Sensitive and selective m-tolyl hydrazine chemical sensor development based on CdO nanomaterial decorated multi-walled carbon nanotubes

Mohammed M. Rahman,M.M. Alam,Khalid A. Alamry 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-

In this approach, the wet-chemical (co-precipitation) technique was used to prepare the cadmium oxide(CdO) nanoparticles (NPs) decorated with multi-walled carbon nanotubes (CNT) at low temperature. Thepowder XDR, UV–vis, TEM, XPS, and FTIR spectroscopy were used for detail characterization of thesynthesized CdO/CNT nanocomposite (NCs). A thin layer of CdO/CNT NCs was deposited onto a glassycarbon electrode (GCE) with conducting coating binder to obtain a chemical sensor which wassubsequently used to detect m-tolyl hydrazine hydrochloride (m-THyd) in buffer medium byelectrochemical approach for environmental safety. The proposed m-THyd chemical sensor exhibitedlong-term stability, good selectivity, broad linear dynamic range, lower detection limit, and enhancedelectrochemical response. The calibration curve of the current vs concentration of m-THyd was found tobe linear (r2 = 0.9903) over the linear dynamic range (LDR) of 0.01 nM to 0.1 mM. The sensitivity(25.7911 mA mM cm 2) of chemical sensor was calculated from the slope of calibration curve and surfacearea of GCE (0.0316 cm2) and the detection limit (4.0 0.2 pM) was estimated from the signal to noiseratio at 3. These preliminary results suggest that the newly developed CdO/CNT NCs nanocompositecould be promising electrochemical sensors for the detection of hazardous toxins to clean theenvironment in broad scales.

Acoustic Species Identification of Korean Myotis Bats (Chiroptera: Vespertilionidae)

Kwang Bae Yoon,M. Mafizur Rahman,Yung Chul Park 강원대학교 산림과학연구소 2016 Journal of Forest Science Vol.32 No.1

We investigated structure and intensity of 267 echolocation calls that were collected from the five Korean Myotis species (M. nettereri, M. petax, M. ikonnikovi, M. macrodactylus and M. formosus). All the Myotis species produced typical FM call pattern with similar echolocation call shapes and outer shapes, producing steep, downward frequency-modulated calls. A pulse has two harmonies, which consist of the first harmony with wider bandwidth and the second harmony with narrower bandwidth. The PF of the first harmony is higher than that of the second harmony. The typical FM call structure, with two harmonies and wide bandwidth, might be highly related to fast flying and wide screening in the dense forests. In classification of the echolocation calls by DFA, most of calls from the five species could be well correctly classified. All calls of M. nettereri (100% of 17 calls), M. formosus (95.5% of 22 calls) and M. ikonnikovi (85.7% of 70 calls) could be well discriminated from those of the other species, whereas calls of M. petax and M. macrodactylus could be discriminated by 70.4% of 98 calls and 76.7% of 60 calls, respectively. Our results indicate that the five Korean Myotis species can be well identified by the echolocation calls with high correct classification by DFA.

Acoustic Species Identification of Korean Myotis Bats (Chiroptera: Vespertilionidae)

Yoon, Kwang Bae,Rahman, M. Mafizur,Park, Yung Chul Institute of Forest Science 2016 Journal of Forest Science Vol.32 No.1

We investigated structure and intensity of 267 echolocation calls that were collected from the five Korean Myotis species (M. nettereri, M. petax, M. ikonnikovi, M. macrodactylus and M. formosus). All the Myotis species produced typical FM call pattern with similar echolocation call shapes and outer shapes, producing steep, downward frequency-modulated calls. A pulse has two harmonies, which consist of the first harmony with wider bandwidth and the second harmony with narrower bandwidth. The PF of the first harmony is higher than that of the second harmony. The typical FM call structure, with two harmonies and wide bandwidth, might be highly related to fast flying and wide screening in the dense forests. In classification of the echolocation calls by DFA, most of calls from the five species could be well correctly classified. All calls of M. nettereri (100% of 17 calls), M. formosus (95.5% of 22 calls) and M. ikonnikovi (85.7% of 70 calls) could be well discriminated from those of the other species, whereas calls of M. petax and M. macrodactylus could be discriminated by 70.4% of 98 calls and 76.7% of 60 calls, respectively. Our results indicate that the five Korean Myotis species can be well identified by the echolocation calls with high correct classification by DFA.

Fabrication of Bismuth Vanadate (BiVO4)Nanoparticles by a Facile Route

M. F. Rahman,M. S. Haque,M. Hasan,M. A. Hakim 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.6

Monoclinic bismuth vanadate (m-BiVO4 ) has attracted many researchers as an advanced photocatalyst for hydrogen production via water splitting and degradation of organic contaminants. In this study, pure m-BiVO4 nanoparticles were fabricated by an easy reproducible solid state route at different temperatures (500 °C, 550 °C, 600 °C, 650 °C and 700 °C) for 2 h. The synthesized materials were characterized by X-ray Diff ractometer where all the diff raction patterns reveal characteristic peaks corresponding to m-BiVO 4 with space group C2/c. Obtained m-BiVO4 particles have the lattice parameters: a = 7.2477 Å, b = 11.6970 Å, c = 5.0900 Å and the volume of the unit cell is 309.23 (106 pm 3 ). Fourier Transform Infrared spectroscopy exhibits formation of Bi–O bond in the prepared nano powders. Ultraviolet–Visible diff use refl ectance spectroscopy suggests that nanostructured BiVO4 particles possess strong energy absorption properties both in visible and ultraviolet region. The particles show red shift of band gap as the calcination temperature rises and possible reasons have been discussed. Energydispersive X-ray spectroscopy confi rms presence of Bi, V, and O without any contaminant, while particle’s morphology was investigated using Field Emission Scanning Electron Microscope.

A COMMON FIXED POINT THEOREM IN AN M*-METRIC SPACE AND AN APPLICATION

Gharib M. Gharib,Abed Al-Rahman M. Malkawi,Ayat M. Rabaiah,Was A. Shatanawi,Maha S. Alsauodi 경남대학교 기초과학연구소 2022 Nonlinear Functional Analysis and Applications Vol.27 No.2

In this paper, we introduce the concept of M*-metric spaces and how much the M*-metric and the b-metric spaces are related. Moreover, we introduce some ways of generating M*-metric spaces. Also, we investigate some types of convergence associated with M*-metric spaces. Some common fixed point for contraction and generalized contraction mappings in M*-metric spaces. Our work has been supported by many examples and an application.

Mutant divergence in sunflower induced through gamma radiation

Habib Sheikh Hasna,Akanda Abdul Latif,Roy Pryanka,Kulsum Ummy,Rohman Motiar,Rahman M. M. 한국작물학회 2023 Journal of crop science and biotechnology Vol.26 No.3

Gamma radiation-induced mutation divergence was studied in sunfower variety BARI Surjamukhi-2. A number of treatment combinations from T1 to T5 (100 to 500 gamma doses) were applied at the laboratory of Institute of Food and Radiation Biology, Ganakbari, Savar, and M1 and M2 generations were grown at the research feld of Oilseed Research Centre (ORC), Bangladesh Agricultural Research Institute (BARI), Gazipur. Compared to the control plant, most of the mutagenic treatments in M1 generation showed a gradual reduction of mean performance. The seeds treated with 100 and 200 gamma doses produced taller plant than control, while seeds treated with 400 and 500 gamma doses did not survive or produce any seed to evaluate in further generation. The T3-treated (300 gamma dose) seeds produced plants of average height. Dwarfsm and semi dwarfsm being the most desirable traits in sunfower, the seeds obtained in T3 were grown to generate M2 population for further evaluation. In M2 generation, compared to control, plant improvement was recorded for plant stature (short and robust), increased head size, seed number, and seed yield. Besides quantitative divergence, qualitative divergence was also very obvious—such as diferent size, shape and orientation in head character, robust stem, broad leaf, short internode, tall mutants, branching mutants, diferent size, shape and seed coat color compared to non-treated seed. All these diverse mutants may have breeding value and be put into further research.

Potential hazard of volatile organic compounds contained in household spray products

Rahman, M.M.,Kim, K.H. Pergamon Press ; Elsevier [distribution] 2014 Atmospheric environment Vol.85 No.-

To assess the exposure levels of hazardous volatile pollutants released from common household spray products, a total of 10 spray products consisting of six body spray and four air spray products have been investigated. The body spray products included insect repellents (two different products), medicated patch, deodorant, hair spray, and humectant, whereas the air spray products included two different insecticides (mosquito and/or cockroach), antibacterial spray, and air freshener. The main objective of this study was to measure concentrations of 15 model volatile organic compounds (VOCs) using GC/MS coupled with a thermal desorber. In addition, up to 34 'compounds lacking authentic standards or surrogates (CLASS)' were also quantified based on the effective carbon number (ECN) theory. According to our analysis, the most common indoor pollutants like benzene, toluene, styrene, methyl ethyl ketone, and butyl acetate have been detected frequently in the majority of spray products with the concentration range of 5.3-125 mg L<SUP>-1</SUP>. If one assumes that the amount of spray products released into air reaches the 0.3 mL level for a given space size of 5 m<SUP>3</SUP>, the risk factor is expected to exceed the carcinogenic risk level set for benzene (10<SUP>-5</SUP>) by the U.S. EPA.

Natural wind-driven ultra-compact and highly efficient hybridized nanogenerator for self-sustained wireless environmental monitoring system

Rahman, M. Toyabur,Salauddin, Md,Maharjan, P.,Rasel, M.S.,Cho, Hyunok,Park, Jae Yeong Elsevier 2019 Nano energy Vol.57 No.-

<P><B>Abstract</B></P> <P>Owing to the climate change and energy crisis, harvesting energy from our surroundings and the construction of self-powered wireless environmental monitoring systems are promising approaches in modern times. In this paper, an ultra-compact highly efficient miniaturized windmill comprising a hybridized nanogenerator (MW-HNG) is reported based on three conversion mechanisms <I>i.e.</I> triboelectric nanogenerator (TENG), piezoelectric nanogenerator (PENG), and electromagnetic generator (EMG). The MW-HNG is designed as a 3D-printed fully-enclosed structure for the natural wind energy harvesting by converting into rotational motion: all harvesting units reside in a common rotation system to effectively and simultaneously produce electricity. At a wind speed of 6 m/s, the flexible-blade-based hybridization-mode (contact–lateral sliding–separation–contact) TENG and coupled PENG can generate maximal power values of 1.67 mW and 1.38 mW at optimal load resistances of 10 MΩ and 330 KΩ, respectively. In contrast, the multipole-magnet-based EMG can obtain a maximal output power of 268.6 mW at 180 Ω. The MW-HNG demonstrates a quick charging ability for capacitors and the capability to feed hundreds of LEDs. Further, a self-powered wireless sensor system is developed for real-time environmental monitoring by combining an MW-HNG, a customized power management circuit, and wireless sensor unit (a smartphone to display sensor data). Our proposed MW-HNG is suitable for self-powered wireless sensor networks (WSNs) in the subway system by generating high-power electrical output from moving-induced wind mechanical energy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3D-printed fully-enclosed hybridized nanogenerator for wind energy harvesting. </LI> <LI> Integrated three popular conversion mechanisms into a single energy harvesting unit. </LI> <LI> Flexible-blade-based hybridizing TENG, coupled PENG and multipole-magnet-based EMG. </LI> <LI> Potential application in subway system for illuminating billboard and animated LEDs. </LI> <LI> Self-powered wireless environmental sensor with real-time monitoring <I>via</I> smartphone. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of Lubricant with Nanodiamond Particles in Sliding Friction

M. H. Adzaman,A. Rahman,Y. Z. Lee,S. S. Kim 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.4

This paper presents the experimental effects of lubricant with nanodiamond particles in sliding friction. In order to improve the performance of lubricants many additives are used, such as MoS2, cadmium chloride, indium, sulfides, and phosphides. These additives are harmful to human health and to the environment, so alternatives are necessary. One such alternative is nanodiamond powder, which has a large surface area. In order to investigate the effect of nanodiamonds in lubricants under sliding friction, they are dispersed in the lubricant at a variety of concentrations (0 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1 wt%) using the matrix synthesis method. Friction and wear tests are performed according to the ASTM G99 method using a pin-on-disc tester at room temperature. The specimens used in this experiment are AISI 52100 ball bearings and AISI 1020 steel discs. During the test, lubricant mixed with nanodiamond is supplied constantly to keep the two bodies separated by a lubricant film. To maintain boundary lubrication, the speed is set to 0.18 m/s and a load of 294 N is applied to the disc through the pin. Results are recorded by using workbench software over the test duration of 10 minutes. Experimental results show that when the concentration of nanodiamond increases, the coefficient of friction decreases. However, above a nanodiamond concentration of 0.5 wt%, both the coefficient of friction and wear volume increase. From this experiment, the optimum concentration of nanodiamond showing a minimum coefficient of friction of 0.09 and minimum wear volume of 0.82 nm2 was 0.5 wt%.

Molecular Characterization of Selected Local and Exotic Cattle Using RAPD Marker

Khatun, M. Mahfuza,Hossain, Khondoker Moazzem,Rahman, S.M. Mahbubur Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.6

In order to develop specific genetic markers and determine the genetic diversity of Bangladeshi native cattle (Pabna, Red Chittagong) and exotic breeds (Sahiwal), randomly amplified polymorphic DNA (RAPD) analysis was performed using 12 primers. Genomic DNA was extracted from 20 cattle (local and exotic) blood samples and extracted DNA was observed by gel electrophoresis. Among the random primers three were matched and found to be polymorphic. Genetic relations between cattle's were determined by RAPD polymorphisms from a total of 66.67%. Statistical analysis of the data, estimating the genetic distances between cattle and sketching the cluster trees were estimated by using MEGA 5.05 software. Comparatively highest genetic distance (0.834) was found between RCC-82 and SL-623. The lowest genetic distance (0.031) was observed between M-1222 and M-5730. The genetic diversity of Red Chittagong and Sahiwal cattle was relatively higher for a prescribed breed. Adequate diversity in performance and adaptability can be exploited from the study results for actual improvement accruing to conservation and development of indigenous cattle resources.