Characterization and Studies on Hydro Dynamically Stable Operation of an Angular Jet SOG for COIL

Chemical oxygen-iodine Laser (COIL) is one of the fast emerging high power laser source for near Infrared (λ=1.315μm) laser generation. The heart of the system is the singlet oxygen generator (SOG) which is a pumping source for this laser. A Jet type SOG with a novel approach was designed and fabricated. Singlet oxygen was taken out of the SOG at an angle of 40° thus avoiding the carry over of droplets, which is one of the major drawbacks of horizontal system. The preliminary results have been reported in our earlier publication. The present paper discusses the performance of this generator for various operational conditions viz. diluent's gas nitrogen / helium, basic hydrogen peroxide composition, generator pressure and gas velocity. Further, conditions for the stable operation from generator as well as chlorine injection point of view have been identified.     

Induction of early and bioeffective antibody response in rodents with the luteinizing hormone-releasing hormone vaccine given as a single dose in biodegradable microspheres along with alum

Total urinary incontinence is a difficult problem faced by the urologist. Several techniques to increase ureteral resistance have been described. The majority of them rely on intermittent catheterization for bladder emptying, especially in neurogenic incontinence. We have developed a new procedure in which a bladder flap is used to create a neourethra. This urethral extension acts as a flap valve to provide continence. Bladder emptying is accomplished by clean intermittent catheterization. Urethral lengthening with an anterior bladder-wall flap was performed in 18 patients aged a mean of 8.9 years who had neurogenic incontinence (14) or exstrophy (4). Patients with previous bladder interventions received a lateralized anterior flap. Bladder augmentation was performed in 14 of the 18 patients [detubularized ileum (11), detubularized colon (3)]. The average follow-up period is currently 29.3 months. Continence was achieved in 13 of the 18 patients (72%). Complications included urethrovesical fistulae, which developed in two patients. Two patients could not perform catheterization due to pain but had no obstruction to passage of catheter (exstrophy). Ureteral lengthening with an anterior bladder-wall flap is a useful alternative for the surgical treatment of urinary incontinence. This technique achieves a good continence rate and presents few problems with catheterization.     

Semiconducting transparent thin films: their properties and applications

The present state of the art of transparent, electrically conducting films, with special reference to In₂O₃, SnO₂ and Cd₂SnO₄, has been reviewed. Various production techniques currently in use, and typical parameters used in the processes have been discussed in detail. Electrical and optical properties of these films have been reported as a function of various parameters, e.g. substrate temperature, doping, oxygen pressure, etc. Finally, the applications of these films in research and industry have been discussed in detail.     

Electrical studies on ceramic samples of Rb2Ti4O9, Rb2Ti5O11 and RbKTi4O9

Electrical conductivity studies have been reported on Rb₂Ti₄O₉, Rb₂Ti₅O₁₁ and RbKTi₄O₉ in the temperature range 373 K to 750 K. Three distinct regions have been identified in the log(σT) versus 1000/T plots, the lowest temperature region being attributed to extrinsic defects, the intermediate one to exchange of alkali ions and the highest temperature region to thermally created defects. A phase transition is indicated for each of the three compounds. The plot of resistivity with temperature further indicates the occurrence of a positive temperature coefficient of resistivity in RbKTi₄O₉.     

Electrical transport properties of polycrystalline HgTe films grown from mercury-rich HgTe

Measurements of the Hall coefficient and the d.c. conductivity were made on polycrystalline films prepared from mercury-rich HgTe. It was found that, in addition to grain boundary potential barrier scattering, the contribution of ionized impurity scattering is also quite significant. The effect of excess mercury in HgTe is to increase the mobility and to reduce compensating effects.     

Linear and non-linear optical transmission from multi-walled carbon nanotubes

The multi walled carbon nanotubes grown by the CVD technique were suspended in methanol and their linear and non-linear transmission properties have been studied. It is observed that the linear transmission spectrum, measured in the range 450–1100 nm, depicts features similar to those of single walled nanotubes. The observed features may be well characterized as the van-Hove singularities of the one-dimensional electronic density of states. Further, excellent non-linear optical properties have been observed in these suspensions. Experiments are conducted to study the optical limiting behavior in the visible (532 nm) as well as in the near infra-red (1064 nm) region by using a dual beam pulsed pump-CW probe, technique. The grown multi walled carbon nanotubes show a strong limiting behavior at both of these wavelengths. The recovery time as observed from the probe beam transmission is measured at different values of the incident pulse energy. The results are discussed in the light of the existing results.     

High-utility and diverse itemset mining

High-utility Itemset Mining (HUIM) finds patterns from a transaction database with their utility no less than a user-defined threshold. The utility of an itemset is defined as the sum of the utilities of its items. The utility notion enables a data analyst to associate a profit score with each item and thereof to a pattern. We extend the notion of high-utility with diversity to define a new pattern type called High-utility and Diverse pattern (HUD). The notion of diversity of a pattern captures the extent of the different categories covered by the selected items in the pattern. An application of diverse-pattern lies in the recommendation task where a system can recommend to a customer a set of items from a new class based on her previously bought items. Our notion of diversity is easy to compute and also captures the basic essence of a previously proposed diversity notion. The existing algorithm to compute frequent-diverse patterns is 2-phase, i.e., in the first phase, frequent patterns are computed, out of which diverse patterns are filtered out in the second phase. We, in this paper, give an integrated algorithm that efficiently computes high-utility and diverse patterns in a single phase. Our experimental study shows that our proposed algorithm is very efficient as compared to a 2-phase algorithm that extracts high-utility itemsets in the first phase and filters out the diverse itemsets in the second phase.

     

Optical waveguiding in amorphous tellurium oxide thin films

Optical waveguiding characteristics of amorphous TeO_2−x films deposited by reactive sputtering under different O₂:Ar gas mixtures are investigated on fused quartz and Corning glass substrates. Infra-red absorption band in the range 641-658 cm⁻¹ confirmed the formation of a TeO bond, and a 20:80 O₂:Ar gas mixture ratio is found to be optimum for achieving highly uniform and transparent films at a high deposition rate. As grown amorphous films exhibited a large band gap (3.76 eV); a high refractive index value (2.042-2.052) with low dispersion over a wide wavelength range of 500-2000 nm. Optical waveguiding with low propagation loss of 0.26 dB/cm at 633 nm is observed on films subjected to a post-deposition annealing treatment at 200 °C. Packing density and etch rates have been determined and correlated with the lowering of optical propagation loss in the annealed films.