Experimental investigation of engineered geopolymer composite for structural strengthening against blast loads

The recent increase in blast/bombing incidents all over the world has pushed the development of effective strengthening approaches to enhance the blast resistance of existing civil infrastructures.Engineered geopolymer composite(EGC)is a promising material featured by eco-friendly,fast-setting and strain-hardening characteristics for emergent strengthening and construction.However,the fiber optimization for preparing EGC and its protective effect on structural elements under blast scenarios are uncertain.In this study,laboratory tests were firstly conducted to evaluate the effects of fiber types on the properties of EGC in terms of workability,dry shrinkage,and mechanical properties in compression,tension and flexure.The experimental results showed that EGC containing PE fiber exhibited suitable workability,acceptable dry shrinkage and superior mechanical properties compared with other types of fibers.After that,a series of field tests were carried out to evaluate the effectiveness of EGC retrofitting layer on the enhancement of blast performance of typical elements.The tests include autoclaved aerated concrete(AAC)masonry walls subjected to vented gas explosion,reinforced AAC panels subjected to TNT explosion and plain concrete slabs subjected to contact explosion.It was found that EGC could effectively enhance the blast resistance of structural elements in different scenarios.For AAC masonry walls and panels,with the existence of EGC,the integrity of specimens could be maintained,and their deflections and damage were significantly reduced.For plain concrete slabs,the EGC overlay could reduce the diameter and depth of the crater and spallation of specimens.

驴乳延缓皮肤衰老的研究

使用驴乳溶液处理正常人原代真皮成纤维细胞(HDFn细胞)和人永生化表皮细胞(HaCaT细胞),检测了驴乳对细胞活性、细胞增殖、损伤修复的影响。研究了驴乳溶液处理HDFn细胞后细胞外基质(胶原蛋白、基质金属蛋白酶)含量的影响。质量浓度为0.63~10 mg/mL驴乳作用于HDFn细胞和HaCaT细胞,细胞安全无毒性。通过BrdU法检测不同质量浓度的驴乳对HDFn细胞和HaCaT细胞的增殖能力,5、10 mg/mL驴乳具有显著的促进细胞增殖的作用(p<0.01)。与阴性对照相比,5、10 mg/mL驴乳可促进HDFn细胞中ColⅠ合成(p<0.01),抑制MMP-1分泌。5、10 mg/mL驴乳作用HDFn细胞24 h后,与阴性对照相比,细胞愈合率显著提高(p<0.01)。驴乳可促进细胞增殖、增加胶原蛋白含量、抑制MMP-1分泌、促进损伤修复,发挥延缓皮肤衰老的作用,为其在护肤品中的应用提供科学依据。

Synthesis of Ethyl Methyl Carbonate Catalyzed by Immobilized Carboxylic Functionalized Ionic Liquids via Transesterification Reaction

The carboxylic functionalized ionic liquid was immobilized on the molecular sieve(MCM-22)and then applied in the catalytic synthe-sis of ethyl methyl carbonate(EMC)via transesterification of dimethyl carbonate(DMC)with ethanol.Combined characterization results of FT-IR,XRD and TG suggest that the ILs had been immobilized on molecular sieve MCM-22.The influences of reaction temperature,time,and the mass ratio of MCM-22-CPTES-MIL/Ca O have also been investigated in detail.The catalytic tests demonstrated that MCM-22-CPTES-MIL/Ca O could catalyze the transesterification of DMC and ethanol with high efficiency,superior to those results of the heterogeneous catalysts reported previously.

Analysis of Road Embankment Slope Stability

The stability of earthworks (cuttings, embankments, dikes) and natural slopes is a?problem that is of concern to geotechnicians, both practitioners and researchers. The disorders generated by breaking the slopes are usually spectacular, often destructive and sometimes murderers. Many methods of calculating stability have been proposed. These are differentiated?by the assumptions accepted by their authors (methods of calculation in equilibrium limit, methods of calculation at break, deformation calculation methods) and the ease of their implementation (calculations using charts, automatic calculations using software), but they all agree to define an overall factor of safety according to which the stability?of?the studied slope is considered to be insured or compromised, or by safety factor spartial effects on the one hand, applied stresses and, on the other hand, the mechanical properties soil. Various embankment strengthening techniques have been developed. They are differentiated by the process of their realization, their cost and their durability. The main objective of this study is to present the problems of both natural and artificial slope stability on construction projects. In this regard, special emphasis?is given to the sensitivity of the calculation model input parameters (soil, load),?which should contribute to raising awareness about this issue, as a prerequisite to make the right decisions and optimal technical solutions in this area.

Study on Evaluation Method of Teaching Quality Based on Cloud Model and D-S Theory

The Evaluation of teaching quality is a complicated project. It’s a typical problem of uncertainty. A design scheme of teaching quality evaluation method based on cloud model and D-S theory is proposed with the school teaching evaluation index. With the experiences and knowledge of experts, evaluation index was described by cloud model and judgment matrix of AHP was revised by D-S theory. The weight of evaluation indexes was determined reasonably and objectively. Applied in the actual environment, the method can make an accurate and efficient evaluation with a certain practical value.

Urgent Need of Continuing Medical Education:The Key for Patient Awareness of Labor Epidural Analgesia-A Survey of Chinese Perinatal Care Providers

Objective:This survey was designed to understand the misconceptions about labor epidurals.Methods:This voluntary and anonymous online survey on wenjuan.com was conducted from September 1st,2015 to January 1st,2016 via mainly WeChat groups dedicated to perinatal healthcare providers in China.The questionnaire included items inquiring the knowledge and opinions about labor epidural analgesia related to maternal complications,baby safety,and effect on laboring.Incomplete surveys were excluded from the data analysis.The data was presented as percentages and a Chi-square test or Fisher's exact test,as appreciate,was used to quantitatively compare the results.Results:A total of 1412 respondents completed surveys with 42.9%(606/1412)of them being anesthesiologists,35.1%(495/1412)being obstetricians,11.8%(167/1412)being midwives,3.7%(52/1412)being labor and delivery nurses,and 6.5%(92/1412)being hospital administrators and unspecified.The study revealed a lack of knowledge in labor pain control.Although 82.4%(1164/1412)of respondents were familiar with labor epidural analgesia,8.9%(126/1412)did not know how it works,and 1.1%(15/1412)never heard it in a multiple-choice question.The three main groups(anesthesiologists,obstetricians,and midwives/labor and delivery nurses)were chosen for comparisons.Opinions among these three groups concerning five questions in the three main concerns were evaluated using a statistical significance of P<0.05.Conclusion:The results in our survey indicated an urgent need of continuing medical education to multidisciplinary specialties to improve evidence-based medical practices as these misconceptions have existed for over 10 years in the medical professionals.Lack of public awareness fueled by misconceptions related to labor epidural analgesia may be associated with a lack of professional knowledge.Correct knowledge in professionals needs to be disseminated to the public in order to dispel possible misconceptions and rumors about labor epidural analgesia.This would not only enhance patient understanding of their care but also improve maternal,fetal,and neonatal outcomes.