Highly selective, rapid and simple colorimetric detection of Fe3+ in fortified foods by L-Cysteine modified AuNP

N Borah, AJ Kalita, AK Guha, MR Das, C Tamuly

Microchemical Journal , vol: 179 , 107480, 2022 , 10.1016/j.microc.2022.107480

Abstract:


Phosphoric acid assisted synthesis of fluorescent carbon dots from waste biomass for detection of Cr (VI) in aqueous media

J. Goswami, S. S. Rohman, A. K. Guha, P. Basyach, K. Sonowal, S. P. Borah, L. Saikia, P. Hazarika

Materials Chemistry and Physics , vol: 286 , 126133, 2022 , 10.1016/j.matchemphys.2022.126133

Abstract:


Viability of half‐sandwich complex of heavier group‐14 elements (SiPb) with neutral Be3 ring and its potential application as H2 storage material

A. J. Kalita, P. Dutta, F. Yashmin, R. R. Borah, R. P. Deka, A. K. Guha

International Journal of Quantum Chemistry , vol: 122 , e26878, 2022 , 10.1002/qua.26878

Abstract:


Novel thioether Schiff base transition metal complexes: Design, synthesis, characterization, molecular docking, computational, biological and catalytic studies

A. Singh, H. P. Gogoi, P. Barman, A. K. Guha

Applied Organometallic Chemistry , vol: 36 , e6673, 2022 , 10.1002/aoc.6673

Abstract:


Rhodium (I) carbonyl complexes containing amino acid ester ligands: synthesis, reactivity and DFT studies

B. J, Sarmah, J. Nath, A. K. Guha

Journal of Coordination Chemistry , 2022 , 10.1080/00958972.2022.2059358

Abstract:


Condensation Product of 1-Naphthaldehyde and 3-Aminophenol: Fluorescent “on” Probe for Ce3+ and “off” Probe for Dichromate (Cr2O72−)

P. Bordoloi, A. K. Guha, D. K. Das

Journal of Fluorescence , vol: 32 , 1189, 2022 , 10.1007/s10895-022-02927-0

Abstract:


Chirally modified cobalt-vanadate grafted on battery waste derived layered reduced graphene oxide for enantioselective photooxidation of 2-naphthol: Asymmetric induction through non-covalent interaction

M. J. Baruah, T. J. Bora, G. Gogoi, N. Hoque, N. K. Gour, S. K. Bhargava, A. K. Guha, J. K. Nath, B. Das, K. K. Bania

Journal of Colloid and Interface Science , vol: 608 , 1526, 2022 , 10.1016/j.jcis.2021.10.091

Abstract:


Aromatic B3 Ring Stabilized Group 2 Dimer, B3-YY-B3 (Y= Be, Mg, Ca)

R. R. Borah, A. J. Kalita, F. Y.asmin, K. Sarmah, R. P. Deka, D. Konwar, A. K. Guha

Polyhedron , vol: 215 , 115681, 2022 , 10.1016/j.poly.2022.115681

Abstract:


Tetrametallic Copper Complex to Nanoscale Copper: Selective and Switchable Dehydrogenation‐Hydrogenation under Light

A. R. Shelte, K. Sarmah, A. K. Guha, S. Pratihar

Chemistry–A European Journal , vol: 28 , e202103383, 2022 , 10.1002/chem.202103383

Abstract:


Planar Pentacoordinate Zinc Group Elements Stabilized by Multicentric Bonds

A. J. Kalita, I. Baruah, K. Sarmah, R. R. Borah, F. Yashmin, A. K. Guha

Inorganic chemistry , vol: 61 , 1259, 2022 , 10.1021/acs.inorgchem.1c03426

Abstract:


Efficient hydroxylation of benzene to phenol by H 2 O 2 using Ni-doped CuWO 4 on carbon nitride as a catalyst under solar irradiation and its structure–activity relationship

P. Basyach, A. K. Guha, S. Borthakur, L. Kalita, P. Chetia, K. Sonowal, L. Saikia

Journal of Materials Chemistry A , vol: 10 , 10790, 2022

Abstract:


Highly sensitive and selective colorimetric detection of dual metal ions (Hg 2+ and Sn 2+) in water: an eco-friendly approach

R. Paw, M. Hazarika, P. K. Boruah, A. J. Kalita, A. K. Guha, M. R. Das, C. Tamuly

RSC advances , vol: 12 , 11345, 2022 , 10.1039/D2RA90034C

Abstract:


Missing Recipe in the Na-B Bond in NaBH3– Cluster

A. J. Kalita, K. Sharma, R. R. Borah, F. Yashmin, L. J. Mazumder, S. K. Purkayastha, K. Das, T. Dutta, A. K. Guha

Chemistry Select , vol: 7 , e202201536, 2022 , 10.1002/slct.202201536

Abstract:


Nanofiber induced enhancement of electrical and electrochemical properties in polymer gel electrolytes for application in energy storage devices

S. Borah, A. K. Guha, L. Saikia, M. Deka

Journal of Alloys and Compounds , vol: 886 , 161173, 2021 , 10.1016/j.jallcom.2021.161173

Abstract:


σ-Aromaticity in planar pentacoordinate aluminium and gallium clusters

AJ Kalita, K Sarmah, F Yashmin, RR Borah, I Baruah, RP Deka, AK Guha

Scientific Reports , vol: 12 , 1, 2022 , 10.1038/s41598-022-14430-4

Abstract:


Insights into the Interaction between Polyphenols and β-Lactoglobulin through Molecular Docking, MD Simulation, and QM/MM Approaches

I Baruah, C Kashyap, AK Guha, G Borgohain

ACS Omega , 2022 , 10.1021/acsomega.2c00336

Abstract:


Neutral all metal aromatic half-sandwich complexes between alkaline earth and transition metals: an ab initio exploration

Amlan Jyoti Kalita, Prem Prakash Sahu, Ritam Raj Borah, Shahnaz Sultana Rohman, Chayanika Kashyap, Sabnam Swabaka Ullah, Indrani Baruah, Lakhya Jyoti Mazumder, Dimpul Konwar, Ankur Kanti Guha

Structural Chemistry , 2021 , 10.1007/s11224-021-01807-w

Abstract:


Phosphonate functionalized N-heterocyclic carbene Pd (II) complexes as efficient catalysts for Suzuki-Miyaura cross coupling reaction

B Bhattacharyya, AJ Kalita, AK Guha, N Gogoi

Journal of Organometallic Chemistry , 2021 , 10.1016/j.jorganchem.2021.122067

Abstract:


Fluorescent Sensors for Hg2+ and Cu2+ Based on Condensation Products of 4H-1, 2, 4 Triazole-4-Amine and Carboxylated Benzoic Acids

S Deka, AK Guha, DK Das

Journal of Fluorescence , vol: 31 , 1937, 2021

Abstract:


Fe (III) superoxide radicals in halloysite nanotubes for visible-light-assisted benzyl alcohol oxidation and oxidative CC coupling of 2-naphthol

MJ Baruah, TJ Bora, R Dutta, S Roy, AK Guha, KK Bania

Molecular Catalysis , vol: 515 , 111858, 2021

Abstract:


Magnetically separable ZnFe2O4 nanoparticles: A low cost and sustainable catalyst for propargyl amine and NH-triazole synthesis

Roktopol Hazarika, Anirban Garg, Swadhin Chetia, Parmita Phukan, Akshay Kulshrestha, Arvind Kumar, Ankur Bordoloi, Amlan Jyoti Kalita, Ankur Kanti Guha, Diganta Sarma

Applied Catalysis A: General , vol: 625 , 118338, 2021

Abstract:


Green synthesis of a vanadium (V) Schiff base complex by grinding method: study on its catalytic and anti-bacterial activity

JJ Boruah, ZS Bhatt, CR Nathani, VJ Bambhaniya, AK Guha, SP Das

Journal of Coordination Chemistry , vol: 74 , 2055, 2021

Abstract:


Fuzzy risk analysis based on a similarity measure of fuzzy numbers and its application in crop selection

Mridul Krishna Gogoi, Rituparna Chutia

Engineering Applications of Artificial Intelligence , vol: 107 , 104517, 2022 , 10.1016/j.engappai.2021.104517

Abstract:

Crop selection is an important task for optimum output, as it involves various risk factors. Hence, it requires performing risk analysis on crop selection. Generally, these risk factors involved in crop selection can be assessed by probabilistic methods, which require lots of data and are very expensive. As such, an alternative to probabilistic analysis, possibilistic analysis can be performed where the data involved are linguistic variables. These linguistic variables can be observed as fuzzy numbers, in which case fuzzy risk analysis plays an important role. Generally, in the process of fuzzy risk analysis, the final risks are fuzzy numbers, which have to be transformed into linguistic variables, so that the final risks become communicable to the general audience. The similarity measure is such a tool that helps in the process of transformation. Literature reveals lots of similarity measures since its development. This happens as there is not a single universally accepted measure. In this work, an attempt is being made to develop a novel measure of similarity between fuzzy numbers. Generally, the existing measures do not comply with the basic properties of a similarity measure. Nevertheless, the current measure oath to follow some reasonable properties of the similarity measure.


Two new similarity measures for intuitionistic fuzzy sets and its various applications

Brindaban Gohain, Rituparna Chutia, Palash Dutta, Surabhi Gogoi

International Journal of Intelligent Systems , 2022 , 10.1002/int.22802

Abstract:

In this paper, two new tools of decision-making problems, namely similarity measures between intuitionistic fuzzy sets, are being forwarded. In general, parameters like the difference of membership degrees and the difference of nonmembership degrees are very prominent factors while constructing these tools. Various studies are evident which tried to incorporate concepts like the cross-evaluation factor and the difference of hesitancy factors. In some studies, it is claimed that the use of the hesitancy parameter is not proper. In this study, the hesitancy factor is being incorporated effectively. Furthermore, another prominent parameter is the difference in the minimum of cross-evaluation factor along with the difference in the maximum of cross-evaluation factor, which is not being used earlier. The incorporation of these parameters produces outperforming results, and the limitations of the existing methods are overcome. The numerical examples discussed to show the performance of the proposed distance measure. Furthermore, the applicability of the proposed similarity measures is exhibited by various applications in pattern recognition, face-mask selection, and clustering problems.


Ranking of generalized fuzzy numbers based on accuracy of comparison

M. Adabitabar Firozja, F. Rezai Balf, B. Agheli, R. Chutia

Iranian Journal of Fuzzy Systems , vol: 19 , 49-61, 2022 , 10.22111/IJFS.2022.6787

Abstract:

Ranking generalized fuzzy numbers plays an important role in many applied models and, in particular, decision-making procedures. In ranking process of two generalized fuzzy numbers, it is natural to compare the sets of values in support of two generalised fuzzy numbers. Accordingly, the comparison of a real number and a generalised fuzzy number as well as two generalised fuzzy numbers have to be considered. On the other hand, it is seen that a definitive process of comparison of a real number and a generalised fuzzy number, as well as two generalised fuzzy numbers, is not possible. So in this study, a method for comparing a real number and a generalised fuzzy number with a degree of accuracy (between a zero and one) is defined and then the method is generalized to compare two generalised fuzzy numbers. In general, an index to rank a real number and generalised fuzzy number is constructed. Eventually, this index is extended to rank two generalised fuzzy numbers based on the concept of accuracy of comparison. The advantage of our method is that it can compare two generalised fuzzy numbers with an accuracy of comparison. Also, a definition is introduced to make a definitive comparison. Finally, the proposed method is illustrated by some numerical examples.


Numerical investigation on the thermal transportation of MHD Cu/Al2 O3-H2O Casson-hybrid-nanofluid flow across an exponentially stretching cylinder incorporating heat source.

Ashish Paul, Tusar Kanti Das, Jintu Mani Nath

Physica Scripta , 2022 , https://doi.org/10.1088/1402-4896/ac7981

Abstract:


Even and odd nonautonomous NLSE hierarchy and reversible transformations

S Nandy, GK Saharia, S Talukdar, R Dutta, R Mahanta

Optik 247 , vol: 167928 , 2.443, 2021 , https://doi.org/10.1016/j.ijleo.2021.167928

Abstract:

Abstract Under investigation are the nonautonomous Nonlinear Schrödinger equation (NLSE) hierarchies. We have presented the soliton solution of the hierarchy in the most generalized form, namely in terms of the spectral parameter of nonautonomous NLSE spectral problem. We analysed crucial differences between the even order hierarchies and the odd order hierarchies and the corresponding solutions. We have also presented the generalized reversible transformations, which transform the nonautonomous NLSE hierarchy into variable coefficient autonomous NLSE hierarchy. We found that the reversible coordinate transformations are monotonic for odd order hierarchies but not strictly monotonic for even order hierarchies or for a combination of the both. The Jacobian of the transformation is, however, unity in all the transformations. We have identified a set of constraints among the dispersion and the nonlinear coefficients of the general nonautonomous NLSE hierarchy, which are preserved under the transformations. We hope that our analysis provides a universal mathematical platform to study diverse physical systems in nonlinear optics, plasma physics, atomic physics and climate physics.


Phototransferred thermoluminescence characteristics of microcline (KAlSi3O8) under 470 nm blue- and 870 nm infrared-light illumination

J.M. Kalita, M.L. Chithambo

Applied Radiation and Isotopes , vol: 181 , 110070, 2022 , https://doi.org/10.1016/j.apradiso.2021.110070

Abstract:

We report phototransferred thermoluminescence (PTTL) induced in microcline by 470 nm blue- and 870 nm infrared-light. A conventional thermoluminescence (TL) glow curve measured from a sample irradiated to 40 Gy produces five composite TL glow peaks P1, P2, P3, P4 and P5 at 90, 123, 166, 298 and 391 °C respectively. The sample produces PTTL peaks also identified as P1, P2, P3 and P4 following illumination by blue or infrared light after irradiation to 40 Gy and preheating to 400 °C. Step-annealing suggests the presence of deep electron traps associated with a signal beyond 500 °C. However, preheating to 500 °C and exposure to blue or infrared light does not produce significant PTTL peaks. For doses between 40 Gy and 100 Gy, the maximum PTTL is emitted within 60 and 150 s of blue light illumination. On the other hand, the same feature under the infrared light illumination occurs within 100–200 s of illumination. PTTL peaks P1, P2, P3 and P4 reproduced under blue light illumination have a linear dose response between 10 Gy and 100 Gy and those reproduced under infrared light illumination have a superlinear dose response between 10 and 100 Gy. In contrast, donor peak P5 in both cases follows sublinear dose response within the same dose range. Fading of PTTL peaks P1, P2, P3 and P4 as well as the donor peak P5 are negligibly small under blue light illumination compared to that of infrared light illumination. PTTL glow curves are also found to be properly reproducible.


Thermoluminescence and optically stimulated luminescence of colemanite-rich borate mineral

J.M. Kalita, Ş. Kaya-Keleş, G.Ö. Çakal, N. Meriç, G.S. Polymeris

Journal of Luminescence , vol: 242 , 118580, 2022 , https://doi.org/10.1016/j.jlumin.2021.118580

Abstract:

We report structural, chemical composition, thermal decomposition and stimulated luminescence properties of a colemanite-rich borate (Ca2B6O11•5H2O) mineral collected from Kırka, Eskişehir region of Turkey. X-ray diffraction shows that the colemanite phase has a monoclinic crystal structure. Further, Raman spectroscopic analysis reveals that the sample contains 45.83% of B and 17.93% of CaO. Thermogravimetric analysis indicates that there is removal of hydroxyl groups followed by explosive release of water from the sample at temperature below 200 °C. The sample produces thermoluminescence (TL) and optically stimulated luminescence (OSL) following beta irradiation. A TL glow curve measured at 1 °C/s consists of five glow peaks at ∼145, 175, 215, 267 and 322 °C. The activation energy associated with the peaks are ∼0.73, 0.77, 0.83, 0.90 and 1.19 eV respectively and the frequency factors are ∼106 ‒ 108 s−1. The lifetimes of the traps at room temperature are estimated to be ∼1.42 days to 2.33 × 104 years. The peaks at ∼175, 215 and 267 °C show supralinear dose response between 32 and 16000 Gy whereas the ones at ∼145 and 322 °C show supralinearity between 32 and 2048 Gy. Analysis of the OSL decay curve shows that the decay curve has a ‘fast’-, ‘medium’- and a ‘slow’ component. The dose response of the fast component is found to be linear within 2–4096 Gy and that of the medium- and slow components are found to be superlinear between 2 Gy and 4096 Gy.


Light-induced inter-electron-trap charge movement in annealed Al2O3:C,Mg

M.L. Chithambo, A.J. Lontsi Sob, J.M. Kalita

Physica B: Condensed Matter , vol: 624 , 413438, 2022 , https://doi.org/10.1016/j.physb.2021.413438

Abstract:

Inter-electron-trap charge movement induced under phototransferred thermoluminescence (PTTL) in Al2O3:C,Mg annealed at 700 and 900 °C is reported. Such annealing modifies the emission spectrum and electron trapping states in Al2O3:C,Mg. The glow curve of Al2O3:C,Mg annealed at 700 °C has eight peaks at 46, 76, 100, 170, 199, 290, 330 and 375 °C respectively. In comparison, that of the sample annealed at 900 °C has nine at 49, 80, 100, 174, 206, 235, 290, 335 and 375 °C. The peaks are labelled I, II, III … in that order. Only peaks I-IV re-appear under phototransfer. The PTTL is analysed qualitatively as well as by computational and phenomenological models as systems of an acceptor and multiple donors. Point defects that likely contribute to emergence of PTTL are discussed and are deduced to lie mostly in the oxygen sub-lattice.


Phototransferred thermoluminescence of BeO: Time-response profiles and mechanisms

M.L. Chithambo, J.M. Kalita

Journal of Applied Physics , vol: 130 , 195101, 2021 , https://doi.org/10.1063/5.0067758

Abstract:

Phototransferred thermoluminescence (PTTL) from BeO is reported. The conventional TL glow curve has five peaks, I–V, at 50, 182, 283, 437, and 535 °C when measured at 1 °C s−1 The dominant one is peak II. Only the first three reappear under phototransfer. Electron traps for peaks IV and V weakly contribute to the PTTL. The PTTL at peak III, supposedly associated with these weak donors, is counterintuitively intense. All PTTL peaks are affected by light-induced fading, thermal quenching, and all but peak II by thermal fading. The activation energy for thermal quenching was found as 0.56±0.020.56±0.02, 0.53±0.050.53±0.05, and 0.94±0.07eV0.94±0.07eV using peaks I, II, and III, respectively. Electronic processes relevant in the PTTL of BeO are discussed. PTTL time-response profiles are analyzed using systems of coupled linear differential equations as well as by theoretical modeling.


Thermally-assisted optically stimulated luminescence from deep electron traps in microcline

J.M. Kalita, M.L. Chithambo

Radiation Measurements , vol: 154 , 106786, 2022 , https://doi.org/10.1016/j.radmeas.2022.106786

Abstract:

We report thermally-assisted optically stimulated luminescence (TA-OSL) of microcline (KAlSi3O8) from Sri Surya Pahar hill in Assam state, North-Eastern India. To study the luminescence associated with deep electron traps, a beta-irradiated sample was first heated to 500 °C at 1 oCs−1 to deplete all electron traps accessible up to this temperature. Thereafter, the sample was illuminated by 470 nm blue- or 870 nm infrared light at various temperatures between 30 and 300 °C and TA-OSL associated with deep electron traps recorded. The intensity of TA-OSL increased with measurement temperature. The TA-OSL decay curves measured under both types of illumination can be described by a sum of two exponential components. Further, the TA-OSL stimulated by blue light is more intense than that corresponding to infrared light. The TA-OSL is consistent with the presence of at least two types of deep electron traps with differing values of the activation energy for thermal assistance. As regards dose response, the TA-OSL intensity increases sublinearly with dose between 100 and 1000 Gy.


Processes related to phototransfer under blue- and green-light illumination in annealed Al2O3:C,Mg

M.L. Chithambo, J.M. Kalita, N.M. Trindade

Journal of Applied Physics , vol: 131 , 245101 , 2022 , https://doi.org/10.1063/5.0094547

Abstract:

Phototransferred thermoluminescence (PTTL) of Al2O3:C,Mg induced by 470 nm blue, 525 nm green, and 870 nm infrared light is reported. Although its conventional TL glow curve measured during heating to 600 °C has seven peaks (labeled I–VII), only peak II is reproduced under phototransfer, except when the sample is preheated to 180 °C when peak IV also re-appears. The dependence of PTTL intensity on the duration of illumination for both PTTL peaks is analyzed using phenomenological and kinetic models as systems of acceptor and donors, with the number of the latter determined by experiment. The intensity of PTTL increases with the temperature of illumination with an activation energy of thermal assistance of either 0.015 ± 0.002 or 0.047 ± 0.002 eV when either 470 or 525 nm light is used but decreases at elevated temperatures with an activation energy of thermal quenching equal to 0.51 ± 0.02 eV independent of illumination wavelength. The long term behavior of time-response profiles for a system of one acceptor and a single donor, as an exemplar, as studied by stability theory, shows an unstable critical point. Mechanisms for the PTTL are discussed and the emission is ascribed to electron centers in the oxygen sub-lattice.


Concerning a hole trap in α-Al2O3:C,Mg

J.M. Kalita, M.L. Chithambo

Journal of Applied Physics , vol: 132 , 015103, 2022 , https://doi.org/10.1063/5.0092064

Abstract:

We report the existence of a hole trap in α-Al2O3:C,Mg as determined using thermoluminescence (TL) and optically stimulated luminescence (OSL). The associated experiments are based on the hypotheses that if a TL glow peak is associated with a hole trap in the glow curve of α-Al2O3:C,Mg, that hole trap will not participate in any light-induced electron-transfer process and its removal will not cause the OSL intensity to decrease. To examine the first hypothesis, a TL glow curve was recorded at 1 °C/s to establish the position of glow peaks. There is a high intensity peak at 184 °C (labeled as peak IV) and eight secondary peaks at 48, 80, 108, 228, 288, 320, 386, and 426 °C (peaks I, II, III, and V–IX). The light-induced charge transfer between various electron traps associated with the peaks was studied. This study reveals that all peaks except the one at 228 °C (peak V) participate in the charge-transfer process. A test of the second hypothesis shows that peak V is also not reproduced by illumination (phototransfer), and the depletion of this peak does not influence the charge-transfer process. An additional study on the effect of temperature on the TL and OSL intensity was carried out to further assess the nature of the charge traps associated with the peaks. The depletion of peak V does not affect the OSL intensity. The results from both experiments are clear evidence consistent with the hypothesis that the charge trap associated with peak V is a hole trap.