Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7

Search results for: auscultation

7 Strengthening of Bridges by Additional Prestressing

Authors: A. Bouhaloufa, T. Kadri, S. Zouaoui, A. Belhacene

Abstract:

To put more durable bridges, it is important to maintain existing structures, rather than investing in new structures. Instead of demolishing the old bridge and replace them with new, we must preserve and upgrade using better methods of diagnosis, auscultation and repair, the interest of this work is to increase the bearing capacity bridges damaged by additional prestressing, this type of reinforcement is growing continuously. In addition to excellent static strength, prestressing also has a very high resistance to fatigue, so it is suitable to solve the problem of failure of the bearing capacity of the bridges. This failure often comes to the development of overloads in quantity and quality, that is our daily traffic has increased and become very complicated, on the other hand its constituents are advanced in weight and speed and therefore almost all old bridges became unable to support the movement of the latter and remain disabled to all these problems. The main purpose of this work includes the following three aspects: - Determination of the main diseases and factors affecting the deterioration of bridges in Algeria, - Evaluation of the bearing capacity of bridges, - Proposal technical reinforcement to improve the bearing capacity of a degraded structure.

Keywords: bridges, repair, auscultation, diagnosis, pathology, additional prestressing

Procedia PDF Downloads 520
6 Android – Based Wireless Electronic Stethoscope

Authors: Aw Adi Arryansyah

Abstract:

Using electronic stethoscope for detecting heartbeat sound, and breath sounds, are the effective way to investigate cardiovascular diseases. On the other side, technology is growing towards mobile. Almost everyone has a smartphone. Smartphone has many platforms. Creating mobile applications also became easier. We also can use HTML5 technology to creating mobile apps. Android is the most widely used type. This is the reason for us to make a wireless electronic stethoscope based on Android mobile. Android based Wireless Electronic Stethoscope designed by a simple system, uses sound sensors mounted membrane, then connected with Bluetooth module which will send the heart auscultation voice input data by Bluetooth signal to an android platform. On the software side, android will read the voice input then it will translate to beautiful visualization and release the voice output which can be regulated about how much of it is going to be released. We can change the heart beat sound into BPM data, and heart beat analysis, like normal beat, bradycardia or tachycardia.

Keywords: wireless, HTML 5, auscultation, bradycardia, tachycardia

Procedia PDF Downloads 259
5 Automated Heart Sound Classification from Unsegmented Phonocardiogram Signals Using Time Frequency Features

Authors: Nadia Masood Khan, Muhammad Salman Khan, Gul Muhammad Khan

Abstract:

Cardiologists perform cardiac auscultation to detect abnormalities in heart sounds. Since accurate auscultation is a crucial first step in screening patients with heart diseases, there is a need to develop computer-aided detection/diagnosis (CAD) systems to assist cardiologists in interpreting heart sounds and provide second opinions. In this paper different algorithms are implemented for automated heart sound classification using unsegmented phonocardiogram (PCG) signals. Support vector machine (SVM), artificial neural network (ANN) and cartesian genetic programming evolved artificial neural network (CGPANN) without the application of any segmentation algorithm has been explored in this study. The signals are first pre-processed to remove any unwanted frequencies. Both time and frequency domain features are then extracted for training the different models. The different algorithms are tested in multiple scenarios and their strengths and weaknesses are discussed. Results indicate that SVM outperforms the rest with an accuracy of 73.64%.

Keywords: pattern recognition, machine learning, computer aided diagnosis, heart sound classification, and feature extraction

Procedia PDF Downloads 128
4 Automated Recognition of Still’s Murmur in Children

Authors: Sukryool Kang, James McConnaughey, Robin Doroshow, Raj Shekhar

Abstract:

Still’s murmur, a vibratory heart murmur, is the most common normal innocent murmur of childhood. Many children with this murmur are unnecessarily referred for cardiology consultation and testing, which exacts a high cost financially and emotionally on the patients and their parents. Pediatricians to date are not successful at distinguishing Still’s murmur from murmurs of true heart disease. In this paper, we present a new algorithmic approach to distinguish Still’s murmur from pathological murmurs in children. We propose two distinct features, spectral width and signal power, which describe the sharpness of the spectrum and the signal intensity of the murmur, respectively. Seventy pediatric heart sound recordings of 41 Still’s and 29 pathological murmurs were used to develop and evaluate our algorithm that achieved a true positive rate of 97% and false positive rate of 0%. This approach would meet clinical standards in recognizing Still’s murmur.

Keywords: AR modeling, auscultation, heart murmurs, Still's murmur

Procedia PDF Downloads 304
3 2D Numerical Modeling of Ultrasonic Measurements in Concrete: Wave Propagation in a Multiple-Scattering Medium

Authors: T. Yu, L. Audibert, J. F. Chaix, D. Komatitsch, V. Garnier, J. M. Henault

Abstract:

Linear Ultrasonic Techniques play a major role in Non-Destructive Evaluation (NDE) for civil engineering structures in concrete since they can meet operational requirements. Interpretation of ultrasonic measurements could be improved by a better understanding of ultrasonic wave propagation in a multiple scattering medium. This work aims to develop a 2D numerical model of ultrasonic wave propagation in a heterogeneous medium, like concrete, integrating the multiple scattering phenomena in SPECFEM software. The coherent field of multiple scattering is obtained by averaging numerical wave fields, and it is used to determine the effective phase velocity and attenuation corresponding to an equivalent homogeneous medium. First, this model is applied to one scattering element (a cylinder) in a homogenous medium in a linear-elastic system, and its validation is completed thanks to the comparison with analytical solution. Then, some cases of multiple scattering by a set of randomly located cylinders or polygons are simulated to perform parametric studies on the influence of frequency and scatterer size, concentration, and shape. Also, the effective properties are compared with the predictions of Waterman-Truell model to verify its validity. Finally, the mortar viscoelastic behavior is introduced in the simulation in order to considerer the dispersion and the attenuation due to porosity included in the cement paste. In the future, different steps will be developed: The comparisons with experimental results, the interpretation of NDE measurements, and the optimization of NDE parameters before an auscultation.

Keywords: attenuation, multiple-scattering medium, numerical modeling, phase velocity, ultrasonic measurements

Procedia PDF Downloads 187
2 Procedure for Monitoring the Process of Behavior of Thermal Cracking in Concrete Gravity Dams: A Case Study

Authors: Adriana de Paula Lacerda Santos, Bruna Godke, Mauro Lacerda Santos Filho

Abstract:

Several dams in the world have already collapsed, causing environmental, social and economic damage. The concern to avoid future disasters has stimulated the creation of a great number of laws and rules in many countries. In Brazil, Law 12.334/2010 was created, which establishes the National Policy on Dam Safety. Overall, this policy requires the dam owners to invest in the maintenance of their structures and to improve its monitoring systems in order to provide faster and straightforward responses in the case of an increase of risks. As monitoring tools, visual inspections has provides comprehensive assessment of the structures performance, while auscultation’s instrumentation has added specific information on operational or behavioral changes, providing an alarm when a performance indicator exceeds the acceptable limits. These limits can be set using statistical methods based on the relationship between instruments measures and other variables, such as reservoir level, time of the year or others instruments measuring. Besides the design parameters (uplift of the foundation, displacements, etc.) the dam instrumentation can also be used to monitor the behavior of defects and damage manifestations. Specifically in concrete gravity dams, one of the main causes for the appearance of cracks, are the concrete volumetric changes generated by the thermal origin phenomena, which are associated with the construction process of these structures. Based on this, the goal of this research is to propose a monitoring process of the thermal cracking behavior in concrete gravity dams, through the instrumentation data analysis and the establishment of control values. Therefore, as a case study was selected the Block B-11 of José Richa Governor Dam Power Plant, that presents a cracking process, which was identified even before filling the reservoir in August’ 1998, and where crack meters and surface thermometers were installed for its monitoring. Although these instruments were installed in May 2004, the research was restricted to study the last 4.5 years (June 2010 to November 2014), when all the instruments were calibrated and producing reliable data. The adopted method is based on simple linear correlations procedures to understand the interactions among the instruments time series, verifying the response times between them. The scatter plots were drafted from the best correlations, which supported the definition of the limit control values. Among the conclusions, it is shown that there is a strong or very strong correlation between ambient temperature and the crack meters and flowmeters measurements. Based on the results of the statistical analysis, it was possible to develop a tool for monitoring the behavior of the case study cracks. Thus it was fulfilled the goal of the research to develop a proposal for a monitoring process of the behavior of thermal cracking in concrete gravity dams.

Keywords: concrete gravity dam, dams safety, instrumentation, simple linear correlation

Procedia PDF Downloads 233
1 A Patent Foramen Ovale as a Potential Indication for Systemic Thrombolysis in Acute Pulmonary Embolism

Authors: M. E. Nuver, F. M. M. Meijer, M. Goeijenbier

Abstract:

Systemic thrombolysis is recommended in patients with obstructive shock due to a pulmonary embolism. According to the current guidelines, thrombolysis, is not indicated in normotensive patients with intermediate risk pulmonary embolism. This is mainly due to an increased bleeding risk. The same is the case in isolated hypoxic respiratory failure. We present a case of a patient without hemodynamic instability, but with a intermediate risk acute pulmonary embolism. The case was complicated due to an intracardiac shunt through a patent foramen ovale (PFO). This PFO was aggravated by mechanical ventilation. We contemplate whether a PFO could be an additional thrombolysis indication in acute pulmonary embolism. A 47 year-old female attended the emergency department with a three day history of progressive shortness of breath. At physical examination, we observed a female in respiratory distress with tachypnea (30 breaths per minute) and severe hypoxia with a blood oxygen saturation of 60%. She was tachycardic (130 beats per minute) but was normotensive (165/75 mmHg). She had normal heart sounds an pulmonary auscultation revealed no abnormalities. Chest X-ray showed no abnormalities and a chest computed tomography angiography revealed severe saddle pulmonary embolism with lung infarction in the right lower lobe and dilatation of the right ventricle. Patient was admitted to the intensive care unit and continuous unfractionated heparin was initiated. The respiratory distress deteriorated and positive pressure mechanical ventilation was commenced. After the initiation of positive pressure ventilation the patients hypoxia worsened, hence an intra-cardiac shunt was suspected. A trans thoracic echocardiogram revealed a right-to-left shunt through a PFO. Because the severe and progressive hypoxia, systemic thrombolysis was considered to accelerate the resolution of pulmonary embolism. According to literature the prevalence of PFO lies between 25-30%. The presence of a right-to-left intracardiac shunt in patients with acute pulmonary embolism is associated with a remarkable increase in mortality. Furthermore, arterial embolism and ischaemic stroke are seen in higher numbers in these patients. Mechanical ventilation may increase the fraction of intracardiac shunt. Currently a PFO, in patients needing mechanical ventilation, is not an indication for thrombolysis in any guideline. Systemic thrombolysis in patients with a pulmonary embolism and severe hypoxia due to shunting is pathophysiological conceivable. Acceleration of the resolution of pulmonary embolism, will reduce right ventricular pressure thereby reducing the shunt fraction. A possible detriment of systemic thrombolysis is an increased bleeding risk. Furthermore, it may be a (relative) contra-indication for the initiation of Extracorporeal Membrane Oxygenation. With these possible drawbacks in mind, we did not administer systemic thrombolysis and therapy with unfractioned heparine was continued. After 3 days, mechanical ventilation could be discontinued and patient was discharged from the intensive care unit. Patients with acute pulmonary embolism and a concomitant intracardiac shunt through a patent foramen ovale have a high risk of mortality and severe complications. Positive mechanical ventilation may increase the shunt fraction and aggravate hypoxaemia. Systemic thrombolysis may be considered but it remains unclear whether the potential benefits outweigh the increased bleeding risk.

Keywords: intracardiac shunt, patent foramen ovale, pulmonary embolism, systemic thrombolysis

Procedia PDF Downloads 6