Accelerating Open Access.
MDPI is a pioneer in scholarly open access publishing
and has supported academic communities since 1996.
Open AccessArticle
Development of a Model for Performance Analysis of a Honeycomb Thermal Energy Storage for Solar Power Microturbine Applications
Energies 2019, 12(20), 3968; https://doi.org/10.3390/en12203968 (registering DOI) - 18 Oct 2019
Abstract
Solar power microturbines are required to produce steady power despite the fluctuating solar radiation, with concerns on the dispatchability of such plants where thermal energy storage may offer a solution to address the issue. This paper presents a mathematical model for performance prediction [...] Read more.
Solar power microturbines are required to produce steady power despite the fluctuating solar radiation, with concerns on the dispatchability of such plants where thermal energy storage may offer a solution to address the issue. This paper presents a mathematical model for performance prediction of a honeycomb sensible-heat thermal energy storage designed for application of concentrated solar power microturbine. The focus in the model is to consider the laminar developing boundary layers at the entry of the flow channels, which could have a profound effect on the heat-transfer coefficient due to large velocity and temperature gradients, an effect which has not been considered in the modelling of such storage systems. Analysing the thermal and hydrodynamic boundary layer development, the Nusselt number and the friction factor were evaluated using a validated conjugate heat-transfer method. The simulations results were used to develop accurate regression functions for Nusselt number and friction factor. These formulations have been adopted within a one-dimensional model to evaluate the performance of the storage under different operating conditions. The model was in good agreement with conjugate heat transfer results with maximum relative error below 2%. Two case studies are presented to demonstrate the applicability of the proposed methodology. Full article
(This article belongs to the Section Energy Storage and Application)
Show Figures

Figure 1

Open AccessArticle
An Index of Aquiclude Destabilization for Mining-Induced Roof Water Inrush Forecasting: A Case Study
Water 2019, 11(10), 2170; https://doi.org/10.3390/w11102170 (registering DOI) - 18 Oct 2019
Abstract
Aquiclude plays a critical role in the occurrence of mining-induced roof water inrush in underground coal mines. This paper proposes an assessment index for the evaluation of aquiclude stability and a threshold value of water inrush from the roof, based on a case [...] Read more.
Aquiclude plays a critical role in the occurrence of mining-induced roof water inrush in underground coal mines. This paper proposes an assessment index for the evaluation of aquiclude stability and a threshold value of water inrush from the roof, based on a case study of roof water inrush accidents in Cuimu coal mine, China. The relation between roof water inrush and water level variation in the aquifer, and the characteristics of aquiclude deformation, were studied in this assessment. Using the developed assessment criteria, the likelihood of roof water inrush was categorized into different risk levels, which were followed by a proposal for roof water inrush control measures. The main findings of this study are: a) in Cuimu coal mine, the waterbody in the bed separation between the upper aquifer and the aquiclude directly causes the inrush, and inrush occurs after the water level declines in the aquifer; b) tension-induced horizontal strains of aquiclude can be regarded as the index to evaluate the stability of aquiclude affected by underground coal mining—roof water inrush occurs when the maximum horizontal strain reaches a threshold of 10mm/m—c) based on the critical mining height for aquiclude instability, and the different thicknesses of barrier layers, high-risk zones are identified and inrush controls are proposed. Full article
(This article belongs to the Section Water Resources Management and Governance)
Show Figures

Figure 1

Open AccessArticle
Quantification of Modelling Uncertainties in Bridge Scour Risk Assessment under Multiple Flood Events
Geosciences 2019, 9(10), 445; https://doi.org/10.3390/geosciences9100445 (registering DOI) - 18 Oct 2019
Abstract
Local scour is a dynamic process evolving during the lifetime of bridges as a result of the changes in hydrologic and hydraulic conditions. Current approaches for scour risk assessment are generally based on the evaluation of the equilibrium scour depth for a flood [...] Read more.
Local scour is a dynamic process evolving during the lifetime of bridges as a result of the changes in hydrologic and hydraulic conditions. Current approaches for scour risk assessment are generally based on the evaluation of the equilibrium scour depth for a flood event with a prefixed return period. The temporal evolution of the bridge-pier scour process is usually disregarded, by assuming that equilibrium conditions are always attained, regardless of the flood properties. However, recent studies have highlighted the importance of accounting for the contribution of multiple flood events and their exact hydrograph shape. This study aims at quantifying the epistemic uncertainty related to the modelling of the temporal evolution of scour under multiple consecutive flood events in clear-water conditions. A simple numerical case study is considered, using a Markovian framework to describe probabilistically the progression of scour. Well-known time-dependent scour models are used to estimate the temporal evolution of the scour-depth under each flood hydrograph, and the scour estimates are compared with those obtained using widely employed equilibrium scour formulas. Results show that the expected scour depth is influenced by the parameters used to describe the flood hydrograph and that the probability distribution of the scour depth is highly sensitive to the choice of the time-dependent scour model. The uncertainty in the scour estimation stemming from the formula adopted in this study for describing the temporal evolution of the scour depth can be higher than those related to the formula adopted for equilibrium scour. Full article
(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)
Show Figures

Figure 1

Open AccessFeature PaperArticle
Do No Harm: Efficacy of a Single Herbicide Application to Control an Invasive Shrub While Minimizing Collateral Damage to Native Species
Plants 2019, 8(10), 426; https://doi.org/10.3390/plants8100426 (registering DOI) - 18 Oct 2019
Abstract
Control of invasive exotic species in restorations without compromising the native plant community is a challenge. Efficacy of exotic species control needs to consider collateral effects on the associated plant community. We asked (1) if short-term control of a dominant exotic invasive, Lespedeza [...] Read more.
Control of invasive exotic species in restorations without compromising the native plant community is a challenge. Efficacy of exotic species control needs to consider collateral effects on the associated plant community. We asked (1) if short-term control of a dominant exotic invasive, Lespedeza cuneata in grassland restorations allows establishment of a more diverse native plant community, and (2) if control of the exotic and supplemental seed addition allows establishment of native species. A manipulative experiment tested the effects of herbicide treatments (five triclopyr and fluroxypyr formulations plus an untreated control) and seed addition (and unseeded control) on taxonomic and phylogenetic diversity, and community composition of restored grasslands in three sites over three years. We assessed response of L. cuneata through stem density counts, and response of the plant community through estimates of canopy cover. Herbicide treatments reduced the abundance of the exotic in the first field season leading to a less dispersed community composition compared with untreated controls, with the exotic regaining dominance by the third year. Supplemental seed addition did not provide extra resistance of the native community to reinvasion of the exotic. The communities were phylogenetically over-dispersed, but there was a short-term shift to lower phylogenetic diversity in response to herbicides consistent with a decrease in biotic filtering. Native plant communities in these grassland restorations were resilient to short-term reduction in abundance of a dominant invasive even though it was insufficient to provide an establishment window for native species establishment. Full article
(This article belongs to the Special Issue Invasive Plants)
Show Figures

Figure 1

Open AccessFeature PaperArticle
Effects of a Dynamic Injection Flow Rate on Slug Generation in a Cross-Junction Square Microchannel
Processes 2019, 7(10), 765; https://doi.org/10.3390/pr7100765 (registering DOI) - 18 Oct 2019
Abstract
The injection flow rates of two liquid phases play a decisive role in the slug generation of the liquid-liquid slug flow. However, most injection flow rates so far have been constant. In order to investigate the effects of dynamic injection flow rates on [...] Read more.
The injection flow rates of two liquid phases play a decisive role in the slug generation of the liquid-liquid slug flow. However, most injection flow rates so far have been constant. In order to investigate the effects of dynamic injection flow rates on the slug generation, including the slug size, separation distance and slug generation cycle time, a transient numerical model of a cross-junction square microchannel is established. The Volume of Fluid method is adopted to simulate the interface between two phases, i.e., butanol and water. The model is validated by experiments at a constant injection flow rate. Three different types of dynamic injection flow rates are applied for butanol, which are triangle, rectangular and sine wave flow rates. The dynamic injection flow rate cycles, which are related to the constant slug generation cycle time t0, are investigated. Results show that when the cycle of the disperse phase flow rate is larger than t0, the slug generation changes periodically, and the period is influenced by the cycle of the disperse phase flow rate. Among the three kinds of dynamic disperse flow rate, the rectangular wave influences the slug size most significantly, while the triangle wave influences the separation distance and the slug generation time more prominently. Full article
(This article belongs to the Special Issue Smart Flow Control Processes in Micro Scale)
Show Figures

Figure 1

Open AccessArticle
Apalutamide Sensitizes Prostate Cancer to Ionizing Radiation via Inhibition of Non-Homologous End-Joining DNA Repair
Cancers 2019, 11(10), 1593; https://doi.org/10.3390/cancers11101593 (registering DOI) - 18 Oct 2019
Abstract
Androgen-deprivation therapy was shown to improve treatment outcome of external beam radiation therapy (EBRT) for locally advanced prostate cancer (PCa). DNA damage response (DDR) was suggested to play a role in the underlying mechanism, but conflicting results were reported. This study aims to [...] Read more.
Androgen-deprivation therapy was shown to improve treatment outcome of external beam radiation therapy (EBRT) for locally advanced prostate cancer (PCa). DNA damage response (DDR) was suggested to play a role in the underlying mechanism, but conflicting results were reported. This study aims to reveal the role of the androgen receptor (AR) in EBRT-induced DDR and to investigate whether next-generation AR inhibitor apalutamide can radiosensitize PCa. PCa cell lines and tissue slices were treated with anti-androgen alone or combined with EBRT. The effect of treatments on cell growth, tissue viability, DDR, and cell cycle were investigated. RAD51 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) levels were determined by Western blotting. Homologous recombination (HR) capacity was measured with the directed repeats-green fluorescent protein (DR-GFP) assay. We report the radiosensitizing effect of anti-androgens, which showed synergism in combination with EBRT in AR-expressing tumor slices and cell lines. Moreover, a compromised DDR was observed in AR-expressing cells upon AR suppression. We found that AR inhibition downregulated DNA-PKcs expression, resulting in reduced non-homologous end-joining repair. DDR through HR was a secondary effect due to cell-cycle change. These data provide a mechanistic explanation for the combination regimen and support the clinical use of apalutamide together with EBRT for localized PCa patients. Full article
Show Figures

Figure 1

Open AccessFeature PaperArticle
LC-ESI-QTOF/MS Profiling of Australian Mango Peel By-Product Polyphenols and Their Potential Antioxidant Activities
Processes 2019, 7(10), 764; https://doi.org/10.3390/pr7100764 (registering DOI) - 18 Oct 2019
Abstract
Mango (Mangifera indica L.) is one of the most important fruits in the world. Mango peel is an important by-product that is rich in polyphenols and it could have high economic value if it is effectively utilized. Phenolic characterization is an essential [...] Read more.
Mango (Mangifera indica L.) is one of the most important fruits in the world. Mango peel is an important by-product that is rich in polyphenols and it could have high economic value if it is effectively utilized. Phenolic characterization is an essential step in the commercial utilization of mango peel by-products as food ingredients. Herein, qualitative and quantitative analyses of two Australian mango peel “Keitt” and “Kensington Pride” (K&P) by-products were conducted while using liquid chromatography coupled to electrospray ionisation and quadrupole time of flight mass spectrometry (LC-ESI-QTOF/MS) and high-performance liquid chromatography coupled to photodiode array detector (HPLC-PDA). A total of 98 polyphenols compounds were tentatively identified in both Keitt peel and K&P peel extracts, with greater concentrations of these compounds being detected in Keitt peel. The total phenolic content (TPC), total flavonoid content (TFC), and a total tannin content (TTC) were determined. The antioxidant activity of mango peel by-products was determined while using 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant assay, ferric reducing antioxidant power (FRAP) assay, and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay. Keitt peel contained higher concentrations of total phenolic compounds, flavonoids, and tannins and had higher antioxidant capacity in DPPH, FRAP, and ABTS assays as compared to K&P peel. In HPLC-PDA quantification, the predominant phenolic compounds in Keitt peel and K&P peel were catechin (62.32 ± 0.01 mg/gd.w.) and syringic acid (17.78 ± 0.01 mg/gd.w). Full article
(This article belongs to the Special Issue Screening of Bioactive Compounds from Food Processing Waste)
Show Figures

Graphical abstract

Open AccessArticle
The Fragment-Based Development of a Benzofuran Hit as a New Class of Escherichia coli DsbA Inhibitors
Molecules 2019, 24(20), 3756; https://doi.org/10.3390/molecules24203756 (registering DOI) - 18 Oct 2019
Abstract
A fragment-based drug discovery approach was taken to target the thiol-disulfide oxidoreductase enzyme DsbA from Escherichia coli (EcDsbA). This enzyme is critical for the correct folding of virulence factors in many pathogenic Gram-negative bacteria, and small molecule inhibitors can potentially be [...] Read more.
A fragment-based drug discovery approach was taken to target the thiol-disulfide oxidoreductase enzyme DsbA from Escherichia coli (EcDsbA). This enzyme is critical for the correct folding of virulence factors in many pathogenic Gram-negative bacteria, and small molecule inhibitors can potentially be developed as anti-virulence compounds. Biophysical screening of a library of fragments identified several classes of fragments with affinity to EcDsbA. One hit with high mM affinity, 2-(6-bromobenzofuran-3-yl)acetic acid (6), was chemically elaborated at several positions around the scaffold. X-ray crystal structures of the elaborated analogues showed binding in the hydrophobic binding groove adjacent to the catalytic disulfide bond of EcDsbA. Binding affinity was calculated based on NMR studies and compounds 25 and 28 were identified as the highest affinity binders with dissociation constants (KD) of 326 ± 25 and 341 ± 57 µM respectively. This work suggests the potential to develop benzofuran fragments into a novel class of EcDsbA inhibitors. Full article
(This article belongs to the Special Issue Fragment Based Drug Discovery)
Show Figures

Graphical abstract

Open AccessArticle
Is NO the Answer? The Nitric Oxide Pathway Can Support Bone Morphogenetic Protein 2 Mediated Signaling
Cells 2019, 8(10), 1273; https://doi.org/10.3390/cells8101273 (registering DOI) - 18 Oct 2019
Abstract
The growth factor bone morphogenetic protein 2 (BMP2) plays an important role in bone development and repair. Despite the positive effects of BMP2 in fracture healing, its use is associated with negative side effects and poor cost effectiveness, partly due to the large [...] Read more.
The growth factor bone morphogenetic protein 2 (BMP2) plays an important role in bone development and repair. Despite the positive effects of BMP2 in fracture healing, its use is associated with negative side effects and poor cost effectiveness, partly due to the large amounts of BMP2 applied. Therefore, reduction of BMP2 amounts while maintaining efficacy is of clinical importance. As nitric oxide (NO) signaling plays a role in bone fracture healing and an association with the BMP2 pathway has been indicated, this study aimed to investigate the relationship of BMP2 and NO pathways and whether NO can enhance BMP2-induced signaling and osteogenic abilities in vitro. To achieve this, the stable BMP reporter cell line C2C12BRELuc was used to quantify BMP signaling, and alkaline phosphatase (ALP) activity and gene expression were used to quantify osteogenic potency. C2C12BRELuc cells were treated with recombinant BMP2 in combination with NO donors and substrate (Deta NONOate, SNAP & L-Arginine), NOS inhibitor (LNAME), soluble guanylyl cyclase (sGC) inhibitor (LY83583) and activator (YC-1), BMP type-I receptor inhibitor (LDN-193189), or protein kinase A (PKA) inhibitor (H89). It was found that the NOS enzyme, direct NO application, and sGC enhanced BMP2 signaling and improved BMP2 induced osteogenic activity. The application of a PKA inhibitor demonstrated that BMP2 signaling is enhanced by the NO pathway via PKA, underlining the capability of BMP2 in activating the NO pathway. Collectively, this study proves the ability of the NO pathway to enhance BMP2 signaling. Full article
(This article belongs to the Special Issue TGF-beta/BMP Signaling Pathway)
Show Figures

Graphical abstract

Open AccessFeature PaperArticle
Energetic Analysis of Different Configurations of Power Plants Connected to Liquid Chemical Looping Gasification
Processes 2019, 7(10), 763; https://doi.org/10.3390/pr7100763 (registering DOI) - 18 Oct 2019
Abstract
In this article, a thermodynamic study was conducted on the energetic and exergy performance of a new configuration of liquid chemical looping gasification (LCLG) plant integrated with a power block to assess the overall performance of the system including exergy partitioned in syngas [...] Read more.
In this article, a thermodynamic study was conducted on the energetic and exergy performance of a new configuration of liquid chemical looping gasification (LCLG) plant integrated with a power block to assess the overall performance of the system including exergy partitioned in syngas and first law efficiency (FLE). LCLG is a relatively new concept for the production of high-quality synthetic gas from solid feedstock such as biomass. As the temperature and pressure of the looping system are high, there is thermodynamic potential to co-produce chemical products, power and heat. Hence, in the present work, three different configurations of a power cycle were thermodynamically assessed. In the first proposed power cycle, the produced syngas from the gasifier was combusted in a combustion chamber and the exhausted gases were fed into a gas turbine. In the second and third proposed power cycles, the hot air was directly fed into a gas turbine or was used to produce steam for the steam turbine combined cycle. The processes were simulated with Aspen Plus and Outotec HSC chemistry software packages. The influence of different operating parameters including temperature and pressure of the air reactor and type of oxygen carrier on the first law and exergy efficiency (exergy partitioned in synthetic gas) was assessed. Results showed that the FLE for the proposed gas turbine and steam turbine combined cycles was ~33% to 35%, which is within the range of the efficiency obtained for the state-of-the-art power cycles reported in the literature. Results also showed that lead oxide was a suitable oxygen carrier for the LCLG system, which can be integrated into a steam turbine combined cycle with an FLE of 0.45, while copper oxide showed an FLE of 0.43 for the gas turbine combined cycle. Full article
(This article belongs to the Special Issue Thermodynamics: Modeling and Simulation)
Show Figures

Figure 1

Open AccessFeature PaperReview
Targeting Programmed Fusobacterium nucleatum Fap2 for Colorectal Cancer Therapy
Cancers 2019, 11(10), 1592; https://doi.org/10.3390/cancers11101592 (registering DOI) - 18 Oct 2019
Abstract
Colorectal patients generally have the maximum counts of Fusobacterium nucleatum (F. nucleatum) in tumors and elevate colorectal adenomas and carcinomas, which show the lowest rate of human survival. Hence, F. nucleatum is a diagnostic marker of colorectal cancer (CRC). Studies demonstrated that targeting [...] Read more.
Colorectal patients generally have the maximum counts of Fusobacterium nucleatum (F. nucleatum) in tumors and elevate colorectal adenomas and carcinomas, which show the lowest rate of human survival. Hence, F. nucleatum is a diagnostic marker of colorectal cancer (CRC). Studies demonstrated that targeting fusobacterial Fap2 or polysaccharide of the host epithelium may decrease fusobacteria count in the CRC. Attenuated F. nucleatum-Fap2 prevents transmembrane signals and inhibits tumorigenesis inducing mechanisms. Hence, in this review, we hypothesized that application of genetically programmed fusobacterium can be skillful and thus reduce fusobacterium in the CRC. Genetically programmed F. nucleatum is a promising antitumor strategy. Full article
(This article belongs to the Special Issue Targeting Therapy for Colon Cancer)
Show Figures

Graphical abstract

Open AccessArticle
On the Icephobic Behavior of Organosilicon-Based Surface Structures Developed Through Atmospheric Pressure Plasma Deposition in Nitrogen Plasma
Coatings 2019, 9(10), 679; https://doi.org/10.3390/coatings9100679 (registering DOI) - 18 Oct 2019
Abstract
In many regions around the world, atmospheric icing during freezing rains and ice storms can cause severe damage to exposed infrastructure. Subsequently, protective coatings capable of ice accumulation prevention or ice adhesion reduction, often referred to as icephobic coatings, have gained a significant [...] Read more.
In many regions around the world, atmospheric icing during freezing rains and ice storms can cause severe damage to exposed infrastructure. Subsequently, protective coatings capable of ice accumulation prevention or ice adhesion reduction, often referred to as icephobic coatings, have gained a significant amount of interest. In this study, we examine an atmospheric-pressure plasma jet technique for the development of organosilicon-based icephobic coatings on aluminum substrates. Initially, Al-6061 samples are exposed to multiple passes of air plasma treatment at very short jet-to-substrate distances to create a microporous alumina-based surface structure. These surfaces are then used for plasma deposition of superhydrophobic coatings in the same jet with hexamethyldisiloxane (HMDSO) as the precursor and nitrogen as the plasma gas. Several samples are created with varying plasma precursor flow rates and number of deposition passes. All samples are exposed to three cycles of icing/de-icing to estimate coatings’ stability in aggressive natural conditions. The effects of multiple icing/de-icing cycles on surface chemistry, surface morphology, and wetting behavior is studied. It is shown that the most remarkable mechanism through which icing affects surface properties is coating removal during aggressive de-icing procedure. Finally, the icephobic properties of the most efficient coating (referred to as PT5x3) is further studied through 10 cycles of icing/de-icing, and it is shown that this coating can reduce ice adhesion strength by a factor of at least two for up to nine cycles of icing/de-icing. Full article
(This article belongs to the Special Issue Surface Plasma Treatments)
Show Figures

Figure 1

Open AccessArticle
Validation of a HILIC UHPLC-MS/MS Method for Amino Acid Profiling in Triticum Species Wheat Flours
Foods 2019, 8(10), 514; https://doi.org/10.3390/foods8100514 (registering DOI) - 18 Oct 2019
Abstract
Amino acids are essential nutritional components as they occur in foods either in free form or as protein constituents. An ultra-high-performance (UHPLC) hydrophilic liquid chromatography (HILIC)-tandem Mass Spectrometry (MS) method has been developed and validated for the quantification of 17 amino acids (AA) [...] Read more.
Amino acids are essential nutritional components as they occur in foods either in free form or as protein constituents. An ultra-high-performance (UHPLC) hydrophilic liquid chromatography (HILIC)-tandem Mass Spectrometry (MS) method has been developed and validated for the quantification of 17 amino acids (AA) in wheat flour samples after acid hydrolysis with 6 M HCl in the presence of 4% (v/v) thioglycolic acid as a reducing agent. The developed method proved to be a fast and reliable tool for acquiring information on the AA profile of cereal flours. The method has been applied and tested in 10 flour samples of spelt, emmer, and common wheat flours of organic or conventional cultivation and with different extraction rates (70%, 90%, and 100%). All the aforementioned allowed us to study and evaluate the variation of the AA profile among the studied flours, in relation to other quality characteristics, such as protein content, wet gluten, and gluten index. Significant differences were observed in the AA profiles of the studied flours. Moreover, AA profiles exhibited significant interactions with quality characteristics that proved to be affected based mainly on the type of grain. A statistical and multivariate analysis of the AA profiles and quality characteristics has been performed, as to identify potential interactions between protein content, amino acids, and quality characteristics. Full article
(This article belongs to the Special Issue Application of Analytical Chemistry to Foods and Food Technology)
Show Figures

Graphical abstract

Open AccessArticle
Stability of Coinage Metals Interacting with C60
Nanomaterials 2019, 9(10), 1484; https://doi.org/10.3390/nano9101484 (registering DOI) - 18 Oct 2019
Abstract
Buckminsterfullerene (C60) has been advocated as a perfect candidate material for the encapsulation and adsorption of a variety of metals and the resultant metallofullerenes have been considered for the use in different scientific, technological and medical areas. Using spin-polarized density functional [...] Read more.
Buckminsterfullerene (C60) has been advocated as a perfect candidate material for the encapsulation and adsorption of a variety of metals and the resultant metallofullerenes have been considered for the use in different scientific, technological and medical areas. Using spin-polarized density functional theory together with dispersion correction, we examine the stability and electronic structures of endohedral and exohedral complexes formed between coinage metals (Cu, Ag and Au) and both non-defective and defective C60. Encapsulation is exoergic in both forms of C60 and their encapsulation energies are almost the same. Exohedral adsorption of all three metals is stronger than that of endohedral encapsulation in the non-defective C60. Structures and the stability of atoms interacting with an outer surface of a defective C60 are also discussed. As the atoms are stable both inside and outside the C60, the resultant complexes can be of interest in different scientific and medical fields. Furthermore, all complexes exhibit magnetic moments, inferring that they can be used as spintronic materials. Full article
Show Figures

Graphical abstract

Open AccessArticle
Effect of Scanning Speed on the Interface Behavior and Dendrite Growth of Laser Remelted Fe-Based Ni/WC Coatings
Coatings 2019, 9(10), 677; https://doi.org/10.3390/coatings9100677 (registering DOI) - 18 Oct 2019
Abstract
The flame sprayed Fe-based Ni/WC cermet coating was treated by laser remelting. The influence of scanning speeds on the interface behaviour was investigated. SEM, XRD and EDS were used to analyse the microstructure, phase composition and element distribution of the interface. The results [...] Read more.
The flame sprayed Fe-based Ni/WC cermet coating was treated by laser remelting. The influence of scanning speeds on the interface behaviour was investigated. SEM, XRD and EDS were used to analyse the microstructure, phase composition and element distribution of the interface. The results showed that the interface of the coating contained holes and interlayer cracks and showed typical mechanical bonding features. The coatings mainly consisted of [Fe, Ni], Cr, WC, Cr7C3, Fe0.04Ni0.36, and other phases. After laser remelting, the coatings were smooth and dense due to the existence of well-developed dendrite structures and metallurgical bonding and could reach the optimal performance at 200 mm/s. New phases such as Fe2Si, Cr2Si, and W2C appeared in the remelted layers. With the increase of scanning speed, the half-peak height and average grain size became wider and smaller. At the same time, the measured dendrite spacing decreased with increasing scanning speed. Full article
(This article belongs to the Special Issue Laser Surface Modification of Metallic Materials)
Show Figures

Figure 1

Open Access Journals

Browse by Indexing Browse by Subject Selected Journals
Back to TopTop