Fragmentation Behavior Studies of Chalcones Employing Direct Analysis in Real Time (DART)

A. F. M. Motiur Rahman,Mohamed W. Attwa,Pervez Ahmad,Mohammad Baseeruddin,Adnan A. Kadi 사단법인 한국질량분석학회 2013 Mass spectrometry letters Vol.4 No.2

Chalcones are naturally occurring, biologically active molecules generating interest from a wide range of researchapplications including synthetic methodology development, biological activity investigation and studying fragmentation patterns. Inthis article, a series of chalcones has been synthesized and their fragmentation behavior was studied using modern ambient ionizationtechnique Direct Analysis in Real Time (DART). DART ion source connected with an ion trap mass spectrometer wasused for the fragmentation of various substituted chalcones. The chalcones were introduced to the DART source using a glasscapillary without sample preparation step. All the chalcones showed prominent molecular ion peaks [M]•+ corresponding to thestructures. Multistage mass spectral data MSn (MS2 and MS3) were collected for all the chalcones studied. The chalcones withsubstitutions at 3, 4 or 5 positions gave product ion peaks with the loss of a phenyl radical (Ph•) by radical initiated α-cleavage,while substitution at 2 position of chalcone in the A-ring gave a product ion peak with the loss of substituted styryl radical(PhCH = CH•). In case of the chalcones with the substituent at 4 positions in A and B rings gave both types of fragmentation patterns. In conclusion, chalcones can be easily characterized using modern DART interface in very short time and efficientlywithout any cumbersome sample pretreatment.

Fragmentation Behavior Studies of Chalcones Employing Direct Analysis in Real Time (DART)

Motiur Rahman, A.F.M.,Attwa, Mohamed W.,Ahmad, Pervez,Baseeruddin, Mohammad,Kadi, Adnan A. Korean Society for Mass Spectrometry 2013 Mass spectrometry letters Vol.4 No.2

Chalcones are naturally occurring, biologically active molecules generating interest from a wide range of research applications including synthetic methodology development, biological activity investigation and studying fragmentation patterns. In this article, a series of chalcones has been synthesized and their fragmentation behavior was studied using modern ambient ionization technique Direct Analysis in Real Time (DART). DART ion source connected with an ion trap mass spectrometer was used for the fragmentation of various substituted chalcones. The chalcones were introduced to the DART source using a glass capillary without sample preparation step. All the chalcones showed prominent molecular ion peaks $[M]^{{\cdot}+}$ corresponding to the structures. Multistage mass spectral data $MS^n$ ($MS^2$ and $MS^3$) were collected for all the chalcones studied. The chalcones with substitutions at 3, 4 or 5 positions gave product ion peaks with the loss of a phenyl radical ($Ph^{\cdot}$) by radical initiated ${\alpha}$-cleavage, while substitution at 2 position of chalcone in the A-ring gave a product ion peak with the loss of substituted styryl radical (PhCH = $CH^{\cdot}$). In case of the chalcones with the substituent at 4 positions in A and B rings gave both types of fragmentation patterns. In conclusion, chalcones can be easily characterized using modern DART interface in very short time and efficiently without any cumbersome sample pretreatment.

A comparative study of mechanical behavior of ABS material based on UVC sterilization for medical usage

Mohamed A. Aboamer,Doaa H. Elgohary,Ali Abdullah Almukil,Ahmed A. Aboamer,Ibrahim M Alarifi,Mohsen Bakouri,Nader A. Rahman Mohamed 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

This study aims to examine the mechanical properties of acrylonitrile butadiene styrene specimens using ASTM 638, 695, and 790. UVC radiation was also used as a sterilizing method. The fused deposition modeling of 3D-printed polymerize with 30 % filling was used to manufacture 30 specimens for tensile, compression, and bending. Half of the specimens were treated with UVC, whereas the other half were not. The chosen dosage of 13.5 J/cm 2 with an exposure time of 48 min corresponds to 3650 sterilization treatments or 10 years of sterilization. The average ultimate stress in the tensile test, compression test, and bending test was 34.5 ± 7.4, 25.4 ± 0.5, and 24.5 ± 2.1 Mpa, respectively. The analysis of variance test shows that UVC radiation has a demonstrable influence on tensile specimens, with a P-value of 0.012, which is less than the significance threshold of 0.05. Thus, the null hypothesis is rejected.

Control and Modulation of Three to Asymmetrical Six-Phase Matrix Converters based on Space Vectors

Mohammed A. Al-Hitmi,Khaliqur Rahman,Atif Iqbal,Nasser Al-Emadi 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

This paper proposes the modulation and control of a three-to-six-phase matrix converter with an asymmetrical six-phase output. The matrix converter (MC) outputs consist of two sets of three-phase spatially shifted by 300, where the two sets have two isolated neutrals. The space vector approach is considered for the modeling and subsequent modulation of the three-to-six phase MC. The intelligent selection of voltage space vectors is made to synthesize the reference voltages and to obtain a sinusoidal output. The dwell times of selected voltage space vectors are adjusted in such a way that the effect of the second and the third auxiliary plane vectors (i.e., x1-y1, and x2-y2) are nullified. To achieve the maximum output voltage gain and to ensure that no reactive power is drawn from the utility supply, the input side power factor is maintained at unity. Nevertheless, the source side power factor is controllable. The modulation technique is implemented in dSPACE working in conjunction with a FPGA. Hardware results that validate the proposed control algorithm are discussed.

Lean Cu-immobilized Pt and Pd films/–H+ Conducting Membrane Assemblies: Relative Electrocatalytic Nitrate Reduction Activities

Mohammad A. Hasnat,Sami Ben Aoun,Mohammed M. Rahman,Abdullah M. Asiri,Norita Mohamed 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-

Asymmetric reactors having the configuration (PtjNafionjM–Cu, M = Pt, Pd) were designed and appliedto the electrocatalytic nitrate reduction reaction (NRR) with no supporting electrolyte. Theelectrochemically–fabricated Cu–M (M = Pt, Pd) catalysts showed a highly-efficient catalytic activityby effectively reducing more than ca. 99% of nitrate ions, under static-reactor conditions, with first-orderrate constants of ca. 0.040 min 1 and ca. 0.057 min 1 for Cu–Pt and Cu–Pd, respectively. Similarreactivity trends were observed under flow mode irrespective of flow rates while NRR rates werepredominantly controlled by diffusion-limited mass-transfer. A maximum of ca. 93% nitrate removal atCu–Pd catalyst was achieved within ca. 60 min. The comparatively lower CuO content of ca. 9%, asconfirmed by XANES, resulted in a greater number of free NRR active sites inducing the superior catalyticactivity of the Cu–Pd catalyst. On the other hand, NRR product selectivity investigations showed that Cu–Pd catalyst was highly ammonia–selective with a maximum of ca. 24% selectivity at a flow rate of0.1 mL min 1, while Cu–Pt catalyst was much selective to intermediate nitrite ions reaching a maximumof ca. 35% selectivity at the same flow rate.

Efficient electrochemical detection of L-lactic acid using platinum nanoparticle decorated Chitosan/ZnTiO3 nanocomposites

M. Faisal,M.M. Alam,Jahir Ahmed,Abdullah M. Asiri,S.A. Alsareii,Raja Saad Alruwais,Norah Faihan Alqahtani,Mohammed M. Rahman,Farid A. Harraz 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Herein, a facile L-lactic acid electrochemical sensor based on Pt-nanoparticles (NPs)@Chitosan/ZnTiO3nanocomposites (NCs) coated on a glassy carbon electrode (GCE) is demonstrated. Ultra-sonicationmethod followed by irradiation using an Osram Hg-lamp was applied to prepare Pt-NPs@Chitosan/ZnTiO3 NCs, and the characterization of prepared NCs was executed by Field Emission ScanningElectron Microscopy FESEM, Energy Dispersive Spectroscopy EDS, Transmission Electron MicroscopyTEM, High Resolution Transmission Electron Microscopy HRTEM, Fourier Transform InfraredSpectroscopy FTIR, Ultraviolet–visible spectroscopy UV–vis., and X ray Diffraction XRD analysis. A linearcurrent versus potential responses relation was obtained in a concentration range of L-lactic acid of 0. 30 2.40 mM at differential pulse voltammetric (DPV) analysis in a pH 7.0 buffer medium and resultedconcentration range was defined as the dynamic detection range (LDR) for L-lactic acid analysis. The Llacticacid sensor sensitivity (0.4529 lAlM-1cm2), limit of detection (LOD; 22.36 ± 1.12 lM), and limitof quantification (LOQ; 79.88 lM) were obtained. Besides this, the sensor reproducibility and responsetime were found to be reliable. Finally, the assembled sensor probe was validated by the testing of realsamples, which exhibited acceptable and satisfied results. It is introduced a new route for the detection ofchemicals using novel nanocomposite materials by electrochemical approach for the safety of healthcarefields in a broad scales.

Synthesis and Reactions of New Thienopyridines, Pyridothieniopyrimidines and Pyridothienotriazines

Bakhite, E.A.,Abdel Rahman, A.E.,Mohamed, O.S.,Thabet, E.A. Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.12

4-Aryl-3-cyano-6-(2'-thienyl)-pyridine-2(1H)-thiones(1a-c) were reacted with phenacyl bromide, chloro-N-arylacetanmides or 2-chloroacetylaminopyridine to furnish 2-functionalized 3-amino-4-aryl-6-(2'-thienyl)-thieno[2,3-b]pyridines 4a-c and 5a-c or 5d respecitively. The compounds 5a-d underwent different sequence of reactions to produce a variety of thienylpyridothienopyrimidines and, thienylpyridothienotriazines. Some of the prepared compounds were tested in vitro for their antimicrobial activities.

Control and Modulation of Three to Asymmetrical Six-Phase Matrix Converters based on Space Vectors

Al-Hitmi, Mohammed A.,Rahman, Khaliqur,Iqbal, Atif,Al-Emadi, Nasser The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

This paper proposes the modulation and control of a three-to-six-phase matrix converter with an asymmetrical six-phase output. The matrix converter (MC) outputs consist of two sets of three-phase spatially shifted by $30^0$, where the two sets have two isolated neutrals. The space vector approach is considered for the modeling and subsequent modulation of the three-to-six phase MC. The intelligent selection of voltage space vectors is made to synthesize the reference voltages and to obtain a sinusoidal output. The dwell times of selected voltage space vectors are adjusted in such a way that the effect of the second and the third auxiliary plane vectors (i.e., x1-y1, and x2-y2) are nullified. To achieve the maximum output voltage gain and to ensure that no reactive power is drawn from the utility supply, the input side power factor is maintained at unity. Nevertheless, the source side power factor is controllable. The modulation technique is implemented in dSPACE working in conjunction with a FPGA. Hardware results that validate the proposed control algorithm are discussed.

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.

Low dimensional Ni-ZnO nanoparticles as marker of toxic lead ions for environmental remediation

Mohammed M. Rahman,Sher Bahadar Khan,Hadi M. Marwani,Abdullah M. Asiri,Khalid A. Alamry,Malik Abdul Rub,Anish Khan,Aftab Aslam Parwaz Khan,Abdullah H. Qusti 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.3

We have synthesized Ni-ZnO nanoparticles (NPs) by a wet-chemical route using reducing agents. Thestructural and optical properties of Ni-ZnO NPs were investigated by various conventional methods. Theanalytical potential of the Ni-ZnO NPs was studied for a selective detection of toxic Pb(II) ion usingrecognized ICP-OES method for environmental remediation. Data obtained from the selectivity studyindicated that the selectivity of Ni-ZnO NPs phase was the most toward Pb(II) ion. However, theadsorption isotherm data of Pb(II) on Ni-ZnO NPs phase was good-match with the Langmuir-Adsorption-Isotherm, strongly supporting that the adsorption process was mainly monolayer on homogeneousadsorbent surfaces.