scholarly journals A Mechanism of Variations of the Earth Rotation at Different Timescales

2000 ◽  
Vol 178 ◽  
pp. 373-379
Author(s):  
Yu. V. Barkin
Keyword(s):  
Polar Motion ◽  
Wide Spectrum ◽  
Slow Motion ◽  
Plate Motion ◽  
Triple Junctions ◽  
Geological Time ◽  
Time Intervals ◽  
New Approach ◽  
Mass Redistribution ◽  
Celestial Bodies

AbstractTo explain the observed effects in the Earth’s polar motion, a mechanism of the relative motion of the lower mantle and upper mantle with a boundary at 670 km of depth is proposed. According to the new approach, the Earth’s layers (including separate plates) are considered as nonspherical, heterogeneous celestial bodies, interacting with each other, with the Moon and the Sun and executing a wide spectrum of relative motions in different timescales. The small displacements of the centers of masses of the lower and upper mantles and their relative rotations have here a primary importance. These displacements display themselves at various time scales (from a few months to millions of years), and their manifestations are readily detected in the regularities of the distribution of geological structures as well as in many geodynamical processes. Important regularities of the ordered positions of the plate centers, of their triple junctions, hot spots, systems of fractures and cracks, geographic structures, fields of fossils, etc., are observed as consequences of certain displacements and inclined rotations (Barkin, 1999). At geological time intervals, the slow motion of the layers causes mutually correlated variations of the processes of rifting, spreading, subduction, regressions and transgressions of the sea, of the plate motion, formation and breakdown of super continents, etc. The motions and the accompanying tectonic mass redistribution cause variations of the components of the Earth’s inertia tensor and geopotential, which lead to variations of its diurnal rotation and polar motion. Explanation of the main properties of the perturbed Chandler polar motion has been done.

Patterns of Evolution of the Ediacaran Soft-Bodied Biota

2014 ◽  
Vol 88 (2) ◽  
pp. 269-283 ◽  
Author(s):  
Dmitriy Grazhdankin
Keyword(s):  
High Energy ◽  
Ecosystem Engineering ◽  
Low Energy ◽  
Geological Time ◽  
Time Intervals ◽  
Inner Shelf ◽  
Sedimentary Environments ◽  
Burrowing Activity ◽  
Ecological Associations ◽  
Channel Systems

When each of the Avalon-, Ediacara-, and Nama-type fossil assemblages are tracked through geological time, there appear to be changes in species composition and diversity, almost synchronized between different sedimentary environments, allowing a subdivision of the late Ediacaran into the Redkinian, Belomorian and Kotlinian geological time intervals. The Redkinian (580–559 Ma) is characterized by first appearance of both eumetazoan traces and macroscopic organisms (frondomorphs and vendobionts) in a form of Avalon-type communities in the inner shelf environment, whereas coeval Ediacara-type communities remained depauperate. The Belomorian (559–550 Ma) is marked by the advent of eumetazoan burrowing activity in the inner shelf, diversification of frondomorphs, migration of vendobionts from the inner shelf into higher energy environments, and appearance of tribrachiomorphs and bilateralomorphs. Ediacaran organisms formed distinctive ecological associations that coexisted in the low-energy inner shelf (Avalon-type communities), in the wave- and current-agitated shoreface (Ediacara-type communities), and in the high-energy distributary systems (Nama-type communities). The Kotlinian (550–540 Ma) witnessed an expansion of the burrowing activity into wave- and current-agitated shoreface, disappearance of vendobionts, tribrachiomorphs and bilateralomorphs in wave- and current-agitated shoreface, together with a drop in frondomorph diversity. High-energy distributary channel systems of prodeltas served as refugia for Nama-type communities that survived until the end of the Ediacaran and disappeared when the burrowing activity reached high-energy environments. This pattern is interpreted as an expression of ecosystem engineering by eumetazoans, with the Ediacaran organisms being progressively outcompeted by bilaterians.

scholarly journals Spent mushroom substrate: a crucial biosorbent for the removal of ferrous iron from groundwater

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
D. Menaga ◽  
S. Rajakumar ◽  
P. M. Ayyasamy
Keyword(s):  
Ferrous Iron ◽  
Tamil Nadu ◽  
Contaminated Water ◽  
Spent Mushroom Substrate ◽  
Pseudo First Order Reaction ◽  
Time Intervals ◽  
New Approach ◽  
First Order ◽  
Sorption Ability ◽  
Pseudo Second Order

Abstract A new approach was carried out with the spent mushroom substrate (SMS) of Pleurotus florida on ferrous iron (Fe2+) removal using live, dead and pretreated substrate. In this study, the various dosage levels of SMS namely, 0.25, 0.50, 1.0 and 1.50 g/50 mL were used for the removal of Fe2+ at different time intervals for 90 min. The effect of various temperatures and pH on Fe2+ removal was studied with optimized dosages and time intervals. The biosorption potential of P. florida SMS was checked against the iron-contaminated groundwater collected from in and around Salem, Namakkal and Dharmapuri districts of Tamil Nadu. The biosorption data were obtained and analyzed in terms of their kinetic behavior. Among the SMS of P. florida, the live SMS showed potential Fe2+ removal (100%) from aqueous metal solution in all the tested concentrations. SMS of P. florida showed high potential removal of Fe2+ in neutral pH, at room temperature and explored an efficient sorption ability (100%) in the tested water sample (SW10). The adsorption kinetic values fitted very well with pseudo-second-order when comparing with pseudo-first-order reaction. FTIR, SEM and EDX analysis proved the accumulation of Fe2+ by the SMS. The present study confirmed that the live SMS of P. florida may serve as a potential and eco-friendly biosorbent for removal of Fe2+ from the iron-contaminated water. Graphic abstract

scholarly journals Some Studies on Forming Optimization with Genetic Algorithm

2012 ◽  
Vol 2 (2) ◽  
pp. 105-112
Author(s):  
Ganesh Marotrao KAKANDIKAR ◽  
Vilas M. NANDEDKAR
Keyword(s):  
Genetic Algorithm ◽  
Process Parameters ◽  
Wide Spectrum ◽  
Simulation Software ◽  
Flow Conditions ◽  
Element Analysis ◽  
Blank Holder ◽  
New Approach ◽  
Finite Element Analysis Simulation ◽  
Selection Of

Forming is a compression-tension process involving wide spectrum of operations and flow conditions. The result of the process depends on the large number of parameters and their interdependence. The selection of various parameters is still based on trial and error methods. In this paper the authors presents a new approach to optimize the geometry parameters of circular components, process parameters such as blank holder pressure and coefficient of friction etc. The optimization problem has been formulated with the objective of optimizing the maximum forming load required in Forming. Genetic algorithm is used for the optimization purpose to minimize the drawing load and to optimize the process parameters. A finite element analysis simulation software Fast Form Advanced is used for the validations of the results after optimization.

scholarly journals A new research for the secular polar motion in this century

1988 ◽  
Vol 128 ◽  
pp. 385-392 ◽  
Author(s):  
Zhao Ming ◽  
Dong Danan
Keyword(s):  
North American ◽  
Polar Motion ◽  
Plate Motion ◽  
List Type ◽  
American Continent ◽  
Local Motion ◽  
New Techniques ◽  
North American Continent ◽  
The North ◽  
New Research

A new research for the secular drift of the Earth's pole was made based on nine long sequences of latitude observations and led to the following conclusions. 1.During this century, the Earth's pole has been moving with a mean rate of about 0″.0016/yr along the meridian about 70° (W). This drift rate is much less than the 0″.0035/yr derived from the ILS sequence.2.Relative to the North American continent, the Ukiah station located on the west coast of the U.S. shows a local drift of about 6 cm/yr northward, which coincides well with that determined by new techniques.3.Referring to the Europe-Asia plate, the whole North American continent shows a drift northward with a rate of about 8 cm/yr. The Mediterranian shows a similar drift of about 6 cm/yr. Perhaps these drifts are the consequences of plate motion and/or deflection of local vertical. It is useful for ascertaining the sources of the drifts to intercompare longer sequences observed with different techniques, including classical and new ones.4.Three of five ILS stations, Ukiah, Gaithersburg, and Carloforte, show significant local drifts. Therefore, the Conventional International Origin (CIO), which is defined by the 1903.0 mean latitudes of five ILS stations, is far from fixed on the Earth's surface. It is necessary to re-define an origin of the pole of the Conventional Terrestrial System (CTS).5.The quasi-30-year libration showed by the ILS data is not the real pattern of the Earth's polar motion, but results from both the irregular polar motion over some period and the local motion of Ukiah.

scholarly journals Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

2019 ◽  
Vol 15 (2) ◽  
pp. 539-554 ◽  
Author(s):  
Marcus P. S. Badger ◽  
Thomas B. Chalk ◽  
Gavin L. Foster ◽  
Paul R. Bown ◽  
Samantha J. Gibbs ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Ice Core ◽  
Co2 Uptake ◽  
Geological Time ◽  
Ocean Drilling Program ◽  
Time Intervals ◽  
Ocean Drilling ◽  
The Past ◽  
Global Carbon ◽  
Carbon System

Abstract. Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present, and future climate. Accurate and precise reconstructions of its concentration through geological time are therefore crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyr, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here, we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Pliocene and across a Pleistocene glacial–interglacial cycle at Ocean Drilling Program (ODP) Site 999. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2.

scholarly journals Preliminary Estimation and Validation of Polar Motion Excitation from Different Types of the GRACE and GRACE Follow-On Missions Data

2020 ◽  
Vol 12 (21) ◽  
pp. 3490
Author(s):  
Justyna Śliwińska ◽  
Małgorzata Wińska ◽  
Jolanta Nastula
Keyword(s):  
Polar Motion ◽  
Initial Period ◽  
Terminal Phase ◽  
Data Series ◽  
Great Success ◽  
The Earth ◽  
Mass Redistribution ◽  
Different Types ◽  
Grace Mission ◽  
Polar Motion Excitation

The Gravity Recovery and Climate Experiment (GRACE) mission has provided global observations of temporal variations in the gravity field resulting from mass redistribution at the surface and within the Earth for the period 2002–2017. Although GRACE satellites are not able to realistically detect the second zonal parameter (ΔC20) of geopotential associated with the flattening of the Earth, they can accurately determine variations in degree-2 order-1 (ΔC21, ΔS21) coefficients that are proportional to variations in polar motion. Therefore, GRACE measurements are commonly exploited to interpret polar motion changes due to variations in the global mass redistribution, especially in the continental hydrosphere and cryosphere. Such impacts are usually examined by computing the so-called hydrological polar motion excitation (HAM) and cryospheric polar motion excitation (CAM), often analyzed together as HAM/CAM. The great success of the GRACE mission and the scientific robustness of its data contributed to the launch of its successor, GRACE Follow-On (GRACE-FO), which began in May 2018 and continues to the present. This study presents the first estimates of HAM/CAM computed from GRACE-FO data provided by three data centers: Center for Space Research (CSR), Jet Propulsion Laboratory (JPL), and GeoForschungsZentrum (GFZ). In this paper, the data series is computed using different types of GRACE/GRACE-FO data: ΔC21, ΔS21 coefficients of geopotential, gridded terrestrial water storage anomalies, and mascon solutions. We compare and evaluate different methods of HAM/CAM estimation and examine the compatibility between CSR, JPL, and GFZ data. We also validate different HAM/CAM estimations using precise geodetic measurements and geophysical models. Analysis of data from the first 19 months of GRACE-FO shows that the consistency between GRACE-FO-based HAM/CAM and observed hydrological/cryospheric signals in polar motion is similar to the consistency obtained for the initial period of the GRACE mission, worse than the consistency received for the best GRACE period, and higher than the consistency obtained for the terminal phase of the GRACE mission. In general, the current quality of HAM/CAM from GRACE Follow-On meets expectations. In the following months, after full calibration of the instruments, this accuracy is expected to increase.

A NEW APPROACH TO THE DESCRIPTION OF A BABYLONIAN HYDRAULIC WORK BY HERODOTUS

2013 ◽  
Vol 63 (2) ◽  
pp. 888-891 ◽  
Author(s):  
K.L. Katsifarakis ◽  
I. Avgoloupis
Keyword(s):  
Conference Proceedings ◽  
Scientific Knowledge ◽  
Technological Progress ◽  
Wide Spectrum ◽  
Strong Indication ◽  
New Approach ◽  
The Relationship ◽  
Scientific Fields ◽  
Journal Papers

Herodotus is a fascinating author, not only to scholars of history, but also to a wide spectrum of scientists, such as engineers, who are not usually considered to be relevant to humanistic studies. A strong indication of the persisting interest in Herodotus is the recent proliferation of books, for example those of C. Dewald and J. Marincola and A.M. Bowie, on various aspects of his work. At the same time, there is a remarkable interest in the evolution of knowledge in different scientific fields which promotes the understanding of a) the relationship between socio-economic phenomena and technological progress and b) the process of acquiring and documenting scientific knowledge. In the field of hydraulics and hydrology in particular, this interest is documented by journal papers (for example by L.W. Mays et al. and D. Koutsoyiannis et al.), books (for example by A.K. Biswas, Ö. Wikander), book chapters (for example by A.I. Wilson) and conference proceedings.

A New Approach to Color Slow-Motion Video Recording

1968 ◽  
Vol 77 (12) ◽  
pp. 1300-1302 ◽  
Author(s):  
Clarence Boice
Keyword(s):  
Video Recording ◽  
Slow Motion ◽  
New Approach ◽  
Motion Video

CALIFORNIA'S GNOME TRAJECTORY INITIATIVE TO DETERMINE BEST ACHIEVABLE PROTECTION FOR SENSITIVE SHORELINE RESOURCES FROM VESSEL OIL SPILLS

2005 ◽  
Vol 2005 (1) ◽  
pp. 161-165
Author(s):  
Carl Jochums ◽  
Glen Watabyashi ◽  
Heather Parker-Hall
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Oil Pollution ◽  
Time Intervals ◽  
New Approach ◽  
Environmental Consequences ◽  
Playing Field ◽  
Response Planning ◽  
Objective Standard ◽  
Shoreline Protection

ABSTRACT California has initiated a new approach to create an objective standard and regulate best achievable protection (BAP) for sensitive shoreline protection from vessel spills. The Oil Pollution Act (OPA 90) and California's Lempert-Keene-Seastrand Oil Spill Prevention and Response Act (SB 2040) mandate BAP as the standard for preparedness and response. BAP poses the critical response planning questions: “How much response resources should industry provide?” and “In what timeframes should those resources be deployed?” Prior California regulations intended to achieve BAP by relying on vessels to identify hazards, trajectories, environmental consequences, and response resource plans, produced less than optimal results in many instances. Though effective in theory, this approach resulted in fuzzy consequences and vague arrangements for adequate response. Because it was neither clear what sites would be protected (and what response resources would be required) nor at what time, and because it was consequentially not clear what response resources would be engaged to execute protection, drilling C-plans became obtuse. This in turn fostered “paper tiger” OSROs and resulted in an uneven playing field for business competitors. In Californias new approach, OSPR used many of the original concepts to identify BAP by using the NOAA GNOME oil spill model for generic vessel risk threats for California ports and along the California coast. This paper explains the theory, steps, and details. As a result of this process, BAP has been defined in terms of specific site deployments at specific time intervals and presented in tables in regulation. This new approach provides a number of benefits and solutions to the difficult issues in the former approach, including a standard for BAP.

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