Characterization of Nutrients in Built-up Broiler Litter Using Trench and Random Walk Sampling Methods

The present research was carried out at the DER/FCAV, São Paulo State University - Brazil, with the purpose of analyzing the quantity and quality of biogas produced by six types of substrates. The substrates used in the anaerobic digestion were characterized as: 1- Litter of broiler (LB); 2- Grinded broiler litter (GBL); 3- Broiler litter with wood shavings (BLWS); 4- Grinded broiler litter with wood shavings (GBLWS); 5- Broiler litter with peanut hulls (BLPH); 6- Grinded broiler litter with peanut hull (GBLPH). It was concluded from the collected data that: the (GBL) substrate showed a superior biogas accumulated production in relation to the other substrates, while the BLWS presented an inferior accumulated production; the grinded substrates showed higher quantities of accumulated biogas in relation to the non-grinded substrates, except for GBLPH, with 20.9 m³ inferior than BLPH; the period of maximum biogas production started from 45 to 60 days, declining after 120 days; at 57 days after filling up the digesters the biogas produced had levels of CH4 superior than 53%, and from 99 days all of them produced biogas with levels of CH4 superior than 70%; LB and GBL presented higher concentrations of CH4 in the biogas.

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Mid-Flock and Post-Harvest Spatial Characterization of Broiler Litter Gas Flux and Nutrients

International Journal of Poultry Science ◽

10.3923/ijps.2016.175.181 ◽

2016 ◽

Vol 15 (5) ◽

pp. 175-181 ◽

Cited By ~ 1

Author(s):

Dana M. Miles ◽

John P. Brooks ◽

Philip A. Moore Jr.

Keyword(s):

Gas Flux ◽

Broiler Litter ◽

Post Harvest ◽

Spatial Characterization

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Characterization of the Structure and Transport Properties of Alginate/Chitosan Microparticle Membranes Utilized in the Pervaporative Dehydration of Ethanol

Polymers ◽

10.3390/polym12020411 ◽

2020 ◽

Vol 12 (2) ◽

pp. 411

Author(s):

Gabriela Dudek ◽

Przemysław Borys ◽

Anna Strzelewicz ◽

Monika Krasowska

Keyword(s):

Random Walk ◽

Transport Properties ◽

Experimental Studies ◽

Transport Parameters ◽

Void Space ◽

Fractal Parameters ◽

Dehydration Processes ◽

Average Size ◽

High Resolution Microscopy

The structure and transport properties of alginate/chitosan microparticle membranes used in ethanol dehydration processes were investigated. The membranes were characterized based on images obtained from high-resolution microscopy. The following parameters were determined: the observed total amount of void space, the average size of the void domains, their length and diameter, the fractal dimension, and the generalized stochastic fractal parameters. The total amount of void space was determined to be between 54% and 64%. The average size of the void domains is smaller for alginate membranes containing neat (CS) and phosphorylated (CS-P) chitosan particles when compared to those membranes filled with glycidol-modified (CS-G) and glutaraldehyde crosslinked (CS-GA) chitosan particles. Furthermore, the transport of ethanol and water particles through the studied membranes was modelled using a random walk framework. It was observed that the results from the theoretical and experimental studies are directly correlated. The smallest values of water to ethanol diffusion coefficient ratios (i.e., 14) were obtained for Alg (sodium alginate) membranes loaded with the CS and CS-P particles, respectively. Significantly larger values (27 and 19) were noted for membranes filled with CS-G and CS-GA particles, respectively. The simulation results show that the size of channels which develop in the alginate matrix is less suited for ethanol molecules compared to water molecules because of their larger size. Such a situation facilitates the separation of water from ethanol. The comparison of the structural analysis of the membranes and random walk simulations allows one to understand the factors that influence the transport phenomena, in the studied membranes, and comment on the effect of the length, diameter, number of channels, and variations in the pore diameters on these transport parameters.

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Combining Losing Games into a Winning Game

Fluctuation and Noise Letters ◽

10.1142/s0219477519500032 ◽

2019 ◽

Vol 18 (01) ◽

pp. 1950003 ◽

Cited By ~ 3

Author(s):

Bruno Rémillard ◽

Jean Vaillancourt

Keyword(s):

Asymptotic Behavior ◽

Random Walk ◽

Random Walks ◽

Random Environment ◽

Regime Switching ◽

Random Environments ◽

Full Characterization ◽

Parrondo’S Paradox ◽

Random Subspaces

Parrondo’s paradox is extended to regime switching random walks in random environments. The paradoxical behavior of the resulting random walk is explained by the effect of the random environment. Full characterization of the asymptotic behavior is achieved in terms of the dimensions of some random subspaces occurring in Oseledec’s theorem. The regime switching mechanism gives our models a richer and more complex asymptotic behavior than the simple random walks in random environments appearing in the literature, in terms of transience and recurrence.

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Amenability of groupoids and asymptotic invariance of convolution powers

Topology, Geometry, and Dynamics - Contemporary Mathematics ◽

10.1090/conm/772/15482 ◽

2021 ◽

pp. 69-92

Author(s):

Theo Bühler ◽

Vadim Kaimanovich

Keyword(s):

Random Walk ◽

Locally Compact Group ◽

Probability Measures ◽

Locally Compact ◽

Von Neumann ◽

Original Definition ◽

Convolution Powers ◽

Measure Class ◽

Definition Of

The original definition of amenability given by von Neumann in the highly non-constructive terms of means was later recast by Day using approximately invariant probability measures. Moreover, as it was conjectured by Furstenberg and proved by Kaimanovich–Vershik and Rosenblatt, the amenability of a locally compact group is actually equivalent to the existence of a single probability measure on the group with the property that the sequence of its convolution powers is asymptotically invariant. In the present article we extend this characterization of amenability to measured groupoids. It implies, in particular, that the amenability of a measure class preserving group action is equivalent to the existence of a random environment on the group parameterized by the action space, and such that the tail of the random walk in almost every environment is trivial.

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Quantitative Characterization of 2-D Porous Channels by Using Fractal Random Walk Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.614-615.234 ◽

2012 ◽

Vol 614-615 ◽

pp. 234-238

Author(s):

Xiao Chuan Li ◽

Xiang Yong Huang ◽

Xiao Feng Cui

Keyword(s):

Thermal Conductivity ◽

Random Walk ◽

Effective Thermal Conductivity ◽

Fractal Dimensions ◽

Critical Factor ◽

Sierpinski Carpet ◽

Porous Channels ◽

Volume Method ◽

Sierpiński Carpet

An improved random walk mode is proposed based on fractal geometry and random walk theory to characterize the features of porous channels quantitatively. Three different types of fractal Sierpinski carpet structures are obtained by iterative method. The effective thermal conductivities and fractal dimensions are calculated by finite volume method and statistical fractal algorithm respectively. The influences of porosity and pore distribution on effective thermal conductivity are investigated. Results indicate that, the effective thermal conductivity may be different for various structures with the same porosity, and the direction of porous channels formed by connected pores is the critical factor. The spectral fractal dimension of porous channels dD in the direction of temperature gradient coincides with the effective thermal conductivity of Sierpinski carpet.

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Characterization of Inter-System Biases in GPS + BDS Precise Point Positioning

Applied Sciences ◽

10.3390/app10144968 ◽

2020 ◽

Vol 10 (14) ◽

pp. 4968

Author(s):

Cheng Ke ◽

Yanning Zheng ◽

Shengli Wang

Keyword(s):

Random Walk ◽

Precise Point Positioning ◽

Satellite System ◽

Random Walk Process ◽

Ambient Environment ◽

Antenna Type ◽

Point Positioning ◽

Short Baselines ◽

The One

With the combination of multi-GNSS data, the precise-point positioning (PPP) technique can improve its accuracy, availability and reliability: Inter-system bias (ISB) is the non-negligible parameter in multi-GNSS PPP. To further enhance the performance of multi-GNSS PPP, it is crucial to analyze the characterization of inter system biases (ISBs) and model them properly. In this contribution, we comprehensively investigate the characterization of ISBs between global positioning system (GPS) and BeiDou navigation satellite system (BDS) in different situations. (1) We estimate ISB by using different precise products from the Center for Orbit Determination (CODE), Deutsches GeoForschungsZentrum (GFZ) and Wuhan University (WHU). The results indicate that the one-day estimates of ISB are stable when using CODE and WHU products, whereas the estimates based on GFZ products vary remarkably. As for the three-day time series of ISB, a sudden jump exists between two adjacent days, which is due to the change of satellite clock datum; (2) We investigate the ISB characterization affected by the ambient environments of the receivers. The result shows that the ISBs estimated from receivers (and antennas) with same type are still inconsistent, which indicates that the ambient environment, probably the temperature, influences the ISB characterization as well, since the receivers are in different areas; (3) We analyze the ISB characterization affected by receiver and antenna type with the same ambient environment. To ensure the same ambient environment, the ultra-short baselines were applied to investigate the ISB characterization affected by the receiver and antenna type. With the insights into ISB characterizations, we carry out combined GPS and BDS PPP with modeling the ISB as time constant, random walk process and white noise. The results suggest that the random walk process outperforms in most cases, since it strengthens the model to some extend and, at the same time, considers the variation of ISBs.

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