Gravimetric Work Research Articles

Estimate of the impact of storm microseisms on long-term gravimetric measurements

This study estimates the impact level of storm microseisms on long-term gravimetric measurements. Gravimetric measurements were conducted at the Zapolskoe, Obninsk, and Murmansk sites using CG-5 Autograv relative gravity meters. Seismic measurements were carried out concurrently with gravimetric measurements at Zapolskoe. The analysis of these measurements demonstrates the feasibility of utilizing seismic data as control information to estimate the high-frequency noise component of gravimetric data. Based on the additional seismic information from the services of the Incorporated Research Institutions for Seismology, the correspondence between the attenuation of the noise component in gravimetric measurements and the data from the modeled sensitive element of the gravimeter, which utilizes seismic series as an input, is identified. The first characterization of the storm-induced background noise of gravimetric measurements at the Murmansk site is obtained. Furthermore, the possibility of predicting measurement errors based on meteorological forecasts is refined, which can aid in the planning of gravimetric work.

GEOLOGICAL AND GEOTECTONIC UNITY OF THE DONETS BASIN AND THE DNIPROV-DONETS FALLS

On the basis of medium-scale mapping of the pre-Mesozoic surface of Donbas and the southeastern part of the DDZ, the use of the results of seismostratigraphic and gravimetric works, the analysis of scientific research, publications and innovative hypotheses, the geological and geotectonic unity of Donbas and the DDZ is substantiated. The features of the geological structure of the fringes and their central part were specified, and 16 alpine uplifts and downlifts of the northeastern trend were identified and mapped for the first time, including 5 drops in DDZ and 4 - in Donbass and 4 drops each to DDZ and Donbass.

Helical shape linen artificial muscles responsive to water

Artificial muscles, as the name suggests, can generate contractile force and movement from another source of energy in response to an external stimulus. Moisture-responsive artificial muscles can be manufactured from commodity natural fibers for smart textile applications taking advantage of the anisotropy, low cost and skin comfort of these fibers. Here we prepared water-driven artificial muscles by twisting linen yarns into spring-like cylindrical coils. Structural evolution, including increase in diameter and decrease in length of coils, is identified as a key factor to the actuation performances of the as-fabricated muscles. Artificial muscles with a single helical configuration can generate a large, reversible contraction stroke of about 22.5% and a high gravimetric work capacity during contraction of about 110 J kg−1 work capacity, which is many times greater than animal skeletal muscles and many synthetic fiber muscles. A torque-balanced double-helix muscle was constructed from the single helical muscle. The double helix showed good reversibility and high retention of contraction stroke (∼16.5%) in cyclic actuation tests. Finally, the as-fabricated water-responsive artificial muscles were used as manipulator arm of a miniature excavator.

Dual high-stroke and high-work capacity artificial muscles inspired by DNA supercoiling.

Powering miniature robots using actuating materials that mimic skeletal muscle is attractive because conventional mechanical drive systems cannot be readily downsized. However, muscle is not the only mechanically active system in nature, and the thousandfold contraction of eukaryotic DNA into the cell nucleus suggests an alternative mechanism for high-stroke artificial muscles. Our analysis reveals that the compaction of DNA generates a mass-normalized mechanical work output exceeding that of skeletal muscle, and this result inspired the development of composite double-helix fibers that reversibly convert twist to DNA-like plectonemic or solenoidal supercoils by simple swelling and deswelling. Our modeling-optimized twisted fibers give contraction strokes as high as 90% with a maximum gravimetric work 36 times higher than skeletal muscle. We found that our supercoiling coiled fibers simultaneously provide high stroke and high work capacity, which is rare in other artificial muscles.

ОПРЕДЕЛЕНИЕ ОПТИМАЛЬНЫХ ПАРАМЕТРОВ ДЛЯ ВЫЧИСЛЕНИЯ ПОПРАВОК ЗА РЕЛЬЕФ НА ОСНОВЕ ЦИФРОВЫХ МОДЕЛЕЙ РЕЛЬЕФА МЕСТНОСТИ (НА ПРИМЕРЕ ВОСТОЧНОГО ЗАБАЙКАЛЬЯ)

The study of corrections for the influence of terrain is a very popular and significant procedure in the production of high-precision gravimetric work. The results of such studies allow us to determine the optimal parameters for calculating terrain corrections, which helps to reduce the error in calculating the anomaly of the force of gravity in the Buge reduction and, accordingly, leads to an increase in the quality of the interpreted material. Therefore, the improvement of the methodology for calculating corrections for terrain is of particular interest for gravity exploration today and is a very relevant direction in high-precision surveying. Thus, in this article, the purpose of the study is to determine the optimal parameters for calculating terrain corrections for during high-precision gravimetric surveying. The degree of elaboration of the study indicates a number of unresolved issues, which are to some extent disclosed by the authors as a result of calculations and analysis of digital grids, graphs and other data involved in calculating terraincorrections. The article discusses the actual materials and methods for determining corrections for the influence of terrain, obtained during the production of high-precision field gravimetric work on one of the objects of the Trans-baikal Territory. In the course of the study, the results of determining the terraincorrections are presented, comparisons of the corrections in different zones are made, their quantitative indicators are analyzed, and statistics are provided. With the help of mathematical modeling, matrices (grids) of calculated parameters are constructed. The results of the study are clearly demonstrated in the diagrams and in the final tables, which indicates the reliability of the study performed. On the basis of the conducted research, conclusions are drawn and recommendations are made for the method of calculating corrections for the influence of terrain

Морфология Горихинского гранитного массива с помощью методов математической статистики

The Gorikhinsky granite massif is located in the marginal part of the Khentei highlands (Mongolian-Transbaikalian folded system, Central Mongolia). The massif is composed of coarse-grained weak-porphyry leucocratic granites, granite porphyry, and pegmatites. In the rocks of the massif, rock crystal deposits have been discovered. In certain pegmatite bodies, in addition to smoky quartz and morion crystals, the study has found the presence of fluorite, topaz, biotite, tourmaline, beryl, garnet, and allanite. The accessory minerals are cyrtolite, xenotime, zircon, sphene, rutile, apatite, cassiterite, etc. Thus, the study of the geological structure of the above object is of interest not only from a scientific but also from a practical point of view. The research data have become the basis for setting areal gravimetric work to determine the features of the massif’s geological structure. The work has been performed by the standard procedure using Scintrex Autograv CG-5 gravimeters. The height of the observation points has been determined by Trimble 5700 GPS devices. The RMS accuracy of the gravitational anomalies calculation as well as the density of the observation network meet the technical requirements for 1:100000 scale gravimetric surveys. Using the results of the gravity survey, a map of gravity anomalies in Bouguer has been compiled. Based on the interpretation of the map, with the use of the methods of mathematical statistics, quantitative characteristics of the shape and size of the body have been defined and a three-dimensional model of the massif has been built. For the purpose of the transformation and inversion of the gravitational field, the variance and regression methods of mathematical analysis have been used. The maximum thickness of the granites is 3.5 km; the area of the earth's surface projection is twice that of the granite outcrop. The obtained estimates are confirmed by the results of solving the inverse problem of gravimetry using the method of model selection. The article concludes that the use of the regression and variance analysis methods of mathematical statistics in the studies of the morphology of the intrusive bodies has proved most effective. The information on the shape and size of the massif will be used in concluding on the prospects of the massif’s metallogenic trend.

Shape memory nanocomposite fibers for untethered high-energy microengines.

Classic rotating engines are powerful and broadly used but are of complex design and difficult to miniaturize. It has long remained challenging to make large-stroke, high-speed, high-energy microengines that are simple and robust. We show that torsionally stiffened shape memory nanocomposite fibers can be transformed upon insertion of twist to store and provide fast and high-energy rotations. The twisted shape memory nanocomposite fibers combine high torque with large angles of rotation, delivering a gravimetric work capacity that is 60 times higher than that of natural skeletal muscles. The temperature that triggers fiber rotation can be tuned. This temperature memory effect provides an additional advantage over conventional engines by allowing for the tunability of the operation temperature and a stepwise release of stored energy.

TO DETERMINATION OF THE HEIGHTS ON GEODYNAMIC AND TECHNOGENIC POLYGONS

When performing high-precision geometric leveling on geodynamic and technogenic polygons, the problem of selecting a system of heights and obtaining reliable data arises, taking into account, first of all, the heterogeneity of the gravitational field along the lines of leveling. The research and development of a methodological approach to solve the above issues is the purpose of this publication. For the research process, the method of mathematical processing of a wide spectrum of geodetic and gravimetric measurements, differential and mathematical analysis, methods of conducting high-precision leveling and gravimetric works are used. During the process of field geodetic and gravimetric measurements, the values of gravitational acceleration in the mountain, foothill and plain areas were obtained, which made possible, on the basis of the mathematical dependences deduced by the author, to find corrections in the measured excesses for the non-parallelism of the level surfaces. On the basis of unique experimental level-gravimetric observations and their corresponding mathematical elaboration, numerical characteristics of gravitational acceleration for various forms of relief have been obtained. In the final case, the obtained analytic dependencies give an opportunity to take into account the influence of the non-parallelism of the level surfaces in the measured excesses or the heights of high-precision geometric leveling, without taking into account the gravitational field of the normal Earth. The proposed methodological approach to the determination of heights by high-precision geometric leveling on geodynamic and technogenic polygons may take into account the influence of the non-parallelism of the level surfaces according to the derived formulas and should be effectively used at present.

Electrochemically Powered, Energy-Conserving Carbon Nanotube Artificial Muscles.

While artificial muscle yarns and fibers are potentially important for many applications, the combination of large strokes, high gravimetric work capacities, short cycle times, and high efficiencies are not realized for these fibers. This paper demonstrates here electrochemically powered carbon nanotube yarn muscles that provide tensile contraction as high as 16.5%, which is 12.7 times higher than previously obtained. These electrochemical muscles can deliver a contractile energy conversion efficiency of 5.4%, which is 4.1 times higher than reported for any organic-material-based artificial muscle. All-solid-state parallel muscles and braided muscles, which do not require a liquid electrolyte, provide tensile contractions of 11.6% and 5%, respectively. These artificial muscles might eventually be deployed for a host of applications, from robotics to perhaps even implantable medical devices.

Stretchable artificial muscles from coiled polymer fibers

Abstract

Bio-inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn Muscles.

Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg−1), which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture driven muscle. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space.

Gravity field modelling and gravimetry

Abstract The summary of research activities concerning gravity field modelling and gravimetric works performed in Poland in the period of 2011-2014 is presented. It contains the results of research on geoid modelling in Poland and other countries, evaluation of global geopotential models, determination of temporal variations of the gravity field with the use of data from satellite gravity space missions, absolute gravity surveys for the maintenance and modernization of the gravity control in Poland and overseas, metrological aspects in gravimetry, maintenance of gravimetric calibration baselines, and investigations of the nontidal gravity changes. The bibliography of the related works is given in references.

The establishment of a new gravity reference frame for Serbia

In this paper, gravimetric work performed in the territory of Serbia is shown chronologically from the end of the nineteenth century until present. The first work, which was based on data from pendulums, is presented briefly. Details are provided on the establishment of the first order gravimetric network from 1952 and a basic gravimetric network created 10 years later. A review of a detailed gravimetric measurement, performed simultaneously with these works for establishing the networks, is also given. Special attention is dedicated to the first measurements using absolute gravimeters that were performed in 2007, but also to establishing a new basic gravimetric network as a basis for a future detailed gravimetric survey. From all of the shown data, it is to be noted that ex-Yugoslavia and then Serbia followed to a great extent modern trends of gravimetric network development. Unfortunately, the network maintenance was inadequate, and a database was not established due to the political and economic changes in the society, which caused suspension of some institutions that were authorised for these types of jobs.

Giant axial electrostrictive deformation in carbon nanotubes.

An exceptionally large axial electrostrictive deformation is demonstrated in single walled carbon nanotubes using Hartree-Fock and density functional quantum mechanics simulations. Armchair and zigzag open-ended tubes and capped tubes are studied and in all of them the external electric field induced axial strains can be greater than 10% for a field strength within 1 V/A. The corresponding volumetric and gravimetric work capacities are predicted to be three and six orders higher than those of the best known ferroelectric, electrostrictive, magnetostrictive materials and elastomers, respectively.

The permanent tide in GPS positioning

The treatment of the permanent tidal deformation of the Earth in GPS computation has been an almost unmentioned topic in the GPS literature. However, the ever increasing accuracy and the need to combine the GPS based coordinates with other methods requires a consistent way to handle the tides. Our survey shows that both the ITRF-xx coordinates and the GPS based coordinates are nowadays reduced to a “non-tidal” crust, conventionally defined using physically meaningless parameters. We propose to use instead the zero-crust concept which corresponds to concepts already accepted in the resolution of IAG in 1983 for gravimetric works.

AN EVALUATION STUDY OF THE CORRECT COMPUTATIONAL APPROACH FOR THE CONVERSION OF GRAVIMETRIC DATA FROM ONE REFERENCE DATUM TO ANOTHER

The major deficiencies besetting most gravimetric networks as a result of non-adherence to the use of the correct computational approach for the conversion of the gravity data from one reference datum to another are discussed. In order to evaluate the computational models developed for the correct conversion, a typical gravity network was used as a case study. Field observations were carried out at the same sites as had been used initially in observing the typical gravity network. Observations were tied to the nearby standard gravity network so as to calibrate and monitor the behaviour of the gravimeter used for the survey. Analysis of the data shows that there are flaws in the original data set. Typical values of corrections required at each site to convert the network to the IGSN 71 standard using the GRS 67 are obtained. Some recommendations that will aid the proper harmonisation of gravimetric data are given. It is concluded that gravimetric work of reasonable size should always be referred to a common datum via a standard reference gravity network. Whenever it is desirable to convert gravity data from one reference datum to another, the correct computational approach should be used.

AN EVALUATION STUDY OF THE CORRECT COMPUTATIONAL APPROACH FOR THE CONVERSION OF GRAVIMETRIC DATA FROM ONE REFERENCE DATUM TO ANOTHER

Abstract The major deficiencies besetting most gravimetric networks as a result of non-adherence to the use of the correct computational approach for the conversion of the gravity data from one reference datum to another are discussed. In order to evaluate the computational models developed for the correct conversion, a typical gravity network was used as a case study. Field observations were carried out at the same sites as had been used initially in observing the typical gravity network. Observations were tied to the nearby standard gravity network so as to calibrate and monitor the behaviour of the gravimeter used for the survey. Analysis of the data shows that there are flaws in the original data set. Typical values of corrections required at each site to convert the network to the IGSN 71 standard using the GRS 67 are obtained. Some recommendations that will aid the proper harmonisation of gravimetric data are given. It is concluded that gravimetric work of reasonable size should always be referred t...

Oxygen adsorption on polycrystalline cu films studied by means of gravimetric uptake and work function change

Oxygen adsorption on polycrystalline cu films studied by means of gravimetric uptake and work function change

A simple model of the crust and upper mantle in central Chile

abstract A simplified model of the crust and upper mantle of central Chile is developed with P- and S-wave arrival times and is compared with previous gravimetric work on the area. The following structural parameters were determined: crustal P-wave velocity, upper mantle P-wave velocity, crustal thickness and orientation of the plane separating crust and upper mantle. The model obtained here agrees well with those calculated in the gravimetric study.

THE STRUCTURE OF THE EARTH'S CRUST IN THE TRANSITIONAL AREA BETWEEN THE ASIAN CONTINENT AND THE PACIFIC OCEAN

Geophysical investigation in the Sea of Okhotsk, the Kuril-Kamchatka area, and the adjacent parts of the Pacific Ocean have been made to determine the crustal structure in the transitional zone between the Asian continent and Pacific Ocean. Seismic and gravimetric work show the MohoroviCiC surface at about 10 km on the oceanic side and gradual deepening toward the continent with a gentle gradient into the sea of Okhotsk. The first approximation of the Bouguer gravity anomaly relation is Hkm = 35 (1−th 0.0037 Δg), Hkm being the crustal thickness and Δg the Bouguer anomaly.--C. E. Sears.