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Development of a time-dependent energy model to calculate the mining-induced stress over gates and pillars

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 306-317页

作者： Mohammad Rezaei Mohammad Farouq Hossaini abbas majdi School of Mining Engineering College of Engineering University of Tehran

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.

关键词： Longwall mining Strain energy Time-dependent model Destressed zone Mining-induced stress

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碳酸盐岩储集层岩石物性变化与结构变形实验

石油勘探与开发 2019年第3期46卷 542-551页

作者： SALIMIDELSHAD Yaser MORADZADEH Ali KAZEMZADEH Ezatallah POURAFSHARY Peyman majdi abbas School of Mining Engineering College of Engineering University of Tehran Faculty of Research and Development in Upstream Petroleum Industry Research Institute of Petroleum IndustryTehran Department of Petroleum Engineering School of Mining and Geosciences Nazarbayev University

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... 详细信息

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。

关键词：压力循环加载岩石物性碳酸盐岩储集层 CT扫描 South-Pars气田下三叠统Kangan组结构变形

Experimental investigation of changes in petrophysical properties and structural deformation of carbonate reservoirs

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Petroleum Exploration and Development 2019年第3期46卷 565-575页

作者： SALIMIDELSHAD Yaser MORADZADEH Ali KAZEMZADEH Ezatallah POURAFSHARY Peyman majdi abbas School of Mining Engineering College of Engineering University of Tehran Tehran *** Iran Faculty of Research and Development in Upstream Petroleum Industry Research Institute of Petroleum Industry Tehran *** Iran Department of Petroleum Engineering School of Mining and Geosciences Nazarbayev University Astana 010000 Kazakhstan

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.

关键词： cyclic pressure loading petrophysical property carbonate reservoir, CT scan rock physical property structure deformation

Expanding role of antibodies in kidney transplantation

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World Journal of Transplantation 2025年第1期15卷 57-71页

作者： Khawar abbas Muhammed Mubarak Department of Transplant Immunology Sindh Institute of Urology&TransplantationKarachi 74200SindhPakistan Javed I.Kazi Department of Histopathology Sindh Institute of Urology&TransplantationKarachi 74200SindhPakistan

The role of antibodies in kidney transplant(KT)has evolved significantly over the past few *** role of antibodies in KT is multifaceted,encompassing both the challenges they pose in terms of antibody-mediated rejection(AMR)and the opportunities for improving transplant outcomes through better detection,prevention,and treatment *** our understanding of the immunological mechanisms continues to evolve,so too will the approaches to managing and harnessing the power of antibodies in KT,ultimately leading to improved patient and graft *** narrative review explores the multifaceted roles of antibodies in KT,including their involvement in rejection mechanisms,advancements in desensitization protocols,AMR treatments,and their potential role in monitoring and improving graft survival.

关键词： Antibodies Humoral theory Kidney transplantation Rejection

Experiments on image data augmentation techniques for geological rock type classification with convolutional neural networks

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Journal of Rock Mechanics and Geotechnical Engineering 2025年第1期17卷 106-125页

作者： Afshin Tatar Manouchehr Haghighi abbas Zeinijahromi School of Chemical Engineering Discipline of Mining and Petroleum EngineeringThe University of AdelaideAdelaideSA 5005Australia

The integration of image analysis through deep learning(DL)into rock classification represents a significant leap forward in geological *** traditional methods remain invaluable for their expertise and historical context,DL offers a powerful complement by enhancing the speed,objectivity,and precision of the classification *** research explores the significance of image data augmentation techniques in optimizing the performance of convolutional neural networks(CNNs)for geological image analysis,particularly in the classification of igneous,metamorphic,and sedimentary rock types from rock thin section(RTS)*** study primarily focuses on classic image augmentation techniques and evaluates their impact on model accuracy and *** demonstrate that augmentation techniques like Equalize significantly enhance the model's classification capabilities,achieving an F1-Score of 0.9869 for igneous rocks,0.9884 for metamorphic rocks,and 0.9929 for sedimentary rocks,representing improvements compared to the baseline original ***,the weighted average F1-Score across all classes and techniques is 0.9886,indicating an ***,methods like Distort lead to decreased accuracy and F1-Score,with an F1-Score of 0.949 for igneous rocks,0.954 for metamorphic rocks,and 0.9416 for sedimentary rocks,exacerbating the performance compared to the *** study underscores the practicality of image data augmentation in geological image classification and advocates for the adoption of DL methods in this domain for automation and improved *** findings of this study can benefit various fields,including remote sensing,mineral exploration,and environmental monitoring,by enhancing the accuracy of geological image analysis both for scientific research and industrial applications.

关键词： Deep learning(DL) Image analysis Image data augmentation Convolutional neural networks(CNNs) Geological image analysis Rock classification Rock thin section(RTS)images

Experimental Study of Forced Convective Heat Transfer in a Copper Tube Using Three Types of Nanofluids

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Fluid Dynamics & Materials Processing 2025年第2期21卷 351-370页

作者： Zahraa N.Hussain Jamal M.Ali Hasan S.majdi abbas J.Sultan H.Al-Naseri Department of Chemical Engineering University of Technology-IraqBaghdad10066Iraq Department of Chemical Engineering and Petroleum Industries Al-Mustaqbal UniversityBabylon51001Iraq Chemical Engineering Department College of EngineeringTikrit UniversityTikrit34001Iraq

The use of nanofluids as heat transfer media represents an innovative strategy to enhance heat transfer *** study investigates experimentally the turbulent convective heat transfer characteristics of waterbased nanofluids containing TiO_(2),CuO,and graphene nanoplatelet(GNP)nanoparticles as they flow through a copper *** the dynamic viscosity and thermal conductivity of these nanofluids were modeled and experimentally measured across varying nanoparticle concentrations(0.01,0.02,and 0.03 vol.%)and temperatures(25℃,35℃,and 45℃).The findings indicate that the behavior of nanofluids depends on the parameter used for comparison with the base ***,both the friction factor and heat transfer coefficient increase with higher nanoparticle volume concentrations at a constant Reynolds *** results further reveal that the GNP/water nanofluid,with a volume concentration of 0.03%at 45℃,exhibit the highest Nusselt number,followed by the CuO/water and TiO_(2)/water nanofluids,with respective increases of 17.8%,11.09%,and 8.11%.

关键词： Nanofluid heat transfer coefficient thermal conductivity heat transfer enhancement

Transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 177-192页

作者： M.NAVEED M.IMRAN T.ASGHAR Z.abbas Department of Mathematics Division of Science and TechnologyUniversity of Education Department of Mathematics The Islamia University of Bahawalpur

This paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. The influence of magnetic fields is also inspected in terms of their physical characteristics. To depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utilizing a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utilizing the homotopy analysis method(HAM).The effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyzed in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

关键词： analytical solution Cattaneo-Christov heat and mass flux chemical reaction gyrotactic microorganism hybrid nanofluid O368 oscillating curved stretchable sheet

“Superimposed”spectral characteristics of fluorophores arising from cross-conjugation hybridization

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Chinese Chemical Letters 2025年第1期36卷 442-446页

作者： Kai An Qinglong Qiao Lovelesh Syed Ali abbas Abedi Xiaogang Liu Zhaochao Xu CAS Key Laboratory of Separation Science for Analytical Chemistry Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China University of Chinese Academy of Sciences Beijing 100049China Fluorescence Research Group Singapore University of Technology and DesignSingapore 487372Singapore

The demand for enhanced optical properties in advanced fluorescence technologies has driven research into the structure-property relationship of *** this paper,we use naphthalene fluorophores Na DC-Aze and PhDO-Aze as a case study to emphasize the pivotal role of cross conjugation in tuning the optical structure-property *** DC-Aze and PhDO-Aze,formed by hybridizing two distinct conjugated systems in a single naphthalene molecule,exhibit spectral characteristics from both conjugated *** data and theoretical calculations demonstrate the coexistence of two electron-delocalization systems in a cross-conjugation manner in both Na DC-Aze and *** cross-conjugation fluorophores exhibit high brightness,large Stokes shift,and a broad absorption wavelength range by combining distinct spectral properties from its parent *** spectral properties will be advantageous for certain applications(i.e.,panchromatic absorption in organic solar cells,and fluorophores compatible with a wide range of excitation wavelengths).

关键词： Fluorophore Cross conjugation Absorption Emission Naphthalene

Rainfall-induced wind erosion in soils stabilized with alkali-activated waste materials

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Journal of Rock Mechanics and Geotechnical Engineering 2025年第1期17卷 465-480页

作者： Alireza Komaei abbas Soroush Seyed Mohammad Fattahi Hesam Ghanbari Department of Civil and Environmental Engineering Amirkabir University of TechnologyTehran159163431Iran

This study evaluates the efficacy of sustainable erosion control using slag-based alkali-activated cement crusts under varying rainfall and wind conditions. The rainfall intensities ranged from 30 mm/h to 120 mm/h, with durations ranging from 15 min to 90 min, and crust slopes of ∼2° (gentle) and 30° (steep). Wind tunnel experiments were conducted at wind velocities of 14 m/s, 21 m/s, and 28 m/s to investigate post-rainfall wind erodibility, along with changes in crust strength and microstructure analysis. The findings show the development of hydrated cementitious phases in alkali-activated material, which form around and between the particles during the alkaline activation process. Alkali-activated cement crusts significantly reduced erosion caused by rainfall and subsequent wind by several orders of magnitude. At the highest rainfall intensity of 120 mm/h, rainfall erosion was measured to be 1654.81 kg/m2 for untreated samples and 0.89 kg/m2 for treated samples, demonstrating a substantial 99.95% reduction in erosion due to the treatment. Similarly, at the highest wind speed tested, wind erosion was 122.75 kg/m2 for untreated samples and 0.095 kg/m2 for treated samples, indicating a significant 99.92% reduction in erosion due to the formation of an alkali-activated cement crust on the soil surface. However, exposure of the samples to 120 mm/h rainfall for 90 min resulted in a 5.2-fold increase in wind erosion compared to pre-rainfall conditions. Similarly, penetrometer results indicated a 37%–54% reduction in post-rainfall surface strength.

关键词： Rainfall erosion Alkali-activated material Wind erosion Crust formation