Extended two-body problem for rotating rigid bodies     

Ho  Alex  Wold  Margrethe  Conway  John T.  Poursina  Mohammad 《Celestial Mechanics and Dynamical Astronomy》2021,133(8):1-44

Given the interest in future space missions devoted to the exploration of key moons in the solar system and that may involve libration point orbits, an efficient design strategy for transfers between moons is introduced that leverages the dynamics in these multi-body systems. The moon-to-moon analytical transfer (MMAT) method is introduced, comprised of a general methodology for transfer design between the vicinities of the moons in any given system within the context of the circular restricted three-body problem, useful regardless of the orbital planes in which the moons reside. A simplified model enables analytical constraints to efficiently determine the feasibility of a transfer between two different moons moving in the vicinity of a common planet. In particular, connections between the periodic orbits of such two different moons are achieved. The strategy is applicable for any type of direct transfers that satisfy the analytical constraints. Case studies are presented for the Jovian and Uranian systems. The transition of the transfers into higher-fidelity ephemeris models confirms the validity of the MMAT method as a fast tool to provide possible transfer options between two consecutive moons.

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Bearing capacity performance of soft cohesive soil treated by kenaf limited life geotextile     

Ahmad Safuan A Rashid  Mohammad Gharehzadeh Shirazi  Ramli Nazir  Hisham Mohamad  Fauzan Sahdi 《Marine Georesources & Geotechnology》2020,38(6):755-760

Abstract

This article presents the performance of the short-term bearing capacity on soft clay soil treated by Kenaf geotextile under vertical loading via a small-scale modelling test at unit gravity. The ground model was formulated by consolidating kaolin in a rigid testing compartment. In the loading test, the strip footing was represented by a rigid footing. For the treated case, a series of tests were performed to examine the effects of the burial depth of the Kenaf geotextile on the bearing capacity of the soft soil. The Kenaf geotextile was laid beneath the rigid footing (at the ground surface) and at 50, 75 and 100?mm depth from the soil surface. All the measured results of the Kenaf geotextile treated ground were compared with the untreated ground. The incorporation of Kenaf fibre geotextile was observed to enhance the bearing capacity of soft cohesive clay up to 281% depending upon the depth of the installed geotextile. The geotextile at the surface provided the highest bearing capacity and sustained the highest displacement at failure. The outcome of this research will promote the use of natural fibre geotextiles as sustainable earth reinforcement in temporary earthwork applications.  相似文献   

Assessing the effect of temporal dynamics on urban growth simulation: Towards an asynchronous cellular automata     

Somaie Abolhasani  Mohammad Taleai 《Transactions in GIS》2020,24(2):332-354

Time is a fundamental dimension in urban dynamics, but the effect of various definitions of time on urban growth models has rarely been evaluated. In urban growth models such as cellular automata (CA), time has typically been defined as a sequence of discrete time steps. However, most urban growth processes such as land‐use changes are asynchronous. The aim of this study is to examine the effect of various temporal dynamics scenarios on urban growth simulation, in terms of urban land‐use planning, and to introduce an asynchronous parcel‐based cellular automata (AParCA) model. In this study, eight different scenarios were generated to investigate the impact of temporal dynamics on CA‐based urban growth models, and their outputs were evaluated using various urban planning indicators. The obtained results show that different degrees of temporal dynamics lead to various patterns appearing in urban growth CA models, and the application of asynchronous (event‐driven) CA models achieves better simulation results than synchronous models.  相似文献   

3D Geomechanical Modeling of Casing Collapse in Plastic Formations (Cap Rock of Hydrocarbon Reservoir)     

Hedayatikhah  Soheila  Abdideh  Mohammad 《Natural Resources Research》2019,28(1):273-286

Natural Resources Research - In the Gachsaran Formation, the casing pipes driven into a number of wells have collapsed within a short span of time in one of the southwest fields of Iran. The casing...  相似文献   

ANN-Based Prediction of Laboratory-Scale Performance of CO2-Foam Flooding for Improving Oil Recovery     

Moosavi  Seyedeh Raha  Wood  David A.  Ahmadi  Mohammad Ali  Choubineh  Abouzar 《Natural Resources Research》2019,28(4):1619-1637

Natural Resources Research - Improving oil recovery by CO2 injection continues to gain momentum in mature oil fields due to its favorable industrial and environmental benefits. One remediation for...  相似文献   

Towards simulation of 3D nonlinear high-speed vessels motion     

Roozbeh Panahi  Ebrahim Jahanbakhsh  Mohammad Saeed Seif 《Ocean Engineering》2009,36(3-4):256-265

A numerical simulation algorithm based on the finite volume discretisation is presented for analyzing ship motions. The algorithm employs a fractional step method to deal with the coupling between the pressure and velocity fields. The free surface capturing is fulfilled by using a volume of fluid method in which the interface between the liquid (water) and gas (air) phases are computed by solving a scalar transport equation for the volume fraction of the liquid phase. The computed velocity field is employed to evaluate the acting forces and moments on the vessel. Using the strategy of boundary-fitted body-attached mesh and calculating all six degrees-of-freedom of motion in each time step, time history of ship motions including displacements, velocities and accelerations are evaluated.To verify the proposed algorithm, a series of verification tests are conducted. First, a two-dimensional asymmetrical wedge slamming is simulated as a simple type of a common case for high-speed vessels. Then, the steady-state forward motion of a high-speed planing catamaran is investigated. Results of both test cases show good agreement with experimental data. It is concluded that the proposed algorithm can be a promising strategy for both performance prediction and design of high-speed vessels.  相似文献   

A Unified Computational Method for Simulating Dynamic Behavior of Planing Vessels     

Mohammad Saeed SEIF  Ebrahim JAHANBAKHSH  Roozbeh PANAHI  Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528

High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f...  相似文献   

Modeling the near-field effects of the worst-case tsunami in the Makran subduction zone   总被引：1，自引：0，他引：1  

Mohammad Heidarzadeh  Moharram D. Pirooz 《Ocean Engineering》2009,36(5):368-28

As a first step towards the development of inundation maps for the northwestern Indian Ocean, we simulated the near-field inundation of two large tsunami in the Makran subduction zone (MSZ). The tsunami scenarios were based on large historical earthquakes in the region. The first scenario included the rupture of about 500 km of the plate boundary in the eastern MSZ, featuring a moment magnitude of M_w 8.6. The second scenario involved the full rupture of the plate boundary resulting from a M_w 9 earthquake. For each scenario, the distribution of tsunami wave height along the coastlines of the region is presented. Also, detailed runup modeling was performed at four main coastal cities in the region for the second scenario. To investigate the possible effect of splay fault branching on tsunami wave height, a hypothetical splay fault was modeled which showed that it can locally increase the maximum wave height by a factor of 2. Our results showed that the two tsunami scenarios produce a runup height of 12-18 m and 24-30 m, respectively. For the second scenario, the modeled inundation distance was between 1 and 5 km.  相似文献   

Correction to: Geomorphic investigation of the Late-Quaternary landforms in the southern Zanskar Valley,NW Himalaya     

Shubhra Sharma  Aadil Hussain  Amit K Mishra  Aasif Lone  Tarun Solanki  Mohammad Khatib Khan 《Journal of Earth System Science》2018,127(2):31

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Evaluation of radiation methods to study potential evapotranspiration of 31 provinces   总被引：1，自引：1，他引：0  

Mohammad Valipour 《Meteorology and Atmospheric Physics》2015,127(3):289-303

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