021 ◽

Author(s):

Aleksandar Kovačević ◽

Jelena Slivka ◽

Dragan Vidaković ◽

Katarina-Glorija Grujić ◽

Nikola Luburić ◽

...

Keyword(s):

Machine Learning ◽

Large Scale ◽

Negative Impact ◽

Source Code ◽

Systematic Evaluation ◽

Small Scale ◽

Code Smells ◽

Code Metrics ◽

Code Smell ◽

F Measure

Code smells are structures in code that often have a negative impact on its quality. Manually detecting code smells is challenging and researchers proposed many automatic code smell detectors. Most of the studies propose detectors based on code metrics and heuristics. However, these studies have several limitations, including evaluating the detectors using small-scale case studies and an inconsistent experimental setting. Furthermore, heuristic-based detectors suffer from limitations that hinder their adoption in practice. Thus, researchers have recently started experimenting with machine learning (ML) based code smell detection. This paper compares the performance of multiple ML-based code smell detection models against multiple traditionally employed metric-based heuristics for detection of God Class and Long Method code smells. We evaluate the effectiveness of different source code representations for machine learning: traditionally used code metrics and code embeddings (code2vec, code2seq, and CuBERT). We perform our experiments on the large-scale, manually labeled MLCQ dataset. We consider the binary classification problem – we classify the code samples as smelly or non-smelly and use the F1-measure of the minority (smell) class as a measure of performance. In our experiments, the ML classifier trained using CuBERT source code embeddings achieved the best performance for both God Class (F-measure of 0.53) and Long Method detection (F-measure of 0.75). With the help of a domain expert, we perform the error analysis to discuss the advantages of the CuBERT approach. This study is the first to evaluate the effectiveness of pre-trained neural source code embeddings for code smell detection to the best of our knowledge. A secondary contribution of our study is the systematic evaluation of the effectiveness of multiple heuristic-based approaches on the same large-scale, manually labeled MLCQ dataset.

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