Wyniki wyszukiwania - BazTech

1

ECG signals-based automated diagnosis of congestive heart failure using Deep CNN and LSTM architecture

Kusuma S., Jothi K. R.

Biocybernetics and Biomedical Engineering

|

2022

|

Vol. 42, no. 1

247--257

EN

In humans, Congestive Heart Failure (CHF) refers to the chronic progressive condition that drastically influences the pumping potentiality of the heart muscle. This CHF has the possibility of increasing health expenditure, morbidity, mortality and minimized quality of life. In this context, Electrocardiogram (ECG) is considered as the simplest and a non-invasive diagnosis method that aids in detecting and demonstrating the realizable changes in CHF. However, diagnosing CHF based on manual exploration of ECG signals is frequently impacted by errors as duration and small amplitude of the signals either investigated separately or in the integration is determined to neither specific nor sensitive. At this juncture, the reliability and diagnostic objectivity of ECG signals during the CHF detection process may be enhanced through the inclusion of automated computer-aided system. In this paper, Deep CNN and LSTM Architecture (DCNN-LSTM)-based automated diagnosis system is proposed for detecting CHF using ECG signals. In specific, CNN is included for the purpose of extracting deep features and LSTM is used for attaining the objective of CHF detection using the extracted features. This proposed DCNN-LSTM is evolved with minimal pre-processing of ECG signals and does not involve any classification process or manual engineered features during diagnosis. The experimentation of the proposed DCNN-LSTM conducted using the real time ECG signals datasets confirmed an accuracy of 99.52, sensitivity of 99.31%, specificity of 99.28%, F-Score of 98.94% and AUC of 99.9%, respectively.

2

Investigations on pool boiling of refrigerant R141b outside a horizontal tube

Baki Touhami, Aris Abdelkader, Tebbal Mohamed

Archive of Mechanical Engineering

|

2021

|

LXVIII, nr 1

77--92

EN

Boiling produces vapor with a phase change by absorbing a consistent amount of heat. Experimentation and modeling can help us better understand this phenomenon. The present study is focused on the heat transfer during the nucleate pool boiling of refrigerant R141b on the surface of a horizontal copper tube. The results of the experiment were compared with four correlations drawn from the literature, and the critical heat flux was examined for different pressures and also compared with the predicted values. Simulating boiling with two-phase models allowed us to infer the plot of the temperature distribution around the tube and compared it to results from other work.

3

Model of heat transfer in the stagnation point of rapidly evaporating microjet

Mikielewicz D., Muszyński T., Mikielewicz J.

Archives of Thermodynamics

|

2012

|

Vol. 33, no. 1

139-152

EN

The paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 [my]m respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling but the boiling curves are showing a smaller value of critical heat flux (CHF) that the stagnant pool boiling. Values of CHF are also reduced with decreasing liquid subcooling. Theoretical model of surface cooling by evaporating microjet impingement in the stagnation point was described theoreticaly. Results of experiments were compared with predictions by the model showing a good consistency.

4

Experimental and theoretical study of dryout in annular flow in small diameter channels

Mikielewicz D., Gliński M., Wajs J.

Archives of Thermodynamics

|

2011

|

Vol. 32, no. 1

89-109

EN

In the paper the experimental analysis of dryout in small diameter channels is presented. The investigations were carried out in vertical pipes of internal diameter equal to 1.15 mm and 2.3 mm. Low-boiling point fluids such as SES36 and R123 were examined. The modern experimental techniques were applied to record liquid film dryout on the wall, among the others the infrared camera. On the basis of experimental data an empirical correlation for predictions of critical heat flux was proposed. It shows a good agreement with experimental data within the error band of 30%. Additionally, a unique approach to liquid film dryout modeling in annular flow was presented. It led to the development of the three-equation model based on consideration of liquid mass balance in the film, a two-phase mixture in the core and gas. The results of experimental validation of the model exhibit improvement in comparison to other models from literature.