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| 1 | A standard formulation for the installation of suction caissons in sand显示文摘Suction assisted installation of caisson foundations in sand relies on the developed seepage around the caisson wall.Seepage is known to produce soil loosening inside the caisson cavity and an overall reduction in soil resistance to caisson penetration.On the other hand,suction must be controlled so that no excessive piping is induced within the sand volume trapped inside the caisson cavity.When it extends over the full embedded length of the caisson wall,piping may lead to the formation of piping channels,which may compromise the established seal between caisson and soil and ultimately cause the installation process to stop.A safe installation process requires a proper design procedure to ensure that a safe suction can be predicted prior to installation.The present paper provides a framework where analytical expressions are obtained for the required suction magnitude,and for the critical suction that causes piping to initiate at the caisson tip.These analytical expressions are derived for a normalized caisson geometry,based on compiled results obtained from finite element analysis of seepage around a caisson wall,at various installation depths.The developed analytical formulation applies independently of caisson dimensions such as diameter,height and wall thickness.Critical suction for piping condition is also obtained under analytical form as a function of normalized penetration depth.The developed formulation can also be easily incorporated into design procedures or used in design codes without a need for a preliminary seepage analysis to be undertaken.The proposed suction predictions for the whole process of caisson installation in sand are validated against field trials reported in the literature. | Ayed Eid Alluqmani Muhammad Tayyab Naqash Ouahid Harireche | 2019 | Journal of Ocean Engineering and Science2019,4,4: | 0 |
| 2 | 波流混合下铰接式波浪能装置工作特性研究显示文摘波流混合后的波流场对波浪能装置的浮体运动和波能俘获具有不可忽视的影响。本文以多浮体铰接式波浪能装置为研究对象,建立三维数值波流水槽对装置的工作性能进行数值仿真研究。结果表明,流对装置浮体的纵摇周期、幅值及运动等影响显著。随着流速的增加,浮体运动周期减小,浮体纵摇和PTO转换功率曲线最大值均出现在浮体共振处。但当浮体固有纵摇周期小于波浪周期时,曲线呈现双峰特征,次高峰值出现在逆向流工况的纵摇幅值最大处。 | 李彪 Muhammad Naqash Tahir 隋芳芳 王军 董宇豪 | 2022 | 舰船科学技术2022,44,23: | 0 |
| 3 | A Potential Approach to Enhance the Seebeck Coefficient of UHMWPE by Using the Graphene Oxide显示文摘Thermoelectric materials have been a competent source for the production of energy in the present decade.The most important and potential parameter required for the material to have better thermoelectric characteristics is the Seebeck coefficient.In this work,ultra high molecular weight polyethylene(UHMWPE)and graphene oxide(GO)nanocomposites were prepared by mechanical mixing by containing 10000ppm,50000ppm,70000ppm,100000ppm,150000ppm,and 200000ppm loadings of graphene oxide.Due to the intrinsic insulating nature of UHMWPE,the value of Seebeck for pristine UHMWPE and its nanocomposites with 10000ppm&50000ppm of GO concentration was too low to be detected.However,the Seebeck coefficient for composites with 70000ppm,100000ppm,150000ppm,and 200000ppm loadings of GO was found to be 180,206,230,and 235μV/K,respectively.These higher values of Seebeck coefficients were attributed to the superior thermal insulating nature of UHMWPE and the conductive network induced by the GO within the UHMWPE insulating matrix.Although,the values of the figure of merit and power factor were negligibly small due to the lower concentration of charge carriers in UHMWPE/GO nanocomposites but still reported,results are extremely hopeful for considering the composite as the potential candidate for thermoelectric applications. | Aqsa Irfan Malik Naqash Mehmood Malik Sajjad Mehmood Arif Aziz Mansoor Ahmad Baluch Muhammad Rizwan Tariq Yasin | 2020 | Non-Metallic Material Science2020,2,2: | 0 |
| 4 | Tocilizumab in severe COVID-19-A randomized,double-blind,placebo-controlled trial显示文摘Background:The therapeutic effectiveness of interleukin-6 receptor inhibitor in critically ill hospitalized patients with coronavirus disease 2019(COVID-19)is uncertain.Methods:To evaluate the efficacy and safety of the outcome as recovery or death of tocilizumab for severe acute respiratory syndrome-coronavirus-2(SARS-CoV-2)infection,we conducted a randomized,double-blinded,placebo-controlled phase 2 trial in critically ill COVID-19 adult patients.The patients were randomly assigned in a 4:1 ratio to receive standard medical treatment plus the recommended dose of either tocilizumab or the placebo drug.Randomization was stratified.The primary outcome was the recovery or death after administration of tocilizumab or a placebo drug.The secondary outcomes were clinical recovery or worsening of the patients’symptoms and inflammatory markers and discharge from the hospital.Results:Of 190 patients included in this study,152 received tocilizumab,and 38 received a placebo.The duration of hospital stay of the interventional group was 12.9±9.2,while the placebo group had a more extended hospital stay(15.6±8.8).The mortality ratio for the primary outcome,ie,mortality or recovery in the tocilizumab group was 17.8%;p=0.58 by log-rank test).The mortality ratio in the placebo group was 76.3%;p=0.32 by log-rank test).The inflammatory markers in the tocilizumab group significantly declined by day 16 compared to the placebo group.Conclusions:The use of tocilizumab was associated with decreased mortality,earlier improvement of inflamma-tory markers,and reduced hospital stay in patients with severe COVID-19. | Muhammad Irfan Malik Sardar Al Fareed Zafar Fabiha Qayyum Muna Malik Muhammad Sohaib Asghar Muhammad Junaid Tahir Ammarah Arshad Fatima Khalil Hafiza Shafia Naz Mudassar Aslam Jodat Saleem Abdul Aziz Mustafa Usman Azhar Muhammad Naqash Zohaib Yousaf | 2022 | Infectious Medicine2022,1,2: | 0 |