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This field investigation was conducted to assess the implication of the direct and residual effect of the applied differential level of boron on the dynamics of the soil chemical properties, nutrie...

Rainfall being a complex phenomenon governed by various meteorological parameters is difficult to model and forecast with high precision. For hilly regions such as state of Sikkim and adjoining areas of West Bengal, rainfall acts as lifeline. Several parametric models such as seasonal autoregressive integrated moving average (SARIMA) and exponential autoregressive (EXPAR) are very popular and extensively used to model and forecast rainfall. Owning to complex nature of rainfall series, non-parametric time delay neural network (TDNN) model has also gained substantial amount of attention by researchers. This study uses these two broad class of models and applies them to the monthly rainfall of Sub-Himalayan West Bengal and Sikkim. The models were compared based on their forecasting efficiencies and pattern prediction ability.

Education is a Nation’s strength. Association analysis of academic performance and its influential factors has remained research interest for all education researchers all over the world. India being an agriculture dominated country, for its development in agricultural front it requires ahuge numberof efficient technocrats having strong academic background. In this study an attempt has been made to examine the associationship of academic performance of the agriculture graduates, as measured through overall grade point average (OGPA) with the factors supposed to influence the academic performance. Special emphasis has been given to visualize the performance in presence of the influences of nominal factors. Students at masters level were surveyed for their social, economic, demographic and family and educational background through a designed questionnaire and tested accordingly. Statistical tools, starting from frequency, percentage, Chi-square test, test for normality, Cramer’s V test, multiple regression analysis with the inclusion of dummy variables were employed. Dependency of OGPA with gender, caste and expenditure on education is recorded. The dependency of educational expenditure on OGPA is quite obvious. But the dependency of OGPA with those of gender and caste is most probably not a good sign for a healthy higher education system. This study will help the education planners to take group oriented action plan for improving the education standard in higher education institutions.

Swarm intelligence is one of the most emerging methods used for autonomous mobile robot navigation. Researchers have developed many algorithms in mobile robot navigation by simulating the swarming behavior of various creatures like ants, firefly, honey bees, and cuckoo, and the findings are very motivating. The paper presents application and implementation of spider monkey optimization (SMO) along with Three Path method (TPM) for mobile robot navigation in cluttered environment. A collision-free path is selected by using TPM. When all the three paths are blocked by obstacles, SMO is used for obstacles avoidance. The finding of global and local leaders from the groups is the key concept of the proposed method. The proposed method efficiently improves the global search in less number of iterations, and hence, it can be easily implemented for real-time obstacle avoidance. The computational path and time are less as compared to other navigational methods. Some simulation results are presented at the end of the paper to show the effectiveness of the proposed navigational method.

The genetic variability of ‘Candidatus Liberibacter asiaticus’ (CLas) population associated with huanglongbing (HLB) disease of citrus in North Eastern (NE) region of India, a geographically locked region, and home for the diversity of many citrus species was analyzed on the basis of tandem repeat numbers (TRN) in variable CLIBASIA_01645 genomic loci. Fifty-five CLas strains sampled from different groves of NE Hill (NEH) region of India were in single amplicon group, but there was remarkable genetic variability in TRNs. The TRN in HLB-associated CLas strains varied from 0-21 and two novel repeat motifs were also identified. Among the NE population of CLas, TRN5 and TRN9 were most frequent (total frequency of 36.36%) followed by TRN4 (14.55%) and TRN6, TNR7 with a frequency of 12.73% each. Class II type CLas genotypes (5 < TRN ≤ 10) had highest prevalence (frequency of 60.00%) in the samples characterized in present study. Class I (TRN ≤ 5) genotypes were second highest prevalent (29.09%) in the NEH region. Further analysis of genetic diversity parameters using Nei's measure (H value) indicated wide genetic diversity in the CLas strains of NE India (H value of 0.58-0.86). Manipur CLas strains had highest genetic variability (0.86) as compared to Eastern, Southern and Central India. The R10 values (TRN ≤ 10/TRN > 10) of NE CLas population was 10.43 (73/7), higher from other regions of India. Present study conclusively reported the occurrence of high genetic variability in TRN of CLas population in North East Indian citrus groves which have evolved to adapt to the specific ecological niche.

Mobile robots can travel by acquiring the information using sensor-actuator control techniques from surrounding and perform several tasks. Due to the ability of traversing, mobile robots are used in different application for different places. In the field of robotic research, robot navigation is the fundamental problem and it is easier in static environment than dynamic environment. This paper presents a new method for generating a collision-free, near-optimal path and speed for a mobile robot in a dynamic environment containing moving and static obstacles using artificial neural network. For each robot motion, the workspace is divided into five equal segments. The multilayer perceptron (MLP) neural network is used to choose a collision-free segment and also controls the speed of the robot for each motion. Simulation results show that the method is efficient and gives near-optimal path reaching the target position of the mobile robot.

Controlled annealing induced evolution of local structure and magnetic properties on oleic acid coated and bare nanoparticles composed of iron oxy hydroxide and cubic iron oxides were studied using Mossbauer spectroscopy. Mutually opposite variation of quadrupole splitting and magnetic hyperfine field with respect to that of isomer shift has been observed in both the cases of bare and oleic acid coated nanoparticles subjected to annealing treatments. This manifests in an interesting linear correlation between quadrupole splitting and magnetic hyperfine field. Physics of the observed linear correlation between hyperfine parameters has been elucidated based on the direct proportionality of superexchange interaction on the hyperfine contact interaction and a strong dependence of the strength of superexchange interaction on the structural distortion and point defects mainly due to anionic vacancies. Thus the result of this study plausibly points to a strong coupling between local structure in terms of structural distortions and point defects with magnetic properties while the nanoparticles of iron oxides are subjected to coarsening and reduction.

Understanding the microscopic origin of physical properties is fundamental to the study of glasses. In the present study, unique trends were observed in structural and dynamical properties in lead-borate [xPbO:(1-x)B2O3] glasses upon increasing the modifier. Properties driven by short-range structural changes like, glass transition temperature (Tg) and elastic modulii exhibit a broad maxima around x = 0.3, in congruence with the average coordination number . Using Raman spectroscopy, this behaviour is attributed to the gradual conversion of three-coordinate (B3) to four-coordinate (B4) boron species. However, dynamic properties like the Boson peak and fragility behave similar to the above structural properties except an anomalous dip at x = 0.3. The corresponding dynamic correlation length, therefore, exhibits a decrease except a peak at x = 0.3 with increasing x. The static correlation lengths estimated from the first sharp diffraction peak (FSDP), did not follow a linear trend with the dynamic correlation lengths, indicating a different spatial origin. The analysis of the Boson peak and FSDP suggests that while the Boson peak arises from intermediate-range ordering within the network units, the FSDP arises due to ordering of voids between such units. Moreover, the Boson peak maximum showed a linear decrease with increasing , while the Boson peak position and fragility were found to vary linearly. These correlations emerge from the evolution of the network packing and connectivity with the addition of modifier and changing role of lead oxide as a glass former at higher concentrations. The anomalous variation in dynamical properties reflects the critical role of Pb2+ in tuning the intermediate-range structure of the vitreous network.

Stability of superparamagnetic magnetite nanoparticles as formed in Zeolite has been addressed in a detailed manner based on isochronal annealing studies using Mossbauer spectroscopy. A strong binding of these nanoparticles in Zeolite has been deduced as the coarsening of the nanoparticles is observed following annealing treatments beyond 825 K. In addition, the magnetic interactions between these superparamagnetic magnetite nanoparticles in the as dispersed condition in Zeolite have been elucidated by means of low temperature Mossbauer studies. A strong dependence of the dipole–dipole interactions between superparamagnetic particles of cubic iron oxides is deduced based on this study.

A simple synthesis method of chitosan functionalized Fe3O4-Au (Chit-Fe2O3@Au) nanoparticles (NPs) was developed. This method first prepared oleic acid-coated Fe3O4 (OA-Fe2O3) NPs as a precursor, followed by functionalization of chitosan to obtain Chit-Fe2O3@Au NPs. Structural and magnetic properties of both synthesized nanomaterials were examined by surface and spectroscopic techniques. An X-ray diffraction (XRD) study showed that the phases of Fe3O4 and Au had sizes of 5.9 and 11.2 nm, respectively. High resolution transmission electron microscopy (HRTEM) images demonstrated the formation of nearly spherical shaped composites in Chit-Fe3O4@Au nanostructures. Energy dispersive X-ray (EDX) spectroscopy measurements confirmed the presence of Au and Fe3O4 in the prepared nanomaterials. The capping of chitosan on Au and Fe3O4 surface was established using Fourier transform infrared (FTIR) spectroscopy measurements. Mossbauer spectra at 300 K showed an increase in superparamagnetic components. At 80 K, the Fe3O4@Au nanomaterials preserved 11% of superparamagnetic phase. Magnetization measurements revealed that the Fe3O4@Au nanomaterials had a saturation magnetization of 28 emu/g at 300 K and a blocking temperature of 117 K. The synthesized nanomaterials have potential in biomedical applications because of their high magnetic property with suitable binding sites for delivering drugs.

Magnetic interaction of the magnetite (Fe3O4) nanoparticles grown on zeolite has been studied. XRD patterns show that in the presence of 25–75 mg of zeolite the average particle size of Fe3O4 decreases to ≈6 nm, but with the increase of zeolite content (75 mg

We have studied the stoichiometry of magnetite nanoparticles using three spectroscopic techniques: Mossbauer, photoacoustic and ferromagnetic resonance (FMR). By varying the weight ratio of the Fe precursor to the reducing agent (sodium acetate) and a post-synthesis annealing, we were able to synthesize samples with different amounts of Fe vacancies, from stoichiometric Fe3O4 to γ-Fe2O3. By synthesizing magnetite in the presence of zeolite we obtained nanoparticles within the 3–10 nm diameter range. The spectroscopic results show that there is a correlation between the amount of Fe vacancies and (i) the optical absorption and (ii) the g-values from the Electron paramagnetic resonance EPR spectra of the nanoparticles.

Investigating the length-scales of order in glasses is important to understand glass properties and hence, the underlying glass structure. Addition of alkali oxides (M2O) in tellurite glass is well-known to modify its network and alter properties by conversion of its basic structural units of TeO4 → TeO3 and increasing the conversion upon further addition of M2O. In this study, we report results of our Raman and Brillouin scattering investigations on 0.12M2O:0.88TeO2 (M = Li, Na, K, Rb and Cs) glasses with an aim to study the effect of the specific alkali cation (M) at fixed composition, on the resulting network structure that determines their interesting optical properties. The network-polyhedral (TeO3) stretching vibrations exhibits red-shift while the Te–O–Te bending mode blue-shifts as M varies from Li to Cs. The fraction of terminal TeO4 units increase steeply with respect to TeO3 and also at the cost of TeO4 units within the network chains, with increasing size of M, contrary to earlier predictions that at fixed concentration of M2O, only the interactions between alkali cation (M) and anions of structural units change, keeping the network structure unaltered. A reduction in frequency with rising mass of M was observed for the Brillouin modes and the Boson peak. Combining results from these techniques, probing structure at different length-scales, depicts that even though increasing M size lowers the conversion of TeO4 to TeO3 units, still the network disintegrates further since the fraction of TeO4 with non-bridging oxygens (NBOs) enhance. This causes reduction in elastic modulus at a larger length-scale, even though specific intra-molecular interactions become stronger within the glass network. The increasing size of the cation from Li+ to Cs+, while preserving the charge of the alkali ion, helps distribute the same electric charge on larger number of anionic tellurite units of the network, and thus, enlarges the correlation length with M, while simultaneously decreasing the network strength. These observations provide evidence for the structural changes leading to the enhanced densities, increased band gaps, reduced refractive indices and the earlier-reported reduction in non-linear susceptibilities with increasing size and mass of M.

Enhancing the rate of decomposition or removal of organic dye by designing novel nanostructures is a subject of intensive research aimed at improving waste-water treatment in the textile and pharmaceutical industries. Despite radical progress in this challenging area using iron-based nanostructures, enhancing stability and dye adsorption performance is highly desirable. In the present manuscript alkali cations are incorporated into iron oxide nanoparticles (IONPs) to tailor their structural and magnetic properties and to magnify methyl blue (MB) removal/decomposition capability. The process automatically functionalizes the IONPs without any additional steps. The plausible mechanisms proposed for IONPs incubated in alkali chloride and hydroxide solutions are based on structural investigation and correlated with the removal/adsorption capabilities. The MB adsorption kinetics of the incubated IONPs is elucidated by the pseudo second-order reaction model. Not only are the functional groups of –OH and –Cl attached to the surface of the NPs, the present investigation also reveals that the presence of alkali cations significantly influences the MB adsorption kinetics and correlates with the cation content and atomic polarizability.

57Fe Mossbauer spectroscopy, XRD, and TEM were used to investigate the effect of mandelic- and salicylic acid coatings on the iron oxide nanoparticles. These two carboxylic acids have similar molecules size and stoichiometry, but different structure and acidity. Significant differences were observed between the Mossbauer spectra of samples coated with mandelic acid and salicylic acid. These results indicate that the occurrence of iron microenvironments in the mandelic- and salicylic acid-coated iron oxide nanoparticles is different. The results can be interpreted in terms of the influence of the acidity of carboxylic acids on the formation, core/shell structure, and oxidation of coated iron oxide nanocomposites.

The effect of Lithium insertion in the crystal structure and magnetic properties of Barbosalite [Fe3(PO4)2(OH)2], a polymorph of iron hydroxyl phosphate synthesized from variable Fe precursor (Fe(II) and Fe(III)), have been investigated. Effect of distortion in the crystal structure of Barbosalite appeared with minimum lithium hydroxide (LiOH.H2O) concentration of 0.5 M as depicted from the XRD patterns. Further, appearance of fresh peaks from 2 M is well matched with the crystal structure of LiFePO4. Studies with Mossbauer spectroscopy and SQUID Magnetometer intriguingly reveals that Li intercalation in the barbosalite affects only Fe(III) sites whereas the Fe(II) sites remains unaffected till 2 M. However, further increase in the Li concentration leads to structural transformation and results in LiFePO4 phase. Comparative studies of the structural and magnetic properties, magnetic transition are also discussed.

Composites of CoFe2O4 and ZnO (CFO@ZnO) nanomaterials were synthesized using double stage co-precipitation. The structural properties have been investigated by x-ray diffraction which shows the presence of hexagonal ZnO and spinel CoFe2O4. Variation in lattice parameters, after annealing at elevated temperature, indicates the diffusion of cations from the ZnO to CoFe2O4 and vice versa. Magnetic properties were measured by Mossbauer spectroscopy and superconducting quantum interference device magnetometer. The transition from ferrimagnet to paramagnet at 973 K is due to the formation of ZnFe2O4. High quadrupole splitting values in Mossbauer spectra depict the presence of interstitial Co defects. The Co cations diffuse in the ZnO lattice in the course of annealing at 1273 K, forming CoxZn1−xO resulting in ferromagnetism.

Mössbauer spectroscopic studies have been carried out at different temperatures across ferromagnetic to paramagnetic transition in Ni50Fe35Co15 and the evolution of hyperfine parameters such as centre shift and magnetic hyperfine fields with temperature has been studied. Mössbauer spectrum obtained at 300 K in Ni50Fe35Co15 exhibiting fcc crystal structure is a six line pattern with the mean value of the hyperfine field close to 33 Tesla. Ferromagnetic to paramagnetic transition has been observed to occur in this system around 895 K matching with that of magnetization results. Debye temperature of this nickel rich alloy is deduced to be around 470 K matching with that of Ni. Effect of prolonged annealing at 750 K on the magnetic property is also investigated with respect to the thermal stability of the alloy .

In an field experiment conducted on pea (Pisum sativum L.) during rabi season of 2013–14 in acid soil of Senapati district, Manipur, India phosphorus was given in the form of single super phosphate and levels of P2O5 kg ha-1 (0, 40 and 60) had significant influence on total dry matter yield, phosphorus concentration in plants and phosphorus uptake by plant. Six extractants were tried viz. Bray 1, Bray 2, Mehlich 1, Mehlich 3, Troug and Olsen to assess the available phosphorus status of the acid soils. The suitability of these extractants was in the descending order: Bray 1> Troug> Bray 2> Mehlich 3> Olsen (pH-8.5)> Mehlich 1. Bray's P 1 extractable phosphorus showed the highest and positive correlations with dry matter yield (control) phosphorus content (control), phosphorus uptake (control), Bray's percent yield and uptake. Therefore this extractant may be used as an index of available phosphorus for pea (Arkel) grown on acid soils of Senapati district, Manipur, the critical level being 14 ppm (mg/kg). The critical limit of phosphorus concentration in plant at 40 days of planting was 0.42% according to the graphical procedure of Cate and Nelson (1965) using a scattered diagram.