Effect Of Surface Coatings Research Articles

Effect of Different Surface Coatings on Shelf Life and Quality of Guava (Psidium guajava L.) CV. Allahabad Safeda

Aims: To evaluate the potentiality of surface coatings for achieving extended shelf life with enhance fruit quality attributes in Guava under ambient storage condition.
 Study design: The lab experiment conducted in complete randomized design three replications on Allahabad safeda of Guava.
 Place and duration of study: The experiment was conducted during November 2019 at College of Horticulture, Sri Konda Laxman Telangana State Horticultural University, Rajendranagar, Hyderabad.
 Methodology: Guava freshly harvested fruits were coated with three Surface coatings viz. Aloe vera (12.5%, 25% & 50%), Chitosan (0.5%, 1.0% & 1.5%), citric acid (1%, 2% & 3%). The coated fruits were stored at ambient room condition. Periodically effects of surface coatings were observed for physiological loss in weight, Shelf Life (days), Firmness (Kg/cm 2), Total Soluble Solids (%), Titrable Acidity (%), Ascorbic Acid (mg/100g), Total Sugars (%), Reducing Sugars (%), Non-Reducing Sugars (%).
 Results: Surface coating physical parameters, fruits treated with T5-Chitosan (1%) showed minimum physiological loss in weight during storage, and least decay percentage. Among the treatments, highest shelf life (9.98 days), highest firmness (2.76 kg/cm2) was recorded in T5-Chitosan (1%) which was on par with T2-Aloe vera (25%) (9.67 days & 2.71 kg/cm2) while lowest shelf life was recorded in T10-Control (6.45 days). Among the treatments, T5- Chitosan (1%) recorded highest TSS (10.33 oB), highest ascorbic acid content (122.32 mg/100g), highest total sugar content, reducing sugar and least non reducing sugar content (9.72%, 6.02% & 2.84%) respectively followed by T2-Aloe vera 25% while least was noticed in T6-Chitosan 1.5% on 10th day of storage.
 Conclusion: surface coating of Chitosan1% substantially improved the shelf life with retaining better fruit quality attributes under ambient conditions.

The Effect of Surface Coating of Iron Oxide Nanoparticles on Magnetic Resonance Imaging Relaxivity

Iron oxide nanoparticles (IONPs) with acceptable biocompatibility and size-dependent magnetic properties can be used as efficient contrast agents in magnetic resonance imaging (MRI). Herein, we have investigated the impact of particle size and surface coating on the proton relaxivity of IONPs, as well as engineering of small IONPs' surface coating as a strategy for achieving gadolinium-free contrast agents. Accordingly, polymer coating using poly(isobutylene-alt-maleic anhydride) (PMA) with overcoating of the original ligands was applied for providing colloidal stability to originally oleic acid–capped IONPs in aqueous solution. In case of replacement of the original ligand shell, the polymer had been modified with dopamine. Furthermore, the colloidal stability of the polymer-coated IONPs was evaluated in NaCl and bovine serum albumin (BSA) solutions. The results indicate that the polymer-coated IONPs which involved replacement of the original ligands exhibited considerably better colloidal stability and higher proton relaxivity in comparison to polymer-coated IONPs with maintained ligand shell. The highest r2/r1 we obtained was around 300.

Effect of the Different Surface Coatings and Packaging Materials for Shelf Life and Quality of Guava (Psidium guajava L.) CV. Allahabad Safeda

Aims: To evaluate the potentiality of surface coatings and packaging for achieving extended shelf life with enhance fruit quality attributes in Guava under ambient storage condition.
 Study Design: The lab experiment conducted in complete randomized design three replications on Allahabad safeda of Guava.
 Place and Duration of Study: The experiment was conducted during November 2019 at College of Horticulture, Sri Konda Laxman Telangana State Horticultural University, Rajendranagar, Hyderabad.
 Methodology: Guava freshly harvested fruits were coated with two different coatings Chitosan (1%), Aloe vera gel (25%) and three different packaging materials viz., Polypropylene 100 gauge, HDPE 50 microns and LDPE 50 microns comprising of six treatments with four replications in Completely Randomized Design. Periodically effects of surface coatings were observed for physiological loss in weight, Shelf Life (days), Firmness (Kg/cm2), Total Soluble Solids (%), Titrable Acidity (%), Ascorbic Acid (mg/100g), Total Sugars (%), Reducing Sugars (%), Non-Reducing Sugars (%).
 Results: With respect to physical parameters, lowest decay percent (13.28%), minimum PLW (14.61%) was recorded in T2- Chitosan 1% + HDPE 50 microns and highest was recorded in T6- Aloe vera 25% + LDPE 50 microns (15.49% &18.80%) on 12th day of storage. Highest shelf life (12.91 days) was recorded in T2- Chitosan 1% + HDPE 50 microns which was at par with T5- Aloe vera 25%+ HDPE 50 microns (12.89 days) and lowest shelf life (11.25 days) was recorded in T1 - Chitosan 1% + PP 100 gauge. Highest TSS (10.33oB), From this study it could be concluded that surface coatings, packaging materials found to have influence on the shelf life and quality of guava. Among the packaging materials HDPE 50 microns was superior followed by PP 50 microns and LDPE 100 gauge.
 Conclusion: The combined effect of surface coatings and packaging materials revealed that T2- Chitosan 1% + HDPE 50 microns followed by T5- Aloe vera 25%+ HDPE 50 microns were found to be superior over other treatments with respect to physical, shelf life and quality parameters.

Investigations on the effect of surface coatings on the weldment properties on chromium manganese stainless steel gas tungsten arc welded plates

This paper reports the enhancements for the effects of specific fluxes such as Tungsten Carbide and Chromium Oxide on the weldment properties such as micro hardness, weld bead geometry and tensile strength obtained with Gas Tungsten Arc Welding Process (GTAW) applied to 6 mm thick Chromium Manganese stainless steel plates. The significant expense of Nickel has made Chromium Manganese stainless steel as an option for conventional 300 arrangement stainless steel. The two fluxes tungsten carbide and chromium oxide were utilized in powdered structure. The tensile test, micro hardness test and corrosion resistance test was conducted to reveal the effect of fluxes on the weldment properties. Results of tensile shows that considerable enhancement in tensile strength and elongation of about 20% increase in case of Chromium Oxide coated samples and 10% increase in case of Tungsten Carbide samples when compared to uncoated specimen. In case of microhardness, 10% increase is exhibited for coated samples compared with uncoated samples. The corrosion rate of coated samples found to be highly resistant for coated samples, which sums to be 300% more than that of uncoated samples. The effect of corrosion rate on the specimens was seen by conducting SEM analysis after the corrosion test. The SEM analysis uncovered that the coating covers the limits encompassing the inclusions and encloses dendrites which reduce the pitting corrosion of the parent metal.

Effectiveness of surface coatings in concrete: chloride penetration and carbonation

Effectiveness of surface coatings in concrete: chloride penetration and carbonation

High Efficiency Perovskite‐Silicon Tandem Solar Cells: Effect of Surface Coating versus Bulk Incorporation of 2D Perovskite

High Efficiency Perovskite‐Silicon Tandem Solar Cells: Effect of Surface Coating versus Bulk Incorporation of 2D Perovskite

Oxygen-Retentive Coatings for High-Voltage Cathodes

Using first-principle calculations we rationalize the effectiveness of surface coatings and dopants for oxygen retention at the surface of high-voltage cathodes. We explore amorphous coatings by implementing a “liquid-quench” process, in which heating, equilibration, and quenching are done through series of AIMD simulations. Using a density-based spatial clustering to differentiate the vibrational and translational motions for Li and O trajectories, we analyze the correlation between local environment and diffusion. To evaluate each dopant’s ability to suppress the surface oxygen loss, we calculate the relative oxygen release energy during delithiation with respect to the pristine cathode phase. Insights based on the atomic structure, and stability against high-voltage delithiation is considered and recommendations towards improved systems are made.

High Efficiency Perovskite‐Silicon Tandem Solar Cells: Effect of Surface Coating versus Bulk Incorporation of 2D Perovskite

AbstractMixed‐dimensional perovskite solar cells combining 3D and 2D perovskites have recently attracted wide interest owing to improved device efficiency and stability. Yet, it remains unclear which method of combining 3D and 2D perovskites works best to obtain a mixed‐dimensional system with the advantages of both types. To address this, different strategies of combining 2D perovskites with a 3D perovskite are investigated, namely surface coating and bulk incorporation. It is found that through surface coating with different aliphatic alkylammonium bulky cations, a Ruddlesden–Popper “quasi‐2D” perovskite phase is formed on the surface of the 3D perovskite that passivates the surface defects and significantly improves the device performance. In contrast, incorporating those bulky cations into the bulk induces the formation of the pure 2D perovskite phase throughout the bulk of the 3D perovskite, which negatively affects the crystallinity and electronic structure of the 3D perovskite framework and reduces the device performance. Using the surface‐coating strategy with n‐butylammonium bromide to fabricate semitransparent perovskite cells and combining with silicon cells in four‐terminal tandem configuration, 27.7% tandem efficiency with interdigitated back contact silicon bottom cells (size‐unmatched) and 26.2% with passivated emitter with rear locally diffused silicon bottom cells is achieved in a 1 cm2 size‐matched tandem.

Ab initio thermodynamic optimization of Ni-rich Ni–Co–Mn oxide cathode coatings

The effectiveness of surface coatings in improving the stability and cycling performance of cathodes has been demonstrated since they are first proposed in the 1990's. However, the progress since then is made mostly using the trial-and-error method. Herein, an automated electrochemical-chemical stability design scheme based on first-principles thermodynamics calculations of reaction models is presented to optimize coatings for Ni-rich nickel–cobalt–manganese oxide (NCM) cathodes. Given that the coating must possess a wider electrochemical window than the cathode without the occurrence of Li-ion redistribution at the cathode/coating interface, the reaction energies of both lithium insertion/extraction and decomposition process associated with the coating are used as one of the two screening criteria. As the coating is also required to be chemically stable in Li residues and hydrofluoric-acid containing liquid environment, the positive reaction energy achieved by adjusting molar ratio of the components is used as another criterion. Using these two screening criteria, we demonstrate that lithium-containing metal phosphates, rather than previously suggested Li-containing metal oxides, are the optimal coatings for Ni-rich NCM cathodes, which is confirmed experimentally. The proposed approach is general and can be used to find optimal coating materials for any other cathodes.

Effectiveness of Surface Coatings Against Intensified Sewage Corrosion of Concrete

Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, the strength, micrograph, mineral compositions and pore structure of concrete specimens after removing coatings were also studied. The results show that epoxy coal tar pitch coating (ECTPC) has the best effect of protecting concrete from the sewage corrosion. After being immersed in sewage for 90 days, the compressive strength of concrete coated with ECTPC is still as high as that of specimen immersed in water, and the cement paste has a high CH content and dense structure with low porosity, which mainly accounts for its excellent barrier property and certain antibacterial function. Cement-based bactericidal coating (CBC) also has good effectiveness to sewage corrosion of concrete. The strength and microstructure of concrete coated with CBC in sewage are still significantly superior to those of uncoated concrete. Although cement-based capillary crystalline waterproofing coating (CCCWC) is a good waterproof material, it is not suitable for the corrosion resistance of concrete in sewage. After 2 months corrosion, almost all of the CH crystals in coating reacted with the metabolic acid substance by microbes. Therefore, the strength and pore structure of concrete coated with CCCWC are only slightly superior to those of uncoated concrete. Overall, the protective effect of cement-based inorganic coatings is relatively poor.

Surface coatings select their micro and macrofouling communities differently on steel

Previous studies have shown the effect of surface coatings on biofouling; however, they did not take into account the interaction of the micro and macrofouling communities, the effect of substrate orientation and the zooplankton-zoobenthic coupling together. Therefore, the aim of this study was to evaluate the effect of Zn- and Cu2O-based coatings on micro and macrofouling on steel surfaces, while also observing the role of substrate orientation and zooplankton supply. An experiment was carried out in the Patos Lagoon Estuary in southern Brazil for three months between spring and summer, where ASTM-36 steel plates represented different coatings (Zn- and/or Cu2O-based) and orientations (vertical and horizontal). To assess the zooplankton supply, sampling was carried out weekly using a 200 μm plankton net. Zn-based coating positively affected microfouling density compared to uncoated surfaces. The same pattern was observed with macrofouling, associated with vagile fauna preference, which represented 70% of the settled macrofoulers. Cu2O-based antifouling painted surfaces showed the highest microfouling density inhibition, while Zn + Cu2O-based coating did not affect the bacteria adhesion but showed lower density compared to Zn-based coating alone. The coatings combination showed the highest invertebrate inhibition. In this way, the macrofouling community was more sensitive than microfouling was to the antifouling coatings tested. The substrate orientation only affected macrofouling, horizontal surfaces being more attractive than vertical. Meroplankton, tychoplankton and holoplankton were recorded on the surfaces, although their representation in plankton was not proportional to the recruits recorded on the substrates. This was probably due to fast dispersion, the interactions of other factors and/or ecological succession stage. Surface coating, substrate orientation, and zooplankton supply interacted with the biofouling process on steel in different ways depending on the organism evaluated. Therefore, copper oxide- and zinc-based coatings were not suitable as coatings to avoid the total biofouling establishment.

Effects of Surface Coating of Cellulose II-based MFC on Paper Properties

Effects of Surface Coating of Cellulose II-based MFC on Paper Properties

Effect of Surface Coating of CNC and CNC/Starch on Surface Properties and Barrier Properties

Effect of Surface Coating of CNC and CNC/Starch on Surface Properties and Barrier Properties

Bone regeneration of hollow tubular magnesium‑strontium scaffolds in critical-size segmental defects: Effect of surface coatings

Segmental defects are formidable challenges for orthopedic surgeons that are caused by large osseous defects such as open injury, comminuted fracture as well as other severe traumas and infection. Current treatment options have practical and clinical shortcomings, calling for innovative bone graft materials. This study is related to hollow tubular magnesium‑strontium (MgSr) alloy scaffolds with autologous morselized bone filled inside and three different coatings were individually applied on MgSr scaffolds, respectively, to study the effects of degradation and bioactivity of the grafts on new bone growth. The optimal coating method was screened using immersion tests, cell proliferation and adhesion, alkaline phosphatase (ALP) assay in vitro, and 4 weeks' implantation in a critical-size segmental defect in vivo. More new bone formation was observed by radiographic tests and histology along the ulna defects, when magnesium scaffold grafts were implanted. Meanwhile, depression occurred for blank control group with only autologous morselized bone filled, because of rapid absorption rate of morselized bone during initial implantation. Therefore, biodegradable MgSr alloy grafts showed their potential application in treating the critical-size segmental defects. As for different coating methods, CaP chemically deposited (CaP) coated sample showed least H2 evolution in vivo, demonstrating highest corrosion resistance and relative stable interfaces, however, the least beneficial ion release meanwhile. Micro-arc oxidation coating (MAO) degraded faster comparing with CaP, while with the main composition of MgO. They both indicate insufficient bioactivity in bone formation. The results suggest superior combination of bioactive surface, beneficial ions release and appropriate corrosion rate of Strontium phosphate conversion (SrP) coating, indicating superior comprehensive oeteoconductive and osteoinductive properties of coatings on hollow tubular MgSr alloy scaffold.

Signal enhancement in laser diode thermal desorption-triple quadrupole mass spectrometry analysis using microwell surface coatings.

Laser-diode thermal desorption (LDTD) is an ionization source usually coupled to triple quadrupole mass spectrometry (QqQMS) and specifically designed for laboratories requiring high-throughput analysis. It has been observed that surface coatings on LDTD microwell plates can improve the sensitivity of the analysis of small polar molecules. The objective of the present study is to understand and quantify the effect of microwell surface coatings on signal intensity of small organic molecules of clinical, environmental, and forensic interest. Experiments showed that the peak areas of diclofenac, chloramphenicol, salicylic acid, and 11-nor-9-carboxy-Δ9 -tetrahydrocannabinol obtained by LDTD-QqQMS increased by up to 3 orders of magnitude when using microwells coated with ethylenediaminetetraacetic acid (EDTA). Tests with different chelating agents and polytetrafluoroethylene as microwell surface coatings showed that nitrilotriacetic acid gave significantly higher peak areas for five out of the nine compounds that showed signal enhancement using chelating agents as coatings. Scanning electron microscopy studies of EDTA-coated and uncoated microwells showed that analytes deposited in the former formed more uniform and thinner films than in the latter. The enhancement effect of surface coatings in LDTD-QqQMS was explained mainly by the formation of homogenous and thinner layers of nanocrystals of analytes that are easier to desorb thermally than the layers formed when the analytes dry in direct contact with the bare stainless-steel surface. Chemisorption of some analytes to the stainless-steel surface of the microwell plate appeared to be a minor factor. Surface coatings widen the number of compounds analyzable by LDTD-QqQMS and can also improve sensitivity and limits of detection.

Effect of Surface Coating of Gold Nanoparticles on Cytotoxicity and Cell Cycle Progression.

Gold nanoparticles (GNPs) are usually wrapped with biocompatible polymers in biomedical field, however, the effect of biocompatible polymers of gold nanoparticles on cellular responses are still not fully understood. In this study, GNPs with/without polymer wrapping were used as model probes for the investigation of cytotoxicity and cell cycle progression. Our results show that the bovine serum albumin (BSA) coated GNPs (BSA-GNPs) had been transported into lysosomes after endocytosis. The lysosomal accumulation had then led to increased binding between kinesin 5 and microtubules, enhanced microtubule stabilization, and eventually induced G2/M arrest through the regulation of cadherin 1. In contrast, the bare GNPs experienced lysosomal escape, resulting in microtubule damage and G0/G1 arrest through the regulation of proliferating cell nuclear antigen. Overall, our findings showed that both naked and BSA wrapped gold nanoparticles had cytotoxicity, however, they affected cell proliferation via different pathways. This will greatly help us to regulate cell responses for different biomedical applications.

Silicon Quantum Dots Metal-Enhanced Photoluminescence by Gold Nanoparticles in Colloidal Ensembles: Effect of Surface Coating

In the present study, we report the photophysical properties of colloidal ensembles of silicon quantum dots (SiDs) and gold nanoparticles (AuNPs), particularly focusing on investigating metal-enhan...

Evaluating the Effect of Shear Stress on Graft-To Zwitterionic Polycarboxybetaine Coating Stability Using a Flow Cell.

The effect of surface coatings on the performance of antifouling activity under flow can be influenced by the flow/coating interactions. This study evaluates the effect of surface coatings on antifouling activity under different flows for the analyses of coating stability. This was done by exposing DOPA-PCB-300/dopamine coated polydimethylsiloxane (PDMS) to physiological shear stresses using a recirculation system which consisted of dual chamber acrylic flow cells, tygon tubing, flow probe and meter, and perfusion pumps. The effect of shear stress induced by phosphate buffered saline flow on coating stability was characterized with differences in fibrinogen adsorption between control (coated PDMS not loaded with shear stress) and coated samples loaded with various shear stresses. Fibrinogen adsorption data showed that relative adsorption on coated PDMS that were not exposed to shear (5.73% ± 1.97%) was significantly lower than uncoated PDMS (100%, p < 0.001). Furthermore, this fouling level, although lower, was not significantly different from coated PDMS membranes that were exposed to 1 dyn/cm2 (9.55% ± 0.09%, p = 0.23), 6 dyn/cm2 (15.92% ± 10.88%, p = 0.14), and 10 dyn/cm2 (21.62% ± 13.68%, p = 0.08). Our results show that DOPA-PCB-300/dopamine coatings are stable, with minimal erosion, under shear stresses tested. The techniques from this fundamental study may be used to determine the limits of stability of coatings in long-term experiments.

Effect of Surface Coating on Bond Strength between Etched Feldspar Ceramic and Resin-Based Luting Agents.

This study evaluated adhesive protocols (silane, silane and unfilled resin, and universal adhesive) of bond strength between feldspar ceramic and resin-based luting agents (RBLAs). Thirty ceramic disks were embedded into acrylic resin, polished, etched, and randomly divided into 6 groups: S-RC: silane (S) and light-cured resin cement (RC) (RelyX Veneer; 3M ESPE); SB-RC: S followed by bond (B) (Clearfil SE Bond, Kuraray) and RC; UA-RC: universal adhesive (UA) (Single Bond Universal; 3M ESPE) and RC; flowable composite resin (F) was used on groups S-F, SB-F, and UA-F, and luting agent cylinders were built. The response variables (n=20) were microshear bond strength (MPa), characteristic strength (σ0, MPa), and Weibull modulus (m). The RC groups presented similar bond strengths regardless of whether or not bond was used. The S-F group with only silane application showed the highest bond strength, while the universal adhesive showed the lowest bond strength. The reliability was only affected in the UA-RC group, which was lower than the S-F group. Silane application is fundamental since the universal adhesive only decreased the bond strength between the feldspar ceramic and the RBLAs. Overall, the use of unfilled resin did not positively influence bond strength.

Evaluation of the effect of surface coatings on protection of concrete against sewage-induced degradation based on gray correlation analysis

Surface coating is the most widely used measure in engineering projects for protecting concrete against sewage attack. In this study, three types of conventional surface coating, including epoxy coal tar pitch coating (ECTPC), cement-based capillary crystalline waterproofing coating (CCCWC), and cement-based bactericidal coating (CBC) were examined for such purpose, and their performance of resisting sewage, water, acid, abrasion, and microbial erosion was investigated. Moreover, the gray theory method was adopted to find out the primary index of coatings that affected their protection of concrete against sewage-induced degradation (SID). The results revealed that ECTPC provided the best protection for concrete against sewage attack, due to the joint effects of its water resistance, resistance to flow erosion and bactericidal function. For the two inorganic coatings, there was no apparent difference between them in the bond strength and wear time. Although the water resistance of CCCWC was better than that of CBC, its resistance to sewage attack was worse. This was mainly attributed to the bactericide component in CBC, only a small number of cells can be observed in the attached biofilm layer. The gray correlation analysis indicates that the resistance to microbial growth of coating is the most critical factor of the SID of concrete. Also, the coatings acid resistance had the lowest correlation degree with its resistance to SID. Therefore, the effect of killing microorganisms at the origin is better than that of preventing or slowing down the penetration of sewage. These findings can be used to guide the selection of coatings in concrete sewers to control SID.