Physical Sciences and Engineering

Early detection of bearing faults in rotating machines plays an important role in industrial plants since it avoids the occurrences of serious failure in many parts of the machinery that causes plant failure. It allows the detection of abnormalities and problems at incipient stages which helps in the early of intervention of maintenance and production personnel to keep the plant running and to avoid serious accidents. Therefore, the ability to predict the bearing failure at incipient stage is of great importance.

We consider the numerical solvers for discretized partial differential equations arising from different incompressible flows. We used the finite element discretization method to discretize the Navier-Stokes equations. IFISS (Incompressible Flow Iterative Solution Software) is used to obtained the different grids. We used preconditioned Krylov subspace methods to solve the resulting linear systems. Numerical experimental results are performed to compare the preconditioned iterative solvers for different types of the incompressible flows.

This work is devoted to geometrical research of the ray trajectories system. We consider trajectories of electrons moving in the second shell of an atom. The proposed model of movement of electrons is based on the geometrical interpretation of the Pauli Exclusion Principle and the geometric interpretation of distribution of electrons in energy levels, shells, and subshells of atoms in Mendeleev’s periodic table. It turned out that the second shell can be described by a cubic equation, Cardano’s formula, and a new system of triangles as well.

The elemental composition of TSP collected upon different wind sectors in the highly industrialized harbor of Dunkirk (France) were measured and the data was interpreted using a Non Negative Matrix Factorization (NMF) receptor model. Our objective was to identify the possible sources of TSP and to determine their relative contribution at the sampling site. We decided to carry out a daily sampling campaign at a fixed site and a sufficiently long period, i.e. 3 months, from February to May 2008.

The paper mentions concepts, common methods of online market research and advantages, disadvantages of each method. The author then suggests some solutions to strengthen the effectiveness of online market research application in the Library network of Vietnam National University – Ho Chi Minh City.  

On 8th August 2009, the extreme rainfall of typhoon Morakot dumped record breaking rain in southern Taiwan.  The typhoon significantly changed landscape patterns in Linbian Township, Pingtung County, in the southern part of Taiwan. Land use/land cover changes and the direct and indirect effects of these changes have drawn much public attention. This study aims at detecting typhoon Morakot induced land use changes and the dynamic landscape structure changes between 2006 and 2012. Three images from Formosat-2 satellite with resolution of 8 m were used for land use change detection.

Central Highland is one of the driest regions in Vietnam. Extended dry spells linked to El Nino phenomenon have raised serious concerns and often affects the local economy and livelihood of local residents. The main objective of this study is to assess causes of this worsening drought problem and to suggest possible solutions for alleviating this problem. In recent years, the exploitation of excess water sources for growing high cash crops such as coffee has caused a serious imbalance between surface water and groundwater.

The concentrations of natural radioactivity of 226Ra, 232Th and 40K and some heavy elements (Zn, Mn, Fe, Mn, Cu, Ni, and Pb) were measured in drinking water samples collected from different mosques in Makkah city, Saudi Arabia. A high-resolution HPGe detector was used for the natural radionuclides measurement. The average activity concentrations were 0.32, 0.12 and 10.96 Bql− 1 for 226Ra, 232Th, and 40 K, respectively.

This  document  presents  the  development  of  a system for detecting faults through fuzzy logic, using  different  parameters  such  as  poorly combusted hydrocarbons (HC), Carbon Dioxide (CO2),   engine   speed   (RPM),   and   Manifold Absolute Pressure Sensor (MAP) to predict the faults that  may occur  in  the  engine.  In order to determine the behavior of the inputs, there were generated different faults in a sonata 2.0 gasoline engine, such as poorly calibrated spark plugs, improper fuel pressure, air filter and catalytic converter clogging.

The new era of human genetic research has begun with the completion of Human Genome Project in 2003. Consequently, a standard functional human genome map has been produced depicting location, sequence, functions and mode of regulation of approximately one lakh genes of entire human genome. Because of advances in information and communication technology and genomic technologies, DNA sequencing, testing and manipulation are now faster, cheaper, and more accurate as compared to 15 years ago.