Untreated Surface Research Articles

Enhancing the corrosion resistance of 2205 duplex stainless steel in molten carbonate salts by laser-surface texturing

Next-generation concentrated solar power (CSP) technology needs to work at high temperatures to increase its power generation efficiency. It represents overcoming some issues for the structural materials, such as corrosion mitigation. In the present work, the laser-surface texturing (LST) treatment is investigated as a surface modification method to mitigate corrosion of a duplex stainless steel for CSP structural material. Corrosion tests of duplex steel were carried out immersed in a static molten salt mixture of Li2CO3-Na2CO3-K2CO3 at 600 °C for 1000 h. Complementary microscopy, microanalysis and optical characterization techniques were used to analyse both the steel surface after LST and the oxide scales formed after corrosion tests. Results evidenced that the laser treatment favoured the formation of a denser oxide layer, improving its effectiveness as a protective barrier against further oxidation. Compared with an untreated surface, the laser-treated one significantly decreased the corrosion rate by 48 %.

Collision-Induced Unfolding, Tandem MS, Bottom-up Proteomics, and Interactomics for Identification of Protein Complexes in Native Surface Mass Spectrometry.

Endogenously occurring salts and nonvolatile matrix components in untreated biological surfaces can suppress protein ionization and promote adduct formation, challenging protein identification. Characterization of labile proteins within biological specimens is particularly demanding because additional purification or sample treatment steps can be time-intensive and can disrupt noncovalent interactions. It is demonstrated that the combined use of collision-induced unfolding, tandem mass spectrometry, and bottom-up proteomics improves protein characterization in native surface mass spectrometry (NSMS). This multiprong analysis is achieved by acquiring NSMS, MS/MS, ion mobility (IM), and bottom-up proteomics data from a single surface extracted sample. The validity of this multiprong approach was confirmed by the successful characterization of nine surface-deposited proteins, with molecular weights ranging from 8 to 147 kDa, in two separate mixtures. Bottom-up proteomics provided a list of proteins to match against observed proteins in NSMS and their detected subunits in tandem MS. The method was applied to characterize endogenous proteins from untreated chicken liver samples. The subcapsular liver sampling for NSMS analysis allowed for the detection of endogenous proteins with molecular weights of up to ∼220 kDa. Moreover, using IM-MS, collision cross sections and collision-induced unfolding pathways of enzymatic proteins and protein complexes of up to 145 kDa were obtained.

Investigation of the wear behavior of FeNi36 alloy cut by WEDM method under different loads

PurposeFeNi36 (Invar-36) alloy is widely used in the fabrication of molding tools in aerospace industries but there remains a need to improve its wear and friction performance due to its relatively low hardness. The formation of a heat affected zone (HAZ) on the surface of Invar-36 cut by wire electric discharge machining (WEDM) is promising to enhance its tribological properties. This study aims to investigate the tribological performance of WEDM-treated Invar-36 via a ball-on-disk tribometer in dry-sliding conditions.Design/methodology/approachThe untreated and WEDM-treated Invar-36 surfaces were reciprocated against an alumina ball at a sliding velocity of 40 mm/s, a stroke length of 10 mm and a sliding duration of 125 min under loads of 5, 10 and 20 N. The worn surfaces were characterized using a 2D profilometry and a scanning electron microscope equipped with energy-dispersive spectroscopy.FindingsThe results showed that the WEDM-treated surface had a superior friction coefficient and wear resistance in comparison to the untreated surface, due to the grown HAZ. There was found to be a 9.3%–11.4% decrease in the friction coefficient and a 47%–57% reduction in the wear volume after the WEDM treatment. Both the untreated and WEDM-treated Invar-36 surfaces found abrasion and plastic deformation as the dominant wear mechanisms.Originality/valuePrevious works have not focused on the tribological performance of the WEDM-treated Invar-36 extensively used for molding tools in aerospace industries. Our findings provide compelling evidence that the WEDM treatment improved the wear and friction performance of Invar-36 alloy because of the grown HAZ.

Biowaste valorization on pharmaceuticals and pesticides abatement in aqueous environments

This study focuses on the abatement of pharmaceuticals and pesticides in water using sustainable biosorbents. Adsorption kinetics and equilibrium measurements were performed to characterize the adsorption of fluoxetine hydrochloride (FLX), carbamazepine (CRB) and atrazine (ATZ) by raw pine bark. The amount of adsorbed pollutants by mass of adsorbent followed the order: FLX (0.652 mg/g) > ATZ (0.522 mg/g) > CRB (0.144 mg/g), explained by the different interactions between the untreated pine surface and the target pollutants, according to the adsorption mechanism proposed. The evaluation of chemically and thermically modified pine was also assessed. In terms of the overall entrapment capability, pine bark modified with HNO3 was shown to be the best biosorbent (1.95 mg/g). The economic feasibility of the biosorbents was evaluated through a detailed cost analysis. Among the performed modifications, the one with H2O2 was the most expensive procedure, 23.7 €/mmol (pollutants mixture) being the hydrochar production the less expensive, 1.1 €/mmol. Through desorption assays it was found that 100% of FLX, 98% of CRB and 30% of ATZ, respectively, can be recovered from raw pine, using 50% (v/v) acetonitrile solution. The recyclability of the natural biosorbent was evaluated by adsorption-desorption cycles. Pine bark can be regenerated and reused at least for two times, without losing its adsorption efficiency. A pre-pilot air-lift type reactor was investigated as an effective rehabilitation approach to treat contaminated water, for up-scale purpose. Using biowastes for emerging pollutants entrapment can be considered a sustainable water rehabilitation pathway, promoting a circular bioeconomy and environmental protection.

Open-atmosphere laser nitriding of austenitic steels to form wear-resistant surfaces

This study presents an interesting result based on the laser beam irradiation of austenitic steels in an open atmosphere, which enables the formation of a surface layer comprising a nitrogen solid solution rather than an oxide. First, a focused nanosecond pulsed Nd:YAG laser beam with a laser energy of 400 mJ·pulse−1 was used to irradiate an AISI 316 stainless steel. This formed a surface layer of ~3 μm thickness with ~12 at.% nitrogen solid solution, thereby enhancing the hardness of the AISI 316 stainless steel surface to ~380 HV, nearly twice that of the untreated surface. Consequently, wear resistance was improved by preventing plastic deformation and abrasive wear. Thereafter, similar laser beam irradiation of Inver42® and Kovar® steels resulted in the formation of nitrogen solid solution layers with a thickness of ~1.5 μm, which is lower than that of AISI 316 steel. Furthermore, their nitrogen contents were reduced to ~6 at.%. Consequently, the improvement in the surface hardness of the Inver42® and Kovar® steels was less than that of the AISI 316 stainless steel. These differences were attributed to their alloy compositions; for instance, Cr, which has a high affinity for nitrogen, might trap the available nitrogen, thereby contributing to an increase in the nitrogen content.

Superbiphilic Laser‐Microengineered Surfaces with A Self‐Assembled Monolayer Coating for Exceptional Boiling Performance

AbstractThe rapid advancement of engineering systems has spurred the search for innovative thermal management solutions. Boiling, as a phase‐change heat transfer method, has shown promise in heat dissipation, but non‐functionalized surfaces struggle with increasing cooling demands. To improve heat dissipation efficiency across different heat loads, functionalized surfaces with tailored wettability have been proposed. Separately, superhydrophilic and superhydrophobic surfaces each offer benefits and drawbacks in boiling applications but combining them on a single “biphilic” surface simultaneously harnesses their advantages. In this study, laser‐functionalized copper surfaces with spatially tailored wettability are developed by combining two‐step laser texturing with a self‐assembled monolayer coating, while focus is placed on the impact of the size and pitch of superhydrophobic spots. The developed functionalized surfaces exhibit exceptional boiling performance with heat transfer coefficients up to 299 kW m−2 K−1, a 434% enhancement over untreated surfaces. Optimal ratios of superhydrophilic and superhydrophobic areas and optimal spot pitch are identified. Additionally, varying behavior at different heat flux levels is observed, emphasizing the importance of considering thermal loads when determining the optimal surface pattern. This advancement in performance, along with the rapid and cost‐effective functionalization process, represents a significant breakthrough for enhanced thermal management applications.

Characterization of Functional Coatings on Cork Stoppers with Laser-Induced Breakdown Spectroscopy Imaging.

Evaluating the efficiency of surface treatments is a problem of paramount importance for the cork stopper industry. Generically, these treatments create coatings that aim to enhance the impermeability and lubrification of cork stoppers. Yet, current methods of surface analysis are typically time-consuming, destructive, have poor representativity or rely on indirect approaches. In this work, the use of a laser-induced breakdown spectroscopy (LIBS) imaging solution is explored for evaluating the presence of coating along the cylindrical surface and in depth. To test it, several cork stoppers with different shaped areas of untreated surface were analyzed by LIBS, making a rectangular grid of spots with multiple shots per spot, to try to identify the correspondent shape. Results show that this technique can detect the untreated area along with other features, such as leakage and holes, allowing for a high success rate of identification and for its performance at different depths, paving the way for future industry-grade quality control solutions with more complex surface analysis.

Flexural Strength of Glass Fiber Post Following Conditioning with Various Chemical Solutions Running Title: Flexural Strength of Fiber Post with Different Chemical Treatments

The aim of this study was to assess various chemical solutions on the surfaces of glass fiber post could affect its flexural strength. A total of 80 Glass Fiber posts were divided into eight groups (n=10) based on surface treatment, untreated surface (control), 10% hydrofluoric acid (HF) for 1 minutes, 10% HF for 2 min, 24% hydrogen peroxide (H2O2) for 4 min, 24% H2O2 for 10 min, 35% H2O2 for 4 min, 35% H2O2 for 10 min, and chloroform solution for 1 hour. Fiber posts were immersed in the solutions for the required amount of time and then rinsed and dried. Fiber posts were loaded in three-point bending test using a mechanical testing machine, data recorded and Flexural strength (σ) was measured. Statistical analysis revealed that the highest value of flexural strength was shown in the group treated with 24% H2O2for 4minfollowed by Chloroform group, so they have no significant effect on flexural strength. While the least value was shown in group treated with10% HF for 2min.Treatment with HF significantly decrease flexural strength for both application times. Treatment with H2O2 showed significant decrease only in group treated with 35% H2O2 for 10 min. It was concluded that strong acid etching of HF and long application time of higher concentration of H2O2 had adverse effect on fiber post flexural strength.

Valorization of calcium hypochlorite precipitate as a new source of heterogeneous catalyst development for biodiesel production: A preliminary experiment

One of the main problem related with liquid bleach production from calcium hypochlorite is the amount of precipitates generated and its consequent management. As a result, academic and industrial communities have been challenged with searching of a means for its valorization. Therefore, this research explores the application of the precipitate as a viable source of Ca-based heterogeneous catalyst development for the production of waste cooking oil methyl esters for the first-time. The catalyst was prepared by dividing the precipitates into three forms, viz. raw untreated (RC), heat treated (RC-TB), and NaOH impregnated plus thermally activated (RC-ITB). The prepared catalysts were efficiently characterized by XRF, XRD, FTIR, SEM, and BET techniques. The characterization results indicated that the catalysts are mainly composed of calcium metal in the form of oxides (CaO), calcite (CaCO3) and Portlandite (Ca(OH)2), which are the promising constituents of basic catalysts. The BET inspection of RC, RC-TB, and RC-ITB revealed the specific surface area of 8.509, 9.089, and 9.312 m2/g, respectively. At the same reaction conditions, the maximum biodiesel yield of 76.05 % was achieved by RC-ITB compared to RC-TB (62.57 %) and RC (19.74 %), because it's larger specific surface area and highest basic nature (pH = 12.65 at 1:5 w/v) improves the reaction catalysis through better catalyst-substrates interactions. The lower biodiesel yield was attained through the RC catalyst due to its untreated surface, lower specific area, and weak alkaline nature (pH value = 10.66 at 1:5 w/v). Furthermore, regardless of the amount of yield, almost similar fuel properties and functional groups of the products over the coded catalysts were observed. Generally, the possibility of calcium hypochlorite precipitate as a precursor of Ca-based heterogeneous catalyst has been effectively proven in this research, which could be very important for environmental safety and industrial resource integration.

Composition, Structure, and Wear Resistance of Surface Nanostructures Obtained by Electric Spark Alloying of 65G Steel

By a combination of the X-ray phase and fluorescence analyses, it was shown that a hardened layer formed during electric spark alloying of 65G steel using a processing electrode made of T15K6 hard alloy is a nanocrystalline material. The ratio of the crystalline and the amorphous phases in it was achieved by changing the discharge energy. Since an increase in the discharge energy leads to an increase in the surface roughness and its amorphization, there is an optimal value of the discharge energy at which the maximum wear resistance of the resulting nanocomposites is achieved. At E = 0.2 J, the wear resistance of the hardened layer is 7–10 times higher than that of an untreated surface.

Application of Laser Treatment in Adhesive Bonding of Liners to Polymethyl Methacrylate Denture Resins: A Systematic Review and Meta-Analysis.

Objective: This systematic review and meta-analysis aimed to assess the influence of laser treatment on adhesive bonding of liners to polymethyl methacrylate (PMMA) denture base resins. Methods: The focused question was: "Does the application of laser treatment (Intervention) influence the adhesive bonding strength (Outcome) of liners to PMMA denture base resins (Population) as compared with untreated or unconditioned surfaces (Control)?" In vitro and clinical reports as well as reports on influence of laser treatments on bonding strength of liners to PMMA denture resins in comparison with untreated surfaces were included. Reports without any control group[s], without any application of laser[s] for PMMA denture bases that did not utilize PMMA denture bases, and not evaluate bond strength of PMMA denture base resins were excluded. An electronic search was conducted on PubMed, Scopus, and Web of Science. Meta-analyses were performed for calculating the standard mean difference (SMD) with a 95% confidence interval (95% CI). Results: Nine of the 12 included studies found that laser irradiation treatment produced significant surface texture alterations of the PMMA denture base and improved the adhesion between the PMMA denture base and soft lining. According to the meta-analysis, tensile bond strength showed an SMD of -2.49% (95% CI: -3.89 to -1.08; p = 0.0005), suggesting a statistically significant difference between the control and test groups (i.e., favoring laser-treated samples than untreated samples). Regarding shear bond strength scores, the outcomes showed an SMD of -2.24% (95% CI: -3.79 to -0.69; p = 0.005), suggesting a statistically significant difference between the control and test groups (i.e., favoring laser-treated samples than untreated samples). Conclusions: Despite the high heterogeneity among the included studies, it can be concluded that laser treatment might improve the bonding strengths of liners to PMMA denture base resins as compared with untreated surfaces. To validate the aforementioned conclusions, further verification is required through the implementation of well-designed randomized controlled trials with large sample sizes.

Contamination- and Perturbation-Free Fluorescent Monitoring of Zn2+ in Suspensions using Crown Ether-Functionalized Magnetic Nanoparticles

This study aims to introduce a fluorescence-based chemosensing method for Zn2+ in aqueous suspensions and untreated surface waters, conditions which generally hinder the application of conventional optochemical sensing platforms. A macrocyclic fluoroionophore was covalently bonded to a silica-coated magnetic nanoparticle and applied according to a predetermined protocol for analyzing trace amounts of Zn2+ under rarely investigated conditions. Utilizing the reversible complexation of the immobilized fluoroionophore, rapid regeneration was carried out via simple acidification after the magnetic-assisted solid-phase extraction of the particles. Forming inclusion complexes with Zn2+ with the receptor units of the particles leads to a significant enhancement in fluorescence intensity at 370 nm, above the detection limit of 5 ppb, with a dynamic linear range of quantification of 15–3000 ppb in a pH range of 5.5–7.5. Practical applicability was confirmed by analyzing untreated river water and an aqueous suspension of pumpkin seed flour as real and relevant heterogeneous multicomponent samples of predetermined sample composition and natural Zn2+ content. Our practical approach aims to broaden the applicability range of optochemical sensing platforms for Zn2+.

On the laser surface pre-treatment to enhance the surface texture, wettability and adhesion bonding strength of aluminium 7075-T6 laminates

ABSTRACT In this study, a laser surface pre-treatment strategy was applied to aluminium 7075-T6 alloy, in which the laser power, speed and frequency were varied to determine the best modified surface property in terms of surface wettability. Surface texture, topography, roughness, contact angle and adhesive bonding strength of the treated surface were measured and characterised. Results showed that the laser-treated surface at a laser power of 30 W, speed of 1.2 m/s and frequency of 8 kHz provided the highest surface wettability by showing the lowest contact angle of 17°, which was attributed to the deeper surface cavities and higher surface roughness. The laser treatment increased the adhesion strength up to 8.5 MPa which was 45% higher than that of the untreated surface (of 5.9 MPa). Its adhesion strength nearly matched with that of the oxalic acid treatment. The laser-treated failed specimen shows predominantly adhesion–cohesion failure mode with a strong interfacial bonding. FTIR spectra confirmed the presence of required functional chemical groups of the adhesive after curing, demonstrating a strong bonding force and affinity between the adhesive and the modified surface. The findings clearly indicate that the laser surface pre-treatment would be a viable surface modification strategy without environmental and health hazard to provide adequate strength in the adhesively bonded joints.

Tribological and corrosion behaviour of medical grade 316LVM steel by low temperature hybrid gaseous nitriding and carburizing

This study approached a low temperature hybrid gaseous nitriding and carburizing at varying temperature and gas composition to develop S-phase layer on 316LVM steel. The hybrid gaseous treatment at 475 °C and 10 % CH4 developed a distinct S-phase layer that is harder (1444 ± 32 HV0.025) than untreated surface. The S-phase layers are effective in reducing specific wear rates by 67 % to 1.19 ± 0.05 × 10−3 mm3/Nm, coefficients of friction by 26 % to 0.49 ± 0.02, and corrosion rate by 23 % to 6.02 ± 0.32 µm/y. Both untreated and treated surfaces had dominant abrasive wear mechanisms but on treated surface spalling holes were observed. This research highlights low-temperature hybrid gaseous nitriding and carburizing is promising for improving 316 LVM steel surface for orthopedic.

Improving Fracture Resistance of 5Y-PSZ-based Three-unit Bridge Prosthesis.

5Y-PSZ-based zirconia dental restorations exhibit high translucency and good esthetics but have a higher fracture risk compared to 3Y-TZP. To investigate the effect of BruxZir SteelTM treatment on the fracture resistance of zirconia three-unit bridges prepared using 5Y-PSZ-based zirconia blanks. Three-unit zirconia bridges were milled using CAD/CAM from homogeneous bisque zirconia blanks (5Y-PSZ-based) supplied by various manufacturers and sintered. Their fracture resistance was analyzed by dynamic loading. For each zirconia blank, the fracture resistance of the sintered test restoration (cementation surface treated with BruxZir SteelTM) was compared with the sintered control restoration (untreated cementation surface). Finite Element Analysis (FEA) was used to analyze the stress distribution on the three-unit bridge under an axial load. The fracture resistance of the test restorations was significantly higher than that of the control restorations for all the manufacturers considered in this study (P < 0.05). Furthermore, the restoration made of BruxZirⓇ Esthetic treated with BruxZir SteelTM had the highest fracture resistance compared to the other restorations. In addition, the three-unit bridge restorations prepared from 5Y-PSZ-based zirconia blocks exhibited differences in grain size and fracture toughness depending on the presence or absence of BruxZir SteelTM treatment. The locations of high stresses under FEA correlated well with the fracture locations in the corresponding experimental test. FEA also demonstrated the improved performance of BruxZir Steel-treated sample compared to the control. The fracture resistance of 5Y-PSZ-based BruxZir SteelTM-treated three-unit bridges was significantly higher (min. 30%, max. 198%) than control.

Implications of cryogenic treatment on microstructure, phase formation, mechanical and tribological properties of tungsten carbide cutting bits with varying cobalt content for mining applications

This study aims to provide a comprehensive analysis on the effect of cryogenic treatment on two different grades of WC rock cutting bits (low cobalt grade: WC-9 wt% Co and high cobalt grade: WC-25 wt% Co). The cutting bits are exposed to cryogenic treatment at different holding time such as 12, 24 and 36 h. The treated and untreated bits are characterized for low temperature DSC, phase analysis, microstructural study, elemental composition, hardness, fracture toughness and scratch test. Phase shift was observed for both the cases due to the martensitic phase transformation from α-Co (fcc) to ε Co (hcp) during cryogenic treatment. This transition was confirmed with low temperature DSC analysis between −90 °C and − 60 °C. New η carbide particles (Co6W6C) was formed for WC-25%Co and no such carbides was found for WC-9%Co. CT 36 of WC-25%Co exhibited a higher level of precipitation of η carbides. The results show that CT has enhanced hardness for both low (14.08%) and high cobalt (23.34%) WC cutting bits compared to untreated bits whereas density is not altered evidently. CT 24 and CT 36 possessed higher hardness and lower fracture toughness for WC-9%Co and WC-25%Co respectively. Higher CoF and formation of tribo layer was observed for treated bits whereas untreated bit experiences surface fracture and cracks as a result of scratch test. As a finding, mining sectors can utilize cutting bits that have undergone sustainable cryogenic treatment for rock cutting applications.

Stability of plasma improved adhesive property of polytetrafluoroethylene surface

In this study, the authors investigated the wettability change of atmospheric-pressure-cold-plasma (APCP)-treated polytetrafluoroethylene (PTFE) surfaces with time under different storage temperatures and pressures, and the results indicate that low temperature can hinder wettability recovery. After storage for 5 days, the water contact angle (WCA) of PTFE stored at room temperature (25°C) recovered from 19 ± 2 to 54 ± 2°, while the WCA of PTFE stored at low temperature (−10°C) increased to just 42 ± 3°. Then, the mechanism contributing to the slower wettability recovery was investigated by analyzing surface chemical compositions through X-ray photoelectron spectroscopy and observing surface morphologies using atomic force microscopy. After 15-day storage, the oxygen (O) and nitrogen (N) contents decreased obviously, while the fluorine (F) content increased. The fluorine content of the sample stored at low temperature was 20% less than that of the sample stored at room temperature. In contrast, surface micromorphologies were unchanged during storage, and the surface roughness R a of each sample was around 7 nm. Finally, peel strength tests were conducted on APCP-treated PTFE surfaces stored at different temperatures, and the surfaces stored at low temperature maintained better adhesive properties. After 15 days of storage, the adhesive strength could still reach 400 N/m, which was 376% higher than that of the untreated surface. The research results are expected to facilitate practical applications of APCP modification and PTFE surfaces significantly.

LABORATORY STUDY ON THE SEDIMENTATION OF SURFACE WASTEWATER POLLUTANT COMPONENTS IN HISTORICAL PART OF SAMARA

The article discusses the existing drainage systems in Samara, the proposed project for the reconstruction of storm collector outlets located within the boundaries of the historical part of Samara.&#x0D; One of the factors of reservoir pollution (of Volga and Samara rivers) is untreated surface wastewater. The article specifies the outlets in the historical part of the city pernicious for the water reservoir.&#x0D; The study on the sedimentation of pollutant components contained in surface wastewater disposed from the historical part of Samara was held.&#x0D; As a result of the research, it was found that due to treatment facilities and storage tanks construction, as well as wastewater pumping into the household sewerage system, surface wastewater pumping will reduce the anthropogenic impact on the reservoir.&#x0D; It will also contribute to some extent to household waste dilution and increase the hydraulic load on urban sewage treatment plants.&#x0D; The water bodies of the water area of Samara are experiencing anthropogenic pressure, including due to untreated surface wastewater.&#x0D; The qualitative indicators of surface wastewater of a large industrial center have been studied on the example of the urban district of Samara. A list of negative indicators for water bodies has been determined; their maximal, average and minimal value ranges have been specified. It was revealed that the presented data will not have a negative impact on the centralized water disposal systems of settlements and urban districts.

Drag reduction in turbulent channel flow by gas perfusion through porous non-hydrophobic and hydrophobic interfaces: Part I

Skin-friction drag in liquid flows can be reduced by several methods including bubble injection into the near-wall region, air layer creation, air cavities, and applied super-hydrophobic coatings. The first three of these methods each has major drawbacks. In the fourth method, the depletion of the trapped air pockets on the super-hydrophobic surfaces (SHSs) in turbulent flows may cause a significant drag increase. To improve FDR in turbulent flows, a novel method is investigated that perfuses air through a porous medium with and without a hydrophobic treatment. A set of experiments has been conducted in a recirculating water tunnel at downstream-distance-based Reynolds numbers to 8.2million. The test model was a flat porous plate and the total wall shear stress was measured by a load cell apparatus. Air was perfused through such interfaces at mass flow rates to 50 L/min. It is noted that downstream persistence is not an issue with this technique as long as perfusion occurs near uniformly along the surface. The results showed that the method with maximum airflow exhibited a total drag reduction of around 10–25% with an untreated surface and about 20–30% with a treated surface.

Toward a better interpretation of the partial least squares regression models for fluoropolymers treated by dielectric barrier discharges at atmospheric pressure

AbstractIn this article, partial least squares regression was applied to a continuous dielectric discharge process aiming to modify the surface of a fluoropolymer. Cross‐validation was used to find the optimal number of latent variables that minimize the error from the model. Then, the key parameters affecting the process were highlighted with the variable importance on the projection (VIP) and the biplot exploratory graph produced from the algorithm. Finally, the model was used to predict additional data not included in the training set. The new predictions were used to assess the ability of the model to predict data outside of the training range. The applicability domain for this model was also discussed. The results showed that less prediction errors occurred when the surface modification remained close to the untreated fluoropolymer surface characteristics.