Effects of Segmentation and Step Sampling on Apodized Fiber Bragg Grating

Practical implementation of apodized fiber Bragg grating results in approximation to the apodization profile. In this study, these profiles are simulated by sampling and segmentation. Segmenting an ideal profile is basically producing its corresponding piecewise linear profile. The number of segments varies with the error value, which is defined as the maximum absolute difference between the segmented profile and the ideal one. The relationship between the error and the number of segments is found to be one to many. To study the process normal and DWDM gratings have been considered. The quality of the fiber Bragg gratings was investigated through the maximum reflectivity, the SLSR, and the bandwidth of the normal gratings, the insertion loss, the bandwidth, and the crosstalk parameters for the DWDM gratings. Some of the results are wlexpected. Segmentation enhances the quality of the gratings for some error values. For example, side lobe suppression ratio for normal grating apodized with segmented profile is improved by around 5.8dB at error of 0.015 compared to the grating apodized with smooth function. An enhancement of 0.5% on the maximum reflectivity is also achieved for these normal gratings. For DWDM gratings the insertion loss is decreased by an amount of 0.002dB and the adjacent crosstalk is improved by an amount of around 2.5dB for some approximated Cosine apodization profile. The study was also done to investigate the sampling effect. Sampling rate was varied for a fixed value of the maximum error. The study showed a good grating quality over a wide range of sampling. This would have an impact of relaxing the practical implementation of such process. In order to explain the results obtained, a criteria was formulated. This is based on the integration of error function. This criterion was instrumental in explaining the results

Optimasi Ekstraksi Silika dan Alumina dari Lumpur Sidoarjo

Optimization of silica and alumina extraction from Sidoarjo mud have studied. The aim of this research is to know the optimum condition of silica and alumina extraction from Sidoarjo mud. Optimum condition of extraction is studied by variying the concentration and solvent used in the extraction process. Hydrochloric acid and NaOH were used in silica and alumina extraction from Sidoarjo mud. Hydrochloric acid was added to the filtrate of NaOH extract to obtain Al(OH)3 at pH 8, further the HCl added until pH 4 to obtain Si(OH)4. The filtrate of HCl extract wad added by NaOH until pH 4 to precipitate Fe(OH)3, further NaOH was added until pH 8 to obtain Al(OH)3. The result of this experiment shows that extractions result was affected by the concentration and the solvent used. The optimal concentration of solvent for extraction prosses is 6 M for both acid and base. The purest silica in this research was obtained from NaOH extract with the purity level of 95,6%

Experimental Study of Simultaneous Heat and Mass Transfer in Falling Film and Bubble Mode (LiCl) Absorbers

The study involves lithium-Chloride absorption process for the falling film and bubble columns absorbers, working at the same operating conditions. The results obtained were used to analyze the transfer process during the absorption of water vapor in the aqueous solution of LiCl. The performance of both absorbers was investigated for various solution flow rates (0.1-0.5)kg/min , various gas flow rates (1-9) lit/min and inlet solution concentration (40-50) wt% . Results showed that bubble absorber is superior to the falling film mode for mass and heat transfer and that the efficiency of bubble columns is more than that of falling film absorbers. Increasing the solution flow rates rarely affected the mass transfer, but improved the heat transfer. To evaluate the performance of mass and heat transfer, experimental results obtained were plotted as Nusselt and Sherwood number versus operating conditions respectively for falling film and bubble modes. A power law correlations were obtained for the objective functions (i.e., mass and heat transfer coefficients ) with correlation coefficient between (0.91 and 0.97)

Dirac theory on a space with linear Lie type fuzziness

A spinor theory on a space with linear Lie type noncommutativity among spatial coordinates is presented. The model is based on the Fourier space corresponding to spatial coordinates, as this Fourier space is commutative. When the group is compact, the real space exhibits lattice characteristics (as the eigenvalues of space operators are discrete), and the similarity of such a \emph{lattice} with ordinary lattices is manifested, among other things, in a phenomenon resembling the famous \emph{fermion doubling} problem. A projection is introduced to make the dynamical number of spinors equal to that corresponding to the ordinary space. The actions for free and interacting spinors (with Fermi-like interactions) are presented. The Feynman rules are extracted and 1-loop corrections are investigated.Comment: 1+14 pages, no figure

Bending experiment on a novel configuration of composite system using rebar as shear connectors with partially encased cold-formed steel built-up beams

In order to achieve greater ductility and strength, as well as to produce a more economical design, a novel composite beam and floor system have been developed to achieve higher strength and ductility, as well as to yield a more economical design purpose. This paper has put focus on this newly developed composite beam system which consists of a profiled metal decking slab made with self-compacting concrete (SCC). It has been joined cold-formed steel (CFS) built-up beams. These beams have been infilled with SCC by means of U-shaped rebar used as shear connectors. The researcher, in order to construct an open section, put together two CFS C-lipped channel sections in a back-to-back formation, and to construct a closed section, the formation was made to be toe-to-toe. The flexural behaviour of the partly encased composite beam was evaluated through experimentation by the researchers. So that the researchers could observe the failure modes and flexural capacity of the construction, a four-point bending test procedure was performed on two samples taking into consideration both closed and open built-up beam sections. The results of the test demonstrated that the open sections were able to exhibit a 24 percent higher ultimate moment capacity as well as greater stiffness and higher vertical deflection. As can be seen from the results of the experimental bending test, the built-up design had a great impact on the capacity and deflection of the section, and the section that was encased was able to reach the ultimate strength when the proposed shear connector was placed in the composite action. In order to validate the present test results, the design and analysis of the new composite beams have been evaluated

Effectiveness of Antibiotic Prophylaxis for Leptospirosis among Adults: A Systematic Review

Leptospirosis is one of the most widespread re-emerging zoonoses in the world. Malaysia is known to be an endemic country for human leptospirosis, with a case fatality rate of 2.11%, and an average annual incidence rate of 7.80 cases per 100,000 individuals. This systematic review is conducted to determine the effectiveness of antibiotic prophylaxis for leptospirosis among the adult populations who are highly at risk of getting infected. A systematic search was performed for the relevant titles, abstracts and keywords on PubMed, Scopus, Cochrane and Google Scholar from inception to November 2017 based on the PICO strategy; which returned 126 studies. Screening of abstracts had shortlisted 19 studies and data extraction was conducted for 8 studies which had been accepted after review of the full text. For the evaluation of antibiotics prophylaxis effectiveness against leptospirosis, only trials and cohort studies with risk ratio (RR) were selected. The articles were analyzed from the viewpoint of the dosage, adverse effects, study settings and effectiveness of the antibiotic prophylaxis. Using fixed effects model, pooled RR showed protective association between antibiotic prophylaxis use against the incidence of leptospirosis (RR = 0.31; 95% CI: 0.20, 0.48). Antibiotic prophylaxis for leptospirosis had been shown to be effective in preventing the incidence of the disease among high-risk populations and carries minimal adverse effects. It is recommended that the practice of antibiotic prophylaxis for leptospirosis is included in the standard protocol for leptospirosis prevention among people at high-risk, including disaster response teams and patrons of eco-sports tourism activities; with the drug of choice being doxycycline, either as a single 200 mg dose or weekly dose of 200 mg for the duration of exposure, based on the setting, duration of event and resources available