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  • Open Access

    ARTICLE

    Numerical Simulation of Debris Flow Runout Using Ramms: A Case Study of Luzhuang Gully in China

    Jianjun Gan1,2, Y. X. Zhang2,*

    CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.3, pp. 981-1009, 2019, DOI:10.32604/cmes.2019.07337

    Abstract This study proposes a comprehensive method, which consists of field investigation, flume test and numerical simulation, to predict the velocity and sediment thickness of debris flow. The velocity and sediment thickness of the debris flow in mountainous areas can provide critical data to evaluate the geohazard, which will in turn help to understand the debris runout. The flume test of this debris prototype can provide friction coefficient and viscosity coefficient which are important for numerical simulation of debris flow. The relation between the key parameters in the numerical modelling using the Voellmy model and debris-flow rheology is discussed. Through simulation… More >

  • Open Access

    ARTICLE

    The nutrient accumulation pattern and cycling in natural secondary forests in North China. A case study from the Caijiachuan watershed, Shanxi Province

    Wei TX1, XJ Zhang1,2, JZ Zhu1

    Phyton-International Journal of Experimental Botany, Vol.83, pp. 213-223, 2014, DOI:10.32604/phyton.2014.83.213

    Abstract In order to examine the nutrient content, and the distribution and accumulation patterns of individual nutrients in the natural secondary forests (NSFs), sample NSF plots were selected in the Caijiachuan watershed on the Loess Plateau. On the basis of a comprehensive field inventory to the NSFs in Caijiachuan watershed, a 40 m × 40 m sample plot was selected as the representative plot. Each tree plant was then measured to select the standard tree in accordance with a diameter-scale. For measurement of the biomass in the above-ground part of the tree, it was divided into parts and measured. The study… More >

  • Open Access

    ARTICLE

    Responses of Conocarpus lancifolius to environmental stress: a case study in the semi-arid land of Kuwait

    Redha A, P Suleman, R Al-Hasan, M Afzal

    Phyton-International Journal of Experimental Botany, Vol.81, pp. 181-190, 2012, DOI:10.32604/phyton.2012.81.181

    Abstract Cococarpus lancifolius Engl. grows wild in Djibouti, Somalia and East Africa, and South Asia. The species was introduced into Kuwait, where it is exposed to several stresses: oil pollution, salinity, high temperature and harsh climatic conditions. These conditions are prevalent in its semi-arid environment. In this study, the impact of salinity (2, 6 and 10%), temperature (20, 30 and 40 °C), polyethylene glycol (10, 30 and 60%) and drought has been investigated on C. lancifolius. Proline (Pro) accumulation (5.5 ± 0.03 µg/g dry weight; p≤0.05-0.005), protein (16.47 ± 0.052 mg/g; p≤0.001), free amino acids (10.92 ± 0.082 mg/g; p≤0.006) and… More >

  • Open Access

    ARTICLE

    Changes in soil phosphorus fractions caused by cropping without nutrient reposition. A case study

    Barresi O1,2, VM Chiocchio1,2, RS Lavado2

    Phyton-International Journal of Experimental Botany, Vol.87, pp. 14-17, 2018, DOI:10.32604/phyton.2018.87.014

    Abstract Previous studies in soils of the Pampas region indicate the prevalence of calcium phosphates within the very complex mix of phosphorus (P) compounds in the soils. We studied the changes in P fractions in a punctual situation in the Pampas region. The sampling was carried out in a farm located near the city of Junín (-34.585; -60.9589) and the soil was Junín series Typic Hapludoll. The farm was devoted to grazing and sporadic crops, but from the last 30 years changed to continuous agriculture. At no time fertilization matched nutrients removal by crops. The soil P fractions were determined using… More >

  • Open Access

    ARTICLE

    Trace Elements in the Soil-Plant Systems of Copper Mine Areas-A Case Study From Murgul Copper Mine From the Black Sea Region of Turkey

    Munir Ozturk1,*, Volkan Altay2, Mahir Kucuk3, Ibrahim Ertuğrul Yalçın4

    Phyton-International Journal of Experimental Botany, Vol.88, No.3, pp. 223-238, 2019, DOI:10.32604/phyton.2019.07446

    Abstract This study presents a case study on the heavy metal analysis of soil and plant samples around the Murgul copper mine, one of the first and most important mining areas in Turkey. An attempt has been made to investigate the status of trace elements like Al3+, Fe2+, Cu2+, Zn2+, Pb2+, Ni2+, Co2+ and Cd2+ in soils and plants. The sampling localities were taken from 500 m, 600 m, and 1000 m altitudes around the factory and at 1400 m in the forest zone. The aboveground parts and foliage ash of Silene compacta, Tussilago farfara, Smilax excelsa, Rhododendron ponticum, R. luteum,… More >

  • Open Access

    ABSTRACT

    A Case Study of Mud-Weight Design with Finite Element Method for Subsalt Wells

    X.P. Shen, A. Diaz, T. Sheehy ,

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.3, pp. 73-74, 2011, DOI:10.3970/icces.2011.016.073

    Abstract This paper presents a case study for the design of a mud-weight window (MWW) with three-dimensional (3D) finite-element (FE) tools for subsalt wells. The trajectory of the target well penetrates a 20,000-ft thick salt body.

    The numerical solution of the MWW for the target wellbore consists two parts: the shear failure gradient (SFG) and the fracture gradient (FG). Because the pore pressure and material distributions are nonuniform, the calculations of SFG and FG must be performed with submodeling techniques for a given depth point at a smaller local scale. A numerical scheme has been proposed for calculating the SFG… More >

  • Open Access

    ABSTRACT

    CFD case study to optimize surgical adjustment of ventricular assist device implantation to minimize stroke risk part II: transient vascular resistance model

    Eduardo Divo1, Alain Kassab2, Greisa Mendez3, I. RicardoArgueta-Morales4, William M. DeCampli4,5

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.4, pp. 125-128, 2010, DOI:10.3970/icces.2010.015.125

    Abstract In order to properly account for the unsteady nature of the flow field generated by the cardiac ejection in an Aortic Arch with an implanted Left Ventricular Assist Device (LVAD) Computational Fluid Dynamics (CFD) model, a closed-loop external vascular model is necessary. Such external model is coupled to the CFD model to dictate the flow field boundary conditions at the outlets of the CFD model and thus, control the flow splits through the different branches that stem out of the aortic arch throughout the cardiac cycle. More >

  • Open Access

    ABSTRACT

    CFD case study to optimize surgical adjustment of ventricular assist device implantation to minimize stroke risk part I: steady-state CFD modeling

    Andres F. Osorio1, Ruben Osorio1, Reginald Tran1, Andres Ceballos1, Alain Kassab1, Eduardo Divo2, I. Ricardo Argueta-Morales3, William M. DeCampli3,4

    The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.4, pp. 123-124, 2010, DOI:10.3970/icces.2010.015.123

    Abstract Presently, mechanical support is the most promising alternative to cardiac transplantation. Ventricular Assist Devices (VADs) were originally used to provide mechanical circulatory support in patients waiting planned heart transplantation (“bridge-to-transplantation” therapy). The success of short-term bridge devices led to clinical trials evaluating the clinical suitability of long-term support (“destination” therapy) with left ventricular assist devices (LVADs). The first larger-scale, randomized trial that tested long-term support with a LVAD reported a 44% reduction in the risk of stroke or death in patients with a LVAD. In spite of the success of LVADs as bridge-to-transplantation and long-term support. Patients carrying these devices… More >

  • Open Access

    ARTICLE

    Optimization Algorithm for Reduction the Size of Dixon Resultant Matrix: A Case Study on Mechanical Application

    Shang Zhang1, *, Seyedmehdi Karimi2, Shahaboddin Shamshirband3, 4, *, Amir Mosavi5,6

    CMC-Computers, Materials & Continua, Vol.58, No.2, pp. 567-583, 2019, DOI:10.32604/cmc.2019.02795

    Abstract In the process of eliminating variables in a symbolic polynomial system, the extraneous factors are referred to the unwanted parameters of resulting polynomial. This paper aims at reducing the number of these factors via optimizing the size of Dixon matrix. An optimal configuration of Dixon matrix would lead to the enhancement of the process of computing the resultant which uses for solving polynomial systems. To do so, an optimization algorithm along with a number of new polynomials is introduced to replace the polynomials and implement a complexity analysis. Moreover, the monomial multipliers are optimally positioned to multiply each of the… More >

  • Open Access

    ARTICLE

    A Case Study on Mud-Weight Design with Finite-Element Method for Subsalt Wells

    X.P. Shen, A. Diaz1, T. Sheehy2

    CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 205-224, 2010, DOI:10.3970/cmc.2010.020.205

    Abstract This paper presents a case study for the design of a mud-weight window (MWW) with three-dimensional (3-D), finite-element (FE) tools for subsalt wells. The trajectory of the target well penetrates a 7 km thick salt body. A numerical scheme has been proposed for calculating the shear failure gradient (SFG) and fracture gradient (FG) with 3-D FE software. User subroutines have been developed to address non-uniform pore-pressure distribution. A series of FE calculations were performed to obtain the MWW of the target wellbore, which consists of the SFG and FG for the subsalt sections. Although no reverse faulting structure exists in… More >

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