Synthesis and Characterization of Agglomerated Coarse Al Powders Comprising Nanoparticles by Low Energy Ball Milling Process

Eom, Nusia,Bhuiyan, Mahedi Hasan,Kim, Taek-Soo,Hong, Soon-Jik The Japan Institute of Metals 2011 MATERIALS TRANSACTIONS Vol.52 No.8

<P>Agglomerated coarse Al powders consisting of nanoparticles were synthesized by low energy ball milling process, and subsequently their structures were characterized in terms of agglomeration size, shape, and porosity depending on various milling time, ball size, and ball to powder weight ratio in order to optimize the process parameters. A higher milling time caused a decrease in the agglomeration size and their shape tends to become spherical while reducing the pore sizes. The agglomeration size was also reduced as the ball to powder weight ratio increased and the ball size decreased. The partial cold welding of the nanoparticles at lower milling time and fully cold welding of the nanoparticles at higher milling time were correspondingly responsible to produce larger and smaller agglomerations, respectively.</P>

Distributional Pattern of Tree Species in Response to Soil Variables in a Semi Natural Tropical Forest of Bangladesh

Ara, Saida Hossain,Limon, Mahedi Hasan,Kibria, Mohammad Golam Institute of Forest Science 2021 Journal of Forest Science Vol.37 No.1

A plant community is a group of populations that coexist in space and interact directly or indirectly with the environment. In this paper, we determined the pattern of tree species composition in response to soil variables in Khadimnagar National Park (KNP), which is one of the least studied tropical forests in Bangladesh. Soil and vegetation data were collected from 71 sample plots. Canonical Correspondence Analysis (CCA) with associated Monte Carlo permutation tests (499 permutations) was carried out to determine the most significant soil variable and to explore the relationship between tree species distribution and soil variables. Soil pH and clay content (pH with p<0.01 and Clay content with p<0.05) were the most significant variables that influence the overall tree species distribution in KNP. Soil pH is related to the distribution and abundance of Syzygium grande and Magnolia champaca, which were mostly found and dominant species in KNP. Some species were correlated with clay content such as Artocarpus chaplasha and Cassia siamea. These observations suggest that both the physico-chemical properties of soil play a major role in shaping the tree distribution in KNP. Hence, these soil properties should take into account for any tree conservation strategy in this forest.

Pyrolytic preparation of gold nanoparticle-coated taro carbon and its application for the selective detection of dopamine

Ahammad, A. J. Saleh,Hasan, Md. Mahedi,Islam, Tamanna,Al-Shehri, Mohammod Oudah,Anju, Anjuman Nesa,Alam, Md. Kawsar,Kim, Jong-Pil,Qasem, Mohammed Ameen Ahmed,Aziz, Md. Abdul The Royal Society of Chemistry 2018 NEW JOURNAL OF CHEMISTRY Vol.42 No.6

<P>A highly selective and sensitive electrochemical method was developed for the detection of dopamine (DA), based on a gold nanoparticle (AuNP)-coated taro carbon (TC)-modified glassy carbon electrode (AuNP-TC/GCE). This novel AuNP-TC material was simply prepared by carrying out a pyrolysis of a composite material obtained by treatment of an acid-treated taro stem powder with HAuCl4. Transmission electron microscopy (TEM), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were employed to characterize the AuNP-TC material. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to characterize the modified electrode. The modified GCE exhibited a well-defined current response only toward the electrochemical oxidation of DA in a mixture solution of ascorbic acid (AA), DA, and uric acid (UA). This designed electrochemical sensor showed a linear response in the concentration range of 0.5 μM to 250 μM DA and a sensing limit (S/N = 3) of 0.25 μM was found. The sensor was also able to successfully detect DA in a dopamine hydrochloride injection (DAI). Moreover, the sensor exhibited excellent stability and reproducibility.</P>

Reduced Graphene Oxide Screen-Printed FTO as Highly Sensitive Electrodes for Simultaneous Determination of Dopamine and Uric Acid

Ahammad, A. J. Saleh,Islam, Tamanna,Hasan, Md. Mahedi,Mozumder, M. N. Islam,Karim, Rejwana,Odhikari, Noyon,Pal, Poly Rani,Sarker, Subrata,Kim, Dong Min The Electrochemical Society 2018 Journal of the Electrochemical Society Vol.165 No.5

<P>A novel electrochemical sensor was fabricated by simply screen printing reduced graphene oxide (rGO) paste on F-doped tin oxide (FTO) (rGO-SP-FTO) followed by sintering at 450 degrees C in Argon and employed for detecting dopamine (DA) and uric acid (UA) simultaneously. The rGO film was characterized by using Raman spectroscopy, field emission scanning electron microscope (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The surface sensing features of rGO-SP-FTO were studied with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The rGO-SP-FTO electrode exhibited foremost sensitivity in simultaneous detection of DA and UA without any interference from ascorbic acid (AA). The rGO-SP-FTO electrode showed a good linear response in the range of 0.5-50.0 mu M and 5.0-300 mu M with detection limits (S/N = 3) of 0.07 mu M and 0.39 mu M for DA and UA, respectively. The interactions between screen printed rGO with FTO electrode and their influence on how rGO-SP-FTO electrode interacted with UA, DA, and AA were analyzed from experimental observations. The rGO-SP-FTO electrode was able to detect DA in dopamine hydrochloride injection (DAI) and UA in urine sample effectively. Moreover, the designed electrochemical sensor exhibited excellent stability and reproducibility. (C) 2018 The Electrochemical Society.</P>

Activated jute carbon paste screen-printed FTO electrodes for nonenzymatic amperometric determination of nitrite

Ahammad, A.J. Saleh,Pal, Poly Rani,Shah, Syed Shaheen,Islam, Tamanna,Mahedi Hasan, Md.,Qasem, Mohammed Ameen Ahmed,Odhikari, Noyon,Sarker, Subrata,Kim, Dong Min,Abdul Aziz, Md. Elsevier 2019 Journal of Electroanalytical Chemistry Vol.832 No.-

<P><B>Abstract</B></P> <P>Aiming at constructing a new nonenzymatic electrochemical nitrite sensor, we have prepared a screen-printed fluorine-doped tin oxide (FTO) electrode with activated jute carbon paste (AJCP) (AJCP-SP-FTO) synthesized from jute (<I>Corchorus</I> genus) sticks by using ZnCl<SUB>2</SUB> as activating agent and subsequent carbonizing at 850°C. Surface morphology, textural properties, chemical composition and nature of pores of AJC were studied by FE-SEM, XRD, EDS, Raman spectroscopy and BET analysis. The surface area of the AJC was found to be 1452.4m<SUP>2</SUP>/g with an average pore diameter of 2.6nm obtained from a BJH pore-size distribution curve. Electron transfer capacity at the interface of the AJCP material screen-printed FTO was studied by cyclic voltammetry (CV) and EIS techniques. The AJCP-SP-FTO sensor was used for amperometric detection of nitrite. The limit of detection (LOD) for nitrite oxidation was found to be 437nM for the proposed sensor. The sensitivity of AJCP-SP-FTO toward nitrite was 863.71μAmM<SUP>−1</SUP> cm<SUP>−2</SUP>. From the analysis of electrochemical data, the effective surface area of the AJCP-SP-FTO was 0.12cm<SUP>2</SUP>. We proposed a mechanism for sensitive detection of nitrite based on analysis of experimental findings of spectroscopic and electroanalytical techniques. We further utilized the proposed sensor for analyzing nitrite in tap water. The AJCP-SP-FTO electrode showed good reproducibility and stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Activated jute carbon (AJC) material was prepared by using ZnCl<SUB>2</SUB> as activating agent. </LI> <LI> Surface morphology, textural properties, chemical composition and nature of pores of AJC were studied. </LI> <LI> A novel AJC paste screen printed FTO electrode was constructed for nonenzymatic electrochemical determination of nitrite. </LI> <LI> The detection limit and sensitivity of nitrite were calculated to be 437 nM and 863.71 μA μM<SUP>-1</SUP> cm<SUP>-2</SUP>, respectively. </LI> <LI> A mechanism for detection of nitrite was proposed based on analysis of spectroscopic and electroanalytical techniques. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>