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Parasuraman Basker,Pichai Kannan,Karumana Gounder Kolandaswamy 질병관리본부 2014 Osong Public Health and Research Persptectives Vol.5 No.1
Objectives: To know the prevalence of leptospirosis cases reported in private clinics among fever cases in Villupuram District, Tamil Nadu, India to know its real magnitude of the problem and to diagnose Leptospirosis among fever cases from differential diagnosis. Methods: 1502 Blood serum samples collected from three urban towns namely Kallakurichi (Latitude: 11' 73' N; Longitude: 78' 97' E), Villupuram (Latitude: 11' 75' N; Longitude: 79' 92' E) and Thindivanam (Latitude: 12' 25' N; Longitude: 79' 65' E) in fifteen clinics based on case definition of leptospirosis delineated by the National Vector Borne Disease Control Programme (NVBDCP), Government of India. Samples were tested in the laboratory of the Zonal Entomological Team (ZET), Cuddalore with Macroscopic Slide Agglutination Test (MSAT) and Ig-M ELISA. Result: There were 65 positive cases detected from 1502 blood serum samples in both MSAT and Ig-M ELISA. It could be known that there was 4% cases contributed from private clinics among fever cases. From this study, further it was known that all age groups of people affected irrespective of sexes based on their living condition associated with the environment prevailed of the disease. Conclusion: From this study, it was quantified that 4% of cases reported in private clinics among fever cases and its findings ascertained both the importance of differential diagnosis as well as reports that should be included to the Government for knowing its real magnitude for planning.
Rattapoohm Parichatprecha,Pichai Nimityongskul 사단법인 한국계산역학회 2009 Computers and Concrete, An International Journal Vol.6 No.3
This study aims to develop a cost-based high-performance concrete (HPC) mix optimization system based on an integrated approach using artificial neural networks (ANNs) and genetic algorithms (GA). ANNs are used to predict the three main properties of HPC, namely workability, strength and durability, which are used to evaluate fitness and constraint violations in the GA process. Multilayer back-propagation neural networks are trained using the results obtained from experiments and previous research. The correlation between concrete components and its properties is established. GA is employed to arrive at an optimal mix proportion of HPC by minimizing its total cost. A system prototype, called High Performance Concrete Mix-Design System using Genetic Algorithm and Neural Networks (HPCGANN), was developed in MATLAB. The architecture of the proposed system consists of three main parts: 1) User interface; 2) ANNs prediction models software; and 3) GA engine software. The validation of the proposed system is carried out by comparing the results obtained from the system with the trial batches. The results indicate that the proposed system can be used to enable the design of HPC mix which corresponds to its required performance. Furthermore, the proposed system takes into account the influence of the fluctuating unit price of materials in order to achieve the lowest cost of concrete, which cannot be easily obtained by traditional methods or trial-and-error techniques.
Simulation of concrete shrinkage taking into account aggregate restraint
Tangtermsirikul, Somnuk,Nimityongskul, Pichai Techno-Press 1997 Structural Engineering and Mechanics, An Int'l Jou Vol.5 No.1
This paper proposes a model for simulating concrete shrinkage taking into account aggregate restraint. In the model, concrete is regarded as a two-phase material based on shrinkage property. One is paste phase which undergoes shrinkage. Another is aggregate phase which is much more volumetrically stable. In the concrete, the aggregate phase is considered to restrain the paste shrinkage by particle interaction. Strain compatibility was derived under the assumption that there is no relative macroscopic displacement between both phases. Stresses on both phases were derived based on the shrinking stress of the paste phase and the resisting stress of the aggregate phase. Constitutive relation of paste phase was adopted from the study of Yomeyama, K. et al., and that of the aggregate phase was adopted from the author's particle contact density model. The equation for calculating concrete shrinkage considering aggregate restraint was derived from the equilibrium of the two phases. The concrete shrinkage was found to be affected by the free shrinkage of the paste phase, aggregate content and the stiffness of both phases. The model was then verified to be effective for simulating concrete shrinkage by comparing the predicted results with the autogeneous and drying shrinkage test results on mortar and concrete specimens.
Computational Fluid Dynamics Modeling Studies on Bacterial Flagellar Motion
Kumar, Manickam Siva,Philominathan, Pichai Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.3
The study of bacterial flagellar swimming motion remains an interesting and challenging research subject in the fields of hydrodynamics and bio-locomotion. This swimming motion is characterized by very low Reynolds numbers, which is unique and time reversible. In particular, the effect of rotation of helical flagella of bacterium on swimming motion requires detailed multi-disciplinary analysis. Clear understanding of such swimming motion will not only be beneficial for biologists but also to engineers interested in developing nanorobots mimicking bacterial swimming. In this paper, computational fluid dynamics (CFD) simulation of a three dimensional single flagellated bacteria has been developed and the fluid flow around the flagellum is investigated. CFD-based modeling studies were conducted to find the variables that affect the forward thrust experienced by the swimming bacterium. It is found that the propulsive force increases with increase in rotational velocity of flagellum and viscosity of surrounding fluid. It is also deduced from the study that the forward force depends on the geometry of helical flagella (directly proportional to square of the helical radius and inversely proportional to pitch).
Sirisawat Juengjaroennirachon,Naris Pratinthong,Pichai Namprakai,Taveewat Suparos 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1
This research focused on application of a heat transfer device, a Thermosyphon system energy storage unit (TSES unit), to air conditioning systems. The aim was to experimentally investigate use of the TSES unit to provide energy savings and enhance the heat transfer of the refrigerant. The TSES unit was installed between the compressor and the condenser. R-22, R-410A and R-134a refrigerants were used as working fluids in the thermosyphon heat pipe. Comparison of a conventional air conditioning system with the TSES unit-based air conditioning system shows that R-134a provides the best performance enhancement of the investigated refrigerants. The results show that the TSES unit-based system with R-134a reduced the refrigerant temperature at the condenser inlet to 11.67 o C, had the highest coefficient of performance with an increase of 22.75 %, increased the system’s cooling by 19.62 % and reduced power consumption by up to 3.76 %. This confirms that the device can lead to real energy savings.
Analysis of Microstructure and Properties of Autoclaved Aerated Concrete Wall Construction Materials
Tawatchai Charinpanitkul,Yothin Ungkoon,Chadchart Sittipunt,Pichai Namprakai,Wanvisa Jetipattaranat,Kyo-Seon Kim 한국공업화학회 2007 Journal of Industrial and Engineering Chemistry Vol.13 No.7
Microstructure analyses in non-autoclaved aerated concrete (Non-AAC) and autoclaved aerated concrete (AAC) were conducted using optical microscopic and scanning electron microscopic (SEM) methods, while their chemical analyses were also carried out using X-ray diffraction (XRD). Laboratory investigation including physiothermal properties and field tests using four lab-scale houses built with the Non-AAC and AAC blocks were also compared. It could be observed that the AAC exhibited properties superior to that of the Non-AAC. Interestingly, the AAC blocks could provide lower humidity accumulation than the Non-AAC blocks, resulting in possibility to prevent mold growth in such construction materials.