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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Title: |
Optimization of Separant Displacement in Artificial Barrier Height-Control Hydraulic Fracture |
Authors: |
Lu Haibing || Wang Xin || Yi Xinbin || Jiang Wei || Wang Tian || Sun Ting |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 14-22 |
Abstract: |
The main mechanism of artificial barrier height control is to change the stress difference between pay layer and barrier layers, but the artificial barriers method is mainly studied by experiment, and rarely in theoretical till now. Based on the hypothesis of (that) artificial barrier can be treated as a porous filter cake, this paper studied the laws of separant floating or sinking, and the porosity, permeability and specific resistance of the composition medium of separant. With the 3D fracture extent model, it can be developed into the theoretical model of artificial barrier laying optimization, programmed the model. At last use the oilfield data to verify the program. |
Keywords: |
Artificial Barrier; Fracture Height Control; Hydraulic Fracture; Separant Optimization |
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Title: |
Classification, Properties and Applications of titanium and its alloys used in aerospace, automotive, biomedical and marine industry- A Review |
Authors: |
Sani A. Salihu || Y.I. Suleiman || A. I. Eyinavi || Abdullahi Usman |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 23-36 |
Abstract: |
Titanium and its alloys are attractive engineering materials used in aerospace, automotive, biomedical, and marine industry because of their outstanding mechanical properties such as high specific strength and physical properties with excellent corrosion resistance and excellent elevated temperature properties. This paper presents a brief reviewonthe classification of titanium and its alloys associated with their chemical composition, properties and applications of titanium and its alloys used in aerospace, automotive, marine, and biomedical industry.The mechanical and physical properties were highlighted. Aerospace industry has been the major area of application of titanium alloys............ |
Keywords: |
Titanium alloys, classification, applications, aerospace and automotive industry, chemical composition |
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Title: |
Qualities Requirement forTeachers of Metal Works Technologyfor Efficient ServicesDelivery for Global Competitiveness |
Authors: |
beako, Y. T || okagwa P. O || dr Hillary Wordu |
Source: |
International Journal of Precious Engineering Research and Applications, Volume 4, Issue 3 (May-June) 2019), PP. 37-43 |
Abstract: |
The study assessed qualities required of Metal Works Technology teachersfor efficient services delivery for global competitiveness in Rivers State.Population of the study consists of16 VTE doctorate degree Students of Rivers State University, Port Harcourt and 19VTE doctorate degree Students of Ignatius Ajuru University of Education, Rumuolumeni, Port Harcourt. No sampling was taken considering the small size of the population. Self-structured instrument was designed to elicit information from the respondents. Test re-test method was used to determine the Reliability Co-efficient of the instrument where the results were correlated using Pearson Product Moment coefficient to determine the reliability coefficient which yielded a value of 0.86. The findings revealed that teachers who are regular and punctual to classes, teach according to set objectives, posse qualified academic credentials, grounded in method and procedure relevant to build capacity and among others............. |
Keywords: |
Qualities, Efficient services, Metal work Technology, Global Competitiveness |
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