Influence Of Laser Cladding on Behavior of Fatigue and Fatigue Corrosion

Nickle based super alloys such as Inconel 600 are being extensively used to manufacture turbine blades for jet engines since their superior mechanical characteristics at higher working temps. The chemical composition of steam turbine blades show that is steel 52 it has a wide range of Energy, Tanks, Rail, Yellow Goods, Engineering, Bridges, Construction, applications. Laser cladding seems to be a surfacing method that uses lasers to improve the characteristics of a component’s surface and/or renew it. Laser cladding involves absorption of laser light that melts a small area of the substrates against which the substance was being introduced and fuses the coating substance to the substrates, resulting in the formation of a new layer. This research aims to investigate the fatigue and fatigue corrosion behavior of these turbine blades before and after exposure to laser cladding. The cladding process applied with this parameter Pulse energy = 11 joules, Pulse width = 6 Ms., Pulse frequency = 12 Hz, Laser Average Power = 132 W, Laser peak power = 1.83 KW. The results show, after cladding process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without laser cladding process. So, the fatigue resistance is increased.

Effect of Laser Process on Microstructure and Fatigue Resistance of Steam Turbine Blade

The steal turbine blades, operating in steam electricity production plants are subjected to periodic circular stresses that cause fatigue failure with the passage of time. The chemical composition so steam turbine blades show that is steel 52 it has a wide range of applications, mostly in welded construction, All kinds of welded construction, wind turbines, load-lifting equipment, platform components, cranes, bridge components, and structures. This research aims to study the microstructure of these turbine blades before and after the occurrence of fatigue, and for the purpose of improvement the fatigue resistance, the blades were treated with a laser and the amount of improvement in fatigue resistance was calculated and also the change in the microstructure after laser treatment was studied. The remelting process applied with this parameter Pulse energy = 8 joules, Pulse width = 4.5 Ms., Pulse frequency = 12 Hz, Laser Average Power = 96 W, Laser peak power = 1.78 KW. The results show, after remelting process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without leaser remelting process. So, the fatigue resistance is increased.

Effect of Pulsed Jet on Pore Pressure of Deep Formation Rock

Pulsed jet significantly affects the pore pressure of deep formation and then affects the mechanical ROP. In this paper, the effect of jet pulsation on deep pore pressure in the formation is studied by the finite element method. Under the pulsed jet, the maximum relative negative pressure is along the wellbore axis, and the farther it is to the borehole axis, the smaller the relative negative pressure is. With the increase of pulse frequency, the relative negative pressure increases and the maximum point of relative negative pressure moves upward. The optimum pulse frequency is from 50 Hz to 500 Hz. There is a linear relationship between pulse amplitude and relative negative pressure.

Effect of pulse injection on film cooling performance: Experimental and numerical investigation

In this paper, the influence of pulsating air on film cooling of a flat plate at different frequencies and blowing ratios are experimentally and numerically investigated. Square wave pulsed flow is generated at four frequencies of 2, 10, 50, and 100 Hz corresponding to Strouhal numbers of 0.00254, 0.0127, 0.0636, and 0.1271, respectively, and at five blowing ratios of 0.5, 1, 1.5, 2.4, and 3. Reynolds-averaged Navier−Stokes equations are resolved to analyze the coolant film effectiveness based on parameters set in the experiments. The [Formula: see text] model used for turbulent modeling. The obtained results showed that the performance of pulsating cooling decreases with increasing of blowing ratio at the same flow as steady state conditions. The difference between numerical and experimental values for the centerline film effectiveness shows good adaptation at the distances of the injection hole downstream. The lift-off of the local jet increased under pulsation. Increasing the pulse frequency increases the overall efficiency of film cooling. The maximum mean centerline pulsating film cooling effectiveness is obtained at Strouhal number of 0.0636 and a blowing ratio of 0.5, and the minimum value is for Strouhal number of 0.00254 and a blowing ratio of 3. For pulsed flow, the maximum discrepancy of the mean centerline film effectiveness between experimental and numerical results was 17.82%.

COMPARISON ASSESSMENT OF DIGITAL 3D MODELS OBTAINED BY DRONE-BASED LIDAR AND DRONE IMAGERY

The purpose of this study is to assess the potential of drone airborne LiDAR technology in Morocco in comparison with drone photogrammetry. The cost and complexity of the equipment which includes a laser scanner, an inertial measurement unit, a positioning system and a platform are among the causes limiting its use. Furthermore, this study was motivated by the following reasons: (1) Limited number of studies in Morocco on drone-based LiDAR technology applications, (2) Lack of study on the parameters that influence the quality of drone-based LiDAR surveys as well as on the evaluation of the accuracy of derived products. In this study, the evaluation of LiDAR technology was carried out by an analysis of the geometric accuracy of the 3D products generated: Digital Terrain Model (DTM), Digital Surface Model (DSM) and Digital Canopy Model (DCM). We conduct a comparison with the products generated by drone photogrammetry and GNSS surveys. Several tests were carried out to analyse the parameters that influence the mission results namely height, overlap, drone speed and laser pulse frequency. After data collection, the processing phase was carried out. It includes: the cleaning, the consolidation then the classification of point clouds and the generation of the various digital models. This project also made it possible to propose and validate a workflow for the processing, the classification of point clouds and the generation of 3D digital products derived from the processing of LiDAR data acquired by drone.

MATHEMATICAL MODELS OF COATING PROPERTIES UNDER DIFFERENT TECHNOLOGICAL MODES OF PEO

The issue of mathematical modeling of the coating thickness, current and corrosion potential depending on the type of pulsed electrical processing mode, pulse frequency and processing duration is considered.

PRONATION POSITION OF OXYGEN SATURATION, RESPIRATORY AND PULSE FREQUENCY IN LOW BIRTH WEIGHT BABIES

Introduction: Data from WHO 2018 shows the prevalence of LBW is estimated at 21% globally with a limit of 4.5%-40%. LBW babies often have complications in the form of Respiratory Distress Syndrome and an increase in pulse rate. One way to prevent complications is to place the baby in a prone position. Based on scientific article searches, this literature review aims to determine the effect of pronation position on oxygen saturation, pulse rate, and respiratory rate in LBW infants. Method: The type of research was a Literature Review with meta-analysis. Journal searches are carried out on the electronic basis of Google Scholar, Garuda Portal, One Search, and Pubmed, totaling 30 articles. The literature used is literature published from 2016 - 2021. Results: The study results of 30 articles found that the average oxygen saturation before and after being given a pronation position was in the range of 90.27% - 98.1%. The average pulse frequency before and after being given a pronation position was in the range of 144.87 x/minute -140.90 x/minute. The average breathing frequency before and after being given a pronation position was in the range of 69.50 x/minute – 44.18 x/minute. All articles have the effect of pronation position on oxygen saturation in infants (LBW). There is an effect of pronation position on oxygen saturation, respiratory, and pulse with p-value <0,05. Conclusion: It was concluded that the pronation position affected the oxygen saturation, pulse rate, and respiratory frequency in LBW infants. It is expected for nursing services to make the provision of a pronation position as one of the nursing interventions and become a standard operating procedure in the management of LBW infants.

Wear Behaviors of Carbon–Chromium Carbide–Chromium Multilayer Coatings Prepared by Reactive High-Power Impulse Magnetron Sputtering

Carbon–chromium carbide–chromium multilayer coatings were deposited by utilizing reactive high-power impulse magnetron sputtering with alternating various ratios of ethyne and argon mixtures under a constant total deposition pressure, target pulse frequency, pulse duty cycle, average chromium target power, and total deposition time. Two different alternating gas mixture periods were applied to obtain films with different numbers of layers and lamination thicknesses. The results show that the reduction in the modulation period effectively affects the elastic modulus and the subsequent ratio of hardness to elastic modulus (H/E) of the whole coating, which helps adapt the elastic strain in the coating. This improves the adhesion strength and wear resistance of coatings at room temperature. However, with the increase in wear test temperature, the difference between the wear behaviors of two types of coatings becomes inconspicuous. Both types of coatings lose the wear resistance due to the decomposition of hydrocarbon and the oxidation of the chromium content in the films.

Исследование градуировочной характеристики турбинных преобразователей расхода жидкости типа MVTM

Most of the failures of turbine flow converters (TFC) used in the Russian system of main oil pipelines and oil product pipelines are caused by abrupt changes in the viscosity of the transported medium. In studies related to determination of the influence of the rheological properties of the pumped oil on the metrological characteristics of TFC that have a calibration curve in the form of a piecewise approximation without taking into account the correlation of TFC rotor speed with the viscosity of the pumped liquid in the flow rate subrange, the instability of the metrological characteristics in the operating range is observed. Taking into account the tendency to increase the volume of production and pumping of high-viscosity oils it can be assumed that the irregularity of the metrological characteristics of TFC, expressed in the change in the conversion factor will remain, which will negatively affect the reliability of accounting operations using oil quality control system (OQCS). Accordingly there is a need to maintain the error of TFC within the set limits in the subranges and throughout the entire range of flow rates. According to the results of the study performed by the authors it was confirmed that for the TFC of MVTM type the use of the calibration curve in the form of a piecewise-parabolic approximation with the dependence of the conversion factor on the ratio of TFC pulse frequency to the oil viscosity makes it possible to minimize the effect of changes in the parameters of the pumped medium on the measurement accuracy and as a consequence to stabilize the metrological characteristics of TFC in the recalibration interval, eliminate the costs of performing out-of-turn verifications, increase the accuracy and metrological reliability of the OQCS. Большинство отказов турбинных преобразователей расхода (ТПР), используемых в российской системе магистральных нефтепроводов и нефтепродуктопроводов, обусловлено резкими изменениями вязкости транспортируемой среды. В исследованиях по определению влияния реологических свойств перекачиваемой нефти на метрологические характеристики ТПР, имеющих градуировочную характеристику в виде кусочно-линейной аппроксимации без учета корреляции частоты вращения ротора ТПР с вязкостью перекачиваемой жидкости в поддиапазоне расхода, отмечается нестабильность метрологических характеристик в рабочем диапазоне. Учитывая тенденцию увеличения объема добычи и перекачки высоковязких нефтей, можно предположить, что непостоянность метрологических характеристик ТПР, выражаемая в изменении коэффициента преобразования, сохранится, что негативно скажется на достоверности учетных операций с применением систем измерений количества и показателей качества нефти (СИКН). Соответственно, возникает потребность в поддержании погрешности ТПР в установленных пределах в поддиапазонах и во всем диапазоне расходов. По результатам проведенного авторами исследования подтверждено, что для ТПР типа MVTM использование градуировочной характеристики в виде кусочно-параболической аппроксимации с зависимостью коэффициента преобразования от отношения частоты импульсов ТПР к вязкости нефти позволяет минимизировать влияние изменений параметров перекачиваемой среды на точность измерений и, как следствие, стабилизировать метрологические характеристики ТПР в межповерочном интервале, исключить затраты на выполнение внеочередных поверок, повысить точность и метрологическую надежность СИКН.

Deletion of Gαq/11 or Gαs proteins in gonadotropes differentially affects gonadotropin production and secretion in mice

GnRH regulates gonadal function via its stimulatory effects on gonadotropin production by pituitary gonadotrope cells. GnRH is released from the hypothalamus in pulses and GnRH pulse frequency differentially regulates FSH and LH synthesis and secretion. The GnRH receptor (GnRHR) is a G protein-coupled receptor that canonically activates Gαq/11-dependent signaling upon ligand binding. However, the receptor can also couple to Gαs and in vitro data suggest that toggling between different G proteins may contribute to GnRH pulse frequency decoding. For example, as we show here, knockdown of Gαs impairs GnRH-stimulated FSH synthesis at low, but not high pulse frequency in a model gonadotrope-derived cell line. We next used a Cre-lox conditional knockout approach to interrogate the relative roles of Gαq/11 and Gαs proteins in gonadotrope function in mice. Gonadotrope-specific Gαq/11 knockouts exhibit hypogonadotropic hypogonadism and infertility, akin to the phenotypes seen in GnRH- or GnRHR-deficient mice. In contrast, under standard conditions, gonadotrope-specific Gαs knockouts produce gonadotropins at normal levels and are fertile. However, the LH surge amplitude is blunted in Gαs knockout females and post-gonadectomy increases in FSH and LH are reduced in both males and females. These data suggest that GnRH may signal principally via Gαq/11 to stimulate gonadotropin production, but that Gαs plays important roles in gonadotrope function in vivo when GnRH secretion is enhanced.