Impact on the chlorophyll concentration in the Bay of Bengal and Arabian Sea during Indian Ocean dipole mode

The chlorophyll (Chl) concentration in the seawater of the Bay of Bengal (BoB) and the Arabian Sea (AS) changes most during the Indian Ocean dipole (IOD) mode event. The empirical orthogonal function (EOF) of several oceanographic and atmospheric data was studied, using 9 years (1998–2006) of reanalysed satellite data. The variation of Chl during the period of September to November (SON) over the 9 years has been studied in this article. It has been found that significant enhancement of Chl in the BoB takes place during IOD years owing to the surface wind action, that is, wind-stress curl (WC), which favours the upwelling process, whereas the AS shows a decline in concentration of Chl owing to a reduced open ocean upwelling process.     

Folate encapsulation in PEG‐diamine grafted mesoporous Fe3 O4 nanoparticles for hyperthermia and in vitro assessment

Effective and targeted delivery of the antitumour drugs towards the specific cancer spot is the major motive of drug delivery. In this direction, suitably functionalised magnetic iron oxide nanoparticles (NPs) have been utilised as a theranostic agent for imaging, hyperthermia and drug delivery applications. Herein, the authors reported the preparation of multifunctional polyethyleneglycol‐diamine functionalised mesoporous superparamagnetic iron oxide NPs (SPION) prepared by a facile solvothermal method for biomedical applications. To endow targeting ability towards tumour site, folic acid (FA) is attached to the amine groups which are present on the NPs surface by 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride/N‐hydroxysuccinimide chemistry. FA attached SPION shows good colloidal stability and possesses high drug‐loading efficiency of ∼ 96% owing to its mesoporous nature and the electrostatic attachment of daunosamine (NH₃ ⁺) group of doxorubicin (DOX) towards the negative surface charge of carboxyl and hydroxyl group. The NPs possess superior magnetic properties in result endowed with high hyperthermic ability under alternating magnetic field reaching the hyperthermic temperature of 43°C within 223 s at NP''s concentration of 1 mg/ml. The functionalised NPs possess non‐appreciable toxicity in breast cancer cells (MCF‐7) which is triggered under DOX‐loaded SPION.Inspec keywords: nanoparticles, nanocomposites, mesoporous materials, colloids, biochemistry, nanomagnetics, molecular biophysics, tumours, superparamagnetism, drugs, toxicology, biomedical materials, nanofabrication, hyperthermia, cancer, magnetic particles, cellular biophysics, nanomedicine, iron compounds, drug delivery systems, filled polymers, biological organs, liquid phase depositionOther keywords: NP surface, colloidal stability, drug‐loading efficiency, hydroxyl group, magnetic properties, high hyperthermic ability, magnetic field, DOX‐loaded SPION, folate encapsulation, targeted delivery, antitumour drugs, specific cancer spot, magnetic iron oxide nanoparticles, theranostic agent, drug delivery applications, multifunctional polyethyleneglycol‐diamine, facile solvothermal method, biomedical applications, tumour site, amine groups, mesoporous superparamagnetic nanoparticles, PEG‐diamine grafted mesoporous nanoparticles, 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride‐N‐hydroxysuccinimide chemistry, daunosamine group, carboxyl group, breast cancer cells, temperature 43.0 degC, Fe₃ O₄      

Structural and electrochemical modification of graphitic carbons by vapor-phase iodine-incorporation

Pristine and mechanically-milled graphitic carbons were chemically modified by vapor-phase iodine-incorporation. The effectiveness of iodine uptake during vapor iodation was gauged for pristine and mechanically-milled graphite. The doping of electronegative iodine, which is capable of triggering charge transfer reaction with carbon, was found to develop structural disordering, carbon-polyiodide covalent compounds (C-I₃, C-I₅), enhanced mesoporosity and reduced BET surface area in graphitic carbons. These intrinsic changes in iodine-modified graphite led to improved non-faradaic capacitance and development of faradaic pseudocapacitive reaction at ∼3.2 V versus Li. As a result, iodation develops manifold (∼100%) increment in gravimetric and volumetric capacity of precursor graphite, when tested versus Li. The effect of iodine-incorporation on physical and electrochemical properties of graphite is reported in detail.     

High-Power Broadband Ytterbium-Doped Helical-Core Fiber Superfluorescent Source

Highly efficient operation of a double-clad ytterbium-doped helical-core fiber in a superfluorescent (nonlasing) configuration has been demonstrated. The fiber was cladding-pumped by a diode-stack at 976 nm and yielded 107 W of amplified spontaneous emission from the two ends of the fiber for 168 W of absorbed pump power in an output beam with a beam propagation factor (M²) of 2.8. At pump powers over 40 W, the slope efficiency with respect to the absorbed pump power was 76%. The emission spectrum spanned the wavelength range from 1030 to 1160 nm and the bandwidth (full-width at half-maximum) was 37 nm     

Distribution of mineral species in different coal seams of Talcher coalfield and its transformation behavior at varying temperatures

International Journal of Coal Science & Technology - Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the...     

Outage probability of SC receiver over exponentially correlated K fading channels

A mathematical expression for the outage probability of a selection combining diversity receiver with an arbitrary number of input branches is presented for exponentially correlated K fading channels. Numerical and simulation results are plotted and the effect of correlation, number of diversity branches and fading parameter on the outage performance of the receiver is studied. Results suggest that a correlation coefficient less than 0.5 may be used in practice.     

Size-dependent correction factors for absorption measurements using filter-based photometers: PSAP and COSMOS

Filter-based absorption photometers have been widely used to measure mass concentrations of black carbon (BC) by measurement of the absorption coefficient of BC. In these techniques, correction for the effect of multiple scattering by the filter medium is necessary, even if only BC particles are extracted by evaporating co-existing volatile compounds using a heated inlet. The correction depends on particle size, because it varies with the aerosol penetration depth into the filter. The size dependence has not, however, been taken into account in previous studies. For the first time, we quantify the particle size dependence of the sensitivities of two filter-based photometers, PSAP and COSMOS, using mono-disperse nigrosin particles, which were generated by the combination of a differential mobility analyzer and an aerosol particle mass analyzer. At diameters smaller than 200 nm, the absorption coefficients measured by PSAP and COSMOS were much larger than those calculated by Mie theory. The size-dependent correction factors for PSAP and COSMOS are determined by comparing the observed absorption coefficients at a flow rate of 0.7 standard liter per minute with those calculated by Mie theory. The correction factors to the mass absorption cross-section are also estimated for typical size distributions of ambient black carbon particles. The new factors reduce the mass absorption cross-sections measured by PSAP and COSMOS by 28–36% for typical ambient black carbon particles observed with an inlet heated to 400 °C.     

Tuning and Assessment of Proportional–Integral–Derivative Controller for an Automatic Voltage Regulator System Employing Local Unimodal Sampling Algorithm

Abstract—This article presents an approach for obtaining proportional–integral–derivative controller parameters for an automatic voltage regulator system based on a local unimodal sampling optimization algorithm. A conventional integral time of squared error objective function and modified objective functions in terms of integral time of absolute error, integral of absolute error, integral of squared error, peak overshoot, and settling time with appropriate weighting factors are employed to tune the controller parameters. Different objective functions are employed to obtain optimized proportional–integral–derivative controller gains. Superiority of proposed technique over some recently published modern heuristic optimization techniques, such as artificial bee colony algorithm, particle swarm optimization algorithm, and differential evolution algorithm, for the same automatic voltage regulator system is demonstrated. Simulation results reveal that the proposed proportional–integral–derivative controlled automatic voltage regulator system tuned by the local unimodal sampling algorithm with modified objective function exhibits better performance in terms of settling time, peak overshoot, and stability. The robustness of the system tuned by the proposed algorithm is also studied satisfactorily by varying the time constants of the automatic voltage regulator system in the range of –50% to +50% in steps of 25%.     

Electricity generation using solar parabolic dish system with thermoelectric generator—An experimental investigation

The present electricity grid installation cost as well as the tariff is quite high in India, particularly remote rural areas, to electrify houses. These problems can be easily solved by installing standalone systems that operate on one of the clean energy sources such as solar energy. An experimental analysis of generating electricity from a thermoelectric generator (TEG) powered by a solar parabolic dish concentrator device with aperture area and focal length of 12.6 m² and 2.42 m, respectively, is presented in this article. A TEG is made up of a thermoelectric module connected to a flat receiver by an absorber layer. The studies were carried out in Indian climatic conditions at the National Institute of Technology, Puducherry. Over a spectrum of beam radiation, the system's maximum energy conversion efficiency, as well as efficient electrical output, are evaluated and presented. The proposed system's average effective electrical efficiency is 0.424%, corresponding to the TEG's average energy conversion efficiency of 2.76%.