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Control of settlement and volume loss induced by tunneling under recently reclaimed land

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Underground Space 2019年第4期4卷 289-301页

作者： A.K.L.Kwong C.C.W.ng A.Schwob AECOM Hong KongChina Dragages-Bouygues joint Venture Hong KongChina

The proposed Tuen Mun-Chek Lap Kok Link(TM-CLKL)project comprises a 9-km-long dual two-lane carriageway between Tuen Mun and North Lantau,Hong *** of the two tunnels at the Northern Landfall Fall was carried out by two TBMs:the northbound is referred to as ML03 and has an excavated diameter of 17.63 m,and the southbound is referred to as ML02 and has an excavated diameter of 14.00 *** use of TBMs minimized the amount of dredging and removal of soft marine deposits,resulting in less impact to the environment within and near the work site of the *** treatment in the form of deep vibro-compaction was carried out at the sand fill and band drains installed in the marine deposit.A surcharge was also added above the final formation level to limit the residual settlement and differential settlement of the reclaimed land to less than 500 mm and 1 in 300,respectively,for a design life of 50 *** element analyses were performed to predict the settlement trough under different confinement pressures along the tunnel *** monitoring of the ground movement was carried out during the driving of the two TBMs to ensure that the design confinement pressure of the slurry would not cause excessive settlement,heave,or blow out at the shallow tunnel sections or different facilities along the tunnel *** monitoring data was then used to back-calculate the percentage of volume loss,which is a key index describing the behavior of the ground during *** monitoring data showed that the measured settlement and back-calculated volume loss were much lower than the predicted values.

关键词： TBM excavation Settlement trough Volume loss Ground treatment Confinement pressure

A new green process for biodiesel production from waste oils via catalytic distillation using a solid acid catalyst-Modeling, economic and environmental analysis

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Green Energy & Environment 2016年第1期1卷 62-74页

作者： Aashish Gaurav Flora T.T.ng Garry L.Rempel Department of Chemical Engineering University of Waterloo

The challenges in the chemical processing industry today are environmental concerns, energy and capital costs. Catalytic distillation(CD) is a green reactor technology which combines a catalytic reaction and separation via distillation in the same distillation column. Utilization of CD in chemical process development could result in capital and energy savings, and the reduction of greenhouse gases. The efficacy of CD and the economic merits, in terms of energy and equipment savings, brought by CD for the production of biodiesel from waste oil such as yellow grease is quantified. Process flow sheets for industrial routes for an annual production of 10 million gallon ASTM purity biodiesel in a conventional process(reactor followed by distillation) and CD configurations are modeled in Aspen Plus. Material and energy flows, as well as sized unit operation blocks, are used to conduct an economic assessment of each process. Total capital investment, total operating and utility costs are calculated for each process. The waste oil feedstock is yellow grease containing both triglyceride and free fatty acid. Both transesterification and esterification reactions are considered in the process simulations. Results show a significant advantage of CD compared to a conventional biodiesel processes due to the reduction of distillation columns, waste streams and greenhouse gas emissions. The significant savings in capital and energy costs together with the reduction of greenhouse gases demonstrate that process intensification via CD is a feasible and new green process for the biodiesel production from waste oils.

关键词： Yellow grease Catalytic distillation Aspen plus economic analyzer Process intensification

Ileal-anal pouches: A review of its history, indications, and complications

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World journal of Gastroenterology 2019年第31期25卷 4320-4342页

作者： Kheng-Seong ng Simon joseph Gonsalves Peter Michael Sagar john Goligher Colorectal Unit St.James’s University HospitalLeeds LS9 7TFUnited Kingdom Institute of Academic Surgery University of SydneyCamperdownNew South Wales 2050Australia Department of Colorectal Surgery Huddersfield Royal InfirmaryCalderdale and Huddersfield NHS Foundation TrustHuddersfield HD3 3EAUnited Kingdom

The ileal pouch anal anastomosis(IPAA)has revolutionised the surgical management of ulcerative colitis(UC)and familial adenomatous polyposis(FAP).Despite refinement in surgical technique(s)and patient selection,IPAA can be associated with significant *** the IPAA celebrated its 40th anniversary in 2018,this review provides a timely outline of its history,indications,and *** has undergone significant modification since *** both UC and FAP,IPAA surgery aims to definitively cure disease and prevent malignant degeneration,while providing adequate continence and avoiding a permanent *** majority of patients experience long-term success,but“early”and“late”complications are *** sepsis is a common early complication with far-reaching consequences of long-term pouch dysfunction,but prompt intervention(either radiological or surgical)reduces the risk of pouch *** in the absence of sepsis,pouch dysfunction is a longterm complication that may have a myriad of *** is a common cause that remains incompletely understood and difficult to manage at times.10%of patients succumb to the diagnosis of pouch failure,which is traditionally associated with the need for pouch *** review provides a timely outline of the history,indications,and complications associated with *** selection remains key,and contraindications exist for this surgery.A structured management plan is vital to the successful management of complications following pouch surgery.

关键词： Ileal pouch Restorative proctocolectomy Ulcerative colitis Crohn’s disease Familial adenomatous polyposis

Microstructure and mechanical behavior of laser aided additive manufactured low carbon interstitial Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)multicomponent alloy

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journal of Materials Science & Technology 2021年第18期77卷 38-46页

作者： Y.Chew Z.G.Zhu F.Weng S.B.Gao F.L.ng B.Y Lee G.j.Bi Singapore Institute of Manufacturing Technology 73 Nanyang Drive637662Singapore School of Mechanical Aerospace Engineering Nanyang Technological University50 N any ang Avenue639798Singapore

Laser aided additive manufacturing(LAAM)was used to fabricate bulk Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial multicomponent alloy using pre-alloyed *** room temperature yield strength(σ_y),ultimate tensile strength(σ_(UTS))and elongation(ε_(UTS))were 645 MPa,917 MPa and 27.0%*** asbuilt sample consisted of equiaxed and dendritic cellular structures formed by elemental *** cellular structures together with oxide particle inclusions were deemed to strengthen the *** other contributing components include dislocation strengthening,friction stress and grain boundary *** highε_(UTS)was attributed to dislocation motion and activation of both twinning and transformation-induced plasticity(TWIP and TRIP).Tensile tests performed at-40℃and-130℃demonstrated superior tensile strength of 1041 MPa and 1267 MPa ***,almost no twinning was observed in the fractured sample tested at-40℃and-130℃.Instead,higher fraction of strain-induced hexagonal close-packed(HCP)εphase transformation of 21.2%were observed for fractured sample tested at-40℃,compared with 6.3%in fractured room temperature sample.

关键词： Multicomponent alloys Laser aided additive manufacturing Additive manufacturing Microstructure Mechanical property

Incorporating geotechnical and geophysical investigations for underground obstruction detection:A case study

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Underground Space 2023年第4期11卷 116-129页

作者： Yaohui Liu Yannick C.H.ng Yunhuo Zhang Ping Yang Taeseo Ku School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 221000China Department of Civil and Environmental Engineering National University of Singapore117576Singapore Geotechnical&Tunnel Division Land Transport Authority Singapore219428Singapore Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Department of Civil and Environmental Engineering Konkuk UniversitySeoul 05029South Korea

Determining the location and boundary of underground obstructions and/or anomalies is a common problem and often a great chal-lenge for tunneling and underground *** this study,geotechnical investigations(penetration tests and borehole drilling/sam-pling)and geophysical investigations(surface wave method and cross-hole seismic method)were conducted with the aim of identifying the location and boundary of rock obstructions in Changi East,*** surface wave method is frequently used in the sites with lateral homogeneity in previous studies,but its application in the sites with rock obstructions is *** experimental results of this study indicate that the surface wave method is also able to determine the upper surface of rock obstructions,but difficult to identify the lateral and bottom boundaries of rock *** improve the precision of detection,the full waveform inversion(FWI)method was used to process the data from the cross-hole seismic *** results indicate that the inversion precision of P-wave is higher than that of *** horizontal and vertical ranges of rock obstructions in the P-wave inversion results are 14–26 m and 7.5–11.0 m respectively,roughly consistent with the results of penetration tests(about 15–25 m)and borehole log(8.85–10.80 m).This result proves that the sequential application of first-arrival time analysis and FWI can effectively delineate the boundary of rock ***,the results of various detection methods were analyzed and compared in this *** the advantages of various methods,we propose a cost-effective and high-precision workflow containing both geotechnical and geophysical investigations.

关键词： FWI Geotechnical and geophysical investigations Cross-hole seismic method Surface wave method Obstruction detection

Development of stable, cold-adapted, temperature-sensitive/conditional lethal chimeric enterovirus A71 and coxsackievirus A16

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Virologica Sinica 2022年第5期37卷 769-773页

作者： Kaw Bing Chua Qimei ng Tao Meng Qiang jia Temasek Life Sciences Laboratory 1 Research LinkNational University of Singapore117604Singapore

Dear Editor,Coxsackievirus A16(CA16)and enterovirus A71(EV-A71)are the main causative agents of hand foot and mouth disease(HFMD)(Alexander et al.,1994).Besides HFMD,EV-A71 infection in young children can lead to a spectrum of other clinical diseases and associated neurological complications and mortality(Melnick jL.,1996).In recent decades,EV-A71 infections have become a major public health concern throughout the world,following the frequent occurrence of epidemics and outbreaks of HFMD associated with neurological complications and high mortality in young children(Ishimaru et al.,1980;Tagaya et al.,1981;Chomnaitree et al.,1982;Samuda et al.,1987;Gilbert et al.,1988;Hayward et al.,1989;Lum et al.,1998;Chang et al.,1998;Liu et al.,2000;Yang et al.,2011;Zeng et al.,2012).

关键词： mortality enterovirus

Modelling the water diversion of a sustainable cover system under humid climates

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journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2429-2440页

作者： Haowen Guo Charles Wang Wai ng Qi Zhang Chuanxiang Qu Liwen Hu Shenzhen Research Institute of Hong Kong University of Science and Technology Shenzhen518057China Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong SAR999077China CCCC Fourth Harbor Engineering Institute Co. LtdGuangzhou510230China

Extreme rainfall significantly threatens the safety of the landfill cover system,especially under humid *** study aims to provide design recommendations for a sustainable landfill cover system consisting of a low-permeability soil layer underlying a two-layer capillary barrier for humid ***,the numerical back-analysis was conducted for verification against a series of flume model ***,a parametric study was performed to investigate the effects of inclination angle,particle size and layer thickness on the lateral diversion length(DL)of the three-layer cover system under the 100-year return period rainfall of humid *** results show that the water lateral DL of the cover system can be greatly enhanced by increasing the inclination angle from 3°to 18°.Moreover,the bottom layer of the cover system with a coarser d10 was more susceptible to the impact of the heavy rainfall,while this can be alleviated by increasing the thickness of the bottom layer.A dimensionless number,defined as the ratio of thickness and d_(10) of the bottom layer,is proposed for designing lateral diversion of the three-layer cover system under humid *** preserve the maximum DL,it is suggested that the proposed dimensionless number should be larger than 95 and 110 for the design of rainfall events with 50-year and 100-year return periods for humid climates,respectively.

关键词： Unsaturated soil Recycling Construction waste Three-layer landfill cover Water infiltration

Three-year field study on grass growth and soil hydrological properties in biochar-amended soil

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journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2764-2774页

作者： Haowen Guo Charles Wang Wai ng junjun Ni Qi Zhang Yuchen Wang Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina School of Transportation Southeast UniversityNanjingChina

Field monitoring was conducted to investigate and quantify the long-term effects of peanut shell biochar on soil-grass interaction over three *** 10 m5 m grassed plots were constructed in completely decomposed granitic *** of them were amended,respectively,with 5%and 10%biochar contents(m^(3)/m^(3))for grass growth,while the third was without biochar *** the threeyear monitoring,plant characteristics,saturated water permeability(k_(s))of grassed soil and soil suction were *** monitored results show that the grass leaf area index(LAI)and root length density(RLD)with biochar amendment were improved by 38%and 200%,*** the grassed plot without biochar,a threshold RLD existed with a value of 1.7 cm/cm^(3),beyond which k_(s) raised *** threshold RLD increased by 52%when biochar content increased from 0%to 10%.This implies that biochar may restrict the increase in k_(s) of grassed soil due to the rise in the threshold *** presence of biochar and grass can retain over 100%higher suction after heavy rainfalls,while 54%lower peak suction under evapotranspiration(ET)compared with the non-amended *** can alleviate the negative effects on hydraulic properties caused by plant growth and reduce ET-induced excessive water loss.A 5%peanut shell biochar content is recommended for the long-term management of vegetated earthen infrastructures.

关键词： Soil-grass interaction Biochar Long-term Water infiltration Soil drying

Single-pilot operations in commercial flight:Effects on neural activity and visual behaviour under abnormalities and emergencies

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Chinese journal of Aeronautics 2024年第8期37卷 277-292页

作者： Qinbiao LI Chun-Hsien CHEN Kam K.H.ng Xin YUAN Cho Yin YIU Human Factors and Ergonomics Laboratory Department of Aeronautical and Aviation EngineeringThe Hong Kong Polytechnic UniversityHong Kong Special Administrative Region 100872China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

With cutting-edge technologies and considering airline human-resource-saving,a single pilot in commercial jets could be technically *** changes in captains’natural behaviours are initially required to comprehend the specific safe human performance envelope for safeguarding single-pilot flight,particularly in high-risk *** paper investigates how captains’performance transforms for fixing emergencies when operating from Dual-Pilot Operations(DPO)to Single-Pilot Operations(SPO)through a physiological-based *** pilots flew an emergency-included flight with/without first officers’*** neural activities and scanning behaviours were recorded using a 32-channel Electroencephalogram(EEG)and glasses-based eye tracker,with the observation and post-experiment questionnaires to evaluate the flight operations and pilots’*** alone,there was a significantly increased cortical activity in h and b waves over the frontal,parietal,and temporal lobes during the more complicated emergencies,and pilots focused less on the primary flight display while spending significantly more time scanning the other *** physiological fluctuating patterns associated with risky operations in SPO were highlighted by cross-correlating multimodal *** experimental-based noteworthy insights may wish to inform commercial SPO measures to lessen the persistent physiological fluctuation,assisting airlines in creating SPO-oriented intelligent flight systems to give captains adequate support for assuring safer air transportation.

关键词： Aviation engineering Single pilot operations Behaviour changes Eye tracker Electroencephalogram