Coated Samples Research Articles

Influence of natural antifungal coatings produced by Lacto-fermented antifungal substances on respiration, quality, antioxidant attributes, and shelf life of mango (Mangifera indica L.)

Active coating systems are a promising postharvest strategy for managing quality attributes while controlling postharvest diseases of fresh fruit. This work aims to determine the respiration, quality, antioxidant attributes, and shelf life of fresh mango treated with different natural antifungal coatings produced by Lacto-fermented antifungal compounds. The respiration rates were modeled using the uncompetitive Michaelis-Menten model. Mango samples were coated with five different antifungal coating solutions: negative control (immersed in distilled water), positive control (coated with chitosan (CH)+Benomyl), coated with CH+antifungal substances produced by Lactobacillus plantarum ATCC8014 in palm kernel cake (PKCL1), and CH+antifungal substances produced by Lactobacillus fermentum ATCC9338 in palm kernel cake (PKCL2), and coated with pure CH and stored at 25 ± 2 °C. Mango samples treated with CH+Benomyl and CH+PKCL2 had a shelf life of up to 18 days, whereas CH+PKCL1, pure CH coated, and negative control samples had shelf lives of 17, 14, and 9 days, respectively. The difference in O2 and CO2 concentrations were not significant among coated samples, but they were significant between coated samples and the uncoated negative control. The uncompetitive Michaelis-Menten model exhibited good agreement with the respiration rates of fresh mango, and it was confirmed to have a good fit to explain the results such as quality, antioxidants, and shelf life in the study. Weight loss, color, flesh firmness, ascorbic acid (AA) content, and antioxidant properties were not significantly different among coating treatments, although they differed significantly between coated and uncoated negative controls. CH+PKCL2 was the best antifungal coating formulation to preserve fresh mango. It has performed similarly to the antifungal coating prepared by a commercial fungicide, Benomyl.

Prevalence of Malaria and Associated Factors among Malaria-Suspected Patients Attending Hamusit Health Center, Northwest Ethiopia: A Cross-Sectional Study.

Background Malaria is one of the major public health problems in developing countries like Ethiopia. Despite efforts to reduce the mortality and morbidity, the disease is still a prominent health problem in Ethiopia. This study, therefore, was undertaken to assess the prevalence of malaria and associated factors among symptomatic patients in Northwest Ethiopia. Methods A facility based cross-sectional study was conducted from February to March 2020 among 210 febrile patients attending Hamusit Health Center, Northwest Ethiopia. A structured questionnaire was used to collect data on sociodemographic characteristics and factors perceived to be associated with Plasmodium infection. Questionnaire data was collected through face to face interview. Thin and thick blood films were prepared from capillary blood buffy coat samples. Data were analyzed using Statistical Package for Social Sciences Software version 20. Results Out of 210 malaria-suspected participants, 61 (29.0%) were confirmed to be infected by Plasmodium species. Plasmodium falciparum and P. vivax monoinfections were detected in 41 (19.5%) and 10 (4.8%) participants, respectively. Mixed infection was detected in 10 (4.8%) participants. Female participants (AOR = 2.261; 95% CI: 1.118-4.571; P = 0.023) and those having family members with history of malaria (AOR =2.261; 95% CI: 1.264-5.340; P = 0.009) had higher odds of acquiring Plasmodium infection as compared to their counterparts. Using insecticide-treated bed net and draining stagnant water were the most commonly mentioned malaria prevention measures reported by 71.9% and 8.1% of the respondents, respectively. Conclusion Malaria contributes significantly for febrile illnesses in the study area. Therefore, community mobilization should be strengthen in order to improve implementation of malaria control activities and, hence, reducing the prevalence.

Thick elastomeric coating removal using tailored infrared- and infrared-sonication hybrid technology

We report an innovative, cost-effective, and eco-friendly coating removal technology that removes thick polyurethane-based elastomeric coatings without damaging the underlying metal or glass-polymer composite substrates. The developed technology eliminates the need for chemical- or media-based treatments, thus reducing environmental problems such as releasing toxic gases or suspended solid particles in the air. This was achieved using tailored infrared and infrared-ultrasonication treatments of the coated substrates that caused bond failure at the surface coat-substrate interface by selective absorption of IR and/or impinging of the topcoat with the ultrasonication technique. The degraded interfacial adhesion strength then allowed easy removal of the specialty coating with the application of a pull at a certain angle to the substrate-coating interface. The effect of different operating parameters such as time of irradiation, surface temperature, sonication power/intensity was investigated to determine the optimal conditions for coating removal. The treated and untreated coated samples were characterized by DSC, SEM, FTIR, peel-tester, embedded thermocouple/LABVIEW, and infrared thermography techniques. The energy analysis revealed that the fracture energy component was 4× lower on the treated sample than the untreated sample indicating reduced bond strength, which can be explained based on residual thermal stress generated due to the thermal coefficient mismatch and the interfacial cell dislocation. Also, coating from the treated sample could be removed 1.75× faster than from the untreated sample. Based on the cost analysis, the operation cost for this technology is meager compared to conventional and energy-intensive technologies such as laser ablation.

Impact of post-heat-treatment on the surface-roughness, residual stresses, and micromorphology characteristics of plasma-sprayed pure hydroxyapatite and 7%-Aloxite reinforced hydroxyapatite coatings deposited on titanium alloy-based biomedical implants

The biocompatible hydroxylapatite (Ca10(PO4)6(OH)2) (HA) coating is usually depositing on the titanium substrate to enhance the healing process of implant and to isolate it from the harsh body environment. However, poor mechanical properties of HA restrict its usage for orthopedic applications like hip and knee joints which have to bear the load. The biocompatibility is provided by HA and mechanical strength by the addition of reinforce with HA. Thermal post treatments have been mostly utilized to enhance the morphological and physicomechanical characteristics of as-deposition coatings. In the present research, the emphasis has been laid to analyze the outcome of thermal-processing on phases of hydroxyapatite in coatings developed by plasma spraying process. The surface-morphology of as-sprayed and thermally-processed, HA coated samples was studied using Scanning electron microscope (S.E.M.), Elemental-mapping, X-ray diffraction analysis (X.R.D.), and Fourier-transform infrared (F.T.-I.R.) spectroscopy techniques. The outcomes achieved from the X.R.D. analysis of the hydroxylapatite-coated samples after thermal-treatment reveal the formation of crystalline structure at 750 °C with some traces of CaO. Moreover, when the heat treatment was further done at 950 °C, the unwanted CaO was totally eliminated and coating with crystalline structure was obtained. No substrate element is visible in the X-ray mapping of coatings. The presence of ultrafine particles was observed on both substrates after the heat treatment of coatings at specified temperatures for 2hr in air. These ultrafine particles have the capability to bond with the bone and also helps for bone in-growth on their surfaces.

Characterizing and Analyzing the Tribological Behaviour of Diamond Coated Tungsten Carbide (WC)

In this research work, the deposition of diamond coating was done on the tungsten carbide (WC) substrate utilizing the the thermal Chemical Vapour Deposition (CVD) technique. The carbon precursor used for growing the diamond on the tungsten carbide (WC) substrate material was sugarcane bagasse. The tribological properties of deposited diamond coating were studied examined in this paper. For characterization of the developed coating, Field Emission Scanning Electron Microscope (FESEM), Raman spectroscopy and X-ray diffraction (XRD), were used to characterize the developed diamond coating on the substrate material. These processes were used to confirm the presence of diamond coating on the substrate. For inspecting the hardness of the developed diamond coated and un coated samples, the tests of micro-hardness were also executed. The values of the Vickers hardness for the un-coated and the diamond coated substrates were found to be 964.95 HV to 1457.48 HV respectively. This depicted a rise of 51% in the hardness of the un-coated WC inserts. As per ASTM G-99 standards tribological behaviour of the developed coated substrate was also the scope of this work using a pin-on-disc tribometer. The tribological tests showed improvement in the wear resistance of the diamond coated WC inserts as there was a decrease in the value of wear by 57.84 %. The value of the coefficient of friction (COF) also found to be decreased by 51.48%. This paper presents a combined study of using tribological tests and morphologic study showing the advantages of coating diamond on the tungsten carbide (WC) substrate.

Cyclic Oxidation Properties of the Nanocrystalline AlCrFeCoNi High-Entropy Alloy Coatings Applied by the Atmospheric Plasma Spraying Technique

Microcrystalline and nanocrystalline AlCrFeCoNi high-entropy alloy (HEA) coatings were applied on Inconel 718 superalloy using the atmospheric plasma spraying (APS) process. The high-temperature oxidation behavior of the microcrystalline and nanocrystalline AlCrFeCoNi HEA-coated superalloy was examined at 1100 °C under the air atmosphere for 50 cycles under cyclic heating and cooling (1 h for each cycle). The oxidation kinetics of both nanocrystalline- and microcrystalline-coated superalloys were accordingly analyzed by weight change measurements. We noted that the uncoated and coated samples followed the parabolic rate law of the oxidation. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDS), elemental mapping and X-ray photoelectron spectroscopy (XPS) were used to analyze the oxidized coated and uncoated samples. In the HEA-coated superalloy, Fe, Ni, Co and Al were oxidized in the inter-splat region, whereas the splats, which consisted mainly of Ni and Cr, remained unoxidized. Due to the formation of compact and adhesive thin NiO, CoO oxides and spinels together with the Al2O3 oxide scale on the surface of the coating during oxidation, the developed nanocrystalline HEA coating showed better oxidation resistance compared with the microcrystalline HEA coating.

Synthesis of ZnO/TiO2-Based Hydrophobic Antimicrobial Coatings for Steel and Their Roughness, Wetting, and Tribological Characterization

AbstractWe synthesized novel TiO2/ZnO-phosphate (TP/ZP) and polymethyl hydrogen siloxane (PMHS)-based two-layer hydrophobic coatings with potential antimicrobial properties tuned for application on steel substrates. The mathematical method of topological data analysis was applied to surface roughness data. Wetting characterizations showed stable hydrophobic behavior of the two-layer coated samples. Through tribological characterization, we compared the friction behavior of uncoated steel samples and steel samples coated with different coating materials. The coefficient of friction of uncoated base materials (ranging from 0.221 to 0.269) and the two-layer hydrophobic coatings (ranging from 0.234 to 0.273) indicated that the coatings confer hydrophobic properties to the substrates without a notable change in the friction behavior. We observed the correlations between the wetting and friction behaviors and the average roughness of the coated samples. Analysis of the micrographs of the scratched surfaces revealed preliminary information about the durability and abrasion resistance of the coatings.

Evaluation of solid particle erosion and electrochemical corrosion of plasma-sprayed WC/8YSZ coating on SS316

Plasma spray coating enhances the corrosion and wear resistance of the stainless steel structures installed in marine applications. Hence, it is imperative to study the effectiveness of various coating combinations on the material’s performance. The present work investigates the effects of three different plasma-sprayed coatings on the wear and corrosive resistance of austenitic stainless steel (SS316). The three compositions of the coating were prepared using (i) Tungsten carbide (WC), (ii) 8 wt%. Yttria Stabilized Zirconia (8YSZ), and (iii) 50 wt%. Tungsten carbide (WC) with 50 wt%. Yttria Stabilized Zirconia (8YSZ). Experiments were conducted as per ASTM G76 to determine the erosive wear with a mixture of high-velocity air and Al2O3 abrasive particles. The corrosive medium used in the electrochemical polarisation tests was 3.5 wt%. NaCl. A scanning electron microscope (SEM) was used to examine the surface morphology of the eroded and corroded coatings. Energy Dispersive x-ray Analysis (EDAX) and X Ray Diffractrometry (XRD) analysis were carried out to reveal the phase composition, elemental distribution, and lattice parameters of uncoated and coated samples. The study reveals that the composite coating (WC + 8YSZ) have superior wear resistance when exposed to a high-velocity erodent. Due to the robust particle adhesion and cohesiveness of the (WC + 8YSZ) composite coating, crack initiation and propagation are rarely found on the surface of the composite coating, as evidenced by the surface wear morphology analysis. Further investigation reveals that the 8YSZ coating has excellent corrosion resistance. The SEM-based corrosive wear topography analysis reveals that the 8YSZ phase on the coated surface acts as a diffusion barrier to the electrolytic medium and a passive protective layer over the coating. Consequently, the micro-chipping of particles during exposure to the corrosive medium is prevented.

Mechanical and microMechanical and microstructural characterization of yttria-stabilized zirconia (Y2O3/ZrO2; YSZ) nanopartstructural characterization of yttria stabilized zirconia (Y2O3/ZrO2; YSZ) nanoparticles reinforced WC-10Co-4Cr coated turbine steel

The aim of this paper is to investigate the WC-10Co-4Cr coatings reinforced with 5 % and 10 % of yttria-stabilized zirconia (Y2O3/ZrO2; YSZ) nanoparticles deposited on the CA6NM turbine steel by using the high-velocity oxy-fuel (HVOF) thermal spraying technique. In the HVOF technique, the hot jet of the semi-solid particles strikes against the workpiece and creates a layer of coating of varying thickness on the substrate material. The coatings fabricated with HVOF were analyzed by scanning electron microscope (SEM) / energy-dispersive x-ray spectroscopy (EDS). The phase identification of a crystalline material was made with the x-ray diffraction (XRD) technique. The mecha­nical properties in terms of porosity, surface roughness and microhardness of the nanocomposite coatings were also evaluated. The SEM/EDS analysis showed that dense and homogeneous coatings were developed by the reinforcement of YSZ nanoparticles. The peaks of XRD graphs of WC-10Co-4Cr coating reinforced with 5 and 10 % of YSZ nanoparticles revealed that the WC was present as a major phase and W2C, Co3W3C, Co, Co6W6C, Co6W and Y2O3/ZrO2 nanoparticles were observed as a minor phase. The porosity level decreased up to 42 and 56 % by the addition 5 and 10 % of YSZ nanoparticles as compared with conventional WC-10Co-4Cr coating. The surface roughness values for WC-10Co-4Cr conventional coating, 95 % (WC-10Co-4Cr) + 5 % YSZ and 90 % (WC-10Co-4Cr) + 10 % YSZ nanocomposite coated samples were found to be 5.03, 4.89 and 4.28 respectively. The nanocomposite coatings reinforced with 10 % YSZ nanoparticles exhibited the highest microhardness value (1278 HV). The WC-10Co-4Cr coatings reinforced with 10 % of YSZ nanoparticles resulted in low porosity, low surface roughness and high microhardness. During the coating process, the nanoparticles of YSZ flow into the pores and are dispersed in the gaps between the micrometric WC particles and provide a better shield to the substrate material. The WC-10Co-4Cr with 10 % of YSZ nanoparticles showed better results in terms of mecha­nical and microstructural properties during the investigation.

Effect of methane flow rate on gas-jet MPCVD diamond synthesis

The paper describes synthesis of diamonds by the method of gas-jet deposition with microwave activation of precursor gases. This method involves the use of a supersonic jet for delivering the components activated in the discharge chamber to the substrate located in the deposition chamber. A series of experiments was carried out with different amounts of methane supplied at a hydrogen flow rate of 8000 sccm. The obtained samples of diamond coatings were studied by scanning electron microscopy and Raman spectroscopy. The temperature of the mixture and the intensities of H, CH, and C2 lines in the plasma of the discharge chamber were measured by optical emission spectroscopy. The values of pressure and temperature in the discharge chamber were used to estimate the composition of the mixture. Thus, the numerical dependences of the molar concentrations of CH3, CH, C2 and C2H2 on the initial concentration of methane have been obtained. These dependences are in qualitative agreement with the dependences of the intensities of H, CH, and С2 lines. The numerical-experimental study performed allows us to conclude that the optimal value of methane concentration in the supplied mixture for the gas-jet deposition method in the considered range of parameters is about 1%.

Novel use of ctDNA to identify locally advanced and metastatic upper tract urothelial carcinoma.

543 Background: Upper tract urothelial carcinoma (UTUC) is an aggressive cancer for which use of neoadjuvant chemotherapy (NAC) is limited by suboptimal clinical staging prior to nephroureterectomy. Detection of circulating tumor DNA (ctDNA) is associated with locally advanced and metastatic urothelial carcinoma of the bladder and may help identify UTUC patients who would benefit from NAC. Here we examine the feasibility and utility of plasma ctDNA in the diagnosis of non-organ confined high-risk UTUC. Methods: Patients with high-grade cTa-T2 UTUC without radiographic evidence of metastatic disease undergoing up-front radical nephroureterectomy (RNU) were prospectively accrued. Blood was collected preoperatively on the day of surgery, and plasma and buffy coat were processed for extraction of ctDNA. FFPE samples from RNU were used for tissue genomic DNA extraction. Next-generation sequencing (NGS) was used for variant profiling. Plasma and somatic tissue mutations were called by comparing with matched buffy coat samples. Detection of cancer variants with a mutation allele frequency (MAF) ≥ 0.25% and hotspot variants with a MAF down to 0.1% were reported for plasma samples targeted by a NGS panel (PredicineCARE). Variants with a MAF ≥ 5% and hotspot variants with a MAF down to 2% were reported for FFPE samples. Results: NGS analyses of matched FFPE and plasma samples were successfully performed for all 15 accrued UTUC patients. Alterations in MYC amplification (62%), TERT promoter (62%), TP53 (38%), FGFR3 (31%), ERBB2 (25%), ARID1A (19%), and PIK3CA (19%) were demonstrated in urothelial tumor tissue. Matched plasma ctDNA showed prevalent alterations in the TERT promoter (47%), TP53 (30%), ARID1A (20%), ERBB2 (20%), FGFR3 (20%), and PIK3CA (17%). Five patients (33%) had detectable plasma ctDNA mutations concordant with tumor-based genotypes using the targeted NGS panel. All patients with detectable preoperative ctDNA had advanced staging (≥pT2 or ≥pN1) and lymphovascular invasion on final pathology, resulting in a 71.4% sensitivity. The panel was 100% specific with no patients with pTis, pTa, or pT1 and pN0 having detectable concordant ctDNA mutations. Conclusions: Prospective ctDNA analysis using a targeted NGS panel is a feasible nonsurgical approach to prediction of high-risk UTUC and has the potential for identification of upper tract urothelial cancer patients that may benefit from NAC.

Front Cover: Synergistic Effects of Surface Coating and Bulk Doping in Ni‐Rich Lithium Nickel Cobalt Manganese Oxide Cathode Materials for High‐Energy Lithium Ion Batteries (ChemSusChem 4/2022)

The Front Cover shows multiple treatment choices for the modification of cathode active materials for lithium-ion batteries. Like for a car wash program, the treatment will typically result in an improvement of the status quo. However, the best treatment procedure will only become clear if all options are explored. In the present work, this means to not only investigate various coated samples, but also samples modified via the same heat-treatment without coating. More information can be found in the Research Article by Friederike Reissig et al.

Impact of hemolysis on multi-OMIC pancreatic biomarker discovery to derisk biomarker development in precision medicine studies

Cancer biomarker discovery is critically dependent on the integrity of biofluid and tissue samples acquired from study participants. Multi-omic profiling of candidate protein, lipid, and metabolite biomarkers is confounded by timing and fasting status of sample collection, participant demographics and treatment exposures of the study population. Contamination by hemoglobin, whether caused by hemolysis during sample preparation or underlying red cell fragility, contributes 0–10 g/L of extraneous protein to plasma, serum, and Buffy coat samples and may interfere with biomarker detection and validation. We analyzed 617 plasma, 701 serum, and 657 buffy coat samples from a 7-year longitudinal multi-omic biomarker discovery program evaluating 400+ participants with or at risk for pancreatic cancer, known as Project Survival. Hemolysis was undetectable in 93.1% of plasma and 95.0% of serum samples, whereas only 37.1% of buffy coat samples were free of contamination by hemoglobin. Regression analysis of multi-omic data demonstrated a statistically significant correlation between hemoglobin concentration and the resulting pattern of analyte detection and concentration. Although hemolysis had the greatest impact on identification and quantitation of the proteome, distinct differentials in metabolomics and lipidomics were also observed and correlated with severity. We conclude that quality control is vital to accurate detection of informative molecular differentials using OMIC technologies and that caution must be exercised to minimize the impact of hemolysis as a factor driving false discovery in large cancer biomarker studies.

Short- and long-term reproducibility of the COMET assay for measuring DNA damage biomarkers in frozen blood samples of the EPIC-Heidelberg cohort

The comet assay is widely used for quantification of genomic damage in humans. Peripheral blood derived mononuclear cells (PBMCs) are the most often used cell type for this purpose. Since the comet assay can be performed in an enhanced throughput format, it can be applied to large sample collections such as biobanks. The European Prospective Investigation into Cancer and Nutrition (EPIC) study is one of the largest existing prospective cohort studies, and the German Cancer Research Institute (DKFZ) in Heidelberg is a participating center with 25.000 frozen blood samples stored from around 25 years ago, enabling retrospective assessment of disease risk factors. However, experience with decades long frozen samples in the comet assay is so far missing. In Heidelberg, 800 study participants were re-invited twice between 2010 and 2012 to donate further blood samples. Here, we analyzed 299 Heidelberg-EPIC samples, compiled from frozen PBMC and buffy coat preparations selected from the different sampling time points. In addition, 47 frozen PBMC samples from morbidly obese individuals were included. For buffy coat samples, we observed a poor correlation between DNA damage in the same donors assessed at two sampling time points. Additionally, no correlation between DNA damage in buffy coat samples and PBMCs was found. For PBMCs, a good correlation was observed between samples of the same donors at the two time points. DNA damage was not affected by age and smoking status, but high BMI (>30; obesity) was associated with increased DNA damage in PBMCs. There was no indication for a threshold of a certain BMI for increased DNA damage. In conclusion, while 25 year-long stored buffy coat preparations may require adaptation of certain experimental parameters such as cell density and electrophoresis conditions, frozen PBMC biobank samples can be analyzed in the comet assay even after a decade of storage.

GroEL Chaperonin-Based Assay for Early Diagnosis of Scrub Typhus.

A point-of-care diagnostic for early and rapid diagnosis of scrub typhus caused by Orientia tsutsugamushi is required for prompt and proper treatment of patients presenting with undifferentiated febrile illnesses. In this study, an immunochromatographic antigen detection test kit (ICT AgTK) that targets the highly conserved O. tsutsugamushi 60 kDa GroEL chaperonin (heat shock protein 60) was developed. E. coli-derived recombinant GroEL expressed from DNA coding for the consensus sequence of 32 GroEL gene sequences extracted from the GenBank database was used to immunize rabbits and mice. Rabbit polyclonal antibodies (pAb) were used for preparing a gold-pAb conjugate, and the rGroEL-specific mouse monoclonal antibody was used as the antigen detection reagent at the ICT test line. In-house validation revealed that the ICT AgTK gave 85, 100 and 95% diagnostic sensitivity, specificity and accuracy, respectively, compared to the combined clinical features and standard IFA when tested on 40 frozen serum samples. The test kits correctly identified 10 scrub typhus samples out of 15 fresh plasma/buffy coat samples of patients with febrile illnesses. For independent laboratory validation, the ICT AgTK was sent to one provincial hospital. The ICT AgTK utilized by the hospital medical technologist correctly identified six scrub typhus samples out of 20 serum samples of patients with fever, as confirmed by specific IgM/IgG detection by IFA. The ICT AgTK is easy to perform with rapid turn-around time. It has the potential to be used as an important tool for on-site and early scrub typhus diagnosis by allowing testing of freshly collected samples (serum, plasma or buffy coat), especially in resource-limited healthcare settings.

Experimental Study of effect of Powder Coating thickness and layers on Hardness and Corrosion properties of Carbon Steel Material

Powder coating is one of the coating techniques that are widely used today as a substitute for coating using liquid painting. In this research, we report on the effect of the various layers of powder coating on the hardness and corrosion rate of the material. Three different layers of variation were observed with 1, 2, and 4 layers to obtain the best results. The cleaning process was applied before coating the samples. The coating process was performed in a special room/box to avoid contact with air and contamination from the outside environment with a spraying distance of about 20-30 cm. The morphology is compact and bigger grains are seen to be emerging in the 1 layer deposition. Many grains are visible, and uniform grains are distributed in the 2 layers deposited. For the 4 layers, due to higher layer deposition incorporation, the grain size is seen to be enlarged due to the merging of smaller grains with each other ultimately increasing the grain size. The uncoated material has a corrosion rate of 0.505 mm/year which means fair for the relative corrosion resistance. The coated samples have a corrosion rate of 0.353, 0.252, and 0.354 mm/year for the 1 layer, 2 layers, and 4 layers, respectively. Based on the calculation, the average number of the Rockwell hardness of un-coated and coated samples for the 1 layer, 2 layers, and 4 layers, respectively were estimated at about 70, 78, 79, and 58 HRB, respectively. The highest average hardness value is in sample B with 2 layers of 79 HRB. The lowest average hardness value is in sample B with 2 layers of 58 HRB. The lowest performance of sample D with 4 layers confirms the result as shown in the corrosion rate result.

Optimization of Cold Spray Process Inputs to Minimize Porosity and Maximize Hardness of Metal Matrix Composite Coatings on AZ31B Magnesium Alloy

In this investigation, the development of an empirical relationship to determine the porosity and microhardness of the coatings through low‐pressure cold‐sprayed (LPCS) aluminum alloy/alumina metal matrix composite (MMC) deposit. Spray parameters like temperature, standoff distance (SOD), and powder feed rate play an essential part in the determination of the coating effectiveness. In this study, 3 variables, 5 levels of central composite rotatable design (CCD) were used to decrease the total count of the experimentation. A mathematical model has been developed to evaluate the porosity and hardness of the coated samples along with LPCS spray parameters, and the model’s applicability was inspected by ANOVA. Utilizing response surface methodology, spray parameter optimization was carried out. The deposit developed by optimal spray parameters produces the lowest surface porosity of 3.31 vol.% and a higher hardness of 137.21 HV compared with other coated samples. It is validated through the response graph. As a result, the optimized parameters for aluminum alloy/alumina metal matrix composite (MMC) coatings via LPCS are 500 degrees Celsius, 10 mm SOD, and 20 grams/min powder feed rate.

Development of a Graphite Coating and Its Transfer from Batch to Coil Process for Application in PEMFC for Hydrogen-Powered Vehicles

In the present paper, coating systems consisting of a metallic corrosion barrier and a conductive graphitic carbon layer were deposited by a DC vacuum arc process. The coatings were developed in a batch process for application in the polymer electrolyte membrane fuel cell (PEMFC), and transferred to a continuous coil process to facilitate industrial mass production. The coating samples in the coil process had to achieve comparable results to the samples produced in the batch process, to meet the requirements of the environment prevailing in the fuel cell.The transfer to roll-to-roll processes is a crucial factor for commercial upscaling of PEMFC production. The experimental results showed that the electrical conductivity and corrosion resistance of the samples in the coil process were significantly improved compared to the uncoated base material and showed comparable performance to batch coated samples. X-ray photoelectron spectroscopy (XPS) was performed to determine the depth profile and the surface composition. Additional measurements were recorded for the contact resistances using the four-wire sensing method as well as corrosion resistance using potentiodynamic methods.

Effect of electroplating temperature on microstructure, corrosion, and wear behavior of Ni-P-W-TiO2 coating

Nickel-phosphorus-titanium oxide coating was fabricated on the AISI 304L steel substrate using the electroplating method. Electroplating was performed at temperatures of 55, 60 and 65 °C, and the effect of electroplating temperature on microstructure, corrosion behavior, and wear behavior was investigated. The coatings were characterized by use of scanning electron microscopy (SEM). In order to investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were performed in 3.5% of NaCl aqueous solution. A pin on disk test was employed to investigate the wear resistance of uncoated and coated samples. Sample micro-hardness was also measured by the Vickers hardness test. The results of potentiodynamic polarization and electrochemical impedance spectroscopy tests results showed that the coating created at temperature of 60 °C had the highest corrosion resistance (7058 Ω.cm2) compared to coated sample at temperature of 55 °C (2115 Ω.cm2) and 65 °C (2289 Ω.cm2). Also, the results of the wear and micro-hardness test showed that composite coating formed at temperature of 60 °C had the highest wear resistance and micro-hardness (677 Vickers) compared to coated sample at temperature of 55 °C (411 Vickers) and 65 °C (536 Vickers).

Prevalence of Viral Neoplastic Diseases with Special Reference to Avian Leukosis and their Infectious Status in Different Pure Line Indigenous Chickens

Viral neoplastic diseases in poultry causes huge economic loss all over the world. The prevalence of avian leukosis in different indigenous breeds of chicken is not known and needs to be addressed for its effective control. A study was designed to record the prevalence of viral neoplasms in poultry, screening of avian leukosis virus/viruses (ALV) antigen in various pure line chicken, and the infectious status of ALV (viremia or shedding) in indigenous birds. Routine necropsy was carried out to identify the birds that were died of neoplasm and the representative samples were collected. Out of 4195 birds necropsied, 90 birds were recorded with neoplastic lesions in various organs with a prevalence of 2.1%. Grossly, tumor lesions were recorded in various organs in which the high frequency of tumors were recorded in liver, spleen, and kidney. Histopathological examination revealed 13.5% of the samples had myeloid leukosis, 25.2% were lymphoid leukosis, 20.3% were histiocytic sarcomas and 40.7% were Marek’s disease. PCR screening of the tumor samples revealed the prevalence rate of 45.5% Marek’s disease virus (MDV), 53.3% ALV, and 1.1% reticuloendotheliosis virus (REV). Co-infections of MDV and ALV were recorded in 37.7% (34/90) samples and MDV, ALV, and REV were recorded in 1.1% (1/90) samples. Among ALV positive cases, 54.1% (26/48) were positive for ALV E and 25% (12/48) were positive for ALV J. Screening of ALV p27 antigen by antigen ELISA in various pure line chickens revealed the prevalence rate of 76.3% in Kadaknath, 73.5% in Ghagus, 76.5% in Aseel, 20.1% in PB-1, 18.8% in PB-2, 19.6% in PD-1, 14.3% in PD-4 and 8.6% in CB. Further molecular detection of ALV was carried out in buffy coat and albumen samples from the birds of Kadaknath, Ghagus, and Aseel that showed high SPR value to determine the infectious status of the ALV. Infectious status of ALV in the birds revealed 40% in Kadaknath, 68.4% in Ghagus and 85.7% in Aseel were viremic shedders (V+S+); 33.3% in Kadaknath, 10.5% in Ghagus and 0% in Aseel were viremic non shedders (V+S-); 16.6% in Kadaknath, 10.5% in Ghagus and 14.2% in Aseel were non viremic shedders (V-S+). This is the first study that documented the prevalence of ALV in different indigenous pure line birds and their infectious status in India.