Title: |
Two constraint preconditioners for generalized saddle point problems+ |
Authors: |
Cui-Xia Li || Shi-Liang Wu |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 01-04 |
Abstract: |
In this paper, we consider two new constraint preconditioners for generalized saddle point problems. The eigenvalue distribution of the related preconditioned matrix is discussed in detail. Theoretical analysis shows that all the eigenvalues of the preconditioned matrix are strongly clustered. |
Keywords: |
Generalized saddle point problems; eigenvalue; constraint preconditioner |
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Title: |
Thevenin analysis of alternating current R-C circuit for teaching and learning of electric circuit subject |
Authors: |
Ishak Annuar |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 05-08 |
Abstract: |
The paper presents the calculated and simulated of R-C alternating current (ac) circuit solved by using Thevenin method used for electric circuit subject. A MATLAB-Simulink (R2017b) was used for simulation purposes. A selected value of R-C ac circuit is developed for calculation and simulation, respectively. The simulation results of Vth and Zth using Simulink achieved lower percentage error Vth (0.102%) Zth (0.524% and 0.106%). The result showed simulated of Thevenin equivalent circuit is consistent with the calculated value with small error percentage. The first method of calculation of Zth achieved best result with the lowest percentage error of 0.106%. The result showed the successfully simulation by Simulink for Thevenin voltage and Thevenin impedance. |
Keywords: |
Simulink, Thevenin impedance, Thevenin voltage. |
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Title: |
Optimization of culture conditions and process parameter (pH)to enhance the production of DHA by using Schizochytrium sp. in submerged batch fermentation |
Authors: |
Ved Prakash Jangir || Anjali Pande || Snehlata || Ranjana || Deepak Prasad || Muskan Choudhary || HarshpalSingh |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 09-13 |
Abstract: |
Docosahexaenoic acid (DHA) is an important omega-3 fatty acid with many beneficial health effects on humans. Microalgae derived DHA has several advantages as compared to fish oil. Therefore, most of the commercial production is done now-a-days through fermentation using microalgae and Schizochytrium species are well studied in this regard. In the current study, Schizochytriumlimacinumwas used for optimization of culture conditions and process parameters for enhanced biomass and yield of DHA in fermentation. Our study highlights the use of initial culture growth attained after 28hours with pH and packed cell volume (PCV) values 5.8±0.2 and 05±1.0, respectively as lab inoculum for seed and production batch. Moreover, we studied the effect of varying pH(5.7±0.2, 6.2±0.2 and 6.8±0.2) on DHA production. Our results suggest that the optimal pH for maximum DHA production is 6.2±0.2 duringproduction fermentation batch. |
Keywords: |
Microalgae,DHA, fermentation, pH, extraction, HPLC |
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