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K-Ar Dating of Fault Gouges from the Red River Fault Zone of Vietnam

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Acta Geologica Sinica(English Edition) 2016年第5期90卷 1653-1663页

作者： BUI Hoang Bac NGO xuan Thanh Yungoo SONG Tetsumaru ITAYA Koshi YAGI KHUONG The hung nguyen Tien Dung Faculty of Geosciences and Geoengineering Hanoi University of Mining and Geology Duc Thang Bac Tu Liem Hanoi Vietnam Department of Earth System Sciences Yonsei University 50 Yonsei-ro Seoul 120-749 Republic of Korea Japan Geochronology Network (NPO) 2-5 Nakashima Naka-ku Okayama 703-8252 Japan Hiruzen Institute for Geology and Chronology Co. Ltd. 2-5 Nakashima Nakaku Okayama 703-8252 Japan

Constraining the timing of fault zone formation is fundamentally important in terms of geotectonics to understand structural evolution and brittle fault *** paper presents the first authigenic illite K-Ar age data from fault gouge samples collected from the Red River Shear Zone at Lao Cai province,*** fault gouge samples were separated into three grain-size fractions（〈0.1 μm,0.1-0.4 μm and 0.4-1.0 μm）.The results show that the K-Ar age values decrease from coarser to finer grain fractions（24.1 to 19.2 Ma）,suggesting enrichment in finer fraction of morerecently grown authigenic *** timing of the fault movement are the lower intercept ages at 0%detrital illite（19.2 ± 0.92 Ma and 19.4 ± 0.49 Ma）.In combination with previous geochronological data,this result indicates that the metamorphism of the Day Nui Con Voi（DNCV） metamorphic complex took place before ca.26.8 *** about 26.8 Ma-25 Ma,the fault strongly acted to cause the rapid exhumation of the rocks along the Red River-Ailoa Shan Fault Zone（RR-ASFZ）.During brittle deformation,the DNCV slowly uplifted,implying weak movement of the *** brittle deformation might have lasted for ca.5 Ma.

关键词： illite K-Ar dating Red River Fault Zone polytype gouge authigenitic

Enhancing compressive strength and durability of self-compacting concrete modified with controlled-burnt sugarcane bagasse ash-blended cements

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Frontiers of Structural and Civil Engineering 2022年第2期16卷 161-174页

作者： Duc-Hien LE Yeong-Nain SHEEN Khanh-hung nguyen Sustainable Developments in Civil Engineering Research Group Faculty of Civil EngineeringTon Duc Thang UniversityHo Chi Minh City700000Vietnam Department of Civil Engineering Kaohsiung University of Science and TechnologyKaohsiung80778China Department of Civil Engineering Lac Hong UniversityBien Hoa810000Vietnam

In sugar industries,the growing amount of sugarcane bagasse ash(SBA),a byproduct released after burning bagasse for producing electricity,is currently causing environmental *** residual ash displays a pozzolanic potential;and hence,it has potential as a cement *** study focuses on enhancing suitability of SBA through incorporating ground blast furnace slag(BFS)in manufacturing self-compacting concretes(SCCs).For this purpose,SBA was processed by burning at 700°C for 1 h,before being ground to the cement fineness of 4010 cm2/*** mixtures were prepared by changing the proportions of SBA and BFS(i.e.,10%,20%,and 30%)in blended systems;and their performance was *** results showed that the presence of amorphous silica was detected for the processed SBA,revealing that the strength activity index was above 80%.The compressive strength of SCC containing SBA(without BFS)could reach 98%–127%of that of the control;combination of SBA and 30%BFS gets a similar strength to the control after 28 *** durability,the 10%SBA+30%BFS mix exhibited the lowest risk of ***,the joint use of SBA and BFS enhanced significantly the SCC’s sulfate ***,a hyperbolic formula for interpolating the compressive strength of the SBA-based SCC was proposed and validated with error range estimated within±10%.

关键词： sugarcane bagasse ash self-compacting concrete compressive strength sulfate resistance water absorption strength formula

Predicting roof displacement of roadways in underground coal mines using adaptive neuro-fuzzy inference system optimized by various physics-based optimization algorithms

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第6期13卷 1452-1465页

作者： Chengyu Xie Hoang nguyen xuan-Nam Bui Van-Thieu nguyen Jian Zhou School of Environment and Resources Xiangtan UniversityXiangtan411105China Mining Faculty Hanoi University of Mining and GeologyHanoi100000Viet Nam Innovations for Sustainable and Responsible Mining(ISRM)Group Hanoi University of Mining and GeologyHanoi100000Viet Nam Artificial Intelligence Independent Research Group Hanoi100000Viet Nam School of Resources and Safety Engineering Central South UniversityChangsha410083China

Due to the rapid industrialization and the development of the economy in each country,the demand for energy is increasing *** coal mines have to pace up the mining operations with large production to meet the energy *** requirement has led underground coal mines to go deeper with more difficult conditions,especially the mining hazards,such as large deformations,rockburst,coal burst,roof collapse,to name a ***,this study aims at investigating and predicting the stability of the roadways in underground coal mines exploited by longwall mining method,using various novel intelligent techniques based on physics-based optimization algorithms(***-verse optimizer(MVO),equilibrium optimizer(EO),simulated annealing(SA),and Henry gas solubility optimization(HGSO)) and adaptive neuro-fuzzy inference system(ANFIS),named as MVO-ANFIS,EO-ANFIS,SA-ANFIS and HGSOANFIS ***,162 roof displacement events were investigated based on the characteristics of surrounding rocks,such as cohesion,Young’s modulus,density,shear strength,angle of internal friction,uniaxial compressive strength,quench durability index,rock mass rating,and tensile *** MVO-ANFIS,EO-ANFIS,SA-ANFIS and HGSO-ANFIS models were then developed and evaluated based on this dataset for predicting roof displacements in roadways of underground *** results indicated that the proposed intelligent techniques could accurately predict the roof displacements in roadways of underground mines with an accuracy in the range of 83%-92%.Remarkably,the SA-ANFIS model yielded the most dominant accuracy(i.e.92%).Based on the accurate predictions from the proposed techniques,the reinforced solutions can be timely suggested to ensure the stability of roadways during exploiting coal,especially in the underground coal mines exploited by the longwall mining.

关键词： Roof displacement Longwall mining Underground mine Physics-based optimization Risk assessment Mining hazards

Engine performance and combustion characteristics of a direct injection compression ignition engine fueled waste cooking oil synthetic diesel

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International Journal of Coal Science & Technology 2020年第3期7卷 560-570页

作者： Thanh Viet nguyen Khanh Duc nguyen Nang xuan Ho Vinh Duy nguyen Department of Internal Combustion Engine School of Transportation EngineeringHanoi University of Science and TechnologyHanoiViet Nam Faculty of Vehicle and Energy Engineering Phenikaa UniversityYen NghiaHa-Dong DistrictHanoiViet Nam

Biodiesels produced from various feedstocks have been considered as alternative fuels used in internal combustion engines without major *** research focuses on producing biodiesel from waste cooking oil(WCOSD)by the catalytic cracking method using MgO as the catalyst and comparing the engine operating characteristics of the test engine when using WCOSD and traditional diesel(CD)as test *** a result,the brake power of the test engine fueled WCOSD,and traditional diesel is ***,the engine fuel consumption in the case of using WCOSD is slight increases in some operating ***,the nitrogen oxides emissions of the test engine fueled WCOSD are higher than those of CD at all tested *** trend is opposite for hydrocarbon emission as the HC emission of the engine fueled by WCOSD reduces 26.3%on *** smoke emission of the test engine in case of using WCOSD is lower 17%on average than that of ***,the carbon monoxide emissions are lower at the low and medium loads and higher at the full *** results show that the new biodiesel has the same characteristics as those of commercial biodiesel and can be used as fuel for diesel engines.

关键词： Feedstock Waste cooking oil Engine characteristics Exhaust missions Ignition timing Fuel consumption

Novel Soft ComputingModel for Predicting Blast-Induced Ground Vibration in Open-Pit Mines Based on the Bagging and Sibling of Extra Trees Models

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Computer Modeling in Engineering & Sciences 2023年第3期134卷 2227-2246页

作者： Quang-Hieu Tran Hoang nguyen xuan-Nam Bui Department of Surface Mining Mining FacultyHanoi University of Mining and GeologyHanoi100000Vietnam Innovations for Sustainable and Responsible Mining(ISRM)Research Group Hanoi University of Mining and GeologyHanoi100000Vietnam

This study considered and predicted blast-induced ground vibration(PPV)in open-pit mines using bagging and sibling techniques under the rigorous combination of machine learning ***,four machine learning algorithms,including support vector regression(SVR),extra trees(ExTree),K-nearest neighbors(KNN),and decision tree regression(DTR),were used as the base models for the purposes of combination and PPV initial *** bagging regressor(BA)was then applied to combine these base models with the efforts of variance reduction,overfitting elimination,and generating more robust predictive models,abbreviated as BA-ExTree,BAKNN,BA-SVR,and *** is emphasized that the ExTree model has not been considered for predicting blastinduced ground vibration before,and the bagging of ExTree is an innovation aiming to improve the accuracy of the inherently ExTree model,as *** addition,two empirical models(i.e.,USBM and Ambraseys)were also treated and compared with the bagging models to gain a comprehensive *** this aim,we collected 300 blasting events with different parameters at the Sin Quyen copper mine(Vietnam),and the produced PPV values were also *** were then compiled as the dataset to develop the PPV predictive *** results revealed that the bagging models provided better performance than the empirical models,except for the BA-DTR *** those,the BA-ExTree is the best model with the highest accuracy(i.e.,88.8%).Whereas,the empirical models only provided the accuracy from 73.6%–76%.The details of comparisons and assessments were also presented in this study.

关键词： Mine blasting blast-induced ground vibration environmentally friendly blasting peak particle velocity bagging extra trees

Three-Dimensional Meshfree Analysis of Interlocking Concrete Blocks for Step Seawall Structure

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Computers, Materials & Continua 2021年第1期66卷 165-178页

作者： Hau nguyen-Ngoc Hnguyen-xuan Magd Abdel-Wahab Soete Laboratory Faculty of Engineering and ArchitectureGhent UniversityTechnologiepark Zwijnaarde 903B-9052ZwijnaardeBelgium University of Science and Technology The University of DanangDa Nang CityVietnam CIRTech Institute Ho Chi Minh City University of TechnologyHo Chi Minh CityVietnam Division of Computational Mechanics Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityVietnam

This study adapts the flexible characteristic of meshfree method in analyzing three-dimensional(3D)complex geometry structures,which are the interlocking concrete blocks of step *** elastostatic behavior of the block is analysed by solving the Galerkin weak form formulation over local support *** 3D moving least square(MLS)approximation is applied to build the interpolation functions of *** pre-defined number of nodes in an integration domain ranging from 10 to 60 nodes is also investigated for their effect on the studied *** accuracy and efficiency of the studied method on 3D elastostatic responses are validated through the comparison with the solutions of standard finite element method(FEM)using linear shape functions on tetrahedral elements and the well-known commercial software,*** results show that elastostatic responses of studied concrete block obtained by meshfree method converge faster and are more accurate than those of standard *** studied meshfree method is effective in the analysis of static responses of complex geometry *** amount of discretised nodes within the integration domain used in building MLS shape functions should be in the range from 30 to 60 nodes and should not be less than 20 nodes.

关键词： Meshfree method local support domain moving least square shape function 3D elastostatic behavior complex geometry

Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

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International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： nguyen Thi Thanh Thao Dao nguyen Khoi Tran Thanh xuan Bernard Tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam NTT Institute of Hi-Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that Quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

On Huppert＇s Conjecture for Alternating Groups of Low Degrees

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Algebra Colloquium 2015年第2期22卷 293-308页

作者： hung Ngoc nguyen hung P. Tong-Viet Thomas P. Wakefield Department of Mathematics The University of Akron Akron Ohio 44325 USA School of Mathematical Sciences. North-West University (Mafikeng Campus) Mmabatho 2735 South Africa Department of Mathematics and Statistics Youngstown State University One University Plaza Youngstown Ohio 44555 USA

Bertram Huppert conjectured in the late 1990s that the nonabelian simple groups are determined up to an abelian direct factor by the set of their character degrees. Although the conjecture has been established for various simple groups of Lie type and simple sporadic groups, it is expected to be difficult for alternating groups. In [5], Hup- pert verified the conjecture for the simple alternating groups AN of degree up to 11. In this paper, we continue his work and verify the conjecture for the alternating groups of degrees 12 and 13.

关键词： alternating groups character degrees

Single-Layer Wideband Circularly Polarized Antenna Using Non-Uniform Metasurface for C-band Applications

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Computers, Materials & Continua 2021年第8期68卷 2487-2498页

作者： Huy hung Tran Khoa nguyen-Dang Niamat Hussain Faculty of Electrical and Electronic Engineering PHENIKAA UniversityHanoi12116Vietnam PHENIKAA Research and Technology Institute(PRATI) A&A Green Phoenix Group JSCCau Giay11313HanoiVietnam Department of Computer and Communication Engineering Chungbuk National UniversityCheongju 28644Korea

A single-layer design of non-uniform metasurface(MS)based circularly polarized(CP)antenna with wideband operation characteristic is proposed and investigated in this *** antenna is excited by a truncated corner squared patch as a primary radiating CP ***,a non-uniform MS is placed in the same layer with the driven *** increasing the impedance bandwidth,the non-uniform MS also generates two additional CP bands in the high frequency band,leading to significantly increase the antenna’s overall *** use of non-uniform MS distinguishes our design from the other CP MS based antennas in literature,in which the MS is formed by multiple uniform unit cells and placed in different layer with the radiating *** validation,an antenna prototype,whose overall dimensions of 0.94λ_(o)×0.94λ_(o)×0.06λ_(o) at the center operating frequency,is fabricated and experimentally *** measured operating bandwidth with|S11|≤−10 dB and AR≤3 dB is 27.1%(5.1–6.7 GHz)and the broadside gain within this band is from 5.7 to 7.2 *** to the other related works,the proposed antenna has advantage of very wideband operation with single-layer design.

关键词： Circular polarization metasurface non-uniform patch antenna wideband