Mass Redistribution Research Articles

Modeling the gravitational effects of ocean tide loading at coastal stations in the China earthquake gravity network based on GOTL software

Abstract The gravitational effects of ocean tide loading, which are one of the main factors affecting gravity measurements, consist of three components: (1) direct attraction from the tidal water masses, (2) radial displacement of the observing station due to the tidal load, and (3) internal redistribution of masses due to crustal deformation. In this study, software for gravitational effects of ocean tide loading was developed by evaluating a convolution integral between the ocean tide model and Green’s functions that describe the response of the Earth to tide loading. The effects of three-dimensional station coordinates, computational grid patterns, ocean tide models, Green’s functions, coastline, and local tide gauge were comprehensively considered in the programming process. Using a larger number of high-precision coastlines, ocean tide models, and Green’s functions, the reliability and applicability of the software were analyzed at coastal stations in the China Earthquake Gravity Network. The software can provide the amplitude and phase for ocean tide loading and produce a predicted gravity time series. The results can effectively reveal the variation characteristics of ocean tide loading in space and time. The computational gravitational effects of ocean tide loading were compared and analyzed for different ocean tide models and Green’s functions. The results show that different ocean tide models and Green’s functions have certain effects on the calculated values of loading gravity effects. Furthermore, a higher-precision local ocean tide model, digital elevation model, and local tidal gauge record can be further imported into our software to improve the accuracy of loading gravity effects in the global and local zones. The software is easy to operate and can provide a comprehensive platform for correcting the gravitational effects of ocean tide loading at stations in the China Earthquake Gravity Network.

On Two Formulations of Polar Motion and Identification of Its Sources

Differences in formulation of the equations of celestial mechanics may result in differences in interpretation. This paper focuses on the Liouville-Euler system of differential equations as first discussed by Laplace. In the “modern” textbook presentation of the equations, variations in polar motion and in length of day are decoupled. Their source terms are assumed to result from redistribution of masses and torques linked to Earth elasticity, large earthquakes, or external forcing by the fluid envelopes. In the “classical” presentation, polar motion is governed by the inclination of Earth’s rotation pole and the derivative of its declination (close to length of day, lod). The duration and modulation of oscillatory components such as the Chandler wobble is accounted for by variations in polar inclination. The “classical” approach also implies that there should be a strong link between the rotations and the torques exerted by the planets of the solar system. Indeed there is, such as the remarkable agreement between the sum of forces exerted by the four Jovian planets and components of Earth’s polar motion. Singular Spectral Analysis of lod (using more than 50 years of data) finds nine components, all with physical sense: first comes a “trend”, then oscillations with periods of ∼80 yrs (Gleissberg cycle), 18.6 yrs, 11 yrs (Schwabe), 1 year and 0.5 yr (Earth revolution and first harmonic), 27.54 days, 13.66 days, 13.63 days and 9.13 days (Moon synodic period and harmonics). Components with luni-solar periods account for 95% of the total variance of the lod. We believe there is value in following Laplace’s approach: it leads to the suggestion that all the oscillatory components with extraterrestrial periods (whose origin could be found in the planetary and solar torques), should be present in the series of sunspots and indeed, they are.

Theoretical Investigation of Selection (Calculation) of Design Parameters of Modular Draft Device in Aggregation of Semitrailers

One of the directions for expanding the functional properties of modular draft devices (MDD) is their use with semitrailers (using a fifth-wheel coupling, installed on the technological module). The issue with this is due to their ability to create such a redistribution of the MDD operational mass along the semitrailer’s axles whereby the loss of control of the entire transport aggregate is possible. To solve this problem, regularities have been established to consider in choosing the design parameters of the MDD. It has been established by theoretical calculations that an increase in the angle of inclination of the central α, with negative values of the angle of inclination of the lower β links of the rear-mounted mechanism of the MDD’s power module (PM), leads to an increase in the vertical load of the wheels of its technological module. The transition of the longitudinal coordinate point of the semitrailer’s tractive resistance application from −0.30 m to +0.30 m, provided α > β, leads to an increase in the vertical load on the wheels of its technological module. Increasing the angles of inclination of the central and lower links of the rear linkage of the PM leads to an increase in the vertical load on the wheels of its front axle. An exception is the option in which the lower links of the specified linkage mechanism are set at a negative angle at the level of −10°. An increase in the value of the angle of inclination of the central value, with positive values of the angle of inclination of the lower links of the rear-mounted mechanism of the PM, and compliance with the condition α < β, leads to a decrease in the vertical load of the wheels of the technological module.

Transient nuclear criticality excursion analysis of highly dispersed particulate three-phase fluidised systems

The aim of this study was to perform sensitivity analysis, investigating how different fluidisation and sedimentation characteristics of three-phase wetted UO2 powder beds, may affect a transient nuclear criticality excursion initiated through the addition of water into a fissile powder bed. This type of postulated nuclear criticality accident scenario may occur in nuclear fuel fabrication facilities when a fire is fought through the use of water, supplied via an automatic or manual fire-suppression system. A similar scenario may also develop as a result of water leaks or flooding of the process area housing UO2 powder. The article introduces a model for gas-bubble induced fluidisation of a UO2 powder bed and examines how this phenomenon may affect the neutron kinetic response of a three-phase fluidised fissile powder system. Empirical analysis has shown that fissile suspensions form agglomerated structures when suspended in water, at agglomerate sizes that range from 18 μm to 40 μm. Simulation results indicate that both the critical gas velocity and rate of fluidisation may significantly affect transient nuclear criticality excursion dynamics. The re-distribution of fissile mass into a highly dispersed suspension generally reduces the reactivity of the system, however, depending on the H/U ratio, a positive reactivity may be added to the system. Low Péclet numbers in the suspension suggest that gas-bubble induced motion of the suspension causes a highly dispersive flow field. An oscillatory power response is predicted for low critical gas velocities where the reactivity of the system is predominantly governed by the re-distribution of fissile mass within the system. The frequency of these oscillations is greater for a higher hindered settling rate of powder particles. At a higher critical gas velocity, the transient nuclear criticality excursion is governed by the voidage reactivity feedback, making the response quite independent of fluidisation. In all cases, large volumes of UO2 powder may leave the domain due to overflowing of the suspension. Transient nuclear criticality excursions in UO2 powder beds with a low critical gas velocity are terminated once the bed becomes fully saturated.

A combination of tides and nontidal variations in ocean bottom pressure may generate interannual slip fluctuations in the transition zone along a subduction plate interface

The tidal triggering of earthquakes has been studied for many years. The discovery of slow earthquakes in the early 2000s, including slow slip, has urged scientists to investigate the tidal responses of these earthquakes due to their sensitivity to weak stress perturbations. Previous studies have shown that slow earthquakes correlate with diurnal and semidiurnal tides and seasonal variations in surface loads more clearly than ordinary earthquakes. However, little is known about long-term responses to external stresses. In this paper, based on a widely accepted frictional law for faults, a mechanism is proposed by which nontidal variations in ocean bottom pressure, when combined with tides, promote the occurrence of slow earthquakes. Because slow earthquakes accompany a slip on the plate interface, this mechanism allows one to estimate slip modulations. A one-degree-of-freedom slip model is constructed and applied to Ise Bay in the Tonankai region of southwestern Japan, where large-scale ocean mass redistributions have occurred. The model calculated with parameters determined from the observation of tectonic tremors is quantitatively consistent with the slip during 1997–2013 inferred from GNSS data, suggesting that the decrease in the sea-level change in approximately 2006 could cause the acceleration of a slip observed after that. This result implies that the decreases in sea level in approximately 1996 and 2014 could also cause subsequent slip accelerations. These three slip acceleration periods temporally coincide with the increases in background seismicity in a shallower portion of the plate interface. These changes in seismicity are common to shallow earthquakes in the Tokai area, and a similar model can reproduce them. Further studies are expected to reveal causality between shallow earthquakes and long-term slip fluctuations based on modeling that considers changes in the frictional property along the plate interface.

Trends and uncertainties of mass-driven sea-level change in the satellite altimetry era

Abstract. Ocean mass change is one of the main drivers of present-day sea-level change (SLC). Also known as barystatic SLC, ocean mass change is caused by the exchange of freshwater between the land and the ocean, such as melting of continental ice from glaciers and ice sheets, and variations in land water storage. While many studies have quantified the present-day barystatic contribution to global mean SLC, fewer works have looked into regional changes. This study provides an analysis of regional patterns of contemporary mass redistribution associated with barystatic SLC since 1993 (the satellite altimetry era), with a focus on the uncertainty budget. We consider three types of uncertainties: intrinsic (the uncertainty from the data/model itself), temporal (related to the temporal variability in the time series) and spatial–structural (related to the spatial distribution of the mass change sources). Regional patterns (fingerprints) of barystatic SLC are computed from a range of estimates of the individual freshwater sources and used to analyze the different types of uncertainty. Combining all contributions, we find that regional sea-level trends range from −0.4 to 3.3 mm yr−1 for 2003–2016 and from −0.3 to 2.6 mm yr−1 for 1993–2016, considering the 5–95th percentile range across all grid points and depending on the choice of dataset. When all types of uncertainties from all contributions are combined, the total barystatic uncertainties regionally range from 0.6 to 1.3 mm yr−1 for 2003–2016 and from 0.4 to 0.8 mm yr−1 for 1993–2016, also depending on the dataset choice. We find that the temporal uncertainty dominates the budget, responsible on average for 65 % of the total uncertainty, followed by the spatial–structural and intrinsic uncertainties, which contribute on average 16 % and 18 %, respectively. The main source of uncertainty is the temporal uncertainty from the land water storage contribution, which is responsible for 35 %–60 % of the total uncertainty, depending on the region of interest. Another important contribution comes from the spatial–structural uncertainty from Antarctica and land water storage, which shows that different locations of mass change can lead to trend deviations larger than 20 %. As the barystatic SLC contribution and its uncertainty vary significantly from region to region, better insights into regional SLC are important for local management and adaptation planning.

Steerable directional bouncing and contact time reduction of impacting droplets on superhydrophobic stepped surfaces

HypothesisThe unbalanced capillary force provided by wettability patterns, non-uniform/asymmetric microtextures enables directional droplet transport, while macrotextures have shown potentials in reducing the contact time. Inspired by these findings, we design millimeter superhydrophobic stepped surfaces to simultaneously achieve highly steerable directional bouncing and contact time reduction of impacting droplets. ExperimentsThe stepped surfaces are fabricated by computerized numerical control, chemical oxidation, hydrophobic treatment. Systematic impact experiments are conducted under Weber number ranging from 10.5 to 20.5, two step heights (0.5 mm and 1.0 mm) and extensive impact positions. FindingsCompared with known microtextured surfaces, the stepped surfaces exhibit excellent performance with the maximum lateral movement distance about 8 times of droplet radius, controllable rebound angle ranging from ∼ 32° to ∼ 90° and up to ∼ 30 % reduction in contact time. Particularly, we divide the directional bouncing characteristics into six regimes and attribute the variation of rebound velocity by the synergistic effects of viscous dissipation, excess surface energy, excess kinetic energy. It is demonstrated that the contact time is reduced by liquid mass redistribution and asymmetry enhancement. Predictive models of contact time that incorporate the coupling effects of impact position, impact velocity and step height are also established.

Incorporating baryon-driven contraction of dark matter halos in rotation curve fits

The condensation of baryons within a dark matter (DM) halo during galaxy formation should result in some contraction of the halo as the combined system settles into equilibrium. We quantify this effect on the cuspy primordial halos predicted by DM-only simulations for the baryon distributions observed in the galaxies of the SPARC database. We find that the DM halos of high surface brightness galaxies (with Σeff ≳ 100 L⊙ pc−2 at 3.6 μm) experience strong contraction. Halos become more cuspy as a result of compression: the inner DM density slope increases with the baryonic surface mass density. We iteratively fit rotation curves to find the balance between initial halo parameters (constrained by abundance matching), compression, and stellar mass-to-light ratio. The resulting fits often require lower stellar masses than expected for stellar populations, particularly in galaxies with bulges: stellar mass must be reduced to make room for the DM it compresses. This trade off between dark and luminous mass is reminiscent of the cusp-core problem in dwarf galaxies, but occurs in more massive systems: the present-epoch DM halos cannot follow from cuspy primordial halos unless (1) the stellar mass-to-light ratios are systematically smaller than expected from standard stellar population synthesis models, and/or (2) there is a net outward mass redistribution from the initial cusp, even in massive galaxies widely considered to be immune from such effects.

Bayesian modelling of piecewise trends and discontinuities to improve the estimation of coastal vertical land motion

One of the major sources of uncertainty affecting vertical land motion (VLM) estimations are discontinuities and trend changes. Trend changes are most commonly caused by seismic deformation, but can also stem from long-term (decadal to multidecadal) surface loading changes or from local origins. Although these issues have been extensively addressed for Global Navigation Satellite System (GNSS) data, there is limited knowledge of how such events can be directly detected and mitigated in VLM, derived from altimetry and tide-gauge differences (SATTG). In this study, we present a novel Bayesian approach to automatically and simultaneously detect such events, together with the statistics commonly estimated to characterize motion signatures. Next to GNSS time series, for the first time, we directly estimate discontinuities and trend changes in VLM data inferred from SATTG. We show that, compared to estimating a single linear trend, accounting for such variable velocities significantly increases the agreement of SATTG with GNSS values (on average by 0.36 mm/year) at 339 globally distributed station pairs. The Bayesian change point detection is applied to 606 SATTG and 381 GNSS time series. Observed VLM, which is identified as linear (i.e. where no significant trend changes are detected), has a substantially higher consistency with large-scale VLM effects of glacial isostatic adjustment (GIA) and contemporary mass redistribution (CMR). The standard deviation of SATTG (and GNSS) trend differences with respect to GIA+CMR trends is by 38% (and 48%) lower for time series with constant velocity compared to variable velocities. Given that in more than a third of the SATTG time series variable velocities are detected, the results underpin the importance to account for such features, in particular to avoid extrapolation biases of coastal VLM and its influence on relative sea-level-change determination. The Bayesian approach uncovers the potential for a better characterization of SATTG VLM changes on much longer periods and is widely applicable to other geophysical time series.

Recovering Regional Groundwater Storage Anomalies by Combining GNSS and Surface Mass Load Data: A Case Study in Western Yunnan

The redistribution of surface mass (e.g., atmosphere, soil water, oceans, and groundwater) can cause load responses, resulting in vertical deformations of the crust. Indeed, the global navigation satellite system (GNSS)-based continuously operating reference stations (CORS) are able to accurately measure the vertical deformation caused by surface mass loads. In this study, the CORS was used to invert groundwater storage anomalies (GWSA), represented by the equivalent water height (EWH), after removing the effect of the non-groundwater surface mass load (atmospheric, groundwater, and non-tidal oceanic loads) from the vertical deformation monitored by CORS. In addition, the global and regional high-resolution surface mass models were combined to calculate the high-precision load deformation field in in western Yunnan using the remove–restore method, thereby obtaining more accurate surface mass load data and improving the accuracy of the inverted GWSA results. In order to assess the feasibility of the CORS inversion for the GWSA used, 66 CORS stations in western Yunnan Province were considered, presenting weekly GWSA data from 10 January 2018 to 31 December 2020. The results revealed significant seasonal variation in GWSA in the study area, showing an amplitude range of −200–200 mm. This approach is based on the already-established CORS network without requiring additional set-up costs. In addition, the reliability of CORS inverse results was assessed using Gravity Recovery and Climate Experiment (GRACE) inverse results and actual groundwater monitoring data. According to the obtained results, GWSA can be monitored by both CORS and GRACE data; however, CORS provided a more effective spatiotemporal resolution of GWSA. Therefore, the CORS network combined with surface mass load data is able to effectively monitor the spatiotemporal dynamics of GWSA in small-scale areas and provides important references for the study of hydrology.

Passive Tomographic Study on Velocity Changes in Underground Mines Using Tabular Mesh Grids

Abstract Double difference tomographic inversion on measurements of travelling time and location are performed to analyze the velocity structure within rock mass in underground mining. Residuals of each iteration are estimated to evaluate the conversion of computation. Average wave propagation velocities in tabular areas are assessed to compare the velocity change affected by mainshocks. It is summarized that velocity increases before mainshocks and then reduces with temporal evolution after them. Possible explanations include static stress buildup that enhances the wave propagation before mainshocks and static stress reduction that weakens the waveform propagation. Additionally, wave propagation is attenuated by the dynamic-shaking induced fractures and ruptures within rock masses. Velocity change is shown to be of importance in assessing the stress redistribution and stability of rock masses. It is found that P-wave velocity increased by 1% ~5% before the occurrence of mainshocks. After the mainshocks, the velocity turned into decreasing and eventually dropped to a level that was even lower than the average level before the mainshocks. It can be inferred that stress increased and formed a stress concentration region before the mainshocks. The occurrence of mainshocks caused damage and stress relaxation in the rock mass, leading to a significant velocity decrease.

Mantle Viscosity Derived From Geoid and Different Land Uplift Data in Greenland

AbstractThe Earth's mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth's gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long‐wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio‐spectral analysis of the Earth's gravity field and the land uplift rate in order to find the GIA‐related gravity field. We used different land uplift data, that is, the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), gravity recovery and climate experiment (GRACE) and glacial isostatic adjustment (GIA) data, and also combined them using the Kalman filtering technique. Using different land uplift rates, one can obtain different GIA‐related gravity fields. As shown in this study, the mantle viscosities of 1.9 × 1022 Pa s and 7.8 × 1021 Pa s for a depth of 200–700 km are obtained using ICE‐6G (VM5a) model and the combined land uplift model, respectively, and the GIA‐related gravity potential signal.

Seismic Contributions to Secular Changes in Global Geodynamic Parameters

AbstractSecular changes in global geodynamic parameters (polar motion excitation, length of day, and J2, etc.) are significant to understand internal mass transport in the solid Earth system and surface geophysical fluids related to global climate. However, the glacial isostatic adjustment (GIA) and climate‐driven surface mass redistribution are insufficient to explain the origin. We are motivated to report the significance of seismic effect in the pursuit of understanding the budget of secular changes in geodynamic parameters. The seismic effect is comparable to the GIA effect and amounts to 20% or larger (up to 30%) of the observed secular changes in global geodynamic parameters. Therefore, the seismic effect must be treated as one key mechanism of driving secular changes in geodynamic parameters, which is critical to invert rheological structure, clarify internal dynamic processes, and reveal the physical evolution of the Earth.

Different Ice-shell Geometries on Europa and Enceladus due to Their Different Sizes: Impacts of Ocean Heat Transport

On icy worlds, the ice shell and subsurface ocean form a coupled system—heat and salinity flux from the ice shell induced by the ice-thickness gradient drives circulation in the ocean, and in turn, the heat transport by ocean circulation shapes the ice shell. Therefore, understanding the dependence of the efficiency of ocean heat transport (OHT) on orbital parameters may allow us to predict the ice-shell geometry before direct observation is possible, providing useful information for mission design. Inspired by previous works on baroclinic eddies, I first derive scaling laws for the OHT on icy moons, driven by ice topography, and then verify them against high-resolution 3D numerical simulations. Using the scaling laws, I am then able to make predictions for the equilibrium ice-thickness variation knowing that the ice shell should be close to heat balance. The ice shell on small icy moons (e.g., Enceladus) may develop strong thickness variations between the equator and pole driven by the polar-amplified tidal dissipation in the ice; in contrast, the ice shell on large icy moons (e.g., Europa, Ganymede, Callisto, etc.) tends to be flat due to the smoothing effects of the efficient OHT. These predictions are manifested by the different ice-evolution pathways simulated for Enceladus and Europa, considering the ice freezing/melting induced by ice dissipation, conductive heat loss, and OHT as well as the mass redistribution by ice flow.

Excitations of Seasonal Polar Motions Derived from Satellite Gravimetry and General Circulation Models: Comparisons of Harmonic and Inharmonic Analyses

Due to the conservation of global angular momentum, polar motion (PM) is dominated by global mass redistributions and relative motions in the atmosphere, oceans and land water at seasonal time scales. Thus, accurately measured PM data can be used to validate the general circulation models (GCMs) for the atmosphere, oceans and land water. This study aims to analyze geophysical excitations and observed excitations obtained from PM observations from both the harmonic and wavelet analysis perspectives, in order to refine our understanding of the geophysical excitation of PM. The geophysical excitations are derived from two sets of GCMs and a monthly gravity model combining satellite gravity data and some GCM outputs using the PM theory for an Earth model with frequency-dependent responses, while the observed excitation is obtained from the PM data using the frequency-domain Liouville’s equation. Our results show that wavelet analysis can reveal the time-varying nature of all excitations and identify when changes happen and how strong they are, while harmonic analysis can only show the average amplitudes and phases. In particular, the monthly gravity model can correct the mismodeled GCM outputs, while the Earth’s frequency-dependent responses provide us with a better understanding of atmosphere–ocean–land water–solid Earth interactions.

Assessment of the compaction effect and operational characteristics of a crawler tractor based on a rheological approach

BACKGROUND: At considering the issues of crawler tractors interaction with soil the determining factor is the time-varying impact of loads on the soil layer, its stressed and strained state, which, in turn, directly depends on its stress-strain properties. The properties assessment should be carried out with a rheological approach, which allows to explain many phenomena and processes and to develop new high technologies in terms of the criterion of minimizing the impact on the soil.
 AIMS: Studying the compacting ability of a crawler tractor in a configuration in various machine-tractor units, obtaining a curve for the effect of the traction load on the tractor hook, tractor speed and tractor mass redistribution over the lower track wheels on changes in soil compaction due to developing deformations, the coefficient of running resistance and skidding of the crawler-mounted mover.
 METHODS: The evoluation method for compaction impact of crawler-mounted mover on the soil layer was developed on the base of the previously constructed a general mathematical model for determining ways of reducing the compacting impact of crawler-mounted movers on the bearing surface, computer calculation programmes and the carried out assessment for the deformation development and changes of soil compaction under the crawler track.
 RESULTS: There are presented the simulation results of the process with an assessment of the developing dependences of the crawler tractor rut depth and its sliding on the travelling speed and on the displacement of the center of pressure at different loads on the hook, that obtained with the developed metod of analysis and the well-known theory of hereditary creep of elastic-visco-plastic materials. At the same time, the development of vertical and shear deformations of the soil layer in the area of lower track wheels impact is separately analyzed.
 The analysis of the constructed dependencies allows to identify a number of patterns for changes of compacting effect indicators of a crawler tractor on the soil with an assessment of the influence of the main design and technological parameters on them. It is established that taking into account the rheological characteristics of the soil layer and its state parameters permit significantly improve the accuracy of calculations for vertical and shear deformations of the soil layer and its final compaction after successive passes of the crawler lower track wheels. At the same time, the desired indicators behavior is ambiguously at passes of various lower track wheels.
 CONCLUSION: The conducted studies contribute to the optimal selection of parts for various machine-tractor units based on a specific crawler tractor, which perform the appropriate technological operations in certain conditions of work at specific parameters of the soil state.

Constraining the Internal Structures of Venus and Mars from the Gravity Response to Atmospheric Loading

The gravity fields of celestial bodies that possess an atmosphere are periodically perturbed by the redistribution of fluid mass associated with atmospheric dynamics. A component of this perturbation is due to the gravitational response of the body to the deformation of its surface induced by the atmospheric pressure loading. The magnitude of this effect depends on the relation between the loading and the response in terms of geopotential variations measured by the load Love numbers. In this work, we simulate and analyze the gravity field generated by the atmospheres of Venus and Mars by accounting for different models of their internal structure. By precisely characterizing the phenomena that drive the mass transportation in the atmosphere through general circulation models, we determine the effect of the interior structure on the response to the atmospheric loading. An accurate estimation of the time-varying gravity field, which measures the atmospheric contribution, may provide significant constraints on the interior structure through the measurement of the load Love numbers. A combined determination of tidal and load Love numbers would enhance our knowledge of the interior of planetary bodies, providing further geophysical constraints in the inversion of internal structure models.

Provision of allowance for the root and connecting rod necks and balancing of the forgings of the crankshaft of a heavy-duty vehicle

The article discusses the requirements for balancing crankshafts. The unbalanced mass of the crankshaft after machining should be oriented in a certain angular sector, which ensures the removal of material in the opposite phase along the end surface of the counterweights. The existing calculation methods provide the specified imbalance conditions only at the design stage of the crankshaft forging by sorting through combinations of geometric accuracy indicators within the fields of their tolerances with simultaneous calculation of the position of the unbalanced mass. The method provides the design position of the unbalanced mass, but does not extend to the forging manufacturing process. The article considers the practice of machining production of changing the position of the machining base, which ensures the redistribution of masses. unprocessed elements of counterweights and the hit of an unbalanced mass in a given angular sector. Changing the position of the processing base completely redistributes the allowance for the root and connecting rod necks, which is not taken into account in the process of hot volumetric stamping of crankshaft forgings. The article presents a calculation scheme that allows taking into account changes in the position of the machining base, as well as mathematical dependencies that allow, according to measurements from the extreme trunnions of the crankshaft forging, to simulate the distribution of the allowance for the root and connecting rod necks from the machining base. Mathematical dependencies allow you to select the value of the adjustment displacements of the stamping equipment and ensure that there is an allowance for all angular phases of the main and connecting rod necks of the crankshaft forging.

Investigating the ligand agonism and antagonism at the D2long receptor by dynamic mass redistribution

The signalling of the D2 receptor (D2R), a G protein-coupled receptor (GPCR), is a complex process consisting of various components. For the screening of D2R ligands, methods quantifying distinct second messengers such as cAMP or the interaction of the receptor with β-arrestin, are commonly employed. In contrast, a label-free biosensor technology like dynamic mass redistribution (DMR), where it is mostly unknown how the individual signalling pathways contribute to the DMR signal, provides a holistic readout of the complex cellular response. In this study, we report the successful application of the DMR technology to CHO-K1 cells stably expressing the human dopamine D2long receptor. In real-time kinetic experiments, studies of D2R reference compounds yielded results for agonists and antagonists that were consistent with those obtained by conventional methods and also allowed a discrimination between partial and full agonists. Furthermore, investigations on the signalling pathway in CHO-K1 hD2longR cells identified the Gαi/o protein as the main proximal trigger of the observed DMR response. The present study has shown that the DMR technology is a valuable method for the characterisation of putative new ligands and, due to its label-free nature, suggests its use for deorphanisation studies of GPCRs.

Changes in ice-surface debris, surface elevation and mass through the active phase of selected Karakoram glacier surges

Surge-type glaciers switch between phases of rapid and slow flow on timescales of a few years to decades. During the active surge phase, large volumes of ice are transported downglacier, creating distinct geomorphological signatures that reflect these dynamic events but ice and sediment transport remain poorly quantified. The impact of surge events, in comparison to non-surge activity, is also unclear. Here, we describe glacier-surface debris and elevation changes through surges on ten different Karakoram glaciers (Khurdopin, Drenmang, Kunyang, Braldu, Chong Kumdan II, Qiaogeli, Saxinitulu, Shakesiga, Skamri and North Crown). We use these data to characterise the surface geomorphological changes during the surges. We also calculate the mass redistribution during each of the surges and compare this to an estimate of overall glacier mass. Repeat geomorphological mapping shows that surface debris transport through the surges leads to widespread rearrangement of surface features, folding and the concentration of debris near glacier termini, confluences and margins. Ice and debris mass redistribution varies between 0.11 and 0.94 Gt per event and shows moderate correlation with total glacier volume (r2 = 0.57) and glacier length (r2 = 0.40). Mass change as a proportion of total glacier volume ranges from about 0.5 to 5% and is moderately correlated with total glacier volume (r2 = 0.43) but not glacier length (r2 = 0.10). The overall conclusion is that surge events in this region account for only a small proportion of overall mass transport, but have an important role in surface debris transport and redistribution, as well as glacier mass balance.