scholarly journals On the Determination of Coordination Numbers of Coupled DEM-DFN Model for Modeling Fractured Rocks

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaoyi Xu ◽  
Li-Yun Fu ◽  
Ning Liu ◽  
Tongcheng Han
Keyword(s):  
Coordination Number ◽  
Fractured Rocks ◽  
Granular Media ◽  
Simple Formulation ◽  
Coordination Numbers ◽  
System A ◽  
Window Selection ◽  
Set Up ◽  
Dfn Model

Natural fractured rocks usually contain background granular media and multi-scale fractures. The coordination number is a crucial factor to characterize the connection of microstructural elements. The determination of coordination numbers for modeling fractured rocks is essential to interpret the distribution of cracks related to micromechanical properties. We have built a consistent workflow of discrete element models (DEMs) coupled with discrete fracture networks (DFNs). This DEM-DFN model could provide a simple formulation for high calculation efficiency to model a more realistic and detailed description of fracture system. A series of numerical experiments are set up, aiming to correlate window radius, particle size, and crack length, which will benefit the window selection for measuring coordination numbers based on the crack characteristics. The coordination number determined in the DEM-DFN modeling can be used to identify crack patterns in the spatial distribution.

Wechselwirkungen in Molekülkristallen, 156 [1, 2]. Kristallzüchtung und Strukturbestimmung von (Imidodiphosphat)-Alkalisalzen mit Kationen niedriger und hoher Koordinationszahlen / Interaction in Molecular Crystals, 156 [1, 2]. Crystal Growth and Structure Determination of Alkali(imidodiphosphate) Salts with Cations of Low and High Coordination Numbers

2000 ◽  
Vol 55 (9) ◽  
pp. 773-784 ◽  
Author(s):  
Hans Bock ◽  
Erik Heigel ◽  
Norbert Nagel
Keyword(s):  
Crystal Growth ◽  
Coordination Number ◽  
Molecular Crystals ◽  
Chelating Ligands ◽  
Chain Polymer ◽  
Coordination Numbers ◽  
Structural Differences ◽  
A Chain ◽  
High Coordination

Imidodiphosphates ⊖N[PO(OR)2]2 and Imidodiphosphonates ⊖N[POR2]2 are effective chelating ligands for a variety of metal cations including even Na⊕, for which a lipophilically wrapped hexameric polyion cluster has been structurally characterized. The corresponding hexameric lithium and polyrubidium ion complexes reported here exhibit considerable structural differences: The rather small Li⊕ cations of coordination number five and tetraphenylimidodiphosphate form an isolated hexameric aggregate analogous to the Na⊕ one, whereas the larger Rb⊕ with coordination number seven and (3,4-dimethylphenyl)substituents crystallizes as a chain polymer. Based on the crystal structures, the dominant Coulomb attractions between cations and anions, the spatial requirement of the ligands and the essential phenyl/phenyl interactions in their lipophilic skin are discussed

Rapid Determination of Formaldehyde in Dried Bean Milk Cream by HPLC with Pre-Column Derivatization

2012 ◽  
Vol 554-556 ◽  
pp. 1493-1497
Author(s):  
Qi Tong ◽  
Jian Zheng Song ◽  
Qiu Rong Li
Keyword(s):  
High Performance ◽  
Rapid Determination ◽  
Rapid Test ◽  
Chromatography Method ◽  
System A ◽  
Controlling System ◽  
Relative Standard ◽  
Liquid Chromatography Method ◽  
Set Up

A high-performance liquid chromatography method was set up for rapid determination of formaldehyde in dried bean milk cream. This thesis studies the Nash derivatization, derivative solubility, reaction time, amounts of Nash and derivative stability. The derivative is chromatographic separated by Agilent Zorbax Eclipse XDB-C18 column (4.6mm× 250mm, 5μm) and detected by index detector with VWD (412nm). The heater does not need the temperature-controlling system. A mobile phase was composed of acetonitrile and water (50:50, V/V) at a flow rate of 0.8 mL/min. Under the conditions of the above-mentioned test, the developed calibration curves displayed good linearity over a concentration range of 0.00 to 0.80mg/L, with a correlation coefficient exceeding 0.9998. Average spike recovery was found in a range of 88% to 91%, with a relative standard deviation (RSD) between 1.1% and 4.0%.The minimum detection limit of source is 0.013mg/Kg. The method can be used for rapid test on formaldehyde preservative in dried bean milk cream.

Towards a Five-Axis Machining CAPP System: A Set-Up Planning Tool Solving Accessibility Constraints

2009 ◽  
Vol 9 (4) ◽  
Author(s):  
V. Capponi ◽  
F. Villeneuve
Keyword(s):  
Machine Tools ◽  
Planning System ◽  
Computer Assisted ◽  
Planning Tool ◽  
Structural Part ◽  
System A ◽  
Process Planning System ◽  
Set Up ◽  
Five Axis

The overall aim of the authors’ work is to create a computer aid to support the macroplanning of five-axis parts, and in this context this paper presents the methodology developed to enable the determination of set-up orientations on five-axis machine-tools. The process starts with an access model that encompasses all the machining directions encountered in five-axis operations. Then an enhanced visibility-based modeling and algorithm are proposed in order to solve accessibility constraints while planning the setups for double-sided parts. The proposed algorithm is illustrated on an industrial aircraft structural part. To conclude, options to integrate the proposed method in a computer assisted process planning system are discussed.

scholarly journals PRACTICAL DETERMINATION OF THE COORDINATION NUMBER IN GRANULAR MEDIA

2011 ◽  
Vol 25 (1) ◽  
pp. 55 ◽  
Author(s):  
Patricia Jouannot-Chesney ◽  
Jean-Paul Jernot ◽  
Christian Lantuéjoul
Keyword(s):  
Coordination Number ◽  
Measurement Method ◽  
Granular Media ◽  
Global Analysis ◽  
Initial Structure ◽  
Single Measurement ◽  
Practical Applications ◽  
The Mean ◽  
Number Of Particles

In a random stacking of particles, the coordination number is defined as the mean number of particles touching a given one. A classical measurement by image analysis is directly based on this definition. It can be applied in the theoretical case of a global analysis but some problems occur for practical applications. We propose here a new measurement method based on the contribution to the Euler-Poincaré characteristic. A single measurement is performed both on the initial structure (particles linked by contacts) and on the segmented structure (isolated particles). The proposed method is robust w.r.t. the shape of the particles and their contacts.

scholarly journals Russian Revolution and the International Legal System

Monitor ISH ◽  
2018 ◽  
Vol 20 (1) ◽  
pp. 69-80
Author(s):  
Andraž Zidar
Keyword(s):  
Soviet Union ◽  
Legal System ◽  
Dominant Role ◽  
Russian Revolution ◽  
Cultural Rights ◽  
System A ◽  
The Soviet Union ◽  
International Legal System ◽  
Set Up

Two potent ideologies came to loggerheads after WWI: communism, which rose to the fore after the Russian revolution, and the so far dominant liberalism. At first glance the two ideologies share surprisingly similar views on the fundamental questions of the international legal system. But a more thorough look at the development of the Soviet doctrine of international law reveals some fundamental differences. The goal of the Russian revolution was to set up a worldwide socialist society, with the working class given a dominant role. This goal dissolved after the break-up of the Soviet Union. Nonetheless, it is possible to identify in the international legal system a positive and still valid legacy of the Russian revolution, such as the principle of the self-determination of nations, the concept of economic, social and cultural rights, the principle of public conclusion of treaties, the prohibition of aggressive war, as well as a polycentric view of the world structure.

Respirometry for determination of the influents SS-concentration

1996 ◽  
Vol 33 (1) ◽  
pp. 311-323 ◽  
Author(s):  
A. Witteborg ◽  
A. van der Last ◽  
R. Hamming ◽  
I. Hemmers
Keyword(s):  
Experimental Design ◽  
Activated Sludge ◽  
Substrate Concentration ◽  
Full Scale ◽  
Activated Sludge Process ◽  
Respiration Rates ◽  
On Line ◽  
Large Measurement ◽  
Set Up

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.

Determination of trace concentrations of copper by FIA-FAAS after preconcentration on chelating sorbents

1989 ◽  
Vol 54 (7) ◽  
pp. 1785-1794 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Josef Komárek ◽  
Zbyněk Zdráhal
Keyword(s):  
Sampling Frequency ◽  
Copper Determination ◽  
Flow Rates ◽  
Sample Injection ◽  
Injection Flow ◽  
Chelating Sorbents ◽  
Set Up ◽  
Trace Concentrations ◽  
Better Than

A FIA-FAAS apparatus containing a six-channel sorption equipment with five 3 x 26 mm microcolumns packed with Spheron Oxin 1 000, Ostsorb Oxin and Ostsorb DTTA was set up. Combined with sorption from 0.002M acetate buffer at pH 4.2 and desorption with 2M-HCl, copper can be determined at concentrations up to 100, 150 and 200 μg l-1, respectively. For sample and eluent flow rates of 5.0 and 4.0 ml min-1, respectively, and a sample injection time of 5 min, the limit of copper determination is LQ = 0.3 μg l-1, repeatability sr is better than 2% and recovery is R = 100 ± 2%. The enrichment factor is on the order of 102 and is a linear function of time (volume) of sample injection up to 5 min and of the sample injection flow rate up to 11 ml min-1 for Spheron Oxin 1 000 and Ostsorb DTTA. For times of sorption of 60 and 300 s, the sampling frequency is 70 and 35 samples/h, respectively. The parameters of the FIA-FAAS determination (acetylene-air flame) are comparable to or better than those achieved by ETA AAS. The method was applied to the determination of traces of copper in high-purity water.

Extra-Column Effects in Determination of Rate Parameters by the Chromatographic Method

1996 ◽  
Vol 61 (6) ◽  
pp. 844-855 ◽  
Author(s):  
Olga Šolcová ◽  
Petr Schneider
Keyword(s):  
Chromatographic Method ◽  
Dynamic Method ◽  
Axial Dispersion ◽  
Transport Parameters ◽  
Porous Particles ◽  
Loop Detector ◽  
Single Pellet ◽  
Set Up ◽  
Extra Column Effects

It was shown that the sampling loop, detector and connecting elements in the chromatographic set-up for determination of transport parameters by the dynamic method significantly influence the response peaks from columns packed with porous or nonporous particles. A method, based on the use of convolution theorem, was developed which can take these effects into account. The applicability of this method was demonstrated on the case of axial dispersion in a single-pellet-string column (SPSR) packed with nonporous particles. It is possible to handle also responses from columns packed with porous particles by a similar procedure.

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