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| 1 | Development of a time-dependent energy model to calculate the mining-induced stress over gates and pillars显示文摘Generally, longwall mining-induced stress results from the stress relaxation due to destressed zone that occurs above the mined panel. Knowledge of induced stress is very important for accurate design of adjacent gateroads and intervening pillars which helps to raise the safety and productivity of longwall mining operations. This study presents a novel time-dependent analytical model for determination of the longwall mining-induced stress and investigates the coefficient of stress concentration over adjacent gates and pillars. The model is developed based on the strain energy balance in longwall mining incorporated to a rheological constitutive model of caved materials with time-varying parameters. The study site is the Tabas coal mine of Iran. In the proposed model, height of destressed zone above the mined panel, total longwall mining-induced stress, abutment angle, induced vertical stress, and coefficient of stress concentration over neighboring gates and intervening pillars are calculated. To evaluate the effect of proposed model parameters on the coefficient of stress concentration due to longwall mining, sensitivity analysis is performed based on the field data and experimental constants. Also, the results of the proposed model are compared with those of existing models. The comparative results confirm a good agreement between the proposed model and the in situ measurements. According to the obtained results, it is concluded that the proposed model can be successfully used to calculate the longwall mining-induced stress. Therefore, the optimum design of gate supports and pillar dimensions would be attainable which helps to increase the mining efficiency. | Mohammad Rezaei Mohammad Farouq Hossaini Abbas Majdi | 2015 | Journal of Rock Mechanics and Geotechnical Engineering2015，7，3： | 6 |
| 2 | Prediction of representative deformation modulus of longwall panel roof rock strata using Mamdani fuzzy system显示文摘Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining structures. In this paper, two predictive models including Mamdani fuzzy system(MFS) and multivariable regression analysis(MVRA) were developed to predict deformation modulus based on data obtained from dilatometer tests carried out in Bakhtiary dam site and additional data collected from longwall coal mines. Models inputs were considered to be rock quality designation, overburden height, weathering,unconfined compressive strength, bedding inclination to core axis, joint roughness coefficient and fill thickness. To control the models performance, calculating indices such as root mean square error(RMSE),variance account for(VAF) and determination coefficient(R2) were used. The MFS results show the significant prediction accuracy along with high performance compared to MVRA results. Finally, the sensitivity analysis of MFS results shows that the most and the least effective parameters on deformation modulus are weathering and overburden height, respectively. | Mohammad Rezaei Mostafa Asadizadeh Abbas Majdi Mohammad Farouq Hossaini | 2015 | International Journal of Mining Science and Technology2015，25，1： | 6 |
| 3 | Experimental investigation of changes in petrophysical properties and structural deformation of carbonate reservoirs显示文摘To examine the effect of pressure on pore structure and petrophysical properties of carbonate rock, the porosity, permeability, CT scanning, SEM and elastic wave velocity of two carbonate core plug samples from an oilfield in Southwest Iran were analyzed under cyclic pressure. One of the plugs was calcite and the other was dolomite with anhydrite nodules. The cyclic pressure exerted on the samples increased from 13.79 MPa to 27.58 MPa in six steps, and the variations in petrophysical properties of the two samples at different pressure loading and unloading steps were counted and analyzed. The results show that the calcite sample decreases in porosity and permeability with the increase of pressure, which is consistent with the results from compression and shear wave velocity tests. In the dolomite sample, the decreasing trend was not observed;fluctuations of compressive and shear velocities were observed during the loading stage, which may be due to different geometries of the pores and the porosity variation in the sample. Understanding the variation of carbonate petrophysical properties with pressure is helpful for optimizing reservoir development scheme. | SALIMIDELSHAD Yaser MORADZADEH Ali KAZEMZADEH Ezatallah POURAFSHARY Peyman MAJDI Abbas | 2019 | Petroleum Exploration and Development2019，46，3： | 2 |
| 4 | Prediction of the height of destressed zone above the mined panel roof in longwall coal mining显示文摘 | Abbas Majdi Feni P Hassani Mehdi Yousef Nasiri | 2012 | International Journal of Coal Geology2012，98，1： | 1 |
| 5 | Prediction of the height of destressed zone above the mined panel roof in longwall coal mining显示文摘 | Abbas Majdi Ferri P. Hassani Mehdi Yousef Nasiri | 2012 | International Journal of Coal Geology2012，，： | 1 |
| 6 | A time-independent energy model to determine the height of dis- tressed zone above the mined panel in longwall coal mining 显示文摘 | Mohammad Rezaei Mohammad Farouq Hossaini Abbas Majdi | 2015 | Tunnelling and Underground Space Technology2015，47，： | 1 |
| 7 | Stability Analysis of Rock Slopes Against Block-Flexure Toppling Failure显示文摘 | Mehdi Amini Abbas Majdi Mohammad Amin Veshadi | 2012 | Rock Mech Rock Eng2012，28，1： | 1 |
| 8 | Stability Analysis of Rock Slopes Against Block - Flexure toppling Failure 显示文摘 | Mehdi Amini Abbas Majdi Mohammad Amin Veshadi | 2012 | Rock Mechanics Rock Engineering2012，，1： | 1 |
| 9 | Flow Regimes in Bubble Columns with and without Internals: A Review显示文摘Hydrodynamics characterization in terms offlow regime behavior is a crucial task to enhance the design of bubble column reactors and scaling up related methodologies.This review presents recent studies on the typicalflow regimes established in bubble columns.Some effort is also provided to introduce relevant definitions pertaining to thisfield,namely,that of“void fraction”and related(local,chordal,cross-sectional and volumetric)variants.Experimental studies involving different parameters that affect design and operating conditions are also discussed in detail.In the second part of the review,the attention is shifted to cases with internals of various types(perfo-rated plates,baffles,vibrating helical springs,mixers,and heat exchanger tubes)immersed in the bubble columns.It is shown that the presence of these elements has a limited influence on the global column hydrodynamics.However,they can make the homogeneousflow regime more stable in terms of transition gas velocity and transi-tion holdup value.The last section is used to highlight gaps which have not beenfilled yet and future directions of investigation. | Ayat N.Mahmood Amer A.Abdulrahman Laith S.Sabri Abbas J.Sultan Hasan Shakir Majdi Muthanna H.Al-Dahhan | 2024 | Fluid Dynamics & Materials Processing2024，20，2： | 0 |
| 10 | Deep Transfer Learning-Enabled Activity Identification and Fall Detection for Disabled People显示文摘The human motion data collected using wearables like smartwatches can be used for activity recognition and emergency event detection.This is especially applicable in the case of elderly or disabled people who live self-reliantly in their homes.These sensors produce a huge volume of physical activity data that necessitates real-time recognition,especially during emergencies.Falling is one of the most important problems confronted by older people and people with movement disabilities.Numerous previous techniques were introduced and a few used webcam to monitor the activity of elderly or disabled people.But,the costs incurred upon installation and operation are high,whereas the technology is relevant only for indoor environments.Currently,commercial wearables use a wireless emergency transmitter that produces a number of false alarms and restricts a user’s movements.Against this background,the current study develops an Improved WhaleOptimizationwithDeep Learning-Enabled Fall Detection for Disabled People(IWODL-FDDP)model.The presented IWODL-FDDP model aims to identify the fall events to assist disabled people.The presented IWODLFDDP model applies an image filtering approach to pre-process the image.Besides,the EfficientNet-B0 model is utilized to generate valuable feature vector sets.Next,the Bidirectional Long Short Term Memory(BiLSTM)model is used for the recognition and classification of fall events.Finally,the IWO method is leveraged to fine-tune the hyperparameters related to the BiLSTM method,which shows the novelty of the work.The experimental analysis outcomes established the superior performance of the proposed IWODL-FDDP method with a maximum accuracy of 97.02%. | Majdy M.Eltahir Adil Yousif Fadwa Alrowais Mohamed K.Nour Radwa Marzouk Hatim Dafaalla Asma Abbas Hassan Elnour Amira Sayed A.Aziz Manar Ahmed Hamza | 2023 | Computers, Materials & Continua2023，，5： | 0 |
| 11 | 碳酸盐岩储集层岩石物性变化与结构变形实验显示文摘为研究压力对碳酸盐岩孔隙结构、岩石物理性质等方面的影响,在压力循环加载条件下对伊朗西南部South-Pars气田下三叠统Kangan组2个碳酸盐岩柱状岩心样品进行孔隙度、渗透率、CT扫描、扫描电子显微镜(SEM)、弹性波速度等分析。在2个岩心样品中,一个样品为方解石,另一个为含硬石膏结核的白云石,分别以6个阶段循环施加13.79 MPa和27.58 MPa的负载压力,统计分析2个样品在不同压力加载/卸载阶段下的物性变化特点。结果表明,方解石样品的孔隙度和渗透率随压力载荷的增加而减小,这与纵波和横波速度测试的结果一致。在白云石样品中则没有观察到这种趋势。在纵波和横波速度分析中可观察到压力加载阶段速度发生起伏,这可能是由于孔隙具有不同几何形状和样品中的孔隙发生变化所致。研究碳酸盐岩物性随压力的变化有助于优化调整油气藏开发方案。 | SALIMIDELSHAD Yaser MORADZADEH Ali KAZEMZADEH Ezatallah POURAFSHARY Peyman MAJDI Abbas | 2019 | 石油勘探与开发2019，46，3： | 0 |
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