AP Method Research Articles

Investigation of the hot corrosion effects on the lifetime of TBCs with and without TC

This paper investigates the influence of hot corrosion on the lifetime of TBCs with and without top coat under cyclic thermal loading. The tests were performed on two types of samples: Type A coating consisting solely of a bond coat (BC) fabricated by the HVOF method, and type B coating comprising a BC fabricated by the HVOF method and a TC fabricated by the APS method. The lifetime and degradation mechanism of these two types of coatings under hot corrosion in the presence of sulfate and vanadate molten salts were compared. The lifetime of type A and B coatings under the hot corrosion test is 31 and 24 cycles, respectively. Results indicate that the TGO acts as a barrier against the penetration of corrosive salts and delays the degradation of the type A coating. XRD patterns reveal that the reaction products of BC with molten salts are (Co,Ni)3(VO4)2 and (Cr,Al)VO4. In the type B coating, YVO4 is formed as a hot corrosion product due to the reaction of molten salts with yttria. With the depletion of yttria, the phase transition of zirconia from tetragonal to monoclinic causes volumetric expansion and coating degradation.

Process optimization of acq-polyacrylate modified bamboo aggregate and durability analysis of all-bamboo aggregate concrete

All-Bamboo Aggregate Concrete (BAC) is a type of cement concrete material where all coarse aggregates are made of bamboo aggregate, a plant material that requires necessary measures to avoid or slow down its degradation in alkaline and natural environments. This paper enhances the durability of BAC materials through the treatment of bamboo aggregate with ACQ-polyacrylate (AP method). Initially, the study explores the impact of polyacrylate dilution concentration on the compressive strength and coating thickness of BAC, and based on a reasonable modification process, conducts freeze-thaw cycles, salt solution immersion, accelerated wet-dry aging, and long-term natural environment tests to assess the durability of BAC materials. The results show that a polyacrylate solution with a dilution ratio of 1:5 can form a coating thickness of 23.8μm, performing better in various durability evaluations. After 25 freeze-thaw cycles, the BAC material's loss rate of compressive strength is lower than that of Ordinary Concrete (OC). Compared with OC, BAC materials are more susceptible to salt damage after salt solution immersion. The compressive strength loss rate under 180 days of natural environment exposure is comparable to that in 10 cycles of accelerated wet-dry aging, 28 days of salt solution immersion, and 10–15 freeze-thaw cycle tests, recommending the use of freeze-thaw cycle tests for evaluating the durability of BAC materials from an experimental efficiency perspective. By exploring the durability of BAC materials, this paper provides an innovative solution in the field of construction materials, promoting the transition of the construction industry towards sustainable development. It emphasizes the feasibility and effectiveness of improving the performance of bamboo-based materials through surface treatment technology, offering a valid reference for developing more environmentally friendly and high-performance new materials in the future.

Oxidation behavior of AlCoCrFeNi bond coating in the YSZ-TBCs produced by APS and PS-PVD method

This study prepared the 7YSZ ceramic coatings based on AlCoCrFeNi bond coating by APS and PS-PVD methods, respectively. Two AlCoCrFeNi/7YSZ thermal barrier coating systems with different microstructures of ceramic coatings were obtained, and oxidation experiments at 1000 °C and 1100 °C were carried out for the two thermal barrier coating systems. The results showed that the AlCoCrFeNi/7YSZ(PS-PVD) thermal barrier coating system exhibits superior oxidation resistance compared to the AlCoCrFeNi/7YSZ(APS) thermal barrier coating system at 1000 °C and 1100 °C, which was attributed to the ceramic coating with a unique feather-columnar structure prepared by PS-PVD. Both thermal barrier coatings in this study produced a continuous and dense TGO layer composed of Al2O3 after oxidation experiments. The oxidation rate constants kp of this study's two thermal barrier coatings were lower than the selected MCrAlY/YSZ thermal barrier coating systems under the same experimental conditions. It indicates that the AlCoCrFeNi bond coating exhibited excellent oxidation resistance and possesses the potential to be a new type of bond coating material.

Standard technical specifications for methacholine chloride (Methacholine) bronchial challenge test (2023)

Standard technical specifications for methacholine chloride (Methacholine) bronchial challenge test (2023)

Qualification of Compensatory Test Methods Involving Pressure Increase in the VVER Containment System

In general, containment leakage testing of nuclear power plants with VVER reactors by elevated pressures using the compensatory leakage detection method (CLDM) can be performed at pressures and pressure increase rates higher than those stipulated by the regulations using the absolute pressure method (AP method). Elevated pressures and pressure increase rates under certain conditions can violate safety limits of the containment systems and/or decrease the reliability/life of containment structures and equipment. These factors determine the need to qualify the CLDM to promote conditions for reliability and safety. A non-stationary thermodynamic model of the qualification conditions for CLDM testing of the containment was developed. The criteria for CLDM qualification conditions are the maximum allowable pressure and pressure increase rate during testing. The CLDM condition for recording leakage in the containment is pressure stabilization in the containment systems. Based on the developed CLDM thermodynamic model, it was established that the containment leakage rate is determined by the flow rate of air entering the containment systems and by the thermodynamic state of the air inside and outside the containment systems. The established qualification conditions were used to determine conditions for the minimum recorded leakage sizes within CLDM and the maximum allowable ambient air flow rates and test duration. A prerequisite for justifying the qualification and implementation of the CLDM is to revise/amend regulatory and technical requirements for the maximum allowable pressure and pressure change rate in the containment systems and for the conditions for disconnecting containment systems passive heat removal systems (if any) during testing.

Effect of Pore Evolution on Thermal Diffusivity and Radiation Characteristics of Thermal Barrier Coatings after High-Temperature Exposures

Studying the impact of pores is crucial to enhancing the service performance of coatings, since they are a typical microstructure feature of thermal barrier coatings. In this paper, a coating prepared by the APS method was employed as the study object, and a scanning electron microscope and optical microscope were used to calculate the porosity after spraying or high-temperature exposures. Based on this, numerical calculations and simulations were used to evaluate the impacts of the pore structure and porosity on the heat conductivity and radiation characteristics of the coating. The results showed that, at high-temperature exposures, the horizontal pores inhibited thermal conductivity and radiation, but the column pores increased heat conductivity and radiation. The heat conductivity of the coating linearly decreased as the porosity increased, whereas the extinction coefficient increased, although at a slower and slower pace. When the porosity reached 15%, if the porosity was further increased, the thermal radiation energy did not change much, indicating that increasing the porosity would only block the heat radiation to a certain amount. This new and time-saving technique for materials research utilizing simulation and numerical computing may be utilized to optimize the microstructure of coatings to increase their service performance.

Measurement of Intervertebral Disc Heights in the Lumbar Spine. Comparison of X-Ray and Magnetic Resonance Imaging, Method of Measurement and Determination of Inter-observer Reliability.

Retrospective radiological examination (X-ray and MRI) aims to investigate the diagnostic value of various methods of measurement with regard to the determination of the intervertebral disc heights of the lumbar spine. Of 130 patients without detectable damage to the intervertebral discs, the X-ray and MRI images of the lumbar spine were evaluated. The measurements were made either in the center line (Hurxthal) or in the 2-point method according to Dabbs or in the 3-point method according to Fyllos. The average intervertebral disc height for all measured segments was 8.8mm (SD 1.4mm). In the Hurxthal measurement, the significantly (p<0.001) highest values were measured with an average of 9.1mm (SD 1.3mm). The average readings for the Fyllos method were 7.5mm (SD 1.2mm) and according to Dabbs 6.7mm (SD 1.2mm). The measured values of Observer I were on average 1.2mm (SD 0.3mm) smaller than those of Observer II (p<0.001). The highest interobserver correlation was found in the measurements in projection radiography in the AP method according to Dabbs and Fyllos. The measured values in men were 0.5mm (SD 0.01mm) larger than in women (p<0.001), regardless of the method. The height of the intervertebral discs increases significantly until the age of 40, but beyond the age of 40, the height of the intervertebral discs either remains constant or falls off slightly, but not significantly. The lordosis angle of the lumbar spine and the concavity index of the vertebral bodies showed no correlation with the measured disc heights. The radiological measurements to determine the intervertebral disc height have only moderate reliability. The results of X-rays are superior to those of MRI examination. The most accurate results are provided by measurements based on exact landmarks of the vertebral bodies. The method according to Dabbs seems to be the most accurate at the moment. There is no clear age-atypical chondrosis in patients without intervertebral disc damage.

The effect of CMAS penetration on the microstructure and failure of the TBCs applied by APS/APS method

This study investigates the effect of CMAS (CaO-MgO-Al2O3-SiO2) penetration with different dosages on TBCs applied by the APS/APS method. For this purpose, CMAS powder at dosages of 5 and 15mg/cm2 was applied on the surface of laboratory samples. The samples, which were heated for 4 h, were made by Inconel 738 with BC and TC layers. CMAS sediments were melted at 1200 °C and penetrated the pores and cracks in the microstructure of TBCs. It was observed that at a low dosage of CMAS elements, horizontal cracks appear in the middle parts of the TC layer. However, crack formation was close to the TC and BC interface at a high CMAS dosage. The reaction of CMAS with the Y in the ceramic layer leads to its discharge. XRD analysis has shown a phase change in the ceramic layer from YSZ-t to YSZ-m caused by the CMAS attack. This phase change is accompanied by an increase in volume, causing buckling of the TC. Further, the presence of CMAS in the ceramic layer made a CTE gradient in this layer, which also intensifies the buckling. In this study, OOF2 software was used to determine the ceramic layer's thermal conductivity changes using SEM images. To validate the numerical results calculated by OOF2 software, the LFA method has been used to determine the thermal conductivity changes in the ceramic layer. It was observed that the presence of CMAS elements increased the thermal conductivity of the TC layer by 49.5 %, leading to an increase in the growth rate of the TGO layer by 1.5 times. This phenomenon caused the degradation of the TC layer to occur more severely.

A three-dimensional dynamic mode decomposition analysis of wind farm flow aerodynamics

High-fidelity large-eddy simulations are suitable to obtain insight into the complex flow dynamics in extended wind farms. In order to better understand these flow dynamics, we use dynamic mode decomposition (DMD) to analyze and reconstruct the flow field in large-scale numerically simulated wind farms by large-eddy simulations (LES). Different wind farm layouts are considered, and we find that a combination of horizontal and vertical staggering leads to improved wind farm performance compared to traditional horizontal staggering. We analyze the wind farm flows using the amplitude selection (AP) and sparsity-promoting (SP method) DMD approach. We find that the AP method tends to select modes with a small length scale and a high frequency, while the SP method selects large coherent structures with low frequency. The latter are somewhat reminiscent of modes obtained using proper orthogonal decomposition (POD). We find that a relatively limited number of SP-DMD modes is sufficient to accurately reconstruct the flow field in the entire wind farm, whereas the AP-DMD method requires more modes to achieve an accurate reconstruction. Thus, the SP-DMD method has a smaller performance loss compared to the AP-DMD method in terms of the reconstruction of the flow field.

Study of medium frequency transformer by using ultra‐thin silicon steel sheet in DC‐DC converter

In order to solve the problems of poor thermal stability and high frequency noise of transformer in traditional DC-DC converter, the medium frequency transformer in isolated DC-DC converter is designed and studied, which adopts 0.15 mm ultra-thin silicon steel sheet. Firstly, the magnetism of ultra-thin silicon steel is measured by using single-piece silicon steel sheet measuring device, and the B-H curves and B-P curves at different frequencies are given. According to the magnetic measurement results, the electromagnetic scheme of three port medium frequency transformer is designed by AP method and applied the particle swarm algorithm to further design under the constraint of loss minimization. Secondly the three-winding transformer of DC-DC converter is optimized and simulated. The magnetic flux density, loss, temperature field distribution, output voltage and current waveform of the transformer under different working conditions are given. Finally, the 20 kW DC-DC converter was manufactured and the magnetic characteristics of the medium frequency transformer were experimented to verify the correctness of the proposed scheme.

Assessment on the Progressive Collapse Resistance of a Long-Span Curved Spatial Grid Structure with Main Trusses

The progressive collapse resistance of the terminal building of Zhongchuan Airport in Lanzhou, China was studied, which is a long-span curved spatial grid structure with main trusses. Firstly, the finite element model was built using MSC. Marc software adopting the fiber model based on material. Secondly, an improved method of zoned concept judgment and sensitivity analysis was proposed to determine the key components. Thirdly, the initial failure components were removed individually based on the alternate load path method (AP method). The responses of remaining structure were calculated using nonlinear dynamic analysis method. Lastly, the influences brought by the cross-sectional sizes of grid members were investigated through conducting parametric analysis. According to the results, the proposed selection method can avoid omitting the key components. The structural responses are significant when removing the concrete filled steel tubular (CFST) column SC14 directly supporting the front middle part of the roof, with a maximum vertical displacement of 10 m at cantilever end, which should be focused on for this kind of large-span spatial structure. In addition, the tensile strength and cross-sectional area of the upper and lower chords should be increased by 20% to enhance the progressive collapse resistance of the structure, and the changes of axial compression ratios of the columns supporting the roof have little effects.

Effect of processing methods on the cytotoxicity of methyl methacrylate-based ocular prostheses: An in vitro study

The study evaluated the influence of cycles and methods of an ocular prosthesis resin on cytotoxicity toward human conjunctival cells. Resins were polymerized by water bath (WB, 74 °C or 100 °C for 30 min to 9 h), microwave (MW, 1200 W, 3 to 14 min and 30 s at 0 to 720 W), or autopolymerization (AP, room temperature for 20 min ± 60 °C for 30 min). Degree of conversion (DC), cytotoxicity, level of inflammatory mediators, gene expression of different markers, and apoptosis were evaluated. Data were submitted to ANOVA and Tukey test (p < 0.05). WB with longer processing time at higher temperature had highest DC (85.6%) and higher TGF β1-gene expression (1.39); long cycle low power MW showed lowest DC (69.6%), lower cell proliferation (85.4%, MTT), and large IL-2 release (39,297 ng/mL). AP with additional processing time showed lower cell proliferation (75.3%, Alamar Blue), and AP polymerized at room temperature showed higher CASP 9-gene expression (1.21). AP methods showed higher IL-6 release (>277 pg/mL). Short cycle medium power MW had higher IL-23 release (534.2 pg/mL). MW (long and short cycles) and AP polymerizations have triggered a more intense inflammatory response. Among methods recommended by the manufacturer, WB showed high DC and less cytotoxicity.

Research on the verification method of flyback high-frequency transformer (FHFT) based on field-circuit coupling model

In view of the current status of research on verification of the correctness and effectiveness of FHFT design, a field-circuit coupling based FHFT design verification method is proposed in this paper. This paper proposes a FHFT design verification method based on field-circuit coupling. The steps of FHFT verification using field-circuit coupling method are elaborated in detail. A three-dimensional physical model of FHFT based on AP method is established. The calculation of FHFT flux density and the verifying of transformer output waveform are completed by using the field-circuit coupling method of alternating iteration of non-linear magnetic field solution and circuit. On the basis of completing the flux density calculation, the field circuit coupling method is used to verify the output waveform of the transformer. It is found that the output waveform of FHFT is not an ideal square wave, but has some distortion, which is caused by neglecting the leakage inductance of transformer in the design process. This shows that the influence of transformer leakage inductance is very important and should be paid attention to.

Performance Analysis Similarity Matrix, Responsibility Matrix, Availability Matrix, Criterion Matrix of Affinity Propagation

Each process in classifying data into several clusters or grouping so that the data in one cluster has a maximum similarity level and between clusters has a minimum similarity is called clustering. Clustering is divided into 2 approaches in its development, namely the partitioning and hierarchical approach to clustering[1]. The Water Quality Status dataset has 8 attributes, 4 classes and 120 instances, Class distribution is good condition (30 instances), lightly polluted (30 instances), medium polluted (30 instances) and heavily polluted (30 instances). 70% of the data will be used as training data and 30% of the data will be used as randomized test data. The simplify the process of completing the performance calculation of the clustering model, the research implementation was carried out using the MATLAB function. That iteration is carried out with the number of clusters generated from 100 to 2,500 iterations with the results of the number of clusters as many as 10 clusters. In the experiment, iteration amounted to 5000 and there was a change in the results of the number of clusters by 9 clusters. After re-testing using the number of iterations of 10,000-50,000 iterations, but the number of clusters produced did not change anything at all. So that the conclusion in testing the AP method produces the most optimal number of clusters of 10 clusters.

Сравнительная оценка мобильного лазерного сканирования, аэрофотосъемки с беспилотной авиационной системы и съемки с комплексной дорожной лаборатории при выполнении диагностики автомобильных дорог

Objective: To compare the possibilities of using mobile laser scanning (MLS) and aerial photography (AFS) from an unmanned aircraft system (UAS) and to make a survey from an integrated road laboratory when performing diagnostics of highways. Methods: For the analysis, a section of the regional road in the Kursk region was selected, on which the survey was carried out using considered methods. The main characteristics were identified when performing the diagnostics, their values were obtained on the basis of data from the integrated road laboratory, aerial photography with UAS, as well as ILS, and the accuracy of the results obtained, the compliance of the data with the requirements of regulatory documents were assessed. Results: Based on the work performed, the following conclusions were made: the determination of identified diagnostic parameters by the methods of ILS and APS with UAS is correct and aerial photography with UAS at the cost of equipment, the cost of shooting is the most profitable when drawing up topographic road plans. It is noted that in terms of accuracy, the APS method meets the requirements for plans at a scale of 1:500, MLS – 1:1000. Practical importance: Not all indicators required for diagnostics can be obtained with APS with ALS and MLS, since they require specialized equipment and direct interaction with the road surface, however, the range of application of the selected methods can be significantly expanded. Adhesion coefficient is measured using an integrated mobile road laboratory, so it is not advisable to abandon it. It was noted that the equipment of the laboratory, depending on the cost, may be different

MODIFIED V-Y VOLAR FLAP(ATASOY) TO COVER THE FINGER TIP AMPUTATION

Purpose: Inadequate mobility of Atasoy and Kutler V-Y ap Method: Prospective clinical study Result: Adequate mobility was achieved to cover the stumps of terminal amputation of ngers Conclusion: Modied V-Y volar ap which is reliable and can be easily executed by junior reconstructive surgeons with good postoperative outcome in terms of sensation, length and appearance Summary: Inadequate mobility of Atasoy's V-Y advancement ap to cover the nger tip raw area prompted us to modify the Atasoy's technique. Both the digital neurovascular bundles are identied and included in this modication, thereby, increasing the mobility and reliability with good recovery of function, sensation and appearance. None of aps was lost out of twenty two nger amputations treated by this modied technique. This technique can be easily executed by junior trainee doctors as we incorporate the relatively larger vessels(unlike the digital perforators)which are easily identied by simple loupe magnication.

Spatial interpolation of the extreme hourly precipitation at different return levels in the Haihe River basin

The return level is an important measure for the extreme precipitation, and maps of the return level are used to derive information for the design of hydrological and hydraulic engineering projects. The interpolation of hourly extreme precipitation is challenging due to low station density and high inhomogeneity. Hourly precipitation observations at 232 weather stations in the Haihe River basin from 1961 to 2012 were used to evaluate six interpolation methods including Inverse Distance Weighted (IDW), Ordinary Kriging (OK), Kriging with External Drift (KED) assisted by different covariables and Empirical Bayesian Kriging (EBK) for generating 2-, 5-, 10-, 20-, 50-, and 100-year return level maps for the basin. Leave-one-out cross-validation showed that although there was a high correlation coefficient between hourly extreme precipitation and the elevation (DEM), KED incorporating DEM as the covariable (KED_DEM) did not improve the interpolation efficiency compared with OK. KED with the annual average precipitation as the covariable (KED_AP), which had the largest Nash-Sutcliffe efficiency coefficient (NSE, 0.89–0.45) and the smallest root mean square error (RMSE, 2.23–15.05 mm) for the six return levels, outperformed the other five methods compared. The return levels varied from 13 to 46, 20–66, 24–78, 26–89, 29–110 and 30–134 mm, with mean values of 30, 40, 48, 57, 67 and 75 mm for the 2-, 5-, 10-, 20-, 50- and 100-year return levels, respectively, in the Haihe River basin. The return level maps of extreme hourly precipitation in the Haihe River basin were generated based on the KED_AP method and showed a spatial distribution of decreasing trend from the southeastern part to the northwestern part of the basin. The high-value centre moved from the eastern coastal area for smaller return level maps to the southern area for the 50- and 100-year return level maps. This study may provide some insights into the spatial interpolation of extreme precipitation on an hourly scale.

Research on the Verification Method of Flyback High-Frequency Transformer (FHFT) Based on Field-Circuit Coupling Model

In view of the current status of research on verification of the correctness and effectiveness of FHFT design, a field-circuit coupling based FHFT design verification method is proposed in this paper. This paper proposes a FHFT design verification method based on field-circuit coupling. The steps of FHFT verification using field-circuit coupling method are elaborated in detail. A three-dimensional physical model of FHFT based on AP method is established. The calculation of FHFT flux density and the verifying of transformer output waveform are completed by using the fieldcircuit coupling method of alternating iteration of non-linear magnetic field solution and circuit. On the basis of completing the flux density calculation, the field circuit coupling method is used to verify the output waveform of the transformer. It is found that the output waveform of FHFT is not an ideal square wave, but has some distortion, which is caused by neglecting the leakage inductance of transformer in the design process. This shows that the influence of transformer leakage inductance is very important and should be paid attention to.

Hot corrosion behavior of plasma sprayed La2Ce2O7/YSZ thermal barrier composite coating in the presence of Sulfate and Vanadate molten Salts

In this study, LC and YSZ coatings and composite coatings consisted of LC and YSZ with 25LC-75YSZ, 50LC-50YSZ and 75LC-25YSZ compounds are created via APS method and their hot corrosion behavior is investigated. Several analyses, including XRD, EDS and FESEM were employed to study characteristics of coatings. The results showed that the highest and lowest hot corrosion resistance are related to the LC and YSZ coatings, respectively, because of maximum percentage of tetragonal to monoclinic transformation as well as formation of cavity and crack. Besides, composite coating 75LC-25YSZ showed the best corrosion behavior compared to YSZ and the other ones.

Ablation behaviour of ZrC coating by novel solid shielding/shrouded plasma spray

ABSTRACTIn this study, for the first time, ZrC coating was deposited on SiC coated graphite by optimized atmospheric plasma spray (i.e. solid shielding shrouded plasma spray (SSPS)) method. Then SSPS-ZrC coatings were compared with the atmospheric plasma spray APS-ZrC coatings. The results indicated that the the SSPS-ZrC coated sample had lower porosity compared with APS-ZrC coating (3% and 7.5% respectively) and the ablation test revealed that the linear and mass ablation rates of the ZrC coating applied by APS method were 3.7×10−3 mm.s−1 and 22×10−3 g.s−1, while those for SSPS coating were 2.2×10−3 mm.s−1 and 14×10−3 g.s−1, respectively. The results showed that applying the ZrC coating with the SSPS method can improve the ablation resistance of the equipment used in harsh conditions, significantly. It is attributed to the formation of a continuous zirconia (ZrO2) layer on the surface during the ablation test of the ZrC coating.