Ascent Stage Research Articles

A Continuous Flow Boiling Curve in the Heating Configuration Based on New Cryogenic Universal Correlations

To enable the design of future in-space cryogenic propellant vehicles such as Lunar and Martian ascent and descent stages, fuel depots, and nuclear thermal propulsion systems, high-accuracy models of various phases of the propellant transfer process are required. This paper focuses on modeling steady-state flow boiling through the transfer line that connects a propellant tank to an engine or customer receiver tank, which is required to set limits on the allowable heat flux into the line. Using the largest-ever collection of available cryogenic heated tube data, universal cryogenic flow boiling correlations were recently developed for various regimes of the boiling curve and their transition points. However, to model flow boiling in heated tubes, these individual correlations must be patched together to provide a continuous predictive curve of wall superheat as a function of preponderant parameters. This paper provides an overview of the individual flow boiling correlations along with the logic and rationale for patching the correlations together to produce a single continuous boiling curve. Resulting flow boiling curves are presented for different possible permutations of independent inlet and flow conditions for illustration.

Spatio-temporal distribution of aerodynamic forces and their associated vortex drift patterns around a closed-box girder during torsional vortex-induced vibration

Torsional vortex-induced vibrations (VIVs) pose potential risks to prototype bridges with increasing spans and lower damping levels. However, the underlying mechanism remains unclear. Wind tunnel tests revealed that torsional VIVs occurred at an initial attack angle of + 3°. To unravel the VIV mechanism throughout the lock-in range, encompassing the ascent stage, amplitude extremum, and descent stage, the spatio-temporal distribution of aerodynamic forces around the bridge girder was analyzed. The results demonstrated the presence of traveling pressure waves with approximately 2.5 wavelengths and three uniformly distributed separated vortices over the upper side throughout the lock-in range. The primary source of these travelling pressure waves stemmed from the vortex drift patterns, with the aerodynamic wave travelling velocity equating the vortex drift velocity. The formation of separated vortices, known as the “double-vortex model”, occurred at the windward barrier on the upper side and windward maintenance rail on the lower side. These vortices directly imposed travelling pressure waves on the girder, thereby inducing torsional VIVs. Among them, the former vortices contributed more to the VIVs than the latter. Therefore, the formation of separated vortices and their related aerodynamic waves in the windward edge with the 2nd SVM/AWM modes predominantly governed the occurrence of torsional VIVs. Furthermore, both the ratio of the wave travelling time to the vibration period and the mean value of the wave travelling velocity ratio exhibited an inverse relationship with the VIV responses. However, the actions exerted by the vortex drift patterns were proportional to the VIV responses on both the upper and lower sides. Therefore, there existed evolutionary characteristics of aerodynamic waves and their related vortex drift patterns throughout the lock-in range, which was responsible for the “lock-in” phenomena.

Numerical investigation of gas-liquid flow hydrodynamics in three-dimensional bottom-blown reactor via LES-VOF coupled model

In this study, a coupled interface-resolved volume of fluid model and large eddy simulation is employed to explore bubble dynamics in a three-dimensional bottom-blown reactor. After the model validation, the bubble plume area, motion characteristics, and force analysis are analyzed. Three distinct stages of bubble rising are quantitatively identified: disengaging nozzle stage, accelerated ascent stage, and stable upward stage. Specifically, an increase in reactor height reduces both the bubble rising velocity and interphase surface tension impact. Moreover, the influence of inlet size on bubble volume frequency distribution surpasses that of gas injection velocity. The gas penetration depth remains relatively unchanged amidst variations in boundary conditions, while the liquid type profoundly influences it. Axial fluid velocity, dynamic pressure, Reynolds number, and turbulent viscosity peak at the reactor center. Liquid back-mixing is found near the bottom blowing wall region, coupled with an enhanced distribution of turbulent viscosity.

Diagnostics of Flare Loop Parameters in Shrinkage and Ascent Stages Using Radio, X-ray, and UV Emission

We propose the diagnostics of plasma parameters in flare loops using the data of multi-wavelength observations in both shrinkage and expansion phases of the loops. The approach of a flare loop as an equivalent electric circuit is applied. We show that depending on plasma loop parameters, the shrinkage may be accompanied by an increase in the electric current in the loop rather than a decrease. The number density, temperature, electric current, radius, loop-top altitude, and loop volume are determined for the flare events on 16 April 2002 and 24 August 2002.

Reachable set analysis of practical trans-lunar orbit via a retrograde semi-analytic model

Different from the Apollo flight mode, a safer trans-lunar flight mode for the crews is preferred. The previous-arrived lunar module rendezvouses with the crew exploration vehicle at a low lunar destination orbit, and then the crews ride the lunar module to descend the lunar surface sampling destination. The lunar module, which includes the descent and ascent stages, flies from a low Earth orbit to the low lunar destination orbit with two tangential impulses. The low lunar destination orbital reachable set of the practical trans-lunar orbit limits the feasible lunar surface sampling region. Therefore, this paper addresses the low lunar destination orbital reachable set of the practical trans-lunar orbit. A retrograde semi-analytic model is proposed for rapidly computing the practical two-impulse trans-lunar orbit firstly, which refers the ephemeris table twice for more precision perilune orbital elements. The reachable set is generated using the multiple-level traversal searching approach with this retrograde semi-analytic mode. Its envelope is re-checked by the continuation theory with the high-precision orbital model. Besides, some factors that affect the reachable set are also measured. The results show that neither the Earth–Moon distance nor the trans-lunar duration affects the reachable set. However, if the trans-lunar injection inclination is smaller than the inclination of the moon’s path, the reachable set becomes smaller or even reduces into an empty set. In brief, the proposed retrograde semi-analytic model for computing the reachable set provides a helpful and fast tool for selecting an applicable lunar surface sampling site for the manned lunar mission overall design.Graphical

Mg3Al2Si3O12 jeffbenite inclusion in super-deep diamonds is thermodynamically stable at very shallow Earth’s depths

Jeffbenite (having the same chemical composition of pyrope, ~ Mg3Al2Si3O12, and also known as TAPP phase) is a mineral inclusion only found in diamonds formed between about 300 and 1000 km depth) and is considered a stable phase in the transition zone (410–660 km depth) and/or in the shallowest regions of the lower mantle (around 660–700 km depth). This rare and enigmatic mineral is considered to be a pressure marker for super-deep diamonds and therefore it has a key role in super-deep diamond research. However, the pressure–temperature stability fields for Mg3Al2Si3O12 jeffbenite is unknown and its actual formation conditions remain unexplored. Here we have determined the thermodynamic pressure–temperature stability field for the jeffbenite Mg-end member and surprisingly discovered that it is stable at low pressure–temperature conditions, i.e., 2–4 GPa at 800 and 500 °C. Thus, Mg3Al2Si3O12 jeffbenite is not the high-pressure polymorph of pyrope and is likely a retrogressed phase formed during the late ascent stages of super-deep diamonds to the surface.

Analysis of the influence of aerodynamic heating in ascent stage on infrared radiation characteristics of high-speed aircraft in midcourse

Analysis of the influence of aerodynamic heating in ascent stage on infrared radiation characteristics of high-speed aircraft in midcourse

Impacts of rising, peak and receding phases of discharge events on erosion potential of a boreal meandering river

AbstractFlow features of a meandering river can vary seasonally and widely in the boreal zone, as seasonal variation in discharges affect the properties of meander bends and the spatial location of flow magnitudes. However, a better understanding of the impacts of consecutive high‐discharge events in the boreal zone requires further analyses. Thus, the impacts of the fluvial processes and their magnitudes on different types of meander bends (e.g., sinuosity, symmetricity) were analysed throughout an open‐channel flow period, using accurate flow measurements and hydrodynamic (two‐dimensional) modelling. In particular, the research compared the impacts of different discharge events in magnitude and length of river evolution, and whether there is a difference in the erosion forces of the rising and falling phases of discharge hydrographs, and which of the phases has the greatest relevance to erosion forces. A case study was carried out in a middle boreal zone meandering river (Koitajoki in eastern Finland) during the 2020 open water season from May to October. Five different types of meander bends were considered in the study area. Flow magnitudes and shear forces were at their strongest during the spring flood peak, which is normally considered as the highest flow event during the hydrological year. Exceptionally, the largest summer discharge event reached a level that was close to the spring floods' maximum erosional capabilities. Bed shear stress values indicated the falling phases of the flood hydrographs are more important to river evolution than during the ascent stage, as the long duration of the flood downstage contributes more strongly to meander bend erosion and development. The smaller the curvature and larger the sinuosity of the bends, the more variation in erosional forces occurs between discharge stages. The study provides new insights into seasonal fluvial processes in boreal river meander bends as well as reinforces results from earlier river studies.

Simulation and prediction of the effect of aeration, recirculation and degradation on landfill temperature in aerobic operation.

Much heat is released in aerobic landfills, which leads to temperature change. Quantitative prediction of temperature change with time and space is essential for the safe aerobic operation of landfill. In this article, based on the theory of porous media seepage mechanics and heat transfer, a seepage-temperature coupling model considering aeration, recirculation and degradation was established, which included internal energy change, heat conduction, convection and heat transfer. Moreover, combined with the long-time on-site monitoring temperature data from Wuhan Jinkou Landfill, the model's reliability was preliminarily verified. Sensitivity analysis was carried out for aeration intensity, aeration temperature, recirculation intensity and recirculation temperature. Among the four factors, recirculation intensity influences the peak temperature most with a decrease of 20.11%. Compared with Borglin's and Hao's models, it is found that waste should not be assumed as a cell for temperature prediction. By comparing the results of Non-linear Ascent Stage model, Linear Ascent Stage model and Absent Ascent Stage model, it showed that the temperature difference of the three models decreases with the increase of operation time. In addition, the time point of peak temperature, t0, affects the temperature distribution. The above results provide a reference for predicting the spatial and temporal distribution of temperature and regulations for long-term aerobic landfill operations.

A Biomechanical Study on Failed Snatch Based on the Human and Bar Combination Barycenter.

Objective The purpose of this research was to use a new method the human and bar combination barycenter to exposit the differences between successful and failed characteristics of snatch attempts in competition. Try to establish an effective biomechanical method that can uncover the main factors for the failed snatch. The obtained results will provide valuable information for weightlifters to improve the success rate in snatch by altering their technical issues accordingly. Methods A 3-D video analysis method was used to compare the characteristics of the heaviest successful and failed attempts of ten elite weightlifters in the men's 73 kg category. The video was captured under competitive conditions at the 2019 World Weightlifting Championships, the 2019 Asian Weightlifting Championships, and the 2020 China Olympic Trial. The video data were digitized using the SIMI°Motion7.50 3-D system (Germany). Results Significant difference (P > 0.05) was not found between the successful and failed attempts in the parameters, such as the maximal vertical rising velocity, the maximal vertical height, and the vertical displacement of the barbell. The maximal descending acceleration of the human body, the time duration, the angles of the hip, and knee joints were no significant difference. However, significant differences were found in the variation of the human and bar combination barycenter on the X-axis in the inertial ascent stage and the squat support stage (t = 2.862, P < 0.05; t = 3.376, P < 0.05). Conclusions A probable cause of the failed snatch is that the displacement of human and bar combination barycenter on the X-axis is not enough to reach the position for supporting barbell during the inertial ascent stage and the squat support stage. The reason is that the strength of reclining of torso at the end of the force phase is insufficient. Insufficient knee flexion in the knee flexion phase (M2), which leads to a lower maximum vertical velocity of barbell, may be an indirect factor leading to the failed snatch. The cumulative variation of human and bar combination barycenter on the X-axis can effectively determine the technical characteristics between the success and failure in snatch.

EuLerian Identification of ascending AirStreams (ELIAS 2.0) in numerical weather prediction and climate models – Part 1: Development of deep learning model

Abstract. Physical processes on the synoptic scale are important modulators of the large-scale extratropical circulation. In particular, rapidly ascending airstreams in extratropical cyclones, so-called warm conveyor belts (WCBs), modulate the upper-tropospheric Rossby wave pattern and are sources and magnifiers of forecast uncertainty. Thus, from a process-oriented perspective, numerical weather prediction (NWP) and climate models should adequately represent WCBs. The identification of WCBs usually involves Lagrangian air parcel trajectories that ascend from the lower to the upper troposphere within 2 d. This requires expensive computations and numerical data with high spatial and temporal resolution, which are often not available from standard output. This study introduces a novel framework that aims to predict the footprints of the WCB inflow, ascent, and outflow stages over the Northern Hemisphere from instantaneous gridded fields using convolutional neural networks (CNNs). With its comparably low computational costs and relying on standard model output alone, the new diagnostic enables the systematic investigation of WCBs in large data sets such as ensemble reforecast or climate model projections, which are mostly not suited for trajectory calculations. Building on the insights from a logistic regression approach of a previous study, the CNNs are trained using a combination of meteorological parameters as predictors and trajectory-based WCB footprints as predictands. Validation of the networks against the trajectory-based data set confirms that the CNN models reliably replicate the climatological frequency of WCBs as well as their footprints at instantaneous time steps. The CNN models significantly outperform previously developed logistic regression models. Including time-lagged information on the occurrence of WCB ascent as a predictor for the inflow and outflow stages further improves the models' skill considerably. A companion study demonstrates versatile applications of the CNNs in different data sets including the verification of WCBs in ensemble forecasts. Overall, the diagnostic demonstrates how deep learning methods may be used to investigate the representation of weather systems and their related processes in NWP and climate models in order to shed light on forecast uncertainty and systematic biases from a process-oriented perspective.

Toward a Systematic Evaluation of Warm Conveyor Belts in Numerical Weather Prediction and Climate Models. Part II: Verification of Operational Reforecasts

AbstractWarm conveyor belts (WCBs) associated with extratropical cyclones transport air from the lower troposphere into the tropopause region and contribute to upper-level ridge building and the formation of blocking anticyclones. Recent studies indicate that this constitutes an important source and magnifier of forecast uncertainty and errors in numerical weather prediction (NWP) models. However, a systematic evaluation of the representation of WCBs in NWP models has yet to be determined. Here, we employ the logistic regression models developed in Part I to identify the inflow, ascent, and outflow stages of WCBs in the European Centre for Medium-Range Weather Forecasts (ECMWF) subseasonal reforecasts for Northern Hemisphere winter in the period January 1997 to December 2017. We verify the representation of these WCB stages in terms of systematic occurrence frequency biases, forecast reliability, and forecast skill. Systematic WCB frequency biases emerge already at early lead times of around 3 days with an underestimation for the WCB outflow over the North Atlantic and eastern North Pacific of around 40% relative to climatology. Biases in the predictor variables of the logistic regression models can partially explain these biases in WCB inflow, ascent, or outflow. Despite an overconfidence in predicting high WCB probabilities, skillful WCB forecasts are on average possible up to a lead time of 8–10 days with more skill over the North Pacific compared to the North Atlantic region. Our results corroborate that the current limited forecast skill for the large-scale extratropical circulation on subseasonal time scales beyond 10 days might be tied to the representation of WCBs and associated upscale error growth.

Impact of Nifty Bees on Select Gold Exchange Funds with Reference to NSE India

The growth of exchange traded funds in India is in ascent stage. Investors who cont take the advantage with direct investments they can take the ETF’S help. The investment spectrum of ETF’S is increasing day by day. In this study how sectorial indices are affecting the ETF’S for the period of 2016 to 2021. The study measured the relationship of select Gold ETFs with the Nifty BeES by applying the vector error correction model. The study result reveals that all the selected ETFs are having the significant relationship with the Nifty BeES. The Ordinary least square method has been used to know the impact of Nifty BeES on the select Gold ETFs and observed that all the Gold ETFs are having the significant impact by the benchmark of NSE India Nifty BeES. This paper is useful to the investors of ETF, mutual funds and regulators of the capital market.

Rate-dependent input curve shaping of the piezoelectric actuator based optical resonator cavity displacement characteristics for an external cavity diode laser.

In an external cavity diode laser, the rate-dependent nonlinearity of the piezoelectric actuator based optical resonator cavity (ORC) restricts its application in high-precision measurements. This paper proposes a rate-dependent nonlinear active suppression method for an ORC system based on the Hammerstein model. Using a back propagation neural network and system identification algorithm, a high-precision rate-dependent Hammerstein model of the ORC system is established. The B-spline curve is used to simplify the input voltage curve, and the optimized voltage curve that can obtain the linear displacement output is solved by the particle swarm optimization algorithm. The experimental results show that in the frequency range of 2-50Hz, the regression coefficients (R2) of the ascent and descent stages at each experimental frequency of the ORC system increased to over 0.9998 and optimized the curve at the inflection pointto suppress the vibration at the inflection point.

Long-term orbit stability of the Apollo 11 “Eagle” Lunar Module Ascent Stage

The Apollo 11 “Eagle” Lunar Module ascent stage was abandoned in lunar orbit after the historic landing in 1969. Its fate is unknown. Numerical analysis described here provides evidence that this object might have remained in lunar orbit to the present day. The simulations show a periodic variation in eccentricity of the orbit, correlated to the selenographic longitude of the apsidal line. The rate of apsidal precession is correlated to eccentricity. These two factors appear to interact to stabilize the orbit over the long term.

Methodology and Results of Optimizing the Ascent Stage in the Problem of Vertical Navigation of Civil and Military Transport Aircraft

Methodology and Results of Optimizing the Ascent Stage in the Problem of Vertical Navigation of Civil and Military Transport Aircraft

The microstructure and tribological properties of M50 steel surface after titanium ion implantation

Titanium ions with different energies and doses were implanted into the M50 steel surface. In addition, titanium and nitrogen ion co-implantation was applied for comparison. The tribological properties and wear resistance of the implanted samples were characterized using a sliding friction tester, grazing incidence angle X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, surface profiler, Raman spectrometer, and nanoindentation tests. The results indicated that the compounds of the titanium ion–implanted samples mainly consisted of titanium and TiO2, CrN interstitial compounds formed after titanium and nitrogen ion co-implantation, thus generating an implantation layer that exhibited high nano-hardness and low wear rates. The linear contact sliding friction coefficient curves for the implantation samples were composed of an initial stage, ascent stage, and stable stage. The tribological properties effectively improved with increasing titanium ion implantation energies and doses. In addition, this beneficial effect became much more significant at a higher titanium ion dose. The titanium and nitrogen ion–co-implanted samples formed Fe2O3 and Fe3O4 tribo-oxide layers after the wear test, which were partially responsible for reducing the wear. The dominant wear mechanisms of the implanted samples were abrasive wear and oxidative wear.

How do humans recognize and face challenges of microplastic pollution in marine environments? A bibliometric analysis.

Microplastics (MPs) are abundant in marine environments, drawing global attention from scientists and rendering it significant to review the research progress and predict future trends of this field. To achieve that, we collected 1898 publications on marine MPs from Web of Science and performed a bibliometric analysis by CiteSpace and VOSviewer. Additionally, we utilized an unrestricted retrieval of literature from ScienceDirect to supplement our major findings. Trends in publication numbers show the growth in study from the initial stage ( 2012 and before), when microplastic (MP) occurrence, abundance, and distribution were primarily investigated. Throughout the ascent stage (between 2013-2016), when diverse sampling and analytical methods were applied to capture and identify MPs from the ocean, baseline data have been gleaned on physiochemical properties of MPs. The research focus then shifted to the bioaccumulation and ecotoxicological effects of MPs on marine biota, further highlighting their potential deleterious impacts on human health via dietary exposure, and this period was defined as the exploration stage (2017 and onwards). Nevertheless, key challenges including the lack of standard procedures for MP sampling, technical limitations in MP detecting and identification, and controversy about the underlying effects on the marine ecosystems and humans have also been arisen in the last decade. The present study elucidates how we gradually recognize MP pollution in marine environments and what challenges we face, suggesting future avenues for MP research.

Technological innovation in libraries

PurposeThe purpose of this study was to identify technological innovation in libraries and further examine the knowledge source and their effects during the technology life cycle (TLC).Design/methodology/approachThis paper discusses the technological innovation taking place in libraries. Patent citation analysis was used to capture the trend of technological innovation associated with libraries.FindingsThe findings are as follows: (1) library technologies are now in the ascent phase of their life cycles; (2) private companies from the United States, Germany, France, Japan and the United Kingdom are the top-five owners of intellectual property rights associated with library technology and (3) patent data along with knowledge and technology indicators can be interpreted in the light of library development. The knowledge source with the highest degree of scientific and technological orientation was identified as basic material chemistry. The major technological categories that have received the greatest knowledge effect from library-associated technological innovation are chemistry, electrical engineering, instruments, mechanical engineering, with other fields (civil engineering and furniture, games) being subject to less effect.Research limitations/implicationsThere are two research limitations in this study. First, the results use single informants, patents retrieved from United States Patent and Trademark Office, as the source of data. Second, this study uses patent citation measures for exploring the knowledge source and effect of technological innovation, these measures are only subjective for those new invention highly based technological advances. This study concludes that technological innovation for libraries will be characterized by an increasing role for science-intensive and interdisciplinary areas. This study also suggests that organizational learning facilitates innovation. Therefore, a library hoping to co-evolve with dynamic environment through technological innovation should improve its organizational learning processes.Practical implicationsTheories of technology-push and demand-pull were examined in relation to technological innovation taking place in libraries. The TLC analysis indicated that library technology is mainly in the ascent stage, suggesting that libraries have not achieved the strongest technological transformation. The findings suggest that the importance of demand-pull and technology-push vary over the TLC of libraries.Social implicationsTo survive in a dynamic environment library must be able to cope with increasing complexity and high-speed technological change. It is pivotal to integrate the views of users (as customers), software houses or design companies (as suppliers) as well as other libraries (as communities) into the sustainable development strategy of a library. In these contexts, libraries with the capacity to innovate will be able to respond to new demands faster and to invent and provide new services better than noninnovative libraries.Originality/valueAnalysis based on the technological innovation perspective to identify the future development of libraries is still lacking. This paper seeks to identify the technological innovation employed in libraries to accommodate the 21st century model of information-seeking behavior. This study identifies a variety of factors that have influenced the transformation of library services, and these include technology developments and new demands from library users. To illustrate the driving forces of technology-push in libraries, this paper examines holistic-patented technologies invented for libraries.

Study on the dynamic characteristics of rock surrounding a wellbore in energy storage areas during deep geothermal energy mining.

Based on the engineering background in which the rock surrounding a wellbore is affected by a thermal shock, impact disturbances from drilling vibration, cyclic heat extraction and high temperature during hydrothermal geothermal energy mining, the environmental conditions in the shaft wall rock are simulated by means of high temperature, cooling, immersing granite in water with different curing temperatures and applying impact loads. Additionally, an experimental study on the mechanical characteristics of circular granite specimens under radial impact loads and in the heat treatment and water curing conditions is carried out. The results show that the inner diameters of the rings, heating temperatures, curing water temperatures and cycle heating times are less affected than other parameters by the impact load-strain curves of circular granite, which can generally be divided into three sections, i.e., the initial straight stage, nonlinear ascent yield stage and post-peak nonlinear decline stage. The factors in the test weaken the capacity of the circular granite to resist the impact, but the sizes of the inner diameters of the rings play a leading role. Dynamic tensile strain is generated in the inner wall along the impact direction during the impact, while compressive strain is produced on the inner wall in the vertical impact loading direction. By analysing the crack propagation and final failure mode of circular granite, it is found that dynamic tensile failures are generated, crack initiation starts from the inner wall along the impact loading direction, and the outer circle in the vertical direction lags behind. The crack starts early and develops quickly on one side of the transmission bar. Finally, the failure criterion is established on the basis of some assumptions and circular-granite deformation failure characteristics, and the parameters, measured by the Brazilian disk test, are reasonably verified via substitution into the failure criterion equation.