Effect of binder and composition ratio on electrochemical performance of silicon/graphite composite battery electrode

Farooq, U.,Choi, J.H.,Atif Pervez, S.,Yaqub, A.,Kim, D.H.,Lee, Y.J.,Saleem, M.,Doh, C.H. North-Holland 2014 Materials letters Vol.136 No.-

A comparative study was conducted to examine the effect of two different polymer binders and composition ratio of active material on electrochemical performance of silicon-graphite (Si-Gr) composite electrode in rechargeable lithium-ion batteries (LIBs). Polyacrylic acid (PAA) and polyvinylidene fluoride (PVDF) were utilized as binders for composite electrode that was fabricated using Si powder, graphite and super P black (SPB) by varying composition ratios of active material. The electrochemical performance was investigated by galvanostatic charge/discharge tests at room temperature. The results revealed that composite electrode fabricated with PAA binder using maximum contents of Si powder (20wt%) showed high specific capacity around 1000mAhg<SUP>-1</SUP> with excellent capacity retention. The enhanced electrochemical performance can be attributed to high mechanical strength and adhesive capability provided by PAA binder to composite electrode.

Seismic Performance of Masonry Strengthened with Steel Strips

S. H. Farooq,I. Shahid,M. Ilyas 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.7

Strengthening of unreinforced masonry structures to improve their seismic performance is getting attention of civil engineers across the world. In this study, laboratory tests were carried out to investigate the seismic performance of unreinforced burnt clay masonry wall panels strengthened with externally anchored steel strips. Six masonry panels having an aspect ratio of 0.7 were constructed. First masonry panel was unreinforced reference specimen and remaining specimens were strengthened with steel strips using different steel ratios and mesh patterns. Three specimens were strengthened with steel strips on one face and two specimens were strengthened with steel strips on both sides. All the specimens were tested under lateral cyclic loading at constant axial pressure to determine seismic performance. The test results revealed a significant improvement in energy dissipation, ductility and lateral strength of strengthened masonry wall panels. The main contributing factors in performance improvement were 1) amount of steel reinforcement, 2) mesh pattern and 3) single or double side application of steel strips. The proposed steel strips strengthening technique is quite simple and economical which involves external application of steel strips and does not alter the mass significantly. The simplicity, cost effectiveness and efficacy of the technique can help the local designers and engineers to enhance seismic performance of existing masonry structures.

Metal-assisted silicon based negative electrode for Li-ion batteries

Farooq, U.,Yaqub, A.,Choi, J.H.,Pervez, S.A.,Kim, D.H.,Lee, Y.J.,Doh, C.H. North-Holland 2014 Materials letters Vol.126 No.-

Cu-assisted Super-P black (Cu-assisted SPB) composite was synthesized via efficient metal ion-reduction process. The micrometric sized Cu particles embedded on Super-P black (SPB) surface improved the electronic conductivity of electrode and showed quicker kinetic behavior compared to pristine electrode. The electrochemical response of silicon/graphite (Si/Gr) composite electrode manufactured with Cu-assisted SPB and pristine SPB conductive agent was investigated by galvanostatic cycling and electrochemical impedance spectroscopy (EIS). The use of as-prepared Cu-assisted SPB conductive agent remarkably improved performance of Si/Gr electrode in terms of all electrochemical parameters like first coulombic efficiency, cyclic stability and rate capability. The enhancement in electrochemical performance can be attributed to high conductivity provided by Cu particles.

Seismic In-plane Performance of Retrofitted Masonry Walls

S. H. Farooq,A. ElGawady Mohamed,M. Ilyas 대한토목학회 2014 KSCE Journal of Civil Engineering Vol.18 No.1

Retrofitting of masonry to improve its seismic performance is the focus of research community all around the globe. In the present work, a new masonry retrofitting technique using externally anchored steel strips mesh is presented. An extensive experimental programme was carried out to study the effects of proposed technique on masonry lateral strength, ductility, energy dissipation,response and damping factor under lateral cyclic loading. A total of twenty tests were carried out; 1) twelve were lateral cyclic tests,2) four monotonic lateral tests and 3) four pure compression tests. The test results were analysed in five separate groups and this paper presents the analysis of group 3, which deals with the effect of steel retrofitting of un-reinforced masonry wall panels on its seismic performance. Six single leaf panels with aspect ratio of 0.67 were constructed using same type of material and workmanship. It was observed that amount of steel reinforcement and meshing pattern of steel strips had significant effect on seismic performance and failure modes. The simplicity, cost effectiveness and efficacy of this proposed technique could help the local designers and engineers to enhance seismic performance of existing masonry structures.

Study of tin-sulphur-carbon nanocomposites based on electrically exploded tin as anode for sodium battery

Pervez, S.A.,Kim, D.,Lee, S.M.,Doh, C.H.,Lee, S.,Farooq, U.,Saleem, M. Elsevier Sequoia 2016 Journal of Power Sources Vol.315 No.-

An electrochemical study of tin-sulphur-carbon nano-composites, based on electrically exploded tin-carbon nanoparticles as anode for sodium-ion battery (NIB), is carried out in electrolytes with and without fluoroethylene carbonate (FEC). The composites are synthesized through high energy mechanical milling (HEMM) of electrical exploded tin, sulphur nanoparticles and grinded carbon. The final product consists of tin sulfide nanoparticles embedded in amorphous carbon matrix. The results demonstrate an excellent response for the electrode materials in terms of initial discharge capacity (>425 mAhg<SUP>-1</SUP>) and cyclic performance (415 mAhg<SUP>-1</SUP> after 50 cycles). Even more remarkably, at high current densities of 400, 600, and 800 mAg<SUP>-1</SUP>, electrodes still offer specific capacities of about 375, 355, and 315 mAhg<SUP>-1</SUP>, respectively, suggesting good rate capability of the materials. Furthermore, it is observed that the material response is much better when electrolyte has FEC as an additive which helped in the formation of an optimized SEI layer. Such an improved electrochemical performance of the electrode materials highlights their suitability for the recently emerging Na-ion battery technology.

Elimination of servo valve sticking in the steam turbine Electro Hydraulic Control (EHC) system at Dangjin Power using Pall filtration

홍정희(J. H. Hong),김한식(H. S. Kim),칼파루그(Kal Farooq) 유공압건설기계학회 2011 유공압건설기계학회 학술대회논문집 Vol.2011 No.6

Electro Hydraulic Control systems that control the flow of steam into the steam turbines, including such functions as turbine emergency trip, are a critical part of the power generation system. Malfunction of the fine servo valves that control steam control governor system is highly undesirable. These valves, by virtue of their very small operating clearances between the precision machined surfaces are very susceptible to malfunction when fluid suspended contaminant such as fine particles and semi-soft, gel-like material get into the clearance spaces. The contaminants wedge or form deposits on the valve surfaces such as spools, bores and orifices thus reducing the operating clearances, resulting in valve malfunction. In addition to deposits on valves the contaminant deposits on the small, last chance metal secreen filters, orifices, pumps, seals, heat exchanger and reservoir walls-resulting in a range of adverse consequences.

Determining soil quality in urban agricultural regions by soil enzyme-based index

Igalavithana, A. D.,Farooq, M.,Kim, K. H.,Lee, Y. H.,Qayyum, M. F.,Al-Wabel, M. I.,Lee, S. S.,Ok, Y. S. Springer Science + Business Media 2017 Environmental geochemistry and health Vol.39 No.6

Biochar, a potential hydroponic growth substrate, enhances the nutritional status and growth of leafy vegetables

Awad, Y.M.,Lee, S.E.,Ahmed, M.B.M.,Vu, N.T.,Farooq, M.,Kim, I.S.,Kim, H.S.,Vithanage, M.,Usman, A.R.A.,Al-Wabel, M.,Meers, E.,Kwon, E.E.,Ok, Y.S. Butterworth-Heinemann, Ltd 2017 Journal of cleaner production Vol.156 No.-

A hydroponics system developed using a nutrient film technique was used to evaluate the effectiveness of rice husk biochar (RB) alone or in combination with perlite (PL) as substrates for increasing the growth of leafy vegetables compared with that of PL. Seedlings of cabbage, dill, mallow, red lettuce, and tatsoi were grown hydroponically in PL, RB, and PL + RB (1:1 ratio of PL to RB, v/v) substrates for a 30-d under optimal environmental conditions in a greenhouse. Shoot length and fresh/dry masses of cabbage, dill, and red lettuce plants grown in RB substrate were decreased by 49% on average compared to those plants grown in PL substrate. In contrast, PL + RB substrate led to approximately 2-fold increases in shoot length, number of leaves, and fresh/dry masses of leafy vegetable plants compared with those grown in PL substrate. Foliar nutritional composition (Ca, Mg, K, Na, Mn, Fe, and Zn) and nitrogen status (SPAD index) of plants grown in PL + RB and PL substrates suggested the presence of optimal growth conditions for ensuring optimum yield with high quality. In addition, RB substrate contributed to respective increases of 1.2-3.5-fold in leaf K, Mg, Mn, and Zn contents in most vegetable plants compared with those grown in PL substrate. The RB alone or in combination with PL substrates decreased algal growth in the nutrient solutions as confirmed by scanning electron micrographs of microalgae on the RB surface. The results also indicated that use of PL + RB hydroponic substrate could be an alternative and effective technology for the better management of unwanted algal growth in nutrient solutions and high production of leafy vegetables.

간세포암에서 representational difference analysis를 이용한 다양하게 발현되는 유전자의 발견

탁원영 ( W. Y. Tak ),조창민 ( C. M. Cho ),권영오 ( Y. O. Kweon ),김성국 ( S. K. Kim ),최용환 ( Y. H. Choi ),정준모 ( J. M. Chung ),정은영 ( E. J. Chung ),( Mohammad Farooq ),황선영 ( S. Y. Hwang ),김영희 ( Y. H. Kim ),임상욱 ( S. 대한소화기학회 2002 대한소화기학회 춘계학술대회 Vol.2002 No.-

<Introduction> Representational difference analysis (RDA) combined with cDNA arrays is an effective approach to identify differentially expressed genes. To identify differentially expressed genes in human hepatocellular carcinoma (HCC), we used RDA for a

Chlorella vulgaris cultivation with an additive of magnesium-aminoclay

Farooq, W.,Lee, H.U.,Huh, Y.S.,Lee, Y.C. Elsevier Science B.V. Amsterdam 2016 Algal research Vol.17 No.-

<P>In integral microalgal biofuel production consisting of microalgal culturing, harvesting, lipid (oil) extraction, oil-to-biodiesel conversion and biodiesel quality improvement, cultivation to improve lipid (oil) content in microalgal cells without inducement of transformants is a booming field of experimentation and application. In the present study, water-solubilized, transparent and cationic-charged and clustered magnesium-aminoclay (MgAC) was utilized as a co-additive in Chlorella vulgaris cultivation. The MgAC effected both an increase of cell size (from similar to 3.524 mu m to similar to 4.175 mu m size) with low cell density (from 1260 x 10(6) cells/mL to 511 x 10(6) cells/mL) and an increase of total lipid content without microalgal cell transformation according to various MgAC loadings (0, 0.25, 0.50, and 1.0 g/L) at the 2.0% CO2 supply. The cationic-charged MgAC clusters wrapped the microalgal cells to create a stressful microenvironment, increasing the intracellular reactive oxygen species (ROS) content. Therefore, additive-MgAC-based microalgal cultivation is herein suggested in a novel microalgal biofuel production. (C) 2016 Elsevier B.V. All rights reserved.</P>