A new approach for arriving at higher frequencies through stochastic modelling: application to site attenuation (kappa)

2020 ◽  
Author(s):  
Erion-Vasilis Pikoulis ◽  
Olga-Joan Ktenidou ◽  
Emmanouil Psarakis ◽  
Norman Abrahamson
Keyword(s):  
Fourier Spectrum ◽  
Stochastic Modelling ◽  
Seismic Signal ◽  
New Approach ◽  
Robust Solution ◽  
Seismic Recording ◽  
Exponential Random Variables ◽  
Series Of Experiments ◽  
Modelling Application ◽  
General Estimation

<p>We propose a framework for stochastically modelling the Fourier spectrum of the noisy seismic recording, considering that a seismic signal is a random rather than a deterministic quantity. We show that under this assumption, the noisy recording’s periodogram can be modelled as independent Exponential random variables with a frequency-dependent mean. With this model, estimating seismological parameters can be tackled through Maximum Likelihood (ML), allowing a fast, accurate and robust solution. This new approach constitutes a general estimation framework applicable to any parameter estimation that uses spectral analysis. Here we apply it to the high-frequency decay parameter kappa, which is particularly important for estimating and adjusting ground motion on rock. The improved ML performance is shown through a series of experiments on synthetic and recorded seismograms. The biggest advantage of the new method is its ability to account for the noise in the recording instead of just trying to avoid it, as is typically done when any ‘acceptable’ frequency range is isolated through signal-to-noise (SNR) criteria. As a result, our proposed technique can achieve acceptable results even for what would be typically considered very low and often unusable SNR, pushing the boundary of what is considered usable quality in seismic recordings.</p>

scholarly journals SPATIAL-TEMPORAL ANALYSIS OF SEISMIC WAVE-FIELD FROM THE DISTRIBUTED MINING EXPLOSION

2019 ◽  
Vol 4 (1) ◽  
pp. 141-148
Author(s):  
Sergey Efimov
Keyword(s):  
Wave Field ◽  
Seismic Wave ◽  
Temporal Analysis ◽  
Seismic Signal ◽  
Environmental Risks ◽  
Time Analysis ◽  
Seismic Recording ◽  
Seismic Records ◽  
Seismic Wave Field ◽  
Spatial Temporal Analysis

The article presents a space-time analysis of the seismic wave from a distributed career explosion. The method of direct measurement based on the dynamic model of the wave field is used to form an image of the seismic wave field in the field of quarry explosions. The efficiency of the proposed method is shown by the example of experimental seismic recording processing. The program "Nelumbo" is used to visualize the seismic field, which on the basis of experimental seismic records allows to form an image of the wave field in the space of the hemisphere, the center of which corresponds to the position of the seismometer (registration point). The algorithm of the program "Nelumbo" is based on the Huygens – Fresnel principle and Kirchhoff's theorem. The algorithm of the program allows to allocate from record of a seismic signal frames of a certain duration and to form the image of a wave field in space of a solid angle dimension π. This approach can be used as a tool to analyze the nature of the development of disturbances in the environment and the analysis of environmental risks in the production of blasting.

Determination of optimum tuber planting density for production of tubers in processing ware grades in the potato variety Record

1990 ◽  
Vol 114 (1) ◽  
pp. 11-18 ◽  
Author(s):  
D. C. E. Wurr ◽  
J. R. Fellows ◽  
R. A. Sutherland ◽  
E. J. Allen
Keyword(s):  
Seed Tuber ◽  
Planting Density ◽  
Potato Tubers ◽  
New Approach ◽  
Seed Tubers ◽  
Series Of Experiments ◽  
Number Of Stems ◽  
The Uk ◽  
Seed Tuber Weight

SUMMARYA series of experiments examining the influences of size and spacing of planted potato tubers (‘seed’ tubers) on tuber yields was conducted at four sites in the UK in 1982–84. A new approach to data analysis was used to estimate the optimum tuber planting density for different ware grades. The optimum density, which maximized returns, decreased with increasing seed tuber weight and ratio of seed-tuber cost to ware value and with lower than average total tuber yields. Changing the required ware grade from 40–65 mm to 40–80 mm had a minimal effect on the optimum tuber planting density.Optimum tuber planting densities were lower than in published recommendations but this disparity appeared to be accounted for by differences in the number of stems produced by each planted tuber. There was some evidence that, with lower seed-tuber weights, the optimum planting density differed with site and that at optimum economic densities small and medium seed tubers outyielded large seed tubers.

Recycling red mud from the production of aluminium as a red cement-based mortar

2017 ◽  
Vol 35 (5) ◽  
pp. 500-507 ◽  
Author(s):  
Xiaojie Yang ◽  
Jianfeng Zhao ◽  
Haoxin Li ◽  
Piqi Zhao ◽  
Qin Chen
Keyword(s):  
Red Mud ◽  
Mechanical Performance ◽  
Effective Management ◽  
Current Management ◽  
New Approach ◽  
Air Content ◽  
Negative Effect ◽  
Series Of Experiments ◽  
Hardened Properties ◽  
Performance Variations

Current management for red mud is insufficient and a new method is needed. A series of experiments have been carried out to develop a new approach for effective management of red mud. Mortars without or with 3%, 6% and 9% red mud were prepared and their fresh and hardened properties were measured to access the possibility of recycling the red mud in the production of red cement-based mortar. The mechanisms corresponding to their mechanical performance variations were explored by X-ray powder diffraction and scanning electron microscopy. The results show that the fresh mortars with red mud present an increase of viscosity as compared with the control. However, little difference is found when the content of red mud is altered. It also can be seen that red mud increases flow time and reduces the slump flow of the mortar. Meanwhile, it is found that mortar with red mud is provided with higher air content. Red mud is eligible to adjust the decorative mortar colour. Compressive strength of mortar is improved when less than 6% red mud is added. However, overall it has a slightly negative effect on tensile bond strength. It decreases the Ca(OH)2 content and densifies the microstructure of hardened paste. The heavy metal concentrations in leachates of mortars with red mud are much lower than the values required in the standard, and it will not do harm to people’s health and the environment. These results are important to recycle and effectively manage red mud via the production of red cement-based mortar.

A Market-Based Approach to Pricing With-Profits Guarantees

2000 ◽  
Vol 6 (1) ◽  
pp. 143-213 ◽  
Author(s):  
D.J.P. Hare ◽  
J.A. Dickson ◽  
P.A.P. McDade ◽  
D. Morrison ◽  
R.P. Priestley ◽  
...  
Keyword(s):  
Stochastic Modelling ◽  
New Approach ◽  
Alternative Approach ◽  
Limited Application ◽  
Current Derivative

ABSTRACTThis paper addresses one of the fundamental issues faced by offices in the transacting of with-profits business, namely, the provision of equity-related performance along with maturity guarantees that increase over the lifetime of the policy. The approach commonly followed of using capital to cover the office's investment mismatch risk is considered from an individual policy viewpoint, and, through stochastic modelling, the degree of security represented by different reserve levels identified. An alternative approach using derivatives to provide similar levels of security is then presented and the range of policy proceeds resulting from the two methods compared. While it is recognised that the latter approach may have limited application in practice, the ideas presented could form the basis of a new approach to pricing guarantees under with-profits business that would be consistent with the pricing of current derivative-backed guaranteed products.

scholarly journals Using biochemical agents to intensify the treatment of highly concentrated drilling wastewater

Vestnik MGSU ◽  
2020 ◽  
pp. 1274-1284
Author(s):  
Elena V. Maslennikova ◽  
Vasilii V. Ermakov
Keyword(s):  
Guar Gum ◽  
Standardized Test ◽  
Biological Degradation ◽  
Reliability Of Results ◽  
Multiple Series ◽  
Waste Products ◽  
New Approach ◽  
Accredited Laboratory ◽  
Series Of Experiments ◽  
Impurities Removal

Introduction. The co-authors have developed a new approach to the treatment of highly concentrated drilling wastewater (DWW). The approach is based on the enzymic degradation of polysaccharides that drilling wastewater contains. The research objective is to perform an experimental evaluation of the ability of this biochemical agent to intensify the process of removal of solid impurities from highly concentrated polysaccharide-containing DWW. Materials and methods. The research was performed using standardized test solutions of polysaccharides (carboxymethyl cellulose (CMC), xanthane gum, guar gum), highly concentrated DWW-containing polysaccharides. The reliability of results is ensured by certified methods of analysis, included into the Federal Register of Measurement Procedures and performed by an accredited laboratory, as well as multiple series of experiments. Results. The ability of the biochemical agents (brewing waste (BW) and an enzymatic agent (EP)) to intensify the process of removal of solid impurities from highly concentrated DWW-containing polysaccharides is identified experimentally. The efficiency of biochemical agents used in the process of treatment is determined. The biological degradation of CMC and guar gum solutions is faster than the natural biological degradation that involves BW. Depolymerization time is detected for CMC and guar gum solutions that contain EP. Conclusions. The co-authors have developed a cheaper and more environmentally friendly alternative to existing solutions. It represents a biological method of solid impurities removal from highly concentrated BWW-containing polysaccharides. The use of brewing waste products (BW) as a source of microorganisms, that trigger the polysaccharide hydrolysis, is theoretically substantiated and experimentally proven as a method of treatment of highly concentrated BWW-containing polysaccharides. The expediency of using biochemical agents (BW and EP in isolation) to accelerate the settling rate of solid components of highly concentrated BWW is proven experimentally.

Transforming Prejudice

2020 ◽  
Author(s):  
Melissa R. Michelson ◽  
Brian F. Harrison
Keyword(s):  
Self Esteem ◽  
The Self ◽  
Persuasive Communication ◽  
The Internet ◽  
Transgender People ◽  
New Approach ◽  
Face To Face ◽  
State Of Mind ◽  
Series Of Experiments ◽  
The Subject

Over the last few decades, public opinion has shifted dramatically to be more supportive of gay and lesbian people and their rights, including support for same-sex relationships and marriage. Support for transgender people and rights, in contrast, remains relatively low. As a result, transgender people suffer from discrimination and violence. Shifting attitudes toward transgender people requires a new approach to persuasive communication, one that recognizes the discomfort that many people feel about the subject but also one that appeals to core values and emotions in a way that encourages them to shift their perspective. This book introduces a new theory—Identity Reassurance Theory—which outlines how to transform prejudice against transgender people. The book provides concrete suggestions about how to reduce defensive reactions, helping people take a journey from prejudice to support. Support for Identity Reassurance Theory comes from a series of experiments conducted with individuals face to face, via the Internet, and in the laboratory. When individuals are put in a happier state of mind or when they are reminded about the good in people, they are more supportive of transgender rights. When they are told a story about a mother who did not support transgender people and rights until her own child came out as transgender, they are more likely to support transgender rights. In these and other experiments, Transforming Prejudice describes a method of boosting the self-esteem of recipients of communication to lower their defenses and to encourage them to be more accepting of others who are different than they are.

A three-quarter watt seismic station

1972 ◽  
Vol 62 (4) ◽  
pp. 985-990 ◽  
Author(s):  
K. J. Muirhead ◽  
D. W. Simpson
Keyword(s):  
Dynamic Range ◽  
Seismic Station ◽  
Low Cost ◽  
Seismic Signal ◽  
Total Power ◽  
Time Signal ◽  
Direct Recording ◽  
Total Power Consumption ◽  
Seismic Recording ◽  
Crystal Clock

Abstract A low-power, low-cost instrument using slow speed, direct recording on magnetic tape provides continuous unattended seismic recording in excess of 1 month. The seismic signal is recorded at two gain levels separated by 26 db with a total dynamic range of greater than 70 db. A high-accuracy crystal clock with fully coded digital output and a crystal stabilized radio for reference time-signal reception provide timing to better than 0.1 sec throughout the recording period. Total power consumption is less than 34 watts which enables operation for 1 month on dry cell batteries. The weight of the complete system including seismometer and batteries is less than 100 lb. Ten instruments have been used to record seismic signals ranging from localized microearthquake activity to explosions and teleseismic events.

Analysis of Hyper-Redundant Manipulators

1999 ◽  
Author(s):  
Farshid Maghami Asl ◽  
Hashem Ashrafiuon ◽  
C. Nataraj
Keyword(s):  
Inverse Kinematic ◽  
Redundant Manipulators ◽  
Full Extension ◽  
Inverse Dynamic ◽  
Inverse Kinematic Problem ◽  
New Approach ◽  
Robust Solution ◽  
Numerical Examples ◽  
Planar Manipulators ◽  
Joint Velocity

Abstract A new approach to solve the inverse kinematic problem for hyper-redundant planar manipulators following any desired path is presented. The method is singularity free and provides a robust solution even in the event of mechanical failure of some of the robot actuators. The approach is based on defining virtual layers and dividing them into virtual/real three-link or four-link sub-robots. It starts by solving the inverse kinematic problem for the sub-robot located in the lowest virtual layer, which is then used to solve the inverse kinematic equations for the sub-robots located in the upper virtual layers. An algorithm is developed which provides a singularity-free solution up to full extension through a configuration index. The configuration index can be interpreted as the average of the determinants of the Jacobians of the sub-robots. The equations for the velocities and accelerations of the manipulator are solved by extending the same approach where it is realized that the value of configuration index is critical in maintaining joint velocity continuity. The inverse dynamic problem of the robot is also solved to obtain the torques required for the robot actuators to accomplish its task. Computer simulations of several hyper-redundant manipulators using the proposed method are presented as numerical examples.

Stochastic modelling of fault gouge zones: implications for fault seal analysis

2019 ◽  
Vol 496 (1) ◽  
pp. 163-197 ◽  
Author(s):  
Neil T. Grant
Keyword(s):  
Stochastic Modelling ◽  
Fault Gouge ◽  
Well Log ◽  
Practical Application ◽  
Fault Rock ◽  
Fault Rocks ◽  
New Approach ◽  
Slip Surfaces ◽  
Modelling Approach

AbstractFault zones are complex, and show considerable variability in both structure and the distribution of associated fault rocks within the fault core: the zone that localizes most strain and displacement. It is the fault-core gouge zone and associated slip surfaces which provide the cross-fault seal when permeable layers are juxtaposed. Predicting the sealing properties of fault gouge zones is difficult but often required when evaluating faults in exploration prospects. A stochastic modelling approach is described to help better understand the compositional controls on fault gouge seal potential. The model is populated with a random assemblage of four fault rock components: shale smears, shaly gouge, cataclastic gouge and low-strain host-rock lenses. Harmonic averaging of permeability and arithmetic averaging of Vshale are then used to upscale the properties, and to propose a simple permeability–Vshale model for fault rocks. Practical application of the model is discussed by developing an empirical link between standard well-log data and associated fault rock effective permeability. This new approach has the potential to offer a simple well-log-based fault seal model. The utility of the model is demonstrated with a case study, comparing the results to those generated using other published techniques.

Geophone ground coupling

Geophysics ◽  
1984 ◽  
Vol 49 (6) ◽  
pp. 722-731 ◽  
Author(s):  
Christine E. Krohn
Keyword(s):  
Resonant Frequency ◽  
Low Frequency ◽  
Seismic Signal ◽  
Soil Conditions ◽  
Damping Factor ◽  
Base Diameter ◽  
Single Coupling ◽  
Seismic Recording ◽  
Frequency Coupling ◽  
Wave Recording

The geophone ground coupling for vertical and horizontal geophones has been measured in the laboratory and in the field. The data can be fit to a calculated geophone response with a single coupling resonant frequency and damping factor. For frequencies much lower than the coupling resonant frequency, the geophone accurately follows the ground motion, but for higher frequencies the coupling can alter both the amplitude and phase of the seismic signal. The normal planting of vertical geophones in the field results in coupling adequate for conventional recording that uses frequencies less than 100 Hz. However, for very loose soils or for high‐frequency seismic recording, I recommend that the geophones be buried to place the geophones in firmer soil. The coupling resonant frequency for vertical geophones is determined by the firmness of the soil, and I have measured resonant frequencies ranging from 100 to 500 Hz at different locations. The coupling resonant frequency is insensitive to changes in the mass or base diameter of the vertical geophones. Because the firmness of the soil increases with depth, the coupling resonant frequency can he increased by burial of the geophones or by the use of longer spikes. Adequate coupling is very important in shear‐wave recording because the rocking of horizontal geophones causes a low‐frequency coupling resonance. It is crucial that horizontal geophones be planted with their bases firmly contacting the soil. Geophones so planted have a resonance around 130 Hz, whereas those 1 cm off the ground can have a resonance of 30 Hz or lower. Soil conditions have little effect on the resonant frequency. Horizontal geophones with 1-inch spikes are as well coupled as those with longer spikes, but the best coupling is achieved by burial of the geophones.

Sign in / Sign up

Export Citation Format

Share Document