New Method for Sampling Groundwater Colloids under Natural Gradient Flow Conditions

1996 ◽  
Vol 30 (10) ◽  
pp. 3094-3101 ◽  
Author(s):  
Noam Weisbrod ◽  
Daniel Ronen ◽  
Ronit Nativ
Keyword(s):  
Gradient Flow ◽  
New Method ◽  
Natural Gradient ◽  
Flow Conditions

Characterization of suspended particles collected in groundwater under natural gradient flow conditions

1992 ◽  
Vol 28 (5) ◽  
pp. 1279-1291 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
U. Weber ◽  
A. J. Amiel ◽  
E. Klein
Keyword(s):  
Gradient Flow ◽  
Suspended Particles ◽  
Natural Gradient ◽  
Flow Conditions

Characterisation of Suspended Particles and Associated Metals in Groundwater under Natural Gradient Flow Conditions*

1993 ◽  
Vol 27 (7-8) ◽  
pp. 179-186 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
A. J. Amiel
Keyword(s):  
Organic Matter ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Gradient Flow ◽  
Suspended Particles ◽  
Average Concentration ◽  
Saturated Zone ◽  
Natural Gradient ◽  
Flow Conditions ◽  
Anoxic Conditions

Microscale Eulerian variations in the flux, mineralogical composition and size of suspended particles have been found in a contaminated sandy aquifer under natural gradient flow conditions () during an 8 month study period. Particle variability has been detected along a 16 m saturated section of the aquifer at a scale of centimeters and meters in the vertical and horizontal dimensions, respectively. The average concentration of particles in groundwater varied between 1 to 70 mg/l. The particles were primarily composed of CaCO3 (11% to 57%), quartz (7% to 39%) and clays (8% to 43%). Most of the particles were within the 140 to 3,000 nm size range with size modes varying from 310 to 660 nm. The large amounts of suspended particles are considered to be related to high inputs of dissolved organic carbon into groundwater from sewage effluents which have been used for agricultural irrigation since the early 1960's. As a result of organic matter biodegradation in the saturated zone, anoxic conditions developed and the pCO2 content of groundwater increased dramatically. It is postulated that part of the carbonate cement of the rocks dissolved and detrital CaCO3, quartz and clay were released as colloidal particles. In the prevailing anoxic conditions of groundwater at the study site (DO < 1 mg/l) colloidal stability is enhanced by organic matter coating of particles. The transport of metals associated with suspended particles in the saturated zone and the interaction of these particles in the aquifer environment have been ascertained through a comparison of the distribution coefficient of 17 elements as a function of depth. *Contribution No. 61, Department of Environmental Sciences and Energy Research, The Weizmann Institute of Science.

Conversion of Centrifugal Compress Performance Curves Considering Non-Similar Flow Conditions

1982 ◽  
Author(s):  
W. Fister ◽  
J. Kotzur
Keyword(s):  
Energy Transfer ◽  
Centrifugal Compressor ◽  
Performance Testing ◽  
Reynolds Numbers ◽  
New Method ◽  
Flow Conditions ◽  
Flow Losses ◽  
Performance Curves ◽  
Thermodynamic Performance ◽  
Mach And Reynolds Numbers

Thermodynamic performance testing of centrifugal compressor cannot always be implemented at the same conditions on which the rating of the machine was based. To permit them to be compared to the rated values, the test values must therefore be converted to the respective suction data, gas properties and speeds. Conversion methods applied today which assume similar or approximately similar flow conditions for testing and rating, specify in various instance too narrow limits for this. A new conversion method based on few measurement values was developed to consider the influence exerted by the most important parameters, such as Mach and Reynolds numbers, etc. on energy transfer in the stage and on flow losses. Performance curves converted according to the new method, are compared to actually measured values.

A Novel Blind Source Separation Method Based on the Extended Natural Gradient

2012 ◽  
Vol 433-440 ◽  
pp. 3570-3576
Author(s):  
Yu Feng Xue ◽  
Yu Jia Wang ◽  
Qiu Dong Sun
Keyword(s):  
Iterative Algorithm ◽  
Blind Source Separation ◽  
Lie Group ◽  
Mathematical Proof ◽  
Source Separation ◽  
Separation Method ◽  
New Method ◽  
Invariance Property ◽  
Natural Gradient ◽  
Group Invariance

In this paper, a new method is introduced to derive the extended natural gradient, which was proposed by Lewicki and Sejnowski in [1]. However, they made their derivation under many approximations, and the proof is also very complicated. To give a more rigors mathematical proof for this gradient, the Lie group invariance property is introduced which makes the proof much easier and straightforward. In addition, an iterative algorithm through Newton's method is also given to estimate the sources efficiently. The results of the experiments confirm the efficiency of the proposed method.

A New Method to Investigate the Failure Envelopes of Offshore Foundations

2016 ◽  
Author(s):  
Yinghui Tian ◽  
Tianyuan Zheng ◽  
Tao Zhou ◽  
Mark J. Cassidy
Keyword(s):  
Test Method ◽  
New Method ◽  
Combined Loading ◽  
Resistance Force ◽  
Flow Conditions ◽  
Load Path ◽  
Failure Envelope ◽  
Load Paths ◽  
Failure Envelopes ◽  
Probe Test

This paper presents an alternative numerical method in addition to the traditional ‘probe test’ to investigate the combined loading failure envelopes of foundations in soil. In the ‘probe test’ method, the foundation is displaced with a specified displacement path and eventually the soil resistance force reaches a stabilised point sitting on the failure envelope in the load space. While the displacement paths are arbitrarily or empirically set, the positions of the stabilised loads on the failure envelope can not be predetermined or planned. This paper’s new method, however, can specify the load paths, which directly shoot onto the failure envelope. This allows the investigation of the failure envelope can be better achieved with planned load paths. In addition, this new method is advantageous in checking the plastic flow conditions (i.e. normality of the failure envelope) as the load path directions are predetermined.

scholarly journals Natural Gradient Flow in the Mixture Geometry of a Discrete Exponential Family

Entropy ◽  
2015 ◽  
Vol 17 (6) ◽  
pp. 4215-4254 ◽  
Author(s):  
Luigi Malagò ◽  
Giovanni Pistone
Keyword(s):  
Exponential Family ◽  
Gradient Flow ◽  
Natural Gradient
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