Resonances of the InSight Seismometer on Mars

2021 ◽  
Author(s):  
Kenneth Hurst ◽  
Lucile Fayon ◽  
Brigitte Knapmeyer-Endrun ◽  
Cedric Schmelzbach ◽  
Martin van Driel ◽  
...  
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Seismic Signals ◽  
Resonant Frequencies ◽  
Phase Measurements ◽  
The Earth ◽  
Further Development ◽  
Potential Use ◽  
Different Parts ◽  
Sensor Assembly

ABSTRACT The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) seismometer was deployed to the surface of Mars in December 2018–February 2019. The specific deployment conditions, which are very different from those of a standard broadband instrument on the Earth, result in resonances caused by different parts of the sensor assembly (SA) that are recorded by the seismometer. Here, we present and characterize the resonances known to be present in the SA and their causes to aid interpretation of the seismic signals observed on Mars. Briefly, there are resonances in the SA at about 2.9, 5.3, 9.5, 12, 14, 23–28, and 51 Hz. We discuss various methods and tests that were used to characterize these resonances, and provide evidence for some of them in data collected on Mars. In addition to their relevance for the high frequency analysis of seismic data from InSight, specifically for phase measurements near the resonant frequencies, the tests and observations described here are also of potential use in the further development of planetary seismometers, for example, for Mars, the Moon, or Europa.

Effects of incomplete parameterization on full-wavefield viscoelastic seismic data for petrophysical reservoir properties

Geophysics ◽  
2007 ◽  
Vol 72 (3) ◽  
pp. O9-O17 ◽  
Author(s):  
Upendra K. Tiwari ◽  
George A. McMechan
Keyword(s):  
Seismic Data ◽  
Input Data ◽  
Elastic Model ◽  
Quality Factors ◽  
Noise Levels ◽  
Reservoir Properties ◽  
Estimated Parameters ◽  
Model Parameterization ◽  
The Earth ◽  
Incomplete Model

In inversion of viscoelastic full-wavefield seismic data, the choice of model parameterization influences the uncertainties and biases in estimating seismic and petrophysical parameters. Using an incomplete model parameterization results in solutions in which the effects of missing parameters are attributed erroneously to the parameters that are included. Incompleteness in this context means assuming the earth is elastic rather than viscoelastic. The inclusion of compressional and shear-wave quality factors [Formula: see text] and [Formula: see text] in inversion gives better estimates of reservoir properties than the less complete (elastic) model parameterization. [Formula: see text] and [Formula: see text] are sensitive primarily to fluid types and saturations. The parameter correlations are sensitive also to the model parameterization. As noise increases in the viscoelastic input data, the resolution of the estimated parameters decreases, but the parameter correlations are relatively unaffected by modest noise levels.

scholarly journals Biguanide-Based Synthesis of 1,3,5-Triazine Derivatives with Anticancer Activity and 1,3,5-Triazine Incorporated Calcium Citrate Nanoparticles

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1028
Author(s):  
Monnaya Chalermnon ◽  
Sarocha Cherdchom ◽  
Amornpun Sereemaspun ◽  
Rojrit Rojanathanes ◽  
Tanatorn Khotavivattana
Keyword(s):  
Anticancer Activity ◽  
Cell Lines ◽  
Anticancer Agent ◽  
Drug Loading ◽  
Calcium Citrate ◽  
Colorectal Cancer Cell Lines ◽  
Triazine Derivatives ◽  
Further Development ◽  
Derivatives Of ◽  
Potential Use

Twelve derivatives of biguanide-derived 1,3,5-triazines, a promising class of anticancer agent, were synthesised and evaluated for their anticancer activity against two colorectal cancer cell lines—HCT116 and SW620. 2c and 3c which are the derivatives containing o-hydroxyphenyl substituents exhibited the highest activity with IC50 against both cell lines in the range of 20–27 µM, which is comparable to the IC50 of cisplatin reference. Moreover, the potential use of the calcium citrate nanoparticles (CaCit NPs) as a platform for drug delivery system was studied on a selected 1,3,5-triazine derivative 2a. Condition optimisation revealed that the source of citrate ions and reaction time significantly influence the morphology, size and %drug loading of the particles. With the optimised conditions, “CaCit-2a NPs” were successfully synthesised with the size of 148 ± 23 nm and %drug loading of up to 16.3%. Furthermore, it was found that the release of 2a from the synthesised CaCit-2a NPs is pH-responsive, and 2a could be control released under the acidic cancer environment. The knowledge from this study is perceptive for further development of the 1,3,5-triazine-based anticancer drugs and provide the platform for the incorporation of other drugs in the CaCit NPs in the future.

scholarly journals Assessing evidence for adaptive evolution in two hearing-related genes important for high-frequency hearing in echolocating mammals

2021 ◽  
Author(s):  
Hui Wang ◽  
Hanbo Zhao ◽  
Yujia Chu ◽  
Jiang Feng ◽  
Keping Sun
Keyword(s):  
Adaptive Evolution ◽  
Hair Cells ◽  
High Frequency ◽  
Phylogenetic Trees ◽  
Outer Hair Cells ◽  
Functional Domain ◽  
Coding Region ◽  
Selective Pressures ◽  
Wide Range ◽  
Different Parts

Abstract High-frequency hearing is particularly important for echolocating bats and toothed whales. Previously, studies of the hearing-related genes Prestin, KCNQ4, and TMC1 documented that adaptive evolution of high-frequency hearing has taken place in echolocating bats and toothed whales. In this study, we present two additional candidate hearing-related genes, Shh and SK2, that may also have contributed to the evolution of echolocation in mammals. Shh is a member of the vertebrate Hedgehog gene family and is required in the specification of the mammalian cochlea. SK2 is expressed in both inner and outer hair cells, and it plays an important role in the auditory system. The coding region sequences of Shh and SK2 were obtained from a wide range of mammals with and without echolocating ability. The topologies of phylogenetic trees constructed using Shh and SK2 were different; however, multiple molecular evolutionary analyses showed that those two genes experienced different selective pressures in echolocating bats and toothed whales compared to non-echolocating mammals. In addition, several nominally significant positively selected sites were detected in the non-functional domain of the SK2 gene, indicating that different selective pressures were acting on different parts of the SK2 gene. This study has expanded our knowledge of the adaptive evolution of high-frequency hearing in echolocating mammals.

scholarly journals Enhanced Cognitive Walkthrough: Development of the Cognitive Walkthrough Method to Better Predict, Identify, and Present Usability Problems

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Lars-Ola Bligård ◽  
Anna-Lisa Osvalder
Keyword(s):  
Medical Equipment ◽  
Development Process ◽  
Product Development Process ◽  
Infusion Pumps ◽  
Usability Problems ◽  
Cognitive Walkthrough ◽  
High Level ◽  
High Degree ◽  
Further Development ◽  
Potential Use

To avoid use errors when handling medical equipment, it is important to develop products with a high degree of usability. This can be achieved by performing usability evaluations in the product development process to detect and mitigate potential usability problems. A commonly used method is cognitive walkthrough (CW), but this method shows three weaknesses: poor high-level perspective, insufficient categorisation of detected usability problems, and difficulties in overviewing the analytical results. This paper presents a further development of CW with the aim of overcoming its weaknesses. The new method is called enhanced cognitive walkthrough (ECW). ECW is a proactive analytical method for analysis of potential usability problems. The ECW method has been employed to evaluate user interface designs of medical equipment such as home-care ventilators, infusion pumps, dialysis machines, and insulin pumps. The method has proved capable of identifying several potential use problems in designs.

scholarly journals XII. On the cause of the discrepancies observed by Mr. Baily with the Cavendish apparatus for determining the mean density of the earth

1847 ◽  
Vol 137 ◽  
pp. 217-229 ◽  
Keyword(s):  
Mathematical Theory ◽  
Full Account ◽  
Astronomical Society ◽  
Royal Astronomical Society ◽  
The Earth ◽  
Singular Source ◽  
The Mean ◽  
The Masses ◽  
Source Of Error ◽  
Different Parts

In the Fourteenth Volume of the Transactions of the Royal Astronomical Society will be found a full account of the Cavendish apparatus, and of the mode of experimenting followed by Mr. Baily. It will therefore not be necessary for me, in this place, to enter into any detail as to the different parts of the instrument, and the various precautions adopted in order to avoid that singular source of error 'currents of air in the torsion box arising from unequal temperature,’ which had been discovered by Cavendish. It will be sufficient for me to state that all the arrangements are of a highly satisfactory kind, and that I am of opinion that no aerial currents could have existed in the torsion box. The deduction of the mean density of the earth from the observed vibrations of the balls influenced by the torsion force and the attraction of the masses, is founded on a mathematical theory of the motion of the balls given by the Astronomer Royal, Mr. Airy ; and as this theory is certainly insufficient to account for the discrepancies, it will here be necessary to give a brief sketch of it.

scholarly journals Using Sentinel-1 SAR data to detect earth surface changes related to neotectonics in the Focșani basin (Eastern Romania)

2018 ◽  
Author(s):  
Nicusor Necula ◽  
Mihai Niculita ◽  
Mario Floris
Keyword(s):  
Opposite Direction ◽  
Seismic Data ◽  
High Density ◽  
Earth Surface ◽  
Sar Images ◽  
Ground Deformations ◽  
Geological Surveys ◽  
Triggering Conditions ◽  
Potential Use ◽  
Surface Changes

Ground deformations are the result of interactions between terrain and various processes. Their identification and monitoring becomes an important step as they can provide insights about Earth’s dynamics or process triggering conditions. This paper aims to show the potential use of Sentinel-1 SAR images to identify ground deformations induced by neotectonics. Hence, we applied PS-InSAR stacking technique on Sentinel-1 ascending dataset in the area of Focșani basin, Eastern Romania. High density of PS obtained in populated areas allows the detection of tectonic fractures. They are characterized by blocks movement in opposite direction with 5-10 mm/year. Detection of geologic lineaments using free Sentinel-1 data presents a great advantage for future geological surveys which permits a better delineation of tectonic accidents, especially where seismic data are not available.

scholarly journals Reservoir Characteristics of Buried-hill Draping Zone in L Oilfield, Offshore China

2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Yujuan Liu ◽  
Qianping Zhang ◽  
Bin Zheng ◽  
Jing Zhang ◽  
Zhaozhao Qu
Keyword(s):  
Seismic Data ◽  
Eastern China ◽  
Seismic Facies ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Sedimentary Characteristics ◽  
Reservoir Characteristics ◽  
Production Practices ◽  
Buried Hill ◽  
Different Parts

The reservoir in different parts of buried-hill draping zone is often quite different, so it is of great significance to clarify the reservoir characteristics for exploration and development. Based on core, well logging, seismic data and production data, reservoir characteristics of oil layer Ⅱ in the lower second member of Dongying Formation of L oilfield, Bohai Bay Basin, offshore eastern China are systematically studied. Analyses of seismic facies, well-seismic combination, paleogeomorphology, and sedimentary characteristics are carried out. Sediment source supply, lake level and buried hill basement geomorphology all contribute to reservoir quality. The research suggests that the different parts of buried-hill draping zone can be divided into four types. Reservoir thickness and physical properties vary. The area where the provenance direction is consistent with the ancient valley direction is a favorable location for the development of high-quality reservoirs. Under the guidance of the results, oilfield production practices in L oilfield offshore China are successful. Knowledge gained from study of L oilfield has application to the development of other similar fields.

Paper 14: Acoustic Detection of Cavitation

1966 ◽  
Vol 181 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I. S. Pearsall
Keyword(s):  
High Frequency ◽  
Critical Frequency ◽  
Low Frequency ◽  
Francis Turbine ◽  
Frequency Noise ◽  
Performance Tests ◽  
Acoustic Detection ◽  
Cavitation Noise ◽  
Further Development ◽  
Onset Of Cavitation

The onset of cavitation in a hydraulic machine can be determined visually and its effect on performance by performance tests. It would be convenient to have an alternative method that required neither transparent sections nor expensive tests. Initial tests have been made measuring noise over a frequency range of 20 c/s-20 kc/s in one-third octave bands, on a number of pumps and turbines. An accelerometer attached to the casing was used. The tests indicated that, generally, the onset of cavitation was accompanied by a rise in the high-frequency noise, whilst the low-frequency noise increased as the cavitation developed. A maximum of cavitation noise was reached before the efficiency and load fell off. In some cases difficulty was experienced because blade cavitation was drowned by noise caused by other cavitation, such as the vortex in a Francis turbine. It also appears that the noise following the onset of cavitation is at the frequency which is used as a critical frequency in accelerated erosion tests. Further development of techniques is required, but the initial tests are encouraging.

A 108km2 Compressive Sensing Processing Trial

2021 ◽  
Author(s):  
Dustin Blymyer ◽  
Klaas Koster ◽  
Graeme Warren
Keyword(s):  
Compressive Sensing ◽  
Surface Waves ◽  
Seismic Data ◽  
High Frequency ◽  
Quality Data ◽  
Low Velocity ◽  
Conventional Design ◽  
Seismic Acquisition ◽  
Similar Cost ◽  
Station Density

Abstract Summary Compressive sensing (CS) of seismic data is a new style of seismic acquisition whereby the data are recorded on a pseudorandom grid rather than along densely sampled lines in a conventional design. A CS design with a similar station density will generally yield better quality data at a similar cost compared to a conventional design, whereas a CS design with a lower station density will reduce costs while retaining quality. Previous authors (Mosher, 2014) have shown good results from CS surveys using proprietary methods for the design and processing. In this paper we show results obtained using commercially available services based on published algorithms (Lopez, 2016). This is a necessary requirement for adoption of CS by our industry. This report documents the results of a 108km2 CS acquisition and processing trial. The acquisition and processing were specifically designed to establish whether CS can be used for suppression of backscattered, low velocity, high frequency surface waves. We demonstrate that CS data can be reconstructed by a commercial contractor and that the suppression of backscattered surface waves is improved by using CS receiver gathers reconstructed to a dense shot grid. We also show that CS acquisition is a reliable alternative to conventional acquisition from which high-quality subsurface images can be formed.

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