Uncoated Plates Research Articles

IMPROVING THE PERFORMANCE OF ZNO NANOPARTICLES FOR EOR IN HIGH-TEMPERATURE AND HIGH SALINITY CARBONATE RESERVOIRS

The main challenge of the application of nanofluids for enhanced oil recovery (EOR) in carbonate reservoirs is to maintain colloidal stability under reservoir conditions with high salinity and high temperature. In this study, we address this issue by increasing the stability and hydrophilicity of ZnO nanoparticles by adding TTIP. Adding TTIP on the surface of ZnO nanoparticles results in an increase in the hydrophilic heads in the final product. Then, these nanoparticles are used to coat carbonate rock surfaces to change their wettability. The coated rock plates are obtained by aging them in nanofluids. The modified ZnO-based coatings show to be more effective for wettability alteration purposes compared to the conventional ZnO coating. The un-coated rock plate is strongly oil-wet, where the water and n-heptane droplets contact angles on this surface are 168° and 0°, respectively. After aging the rock samples in nanofluids, superhydrophilic coatings form on the superhydrophobic surfaces. The rock surface before and after treatment, as well as the synthesized nanoparticles, are characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses. Results of this study indicate the possibility of using the materials for wettability alteration of oil-wet carbonate rock in the EOR process. The results of core flooding tests demonstrate that the oil recovery enhances significantly through the nanofluid flooding.

Fire Behavior and Adhesion of Magnesium Phosphate Coatings for the Protection of Steel Structures

This paper presents the main properties of magnesium phosphate cements (MPCs) to be used as coatings for passive fire protection of steel structures. The influence of various additions, i.e., waste glass powder, fly ash, a styrene–acrylic dispersion, and expandable graphite, on the fire behavior and the adhesion to steel substrates of magnesium phosphate coatings is presented in this paper. The setting time of studied cements is extended when magnesia, the main component of MPCs, is partially replaced with fly ash or/and waste glass powder. The mineralogical composition of these cements, before and after thermal treatment at 1050 °C, was assessed by X-ray diffraction and could explain the changes in compressive strength, volume, and mass recorded for the thermally treated specimens. The studied magnesium phosphate coatings have a good adherence to the steel substrate (assessed by a pull-off test) both before and after direct contact with a flame (fire test) and decrease the temperature of the steel substrate by 30% with respect to the one recorded for the uncoated steel plate.

Topographical and Ultrastructural Evaluation of Titanium Plates Coated with PLGA, Chitosan, and/or Meropenem: An In Vitro Study.

The present investigation was undertaken to evaluate the topographical and ultrastructural architecture of titanium plates coated with polylactic co-glycolic acid (PLGA), chitosan (CH), and/or meropenem (MEM) with or without Staphylococcus aureus (SA) or Pseudomonas aeruginosa (PA) bacteria. Single-hole segments of 0.4 mm thick, low-profile titanium plates were spray coated using an airbrush with polymeric carriers (PLGA or CH) loaded with MEM, in addition to the negative control group (uncoated titanium plates). The coated plates and the negative control group were subjected to bacterial biofilms through a cultivation process while being slowly stirred at 20 rpm for 24 h. The samples were fixed and processed for scanning electron microscopic study at 5, 10, and 20 k magnification. The data were statistically analyzed to compare within and between the different materials. Coating titanium plates with PLGA or CH with MEM appeared to enhance bacterial inhibition over uncoated plates, hindering biofilm formation and preventing bacterial proliferation. In the staphylococcus aureus group, the highest bacterial count was observed in the uncoated plates, whereas the lowest count was detected in meropenem-PLGA, followed by PLGA, chitosan, meropenem, and meropenem-chitosan, respectively. On the other hand, the Pseudomonas aeruginosa group with the uncoated plates had the highest bacterial count, whereas the lowest bacterial count was found related to CH, followed by PLGA, MP, MC, and MEM, respectively.

Pleiotropic Effects of Hydroxyurea on Red Blood Cell and Neutrophil Phenotype in Patients with Sickle Cell Disease; Data from the Notice Study

Introduction The pathophysiology of sickle cell disease (SCD) is complex and goes beyond red blood cell (RBC) sickling alone. Neutrophils have been proposed to play an important role in SCD pathophysiology, but their exact contribution remains to be elucidated. Factors such as chronic hemolysis and oxidative stress can influence neutrophil adhesion, activity and aging. We designed a prospective study (Notice) to investigate a broad set of neutrophil characteristics in SCD patients. To correlate treatment effects of hydroxyurea (HU) on neutrophils with those on RBCs in SCD, we also studied RBC sickling and adhesion. Here, we will focus on the effects of hydroxyurea on RBC deformability and neutrophil adhesion, activity and aging. Aim: To assess the effects of HU on RBC deformability and neutrophil phenotypes with respect to adhesion, activation and aging. Methods Blood (EDTA) was collected from SCD patients with HbSS or HbSβ0 in steady-state. A subgroup of patients was included before and during treatment with HU. For measurement of antigen expression by flow cytometry, total leukocyte fraction after lysis of red blood cells (without Percoll gradient) was used and neutrophils were gated based on their forward and side scatter. For in vitro neutrophil adhesion, neutrophils were isolated using a Percoll gradient and lysis buffer, as previously described. (Kuijpers et al. Blood 2007) Neutrophils were labeled with calcein and placed in an uncoated 96-well MaxiSorp plate. After washing, adherent cells were lysed and fluorescence was measured. (Kuijpers et al. J Allergy Clin Immunol 2017). Adhesion of RBCs was measured by flowing whole blood (20x106/ml)over laminin-coated Ibidi slides for 30 minutes with visualization by microscope. Percentage of mean RBC adhesion was normalized to a healthy control (HC). Data were analyzed using SPSS and GraphPad Prism and are presented as mean ±SE or ±SD as appropriate. Conventional statistics were used. Results A total of 49 patients (median age 25.0 (IQR 20.0 - 32.5) years, 39% female) were included. Twenty patients (41%) used a stable dose of HU at baseline. In 10 patients, blood was drawn before and after starting HU treatment. HU treatment improved hemoglobin F and markers of hemolysis and was associated with a decrease in the point of sickling (PoS) of RBCs (from median 24.8 mmHg [IQR 16.0-28.2] to 16.8 [15.0-20.8], P=0.13). Adhesion of RBC was more than 3-fold higher in SCD patients than in HC. At baseline, there was no difference in RBC adhesion between patients with and without HU (P=0.86). After starting HU treatment, RBC adhesion decreased significantly from a median of 318% (normalized to control) to 149% (P=0.016, Figure 1a-b). Adhesion of neutrophils was significantly higher in patients compared to HC (median 18.3% versus 12.6% P <0.0001). No difference was observed between patients with and without HU at baseline. Neutrophil adhesion did not decrease after starting HU treatment (Figure 1c-d). Neutrophil surface expression of CD11b/CD18 was measured as markers of adhesion. While CD11b expression was comparable between SCD patients and HC, CD18 expression was significantly higher in SCD patients (mean MFI 12193 vs 10586, P=0.016; Figure 2b. After treatment with HU both CD11b and CD18 expression decreased, though the differences did not reach statistical significance (P=0.22 and 0.56, respectively). Neutrophils of SCD patients displayed a more aged phenotype compared to neutrophils of HC with lower L-selectin (median MFI 3108 vs 4656, P=0.021) and higher CXCR4 (median MFI 1150 vs 886, P=0.003) expression. Activation marker CD64 was also higher in SCD patients compared to HC (median MFI 1841 vs 1065, P=0.0006). HU treatment seemed to modify all markers more towards a HC phenotype although no statistically significant changes were observed. Conclusion Adhesion of both RBCs and neutrophils is increased in SCD patients compared to HC. HU treatment was associated with significantly improved RBC rheology as shown by decreased PoS and decreased adhesion to laminin. Despite a trend to improvement in expression of adhesion markers (CD11b/CD18), in vitro adhesion of neutrophils did not decrease. These findings could be due to the small sample size of patients starting with HU or by a difference in vitro behaviour of changed composition of neutrophil populations after treatment. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Effect of Zinc Aluminum Magnesium Coating on Spot-Welding Joint Properties of HC340LAD + ZM Steel

Zn-Al-Mg (zinc, aluminum and magnesium)-coated steel is gradually replacing traditional hot-dip galvanized steel due to its excellent corrosion resistance, self-healing properties and good surface hardness. However, the effect of Zn-Al-Mg coating on the resistance spot-welding joint properties of HC340LAD + ZM steel plates is not clear, and there are few systematic studies on it. In this paper, L16 (43) orthogonal experiments were designed on Zn-Al-Mg-coated steel HC340LAD + ZM (thickness = 1 mm). In addition, taking the tensile shear force as the main evaluation standard, the optimal spot-welding process properties could be achieved when the welding current, the welding time and the electrode loading were 10 kA, 14 cycles and 2.6 kN, respectively. On this basis, the formation mechanism, microstructure and corrosion properties of two plates of steels, with or without zinc, aluminum and magnesium coating under different welding times, were studied. The presence of Zn-Al-Mg coating slightly affected the mechanical properties of welding joints. However, the corrosion current of the body material containing Zn-Al-Mg plating was 7.17 times that of the uncoated plate.

Study on anti-corrosion performance of silica fume modified magnesium potassium phosphate cement-based coating on steel

In order to explore the anti-corrosion performance of magnesium potassium phosphate cement (MKPC) coating on steel, and the effect of silica fume with different contents on anti-corrosion ability of MKPC coating, electrochemical tests on the uncoated steel plate sample, MKPC coating sample, and silica fume modified MKPC coating samples were carried out in 3.5% sodium chloride solution. The micromorphology and phase composition of MKPC coating sample and silicon fume modified MKPC coating sample were studied by SEM-EDS and XRD tests, as well as the anti-corrosion mechanism. The results show that MKPC-based anti-corrosion coating has good anti-corrosion effect. After the modification of silica fume, the anti-corrosion ability of MKPC coating is greatly improved, when the content of silica fume is 20% of the mass of the magnesium oxide in the gelling system, the corrosion resistance of the coating is optimal.

A study on biological properties of titanium implants coated with multisubstituted hydroxyapatite

In this work, it was found that the composition of hydroxyapatite coatings deposited on a titanium substrate depends on the temperature of detonation products and on the composition of the initial explosive mixture. Depending on the detonation mode, it was possible to obtain a coating of oxyhydroxyapatite containing or not containing an admixture of other calcium orthophosphates. It was shown for the first time that the structure of multisubstituted Zn–Si-hydroxyapatite and Ag–Zn–Si-hydroxyapatite with substitution degree x(Zn) = x(Si) = 0.2 and x(Ag) = 0.1 has lower thermal stability as compared to unsubstituted hydroxyapatite. The formation of a small amount of the α-Ca3(PO4)2 phase upon detonation deposition of the multisubstituted hydroxyapatites was obviously due to structural transformations that occurred when the material was heated by the detonation products. In vivo biological testing of titanium implants coated or not coated with hydroxyapatite revealed that the coating significantly accelerates osteogenesis in the gap between native bone and the implant; this acceleration improved implant fixation. In animals with the uncoated plates, fibrogenesis processes significantly outstripped the osteogenesis. The presence of Zn and Si ions in the apatite coating had a potentiating influence on the osteoinduction caused by hydroxyapatite. Osteogenesis in this case was more complete and characterized by pronounced processes of mineralization of the bone plates. The addition of Ag ions to the Zn–Si-hydroxyapatite at a concentration of 1 at.% did not impair its osteogenic activity and did not have a toxic effect on bone tissue, while imparting antibacterial properties to the material.

Towards Uncoated Stainless-Steel Bipolar Plates in Automotive PEM Fuel Cells

Bipolar plates (BPPs) have been identified as a key component in improving the economic viability of proton exchange membrane fuel cells (PEMFCs), as they contribute approximately 80 % of weight and 30 % of total cost in a fuel cell stack [1]. Stainless steel is considered an excellent material for mass-producing BPPs with complex flow field structures in a cost-effective manner. However, the perceived risk of corrosion and subsequent metal ion contamination as well as the inherently high contact resistance of stainless-steel surfaces have compelled manufacturers to add protective coatings to BPPs.In this study, we show new insights into the actual metal ion dissolution mechanisms in operating fuel cell systems and present experimental results which demonstrate that stainless-steel bipolar plates can be used in real life fuel cell applications without protective coatings. The bipolar plates were evaluated, in an operating fuel cell, using a dynamic load cycling protocol based on the New European Drive Cycle with increased humidity levels which simulates realistic conditions known to facilitate metal ion dissolution mechanisms [2]. The post analysis showed no signs of surface dissolution on any of the tested bipolar plates which had been subjected to the endurance/stress hybrid tests. Furthermore, only trace amounts of critical metals were found in the MEAs after testing, i.e., an order of magnitude below the radical scavenger (Mn) concentration. The trace metal contamination was comparable to a reference test without bipolar plates (graphite current collector), rendering metal input from the balance of plant the most likely source of contamination. The observable changes in cell performance and voltage degradation was unrelated to the presence of bipolar plates. A selection of experimental data is shown in Figure 1.As a theoretical explanation for the apparent stability of bare stainless-steel plates, three inter-linked phenomena were identified, akin to a three line of defence model [3]. The first and arguably most important of these phenomena is ionic decoupling between electrode and bipolar plate surface. The gas diffusion layer (GDL) strongly inhibits transport of ions from the electrode to the bipolar plate, which leads to a largely unpolarized bipolar plate and a stable surface potential even during load changes of the fuel cell. These stable potentials at the anode and cathode bipolar plates are only influenced by the immediate surroundings of the plate surfaces and are generally much milder than the encountered potentials at the electrodes. Secondly, metal dissolution from the surface of stainless steel follows a passive-transpassive-passive pattern. This mechanism describes a dissolution process, where a change in conditions at the surface, which destabilizes a previously established passive film, will only lead to limited amounts of (transpassive) metal dissolution, until a new stable passive film of different structure establishes itself. Finally, an operating regime which mitigates start/stop effects and hydrogen starvation during load changes will ensure very stable conditions at the bipolar plates’ surfaces, which strongly mitigates the risk of transpassive dissolution. As a final demonstration of the industrial feasibility of uncoated stainless-steel plates, an experimental alloy was tested under the same conditions. Results showed similar resistance to metal dissolution paired with low contact resistance at the level of C-coated or graphite plates. These results help to legitimize the efforts to industrialize uncoated stainless-steel plates since only the contact resistance challenge remains.[1] B. Pollet, S. Kocha, I. Staffell, ”Current status of automotive fuel cells for sustainable transport,” Current Opinion in Electrochemistry, vol. 16, pp. 90-95, 2019[2] T. Novalin, B. Eriksson, S. Proch, U. Bexell, C. Moffatt, J. Westlinder, C. Lagergren, G. Lindbergh, R. Wreland Lindström, “Trace-metal contamination in proton exchange membrane fuel cells caused by laser-cutting stains on carbon-coated metallic bipolar plates,” Int. J. Hydrogen Energy, Volume 46, Issue 26, 2021[3] T. Novalin, B. Eriksson, S. Proch, U. Bexell, C. Moffatt, J. Westlinder, C. Lagergren, G. Lindbergh, R. Wreland Lindström, “Concepts for preventing metal dissolution from stainless-steel bipolar plates in PEM fuel cells,” Energy Conversion and Management, 2022 Figure 1

Permeability of Olmesartan Medoxomil from Lipid Based and Suspension Formulations using an Optimized HDM-PAMPA Model

Hexadecane membrane-parallel artificial membrane permeability assay (HDM-PAMPA) is based on an artificial hexadecane membrane that separates the two compartments (donor and acceptor compartment). This model is used to predict the permeability of drugs in gastrointestinal tract and to simulate the passive absorption. In vivo behaviour of the drugs can be estimated with these systems in drug development studies. In our study we optimized HDM-PAMPA model to determine permeability of olmesartan medoxomil (OM) lipid based drug delivery system (OM-LBDDS). In order to prove that LBDDS formulation facilitates the weak permeability of OM, permeation rates were compared with the OM suspension formula (containing 0.25% v/w CMC). The experiment was performed on a 96-well MultiScreen® PAMPA filter plate (MAIPN4510). The permeability of olmesartan formulations from the donor to acceptor compartment separated by a HDM membrane were determined by the previous validated HPLC method. We created positive control series without coating hexadecane membrane to present the LBDDS and suspension formulation permeability from uncoated plates. The effective permeability constant (Pe) was calculated by the formula and improvement of permeability of OM-LBDDS formulation from hexadecane membrane was confirmed. On the contrary there was no permeation of OM-Suspension in the hexadecane coated plates. As a result, the intestinal permeability of OM-LBDDS was calculated to be at least 100 times more than the suspension. OM-Suspension permeation was only observed in the hexadecane uncoated positive control plates. This was also manifestation of HDM-PAMPA mimicking permeability of intestines because of its lipidic construction.

A GAN-Augmented Corrosion Prediction Model for Uncoated Steel Plates

The deterioration and damage of aging steel structures have caused huge safety concerns. Corrosion has been identified as a big reason for the deterioration and damage, which causes steel members to lose materials. As a result, the structures’ stiffness and load-bearing capacity will be reduced, which brings economic losses and safety hazards. For the maintenance and repair of steel structures, fast and accurate prediction of corrosion development plays a critical role in numerical simulation analysis, which could save time and costs. In this research, we build a simulation system based on GAN data augmentation with UNet as the generator and MobileNetV2 as the discriminator. The goal is to effectively predict the corrosion behavior of uncoated steel structures over time and under different circumstances. The system can simulate three stages of corrosion based on the dataset collected from experiments. It can also predict the corrosion of steel plates in the next stage. The discriminator of the system can be used to classify the type of steel, the stage of corrosion, and days of corrosion. Based on comparative experiments, our system demonstrates outstanding performance and outperforms the baseline model.

Aluminum Leaching from Fluid Warmers: Regulatory Deferral to Clinicians' Decision.

Fluid-warming systems are crucial in surgical and trauma settings because of their key role in preventing or treating hypothermia and enabling proper resuscitation of blood products that are stored cold. Recently, several manufacturers have issued warnings of the possibility of aluminum leaching from their fluid warmers and cautioned about the potential for aluminum toxicity in patients who underwent fluid resuscitation with these devices. Studies suggest that one of the main factors affecting aluminum leaching in this setting is the coating of the aluminum plate itself. Coating, often with a biocompatible material, appears to reduce aluminum leaching by 100- to 200-fold compared with an uncoated plate. Nonetheless, leaching with the coating is still at a level exceeding U.S. regulations. A few aluminum-free warming systems are available on the market, but these are not carried by all providers and some clinicians may be less familiar with their use. Medical device manufacturers will likely design future warming systems with less potential for aluminum blood contact. In the meantime, the risk of inadequate resuscitation, consequent to the proper fluid warmer no longer being available, is contrasted with the risk of potential toxicity. In the situation described here, the regulators deferred the ultimate decision of which fluid warmer to use in a given situation to the risk-benefit decision of the clinician.

Effect of poly-D-lysine on proliferation and senescence of caprine spermatogonial stem cells &lt;em&gt;in vitro&lt;/em&gt;

Spermatogonial stem cells (SSCs) have the unique ability of both self-renewing and to produce progeny that undergoes differentiation to spermatozoa. As SSCs exist in very low numbers, therefore efficient in vitro expansion of SSCs is important prior to their clinical applications. In this study, we tried to improve the functionality of putative SSCs (pSSCs) during culture using poly-D-lysine (PDL) coating. For this, plates were coated with 0.01% PDL with different coating time interim treatments (5, 30 and 60 min) while control remained uncoated. The adequate amount of pSSCs of the goat was isolated and enriched using two-step enzymatic digestion and differential plating methods. Further, the functionality of pSSCs was evaluated by cell growth analysis, cell proliferation, senescence, and the presence of pluripotency (alkaline phosphatase, OCT-4) and SSC related (PGP-9.5) markers. The number and size of pSSCs colonies in 0.01% PDL coating groups were significantly (P <0.05) higher than in the control group. Similarly, pSSCs on uncoated plates expressed significantly (P <0.05) higher

Performance of New Absorber Coating Strategy in Solar Air Heaters: An Experimental Case Study

Asphalt materials commonly have high absorption coefficients, and their surface temperature reaches as high as 80 oC during daytime hours since their surfaces are exposed to solar radiation for long periods. Hence, asphalt pavements can easily be converted to solar air heaters (SAHs) to collect solar energy. Even though asphalt materials have low thermal conductivity, resulting in a weak convection heat exchange rate between the flowing air and asphalt surface. The current experimental study analyzes utilizing aluminum shavings as asphalt coating materials to improve SAHs’ thermal performance. To this aim, a serpentine SAH prototype was constructed, and several sensors were utilized to monitor its dynamic thermal response. Black-painted aluminum shavings were utilized as coating materials to improve the convective heat exchange rate and increase the roughness of the absorber surface. Two scenarios were considered, including the uncoated absorber plate and coated one with 0.2 kg aluminum shavings. The experiments were carried out for two air mass flow rates of 0.02 kg/s and 0.03 kg/s under field conditions. Based on the air mass flow rate, the coated absorber reaches higher temperatures, approximately 5 oC to 9 oC, than the uncoated one. The acquired results illustrate that the coated SAH has nearly 4 oC to 5 oC higher maximum exhaust air temperature; hence, the coating strategy improves the thermal efficiency by 24.75% and 44% in two air mass flow rates of 0.02 kg/s and 0.03 kg/s, respectively.

The Role of Endothelial Superoxide Dismutase 2 in Modulating Sickle Pathology

Sickle cell disease (SCD) patients suffer from hemolysis in microcirculation. On the one hand, hemoglobin and heme released from sickled red blood cells catalyze reactive oxygen species (ROS) generation by Fenton chemistry. On the other hand, sickled red blood cells occlude capillaries, creating a hypoxic condition that exacerbates ROS production. As an essential antioxidant mechanism, superoxide dismutase 2 (SOD2) detoxifies superoxide by converting it to hydrogen peroxide (H 2O 2) in the mitochondria. In SCD patients, despite the elevated ROS production, we found that SOD2 expression is suppressed in the pulmonary endothelium (Figure 1A,B). Therefore, we hypothesize the depletion of endothelial SOD2 compromises endothelial function and exacerbates the progression of SCD.To examine the role of endothelial SOD2, we silenced SOD2 gene expression (SOD2 KD) with siRNA in primary human pulmonary microvascular endothelial cells (hPMVECs). Knocking down SOD2 in hPMVECs accelerated mitochondrial superoxide production and compromised mitochondrial potential. However, mitochondrial respiration, the activity of respiratory complexes, and the cellular ATP content were not affected by SOD2 KD. An important function of endothelial cells is to form a barrier and sequester cellular and molecular contents in the blood. SOD2 KD hPMVECs exhibited increased albumin leakage and decreased transendothelial resistance, indicating a disrupted endothelial barrier(Figure 1C). The defect in the endothelial barrier was rescued by adding 4 mM H 2O 2(Figure 1D), suggesting SOD2-derived H 2O 2 may serve as a critical signaling molecule. Moreover, cell migration or proliferation was inhibited in SOD2 KD hPMVECs, which was examined by a scratch assay.Since both cell migration and barrier maintenance require focal adhesion assembly, we next investigated the role of SOD2 in focal adhesion dynamics. In an attachment assay, SOD2 KD reduced cell attachment rate on uncoated plates, which was blunted by fibronectin precoating, indicating a fibronectin-dependent defect in cell adhesion(Figure 1E,F). Notably, although fibronectin protein expression in hPMVECs was not altered, SOD2 KD decreased the dimer/monomer ratio. Furthermore, confocal images showed that fibronectin was retained in SOD2 KD cells(Figure 1G), highlighting the importance of SOD2 in fibronectin assembly.In conclusion, we demonstrated for the first time that SOD2 expression is diminished in the pulmonary endothelium of SCD patients and that endothelial SOD2 is crucial for endothelial function by facilitating fibronectin assembly. The importance of SOD2 in endothelial function may prove therapeutic value in SCD patients, which requires further investigation. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Interchanging characteristic of plasma spray coating from superhydrophobic to hydrophilic under the applied electric field

ABSTRACT In the current work, by using NiTi plasma spray, superhydrophobic property is developed for compressor parts used in aerospace engine. The durability of the coating enhances in case of droplet impingement in cold condition (temperature = 25 °C). For the hot condition the aforesaid coating needs to become hydrophilic for the retention of high durability characteristic. The discussed switching is achieved by keeping the coating with in an influence of electric field. The results revealed that the surface roughness (12.4 µm) of the coating supports the attainment of superhydrophobic characteristic depicting contact and rolling angle of 164° ± 1.5 and 8° ± 1, respectively at normal condition. By applying electric field, the coating is converted to hydrophilic in hot condition noticed by impact mapping of droplets. Furthermore, it has been observed that the coated steel plate shows better efficiency as compared to uncoated steel plate under electric field.

Evaluation of MC3T3-E1 Cell Osteogenesis in Different Cell Culture Media.

Many biomaterials have been evaluated using cultured cells. In particular, osteoblast-like cells are often used to evaluate the osteocompatibility, hard-tissue-regeneration, osteoconductive, and osteoinductive characteristics of biomaterials. However, the evaluation of biomaterial osteogenesis-inducing capacity using osteoblast-like cells is not standardized; instead, it is performed under laboratory-specific culture conditions with different culture media. However, the effect of different media conditions on bone formation has not been investigated. Here, we aimed to evaluate the osteogenesis of MC3T3-E1 cells, one of the most commonly used osteoblast-like cell lines for osteogenesis evaluation, and assayed cell proliferation, alkaline phosphatase activity, expression of osteoblast markers, and calcification under varying culture media conditions. Furthermore, the various media conditions were tested in uncoated plates and plates coated with collagen type I and poly-L-lysine, highly biocompatible molecules commonly used as pseudobiomaterials. We found that the type of base medium, the presence or absence of vitamin C, and the freshness of the medium may affect biomaterial regeneration. We posit that an in vitro model that recapitulates in vivo bone formation should be established before evaluating biomaterials.

Enhancement of bone to polylactic acid plate bonding by carbonate apatite coating

Polylactic acid (PLA) has no osteoconductivity, causing the early failure of PLA implants. For obviating this problem, coating, rather than incorporation, of PLA with calcium phosphate is considered to be effective. In this study, PLA plates were coated with granular carbonate apatite (CAp), the inorganic component of bone, using the thermal fusion bonding method. The water contact angles of the CAp-coated PLA (CAp/PLA) plates and PLA were 0.7° ± 0.1° and 90.3° ± 3.9°, respectively. Thus, CAp coating significantly improved the wettability of the PLA surface. Furthermore, the roughness (Ra) of CAp/PLA and PLA was 11.7 ± 2.2 μm and 1.8 ± 0.2 μm, respectively. CAp coating involved two types of micropores (~30–80 μm and ~2 μm). Thus, CAp coating provided a rough surface and micropores to the PLA plate. The CAp/PLA and uncoated PLA plates were fixed onto a rabbit tibial surface to evaluate their bone formation and adhesion abilities. Four weeks after implantation, new bone formed on the surface of the CAp/PLA plates. In contrast, no tissue was present in most of the regions between the uncoated PLA plate and the tibia. The tensile bond strengths of the CAp/PLA and PLA plates to the tibia were 4.0 ± 2.5 and 0 N, respectively. Thus, CAp coating of PLA promoted new bone formation on the plate surface and increased the ability to bond to the bone surface at an early stage. CAp coating of PLA is an effective strategy for achieving rapid and robust bone fixation.

Flame resistance of geopolymer foam coatings for the fire protection of steel

This research investigates the fire resistance of novel geopolymer (GP) foams, based on alkali-activated metakaolin and silica fume (SF). Fresh GP foams are applied as coatings on steel plates. After one week curing, the foams are subjected to a flame burn-through test. Changes in their physico-chemical properties are characterized before and after fire test, mainly with XRD, quantitative MAS NMR, electron probe micro-analysis, quantitative X ray micro-computed tomography and heat conductivity. Results show that GP foams are excellent thermal barriers, providing up to 251 °C less than for uncoated steel plate. Their porosity ranges between 25 and 81%, for typical pore sizes d50 from 0.5 to 3.0 mm 29Si MAS NMR shows that the proportion of GP cement only decreases from 60-68% to 53–58% after fire. SF expands and creates small pores in the coating, which is favorable to decrease heat conductivity by a factor of 2 whatever the foam.

Creation of Polymer Coatings for Improving of Protective Properties of Surfaces

In this paper, the preparation of polymer coatings on the surface of metal structural elements is considered to improve their physical, mechanical and strength properties. It is shown that the behavior of substrate samples under mechanical loads can be estimated using mathematical modeling methods. The properties of coatings and the mechanical properties of coated and uncoated metal plates have been evaluated. Methods for constructing mathematical models of metal plates of various structures are proposed.

A Finite Element Analysis Based Study on Effects of Polyurea Coating for Blast Mitigation

One of main threats for Armoured fighting vehicles (AFVs) is anti-tank mines. Future war scenario insists on light tanks that can withstand land mines with higher order destruction. Hence a non-classical approach for blast mitigating structures has dealt with. In this sequence, there are two kinds of approach, one is to redesign the bottom plate structure and second is using special materials for coating. This work investigates the effect of special material Viz., Polyurea coating on the bottom structure of the AFV hull. Polyurea coating added to the Steel plate (considered as localized AFV vehicle hull structure) in such a way that the coating thickness is lesser than the thickness of base material. Explicit dynamic Finite Element (FE) based numerical simulations were performed using ANSYS AUTODYN. In this setup, coating is introduced to the Steel plate in two variations, namely, on non-blast face (opposite to the blast load) and blast face. The simulation is carried out with varying coating thickness (6mm, 8mm, 10mm 14mm) and with varying blast charges of TNT (2kg, 5kg, 7kg, and 12kg) in the stand-off distance (distance from the center of the explosive to the plate) of 450mm. The peak deformation of the plate caused by the blast load on the coated and uncoated homogenous plate is compared for their relative performances.