Production and Characterization of Endocylanase from Bacillus Pumilus Using Solidstate Fermentation and its Application in 'Paper Pulp Processing

In the present studies it is clear that Bacillus pumilus xylanase is having the characteristic suited for an industrial enzyme (xylanases that are active and stable at elevated temperatures and alkaline pH are needed). SSF production of xylanases and its application appears to be an innovative technology where the fermented substrate is the enzyme source that is used directly in the bleaching process without a prior downstream processing. The direct use of SSF enzymes in bleaching is a relatively new biobleaching approach. This can certainly benefit the bleaching process to lower the xylanase production costs and improve the economics and viability of the biobleaching technology. The application of enzymes to the bleaching process has been considered as an environmentally friendly approach that can reduce the negative impact on the environment exerted by the use of chlorine-based bleaching agents. It has been demonstrated that pretreatment of kraft pulp with xylanase prior to bleaching (biobleaching) can facilitate subsequent removal of lignin by bleaching chemicals, thereby, reducing the demand for elemental chlorine or improving final paper brightness. Using this xylanase pre-treatment, has resulted in an increased of brightness (8.5 Unit) when compared to non-enzymatic treated bleached pulp prepared using identical conditions. Reduction of the consumption of active chlorine can be achieved which results in a decrease in the toxicity, colour, chloride and absorbable organic halogen (AOX) levels of bleaching effluents. The xylanase treatment improves drainage, strength properties and the fragility of pulps, and also increases the brightness of pulps. This positive result shows that enzyme pre-treatment facilitates the removal of chromophore fragments of pulp there by making the process more environment friendly

Line of Brillouin-Erbium Fiber Laser Utilizing a Fabry-Perot Cavity in L-band

In this paper, the generation of a multiwavelength laser source from a Brillouin -Erbium fiber laser in the long wavelength band (L-band) region is experimentally demonstrated. The proposed laser system utilizes a Fabrv-Perot cavity formed by fiber-loop mirrors. Twenty-four lines of Brillouin-Stokes with line spacings of 10 GHz are obtained in the L-band region

Analysis of Cavity Backed Printed Dipoles

The closed form expression for the radiated power of a half-wave microstrip patch is modified to calculate the impedance bandwidth of a printed dipole. Analyses of cavity backed flared and end-loaded printed dipoles are presented

Improved Loaded Quality Factor of Cavity Resonators with Cross lris Coupling

The performance of circular, rectangular and cross irises for the coupling of microwave power to rectangular waveguide cavity resonators is discussed. For the measurement of complex permittivity of materials using cavity perturbation techniques, rectangular cavities with high Q-factors are required. Compared to the conventional rectangular and circular irises, the cross Iris coupling structure provides very high loaded quality factor for all the resonant frequencies. The proposes cross iris coupling structure enhances the accuracy of complex permittivity measurements.

Broadband coaxial cavity resonator for complex permittivity measurements of liquids

A novel cavity perturbation technique using coaxial cavity resonators for the measurement of complex permittivity of liquids is presented. The method employs two types of resonators (Resonator I and Resonator II). Resonator I operates in the frequency range 600 MHz-7 GHz and resonator II operates in the frequency range 4 GHz-14 GHz. The introduction of the capillary tube filled with the sample liquid into the coaxial resonator causes shifts in the resonance frequency and loaded Q-factor of the resonator. The shifts in the resonance frequency and loaded Q-factor are used to determine the real and imaginary parts of the complex permittivity of the sample liquid, respectively. Using this technique, the dielectric parameters of water and nitrobenzene are measured. The results are compared with those obtained using other standard methods. The sources of errors are analyzed.

Studies on pulp propogation in single mode optical fibres

Studies on pulse propagation in single mode optical fibers have attracted interest from a wide area of science and technology as they have laid down the foundation for an in-depth understanding of the underlying physical principles, especially in the field of optical telecommunications. The foremost among them is discovery of the optical soliton which is considered to be one of the most significant events of the twentieth century owing to its fantastic ability to propagate undistorted over long distances and to remain unaflected after collision with each other. To exploit the important propertia of optical solitons, innovative mathematical models which take into account proper physical properties of the single mode optical fibers demand special attention. This thesis contains a theoretical analysis of the studies on soliton pulse propagation in single mode optical fibers.