000382   MA J, ZHOU Y, SU J, SONG L, DONG Z, QI Z (Hebei Univ of Science and Technology, Shijiazhuang- 050 018, China, Email: sujia-2005@hotmail.com) : Enhancing traffic capacity of two-layer networks by link deletion. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02074-w.

Two-layer or multilayer networks can more accurately reveal the transmission dynamics of the actual network and increase the traffic capacity. Therefore, we considered optimising the physical layer topology of the twolayer network, and proposed a link deletion strategy at the physical layer. The nodes with maximum weight (ki*k j) were deleted, where ki and k j are the degrees of nodes i and j, respectively, and the traffic load was redistributed from the central node to the non-central nodes. The simulation results showed that the strategy significantly increased the network traffic capacity. In two-layer network model, the logical layer network structure is unchanged and the shortest path routing strategy is used.

10 illus, 43 ref

000381   WU C, WU C (China Univ of Mining and Technology, Xuzhou- 221 116, People’s Republic of China, Email: chengjinwu@cumt.edu.cn) : Recovery and enhancement of unknown aperiodic binary signal by adaptive aperiodic stochastic resonance. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02072-y.

In this study, the system with fractional power nonlinearity is introduced into the theory of aperiodic stochastic resonance (ASR). The fractional exponent is a key parameter and its effect on the ASR phenomenon excited by aperiodic binary signal is investigated in this system. Compared to the classical bistable system, the system with fractional power nonlinearity shows better performance. It can adjust not only the noise intensity but also the fractional exponent to enhance weak signal. In the field of signal transmission, pure aperiodic binary signal is usually submerged in the noise and the signal is unknown. Thus, an effective method is proposed based on ASR and moving average. By the method, the unknown aperiodic binary signal can be recovered in the noise background. To improve the efficiency of the signal recovery, the adaptive ASR is realised with the help of adaptive particle swarm optimisation (APSO) algorithm to optimise the parameters. The method may provide some reference to the engineering field.

9 illus, 1 table, 34 ref

000380   ANH N T, THANH T D, BANG N H, DONG H M (Ho Chi Minh City Univ of Food Industry, Ho Chi Minh City, Vietnam, Email: dong.gtvtmt@gmail.com) : Microwave-assisted all-optical switching in a four-level atomic system. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02068-8.

We study the all-optical switching of the weak probe field via a four-level atom system with the help of a microwave field and electromagnetically induced transparency effect. Here, the microwave field is used for coupling two-folded lower levels to which double dark resonances (DDRs) can arise. The atomic medium is switched from transparent to complete absorption under the DDRs. It is shown that the absorption spectrum, pulse propagations and all-optical switching dynamics of the probe field are dependent on the intensity of the microwave field, applied fields and probe detuning. Furthermore, the switching mode between the probe field and the microwave field can be antisynchronous or synchronous, depending on the probe detuning being adjusted to be equal to zero or ± c, respectively. Our results possibly are helpful in actual tests to design all-optical switching and optical storage devices in optical communications and signal processing.

7 illus, 36 ref

000379   AHMADI R, NAMI S (Tabriz Univ, Tabriz, Iran, Email: S.Nami@tabrizu.ac.ir) : Investigation of entanglement entropy in cyclic bipartite graphs using computer software. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02041-5.

We investigate the entanglement of the ground state in the quantum cyclic graphs whose nodes are considered as quantum harmonic oscillators. To this end, the Schmidt numbers and entanglement entropy between two arbitrary partitions with equal nodes of a cyclic graphs, are calculated. For that, the local operation is used to build singular value decomposition of potential matrix of cyclic graphs. Then the maximum value of entanglement entropy among all bipartite cyclic graphs is obtained.

21 ref

000378   SINGH T P (Tata Institute of Fundamental Research, Mumbai- 400 005, Email: tpsingh@tifr.res.in) : Quantum gravity, minimum length and holography. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02052-2.

The Karolyhazy uncertainty relation states that if a device is used to measure a length l, there will be a minimum uncertainty δl in the measurement, given by (δl)3 ∼ L2 Pl. This is a consequence of combining the principles of quantum mechanics and general relativity. In this letter we show how this relation arises in our approach to quantum gravity, in a bottom-up fashion, from the matrix dynamics of atoms of space–time–matter. We use this relation to define a space–time–matter (STM) foam at the Planck scale, and to argue that our theory is holographic. By coarse graining over time-scales larger than Planck time, one obtains the laws of quantum gravity. Quantum gravity is not a Planck scale phenomenon; rather it comes into play whenever classical space–time background is not available to describe a quantum system. Space–time and classical general relativity arise from spontaneous localisation in a highly entangled quantum gravitational system. The Karolyhazy relation continues to hold in the emergent theory. An experimental confirmation of this relation will constitute a definitive test of the quantum nature of gravity.

19 ref

000376   GAHLAWAT J, DAHIYA S (Physics Dep, Baba Mastnath Univ, Rohtak-124 021, Email: jgahlawat.bmu@gmail.com) : Parametric amplification and dispersion characteristics of optical phonon mode in a semiconductor magnetoplasma. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02063-z.

Using the classical hydrodynamic model of semiconductor plasmas, the parametric amplification and dispersion characteristics of optical phonon mode in a semiconductor magnetoplasma are investigated analytically. An expression for effective complex second-order optical susceptibility (χ(2) e = (χ(2) e )r + i(χ(2) e )i) is obtained under off-resonant laser irradiation. The analysis deals with qualitative behaviour of threshold pump amplitude (ξ0,th) for the onset of parametric excitation, anomalous parametric dispersion (via (χ(2) e )r) and parametric gain coefficient (gpara via (χ(2) e )i) with respect to externally applied magnetostatic field (B0) for different values of doping concentration (n0). Numerical estimates are made for n-InSb–CO2 laser system at 77 K. The analysis offers three achievable resonance conditions at which ξ0,th reduces whereas gpara enhances by two orders of magnitude. The lowering in ξ0,th and enhancement in gpara, under proper selection of B0 and n0, confirms the chosen nonlinear medium as a potential candidate material for the fabrication of efficient optical parametric amplifiers. The negative and positive enhanced parametric dispersion may be of potential use in the study of squeezed state generation as well as in group velocity dispersion in semiconductor magnetoplasmas.

6 illus, 34 ref

000374   RODRIGUES C G, LUZZI R (Pontifical Catholic Univ of Goiás, CP 86, Brazil, Email: cloves@pucgoias.edu.br) : Nonlinear charge transport in highly polar semiconductors: GaN, AlN, InN and GaAs. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02077-1.

In this paper, we present a collection of results focussing on the transport properties of doped direct-gap inverted-band highly polar III-nitride semiconductors (GaN, AlN, InN) and GaAs in the transient and steady state, calculated by using nonlinear quantum kinetic theory based on a non-equilibrium statistical ensemble formalism (NESEF). In the present paper, these results are compared with calculations using Monte Carlo modelling simulations and experimental measurements. Both n-type and p-type materials, in the presence of intermediate to high electric fields, are considered for several temperatures and carrier concentrations. The agreement between the results obtained using nonlinear quantum kinetic theory, with those of Monte Carlo calculations and experimental data is remarkably good, thus satisfactorily validating the NESEF.

34 illus, 3 tables, 161 ref

000373   PRADHAN J K, PRATAP D, RAMAKRISHNA S A (Physics Dep, Indian Institute of Technology, Kanpur- 208 016, Email: jkpradhan99@gmail.com) : Thin nanoporous anodic alumina film on aluminium for passive radiative cooling. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02076-2.

We demonstrate a simple, low-cost, and passive radiative cooler based on a monolithic design consisting of thin nanoporous anodic alumina (NAA) films grown on aluminium sheets. The NAA/Al structure maintains a high broadband reflectivity close to 98 % within the solar spectrum (0.4–2.2 μm) and simultaneously exhibits a high average emissivity of 88 % within the atmospheric infrared (IR) transmission window of 8–13μm with the peak IR emission approaching 99% at a wavelength of 10 μm. Optical modelling of the system using optical parameters of the materials confirms that the high solar reflectance arises due to the transparent nature of NAA and high reflectivity of bottom Al, while the large thermal IR emissivity arises from the interference effects of the NAA film and the high absorption of IR light due to phonon resonances in alumina at wavelength larger than 10 μm. Further, we estimate the average cooling power of NAA/Al to be about 136 W m−2 at ambient temperature even after including the contribution to heat input from external non-radiative processes. This robust and lightweight NAA/Al can be projected as an excellent alternative to optical solar reflectors used in spacecraft for thermal heat management and rooftop cooling green technologies.

6 illus, 36 ref

000372   CHAWLA J K (Physics Dep, Govt. Girls Coll Banswara, Banswara- 307 001, Email: jitendra123chawla@yahoo.co.in) : Effect of non-thermal electrons on ion-acoustic dressed solitons in unmagnetised plasmas. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02084-2.

Nonlinear propagation of an ion-acoustic dressed soliton is studied in unmagnetised plasma consisting of ion, positron and non-thermal electron. The exact soliton solution is derived using the reductive perturbation method (RPM) with the help of renormalisation procedure. This exact solution reduces to the dressed soliton solution when Mach number is expanded in terms of soliton velocity. The effects of non-thermal electrons, soliton velocity and Mach number on the characteristics (amplitude, width and product of amplitude and square of width) of the KdV soliton, core structure, dressed soliton and exact soliton are discussed in detail.

4 illus, 36 ref

000371   ZHANG Y, ZHOU P, YAO Z, MA J (Physics Dep, Lanzhou Univ of Technology, Lanzhou- 730 050, China, Email: hyperchaos@lut.edu.cn) : Resonance synchronisation between memristive oscillators and network without variable coupling. Pramana- J Phys 2021, 95(1), 10.1007/s12043-020-02073-x.

Continuous energy pumping and exchange along the coupling channel can balance the energy release between nonlinear oscillators for reaching complete synchronisation. When external stimulus is applied, energy is injected and encoded for regulating the dynamics of nonlinear oscillators and circuits. In this paper, the synchronisation between memristive Rössler oscillators is investigated by reactivating one memristive variable, and external stimuli are changed to detect the occurrence of synchronisation without direct variable coupling. In the presence of periodical stimulus, stochastic switch and feedback on the memristive variable can induce synchronisation between two memristive oscillators and chain network composed of memristive oscillators. In the presence of noise, stochastic feedback and disturbance on the memristive variable can keep synchronisation stable between two oscillators, and complete synchronisation is realised. In addition, the synchronisation factor and spatial patterns are calculated to confirm the occurrence of synchronisation between more chaotic oscillators when memristive function is activated even when no coupling channels are switched on.

10 illus, 51 ref

000370   ROY S, JAISWAL S, CHATTERJEE S, SEN A, DAS S, GHOSH S K, RAHA S, LYSAN V M, KEKELIDZE G D, MYALKOVSKY V V, BISWAS S (Physics Dep, Bose Institute, Kolkata- 700 091, Email: saikat@jcbose.ac.in,) : Stability study and time resolution measurement of straw tube detectors. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02094-0.

Straw tube detectors are single wire proportional counters that are widely used as tracking devices. We have carried out R&D activity with a straw tube detector prototype. The aim of this work is to study the stability of the performance in terms of gain and energy resolution of these types of detectors under high rate of radiation. The gain and energy resolution of the detector are studied along with its variation with ambient temperature and pressure. X-rays from a radioactive source are used to irradiate the detector and to monitor the energy spectra simultaneously for calculating the gain. The method followed here is unique as the ageing measurements have been performed without using an accelerated particle beam or any radiation generator. The performance of a straw tube detector has been studied in a laboratory for more than 800 h at a stretch using a single sealed radioactive X-ray source with high intensity. Variation of gain and energy resolution of the straw tube detector under X-ray irradiation in Ar/CO2 gas mixture (volume ratio 80/20) is discussed in this article. The gain of an aged straw depends on gas flow rate. We have estimated the time required for the gain of a straw tube detector under ageing tests to recover on increasing the gas flow rate. We have also estimated the time resolution of the straw tube detectors by using cosmic rays as the trigger for the Ar/CO2 gas mixture in 70/30 volume ratio (different gas mixture was used for the measurement of the time resolution). This type of ageing and time resolution measurements in Ar/CO2 gas mixture has not been reported earlier. The details of the measurement process and the experimental results are presented in this article.

14 illus, 23 ref

000368   MISHRA P, ACHARYA M R, PANDA S (Physics Dep, Odisha Univ of Agriculture and Technology, Bhubaneswar- 751 003, Email: satyanand@nitc.ac.in) : Mixed convection MHD nanofluid flow over a wedge with temperature-dependent heat source. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02087-z.

The present work investigates the transfer of heat, mass and fluid flow at the boundary layer of a nanofluid past a wedge in the presence of a variable magnetic field, temperature-dependent heat source and chemical reaction. The study is entirely theoretical and the proposed model describes the influence of Brownian motion and thermophoresis in the case of nanofluids. This study also includes the impact of thermal radiation. The partial differential equations relating to the flow are nonlinear and hence are numerically solved after transforming them into ordinary differential equations with similar variables. The outcome of the present study is given in tabular form and depicted graphically. It is found that the nanofluid flow along the wedge is accelerated by enhancing the Falkner–Skan parameter. The study further reveals that the magnetic field has an improved effect on the velocity. The Brownian motion parameter raises the profile of temperature but decreases the profile of volume fractions. Thermal radiation decreases the energy transport rate to the fluid and hence reduces the degree of heat present in the fluid. It is also observed that heat sink blankets the surface with a layer of cold fluid.

16 illus, 2 tables, 31 ref

000367   GUPTA N, KUMAR S (Physics Dep, Lovely Professional Univ, Phagwara- 144 001, Email: naveens222@rediffmail.com) : Self-action effects of quadruple-Gaussian laser beams in collisional plasmas and their resemblance to Kepler’s central force problem. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02079-z.

This paper presents theoretical investigation on the self-action effects of intense laser beams propagating through collisional plasmas. Particularly, the phenomena of self-focussing, self-trapping and self-phase modulation of the laser beam have been investigated in detail. In order to see the effect of uniformity as well as non-uniformity of the irradiance over the cross-section of the laser beam on its propagation characteristics field distribution in the medium has been expressed in terms of quadruple Gaussian (QG) profile instead of Gaussian profile. Following the moment theory approach, the nonlinear partial differential equation for the slowly varying envelope of the laser beam has been reduced to a set of coupled ordinary differential equations for the evolution of beam width and longitudinal phase. The equations so obtained have been solved numerically to envision the effect of laser as well as medium parameters on the propagation characteristics of the laser beam.

16 illus, 40 ref

000366   GOSWAMI J, SARKAR J, CHANDRA S, GHOSH B (Physics Dep, Jadavpur Univ, Kolkata- 700 032, Email: swarniv147@gmail.com) : Amplitude-modulated electron-acoustic waves with bipolar ions and kappa-distributed positrons and warm electrons. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02085-1.

In this paper, we have meticulously studied the amplitude modulation of electron-acoustic waves and the formation and properties of envelope solitons in a five-component complex plasma containing statistically kappadistributed warm and cold electrons, kappa-distributed positrons and Boltzmann-distributed positive and negative ions. The picture considered here is very similar to solar atmosphere and planetary environments. The parametric dependence of modulational instability on kappa index, positron and electron densities, ion and reciprocal of positron temperatures has been studied in detail and the findings obtained here will be beneficial for further astrophysical investigations.

22 illus, 36 ref

000365   SOLTANI H, SOHBATZADEH F, ZAKERI-KHATIR H (Atomic and Molecular Physics Dep, Mazandaran Univ, Islamic Republic of Iran, Email: hamedsoltani1991@gmail.com) : Numerical simulation of microplasma field-effect transistor at low voltages. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02092-2.

In this study, two-dimensional simulation of the microplasma field-effect transistor (MOPFET) was performed using COMSOL Multiphysics along with BOLSIG+ software and LXCat database. At first, argon plasma generation in the electric discharge channel was investigated in the case of an RF-biased drain terminal. The Townsend criterion for self-sustaining discharge was modified by including ion-enhanced secondary ionisation concerning to the micrometer scale of the discharge gap. The simulation results showed that the level of the gate electrode voltage serves as a tuner for the MOPFET current, and it changes the gas breakdown voltage. The results of the 2D simulation showed that the polarity of the gate voltage is crucial for controlling the MOPFET current and the operation of switching circuitry. To increase current, a new gas mixture was proposed and simulated. The IDS−VDS characteristic of the MOPFET was obtained with Ar/Hg (98:2). Static transconductance and hFE of the MOPFET were also evaluated. The results of this study can be used for designing and operating the MOPFET in an electronic circuit.

12 illus, 3 tables, 18 ref

000364   LEIVA C, ROMERO S ( de Física Dep, de Tarapacá Univ, Arica, Chile, Email: cleivas62@gmail.com) : Realisation of snyder operators in quantum mechanics. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02099-9.

The lack of experimental results of theories concerning the ultimate space/space–time structure, leads one to think about some simple experiments that can help demonstrate the main prediction: Space–time is discrete. In this paper, an implementation of Snyder operators is applied to simple geometries, to demonstrate that the spectrum of the position operator, in standard quantum mechanics (QM), is discrete when a parameter measuring the non-commutativity of quantum operators is introduced. The geometries are specially suitable for experiments in search of the behaviour of ultracold neutrons falling in the Earth’s gravitational potential.

16 ref

000362   MUNDRA R, CHATTOPADHYAY S, CHAKRABARTY I, GANGULY N (International Institute of Information Technology-Hyderabad, Gachibowli- 500 032, Email: rm29031996@gmail.com) : Broadcasting of NPT entanglement in two qutrit systems. Pramana- J Phys 2021, 95(1), 10.1007/s12043-021-02098-w.

It is known that beyond 2 ⊗ 2 and 2 ⊗ 3 dimensional quantum systems, Peres–Hordecki criterion is no longer sufficient as an entanglement detection criterion as there are entangled states with both positive and negative partial transpose (PPT and NPT). Further, it is also true that all PPT entangled states are bound entangled states. However, in the class of NPT states, there exist bound entangled states as well as free entangled states. All free/useful/distillable entanglements are part of the class of NPT entangled states. In this article, we ask the question that given an NPT entangled state in 3 ⊗ 3 dimensional system as a resource, how much entanglement can we broadcast so that resource still remains NPT. We have chosen 3 ⊗ 3 system as a first step to understand broadcasting of NPT states in higher dimensional systems. In particular, we find out the range of broadcasting of NPT entanglement for two-parameter class of states (TPCS) and isotropic states (IS). Interestingly, as a derivative of this process we are also able to locate the existence of absolute PPT (ABPPT) states in 3⊗3 dimensional system. Here we implement the strategy of broadcasting through approximate cloning operations.

2 illus, 1 table, 40 ref

000361   BELLI A, CHEREF O, RACHED H, CAID M, GUERMIT Y, RACHED D, RABAH M, ABIDRI B, KHENATA R (Djillali Liabès de Sidi Bel-Abbès Univ, Sidi Bel-Abbès, Algeria, Email: rachdj@yahoo.fr) : Electronic, optical, magnetic and thermoelectric properties of CsNiO₂ and CsCuO₂: Insights from DFT-based computer simulation. Pramana– J Phys 2021, 95(1), 10.1007/s12043-021-02088-y.

In this paper, we present the results of a detailed computational study of the structural, electronic, optical, magnetic and thermoelectric properties of the CsNiO2 and CsCuO2 Heusler alloys, by using the full potential-linearised augmented plane wave (FP-LAPW) method. The calculated structural parameters of the title compounds are in excellent agreement with the available theoretical data. The equilibrium ground-state properties were calculated and it was showed that the studied compounds are energetically stable in the AlCu2Mn phase within the ferromagnetic state. In order to evaluate the stability of our compounds, the cohesion energies and formation energies have been evaluated. The optoelectronic and magnetic properties revealed that these compounds exhibit half-metallic ferromagnetic behaviour with large semiconductor and half-metallic gaps. This behaviour is confirmed by the integer values of total magnetic moments, but these compounds do not satisfy the Slater–Pauling rule. Furthermore, the thermoelectric parameters are computed in a large temperature range of 300–800 K to explore the potential of these compounds for high-performance technological applications.

8 illus, 2 tables, 50 ref

000555   PALANIMURUGAN, JEYAVIJAYAN S (Physics Dep, Kalasalingam Academy of Research and Education, Krishnankoil- 626 126, Email: sjeyavijayan@gmail.com ) : Vibrational spectroscopic investigation and electronic properties of 4-hydroxy-3- methylbenzoic acid. Rasayan J Chem 2021, 14(1), 389-96.

The vibrational spectra for 4-hydroxy-3-methylbenzoic acid (HMBA) were recorded using FT-Raman (3600–100 cm^-1) as well as FTIR (4000-400 cm^-1) spectroscopies and the assignment of normal modes of the molecule was subsequently established by total energy distributions (TEDs). The density functional theory (DFT) calculations have been performed and compared through the wavenumbers of the observed results. The slight changes among the observed and computed wavenumbers indicate the ability of the computational method used in this study. The HOMO-LUMO charge-transfer interactions of the molecule which are the key factor for biological activity have been discussed. Further, the electronic properties of the molecule have been examined by Mulliken’s charge and molecular electrostatic potential (MEP) studies.

6 illus, 2 tables, 22 ref

000514   SEBAYANG K, RAHAYU S U, LEE M-W, GEA S, GINTING H, WARMAN A (Physics Dep, Sumatera Utara Univ, Medan- 20155, Indonesia, Email: siti.utari@usu.ac.id) : The comparison of opaque Tio₂ and transparent Tio₂ on the performance of AgSbS₂–sensitized solar cell prepared by solution processing. Rasayan J Chem 2021, 14(1), 88-93.

This study reported the investigation of the use of opaque and transparent TiO₂ paste as metal oxide on AgSbS₂ quantum dots (QDs)-sensitized solar cell. Doctor blade method was employed to coat TiO₂ paste onto FTO glass, whereas successive ionic layer adsorption and reaction (SILAR) was applied to grow AgSbS₂ into the TiO₂ layer. The SILAR process consisted of 3 cycles for depositing Ag-S and 6 cycles for obtaining Sb-S. AgSbS₂ was yielded after annealing process at 350 ⁰C for 10 minutes under nitrogen condition. The best photovoltaic performance was achieved from transparent TiO₂ paste, which gave the efficiency of 0.317 % with Voc of 0.24 V, Jsc of 3.51 mA/cm² , and FF of 37.62 %. Opaque TiO₂ paste showed lower photovoltaic performance, which gave an efficiency of 0.110 % due to the difficulty of electrolyte to penetrate the matrix of the TiO₂ layer and the existence of the cracks at the TiO₂ layer. These results showed that in the case of AgSbS₂ semiconductor, the utilization of transparent TiO₂ paste would give better photovoltaic performance than that of opaque TiO₂ paste.

4 illus, 1 table, 21 ref

000512   JEYASEELI P, JEYAMANGALAM F, SELVARAJ S, DURAI S C V (Physics Dep, Sarah Tucker Coll, Tirunelveli- 627 007, Email: jeyaseeli.rkr@gmail.com) : Conductivity and particle size measurement in sandy loam soil using organic amendment. Rasayan J Chem 2021, 14(1), 74-81.

An analysis of field study was undertaken at Karisalpatti in Cheranmahadevi block, Tirunelveli district of Tamil Nadu, South India in 2018 and the conductivity measurement was done for the sandy loam soil which is situated at 8.600 latitudes and 77.580 longitudes. The analysis was highly focused on the soil by blending vermin compost (VC) at 17.5 t ha^-1 concentration and also farmyard manure (FYM), vermin compost (VC) and Goat Manure (GM) at 17.5 t ha^-1 concentration. Before and after harvest the conductivity properties such as Electrical Conductivity (EC), Thermal Conductivity (K) and Hydraulic Conductivity (HC) were studied. The observed conductivities reveal the presence of soil moisture capacity. The moisture content in the soil can conduct an electric current. The morphological appearance such as the shape and size of the sandy loam soil was studied using SEM characterization. From the EDAX spectrum, the mineral composition of organic matter was confirmed. Particle size analysis of the sandy loam soil reveals the intensity distribution of soil particles. The particle size study of soil structure was essential to predict the water holding capacity of the soil. Method of combining manures with the composted organics could be taken up; so that the physical properties of the soil are enhanced. Organic agriculture enhances the physical potential of the soil, underground water resources and also protects them from natural and human-induced degradation. Monitoring the soil's physical properties influence precision farming in climatic change. The organic amendment added sandy loam soil increases the water permeability, total porosity and large pores in the soil which were responsible for gravitational water movement in the soil. Organic amendments improve the hydrologic effects on soil physical properties such as hydraulic conductivity and moisture content. Increasing residue returns and adding organic amendment improves the soil water holding capacity. It positively influenced the yield. Thus it is concluded that the application of organic amendment contributes high yield attributes to the corn crop.

9 illus, 2 tables, 24 ref

003036   THANGARASU S , SIVA V, BAHADUR S A, ATHIMOOLAM S (Physics Dep, Kalasalingam Academy of Research and Education, Krishnankoil - 626 126, Email: sthangarasu@gmail.com) : Structural, vibrational, quantum chemical calculations, thermal and antimicrobial studies on sulphate salt of 3-nitroaniline. Asian J. Chem 2021, 33 (1), 231 - 9.

In this work, bis(3-nitroanilinium) sulfate (3NASU) has been synthesized and crystallized successfully by solution growth combined with solvent evaporation technique. The studied salt, 3NASU molecular structure has been optimized with density functional theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311++G(d,p) basis set. The geometrical parameters of 3NASU have been analyzed. The computed vibrational spectra were compared with experimental result which show appreciable agreement. Thermal stability of the crystal was analyzed with TGA/DTA and the melting points of the salt identified at 210 ºC. HOMO-LUMO energy calculations have shown the charge transfer within the molecule. The possible pharmaceutical/biological activity of the salts confirmed by the frontier molecular orbital (FMO) analysis have lower band gap value. The antimicrobial activity of grown crystals were tested against certain potentially threatening microbes.

7 illus, 6 tables, 28 ref

003032   THANIGAIARASU V J, KANAGATHARA N, USHA R, SABARI V, NATARAJAN V (Physics Dep, Saveetha Institute of Medical and Technical Sciences, Thandalam - 602 105, Email: kanagathara23275@gmail.com) : Mechanical, thermal properties and hirshfeld surface analysis of N-acetylglycine single crystal. Asian J. Chem 2021, 33 (1), 203 - 9.

Mechanical properties of some amino acid based derivatives plays a versatile role in the device fabrication due to its mechanical strength. One such acetyl derivative of glycine named N-acetylglycine has been taken in the present study for investigation. Hardness analysis has been carried out on the grown crystal with various loads and it was observed that Vicker’s hardness number (Hv) varied for different loads. The work hardening coefficient is calculated to be 1.628 which confirms that the grown crystal comes under moderately hard material category. Other mechanical parameters like minimum load indentation (W), materials constant (k₁), load dependent constant (A₁) and elastic stiffness constant (C₁₁) have also been calculated. The thermal analysis has also been carried and it reveals that the complete weight loss of N-acetylglycine starts from 208.60 ºC and ends at 281.58 ºC. The corresponding DTA peak is observed at 217.97 ºC which is the melting point of the sample. As expected, there is no phase transition till the material melts and this enhances the temperature range for the utility of the crystal. Kinetic and thermodynamic parameters have been calculated. All the results obtained from hardness as well as thermal measurement confirm the material may be suitable for electro-optic device applications. Further, the 3D Hirshfeld surface analysis and 2D fingerprint maps gives deep insight into the intermolecular interactions between the compound.

8 illus, 52 ref

003031   RAO G V G, BABU S (Physics Dep, Koneru Lakshmaiah Education, Vaddeswaram - 522 502, Email: babu.computers@gmail.com) : Molecular Interactions of piperidinium based ionic liquids with water/alcohol at different temperatures. Asian J. Chem 2021, 33 (1), 195 - 202.

In this experimental investigation, the thermodynamic fundamental parameters of density (ρ) and speed of sound(U) were calibrated for aqueous solution/alcoholic (1-propanol and 2-propanol) solutions of piperidinium based ionic liquids of 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPiBF₄) in various concentrations within temperatures from 303.15 to 313.15 K. From these experimental determined values, various thermodynamic acoustic parameters of excess molar isentropic compressibility (K^E _s,_m), excess molar volume (V^E _m) are expressed in specific and non-specific molecular interactions. Moreover, calibration of the partial molar volume′s and partial isentropic compressibility′s of both components shows strong interaction in BMPiBF₄ + 2-proponol combination than any other executed binary composites. In addition to this, the FTIR characteristic spectrum of all combinations at different concentrations gives the more promising features such as interaction behaviour that helps our analysis to guide the interactions of individual bonds.

7 illus, 4 tables, 45 ref

003014   JEYAVIJAYAN S, MURUGAN P (Physics Dep, Kalasalingam Academy of Research and Education, Anand Nagar, Krishnankoil - 626 126, Email: sjeyavijayan@gmail.com) : Spectroscopic, electronic and optical properties of 4-nitroimidazole using DFT Calculations. Asian J. Chem 2021, 33 (1), 83 - 8.

Theoretical and experimental vibrational spectra of 4-nitroimidazole were studied by FTIR, FT-Raman spectroscopic techniques and density functional theory (DFT) method. The contributions of the different modes to each wavenumber were confirmed using total energy distribution (TED). The optimized parameters and thermodynamic properties of 4-nitroimidazole have been computed. The charge transfer interactions of the molecule were explained from the small value of HOMO-LUMO energy gap. The NBO analysis, Mulliken’s plot and MEP studies of the molecule have also been reported.

6 illus, 4 tables, 23 ref

045750   ASSEFA N A, BHARDWAJ M K (Physics Dep, Mekelle Univ, Ethiopia) : Measuring of radon concentration in indoor air in Adigudem, Tigray, Ethiopia. Int J Sci Nat 2020, 11(3), 48-51.

Radon measurements were carried out in 12 dwellings of Adigudem, Ethiopia using LR-115 type II Cellulose Nitrate films. After exposure time of 4 months, the detectors were etched in a NaOH solution at 65 °C. Obtained values show that concentrations of indoor radon vary from 53 Bq/m3 to 125Bq/m3 with mean value of 92.17Bq/m3 . In general, the level of radon concentration found to be within recommended limits.

2 illus, 1 table, 7 ref

044077   OTRYVANOV D (Coll of Economics and Management Nanjing Univ of Aeronautics and Astronautics, Nanjing, China) : Research on territorial structures of Taiwanese TNCs’ subsidiaries in electronic industry. Int J Multidiscip Res Dev 2020, 7(1), 76-82.

The objective of this paper is to investigate the factors influencing on territorial structures of Taiwanese transnational corporations (TNCs). The study used combined data of the largest Taiwanese TNCs from their annual reports alongside with Taiwan Statistical Databook. More than 800 subsidiaries were investigated and sorted by 4 major types: manufacturing, R&D, marketing and investing. Combining logarithmic gravity model with CAGE (cultural, administrative, geographic and economic) distance framework an empirical analysis was conducted. To reveal the territorial structure of Taiwanese subsidiaries the number of subsidiaries in the host country was chosen as a dependent variable. GDP of the host country and Taiwan alongside with the distance between them represented a gravity equation in the model. Macroregion dummy variables, language preference, difference in political stability were chosen as a representation of CAGE distance. GDP per capita and GDP annual growth rate were used as control variables. 7 cases for 4 types of subsidiaries and for 2 manufacturing types of TNCs in electronic industry and for total number of subsidiaries were analyzed. The research has shown the importance on dividing subsidiaries into their specialization types and defining macroregions where TNCs’ subsidiaries operate. These typologies help to understand the nature of territorial structure of TNCs’ abroad activity and reveal the differences among types of subsidiaries and manufacturing types of TNCs. However, I haven’t found high significance for distance impact for Taiwanese TNCs. Cultural similarity impacts not only FDI inflows, but also to the number of subsidiaries in the host country.

1 illus, 5 tables, 32 ref

044063   GUPTA AD, MISHRA A , MEHTA RK , GUPTA Y , PANDEY SK (Acharya Narendra Deva Univ of Agriculture and Technology, Ayodhya, Uttar Pradesh) : Experimental Investigation for photo-voltaic power generation using the concept of solar tree. Int J Multidiscip Res Dev 2020, 7(1), 01-4.

Solar energy is abundant in quantity and free of cost. Solar PV technology converts incoming radiation from Sun directly into electricity, which makes it one of the most promising renewable technologies available for sustainable development. However, it consumes a large amount of land, which can be used for other human activities. Solar PV tree is a novel technique used for Sunlight capture. It consists of PV panels fixed as leaves on a tree-like structure, and it reduces the land footprint of the PV system. In this study, the daily energy output of a 36 Watt solar system is maximized. For that, the flexible tree structure is designed. Energy output is maximized by varying the branch angle of the tree structure. Also, comparison of energy output for the standard layout and solar tree of 18 watt is done. The study showed that Solar Tree is a good alternative for the solar power generation instead of conventional layout of photovoltaic generation. Using Solar Tree we can reduce the land footprint area of solar power generation which can save land for other applications. The daily energy output from the Solar Tree can be increased as compared to the standard PV layout. Configuration I, defined in the study is found as optimum at which the energy output increased up to 59.11 %.

6 illus, 9 ref

042188   AGGARWAL B, ARORA Y, DHONA J K (Electronics and Communication Engineering Div, Netaji Subhas Univ of Technology, New Delhi - 110 078, Email: kbhawnagarg@yahoo.co.in) : Bandgap current reference using widlar current source. Indian J Eng Mater Sci 2020, 27(4), 934-8.

This paper has proposed a temperature insensitive current reference (CR) using Widlar current source. This CR has overwhelmed the direct relation of current to temperature present in Widlar current source. To obtain temperature insensitivity the proposed CR has been combined the complementary temperature behavior of current across MOSFET and BJT. Eldospice has supported the simulations of the proposed circuit using level 53, 0.18 µm CMOS technology with the help of EldoSpice. The proposed circuit has presented almost constant reference current of 63µA at a supply voltage of 1.8V for a temperature range of -30 to 100 °C. The proposed circuit has shown the maximum variation of 0.1µA as compared to 24.87µA in conventional Widlar current source.

5 illus, 2 tables, 15 ref

042187   KHAN I A, AGARWAL A (National Institute of Technology, Delhi - 110 040, Email: irfankhan@nitdelhi.ac.in) : Digitally controlled sigma-delta modulated direct matrix converter for high frequency AC-AC Conversion. Indian J Eng Mater Sci 2020, 27(4), 927-33.

In recent times, several digitally controlled modulation techniques (MTs) have envisioned for generating pulse width modulation (PWM) trigger pulses to improve the quality of the output (o/p) produced [in terms of reduced total harmonic distortion (THD)], from direct matrix converter (DMC). The development of a digital controller for single-phase DMC, producing o/p frequencies higher than the input frequency has been dealt with in this paper. Performance of the proposed DMC has been analysed by applying an advanced modulation technique, named as “Sigma-Delta modulation”. The complete system has been simulated on the MATLAB/SIMULINK platform as well as successfully implemented on the real-time digital simulator “OPAL-RT: OP4510”. Working of the proposed digital controller has been successfully verified for the DMC with o/p frequency, ranging from 100 Hz to 60 kHz. With the Sigma-Delta modulated trigger pulses, the lowest THD (associated with o/p voltage of the DMC) is found to be around 3.1 %. As the real-time results have been acquired in the close vicinity and conformity to the results achieved with simulations, this validates success of the proposed digital controller.

15 illus, 28 ref

046773   ABDOON R S, KHUDAIR Z A (Physics Dep, Babylon Univ, Hillah, Iraq, Email: sr614@ymail.com) : Isolating liver abnormalities in CT scan images using enhancement based technique. Med Legal Update 2020, 20(1), 10.37506/v20/i1/2020/mlu/194720.

One of the most dangerous diseases that causes death is liver cancer. As faster as detection of liver tumors and other abnormalities, as chances of survival will be increased. There are many modalities of medical scanning such as CT scan can be adopted for early detecting of the presence of any liver abnormality. In this study many CT scan liver images were adopted to investigate the robust performance of the proposed segmentation method. The proposed technique is an enhancement histogram based method employed here for segmentation purpose. The results of the presented technique showed the success of the technique in isolating and extracting the abnormal regions adequately. As well as, the implemented segmentation technique succeeded to extract the approximated whole liver regions according to the consultation of the radiologist. The processed technique was evaluated by calculating its accuracy to extract abnormal regions and it was 100 %, whereas for extracting the whole liver regions the accuracy was 90 %. In this study, the percent relative surface area of the abnormal regions were calculated as well.

4 illus, 1 table, 16 ref

042161   ZHUODA J (Jiujiang Univ, Jiujang 332005, China, Email: tengqinsl@163.com) : Enhancement of interfacial adhesion in UHMWPE fiber/HDPE composites by electrophoretic deposition of graphene oxide on UHMWPE fibers. Indian J Eng Mater Sci 2020, 27(3), 737-43.

In contrast to the conventional methods of improving interface and performances of UHMWPE fiber composites through fibre surface modification, this paper has reported a novel approach to deposit graphene oxide (GO) to increase the fiber/matrix interfacial shear strength (IFSS) of ultra high molecular weight polyethylene fibers (UHMWPE fiber) reinforced high density polyethylene (HDPE) composites. To validate our argument, GO has been synthesized and deposited over UHMWPE fiber through electrophoretic deposition. Tuned voltage lead to different thickness of deposited GO steadily increasing with the electric field up to 10 V/cm. Coated fibers have been aligned in a mold and an HDPE matrix has been used to create a single-fiber microcomposite. This latter has resulted to be muchhigher than the ILSS thus proving the efficiency of the new GO coating method here proposed for producing advanced graphene based composites. The failure of the composite at the GO/matrix rather than at the GO/UHMWPE fiber interface has been also confirmed by scanning electron microscopy observation of the fracture surfaces of microcomposites.

5 illus, 3 tables, 21 ref

042158   SILVA G, SOUZA D G B D, GABRIEL L C, RODRIGUES G, SILVA C E S D (Production Engineering and Management Dep, Federal Univ of Itajuba, Itajuba-MG, 37500 – 903, Brazil, Email: dalgarbor@gmail.com) : Processing parameters in the ball milling of niobium hydride: An optimization approach. Indian J Eng Mater Sci 2020, 27(3), 717-23.

Due to its particular properties, niobium has been widely used in the industry. In order to produce niobium-base parts, its powder can be obtained through a powder metallurgy’s method called ball milling. In this article, the ball milling parameters, in the production of niobium’s powder,have been optimized using the Taguchi’s method in order to obtain a high yield in the process, considering a particle size smaller than 75 m. Taguchi’s method, among several experimental designs, has been chosen due to its simplicity, efficiency and systematic approach to determine the optimal parameters in a manufacturing process. The experimental results have been indicated that the milling speed and time are the main variables in the process. In addition, the morphology of niobium hydride particles with the lowest and highest yield has been analyzed through the electron microscopy’s scanner.

5 illus, 5 tables, 21 ref

042149   JAYASEELAN C, PADMANABHAN P, ATHIJAYAMANI A, RAMANATHAN K (Mechanical Engineering Dep, Mohamed Sathak Engineering Coll, Kilakarai - 623 806, Tamilnadu, Email: cj_seelan@yahoo.co.in) : Effect of mechanical properties on banana macro particle reinforced epoxy composites. Indian J Eng Mater Sci 2020, 27(3), 643-8.

Mechanical properties of banana macro particles reinforced epoxy composites have been evaluated in this study. Composites have been prepared with 25, 30, and 35 wt % of banana macro particles using compression moulding machine. Mechanical properties (tensile, flexural, and impact) of banana macro particles reinforced epoxy composites have been obtained as a function of content of banana macro particles. The results show that the mechanical properties are found to increase substantially with increasing banana macro particles with epoxy composite. Composite with 35 wt% have the highest mechanical properties, i.e., the tensile strength of 24.36 MPa; the flexural strength of 67.16 MPa; the impact strength of 0.32 J. Scanning electron microscope analysis has shown the failure mechanism and the damaged behaviors occurred in the composites after tests.

10 illus, 1 table, 25 ref

042054   UGURLU G, BEYTUR M (Physics Dep, Kafkas Univ, 36100 Kars, Turkey, Email: gugurlu@kafkas.edu.tr) : Theoretical studies on the structural, vibrational, conformational analysis and nonlinear optic property of 4-(methoxycarbonyl)-phenylboronic acid. Indian J Chem Sec A 2020, 59A(10), 1504-12.

In this paper, the structural, electronic, non-linear optical (NLO) properties and vibrational frequencies of 4-(methoxycarbonyl)-phenylboronic acid have been examined theoretically using ab initio Hartree-Fock (HF) and Density Functional Theory (DFT/B3LYP) methods applying the standard 6-311++G(d,p) basis set. ¹H- and ¹³C NMR chemical shifts are calculated by employing the direct implementation of the gauge including-atomic-orbital (GIAO) method at the B3LYP/6-311++G(d,p) and HF/6-31G(d) levels of the theory. There are two conformers, cis-trans(ct) and trans-cis (tc) for title molecule. The energy difference between ct and tc conformers of studied molecule are of 0.126 kcal/mol with B3LYP/6-311++G(d,p) and 0.138 kcal/mol with HF/6-311++G(d,p), respectively. The conformer ct is more stable than the conformer tc. Also, the energy gap differences between the highest occupied and the lowest unoccupied molecular orbitals, dipole moment, polarizability and first static hyperpolarizability are calculated as a function of both dihedral angle (C3-C4-C7-O3), between methoxycarbonyl group (CH₃-O-CO-) and benzene ring, and dihedral angle (C2-C1-B-O1), between boronic acid group (-B(OH)₂) and benzene ring. In the change of the energy gap and polarizability depending on dihedral angles, it is shown that the polarizabilities follow inverse relationship the energy gaps.

7 illus, 4 tables, 48 ref

042040   MURUGAN E, ARUNACHALAM P, JEBARANJITHAM J N (Physical Chemistry Dep, Madras Univ, Chennai - 600 025, Tamil Nadu, Email: dr.e.murugan@gmail.com) : Efficient soluble and polymer cross linked insoluble poly-4-vinyl pyridine metal(V) chloride catalysts for esterification of butanol with acetic acid. Indian J Chem Sec A 2020, 59A(09), 1327-40.

New soluble and insoluble Ta, Mo and Sb pentachloride complex catalysts have been prepared using pyridine and polymer supported cross-linked (poly-4-vinyl pyridine) beads (PSCPVP), respectively. The prepared catalysts are characterized with FTIR, SEM, EDAX, CHN and TGA. The catalytic activities of these catalysts have been examined for esterification of acetic acid with butanol through gas chromatographic technique. The soluble complex catalyst show better activity than the insoluble catalyst, but it suffers from recovery and recyclability. The insoluble catalysts maintain stability up to three recycle times. From the k_obs values, it is found that all the soluble catalysts of Py-MCl₅, M=Ta, Mo & Sb (k_obs=7.26, 5.48 & 1.47×10³ min^-1) showed higher catalytic activity than the insoluble PSCPVP-MCl₅ (k_obs=5.18, 2.24 & 0.87 x10³ min^-1)_, but the latter catalysts are superior to the former in terms of recyclability. The catalytic activity of soluble Py-TaCl₅, Py-MoCl₅, Py-SbCl₅ catalyst is found to be 1.40, 2.44 and 1.68 times higher than PSCPVP-TaCl₅, PSCPVP-MoCl₅ and PSCPVP-SbCl₅, respectively. PSCPVP-TaCl₅ catalyst is found to be the superior most catalyst among the three catalysts. Further, these catalysts can be used in column batch reactors to conduct the reaction in continuous mode.

6 illus, 4 tables, 27 ref

042039   FU R, JIANG S (Northeast Electric Power Univ, Jilin province, 132011, China, Email: furao18604322849@sina.com) : Selective adsorption of bovine hemoglobin by Ni²⁺-functionalized silica nanoparticles. Indian J Chem Sec A 2020, 59A(09), 1321-6.

In this work, we have used Stöber method to prepare 200 nm SiO₂ particles and then immobilized metal affinity ligand iminodiacetic acid (IDA) and charged them with Ni²⁺ ions. The particles show high absorption efficiency to bovine hemoglobin and the maximum extraction amounts reached 43.4 mg/g. The particles have been applied to separate a model protein mixture of bovine hemoglobin (BHb) and bovine serum albumin (BSA). They can be separated and showed low non-specific adsorption. Then we have used these particles to extract BHb from the mixture of BHb and DNA. They have potential applications in removing abundant protein in proteomic analysis, and we hope it may become a simple, convenient, and potentially effective way to purify hemoglobin in serum.

11 illus, 31 ref

042036   RADHAKRISHNAN R (Theoretical Physics Dep, Madras Univ, Chennai - 600 025, Tamil Nadu, Email: rkrishna.tp@gmail.com) : Optoelectronic properties of all-Inorganic lead-free halide double perovskites (Rb_xCs_1-x)2AgBiBr₆ for solar cell applications. Indian J Chem Sec A 2020, 59A(09), 1298-304.

Solar cells based on lead-free double perovskites as absorber layer is an environment friendly, stable alternative for the conventional lead based hybrid halide perovskites. A comprehensive theoretical study on the optical and electronic properties of all-inorganic double perovskite with A₂BB’X₆ stoichiometry is done using density functional theory. Doping studies on (Rb_xCs_1-x )₂AgBiBr₆ perovskite is done using the virtual crystal approximation method within density functional theory. It is found that as increasing the Rb content (x) from 0.0 to 1.0 in Rb_xCs_1-xAgBiBr₆, the lattice parameter, dielectric constant and band gap are found to be decreasing linearly in accordance with Vegard's law. The lattice constant decreases linearly in x with a function of a(x) = 11.516 - 0.0057 x (Å), while the band gap decreases linearly as a function of x, E_g(x) = 1.472 - 0.0009 x (eV). Opto-electronic properties of substitutional doping of Rb in (Rb_xCs_1-x)₂AgBiBr₆ is compared with Cs₂AgBiX₆ (X=Cl, Br, I) and Br doped Cs₂AgIn(Br_xCl_1-x)₆.

6 illus, 2 tables, 46 ref

042034   MURUGAN E, SARANYA S, ASWINI A (Physical Chemistry Dep, Madras Univ, Chennai - 600 025, Tamil Nadu, Email: dr.e.murugan@gmail.com) : Modification of glassy carbon electrode with trigona carbon nanopetals/ferrocene/gold nanoparticles nanocomposite for electrochemical detection of dopamin. Indian J Chem Sec A 2020, 59A(09), 1285-91.

In this study, we have synthesized a composite using carbon material derived from bio-inspired onion peel morphology like 2D trigona carbon nano petals (TCP) incorporated with ferrocene (FC). The FC is added with the purpose of improving the electrochemical behaviour of TCP. Further, to increase the number of electrochemically active sites in the composite, gold nanoparticles (AuNPs) were again decorated on TCP/FC, and thus derived electrochemically active TCP/FC/AuNPs nanocomposite. We have characterized the properties and surface morphology of this nanocomposite through spectroscopic and microscopic techniques. Further, using this nanocomposite for surface modification of glassy carbon electrode, we have developed an efficient GCE-TCP/FC/AuNPs electrode. The electrochemical efficiency of this electrode has been inspected through sensing and quantification of pharmaceutically valuable biomolecule dopamine through CV, DPV and square wave voltammetry techniques. The observed CV results reveals that the newly designed GCE-TCP/FC/AuNPs electrode has an ability to detect the dopamine with wide linear range of concentration from 5.96 × 10^-6 to 0.1 × 10^-4 M and its limit of detection was 2.9 × 10^-6 M under 0.1 M phosphate buffer medium (pH 7.0). Therefore, it is important to mention here that this newly fabricated electrode can very well be used for real time sample analysis for sensing and detection of dopamine as it plays a key role in the neurotransmission and causes several diseases.

5 illus, 40 ref

042027   BANJARE R K, BANJARE M K, GHOSH K K, MUNDEJA P, PANDA S (MATS Univ, Pandari, Raipur (C.G.) - 492 009, Email: drmanojkb@matsuniversity.ac.in) : Interfacial and thermodynamic approach of surfactants with α-chymotrypsin and trypsin: A comparative study. Indian J Chem Sec A 2020, 59A(08), 1128-35.

This work deals with the interactions among cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) with α-chymotrypsin (α-CT) and trypsin in aqueous medium on pH 7.75 by conductivity and surface tension measurements. The critical micelle concentrations (CMC), surface parameters i.e., the maximum surface excess concentration (Γ_max), minimum area per surfactant molecule (A_min), the surface pressure at CMC (π_CMC) and thermodynamic parameters i.e., degree of ionization (α), Gibbs free energy of micellization (ΔG°_m), the standard Gibbs energy of adsorption (ΔG°_ads)_, the free energy at air-water interface (ΔG^s_mim) have been evaluated. The CMC has increased and surface tension of CMC (γ_CMC) values have decreased (at maximum μL of α-CT and trypsin), significantly in the presence of different μL of the added α-CT and trypsin. In this study, ΔG⁰_ads value is established to be greater than ΔG⁰_m, showing that adsorption is more favored in aqueous surfactants systems. Thermodynamic parameters show that enzyme-CTAB/SDS monomeric aggregation started to form micelles at a higher concentration of surfactant to compare with the CMC of pure CTAB/SDS micelles. It is significant that increasing the μL of α-CT and trypsin results in an increase in the spontaneity CMC on surfactants, α-CT and trypsin have more affinity for SDS compared to CTAB.

2 illus, 3 tables, 38 ref

042018   GSLAMOGLU F, ERDOGAN N (Chemistry Dep, Recep Tayyip Erdo?an Univ, 53100 Rize, Turkey, Email: fatih.islamoglu@erdogan.edu.tr) : Calculation of thermodynamic properties of the most important forty-seven different solvents to create an information data bank through semi-empirical quantum methods used in determination of theoretical pKa. Indian J Chem Sec A 2020, 59A(07), 962-74.

In this study, we have calculated the thermodynamic properties, especially in determining the theoretical acidic properties and pKa values of organic compounds, as enthalpy (ΔH, kcal/mol), heat capacity (C, cal/Kmol), entropy (ΔS, cal/Kmol), and free energy (ΔG, kcal/mol) of 47 different solvents with the MOPAC 2016 computer program at 298 K used in semi-empirical quantum methods (PM7, PM6, PM6-DH2, RM1, PM3, AM1, and MNDO). Evaluations are made between these values and the used methods. At the same time, a data bank is created with obtained values for the researchers who will do scientific study for the theoretical pKa.

5 illus, 8 tables, 19 ref

042017   JEEVITHA D, SADASIVAM K, PRAVEENA R (Physics Dep, Bannari Amman Institute of Technology (Autonomous), Sathyamangalam, Tamil Nadu - 638 401, Email: dftsada@gmail.com) : DFT investigation of pachypodol for exploring anti-oxidant action – Performance of B3LYP and M06-2X. Indian J Chem Sec A 2020, 59A(07), 952-61.

Anti-oxidant mechanism of the pachypodol is computed with the aid of density functional theory (DFT) in the light of B3LYP (B3, Lee-Yang-Parr correlation function) and M06-2X (highly parameterized, exchange correlation function) using 6-311G(d,p) basis set in the Gaussian 09 software package. This investigation aims to prove the better reaction enthalpies among hydrogen atom transfer (HAT), sequential proton-loss electron-transfer (SPLET) and single electron transfer-proton transfer (SET-PT) in gas and solvent phases with both the level of theories (B3LYP and M06-2X). The result shows that the preferred anti-oxidant mechanism is found to be HAT in both gas and solvent phases. The analysis of bond dissociation enthalpy (BDE) has been carried out in gas and solvent phases. Molecular descriptors are analyzed and computed in the light of both the level of theories. The radical scavenging of pachypodol is well established with B3LYP theory, since it yields appreciable results with respect to BDE, IP and PDE than M06-2X level of theory. Fukui function of the compound is performed using both the level of theories and preferred electrophilic and nucleophilic sites of pachypodol are analyzed. The weak and strong intramolecular bonds are examined with the aid of NBO.

3 illus, 7 tables, 36 ref

042005   PATIL D V, PATIL V S (Chemistry Dep, Krishna Mahavidyalaya, Bk - 415 108, Maharashtra, Email: dtp.phy@gmail.com) : Fluorescence resonance energy transfer from pyrene nanoparticles to riboflavin: Spectroscopic insights and analytical application. Indian J Chem Sec A 2020, 59A(06), 783-9.

The aqueous suspension of fluorescent pyrene nanoparticles (PyNPs) have been prepared by a reprecipitation method in the presence of sodium dodecyl sulphate (SDS) as a stabilizer. The PyNPs shows bathochromically shifted aggregation induced enhanced emission in the spectral region 400 nm to 600 nm peaking at 466 nm where Riboflavin (RF) absorbs strongly. The systematic fluorescence resonance energy transfer (FRET) experiments performed by measuring fluorescence quenching of PyNPs with successive addition of RF analyte has exploited the use of PyNPs as nano probe for detection of RF in aqueous solution with lower limit of detection 10.163 × 10^-5 mol.L^-1. The fluorescence of PyNPs is quenched by RF and quenching is in accordance with the Stern-Volmer relation. The distance r between the donor (PyNPs) and acceptor (RF) molecules has been obtained according to the FRET method. The evaluation of photo kinetic and thermodynamic parameters such as quenching rate constant (k_q), enthalpy change (ΔH), Gibbs free energy change (ΔG) and entropy change (ΔS) are calculated by quenching results obtained at different constant temperatures. The proposed FRET method based on fluorescence quenching of PyNPs is used further to develop an analytical relation for estimation of RF from pharmaceutical samples available commercially in the market.

9 illus, 4 tables, 36 ref

041996   MANHAS U, SHARMA N D, SINGH D (Chemistry Dep, Jammu Univ, Jammu - 180 006, Email: drdssambyal@rediffmail.com) : Synthesis, structural and physical properties of some rare-earth doped nickel chromites. Indian J Chem Sec A 2020, 59A(05), 633-9.

A systematic investigation of structural, magnetic and transport properties of NiCr_1.9R_0.1O₄ (R = Eu, Dy and Ho) has been undertaken. Rietveld analysis of powder X-ray diffraction data revealed that all the compounds crystallize in the cubic symmetry with Fd^-₃m space group having small volume fraction of orthorhombic phase RCrO₃. Both lattice parameter and cell volume decreases with the substitution of heavier rare earth ion which is consistent with the decrease in ionic radius of rare earth ion. The temperature dependent magnetization studies have shown that all our investigated compounds have negative value of Weiss constant. It indicates the dominance of anti-ferromagnetic interactions in the samples. The phases are semi-conductors and the conduction mechanism is dominated by Arrhenius model in the high temperature paramagnetic semiconducting region.

7 illus, 5 tables, 34 ref

041931   ASMI H, BENTAYEB F, BOUZEKRAOUI Y, BONUTTI F (Physics Dep, Mohammed V Univ, Rabat, Morocco, Email: youssef0fsr@gmail.com) : Optimization of scatter correction method in samarium-153 single-photon emission computed tomography using triple-energy window: A monte carlo simulation study. Indian J Nucl Med 2020, 35(3), 210-5.

In single-photon emission computed tomography imaging, the presence of scatter degrades image quality. The goal of this study is to optimize the main- and sub-energy windows for triple‑energy window (TEW) method using Monte Carlo  SImulating Medical Imaging Nuclear Detectors (SIMIND) code for samarium-153 (Sm-153) imaging. The comparison is based on the Monte Carlo simulation data with the results estimated using TEW method. Siemens Symbia gamma-camera equipped with low-energy high-resolution collimator was simulated for Sm-153 point source located in seven positions in water cylindrical phantom. Three different main-energy window widths (10 %, 15 %, and 20 %) and three different sub-energy window widths (2, 4, and 6 keV) were evaluated. We compared the true scatter fraction determined by SIMIND and scatter fraction estimated using TEW scatter correction method at each position. In order to evaluate the image quality, we used the full width at half maximum (FWHM) computed on the PSF and image contrast using Jaszczak phantom. The scatter fraction using TEW method is similar to the true scatter fraction for 20 % of the main-energy window and 6 keV sub-energy windows. For these windows, the results show that the resolution and contrast were improved. TEW method could be a useful scatter correction method to remove the scatter event in the image for Sm-153 imaging.

7 illus, 5 tables, 27 ref

046729   ALI R M, ABBAS N K, ABBAS A K, ABBAS L K (Physics Dep, Baghdad Univ, Baghdad, Iraq) : Histological sections of pancreas and serum biochemical changes in rats after dexamethasone and zinc oxide nanoparticles injection. Med Legal Update 2020, 20(1), 10.37506/v20/i1/2020/mlu/194405.

Zinc Oxide Nanoparticles have been prepared using a simple green synthesis method by green tea extract (Camellia sinensis) as a reducing and capping agent, XRD measurement of Nano powder stated that Zinc Oxide had a hexagonal wurtzite structure, UV-Vis. The maximum absorption peak was approximately 318 nm and the energy gap was nearly 3.8eV calculated using Planck’s equation, blood serum sugar levels, liver function after ZnO NPs injection for rats was recorded. Forty-eight adult male rats were used and separated randomly into six groups of eight (n=8) rats in each group.Results stated that blood glucose levels, liver enzymes were increased in groups that injected by dexamethasone while considerably modified in rats administered by the first dose (100 mg/kg) of ZnO Nanoparticles while the other dose (300 mg/kg) hadn’t any significant effects.

3 illus, 2 tables, 26 ref

041660   BALLA A, GOLI D (Pharmaceutics Dep, Acharya & BM Reddy Coll of Pharmacy, Karnataka - 560 090, Email: anudeepballa@gmail.com) : Formulation & evaluation of PLGA nanoparticles of ropinirole HCl for targeting brain. Indian J Pharm Sci 2020, 82(4), 622-31.

The current research was aimed at formulating brain targeting polymeric nanoparticles of a hydrophilic anti-parkinson agent (Ropinirole HCl) to improve the drug passage to brain. Two different approaches were used for the study. One was Chitosan nanoparticles prepared by ionic gelation method using tripolyphosphate as cross-linking agent and the other one was poly (lactic-co-glycolic acid)50:50 monomer ratio poly D,L-lactic-co-glycolic acid nanoparticles prepared by a modified two step nanoprecipitation method using polyvinyl alcohol as stabilizer. Polysorbate-80 was used to coat the nanoparticles to further improve its passage through brain. Minitab 17 statistical software was employed to create general full factorial design. Drug-excipient compatibility study by Fourier transform infrared spectroscopy and differential scanning calorimetry revealed no possible interactions. Kinetic modelling of in vitro release showed that poly D,L-lactic-co-glycolic acid nanoparticles were more linear towards KorsemeyerPeppasmodel indicating drug release from the nanoparticles was by a combination of bulk degradation followed by diffusion (Fickian diffusion). The scanning electron microscopy studies showed that poly D,L-lactic-co-glycolic acid nanoparticles were found to be spherical with either smooth or rough at surface. Stability studies performed at refrigerator conditions (3-5±2º) showed no significant changes upon storage. Results of in vivo blood brain barrier crossing study showed that when compared with pure drug, the formulated nanoparticles carried the drug to brain effectively. Owing to the lower particle size and pharmacy and drug information, poly D,L-lactic-co-glycolic acid nanoparticles were able to pass through blood brain barrier effectively than chitosan nanoparticles. Also, the ability of poly D,L-lactic-co-glycolic acid to release drug in a sustained manner for weeks makes it a promising drug delivery system.

6 illus, 10 tables, 25 ref

041624   PRAMANIK A, SAHOO R N, NANDA A, PATTNAIK K P, MALLICK S (Siksha O Anusandhan (Deemed to be Univ), Bhubaneswar - 751 003, Email: profsmallick@gmail.com) : Swelling kinetics and corneal hydration level of kaolinin-HPMC hydrogel film. Indian J Pharm Sci 2020, 82(2), 306-14.

In this investigation, the effect of kaolin on hydration kinetics and swelling behavior of hydroxypropyl methylcellulose ocular film was studied. Gradual reduction in the extent of and rate of swelling of the film was noticed with increasing the content of kaolin. Peppas model revealed that the diffusion coefficient was increased in the presence of kaolin and also increased for the film of higher viscosity polymeric film. Peppas model suggested that the polymeric film followed the diffusion-controlled swelling mechanism. The Peleg rate constant was increased from 1.69 to 44.39 h/g indicating the initial water adsorption rate in the decreasing order while Peleg capacity constant did not vary significantly in the presence and absence of kaolin indicating lack of remarkable change of water adsorption capacity. The presence of kaolin in the film could maintain a safe corneal hydration level.

8 illus, 3 tables, 25 ref

045197   SUNGKONO (Physics Dep, Institut Teknologi Sepuluh Nopember, Surabaya- 601 11, Indonesia) : An efficient global optimization method for self-potential data inversion using micro-differential evolution. J Earth Syst Sci 2020, 129(1), 10.1007/s12040-020-01430-z.

Self-potential (SP) method has many applications, where the interpretation of SP data can be used for qualitative and quantitative interpretation. However, inversion of SP data in this paper is of quantitative interpretation and consists of highly non-linear, multimodal data and deploys global optimum method (GOM). Micro-differential evolution (MDE) is a GOM with small or micro-population size (5–8 populations) for each iteration. Consequently, this approach involves small numbers of forward computation in the inversion process. Two MDE variants, including adaptive MDE (μμJADE) and vectorized random mutation factor (MVDE) were tested first for different level of noises containing synthetic SP data with single anomaly and applied to synthetic SP data of multiple anomalies. The MDE variants are reliable and effective for inverting noisy SP data. Furthermore, in order to check the rationality of MDE variants, the algorithm is applied to seven field data from different applications, including groundwater exploration, shear zone tracing, water accumulation in landslides and embankment stability assessment. The model parameters revealed by MDE variants are accurate and show good agreement with the previous results estimated using other approaches. In addition, MDE variants also require fewer forward modelling calculations than other optimization approaches.

58 ref

045164   RAJAPARA H M, KUMAR V, CHAUHAN N, GAJJAR P N, SINGHVI A K (Physics Dep, Gujarat Univ, Ahmedabad- 380 009) : Bleaching of blue light stimulated luminescence of quartz by moonlight. J Earth Syst Sci 2020, 129(1), 10.1007/s12040-020-01474-1.

Moonlight is sunlight reflected from the moon’s surface. It is additionally modulated by the Earth’s atmosphere, dust and pollutants on its way to the surface of the Earth. This contribution reports the bleaching rates of blue light stimulated luminescence (BLSL) signal of Quartz under full moonlight exposure at the Earth’s surface. Quartz BLSL reduced to 70 % by an exposure of 5 hrs moonlight, is in contrast to ~90 % reduction in < 3 s with daylight. This was anticipated due to (a) reduced moonlight flux by about a factor of half a million (Agrawal in Lat. Am. J. Phys. Educ. 4(2):325–328, 2010; J. Phys. Astron. 5(1):1–15, 2017); (b) inverse power law dependence of bleaching efficiency on wavelength (Spooner in The validity of optical dating based on feldspar, Ph.D. Thesis, Oxford University, Oxford, 1993; Chen and McKeever in Theory of Thermoluminescence and related phenomena, World Scientific Publications, London, 1997, Chen and Pagonis in Thermally and optically stimulated luminescence: A simulation approach, Wiley and Sons, Chichester, 2011); and (c) moonlight and daylight have spectral peaks around 650 and 550 nm, respectively. Deconvolution of OSL components suggests that moonlight affects the fast component of OSL signal the most. This has ramification for the application in polar regions, where the availability of daylight is at a premium during the winter months. Within a given context, it is conjectured that this could be used to infer the seasonality of sediment transport.

3 illus, 29 ref