Erratic fluctuations in 14.5A GeV/c 28Si−AgBr Collisions

Analysis of multiparticle production data on 14.5A GeV/c ²⁸Si?AgBr collisions in terms of erraticity is carried out and the results are compared with those obtained from the Monte Carlo simulated data (using event generator HIJING). It is shown that like the multifractal spectrum through G _qmoments, erraticity spectrum may also be constructed from the observed power-law behaviour of the erraticity moments. Further, for examining the dominance of statistical fluctuations over the erraticity behaviour, correlation-free Monte Carlo events are simulated and analyzed. A comparison of the experimental and simulation results indicates that the fluctuations observed in the case of experimental data are not only because of the statistical reasons, but may have some dynamical origin.     

Infrared behaviour and the bare Pomeron intercept in a Reggeon Field Theory including the Pomeron and thef-pole

An extension of the critical Reggeon Field Theory that includes both the Pomeron and thef-Reggeon fields is constructed. The quantum numbers of thef-Reggeon allows specific Reggeon-Pomeron couplings that have not been considered previously in standard works on secondary trajectories. We show the existence of a single fully stable fixed point among a total of 11 points. Unfortunately this point does not satisfy the factorization requirements imposed by thef-dominance of the Pomeron hypothesis and, in consequence, the critical Pomeron can not bef-dominated in aP+f model. We have also evaluated the value of the intercept of the bare critical Pomeron, using the method of integral representations of the propagators. The value obtained is clearly higher than the one previously obtained without thef-Pomeron interplay. With an adequate choice of the values of the bare coupling constants its value is in good agreement with the phenomenological one.     

Use of high performance liquid chromatography in defining the abnormalities in the free amino acid patterns in the cerebrospinal fluid of patients with aseptic meningitis.

Free amino acids were quantitatively determined in cerebrospinal fluid (CSF) and plasma samples from patients with aseptic meningitis by a newly developed high performance liquid chromatographic (HPLC) method. The method of analysis was based on precolumn derivatization of orthophthaladehyde in the presence of 2-mercaptoethanol and detection was made at Eex = 340 nm and Eem = 450 nm. The method was sensitive and the limit for detection was less than 1 pmol for most of the amino acids. It took 45 min to separate 26 amino acids with highly reproducible results, giving a coefficient of variance for retention times and integrated areas less than 0.4% and 2%, respectively, after five replicate runs. The results accumulated in 10 patients were compared statistically with 11 age-matched healthy controls. Among the amino acids almost all the neurotransmitter candidates, such as aspartic acid, glutamic acid, glutamine, glycine, tyrosine, phenylalanine and gamma-aminobutyric acid (GABA), were significantly increased in the patients' CSF, whereas arginine and threonine were low. No change was observed in plasma amino acids in patients as compared to healthy controls. The higher levels of most of the neurotransmitters, especially GABA, aspartic acid and glutamic acid, could be used diagnostically in assessing the progression and remission in aseptic meningitis.     

Application of a flame photometric detector to the gas chromatographic measurement of sulphur compounds in hydrocarbon fractions

Summary Analysis of individual sulphur compounds in a complex hydrocarbon matrix is complicated either by quenching or by simultaneous hydrocarbon response. In the latter case the hydrocarbon response can be subtracted by opposing the signals from two different detectors, leaving a simplified chromatogram of the sulphur compounds.Presented at the 14th International Symposium on Chromatography London, September, 1982     

An efficient pathway for Li<Superscript>6</Superscript> isotope enrichment

Separation of lithium isotopes has been achieved using two-step laser photoionization in conjunction with an atomic beam and in-house built time of flight (TOF) mass spectrometer. We present an efficient pathway for the enrichment of Li⁶ isotope by tuning the exciter laser to the 3p ² P _{1/2, 3/2} excited state of Li⁶. A concentration of up to 60% is demonstrated from a natural isotopic abundant lithium sample. In addition, the first measurement of the absolute photoionization cross-section of the 3p excited state of Li⁶ and Li⁷ are reported as 26.8±4 Mb and 25.5±3.8 Mb, respectively. PACS 32.10.Bi; 32.80.t; 32.80.Fb     

Resonantly enhanced three-photon excitation spectra of lithium

We present the first measurement on the resonantly enhanced three-photon excitation spectra of natural lithium using a Nd:YAG laser pumped dye laser in conjunction with a thermionic diode ion detector. Exploiting the linear and circular polarizations, the np ²P_3/2(8 ? n ? 11) and nf  ²F_7/2 (8 ? n ? 38) series have been observed via three-photon excitation from the ground state. The measured level energies reveal a dynamic shift from calculated values, which increases with an increase of the principal quantum number n. The ac stark shift and line broadening mechanisms are studied as a function of laser intensity. It is noted that the width increases and the line center shifts towards the higher energy side as the laser intensity is increased. The maximum observed shift for the 12f ²F_7/2 line is 0.33 cm⁻¹ corresponding to the laser intensity variation from 1.34 × 10¹² W/m² to 1.03 × 10¹³ W/m², whereas its width increases from 0.36 cm⁻¹ to 0.82 cm⁻¹.     

Simultaneous investigation of MHD and convective phenomena on time-dependent flow of Carreau nanofluid with variable properties: Dual solutions

In countless applications, there is a thoughtful necessity for augmenting the poor thermal conductivity of conventional liquids to improve effectual heat transfer liquids. Nanofluids are fluids interruptions of nanoparticles and broad scrutiny have been presented on nanoliquid solicitations in heat transfer progressions. The intention of this exertion is to scrutinize the dual nature solutions of unsteady magnetite Carreau nanofluid influenced by porous stretching/shrinking surface. The phenomena of heat and mass transfer have been established in the manifestation of combined convective conditions with heat sink/source and variable thermal conductivity. By utilizing compatible conversions to rehabilitate the structure of nonlinear partial differential equations (PDEs) into nonlinear ordinary differential equations (ODEs) which were then elucidated numerically via bvp4c. Under the impact of diverse somatic parameters the graphical depiction of all the probable dual solutions of velocity, temperature, concentration, skin-friction coefficient, local Nusselt and Sherwood numbers are scrutinized. These outcomes specify that the liquid velocity display similar tendency for both upper and lower solutions and decline for unsteadiness parameter, while it enhance for Weissenberg number.     

Development of surface treated nanosilica for wettability alteration and interfacial tension reduction

The present study examines and compares the effect of surface treatments of nano-silica using internal olefins sulphonates (IOS_20–24 and IOS_19–23), anionic surfactants. The effect of surface modification on colloidal stability, wettability alteration and oil-water interfacial tension reduction were analyzed. Silica nanoparticles were characterized using Field Emission Scanning Electron Microscope (FESEM) and integrated energy-dispersive X-ray spectroscopy (EDX) before and after surface treatment. Using Turbiscan classic, the optimal nanosilica concentration and inspection of the coated particles dispersion stability with the help of light transmission behavior through the nanofluid was carried out. The stability was found to be enhanced as the mean light transmission declined only after surfactant treatment in both IOS coated nano-silicas but IOS_19–23 O-342 coated dispersions proved to be more stable among all three. RAME-HART Goniometer was used to perform interfacial tension (IFT) and contact angle measurements. IFT was found to be reduced by 48% after the surfactant treatment in case of IOS_19–23 O-342 coated nanosilica. Both surface treatments of nanosilica and increasing silica concentration caused significant reduction and altering wettability towards more water wet. The results revealed that IOS coatings improved the efficiency of NPs dispersion in terms of altered wettability and reduced IFT that mimics their potential for EOR applications.     

Homogeneous Molecular Iron Catalysts for Direct Photocatalytic Conversion of Formic Acid to Syngas (CO+H2)

The catalytic decomposition of formic acid to generate syngas (a mixture of H₂ and CO) is a highly valuable strategy for energy conversion. Syngas can be used directly in internal combustion engines or can be converted to liquid fuels, meeting future energy challenges in a sustainable manner. Herein, we report the use of homogeneous molecular iron catalysts combined with a CdS nanorods (NRs) semiconductor to construct a highly efficient photocatalytic system for direct conversion of formic acid to syngas at room temperature and atmospheric pressure. Under optimal conditions, the photocatalytic system presents an activity of 150 mmol g_catalyst^?1 h^?1 towards H₂, and an apparent quantum yield (AQY) of 16.8 %, making it among the most active noble‐metal‐free photocatalytic systems for H₂ evolution from formic acid under visible light. Meanwhile, these iron‐based molecular catalysts also demonstrate remarkable enhancement in CO evolution with robust stability. The mechanistic role of the molecular catalyst is further investigated by using cyclic voltammetry, which suggests the formation of Fe^I species as the key step in the catalytic conversion of formic acid to syngas.     

Amelioration in the Detection of Chlorine Using Electric Field Assisted LIBS

The detection of chlorine and improvement in its detection has remained a challenge despite the use of a single pulse and a dual pulse laser induced breakdown spectroscopic technique (LIBS). In this article, we presented an alternate technique for improving the detection of chlorine (Cl) using LIBS in conjunction with an external electric filed. A comparison of the emission intensity enhancement and plasma parameters in the absence and presence of an external field has been also presented. The implication of the presented technique for the detection of Cl is much easier and inexpensive as compared with the dual pulse LIBS.