Design of fiber Bragg grating-based Fabry–Perot sensor for simultaneous measurement of humidity and temperature

A new sensor for simultaneous measurement of humidity and temperature is proposed. The sensor consists of Fabry–Perot cavity formed by two identical uniform fiber Bragg gratings. To make the cavity serves as humidity sensor, moisture sensitive polymer, which is polyimide, is coated on the FBG and on the cavity with different thickness. When the sensor is exposed to the relative humidity change, the polyimide will expand and stretch the fiber and induces strain on the FBG and on the cavity. The induced strain alters the grating period, cavity length and effective refractive index of fiber. The simulation results show that the humidity sensitivity and thermal sensitivity are 1.92 pm/%RH and 8.87 pm/°C, respectively, for polyimide coating thickness of 10 μm on the FBG and 15 μm on the cavity.     

INAA analysis of fish homogenate: IAEA-436 and IAEA-407

Detailed investigations have been carried out on the well-known method of spectrophotometric determination of boron particularly in uranium compounds as boron-curcumin complex after extraction into 2-ethyl hexane 1,3-diol (EHD) to understand a number of parameters, which have not been addressed earlier in the literature. These include (i) effect of different acid media on analytical results of boron which are employed for dissolution of nuclear fuel samples, (ii) effect of diluents namely ethyl alcohol and N,N-dimethyl formamide on sensitivity of method which are employed for final dilution, and (iii) studies on loss of boron, if any, during conversion of uranium compounds to U₃O₈. Based on the present studies, the existing procedure has been suitably modified to improve the sensitivity in the measurements. In addition, this paper also describes about interference studies with Al, Cr, Mg, Ca, Fe, Mn, Mo, F⁻ and W and amount of EHD on modified method. Absolute detection limit was found to be 10 ng. The precision and accuracy of the method, is 3% at level 100 ng·g⁻¹ of boron.     

Efficient enantioselective synthesis of tetramic acids and lactams from threonine

Regioselective Dieckmann and aldol cyclisations using an N-acyloxazolidine derived from threonine give substituted tetramic acids and pyroglutamates in high yield and enantioselectivity. These are easily deprotected under mild conditions to give products, some of which exhibit antibacterial activity.     

Numerical investigation of natural convection inside an inclined parallel‐walled channel

Steady two‐dimensional natural convection in an inclined parallel‐walled channel was investigated numerically. The full elliptic forms of conservation equations were solved together and the velocity vectors, temperature contours and local and average Nusselt number distribution were obtained. The comparisons of local and average Nusselt number with published experimental and numerical results indicate very good agreement. Results are presented for a single aspect ratio, L/b=24, over the range of Rayleigh number of 3–1000 and angle of inclination 0–90°. The results indicate that the overall channel average Nusselt number is reduced as the inclination angle is increased. Significant reductions in the overall Nusselt number are exhibited at high angle of channel inclination. Copyright © 2005 John Wiley & Sons, Ltd.     

“0.75 eV killer centre” in red-emitting GaP LEDs

Dark transient capacitance measurements have been used to investigate the deeplevel content of red GaP LEDs. Thermal emission rate data is obtained and the 0.75 eV “killer” centre is identified from the signature.     

Studies on tungstate gels

Summary The magnetic susceptibilities of certain vanadium pentoxide systems supported by kieselgur have been determined in the temperature interval 30° to 400° C. The plot of reciprocal susceptibility against temperature for all the systems studied indicates sudden deflections at temperatures which are about 150° lower than those of optimum catalytic activity. It has been suggested that these points may mark the temperatures of commencement of structural changes which may be responsible for the activity of these catalysts.

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Zusammenfassung Die magnetische Susceptibilit?t gewisser Vanadium-Pentoxyd-Systeme mit Kieselgur als Tr?ger wurden im Temperaturintervall zwischen 30 und 400° C bestimmt. Die Auftragung der reziproken Susceptibilit?t gegen die Temperatur zeigt für alle untersuchten Systeme pl?tzliche Knicke bei Temperaturen, die etwa 150° niedriger liegen als die optimale katalytische Aktivit?t. Es wird vermutet, da? diese Knickpunkte die Temperaturen des Beginns von Struktur?nderungen zeigen, die für die Aktivit?t dieser Katalysatoren verantwortlich sind.

     

Elastic scattering of neutrons from 28Si and 32S

The excitation functions in the elastic scattering of neutrons have been measured at several angles in the energy range 600–3600 keV. Data have been analyzed in terms of the Ericson fluctuation and energy-averaged angular distributions have been analyzed using the optical model including Hauser-Feshbach theory.     

trans-cis Photoisomerization of a photoactive yellow protein model chromophore in crystalline phase

We have studied the photoinduced trans/cis isomerization of the protonated form of p-hydroxycinnamic thiophenyl ester, a model chromophore of the photoactive yellow protein (PYP), in crystalline phase, by both fluorescence and infrared spectroscopies. The conversion from trans to cis configuration is revealed by a shift of the fluorescence peak and by inspection of the infrared maker bands. The crystal packing apparently stabilizes the cis photoproduct, suggesting different environmental effects from the solvent molecules for this model chromophore in liquid solutions or from the amino acid residues for the PYP chromophore.     

New concepts in neutrosophic graphs with application

A neutrosophic set is a generalization of an intuitionistic fuzzy set. Neutrosophic models give more flexibility, precisions and compatibility to the system as compared to intuitionistic fuzzy models. In this research study, we apply the concept of neutrosophic sets to graphs and discuss certain concepts of single-valued neutrosophic graphs. We illustrate the concepts by several examples. We investigate some interesting properties. We describe an application of single-valued neutrosophic graph in decision making process. We also present the procedure of our proposed method as an algorithm.