Single phase cool white light emitting novel Ca9Al(PO4)7:Dy3+ nanophosphor under NUV excitation

A series of novel single-phase white light-emitting Dy³⁺-doped Ca₉Al(PO₄)₇ nanophosphors was successfully synthesized at 1100 °C via solution combustion route. X-ray diffraction (XRD) and Rietveld refinement analysis of Ca₉Dy_0.03Al_0.97(PO₄)₇ sample confirmed that this phosphor had a trigonal crystal structure with space group R3c(161). Meanwhile, as-observed from the transmission electron microscopy (TEM) study; particles of Ca₉Dy_0.03Al_0.97(PO₄)₇ sample were found to have a quadrilateral shape with crystallite sizes around 40–60 nm which were also confirmed by the Debye Scherrer equation. Under near-ultraviolet (NUV) excitation at 350 nm, photoluminescence (PL) emission spectra of nanocrystalline Ca₉Al(PO₄)₇:Dy³⁺ phosphors showed two peaks at 481 nm and 572 nm corresponding to ⁴F_9/2?→?⁶H_15/2 and ⁴F_9/2?→?⁶H_13/2 transitions, respectively. The optimum concentration was found to be x?=?0.03 mol. The critical energy transfer distance was calculated to be 20 Å and further Huang analysis concluded the exact mechanism, i.e. dipole–dipole interactions responsible for concentration quenching in Ca₉Dy_xAl_(1?x)(PO₄)₇ samples. Furthermore, the Commission Internationale de I’Eclairage (CIE) chromaticity coordinates of Ca₉Dy_0.03Al_0.97(PO₄)₇ nanophosphor was calculated to be (0.260, 0.297) and this nanophosphor had correlated color temperature (CCT) of 11,332 K which is located in a cool white area. Existing results indicate that Ca₉Dy_0.03Al_0.97(PO₄)₇ nanophosphor may be considered as a favorable candidate in NUV-based single-phase cool white light-emitting diodes (WLEDs).

     

An investigation into the sorption of heavy metals from wastewaters by polyacrylamide-grafted iron(III) oxide

An adsorbent for heavy metals was synthesized by introducing carboxylate functional group into polyacrylamide-grafted hydrous iron(III) oxide. The product exhibits a very high adsorption potential for Pb(II), Hg(II) and Cd(II). The removal of metal ions by adsorption on adsorbent has been found to be contact time, concentration, pH and temperature dependent. The process follows first-order reversible kinetics. The intraparticle diffusion of metal ions through pores in the adsorbent was shown to be the main rate-limiting step. The optimum pH range for the removal of metal ions was found to be 5.0-6.0. The thermodynamic parameters such as free energy change, enthalpy change and entropy change have been calculated to predict the nature of adsorption. The adsorption data were fitted using the Langmuir equation and maximum adsorption for each metal was estimated using their respective Langmuir equation constants. The method was applied for synthetic wastewaters. NaCl regeneration has been tried for several cycles with a view to recover the adsorbed metal ions and also to restore the sorbent to its original state.     

Formulation of olanzapine nanosuspension based orally disintegrating tablets (ODT); comparative evaluation of lyophilization and electrospraying process as solidification techniques

Olanzapine (OLAN) as an antipsychotic agent has shown its potential in effective management of psychotic disorders however its use is limited because of its poor water solubility. The aim of present work was to improve solubility of OLAN by developing a stable nanocrystal based orally disintegrating tablets (ODTs), using hyperomellose as potential stabilizer. Comparative evaluation of electrospraying and lyophilization as solidification techniques was carried out to assess its effect on solid state properties of OLAN nanocrystals before transformation to ODTs.OLAN Nanosuspension was developed using antisolvent precipitation method and exhibited particle size, polydispersity index and zetapotential value of 223.1?±?1.5?nm, 0.105?±?0.4 and ?17.9?±?3.5?mV respectively. Solid powders obtained from both the solidification techniques were compared in terms of size after re-dispersion, particle morphology, surface area, pore volume and solid state of drug present. Subsequently ODTs were prepared from these powders with needful excipients and % amount dissolved was evaluated. Rate of dispersion was found to be higher for ODTs prepared using lyophilized powder (～84% in 5?min) while other characterization parameters were comparatively similar. Overall, Lyophilization resulted in powders with better bulk level properties in comparison to electrospraying process.     

Effect of rabadi fermentation on phytic acid and in vitro digestibility of barley

Rabadi, an indigenous fermented food, was prepared by mixing cereal flour with buttermilk, allowing it to ferment at 30, 35 and 40 °C for 6, 12, 18, 24 and 48 h and cooking the fermented mixture for 0.5 h with continuous stirring. Two types of rabadi were prepared i.e. autoclaved and unautoclaved. In autoclaved type of rabadi cereal flour was mixed with water, autoclaved (0.103 MPa = 15 psi for 15 min), cooled, mixed with buttermilk and fermented. As this type of rabadi was precooked prior to fermentation, hence, the fermented product did not require cooking afterwards, while in unautoclaved rabadi, barley flour and buttermilk were mixed, fermented and then cooked prior to consumption. Phytic acid was reduced drastically at all the temperatures and periods of fermentation in both autoclaved and unautoclaved type of rabadi; greater reduction occurred at higher temperature and duration of fermentation. A significant improvement in the in vitro digestibility of starch and protein was observed; maximum improvement was noticed when fermentation was carried out at 40 °C for 48 h in both the types of rabadi. Phytic acid had a significant (P < 0.05) negative correlation with digestibility (in vitro) of proteins and starch of barley flour rabadi.     

Development of a Practical Method for Using Ozone Gas as a Virus Decontaminating Agent

Our objective was to develop a practical method of utilizing the known anti-viral properties of ozone in a mobile apparatus that could be used to decontaminate rooms in health care facilities, hotels and other buildings. Maximum anti-viral efficacy required a short period of high humidity (>90% relative humidity) after the attainment of peak ozone gas concentration (20–25 ppm). All 12 viruses tested, on different hard and porous surfaces, and in the presence of biological fluids, could be inactivated by at least 3 log_10, in the laboratory and in simulated field trials. The ozone was subsequently removed by a built-in catalytic converter.     

Measurement of depression and neuropsychological impairment in HIV-1 infection.

Depression and neuropsychological (NP) impairment were examined in 30 HIV-1 seropositive symptomatic, 15 seropositive asymptomatic, and 14 seronegative control participants. Items on the Beck Depression Inventory (BDI) were separated into somatic and affective components to examine effects of illness on depression. Twenty-two NP tests tapped motor and psychomotor function, cognitive flexibility, and memory. The symptomatic seropositive group had the highest mean depression scores. However, these group differences were seen with the somatic component, not the affective. No significant correlations were obtained between NP tests and the affective component. Although 3 of 11 psychomotor measures were modestly correlated with the BDI total and somatic component, depression was generally unrelated to NP performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of individuals’ psychological states on their satisfaction with the GSS process

The use of group support systems (GSS) to improve the outcomes of, and satisfaction with, meetings is increasing. Our empirical study, drawing on the theory of job design, was initiated to investigate the relative contribution of both individual and group characteristics on GSS participants’ satisfaction with the process. Our field study found that when employees used a GSS to brainstorm on an issue of concern, two individual characteristics (locus of control and personal innovativeness) and one group characteristic (group cohesion) had significant impact on user satisfaction with the meeting process. Locus of control, however, was found to have an impact in the opposite direction to our assumptions. Computer anxiety, an individual characteristic, was not found to be significant.     

Analytical equations for compact dual frequency microstrip antenna

Design equations are presented for calculating the resonance frequencies for a compact dual frequency arrow‐shaped microstrip antenna. This provides a fast and simple way to predict the resonant frequencies of the antenna. The antenna is also analyzed using the IE3D simulation package. The theoretical predictions are found to be very close to the IE3D results and thus establish the validity of the design formulae. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12, 477–482, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mmce.10048     

Behaviour of a two-unit standby redundant system with imperfect switching and delayed repair

A 2-unit standby redundant system with imperfect switchover is considered. A repair facility is assumed to be available only at a fixed proportion of time. Failure-time distributions of units are exponential whereas repair-time distributions, distribution of time for the repairman to become available are general. The system has been investigated in detail by the help of semi-Markov process and closed form results are obtained for mean-time-to-system-failure, steady-state availability, expected number of occurrences of a state, expected profit and second moment of time in up state. Behaviour of several parameters has also been studied and several earlier models are included as particular cases.     

Magnetism and magnetotransport in sonochemically-prepared amorphous Co(100-x)Pt(x) nanoalloys

Amorphous nanoalloys of Co(100-x)Pt(x) (0 < or = x < or = 50) prepared sonochemically exhibit a negative magnetotransport effect, showing a maximum for platinum volume fraction of 10%. The oscillatory peak maxima observed in x = 30 composition for residual resistivity, rho0 and Tmin corresponds to the peak minima for the negative MR% in the range of compositions studied. We observe that in weakly exchange coupled amorphous alloys, the local magnetic order at Tmin and the disorder effects observed from rho0 become crucial.