Hemodynamic prediction in patent ductus arteriosus morphologies

Patent ductus arteriosus (PDA) is a condition in which the ductus arteriosus remain opened after birth, causing the blood to shunt through from the aorta to the pulmonary artery. However, due to the complicated nature of the arterial geometry, the flow characteristic inside the PDA is not fully understood, since simplified model are commonly used in researches. This study aims to identify the hemodynamic characteristic in three different patient-specific morphologies. Computational modeling via computational fluid dynamic (CFD) is implemented to predict the blood flow behavior in different PDA morphologies. The result shows that low wall shear stress is observed at the region where the flow recirculation occurs. High wall shear stress is observed in the pulmonary artery due to increase of flow velocity at the insertion point of PDA. The PDA morphologies exhibit left-to-right shunt, which diverts approximately 10% of blood flow from the aorta to the pulmonary artery. The highest shunted blood flow is found in TR LPA morphology. High value of OSI indicates the changes of wall shear stress vector. It is observed that DS LPA has the highest area covered by OSI which presents better hemodynamic characteristic as compared to other morphology

Chemical Stabilization of Amorphous Peat Using Cement and Fly Ash at Different Water Additive Ratios

Peat is a very problematic soil as it is poor in strength. However, previous researchers have proven that the compressive strength of peat can be improved by using various methods of soil improvement including chemical stabilization method. In this study, cement and fly ash and lime were additives used and were mixed with amorphous peat at various water additive ratios. To replicate actual stabilization on site, water additive ratio is proposed as to allow stabilization to be performed at natural water content of the peat. Peat samples were collected from Kampung Endap, Samarahan and mixed at its natural moisture content with cement and with fly ash and lime at different water additive ratios of 3.0, 3.5, 4.0, 4.5 and 5.0. The compressive and bearing strengths of the samples were obtained by the unconfined compressive strength (UCS) test and California Bearing Ratio (CBR) test respectively. The results of the study have shown that there is marginal strength gained after 28 and 56 days of air curing period. The peat samples stabilized with cement at 3.5 water additive ratio recorded the highest value with UCS value of 69.48 kPa after 56 days of curing and 0.52 % for CBR test after 28 days curing period. These strength values obtained are lower compared to published data from previous studies. Different technique of mixing in the laboratory that is mixing peat at its natural water content with varied amount of additives at selected water additive ratio as opposed to mixing at maximum dry density and optimum moisture content that is mostly performed in laboratory contributes to the outcome. However, this study has proven that there is an increase in compressive and bearing strengths of stabilized peat in its natural water content compared to original peat without stabilizer

Chemical Stabilization of Amorphous Peat Using Cement and Fly Ash at Different Water Additive Ratios

Peat is a very problematic soil as it is poor in strength. However, previous researchers have proven that the compressive strength of peat can be improved by using various methods of soil improvement including chemical stabilization method. In this study, cement and fly ash and lime were additives used and were mixed with amorphous peat at various water additive ratios. To replicate actual stabilization on site, water additive ratio is proposed as to allow stabilization to be performed at natural water content of the peat. Peat samples were collected from Kampung Endap, Samarahan and mixed at its natural moisture content with cement and with fly ash and lime at different water additive ratios of 3.0, 3.5, 4.0, 4.5 and 5.0. The compressive and bearing strengths of the samples were obtained by the unconfined compressive strength (UCS) test and California Bearing Ratio (CBR) test respectively. The results of the study have shown that there is marginal strength gained after 28 and 56 days of air curing period. The peat samples stabilized with cement at 3.5 water additive ratio recorded the highest value with UCS value of 69.48 kPa after 56 days of curing and 0.52 % for CBR test after 28 days curing period. These strength values obtained are lower compared to published data from previous studies. Different technique of mixing in the laboratory that is mixing peat at its natural water content with varied amount of additives at selected water additive ratio as opposed to mixing at maximum dry density and optimum moisture content that is mostly performed in laboratory contributes to the outcome. However, this study has proven that there is an increase in compressive and bearing strengths of stabilized peat in its natural water content compared to original peat without stabilizer

Dengue fatality prediction using data mining

Dengue fever, a mosquito-borne tropical disease caused by the dengue virus is life-threatening. In Malaysia, although necessary control measures have been carried out, the number of dengue fever cases keeps increasing. Among the measures, dengue vector control appears to be the most effective way to control the spread of the dengue virus particularly in Malaysia. The aim of this research is to study the current implementation of dengue outbreak control in Malaysia and predict dengue fever cases using data mining techniques. Real data on dengue fever and weather are collected from the Ministry of Health in its Perak Tengah district office and Perak Meteorological office respectively. Different data mining classification techniques are applied onto these data with the performance of each technique is measured. The results highlight the best performance among techniques used.Keywords: data mining; prediction; dengue; classification

Optimization Of Wireless Pricing Scheme

The wireless service providers obtain surplus fromconsumers who applied the service. That pricing strategyis developed by considering the linearity factors, elasticityprice, price factors, acceptance factor and unit serviceprice. Previous researches are focussed on the introductionof the models in general. This new approach of the modelis by considering the model as the nonlinear programmingproblem that can be solved optimally using LINGO 13.0.The optimal solution could give information on decisionvariables and objective function to maximize the revenuefor the providers. The several objectives to be achieved byservice providers are by setting the increment ordecrement of price change due to QoS change and amountof QoS value

The Use of GPR in Delineating an Iron Sand Boundary and the Determination of Its Electromagnetic Wave Velocity: A Case Study in Jepara, Central Java

 Exploring the vertical extent of iron sand deposit is challenging as conventional geophysical methods (electrical resistivity, geomagnetic, and seismic refraction) are inappropriate and unsuccessful in delineating the iron sand deposit from the bedrock. Ground-penetrating radar (GPR) offers a solution to the above problem as radar is not affected negatively by the physical properties of iron sand. In the year 2003, a RAMAC's GPR survey was carried out in the coast of Bayuran in the Regency of Jepara, Central Java to map the distribution of sub-bottom iron sand. The sand is highly magnetic. The survey used 100 MHz antennas. The survey is also complimented by a novel method in determining the electromagnetic (EM) wave velocity of iron sand. Combination of reflection profiling and CMP sounding was deployed. Results of CMP sounding were processed using CMP-semblance analysis that produces the RMS velocity in velocity-time spectra. The RMS velocity is then converted to interval velocity using Dix's formula and is found to be about 135 mm/ns. Meanwhile, combination of magnetic susceptibility, relative permittivity, and dissipation factors produces radiowaves velocity of iron sand as a function of frequency. The velocities of radiowaves estimated from laboratory match that estimated from CMP analysis

Development Of Control Circuit For Single Phase Inverter Using Atmel Microcontroller.

This paper presents the development of control circuit for single phase inverter using Atmel microcontroller. The attractiveness of this configuration is the elimination of a microcontroller to generate sinusoidal pulse width modulation (SPWM) pulses

A Review on Carbon Fiber Reinforced Polymer as Wrapping Structures For Pipeline

To maintain the continuous product flow in the pipe, the durability of the pipe structure is achieved through pipe insulation. The composite material will be used as the main material, since it may have the combined characteristics of the constituents or have substantially different properties than the individual constituents. Replacing the damaged pipe with a new one will not only consume high cost but also will create a complication for product flow. As to alleviate such situations this research focusses on using the carbon fiber as the wrapping material. To identify the suitable design and optimization of laminated carbon fiber on piping systems, the defect, leakage and imperfection on pipe should be identified. The effect of different laminate optimization through Classical Laminate Theory CLT and experimental data too need to be considered as it changes the mechanical properties of the composite material. The microstructure of the composite too will be validated as an extra reference for the theoretical and experimental data on its effect in the microstructure after the loadin

A Review on Carbon Fiber Reinforced Polymer as Wrapping Structures For Pipeline

To maintain the continuous product flow in the pipe, the durability of the pipe structure is achieved through pipe insulation. The composite material will be used as the main material, since it may have the combined characteristics of the constituents or have substantially different properties than the individual constituents. Replacing the damaged pipe with a new one will not only consume high cost but also will create a complication for product flow. As to alleviate such situations this research focusses on using the carbon fiber as the wrapping material. To identify the suitable design and optimization of laminated carbon fiber on piping systems, the defect, leakage and imperfection on pipe should be identified. The effect of different laminate optimization through Classical Laminate Theory CLT and experimental data too need to be considered as it changes the mechanical properties of the composite material. The microstructure of the composite too will be validated as an extra reference for the theoretical and experimental data on its effect in the microstructure after the loadin

Comparative computational study of mechanical behavior in self-expanding femoropopliteal stents

The use of the stent to treat peripheral artery disease (PAD) is increased and the proportion of failures also increases. The femoropopliteal artery (FPA) experiences a high deformation ratio compared to the cardiovascular artery due to limp flexion and daily activities that could lead to stent failure, as well as increasing the number of observed mortality and morbidity. In the present work, two of the common PAD stent design models represented as STENT I and STENT II were analyzed by using of finite element method (FEM) to simulate the most mechanical loading modes that could occur in FPA, such as axial tension and compression, torsion, three-point bending and radial compression to give a good understanding of deformation that affected stent inside the in-vivo. The gradual force load was used to simulate all modes, the force values are 0.25 N, 0.5 N, 1.5 N, 2.5 N, 3.5 N and 5.5 N until the stent models obtain the yield-point. The comparison of stent models (STENT I, STENT II) was performed in terms of graphs of total deformation, force-stress and stress-strain for all test modes. The similarity ratio of the total deformation in axial tension and the compression mode for STENT I and STENT II was 17% and that may indicate that STENT I obtained a high deformation value instead of STENT II, while, the torsion similarity ratio was 86% which could show a good agreement in this mode, as well as the similarity ratio, was 78% of the total three-point bending deformation and the value of the similarity ratio in the radial compression mode was 23%. Still unclear what is the clinical mode of mechanical deformation that is more important than others with changing the length of the lesion and stent diameter, and the fatigue life test provides a better understanding of the mechanical tests that must be sought