http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of Cracking on Corrosion of Steel in Concrete
Faiz Uddin Ahmed Shaikh 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.1
It is generally recognized that cracks provide easy access to ingress of chlorides in concrete and hence, the initiation of corrosion of steel in cracked concrete occurs at early stage. However, wide variety of results on the effect of crack widths on corrosion of steel in concrete are reported in many studies. Apart from crack width, the crack depths, cracking frequency and healing of cracks also influence the corrosion of steel in concrete. This paper presents a comprehensive review and summarised the results on the effect of cracking on corrosion of steel in concrete. The effect of crack widths on the diffusion of chlorides ions and carbon-dioxide is also discussed in this paper. Among all available results, a correlation between the corrosion current and the crack widths up to 0.3 mm can be established, however, no distinct trends are observed beyond that crack width. Conflicting results on the effect of crack widths on chloride ion diffusion are also reported. The longitudinal crack causes more severe corrosion of steel in concrete than transverse cracks of same width. Cracked concrete containing supplementary cementitious materials exhibited superior corrosion resistance than cracked ordinary Portland cement concrete of same width of transverse as well as longitudinal cracks. The same is also true in the case of lower water–binder ratios of cracked concrete. The increase in crack depth increased the chloride diffusion; however, the corrosion test shows an opposite trend. Conflicting results on the effect of crack frequency on corrosion of steel are also reported.
Ahmed, Faiz,Rahman, Md Mahbubur,Chandra Sutradhar, Sabuj,Lopa, Nasrin Siraj,Ryu, Taewook,Yoon, Soojin,Choi, Inhwan,Lee, Seungchan,Kim, Whangi Elsevier 2019 ELECTROCHIMICA ACTA Vol.298 No.-
<P><B>Abstract</B></P> <P>Novel electrolytes with wide electrochemical potential window and high thermal stability have great potential for aqueous rechargeable lithium-ion batteries (ARLBs). Herein, we report the synthesis of two ionic salts of lithium sulfonylbis(fluorosulfonyl)imide (LiSFSI) and lithium carbonylbis(fluorosulfonyl)imide (LiCFSI) with divalent Li<SUP>+</SUP> for ARLBs. These ionic compounds are the derivatives of monovalent lithium bis(fluorosulfonyl)imide (LiFSI). The LiSFSI and LiCFSI exhibit the kinetic electrochemical stability window of ca. 3.78 and 3.52 V, respectively, which can be further expanded due to the formation of a stable solid electrolyte interface (SEI) layer. While LiFSI exhibits the kinetic electrochemical stability window of ca. 2.22 V without the formation of an SEI layer. Full ARLBs based on LiSFSI and LiCFSI electrolytes with a LiCoO<SUB>2</SUB> cathode and graphite anode can deliver the specific discharge capacity of ca. 113.50 and 95.0 mAh/g, respectively, at 0.1C rate. Whereas, it is ca. 52.53 mAh/g for LiFSI at 0.1C rate. The capacity retention for LiSFSI, LiCFSI, and LiFSI based ARLBs are ca. 97.3, 89.6, and 67.8%, respectively, after 500 cycles. Furthermore, both LiSFSI and LiCFSI reveal much higher thermal stability compared to LiFSI. Thus, the derivatization of conventional ionic compounds is an effective strategy to enhance the battery performance and its lifetime.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel divalent organo-lithium electrolytes (LiSFSI and LiCFSI) were prepared and characterized. </LI> <LI> The electrolytes exhibited enhanced thermal and electrochemical stability. </LI> <LI> Both LiSFSI and LiCFSI have formed a stable and dense SEI layer. </LI> <LI> A maximum specific discharge capacity of 113.50 mAh/g was attained with LiSFSI in ARLBs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Ahmed Gaffer Hegazi,Fayez Mohammed Al Guthami,Ahmed Faiz Al Gethami,Hassan Ali El Fadaly 대한약침학회 2017 Journal of pharmacopuncture Vol.20 No.2
Objectives: The Toxoplasma gondii (T. gondii) is an intracellular opportunistic protozoan parasite that infects approximately one-third of the human population worldwide. Honey has long been used for treatment of many diseases in folk medicine. Honey has exhibited significant anthelmintic, nematicidal and anti-protozoal activities. This study was conducted to investigate the immunological patterns in rats infected with T. gondii who were treated orally with supplemented 15% Capparis spinosa honey (Saudi Arabia) for a period of 28 days. Methods: Immunoglobulin M, immunoglobulin G, and cytokines were detected by using enzyme-linked immunosorbent assays (ELISAs). In addition, the mortality and the morbidity rates were assessed. Results: Oral administration of Capparis spinosa honey as a natural food additive was experimentally shown to increase the antibody titer; furthermore, compared with the rats in the control group, the levels of the sera cytokines (IFN-γ, IL-1 and IL-6) were consistently higher at day 7 post-infection in the infected rats treated with oral supplements of Capparis spinosa honey. Conclusion: Orally administered supplements of Capparis spinosa honey increased both the antibody titer and the cytokines (IFN-γ, IL-1 and IL-6) levels in rats infected with T. gondii.
Faiz Ahmed,Mohammad Mahbubur Rahman,Sabuj Chandra Sutradhar,Nasrin Siraj Lopa,류태욱,윤수진,최인환,김재웅,Yongcheng Jin,김환기 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.78 No.-
This research demonstrates the synthesis of an imidazolium functionalized imide based electrolyte salt,lithium (fluorosulfonyl)((3-(1-methyl-1H-imidazol-3-ium-3-yl)propyl)sulfonyl)imide) bis(trifluorosulfonyl)imide (LiFSMIPTFSI) for the development of lithium-ion battery (LIB). The LiFSMIPTFSI electrolytewith a mix-solvent of ethylene carbonate (EC) and dimethyl sulfoxide (DMSO) (75:25 v/v) shows highelectrochemical oxidative stability (up to 5.3 V vs. Li/Li+), good Li+ conductivity (ca. 6.10 mS/cm at 30 C)and transference number (ca. 0.55), and low viscosity, which concurrently provide a specific capacity ofca. 141 mAhg 1 at 0.1 C with a full LIB structure of LiFePO4/LiFSMIPTFSI/graphite. The electrochemicalperformance of this electrolyte is enhancing additionally by adding conventional imide salts (lithium bis(fluoro-sulfonyl)imide (LiFSI) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI)) (20% each) asadditives with the specific capacity of ca. 160 and 150 mAhg 1, respectively, at 0.1 C. This is mainly due tothe additional enhancement of Li+ conductivity and transference number of the LiFSMIPTFSI electrolyteinduce by the additives. The LiFSMIPTFSI electrolyte with LiFSI additive based LIB shows the maximumcapacity retention of ca. 95.50% among the electrolytes after 500 charge-discharge cycles, along with highcoulombic efficiency (98.50%).
Ahmed, Faiz,Sutradhar, Sabuj Chandra,Ryu, Taewook,Jang, Hohyoun,Choi, Kunyoung,Yang, Hanmo,Yoon, Sujin,Rahman, Md. Mahbubur,Kim, Whangi Pergamon Press 2018 International journal of hydrogen energy Vol.43 No.10
<P><B>Abstract</B></P> <P>Branched and linear sulfonated poly(phenylene)s (BSPs and LSPs, respectively) polymer electrolyte membranes (PEMs) containing benzophenone moiety were successfully synthesized and the performance of the LSPs and BSPs were compared in conjunction with Nafion 211<SUP>®</SUP>. The LSPs and BSPs were synthesized by the CC coupling polymerization reaction between 1,4-dichloro-2,5-dibenzoylbenzene (PBP) and 1,4-dichloro-2-benzoylbenzene, and from PBP, 1,4-dichloro-2-benzoylbenzene, and 1,3,5-trichlorobenzene (branching agent), respectively. The degree of sulfonation in both LSPs and BSPs were controlled by varying the concentrations of chlorosulfonic acid and the structures of the resultant PEMs were confirmed by <SUP>1</SUP>H-NMR spectroscopy. The optimal LSP (LSP-2) and BSP (BSP-2) PEMs showed excellent chemical stability due to the absence of ether linkages in the polymer backbone, while the BSP-2 exhibited better proton conductivity (94.6 mS/cm under 90% relative humidity at 80 °C), water resistivity, and lower dimensional changes compared to the LSP-2, which is comparable to Nafion 211<SUP>®</SUP>. The maximum power density for BSP-2 and LSP-2 were 0.60 and 0.49 W/cm<SUP>2</SUP>, respectively, while it was 0.62 W/cm<SUP>2</SUP> for Nafion 211<SUP>®</SUP>. Membrane properties were studied with regard to ion exchange capacity, dimensional stability, proton conductivity, thermogravimetric analysis, and water uptake. The surface morphology of membranes was also analyzed by atomic force microscope.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Branched and linear sulfonated (BSP and LSP, respectively) polymer electrolyte membranes (PEMs) were synthesized. </LI> <LI> The properties and the performance of the synthesized PEMs were compared in conjunction with Nafion 211<SUP>®</SUP>. </LI> <LI> The optimal BSP showed better proton conductivity, physical, and chemical stability than LSPs. </LI> <LI> The power density in fuel cells based on optimized BSP, LSP, and Nafion 211<SUP>®</SUP> were 0.60, 0.49 and 0.62 W/cm<SUP>2</SUP>, respectively. </LI> </UL> </P>
Ahmed, Faiz,Rahman, Md. Mahbubur,Sutradhar, Sabuj Chandra,Lopa, Nasrin Siraj,Ryu, Taewook,Yoon, Sujin,Choi, Inhwan,Lee, Yonghoon,Kim, Whangi Elsevier 2019 ELECTROCHIMICA ACTA Vol.302 No.-
<P><B>Abstract</B></P> <P>Herein, we report the synthesis of a novel imidazolium-based ionic salt, lithium (fluorosulfonyl) ((3-(1-methyl-1H-imidazol-3-ium-3-yl)propyl)sulfonyl) bis(fluorosulfonyl)imide (LiFSMIPFSI) as an electrolyte for the application in lithium-ion battery (LIB). The as-synthesized LiFSMIPFSI exhibited high purity and yield, which was characterized by various spectroscopic techniques. The LiFSMIPFSI electrolyte with a mixed solvent of ethylene carbonate (EC) and dimethyl sulfoxide (DMSO) (75:25 v/v) showed a wide electrochemical stability (ca. 4.5 V <I>vs.</I> Li/Li<SUP>+</SUP>) and high thermal stability (300 °C), good Li<SUP>+</SUP> conductivity (ca. 8.02 mS/cm at 30 °C), and low intrinsic viscosity, which concurrently delivered a specific discharge capacity of ca. 125 mAhg<SUP>−1</SUP> at 0.1 C with the full LIB configuration of LiFePO<SUB>4</SUB>/electrolytes/graphite. The performance of this LiFSMIPFSI electrolyte was enhanced further by the addition of conventional lithium bis(fluoro-sulfonyl)imide (LiFSI) and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) ionic salts (20% each) as additives with the specific discharge capacity of ca. 147 and 139 mAhg<SUP>−1</SUP>, respectively, at 0.1 C. This is mainly due to the additional enhancement of Li<SUP>+</SUP> conductivity and its concentrations in the electrolytes induced by the additives. The LiFSMIPFSI electrolyte with LiFSI additive based LIB showed the highest cycling stability (capacity retention ca. 97%) among the electrolytes after 500 charge-discharge cycles. Thus, the present work contributes to the development of new ionic salts and its effects upon the addition of additives on LIB performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Imidazolium-based ionic salt (LiFSMIPFSI) was prepared as an electrolyte for LIBs. </LI> <LI> LiFSMIPFSI electrolyte showed good ionic conductivity and LIB performance. </LI> <LI> LiFSI and LiTFSI were added as additives to enhance the performance of LiFSMIPFSI. </LI> <LI> LiFSMIPFSI with LiFSI additive delivered a maximum capacity of 147 mAhg<SUP>−1</SUP>. </LI> <LI> The electrolyte without/with additives showed good capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>